Cell division occurs through mitosis and meiosis. Mitosis produces two identical daughter cells and is used for growth and tissue repair. Meiosis produces gametes like sperm and eggs with half the number of chromosomes and is used for sexual reproduction. The cell cycle includes interphase, where the cell grows and DNA replicates, and the M phase where mitosis occurs. Mitosis involves prophase, metaphase, anaphase and telophase stages to divide the cell. Meiosis involves two cell divisions, meiosis I and meiosis II, to produce four haploid cells from one diploid cell. This ensures genetic variation in offspring.
Continuation of the cell structure and function. This presentation highlights the cell cycle and concentrate on how cell division occur and the steps involved in cell dividing.
2018/2019
It is the presentation on the MEIOSIS phase of the Cell division.
It includes all the details and definitions that are related to the topic of meiosis with the labelled diagrams.
If you have any query or a question, you may ask in the comment box.
thanks.
Continuation of the cell structure and function. This presentation highlights the cell cycle and concentrate on how cell division occur and the steps involved in cell dividing.
2018/2019
It is the presentation on the MEIOSIS phase of the Cell division.
It includes all the details and definitions that are related to the topic of meiosis with the labelled diagrams.
If you have any query or a question, you may ask in the comment box.
thanks.
The slides contain all about meiosis. in this slides i collected all information about meiosis. which is useful for everyone.
so watch these slides and comment for any problems.
thanks
This presentation explains the topic of CELL CYCLE and CELL DIVISION.
It includes cell mitosis of both Plant cell and Animal cell with labelled diagrams.
Human digestive system structure and function
overview
Major organs
Mouth
Esophagus
Stomach
small intestine
large intestine
Acessory organs:
Liver
gall bladder
Pancreas.
Human digestive system
Major organs
Mouth
Esophagus
Stomach
small intestine
large intestine.
Acessory organs:
Liver
Gall bladder
Pancreas.
MAJOR ORGANSThe Mouth
pH: 7
The first part of the digestive system
the entry point of food.
Structures in the mouth that aids digestion
Teeth – cut, tear, crush and grind food.
Salivary glands – produce and secrete saliva into the oral cavity.
saliva
moistens the food
contains enzymes (ptyalin or salivary amylase)
begins digestion of starch into smaller polysaccharides.
Function:
Mechanical digestion.
increasing surface area for faster chemical digestion.
The Esophagus
a tube connecting the mouth to the stomach
running through the Thoracic cavity.
Location:
lies behind windpipe (Trachea).
The trachea has as an epiglottis
preventing food from entering the windpipe,
moving the food to the esophagus while swallowing.
Food travels down the esophagus, through a series of involuntary rhythmic contractions (wave-like) called peristalsis.
Function:
The lining of the esophagus secretes mucus
lubricating
to support the movement of food.
Esophageal sphincter:
bolus reaches the stomach
must pass through a muscular ringed valve called the esophageal sphincter (Cardiac Sphincter).
Function:
prevent stomach acids from back flowing into the esophagus.
Stomach
J-shaped muscular sac
Has inner folds (rugae)
Increasing surface area of the stomach.
Function:
Stomach performs mechanical digestion
HOW By churning the bolus and mixing it with the gastric juices
secreted by the lining of the stomach.
GASTRIC JUICES HCl, salts, enzymes, water and mucus)
HCL helps break down of food and kills bacteria that came along with the food.
The bolus is now called Chyme.
Enzymes in stomach:
Acidic environment
HCl secreation
kill any microbes that are found in the bolus,
creating a pH of 2.
Mucus prevents the stomach from digesting itself.
Pepsin secreation
responsible for initiating the breakdown of proteins (in )food.
hydrolyzes proteins to yield polypeptides.
pH is 2, the enzyme from the salivary glands stops breaking down carbohydrates.
Pyloric sphincter:
chyme moves from the stomach to the small intestine.
It passes through a muscular ringed sphincter called the pyloric sphincter.
stomach does not digest itselfWhy ?
Protective Mechanism:
three protective mechanisms.
First the stomach only secretes small amounts of gastric juices until food is present.
Second the secretion of mucus coats the lining of the stomach protecting it from the gastric juices.
The third mechanism is the digestive enzyme pepsin is secreted in an inactive protein c
Cells and its components(Anatomy) Easy explanationSwatilekha Das
Cells and its components,discussion on cell membrane, cytoplasm, nucleus with pictures....
easy explanation of anatomy topic for 1 st year GNM & B.Sc nursing students...
Comment to get explanation on your required topics.....
please like and share and follow.....
The cell is the basic structural, functional, and biological unit of all known organisms. A cell is the smallest unit of life. Cells are often called the "building blocks of life". The study of cells is called cell biology, cellular biology, or cytology.
Meiosis and Cell Cycle Stages ppt
Cell Cycle ppt
Cell Division ppt
Meiosis ppt
Stages of Meiosis ppt
Meiosis-I ppt
Stages of Meiosis-I ppt
Homologous Chromosomes ppt
Crossing Over ppt
Meiosis-I ppt
Stages of Meiosis-I ppt
Class 11 Biology ncert ppt
Bsc first year ppt
Bsc second year ppt
Bsc third year ppt
Science ppt
science project ppt
The slides contain all about meiosis. in this slides i collected all information about meiosis. which is useful for everyone.
so watch these slides and comment for any problems.
thanks
This presentation explains the topic of CELL CYCLE and CELL DIVISION.
It includes cell mitosis of both Plant cell and Animal cell with labelled diagrams.
Human digestive system structure and function
overview
Major organs
Mouth
Esophagus
Stomach
small intestine
large intestine
Acessory organs:
Liver
gall bladder
Pancreas.
Human digestive system
Major organs
Mouth
Esophagus
Stomach
small intestine
large intestine.
Acessory organs:
Liver
Gall bladder
Pancreas.
MAJOR ORGANSThe Mouth
pH: 7
The first part of the digestive system
the entry point of food.
Structures in the mouth that aids digestion
Teeth – cut, tear, crush and grind food.
Salivary glands – produce and secrete saliva into the oral cavity.
saliva
moistens the food
contains enzymes (ptyalin or salivary amylase)
begins digestion of starch into smaller polysaccharides.
Function:
Mechanical digestion.
increasing surface area for faster chemical digestion.
The Esophagus
a tube connecting the mouth to the stomach
running through the Thoracic cavity.
Location:
lies behind windpipe (Trachea).
The trachea has as an epiglottis
preventing food from entering the windpipe,
moving the food to the esophagus while swallowing.
Food travels down the esophagus, through a series of involuntary rhythmic contractions (wave-like) called peristalsis.
Function:
The lining of the esophagus secretes mucus
lubricating
to support the movement of food.
Esophageal sphincter:
bolus reaches the stomach
must pass through a muscular ringed valve called the esophageal sphincter (Cardiac Sphincter).
Function:
prevent stomach acids from back flowing into the esophagus.
Stomach
J-shaped muscular sac
Has inner folds (rugae)
Increasing surface area of the stomach.
Function:
Stomach performs mechanical digestion
HOW By churning the bolus and mixing it with the gastric juices
secreted by the lining of the stomach.
GASTRIC JUICES HCl, salts, enzymes, water and mucus)
HCL helps break down of food and kills bacteria that came along with the food.
The bolus is now called Chyme.
Enzymes in stomach:
Acidic environment
HCl secreation
kill any microbes that are found in the bolus,
creating a pH of 2.
Mucus prevents the stomach from digesting itself.
Pepsin secreation
responsible for initiating the breakdown of proteins (in )food.
hydrolyzes proteins to yield polypeptides.
pH is 2, the enzyme from the salivary glands stops breaking down carbohydrates.
Pyloric sphincter:
chyme moves from the stomach to the small intestine.
It passes through a muscular ringed sphincter called the pyloric sphincter.
stomach does not digest itselfWhy ?
Protective Mechanism:
three protective mechanisms.
First the stomach only secretes small amounts of gastric juices until food is present.
Second the secretion of mucus coats the lining of the stomach protecting it from the gastric juices.
The third mechanism is the digestive enzyme pepsin is secreted in an inactive protein c
Cells and its components(Anatomy) Easy explanationSwatilekha Das
Cells and its components,discussion on cell membrane, cytoplasm, nucleus with pictures....
easy explanation of anatomy topic for 1 st year GNM & B.Sc nursing students...
Comment to get explanation on your required topics.....
please like and share and follow.....
The cell is the basic structural, functional, and biological unit of all known organisms. A cell is the smallest unit of life. Cells are often called the "building blocks of life". The study of cells is called cell biology, cellular biology, or cytology.
Meiosis and Cell Cycle Stages ppt
Cell Cycle ppt
Cell Division ppt
Meiosis ppt
Stages of Meiosis ppt
Meiosis-I ppt
Stages of Meiosis-I ppt
Homologous Chromosomes ppt
Crossing Over ppt
Meiosis-I ppt
Stages of Meiosis-I ppt
Class 11 Biology ncert ppt
Bsc first year ppt
Bsc second year ppt
Bsc third year ppt
Science ppt
science project ppt
Ques-1Part-a Mitosis it is a somatic cell division in an organi.pdfsutharbharat59
Ques-1:
Part-a: Mitosis: it is a somatic cell division in an organism & this division is useful to maintain
body growth
Part-b: Meiosis: it is the reproductive reduction cell division & it is useful to produce gametes for
fertilization finally to generate a mature embryo
Part-c: cytokinesis: It is defined as the process of division of cytoplasm during cell division
either in mitosis or meiosis & this is useful for carrying cell organelles
Part-d: chromosome: it is the hereditary material that carries genomic information for gene
expression & useful for inheritance of parental traits to offspring
Mitosis ---> somatic cell division & produces two identical daughter cells with equal number of
chromosomes (cytokinesis & karyokinesis).
Meiosis ----> a reduction division occurs in reproductive germ cells in which allosomes
determine sex determination finally generates half of the chromosomes in daughter cells
Part-a: Mitosis: it is a somatic cell division in an organism & this division is useful to maintain
body growth
Part-b: Meiosis: it is the reproductive reduction cell division & it is useful to produce gametes for
fertilization finally to generate a mature embryo
Part-c: cytokinesis: It is defined as the process of division of cytoplasm during cell division
either in mitosis or meiosis & this is useful for carrying cell organelles
Part-d: chromosome: it is the hereditary material that carries genomic information for gene
expression & useful for inheritance of parental traits to offspring
Cell plate is absent during animal cell division instead a complete cleavage of the cells during
division can be observed in animal cells. Cell plate formation during cell division observed only
in plants.
Haploid cells (n) are normally produced by reduction division of meiosis from diploid parent
cells (2n). This type of division occurs in germ cells of male and female species. The
chromosomes of the diploid germ cell undergo reduction in meiosis I and generate half of the
chromosomes when compared to parent diploid cell.
Meiosis division in a reproductive cell often results in four haploid cells with only single set of
chromosomes.
Meiosis-I prophase-I In this process double stranded homologous chromosomes line up each
other, and result in forming a tetrad; this is termed as Synapsis.
Terminal chaismata hold the homologous chromosomes together in metaphase I finally these are
going to align on the metaphase plate. Synapsis allows homologous chromosomes to travel to the
center by forming spindle formation through microtubules attaching to the centromeres finally to
the opposite poles of the cell. Later, crossing over takes place to exchanges paternal and maternal
genes to form tetrad where genetic variation occurs. Crossing over takes place to exchange equal
amounts of DNA generates genetic variability in prophase -I of meiosis.
Crossing over occurs in which lined up chromosomal ends exchange genetic information by
switching their places. Crossing over can un.
The study of the cell cycle focuses on mechanisms that regulate the timing and frequency of DNA duplication and cell division. As a biological concept, the cell cycle is defined as the period between successive divisions of a cell. During this period, the contents of the cell must be accurately replicated.
The cell cycle is regulated by cyclins and cyclin-dependent kinases.
How long is one cell cycle?
Depends. Eg. Skin cells every 24 hours. Some bacteria every 2 hours. Some cells every 3 months. Cancer cells very short. Nerve cells never.
Programmed cell death:
Each cell type will only do so many cell cycles then die. (Apoptosis)
Science teaching is a complex activity that lies at the heart of the vision of science education presented in the Standards. The teaching standards provide criteria for making judgments about progress toward the vision; they describe what teachers of science at all grade levels should understand and be able to do.
Life of every organism depends on certain basic processes. Excretion is one among them. Different organisms follow different modes of excretion. In complex organisms including humans, there is a specialized system for excretion called human excretory system.
The primitive blueprint for the heart and circulatory system emerged with the arrival of the third mesodermal germ layer in bilaterians. Since then, hearts in animals have evolved from a single layered tube to a multiple chambered heart in due course of time.
Cell Signaling is a phenomenon in which cells receive and respond to the signals or chemical messages from their internal environment or from the neighbouring cells.
Flight in bird is one of the most complex forms of locomotion in the animal kingdom. Flight in birds includes hovering, taking off and landing which involves many complex movements.
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
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at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
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Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
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Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
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2. Defination: Cell division is the process by
which a parent cell divides into two or more
daughter cells. Cell division usually occurs as
part of a larger cell cycle
In cell division, the cell that is dividing is called
the "parent" cell. The parent cell divides into two
"daughter" cells and the process then repeats in
what is called the cell cycle.
2
3. Why Do Cells Divide?
Cells divide basically for three reasons. They are:
a) For the growth & development of our body
b) To repair the dead and damaged tissues
c) For reproduction
3
4. The cells of higher organisms divide by two
processes. They are :
1) Mitosis: The process that cells use to make
exact replicas of themselves is mitosis. Mitosis is
observed in almost all the body’s cells, including
eyes, skin, hair and muscle cells.
2) Meiosis: In this type of cell division, sperm or
egg cells are produced with haploid set of
chromosomes instead of identical daughter cells
as in mitosis.
4
6. Cell Cycle
During the cell cycle,
– Cell grows.
– DNA is replicated.
– Mitotic cell division produces daughter cell
identical to the parent.
There are two primary phases in the cell cycle:
Interphase: This phase was thought to represent the resting stage
between subsequent cell divisions, but new research has shown that it
is a very active phase.
M Phase (Mitosis phase): This is where the actual cell division occurs.
There are two key steps in this phase, namely cytokinesis and
karyokinesis.
6
7. The interphase comprises three phases:
G0 Phase (Resting Phase): The cell neither divides nor
prepares itself for the division.
G1 Phase (Gap 1): The cell is metabolically active and
grows continuously during this phase.
S phase (Synthesis): The DNA replication or synthesis
occurs during this stage.
G2 phase (Gap 2): Protein synthesis happens in this phase.
Quiescent Stage (G0): The cells that do not undergo further division
exits the G1 phase and enters an inactive stage. This stage is known
as the quiescent stage (G0) of the cell cycle.
Interphase
7
8. Interphase
It is actually a Non-dividing state.
In this state….
– cell grows in size
– organelles replicated
– replication of DNA
– synthesis of proteins
associated with DNA
– synthesis of proteins
associated with mitosis
8
9. Division of somatic cells in eukaryotic organisms is
called as mitosis
In this process, a single cell divides into two identical
daughter cells.
Daughter cells have same set of chromosomes as does
the parent cell.
Mitosis Cell Division
9
10. Mitosis
It has 4 sub-phases:
1st – Prophase
2nd – Metaphase
3rd – Anaphase
4th – Telophase
followed by
Cytokinesis
10
11. 1. Prophase
In Prophase 3 Major
Events take place.
1) Chromosomes condense
2) Spindle fibers form
(spindle fibers are specialized microtubules
radiating out from centrioles)
3) Chromosomes are
captured by spindle
11
13. In this phase chromosomes align
along equator of the cell, with one
kinetochore facing each pole
centrioles
spindle fibers
chromosomes
2. Metaphase
Kinetocores not pictured in this illustration.
13
14. 3. Anaphase
In anaphase stage the
sister chromatids separate
from each other.
Spindle fibers attached to
kinetochores shorten and
pull the chromatids towards
the opposite poles.
The cell appears almost oval
in shape as it starts becoming
longer.
14
15. 4. Telophase
•In the telophase stage, the spindle fibers
between the poles disintegrate.
•The nuclear envelopes start reforming around
both the groups of chromosomes at the poles
•Chromosomes revert to their extended state by
absorbing water from the cytoplasm
•There appears a constriction in the cytoplasm
between the two groups of dividing chromosomes
* Cytokinesis completes the enclosing of each
daughter nucleus into a separate cell
15
16. CYTOKINESIS – IN ANIMAL CELL
.
Cytokinesis is the last phase of the
normal cell cycle. In this phase the
cell physically divides into two
identical daughter cells. In animal
cells, the cell membrane pinches
together and the membrane breaks
apart where it was pinched and now
it is two daughter cells. In both new
cells the DNA is identical. In plant
cells, a cell plate forms down the
middle of the cell and the cell
breaks apart where the cell plate
was formed. The two daughter cells
will often stay attached to each
other side-by-side
16
17. REDUCTION CELL DIVISION
Meiosis is a process
where a single cell divides
twice to produce four
daughter cells containing
half the original amount of
genetic information.
These cells are called as
gamates sperm in males,
eggs in females.
17
18. Diploid organisms receive one of each type of
chromosome from female parent and one of each
type of chromosome from male
Ploidy refers to the number of sets
of chromosomes in cells.
● Haploid : * It contains only one copy of chromosome
* It is designated as “n”
● Diploid : * It contains two sets of chromosomes
* It is designated as “2n”
Genetics Terminology: Ploidy
18
19. GENETICS TERMINOLOGY: HOMOLOGUES
Chromosomes exist in homologous pairs
in all diploid (2n) cells except in Sex Chromosomes in male (XY)
Apart from the Sex chromosomes, the other chromosomes
are known as autosomes and all they have homologues.
19
20. MEIOSIS – THE GAMETE FORMATION
In meiosis, there are 2
nuclear divisions.
They are
Meiosis I
&
Meiosis II
20
21. MEIOSIS - I
Meiosis is a reduction division. The salient features of meiotic
division that make it different from mitosis are as follows:-
1) It occurs in two stages of the nuclear and cellular division
as Meiosis I and Meiosis II. DNA replication occurs,
however, only once.
2) It involves the pairing of homologous chromosomes and
recombination between them.
3) Four haploid daughter cells are produced at the end,
unlike two diploid daughter cells in mitosis.
21
22. Meiosis-I
has following
four sub stages :
Prophase - I
Metaphase - I
Anaphase - I
Telophase - I
Prophase - I
Prophase - I is longer than the
mitotic prophase and is further
subdivided into 5 sub stages.
They are :
Leptotene
Zygotene
Pachytene
Diplotene
Diakinesis
22
23. LEPTOTENE
Leptotene is the first of five stages of Prophase - I and it
consists of the condensation of the already replicated
chromosomes
The chromosomes become visible and now they can be
distinguished easily.
The chromosomes at this stage are likened to a string
with beads, called chromomeres.
Each sister chromatid is attached to the nuclear envelope
and they are so close together that they can be mistaken
as one chromosome.
23
25. ZYGOTENE
In this stage the homologous chromosomes begin to pair.
This process is also known as zygonema (Synapsis).
These synapsis can form along the entire length of the
chromosomes allowing numerous points of contact called
'synaptonemal complex‘.
The synaptonemal complex facilitates synapsis by holding
the chromosomes together. along the entire length.
After the homologous pairs synapse they are either
called bivalents.
25
27. PACHYTENE
Once the synapse is formed, now the cell is ready
for crossing over.
In this stage further thickening and shortening of
chromosomes take place.
During this stage, exchanges of chromosome material
between maternal and paternal homologous
chromosomes occur by crossing over.
At the points of crossing over, X–shaped chiasmata are
seen in variable numbers.
27
29. DIPLOTENE
In the "Diplotene" stage, the paired chromosomes begin
to get separated from each other.
While getting separated, the homologous chromosomes
remain united at the points of interchange of "Chismata".
Chiasma are formed as the result of crossing over in the
Diplotene stage.
With the progression of diplotene, the nuclear membrane
gets disorganized and the nucleolus disappears.
29
31. In this stage, bivalents get distributed in the nucleus. The
nuclear membrane breaks down and the nucleolus
disappears.
Chiasma moves towards the end, and this process is
called as terminalization.
Chromatids remain attached only at the terminal
chiasmata and enter the metaphase stage.
Recondensation of chromosomes takes place. Tetrad
move towards equatorial metaphase plate and spindle
formation is initiated.
DIAKINESIS
31
33. METAPHASE - I
In Metaphase-I of meosis the maternal and paternal
chromosomes (homologous chromosomes) align along
the equator of the cell.
A process called independent assortment occurs where
the maternal and paternal chromosomes line up randomly
and align themselves on either side of the equator.
At this stage 50% of the chromosomes start migrating to
the opposite pole of the dividing cell.
33
35. ANAPHSE-I
In this stage Kinetochore microtubules shorten and pull
the homologous chromosomes to opposite poles.
The sister chromatids remain tightly bound together at the
centromere.
The chiasmata are broken in as the microtubules attached
to the fused kinetochores pull the homologous
chromosomes apart .
Non-kinetochore microtubules lengthen, pushing the
centrosomes farther apart and the cell starts elongatting.
35
37. TELOPHASE-I
This is the end of the First meiotic division.
Each daughter cell now has half the number of chromosomes
but each chromosome consists of a pair of chromatids.
The microtubules that make up the spindle network disappear,
and a new nuclear membrane surrounds each haploid set.
The chromosomes uncoil back into chromatin.
Cytokinesis occurs, completing the creation of two daughter
cells. However, cytokinesis does not fully complete resulting in
"cytoplasmic bridges" which enable the cytoplasm to be
shared between daughter cells until the end of meiosis II
37
39. MEIOSIS-II
Meiosis-II initiates immediately after cytokinesis, usually before the
chromosomes have fully decondensed.
In contrast to meiosis I, meiosis II resembles a normal mitosis. In some
species, cells enter a brief interphase, or interkinesis, before entering
meiosis II.
However this interphase lacks an S phase, so chromosomes are not
duplicated. The two cells produced in meiosis I go through the events of
meiosis II together.
During meiosis II, the sister chromatids within the two daughter cells
separate, forming four new haploid gametes. The mechanics of meiosis
II is similar to mitosis, except that each dividing cell has only one set of
homologous chromosomes.
39