The document discusses reproduction in various organisms through different modes like regeneration, fragmentation, budding, spore formation, and vegetative propagation.
It provides examples of regeneration in Planaria and Hydra where cut pieces of their bodies can regrow into complete organisms. Fragmentation is described in Spirogyra where long filaments break into fragments that develop into new individuals. Spore formation in Rhizopus fungus and budding in Hydra is also explained. Vegetative propagation in Bryophyllum using leaf buds is mentioned.
1. The document discusses various modes of reproduction in living organisms including asexual reproduction methods like binary fission, budding, spore formation, regeneration, fragmentation, and vegetative propagation.
2. It also describes sexual reproduction which involves the fusion of male and female gametes to form a zygote that develops into a new organism.
3. DNA replication during reproduction is highlighted as essential for transmitting characteristics from parents to offspring, with variations introduced through imperfect replication allowing for evolution of species over time.
Here's a concise introduction suitable for a class 10 science lesson on how organisms reproduce:
Introduction to Reproduction:
Reproduction is the biological process through which living organisms produce offspring of their own kind. It ensures the continuation of a species over generations. Organisms reproduce in different ways, depending on their characteristics and environmental factors. There are two main types of reproduction: asexual and sexual. Asexual reproduction involves a single parent and produces offspring that are genetically identical to the parent. Sexual reproduction involves two parents and produces offspring with genetic variations. Both types of reproduction are essential for the survival and evolution of species. Throughout this lesson, we will explore the fascinating mechanisms by which organisms reproduce and the significance of reproduction in maintaining life on Earth.
For more information, visit-www.vavaclasses.com
CBSE Previous Years Questions and Answers, Chapter - 8, How do Organisms Repr...Shivam Parmar
The document contains 26 multiple choice questions about human reproduction. It begins with definitions of key terms like fertilization and functions of parts of the male and female reproductive systems. Some questions differentiate between sexual and asexual reproduction, or compare reproductive processes between species. The last few questions focus specifically on the human reproductive cycle and placenta, describing its structure and role in exchanging gases and nutrients between mother and fetus.
6. All plants produce __________ by mitosis and __________ by meiosi.pdfarjunanenterprises
6. All plants produce __________ by mitosis and __________ by meiosis. A)spores, gametes
B)gametes, gametes C)gametes, spores D)spores, spores E)spores, gametes and spores 7. In a
heterosporous life cycle, the microspore develops into the _____ gametophyte, while the
megaspore develops into the ______ gametophyte. A)female, male B)male, female C)diploid,
haploid D)haploid, diploid E)None of the above 8. Asexual reproduction in liverworts is
accomplished by A)gametophytes. B)spores. C)gemmae. D)tracheids. 9. You are walking along
a roadside and find a plant with the following characteristics: very thin waxy cuticle, stomata,
simple leaves in whorls around a central stem, independent sporophyte and gametophyte,
sporangia in strobili. This plant is most likely a member of which of the following phyla?
A)Bryophyta B)Sphenophyta C)Pterophyta D)Lycophyta 10. Plants differ from algae in that only
plants A)are photosynthetic. B)are multicellular. C)possess chlorophyll. D)have multicellular
embryos protected by the parent. E)are eukaryotic. 11. Which statement about the alternation of
generations in plants is not true? A) The plant life cycle is characterized by diploid and haploid
forms. B)Meiosis occurs in sporangia. C)Gametes are always produced by meiosis. D)The
zygote is the first cell of the sporophyte generation. E)The gametophyte and sporophyte differ
genetically. 12. The most abundant gymnosperm phylum today is A) Cycadophyta. B)
Ginkgophyta. C) Gnetophyta. D) Coniferophyta. E) None of the above 13. Coniferous
gymnosperms, such as pines, depend primarily on __________ for pollination; thus, the plants
produce large quantities of pollen that disperse over large areas during the spring. A) insects B)
birds C) water D) wind E) mammals 14. An evolutionary trend that runs throughout the plant
kingdom is that the sporophyte generation ___ and is more independent of the gametophyte, and
the gametophyte generation _____ and is more dependent upon the sporophyte. A) becomes
smaller, becomes smaller B) becomes larger, becomes smaller C) becomes smaller, becomes
larger D) becomes larger, becomes larger E) does not change in size, becomes larger 15.
Angiosperms differ from other plants in that two male gametes, contained within a single male
gametophyte, participate in fertilization events. One sperm nucleus combines with the egg to
produce a diploid zygote. The other sperm nucleus combines with two other haploid nuclei of the
female gametophyte. This process is called A) biparental inheritance. B) multiple paternity. C)
double fertilization. D) biparental fertilization. E) multiple fertilization. 16. The reproductive
organ of angiosperms is the A)sporangium. B) flower. C) cone. D) archegonium. E) sporophyte.
17. The prominent components of Earth\'s modern land flora in most areas are A) angiosperms.
B) gymnosperms. C) ferns. D) bryophytes. E) club mosses. 18. Flowers with insect pollination
have showy A) petals. B) sepals. C) anthers. D) fruits 19. In a.
There are two main types of reproduction - asexual and sexual. Asexual reproduction involves mitosis and produces offspring that are genetically identical to the parent. It is common in single-celled and simple organisms. Sexual reproduction involves meiosis and the fusion of male and female gametes, producing offspring that are not identical to the parents. It plays an important role in evolution and is seen in more complex multicellular organisms. Some examples of asexual reproduction discussed include binary fission, budding, regeneration and vegetative propagation using various plant structures like roots, stems and leaves. Sexual reproduction and the formation of gametes via meiosis is also summarized.
The document discusses the different modes of reproduction in organisms. It describes asexual reproduction methods like vegetative reproduction, fission, budding, and regeneration. Potatoes and Protococcus are used as examples. Sexual reproduction requires two parents and produces offspring with unique gene combinations. Flower structure and reproduction in plants is demonstrated using gumamela. Both asexual and sexual reproduction ensure the continuity of life.
1. The document contains updates to content in the NCERT Class 11 Biology textbook, including corrections, additions, and replacements of text, diagrams, and figures.
2. Updates include adding more detail about fungal cell walls, correcting terminology related to algae and viruses, and adding sections on prions and anatomical details of plants and animals.
3. Diagrams are also added or updated regarding biological structures and processes such as ribosomes, protein structure, and mitosis.
1. The document discusses various modes of reproduction in living organisms including asexual reproduction methods like binary fission, budding, spore formation, regeneration, fragmentation, and vegetative propagation.
2. It also describes sexual reproduction which involves the fusion of male and female gametes to form a zygote that develops into a new organism.
3. DNA replication during reproduction is highlighted as essential for transmitting characteristics from parents to offspring, with variations introduced through imperfect replication allowing for evolution of species over time.
Here's a concise introduction suitable for a class 10 science lesson on how organisms reproduce:
Introduction to Reproduction:
Reproduction is the biological process through which living organisms produce offspring of their own kind. It ensures the continuation of a species over generations. Organisms reproduce in different ways, depending on their characteristics and environmental factors. There are two main types of reproduction: asexual and sexual. Asexual reproduction involves a single parent and produces offspring that are genetically identical to the parent. Sexual reproduction involves two parents and produces offspring with genetic variations. Both types of reproduction are essential for the survival and evolution of species. Throughout this lesson, we will explore the fascinating mechanisms by which organisms reproduce and the significance of reproduction in maintaining life on Earth.
For more information, visit-www.vavaclasses.com
CBSE Previous Years Questions and Answers, Chapter - 8, How do Organisms Repr...Shivam Parmar
The document contains 26 multiple choice questions about human reproduction. It begins with definitions of key terms like fertilization and functions of parts of the male and female reproductive systems. Some questions differentiate between sexual and asexual reproduction, or compare reproductive processes between species. The last few questions focus specifically on the human reproductive cycle and placenta, describing its structure and role in exchanging gases and nutrients between mother and fetus.
6. All plants produce __________ by mitosis and __________ by meiosi.pdfarjunanenterprises
6. All plants produce __________ by mitosis and __________ by meiosis. A)spores, gametes
B)gametes, gametes C)gametes, spores D)spores, spores E)spores, gametes and spores 7. In a
heterosporous life cycle, the microspore develops into the _____ gametophyte, while the
megaspore develops into the ______ gametophyte. A)female, male B)male, female C)diploid,
haploid D)haploid, diploid E)None of the above 8. Asexual reproduction in liverworts is
accomplished by A)gametophytes. B)spores. C)gemmae. D)tracheids. 9. You are walking along
a roadside and find a plant with the following characteristics: very thin waxy cuticle, stomata,
simple leaves in whorls around a central stem, independent sporophyte and gametophyte,
sporangia in strobili. This plant is most likely a member of which of the following phyla?
A)Bryophyta B)Sphenophyta C)Pterophyta D)Lycophyta 10. Plants differ from algae in that only
plants A)are photosynthetic. B)are multicellular. C)possess chlorophyll. D)have multicellular
embryos protected by the parent. E)are eukaryotic. 11. Which statement about the alternation of
generations in plants is not true? A) The plant life cycle is characterized by diploid and haploid
forms. B)Meiosis occurs in sporangia. C)Gametes are always produced by meiosis. D)The
zygote is the first cell of the sporophyte generation. E)The gametophyte and sporophyte differ
genetically. 12. The most abundant gymnosperm phylum today is A) Cycadophyta. B)
Ginkgophyta. C) Gnetophyta. D) Coniferophyta. E) None of the above 13. Coniferous
gymnosperms, such as pines, depend primarily on __________ for pollination; thus, the plants
produce large quantities of pollen that disperse over large areas during the spring. A) insects B)
birds C) water D) wind E) mammals 14. An evolutionary trend that runs throughout the plant
kingdom is that the sporophyte generation ___ and is more independent of the gametophyte, and
the gametophyte generation _____ and is more dependent upon the sporophyte. A) becomes
smaller, becomes smaller B) becomes larger, becomes smaller C) becomes smaller, becomes
larger D) becomes larger, becomes larger E) does not change in size, becomes larger 15.
Angiosperms differ from other plants in that two male gametes, contained within a single male
gametophyte, participate in fertilization events. One sperm nucleus combines with the egg to
produce a diploid zygote. The other sperm nucleus combines with two other haploid nuclei of the
female gametophyte. This process is called A) biparental inheritance. B) multiple paternity. C)
double fertilization. D) biparental fertilization. E) multiple fertilization. 16. The reproductive
organ of angiosperms is the A)sporangium. B) flower. C) cone. D) archegonium. E) sporophyte.
17. The prominent components of Earth\'s modern land flora in most areas are A) angiosperms.
B) gymnosperms. C) ferns. D) bryophytes. E) club mosses. 18. Flowers with insect pollination
have showy A) petals. B) sepals. C) anthers. D) fruits 19. In a.
There are two main types of reproduction - asexual and sexual. Asexual reproduction involves mitosis and produces offspring that are genetically identical to the parent. It is common in single-celled and simple organisms. Sexual reproduction involves meiosis and the fusion of male and female gametes, producing offspring that are not identical to the parents. It plays an important role in evolution and is seen in more complex multicellular organisms. Some examples of asexual reproduction discussed include binary fission, budding, regeneration and vegetative propagation using various plant structures like roots, stems and leaves. Sexual reproduction and the formation of gametes via meiosis is also summarized.
The document discusses the different modes of reproduction in organisms. It describes asexual reproduction methods like vegetative reproduction, fission, budding, and regeneration. Potatoes and Protococcus are used as examples. Sexual reproduction requires two parents and produces offspring with unique gene combinations. Flower structure and reproduction in plants is demonstrated using gumamela. Both asexual and sexual reproduction ensure the continuity of life.
1. The document contains updates to content in the NCERT Class 11 Biology textbook, including corrections, additions, and replacements of text, diagrams, and figures.
2. Updates include adding more detail about fungal cell walls, correcting terminology related to algae and viruses, and adding sections on prions and anatomical details of plants and animals.
3. Diagrams are also added or updated regarding biological structures and processes such as ribosomes, protein structure, and mitosis.
This document defines asexual reproduction and describes its various types. It explains that asexual reproduction involves a single parent producing offspring that are genetically identical. Various types of asexual reproduction are described, including fission, fragmentation, budding, parthenogenesis, spore production, and vegetative propagation. Examples of each type are provided. The objectives are to define asexual reproduction, describe its different types, and classify organisms by their reproductive methods.
1. The document describes the process of sexual reproduction in flowering plants including microsporogenesis, megasporogenesis, and double fertilization.
2. It defines key terms like anther, ovule, embryo sac, and discusses the layers of the anther and structures of the ovule.
3. The formation of the female gametophyte or embryo sac from a megaspore mother cell and its cells including the egg, central, and synergid cells are summarized.
This document provides information about protists and fungi. It begins with an introduction to the module, which will cover protists in Lesson 1 and fungi in Lesson 2. Lesson 1 then discusses the different types of protists, including plant-like protists like algae and animal-like protists like amoebas. It explains how protists obtain food, move, and reproduce. Protists play important ecological roles but some can also harm humans and other organisms.
Ch-1 Reproduction in organisms -Biology NEET MCQ English Mediumnirav soni
This document contains 20 multiple choice questions about reproduction in organisms. The questions cover topics like asexual reproduction methods in planaria and bryophyllum, vegetative propagation in plants, the lifecycle of hydra, cloning, chromosome numbers during plant reproduction processes like in endosperm and gametes. The questions test understanding of key concepts like budding, regeneration, cloning, syngamy, and chromosome numbers during sexual reproduction in flowering plants.
This document summarizes the evolution of seeds, beginning with an overview of seed development. Seeds evolve from ovules, which contain the nucellus and are enveloped by integuments. The integuments develop into the seed coat. Within the nucellus, a megaspore develops into a haploid megagametophyte. Gymnosperm and angiosperm megagametophytes differ in structure. After pollination, a pollen tube transfers sperm for fertilization. The review will discuss seed anatomy, the endosperm, dormancy evolution, early seed-like structures, and the evolution of seed size. It provides context on seed plant phylogeny and the importance
The document discusses asexual reproduction, which is the process of producing offspring from a single parent. It describes several forms of asexual reproduction including regeneration, budding, binary fission, and mitosis. Regeneration occurs when an organism breaks into parts that can each grow into a new organism. Budding involves a new cell developing and pinching off from the parent organism. Binary fission is the process that prokaryotic cells undergo to replicate. Mitosis is the process that eukaryotic cells undergo to replicate through the phases of interphase and cell division.
The document discusses asexual reproduction, which is the process of producing offspring from a single parent. It describes several forms of asexual reproduction including regeneration, budding, binary fission, and mitosis. Regeneration occurs when an organism breaks into parts that can each grow into a new organism. Budding involves a new cell developing and pinching off from the parent organism. Binary fission is the process where a prokaryotic cell grows and splits into two identical daughter cells. Mitosis is the process of cell division that produces two daughter cells with identical DNA to the parent cell.
The document discusses asexual reproduction, which is reproduction that requires only one parent. It defines several forms of asexual reproduction including regeneration, budding, binary fission, and mitosis. Budding is when a new organism develops from a protrusion on the parent organism. Regeneration occurs when an organism breaks into parts that can each grow into a new organism. Binary fission is the process that single-celled prokaryotes use to reproduce. Mitosis is the process that eukaryotic cells use to replicate their DNA and divide.
The document discusses asexual reproduction, which is reproduction that requires only one parent. It defines several forms of asexual reproduction including regeneration, budding, binary fission, and mitosis. Budding is when a new organism develops from a protrusion on the parent organism. Regeneration occurs when an organism breaks into parts that can each grow into a new organism. Binary fission is the process that single-celled prokaryotes use to reproduce. Mitosis is the process that eukaryotic cells use to replicate their DNA and divide.
1. It is widely agreed that the plant kingdom arose from A)Eumycota..pdfarishmarketing21
1. It is widely agreed that the plant kingdom arose from A)Eumycota. B)Chrysophyta.
C)Phaeophyta. D)Rhodophyta. E)Chlorophyta.
2. A universal feature of the life cycle of plants is A)morphologically identical haploid and
diploid stages. B)genetically identical haploid and diploid stages. C)alteration of generations
between heteromorphic haploid gametophytes and diploid sporophytes. D)All of the above
E)None of the above
3. Several evolutionary adaptations to land are shared by all plants. These shared adaptations do
not include A)waxy protective coverings. B)support against gravity. C)means of taking up water
from the soil. D)protective structures for the new sporophyte. E)water transport by xylem.
4. Ferns are in which phylum? A) Lycophyta B) Anthocerophyta C) Hepatophyta D) Pterophyta
E) Bryophyta
5. The bryophytes are dependent on water for reproduction because A) sperm are passively
transported to eggs by water. B) gametogenesis only occurs when the plants are moist. C) eggs
and sperm are released into water and then unite. D) sperm must swim through water to reach
and fertilize eggs. E) None of the above
6. All plants produce __________ by mitosis and __________ by meiosis. A)spores, gametes
B)gametes, gametes C)gametes, spores D)spores, spores E)spores, gametes and spores
7. In a heterosporous life cycle, the microspore develops into the _____ gametophyte, while the
megaspore develops into the ______ gametophyte. A)female, male B)male, female C)diploid,
haploid D)haploid, diploid E)None of the above
8. Asexual reproduction in liverworts is accomplished by A)gametophytes. B)spores. C)gemmae.
D)tracheids.
9. You are walking along a roadside and find a plant with the following characteristics: very thin
waxy cuticle, stomata, simple leaves in whorls around a central stem, independent sporophyte
and gametophyte, sporangia in strobili. This plant is most likely a member of which of the
following phyla? A)Bryophyta B)Sphenophyta C)Pterophyta D)Lycophyta
10. Plants differ from algae in that only plants A)are photosynthetic. B)are multicellular.
C)possess chlorophyll. D)have multicellular embryos protected by the parent. E)are eukaryotic.
11. Which statement about the alternation of generations in plants is not true? A) The plant life
cycle is characterized by diploid and haploid forms. B)Meiosis occurs in sporangia. C)Gametes
are always produced by meiosis. D)The zygote is the first cell of the sporophyte generation.
E)The gametophyte and sporophyte differ genetically.
12. The most abundant gymnosperm phylum today is A) Cycadophyta. B) Ginkgophyta. C)
Gnetophyta. D) Coniferophyta. E) None of the above
13. Coniferous gymnosperms, such as pines, depend primarily on __________ for pollination;
thus, the plants produce large quantities of pollen that disperse over large areas during the spring.
A) insects B) birds C) water D) wind E) mammals
14. An evolutionary trend that runs throughout the plant kingdom is that the sporophyte
generation ___ and .
1. Early embryonic development in insects begins immediately after fertilization inside the egg and involves cleavage, formation of the blastoderm and germ band, gastrulation, formation of embryonic membranes, blastokinesis, and development of organ systems and appendages. 2. Cleavage involves the repeated mitotic division of the zygote, forming many energids that migrate to form the blastoderm. Some energids remain in the yolk as vitellophages. 3. Gastrulation forms the mesoderm and endoderm layers through invagination, growing plates, or cell proliferation. This establishes the three germ layers that develop into tissues and organ systems.
This document provides an overview of asexual and sexual reproduction. It discusses various modes of asexual reproduction like binary fission, multiple fission, regeneration, fragmentation, budding and spore formation. It also covers vegetative propagation and tissue culture. For sexual reproduction, it describes the floral parts like carpels and stamens and the processes of pollination, fertilization and double fertilization in flowering plants.
The document provides instructions for a final exam in mycology. It states that the exam has two sections, Section A which is compulsory and Section B which requires answering three of five questions. Section A includes six short answer questions covering topics like distinguishing fungi from plants, industrial uses of fungi, differences between molds and yeasts, and terms like biotrophs, necrotrophs, parasexuality, and mycotoxins. Section B includes longer answer questions requiring descriptions of fungal reproduction, advantages of incomplete septa, heterokaryosis, growth conditions for fungi, glycolysis and energy production in fungi, and differences between batch and continuous culture techniques.
This document provides a 40 question biology classification test with multiple choice answers. It includes questions testing knowledge of archaebacteria characteristics, mycorrhiza, uses of E. coli in research, diatom shell composition, kingdom classification systems, fungal reproduction, virus structure, bacterial shapes, decomposer roles and more. The test is scored out of 160 total marks and takes approximately 45 minutes to complete.
Sexual reproduction occurs in flowering plants through flowers which contain both male and female reproductive structures. The male structures called stamens produce pollen grains which contain the male gametes. The female structures called pistils contain ovules which house egg cells. Pollination is the transfer of pollen grains to the stigma of the pistil. This triggers a process called double fertilization where two male gametes fuse with an egg cell and polar nuclei to form a zygote and endosperm which nourish the developing seed. Growth in multicellular organisms involves increases in cell number through cell division and cell size through cell enlargement and differentiation into specialized cell types.
This document contains answers to questions about cells and cell organelles. Key points:
- The shape of a cell is determined by its location and function.
- Unicellular organisms are single-celled, like Euglena and Amoeba. Multicellular organisms have many cells, like humans and birds.
- Mitochondria are known as the "powerhouse of the cell" because that is where cellular respiration occurs to produce energy.
BRCC BIOL 121 FINAL SPRING 20151. E coli is a shortened name for.docxAASTHA76
BRCC BIOL 121 FINAL SPRING 2015
1. E coli is a shortened name for a bacterium that lives in our gut. According to the rules of binomial nomenclature it is properly written as _______________.
a. Escherichia COLI
b. Escherichia Coli
c. Escherichia coli
d. escherichia coli
e. escherichia coli
2. What does the term “biodiversity” refer to in the field of biology?
a. Total number of species on earth
b. Genetic variation that exists within populations all of the earth’s species
c. Total number of Earth’s ecosystems
d. All of the above are correct
3. Prokaryotic cells are classified in Domain(s) _______
a. Archaea
b. Bacteria
c. Eukarya
d. Archaea and Bacteria
e. Archaea, Bacteria and Eukarya
4. (
4. The shape of this bacterium is __________ and the attachment filaments radiating out are called_________
a
. bacillus…………. flagella
b
. coccus……………cilia
c.
spirilla
…………..
pili
d
. bacillus………… pili
e
. vibrio…………….cilia
)
5. A certain bacterium can withstand heating, drying and toxic chemicals that would kill most other bacteria. This indicates that it is probably able to form a __________
a. Pseudopodia
b. Conjugation tube
c. Endospore
d. Flagellum
e. Endotoxins
(
6.What
ecological role is played by cyanobacteria ?
a. photosynthetic
producers that make sugar and pump oxygen into the atmosphere
b
. decomposers of dead leaves and dead animals
c. chemosynthetic
producers
d
pathogens of plants and animals
e. predators
of other bacteria
)
6.
7. The term phytoplankton applies to photosynthetic, microscopic floating organisms such as________
a. Protozoan ciliates and flagellates
b. Aquatic plants
c. Dinoflagellates, diatoms and some unicellular or colonial green algae
d. Macroalgae and seaweeds
e. Fungus like protists such as slime molds
8. Which of the following statements is false?
a. Most protists are aquatic.
b. Protists are eukaryotes.
c. Most protists are unicellular.
d. Protists have more complex cells than prokaryotes.
e. Photosynthetic protists are called protozoa.
9. (
9. Which of the following structures is used by amoebas to move and to eat?
a. microvilli
b. cilia
c. flagella
d. pseudopodia
e. tendrils
)
10. Into what kingdom do we place multicellular heterotrophic eukaryotes that acquire food by absorption from the environment and have cell walls made of chitin?
a. Plantae
b. Animalia
c. Protista
d. Fungi
e. Proteobacteria
11. (
11.
(See image to the left)
A
fungus surrounding a root
absorbs food from the plant
and in turn this fungus
provides water and minerals to the plant. This is a _________ relationship?
a
. parasitic
b
.
commensalistic
c
.
predatorial
d
. mutualistic
e
. competitive
)
12. (See image above). A fungus growing together with a plant root in a way that benefits both is
a(n)_______
a. Lichen
b. Epiphyte
c. Mycorrhizae
d. Hemiparasite
e. Halophyte
13. Which group shares the most recent common ancestor with land plants?
a. Fungi
b. Cyanobacteria
c. Brown algae
d. Green a ...
The document discusses reproduction in animals. It begins by explaining the importance of reproduction in ensuring the continuity of life across generations. It then describes the process of fertilization in humans, where a sperm fuses with an egg to form a single-celled zygote. The document provides questions and answers about internal and external fertilization, the development of a tadpole into a frog through metamorphosis, and the number of nuclei present in a zygote. It also includes true/false questions testing understanding of key reproduction terms and concepts.
1. The document discusses the evolution of seeds from early algal mats to complex angiosperms and gymnosperms.
2. It describes the key stages in seed development including pollination, fertilization, embryo and endosperm development, and seed coat formation.
3. Seed structure and function is explained for both monocotyledonous and dicotyledonous seeds, highlighting differences in embryo, endosperm, and food storage tissues between the two groups.
Reproduction allows organisms to produce new individuals of the same species in order to ensure species survival. During reproduction, DNA is copied and passed from parents to offspring, resulting in slight variations between individuals. This variation is important for species to adapt to environmental changes and evolve over time. There are two main types of reproduction - asexual, which involves a single parent, and sexual, which involves two individuals. In humans, sexual reproduction involves male and female reproductive systems and fertilization of an egg by sperm to produce an embryo that develops over nine months before birth.
This document defines asexual reproduction and describes its various types. It explains that asexual reproduction involves a single parent producing offspring that are genetically identical. Various types of asexual reproduction are described, including fission, fragmentation, budding, parthenogenesis, spore production, and vegetative propagation. Examples of each type are provided. The objectives are to define asexual reproduction, describe its different types, and classify organisms by their reproductive methods.
1. The document describes the process of sexual reproduction in flowering plants including microsporogenesis, megasporogenesis, and double fertilization.
2. It defines key terms like anther, ovule, embryo sac, and discusses the layers of the anther and structures of the ovule.
3. The formation of the female gametophyte or embryo sac from a megaspore mother cell and its cells including the egg, central, and synergid cells are summarized.
This document provides information about protists and fungi. It begins with an introduction to the module, which will cover protists in Lesson 1 and fungi in Lesson 2. Lesson 1 then discusses the different types of protists, including plant-like protists like algae and animal-like protists like amoebas. It explains how protists obtain food, move, and reproduce. Protists play important ecological roles but some can also harm humans and other organisms.
Ch-1 Reproduction in organisms -Biology NEET MCQ English Mediumnirav soni
This document contains 20 multiple choice questions about reproduction in organisms. The questions cover topics like asexual reproduction methods in planaria and bryophyllum, vegetative propagation in plants, the lifecycle of hydra, cloning, chromosome numbers during plant reproduction processes like in endosperm and gametes. The questions test understanding of key concepts like budding, regeneration, cloning, syngamy, and chromosome numbers during sexual reproduction in flowering plants.
This document summarizes the evolution of seeds, beginning with an overview of seed development. Seeds evolve from ovules, which contain the nucellus and are enveloped by integuments. The integuments develop into the seed coat. Within the nucellus, a megaspore develops into a haploid megagametophyte. Gymnosperm and angiosperm megagametophytes differ in structure. After pollination, a pollen tube transfers sperm for fertilization. The review will discuss seed anatomy, the endosperm, dormancy evolution, early seed-like structures, and the evolution of seed size. It provides context on seed plant phylogeny and the importance
The document discusses asexual reproduction, which is the process of producing offspring from a single parent. It describes several forms of asexual reproduction including regeneration, budding, binary fission, and mitosis. Regeneration occurs when an organism breaks into parts that can each grow into a new organism. Budding involves a new cell developing and pinching off from the parent organism. Binary fission is the process that prokaryotic cells undergo to replicate. Mitosis is the process that eukaryotic cells undergo to replicate through the phases of interphase and cell division.
The document discusses asexual reproduction, which is the process of producing offspring from a single parent. It describes several forms of asexual reproduction including regeneration, budding, binary fission, and mitosis. Regeneration occurs when an organism breaks into parts that can each grow into a new organism. Budding involves a new cell developing and pinching off from the parent organism. Binary fission is the process where a prokaryotic cell grows and splits into two identical daughter cells. Mitosis is the process of cell division that produces two daughter cells with identical DNA to the parent cell.
The document discusses asexual reproduction, which is reproduction that requires only one parent. It defines several forms of asexual reproduction including regeneration, budding, binary fission, and mitosis. Budding is when a new organism develops from a protrusion on the parent organism. Regeneration occurs when an organism breaks into parts that can each grow into a new organism. Binary fission is the process that single-celled prokaryotes use to reproduce. Mitosis is the process that eukaryotic cells use to replicate their DNA and divide.
The document discusses asexual reproduction, which is reproduction that requires only one parent. It defines several forms of asexual reproduction including regeneration, budding, binary fission, and mitosis. Budding is when a new organism develops from a protrusion on the parent organism. Regeneration occurs when an organism breaks into parts that can each grow into a new organism. Binary fission is the process that single-celled prokaryotes use to reproduce. Mitosis is the process that eukaryotic cells use to replicate their DNA and divide.
1. It is widely agreed that the plant kingdom arose from A)Eumycota..pdfarishmarketing21
1. It is widely agreed that the plant kingdom arose from A)Eumycota. B)Chrysophyta.
C)Phaeophyta. D)Rhodophyta. E)Chlorophyta.
2. A universal feature of the life cycle of plants is A)morphologically identical haploid and
diploid stages. B)genetically identical haploid and diploid stages. C)alteration of generations
between heteromorphic haploid gametophytes and diploid sporophytes. D)All of the above
E)None of the above
3. Several evolutionary adaptations to land are shared by all plants. These shared adaptations do
not include A)waxy protective coverings. B)support against gravity. C)means of taking up water
from the soil. D)protective structures for the new sporophyte. E)water transport by xylem.
4. Ferns are in which phylum? A) Lycophyta B) Anthocerophyta C) Hepatophyta D) Pterophyta
E) Bryophyta
5. The bryophytes are dependent on water for reproduction because A) sperm are passively
transported to eggs by water. B) gametogenesis only occurs when the plants are moist. C) eggs
and sperm are released into water and then unite. D) sperm must swim through water to reach
and fertilize eggs. E) None of the above
6. All plants produce __________ by mitosis and __________ by meiosis. A)spores, gametes
B)gametes, gametes C)gametes, spores D)spores, spores E)spores, gametes and spores
7. In a heterosporous life cycle, the microspore develops into the _____ gametophyte, while the
megaspore develops into the ______ gametophyte. A)female, male B)male, female C)diploid,
haploid D)haploid, diploid E)None of the above
8. Asexual reproduction in liverworts is accomplished by A)gametophytes. B)spores. C)gemmae.
D)tracheids.
9. You are walking along a roadside and find a plant with the following characteristics: very thin
waxy cuticle, stomata, simple leaves in whorls around a central stem, independent sporophyte
and gametophyte, sporangia in strobili. This plant is most likely a member of which of the
following phyla? A)Bryophyta B)Sphenophyta C)Pterophyta D)Lycophyta
10. Plants differ from algae in that only plants A)are photosynthetic. B)are multicellular.
C)possess chlorophyll. D)have multicellular embryos protected by the parent. E)are eukaryotic.
11. Which statement about the alternation of generations in plants is not true? A) The plant life
cycle is characterized by diploid and haploid forms. B)Meiosis occurs in sporangia. C)Gametes
are always produced by meiosis. D)The zygote is the first cell of the sporophyte generation.
E)The gametophyte and sporophyte differ genetically.
12. The most abundant gymnosperm phylum today is A) Cycadophyta. B) Ginkgophyta. C)
Gnetophyta. D) Coniferophyta. E) None of the above
13. Coniferous gymnosperms, such as pines, depend primarily on __________ for pollination;
thus, the plants produce large quantities of pollen that disperse over large areas during the spring.
A) insects B) birds C) water D) wind E) mammals
14. An evolutionary trend that runs throughout the plant kingdom is that the sporophyte
generation ___ and .
1. Early embryonic development in insects begins immediately after fertilization inside the egg and involves cleavage, formation of the blastoderm and germ band, gastrulation, formation of embryonic membranes, blastokinesis, and development of organ systems and appendages. 2. Cleavage involves the repeated mitotic division of the zygote, forming many energids that migrate to form the blastoderm. Some energids remain in the yolk as vitellophages. 3. Gastrulation forms the mesoderm and endoderm layers through invagination, growing plates, or cell proliferation. This establishes the three germ layers that develop into tissues and organ systems.
This document provides an overview of asexual and sexual reproduction. It discusses various modes of asexual reproduction like binary fission, multiple fission, regeneration, fragmentation, budding and spore formation. It also covers vegetative propagation and tissue culture. For sexual reproduction, it describes the floral parts like carpels and stamens and the processes of pollination, fertilization and double fertilization in flowering plants.
The document provides instructions for a final exam in mycology. It states that the exam has two sections, Section A which is compulsory and Section B which requires answering three of five questions. Section A includes six short answer questions covering topics like distinguishing fungi from plants, industrial uses of fungi, differences between molds and yeasts, and terms like biotrophs, necrotrophs, parasexuality, and mycotoxins. Section B includes longer answer questions requiring descriptions of fungal reproduction, advantages of incomplete septa, heterokaryosis, growth conditions for fungi, glycolysis and energy production in fungi, and differences between batch and continuous culture techniques.
This document provides a 40 question biology classification test with multiple choice answers. It includes questions testing knowledge of archaebacteria characteristics, mycorrhiza, uses of E. coli in research, diatom shell composition, kingdom classification systems, fungal reproduction, virus structure, bacterial shapes, decomposer roles and more. The test is scored out of 160 total marks and takes approximately 45 minutes to complete.
Sexual reproduction occurs in flowering plants through flowers which contain both male and female reproductive structures. The male structures called stamens produce pollen grains which contain the male gametes. The female structures called pistils contain ovules which house egg cells. Pollination is the transfer of pollen grains to the stigma of the pistil. This triggers a process called double fertilization where two male gametes fuse with an egg cell and polar nuclei to form a zygote and endosperm which nourish the developing seed. Growth in multicellular organisms involves increases in cell number through cell division and cell size through cell enlargement and differentiation into specialized cell types.
This document contains answers to questions about cells and cell organelles. Key points:
- The shape of a cell is determined by its location and function.
- Unicellular organisms are single-celled, like Euglena and Amoeba. Multicellular organisms have many cells, like humans and birds.
- Mitochondria are known as the "powerhouse of the cell" because that is where cellular respiration occurs to produce energy.
BRCC BIOL 121 FINAL SPRING 20151. E coli is a shortened name for.docxAASTHA76
BRCC BIOL 121 FINAL SPRING 2015
1. E coli is a shortened name for a bacterium that lives in our gut. According to the rules of binomial nomenclature it is properly written as _______________.
a. Escherichia COLI
b. Escherichia Coli
c. Escherichia coli
d. escherichia coli
e. escherichia coli
2. What does the term “biodiversity” refer to in the field of biology?
a. Total number of species on earth
b. Genetic variation that exists within populations all of the earth’s species
c. Total number of Earth’s ecosystems
d. All of the above are correct
3. Prokaryotic cells are classified in Domain(s) _______
a. Archaea
b. Bacteria
c. Eukarya
d. Archaea and Bacteria
e. Archaea, Bacteria and Eukarya
4. (
4. The shape of this bacterium is __________ and the attachment filaments radiating out are called_________
a
. bacillus…………. flagella
b
. coccus……………cilia
c.
spirilla
…………..
pili
d
. bacillus………… pili
e
. vibrio…………….cilia
)
5. A certain bacterium can withstand heating, drying and toxic chemicals that would kill most other bacteria. This indicates that it is probably able to form a __________
a. Pseudopodia
b. Conjugation tube
c. Endospore
d. Flagellum
e. Endotoxins
(
6.What
ecological role is played by cyanobacteria ?
a. photosynthetic
producers that make sugar and pump oxygen into the atmosphere
b
. decomposers of dead leaves and dead animals
c. chemosynthetic
producers
d
pathogens of plants and animals
e. predators
of other bacteria
)
6.
7. The term phytoplankton applies to photosynthetic, microscopic floating organisms such as________
a. Protozoan ciliates and flagellates
b. Aquatic plants
c. Dinoflagellates, diatoms and some unicellular or colonial green algae
d. Macroalgae and seaweeds
e. Fungus like protists such as slime molds
8. Which of the following statements is false?
a. Most protists are aquatic.
b. Protists are eukaryotes.
c. Most protists are unicellular.
d. Protists have more complex cells than prokaryotes.
e. Photosynthetic protists are called protozoa.
9. (
9. Which of the following structures is used by amoebas to move and to eat?
a. microvilli
b. cilia
c. flagella
d. pseudopodia
e. tendrils
)
10. Into what kingdom do we place multicellular heterotrophic eukaryotes that acquire food by absorption from the environment and have cell walls made of chitin?
a. Plantae
b. Animalia
c. Protista
d. Fungi
e. Proteobacteria
11. (
11.
(See image to the left)
A
fungus surrounding a root
absorbs food from the plant
and in turn this fungus
provides water and minerals to the plant. This is a _________ relationship?
a
. parasitic
b
.
commensalistic
c
.
predatorial
d
. mutualistic
e
. competitive
)
12. (See image above). A fungus growing together with a plant root in a way that benefits both is
a(n)_______
a. Lichen
b. Epiphyte
c. Mycorrhizae
d. Hemiparasite
e. Halophyte
13. Which group shares the most recent common ancestor with land plants?
a. Fungi
b. Cyanobacteria
c. Brown algae
d. Green a ...
The document discusses reproduction in animals. It begins by explaining the importance of reproduction in ensuring the continuity of life across generations. It then describes the process of fertilization in humans, where a sperm fuses with an egg to form a single-celled zygote. The document provides questions and answers about internal and external fertilization, the development of a tadpole into a frog through metamorphosis, and the number of nuclei present in a zygote. It also includes true/false questions testing understanding of key reproduction terms and concepts.
1. The document discusses the evolution of seeds from early algal mats to complex angiosperms and gymnosperms.
2. It describes the key stages in seed development including pollination, fertilization, embryo and endosperm development, and seed coat formation.
3. Seed structure and function is explained for both monocotyledonous and dicotyledonous seeds, highlighting differences in embryo, endosperm, and food storage tissues between the two groups.
Reproduction allows organisms to produce new individuals of the same species in order to ensure species survival. During reproduction, DNA is copied and passed from parents to offspring, resulting in slight variations between individuals. This variation is important for species to adapt to environmental changes and evolve over time. There are two main types of reproduction - asexual, which involves a single parent, and sexual, which involves two individuals. In humans, sexual reproduction involves male and female reproductive systems and fertilization of an egg by sperm to produce an embryo that develops over nine months before birth.
Best Digital Marketing Strategy Build Your Online Presence 2024.pptxpavankumarpayexelsol
This presentation provides a comprehensive guide to the best digital marketing strategies for 2024, focusing on enhancing your online presence. Key topics include understanding and targeting your audience, building a user-friendly and mobile-responsive website, leveraging the power of social media platforms, optimizing content for search engines, and using email marketing to foster direct engagement. By adopting these strategies, you can increase brand visibility, drive traffic, generate leads, and ultimately boost sales, ensuring your business thrives in the competitive digital landscape.
2. C
01. What happens when
(a) accidently, Planaria gets cut into many pieces
(b) Bryophyllum leaf falls on the wet soil
(c) on maturation sporangia of Rhizopus bursts?
(Delhi 2017)
3. C
Solutions:
(a) When Planaria accidently gets cut into many pieces then its each
piece grows into a complete organism. is is known as regeneration.
(b) When the Bryophyllum leaf falls on the wet soil, the buds present in
the notches along the leaf margin develop into new plants. is known
as vegetative propagation.
(c) The sporangia of Rhizopus contain cells or spores that can
eventually develop into new Rhizopus individuals when it bursts on
maturation.
5. C
Solutions:
Fungus Rhizopus reproduces by spore formation. During the
growth of Rhizopus, small rounded, bulb-like structures develop at
the top of the erect hyphae. Such structures are called sporangia.
Inside each sporangium, nucleus divides several times. Each
nucleus gets surrounded by a little amount of cytoplasm to become
spore. Large number of spores are formed inside each sporangium.
After sometime sporangium bursts and spores are released in the
air. When these spores land on food or soil, under favourable
conditions, they germinate into new individuals
6. C
3. What is vegetative propagation? State two advantages and two
disadvantages of this method. (AI 2017)
7. C
Solutions:
Vegetative propagation is a type of asexual reproduction in which the
plant parts other than seeds are used as a propagule. Advantages of
vegetative propagation :
(i) Desirable character of the plant can be preserved through g
generation.
(ii) Seedless plants can be grown through this method. Disadvantages of
vegetative propagation :
(i) Plants produced by this method posses less vigour and are more
prone to diseases.
(ii) Plants produced by this method show no genetic variation.
8. C
4. What is multiple fission? How does it occur in an organism? Explain
briefly. Name one organism which exhibits this type of reproduction.
(Delhi 2016)
9. C
Solutions:
Multiple fission refers to the process of asexual reproduction in which
many individuals are formed from a single parent. is method of
reproduction occurs in unfavourable conditions. e unicellular organism
develops a protective covering called cyst, over the cell. e nucleus of the
cell divides repeatedly producing many nuclei. Later on, each nucleus
is surrounded by small amount of cytoplasm and many daughter cells
are produced within the cyst.
When conditions are favourable the cyst breaks and small osprings are
liberated. is type of reproduction is seen in some protozoans, e.g.,
malarial parasite (Plasmodium).
10. C
5. Explain the term “regeneration” as used in relation to reproduction
of organisms. Describe briefly how regeneration is carried
out in multicellular organisms like Hydra.
(AI 2016)
11. C
Solutions:
The process of formation of entire organism from the body parts of a
fully differentiated organism is called regeneration. It occurs by
process of growth and development. Simple animal like Hydra shows
regeneration. When a small piece of Hydra breaks o it grows into
complete new Hydra.
During regeneration, the cells of cut body part of the organism divide
rapidly to make a mass of cells. e cells here move to their proper places
within the mass where they have to form different types of tissues. In
this way complete organism is regenerated.
12. C
6. In the context of reproduction of species state the main difference
between fission and fragmentation. Also give one example of each.
(AI 2016)
13. C
Solutions:
The main differences between fission and fragmentation are as follows:
Fission Fragmentation
(i) Occurs in unicellular
organisms.
Occurs in multicellular
organisms.
(ii) Body of organism
divides by mitotic
divisions into two or
more daughter cells.
E.g., Leishmania.
Body of the organism splits
into one or more fragments
and each fragment forms a
complete organism. E.g.,
Spirogyra.
14. C
7. What happens when
(a) Planaria gets cut into two pieces
(b) a mature Spirogyra lament attains considerable length
(c) on maturation sporangia burst?
(Foreign 2016)
15. C
Solutions:
(a) When Planaria is cut into two pieces then each piece grows into a
complete organism. is is known as regeneration.
(b) When a mature Spirogyra lament attains a considerable length it
breaks into small pieces called fragments. ese fragments grow into new
individuals and this mode of reproduction is called fragmentation.
(c) When a sporangium burst, large number of spores are released in
the air. When these spores land on food or soil, under favourable
conditions they germinate into new individuals.
16. C
8. What is vegetative propagation? List with brief explanation three
advantages of practicing this process for growing some types of
plants. Select two plants from the following which are grown by this
process : Banana, Wheat, Mustard, Jasmine, Gram
(Foreign 2016)
17. C
Solutions:
Vegetative propagation is an asexual method of reproduction in plants.
In this method, new plants are obtained from the parts of old plants
(like stems, roots and leaves), without the help of any reproductive
organs.
Advantages of vegetative propagation are as follows:
(i) Vegetative propagation is usually used for the propagation of those
plants which produce either very few seeds or do not produce viable
seeds.
(ii) Seedless plants can be obtained by artificial vegetative propagation.
18. C
(iii) Grafting is a propagation method which is very useful for fruit trees
and flowering bushes. It enables to combine the most desirable
characteristics of two plants.
(iv) Plants like rose, sugarcane, cactus, etc., can be rapidly propagated
through stem cuttings as this method produces new plants from just
one plant quickly without waiting for flowers and seeds. Banana
and jasmine are generally grown through vegetative propagation
method.
19. C
9. Explain budding in Hydra with the help of labelled diagrams only.
(Delhi 2015)
21. C
12. Explain the process of regeneration in Planaria. How is this process
different from reproduction?
(Foreign 2015, AI 2014)
22. C
Solutions:
Planaria possesses great power of regeneration. If the body of Planaria
somehow gets cut into a number of pieces, then each body piece can
regenerate into a complete Planaria by growing all the missing parts. is
is shown in following figure.
23. C
During the process of reproduction new organism is formed from the
complete parent organism however, during fragmentation, a
fragment of original parent body grows into new individual.
24. C
13. On cutting the body of an organism into many pieces, it was
observed that many of these pieces developed as new individuals.
Name the process and list two organisms in which this process may
be observed. Draw a schematic diagram to illustrate the changes
that are likely to be observed during the development of new
individuals in any one of the organisms named.
(Delhi 2014)
25. C
Solutions:
On cutting the body of an organism into many pieces, each of these
pieces develop as new individuals. This process is known as
regeneration. Hydra and Planaria are the organism in which this
process may be observed. Following is the diagram show development
of new individuals by regeneration of body parts of a parent Hydra.
26. C
15. List any two modes of asexual reproduction in animals. Under which
mode of reproduction is vegetative propagation placed and why?
List two advantages of vegetative propagation.
(AI 2014)
27. C
Solutions:
The two modes of asexual reproduction in animals are : (i) ssion (ii)
fragmentation. Vegetative propagation is placed under asexual mode of
reproduction because in this mode new plants are obtained from the
parts of old plants (like stems, roots and leaves), without the help of
any reproductive organs. Also refer to answer 40.
28. C
4. Name the life process of an organism that helps in the growth of its
population. (AI 2015)
30. C
04. What is binary fission in organisms? With the help of suitable
diagrams, describe the mode of reproduction in Amoeba.
(AI 2011)
31. C
Solutions:
Binary fission is the division of adult parental body into two nearly
equal daughter cells. It is the simplest and most common method of
asexual reproduction found in protistan protozoans i.e. Amoeba,
Paramecium, etc.
Amoeba reproduces by binary fission by dividing its body into two
parts. When the Amoeba cell has reached its maximum size of growth,
then first the nucleus of Amoeba lengthens and divides into two parts.
Aer that the cytoplasm of Amoeba divides to form two smaller Amoeba
(called daughter amoebae).
Diagrammatic representation of binary fission in Amoeba is as follows :
33. C
05. (a) What is spore formation?
(b) Draw a diagram showing spore formation in Rhizopus.
(c) List two advantages for organisms to reproduce themselves
through spores.
(Foreign 2011)
34. C
Solutions:
(a) Spore formation is the process of formation of microscopic
reproductive structures called spores. ese spores when detaches
from the parent gives rise to a new individual. Reproduction by the
formation of spores is a common method of asexual reproduction in
some bacteria and most of the fungi.
(b) Following figure shows the process of spore formation in Rhizopus.
35. C
(c) Two advantages to spore producing organism are as follows:
(i) Spores help organism to survive harsh environmental conditions as
spores are covered by thick walls which protect them until they
come in contact with moist surface and germinate.
(ii) Spores are generally very small and light. Therefore, it ensures easy
dispersal by wind, water and animal.
36. C
6. (a) Name the mode of reproduction of the following organisms and
state the important feature of each mode:
(i) Planaria
(i) Hydra
(iii) Rhizopus
(b) We can develop new plants from the leaves of Bryophyllum.
Comment.
(c) List two advantages of vegetative propagation over other
modes of reproduction. (2020)
37. C
Solutions:
(a) (i) Planaria – Regeneration - Regeneration of organism from its cut
body parts occurs by the process of growth and development.
– Regeneration is an asexual mode of reproduction common in lower
plants and animals.
(ii) Hydra - Budding
– In budding, a small part of the body of the parent organism grows
out as a bud which on detaching forms a new organism.
– Budding occurs in yeast, some Protozoans and certain lower
animals.
38. C
Solutions:
(iii) Rhizopus – Spores
- Spores are usuallyproduced in sporangia.
- Spore formation is a common method of an asexual reproduction in
bacteria and most of the fungi.
(b) The leaves of a Bryophyllum have special type of buds in their
margins. These buds may get detached from the leaves, fall to
ground and then grow to produce new Bryophyllum plants. The
buds can also drop to the ground together with the leaf and then
grow to produce new plants.
39. C
01. Define the term pollination. Differentiate between self-pollination and
cross-pollination’ What is the significance of pollination? (2020)
40. C
Solutions:
The process of transfer of pollen grains from anther of a flower to
the stigma of the same flower or another flower of the same species
is known as pollination. The two modes of pollination are self
pollination and cross pollination. Differences between self
pollination and cross pollination are as follows:
41. C
02. (a) What provides nutrition to human sperms? State the genetic
constitution of a sperm.
(b) Mention the chromosome pair present in a zygote which determines
the sex of (i) a female child and (ii) a male child. (2020)
42. C
Solutions:
(a) The secretions of seminal vesicles and prostate gland provides
nutrition to the human sperms and also make their further
transport easier. The genetic constitution of a sperm can be 50olo
have X chromosome and 507o have Y chromosome.
(b) (i) XX - Female child
(ii) XY - Male child
43. C
04 State the changes that take place in the uterus when :
(a) Implantation of embryo has occurred.
(b) Female gamete/egg is not fertilised. (Delhi 2017)
44. C
Solutions:
(a) Implantation is the close attachment of the blastocyst (young multicellular
embryo) to the uterine wall. It is followed by a number of developmental
changes in the thickened wall of uterus. An intimate connection between
the fetal membrane and the uterine wall called placenta is formed. is is a
disc which is embedded in the uterine wall. e placenta serves as the
nutritive, respiratory and excretory organ of the fetus.
(b) As the ovary releases one egg every month, the uterus also prepares itself,
every month to receive fertilised egg by making its lining thick and spongy
to nourish the embryo if fertilisation had taken place. When the female
gamete/egg is not fertilised, this lining is not needed any longer. So, the
lining slowly breaks and comes out through vagina as blood and mucus. is
cycle takes place every month and is known as menstrual cycle.
45. C
05. List any two steps involved in sexual reproduction and write its two
advantage. (Delhi 2017)
46. C
Solutions:
The two main steps involved in sexual reproduction are:
(i) formation of male and female gametes.
(ii) fusion of a male gamete with a female gamete to form a new cell
called zygote by the process of fertilisation.
The two important advantages of sexual reproduction are:
(i) It promotes diversity of characters in the offsprings through genetic
variations.
(ii) It plays an important role in continuous evolution of better organisms
that may lead to the origin of new species.
47. C
06. List three techniques that have been developed to prevent
pregnancy. Which one of these techniques is not meant for males?
How does the use of these techniques have a direct impact on the
health and prosperity of a family? (AI 2017)
48. C
Solutions:
Methods developed to prevent pregnancy are:
(i) Barrier method, i.e., use of condoms, diaphragm, etc.
(ii) Chemical method, i.e., use of oral pills or vaginal pills.
(iii) Surgical method, i.e., vasectomy and tubectomy. Out of these
methods, chemical method is not meant for males. Use of these
techniques help to keep control over number of children in a family,
which directly effects prosperity of a family. One of the most common
reason for deterioration of women’s health is frequent conception and
child bearing. Controlled childbirth will directly affect women health
and this will indirectly affect the prosperity of family and nation.
49. C
07. How do organisms, whether reproduced asexually or sexually
maintain a constant chromosome number through several
generations? Explain with the help of suitable example. (Delhi 2016)
50. C
Solutions:
In organisms reproducing asexually, only single parent is involved in reproduction.
Therefore, amount of DNA remains same from parent to offspring. For example in
Amoeba, whole organism divides into two daughter individuals by binary fission.
Therefore, amount of DNA remain constant. In organisms reproducing sexually.
Reproduction take place with the help of formation of haploid gametes. Gametes
are special type of cells called reproductive cells which contain only half the
amount of DNA as compared to the normal body cells of an organism. So, when a
male gamete combines with a female gamete during sexual reproduction, then the
new cell ‘zygote’ will have the normal amount of DNA. For example, the human
sperm has 23 chromosomes and the human egg (or ovum) has also 23
chromosomes. So, when a sperm and an egg fuse together during fertilisation, then
the zygote formed will have 23 + 23 = 46 chromosomes, which is the normal
number of chromosomes.
51. C
08. Name the parts A, B and C shown in the following diagram and
state one function of each. (Delhi 2016)
52. C
Solutions:
In the given figure part A is anther, part B is style and part C is ovule.
Anther (A) is a part of male reproductive organ of flower called stamen.
Large number of pollen grains are formed inside anther. Style (B) and
ovule (C) are parts of female reproductive organ of flower called carpel /
pistil. Style is a long conducting tube which gives the passage to pollen
tube carrying male gametes so that it reaches ovary which contains one
or more ovules. Ovules contain female gamete or egg. On fertilisation
ovary converts into fruit and ovules give rise to seeds.
53. C
09. Suggest three contraceptive methods to control the size of human
population which is essential for the health and prosperity of a
country. State the basic principle involved in each. (Delhi 2016)
54. C
Solutions:
Three contraceptive methods which can help control human population are:
(i) Condoms : It is a mechanical barrier which does not allow sperms and ovum to
meet hence prevents fertilisation. Condoms are made of thin rubber/latex sheath
used to cover the penis in the male and vagina/cervix in female just before coitus
(intercourse) so that the ejaculated semen is not released in the female
reproductive tract.
(ii) Intrauterine devices (IUDs) : These are devices inserted by doctors or expert
nurses in the uterus through vagina. ese are presently available as non-
medicated IUDs, copper releasing IUDs (CuT, etc.) and hormone releasing IUDs.
They increase phagocytosis of sperms within uterus and suppress sperm motility
and its fertilising capacity. They also make uterus unsuitable for implantation
and cervix hostile to sperms.
55. C
(iii) Oral pills : Oral pills contain progesterone alone or a combination of
progestogen and estrogen. They inhibit ovulation and make uterus
unsuitable for implantation, hence prevent fertilisation.
56. C
10. What are the functions of testis in the human male reproductive
system? Why are these located outside the abdominal cavity? Who is
responsible for bringing about changes in appearance seen in boys at
the time of puberty? (Delhi 2016)
57. C
Solutions:
Testes, in human males, are the primary reproductive organs. ey are the
site of sperm formation. e testes also produce male sex hormone
testosterone. Testes are located outside the abdominal cavity because
sperm formation requires a lower temperature than normal body
temperature. e temperature of the testes in the scrotum is about 2–2.5°C
lower than normal body How do Organisms Reproduce? 135
temperature. is temperature is ideal for sperm formation and
development. Hormone testosterone brings about the development of
secondary sexual character during puberty in boys like growth of facial
hair, deepening of voice, growth of scrotum and penis, accumulation of
muscle mass, etc., and also regulates formation of sperms.
58. C
11. What is meant by pollination? Name and differentiate between the two
modes of pollination in flowering plants. (Delhi 2016)
59. C
Solutions:
The process of transfer of pollen grains from anther of a flower to the
stigma of the same flower or another flower of the same species is
known as pollination. e two modes of pollination are self pollination and
cross pollination. Differences between self pollination and cross
pollination are:
61. C
12. (a) List two reasons for the appearance of variations among the
progeny formed by sexual reproduction.
(b) (i) Name the part marked A in the diagram.
(ii) How does A reaches part B?
(iii) State the importance of the part C.
(iv) What happens to the part marked D after
fertilisation is over? (AI 2016)
62. C
Solutions:
(a) Variations arise in sexually reproducing organisms on account of the
following :
(i) Genetic variations occur of because DNA copying mechanism is not
absolutely accurate.
(ii) Creation of new combinations of genetic variations because variations
from two individuals combine during fusion of gametes.
63. C
(b) (i) A is pollen grain.
(ii) Part B is stigma. It is the part of pistil (female reproductive organ)
that receives pollen grains. Pollen grain reach stigma through various
agencies like wind, water, insect, etc.
(iii) Pollen tube (C) carries male gametes to the ovule present in ovary.
Male gametes fuse with egg and secondary nucleus to give rise to
zygote and endosperm.
(iv) Female gamete (D) fuses with male gamete and converts to embryo
after fertilisation.
64. C
13. What is pollination? List its two types and write a distinguishing
feature between the two. (Foreign 2016)
66. C
14. What is sexual reproduction? List its four significances. (Foreign 2016)
67. C
Solutions:
Sexual reproduction is the process of production of offspring by the fusion of male
and female gametes.
Here haploid gametes fuse to form diploid zygote which develop into a mature
organism. Significances of sexual reproduction are as follows:
(i) Sexual reproduction gives rise to genetic variations because of genetic
recombination that takes place during fusion of gametes.
(ii) Progenies arising through sexual reproduction sometimes show better
combination of traits and get better adapted to their surroundings.
(iii) Genetic recombination, interaction, etc. during sexual reproduction provide
vigour and vitality to the offspring.
(iv) Variations in genes play an important role in evolution.
68. C
15. Name the reproductive parts of an angiosperm. Where are these parts
located? Explain in brief the structure of its female reproductive parts.
(Foreign 2016)
69. C
Solutions:
The reproductive organs of an angiosperm are stamen (male
reproductive part) and carpel/pistil (female reproductive part). ese are
located in the flowers of an angiospermic plant. e given diagram shows
the structure of female reproductive part of a flower.