Basic attributes
common to many forms of life
 Cellular structure and intracellular
compartmentalization; and
Metabolism...
A After a corn grain (seed) germinates, its
radicle and coleoptile emerge. The radicle
develops into the primary root. The...
Early Growth of a Bean
(Eudicot)
Fig. 31-4a, p. 525
seed
coat radicle
cotyledons (two)
hypocotyl
primary root
A After a bean seed germinates, its radicle e...
Fig. 31-4b, p. 525
primary
leaf
primary
leaf
withered
cotyledon
branch root
primary root
root nodule
B Photosynthetic cell...
Fig. 31-22, p. 535
germination
mature
sporophyte
(2n)
zygote
in seed (2n)
fertilization
meiosis
in anther
meiosis
in ovary...
Plant Development
• Plant development includes seed
germination and all events of the life cycle,
such as root and shoot d...
Pollination and fertilization
Development- process – complex,
multicellular organism arises from a single
cell, a gradual process, so the complexity
of ...
Development- process by which an
organism changes to acquire new
structures and abilities. It occurs in
response to variou...
gametes
zygote
Differentiation Pattern
formation
MorphogenesisCell
division
Growth
Diversification
of cell types
Organizat...
Growth
: increase of size and weight,.
Diameter, height, volume and weight can
be measured.
 Biochemical properties can...
After imbibition of water by
seeds, the growth by which
the embryo becomes a young
seedling occurs by both
expansion of ce...
gametes
zygote
Differentiation Pattern
formation
MorphogenesisCell
division
Growth
Diversification
of cell types
Organizat...
Cell division
The plane in which a cell divides is
determined during late interphase.
First sign of this spatial
orientation is rearrang...
Fig. 35-25
of
ivision
s of cell division
Developing
guard cells
Guard cell
“mother cell”
ecialized
rmal cell
etrical cell ...
PLANES OF DIVISION VARY AS DEVELOPMENT OF CALLUS
Cell expansion contributes to plant form.
Orientation of cell growth is in the plane
perpendicular to the orientation of t...
The orientation of cellulose microfibrils (CMFs) is
a determining factor in cell growth. Elongation is
favored when CMFs a...
Auxins in cell expansion
ENZYME THAT BREAKS CROSS LINKS
OR HYDROGEN BONDS BETWEEN
CELLULOSE MICROFIBRILS
gametes
zygote
Differentiation Pattern
formation
MorphogenesisCell
division
Growth
Diversification
of cell types
Organizat...
Cell Differentiation
Cells become specialized in structure
and function. A fertilized egg gives rise
to many different kin...
Gene expression
Cells must continually turn genes on and off
in response to signals from external and
internal environmen...
DNA
Primary RNA
transcript
protein
inactive mRNA
Inactive protein
mRNA degradation
control
Translational control
by riboso...
Each stage is a
potential
control point at
which gene
expression can
be turned on or
off, accelerated
or slowed down.
In a...
gametes
zygote
Differentiation Pattern
formation
MorphogenesisCell
division
Growth
Diversification
of cell types
Organizat...
Pattern structure
Form –one of outstanding characteristics of living
organisms.
Though complex,various parts bear predic...
O X O
O X O
O X O
The distribution of the specialized cell is not
random since the location of any given cell is at
least ...
O X O
X
X O
O X
O X O
O X O
O X O
A
B
X O
X O
X O
X O
X X
X X O O
X x O O
O O
C
D
random
Non-random
Non-random
Non-random
Pattern formation-
 Development of a spatial organization in which the tissues and
organs are all in their characteristic...
Pattern formation
First patterning event in the embryo- axis
specification. This reflects asymmetric
division of the zygot...
Arrangement
of leaves
Leaf primordia flanking the apical meristem
Development of
zygote into an
embryo
Organ expansion and maturation
Globular-heart transition
Embryogenesis
X-section of a young root Epidermal tissue
Morphogenesis- creation of form
Physical process that give an organism its shape
in each cell type
The different kinds o...
In animals,
morphogenesis
– many involve
movement of
cells relative to
other cells
In plants, cells have cell walls
and mi...
Planes of cell division determine shape of
particular tissues.
Terms to describe planes of cell division:
anticlinal – SUR...
Model organisms
Uses:
• to gain comprehensive knowledge about a
complete plant.
• to further detailed understanding of
mec...
Arabidopsis thaliana
Small, ca 30 cm tall, with flat
rossette of leaves.
Arabidopsis thaliana (wall cress)
Small, less than 30 cm
Life cycle-about 6-8 weeks, hermaphrodite
flowers, self-fertiliz...
2n=10, have 26,700 protein-encoding
genes but many are duplicates, ca 15,000
different types of genes,
It has one of the...
Transgenic plants can be made easily using Agrobacterium
tumefaciens as the vector to introduce foreign genes.
Mutations ...
Aim is to to establish a
blueprint for how plants
develop
inflorescences
• 2n=20, 10 large chromosome pairs
•Large no of progeny per cross ca 100 to 200 )
•Facilitated discovery of...
Levels of developmental control
1. Genetic and intracellular control of
development.
An individual mature cell in the veg...
Transplantation
experiments in
Acetabularia
mediterranea and
A. crenulata
Shows importance
of nucleus
for cell
differentia...
Flow of genetic information
Fig. 14-4, p. 218
Stepped Art
DNA template
New DNA strand
DNA template
RNA transcript
Transcription
Genetic Information
• From DNA to mRNA to amino acid
sequence
Levels of developmental control
2. Hormonal and intercellular control of
development
A hormone may act by altering gene
e...
Lack abscissic acid
MAIN Factor that affects
color is soil pH.
Acidic= pink/red flowers
Alkaline= blue flowers
Environmental factors
Etiolated shoot in potato –developing in the absence of light, turn
green upon exposure to light. The plant is able to det...
Dev bio first lecture ppt 1
Dev bio first lecture ppt 1
Dev bio first lecture ppt 1
Dev bio first lecture ppt 1
Dev bio first lecture ppt 1
Dev bio first lecture ppt 1
Dev bio first lecture ppt 1
Dev bio first lecture ppt 1
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  • Figure 31.3 Early growth of corn ( Zea mays ), a monocot.
  • Figure 31.4 Early growth of the common bean plant ( Phaseolus vulgaris ), a eudicot.
  • Figure 31.4 Early growth of the common bean plant ( Phaseolus vulgaris ), a eudicot.
  • Figure 31.22 Summary of development in the life cycle of a typical eudicot.
  • Figure 14.4 Base pairing during ( a ) DNA synthesis and ( b ) transcription.
  • Dev bio first lecture ppt 1

    1. 1. Basic attributes common to many forms of life  Cellular structure and intracellular compartmentalization; and Metabolism and transfer of energy Storage and transmission of genetic information Reproduction  Development- each individual will go through certain changes of form and function during its life
    2. 2. A After a corn grain (seed) germinates, its radicle and coleoptile emerge. The radicle develops into the primary root. The coleoptile grows upward and opens a channel through the soil to the surface, B The plumule develops into the seedling’s primary shoot, which pushes through the coleoptile and begins photosynthesis. In corn plants, adventitious roots that develop from the stem afford additional support for the rapidly growing plant. Fig. 31-3, p. 525 Stepped Art hypocotyl radicle branch root branch root primary root primary root adventitious (prop) root primary leaf coleoptile coleoptile coleoptile
    3. 3. Early Growth of a Bean (Eudicot)
    4. 4. Fig. 31-4a, p. 525 seed coat radicle cotyledons (two) hypocotyl primary root A After a bean seed germinates, its radicle emerges and bends in the shape of a hook. Sunlight causes the hypocotyl to straighten, which pulls the cotyledons up through the soil.
    5. 5. Fig. 31-4b, p. 525 primary leaf primary leaf withered cotyledon branch root primary root root nodule B Photosynthetic cells in the cotyledons make food for several days, then the seedling’s leaves take over the task. The cotyledons wither and fall off.
    6. 6. Fig. 31-22, p. 535 germination mature sporophyte (2n) zygote in seed (2n) fertilization meiosis in anther meiosis in ovary DIPLOID HAPLOID microspores (n) megaspores (n) eggs (n) sperm (n) male gametophyte (n) female gametophyte (n)
    7. 7. Plant Development • Plant development includes seed germination and all events of the life cycle, such as root and shoot development, flowering, fruit formation, and dormancy • These activities have a genetic basis, but are also influenced by environmental factors
    8. 8. Pollination and fertilization
    9. 9. Development- process – complex, multicellular organism arises from a single cell, a gradual process, so the complexity of the embryo increases progressively. Development –progressive-i.e. a simple embryo with few cell types organized in a crude pattern gradually refined to generate a complex organism with many cell types showing highly detailed organization.
    10. 10. Development- process by which an organism changes to acquire new structures and abilities. It occurs in response to various levels of control: 1. Genetic instructions 2. Intercellular interaction 3. Environmental factors
    11. 11. gametes zygote Differentiation Pattern formation MorphogenesisCell division Growth Diversification of cell types OrganizationGeneration of shapes & structures Increase in cell number Increase in size Adult Gametes Major overlapping processes
    12. 12. Growth : increase of size and weight,. Diameter, height, volume and weight can be measured.  Biochemical properties can also be established: Enzyme activity, pigment content, protein content, DNA and RNA content may be used to characterize the organism. Single cells show 2 major components of growth: division and enlargement
    13. 13. After imbibition of water by seeds, the growth by which the embryo becomes a young seedling occurs by both expansion of cells originally present in the dormant embryo and mitotic divisions resulting in an increase in cell number
    14. 14. gametes zygote Differentiation Pattern formation MorphogenesisCell division Growth Diversification of cell types OrganizationGeneration of shapes & structures Increase in cell number Increase in size Adult Gametes Major overlapping processes
    15. 15. Cell division
    16. 16. The plane in which a cell divides is determined during late interphase. First sign of this spatial orientation is rearrangement of the cytoskeleton In the cytoplasm into a ring called pre-prophase band. Band disappears before metaphase but it predicts the future plane of division. It predicts where the cell plate will be inserted (the division site). The “imprint” consist of actin microfilaments that remain after microtubules disperse.
    17. 17. Fig. 35-25 of ivision s of cell division Developing guard cells Guard cell “mother cell” ecialized rmal cell etrical cell division If planes of division of the descendants are parallel to the plane of the ist cell division, single file of cells results. Cell division in 3 planes gives rise to a cube. If planes vary randomly, will be a disorganized clump. Guard cells form perpendicular to the first division
    18. 18. PLANES OF DIVISION VARY AS DEVELOPMENT OF CALLUS
    19. 19. Cell expansion contributes to plant form. Orientation of cell growth is in the plane perpendicular to the orientation of the cellulose microfibrils in the wall. Enzymes weaken cross- links in the wall, and allow it to expand as water diffuses into vacuole by osmosis.
    20. 20. The orientation of cellulose microfibrils (CMFs) is a determining factor in cell growth. Elongation is favored when CMFs are oriented transversely to the direction of growth while elongation is limited when CMFs are oriented in the oblique or longitudinal direction. Orientation of cellulose microfibrils in growth- cell expansion. CA 80 CELLULOSE IN A MICROFIBRIL
    21. 21. Auxins in cell expansion ENZYME THAT BREAKS CROSS LINKS OR HYDROGEN BONDS BETWEEN CELLULOSE MICROFIBRILS
    22. 22. gametes zygote Differentiation Pattern formation MorphogenesisCell division Growth Diversification of cell types OrganizationGeneration of shapes & structures Increase in cell number Increase in size Adult Gametes Major overlapping processes
    23. 23. Cell Differentiation Cells become specialized in structure and function. A fertilized egg gives rise to many different kinds of cells, each with a different structure and function. A program of differential gene expression (the expression of different sets of genes by cells with the same genome) leads to the different cell types in a multicellular organism
    24. 24. Gene expression Cells must continually turn genes on and off in response to signals from external and internal environment. Regulation of gene expression is necessary for cell specialization in multicellular organisms. The differences between cell types are not due to different genes being present but to differential gene expression, the expression of different sets of genes by cells with the same genome
    25. 25. DNA Primary RNA transcript protein inactive mRNA Inactive protein mRNA degradation control Translational control by ribosome selection among mRNAs Protein activity control Transcriptional control 1 2 Processing control 3 Transport control mRNA mRNA 6 4 5 Steps at which gene expression can be controlled in eukaryotes NUCLEUS CYTOPLASM
    26. 26. Each stage is a potential control point at which gene expression can be turned on or off, accelerated or slowed down. In all organisms, a common control point for gene expression is at transcription . In this stage regulation is often in response to signals coming from outside cell e.g. hormones or other signaling molecules.
    27. 27. gametes zygote Differentiation Pattern formation MorphogenesisCell division Growth Diversification of cell types OrganizationGeneration of shapes & structures Increase in cell number Increase in size Adult Gametes Major overlapping processes
    28. 28. Pattern structure Form –one of outstanding characteristics of living organisms. Though complex,various parts bear predictable, repeated relations to one another. Regularity or deviation from random distribution of various parts of cells or tissues
    29. 29. O X O O X O O X O The distribution of the specialized cell is not random since the location of any given cell is at least predictable from the location of other cells B X O X O X O X O X X X X O O X x O O O O C D Non-random Non-random Non-random
    30. 30. O X O X X O O X O X O O X O O X O A B X O X O X O X O X X X X O O X x O O O O C D random Non-random Non-random Non-random
    31. 31. Pattern formation-  Development of a spatial organization in which the tissues and organs are all in their characteristic places.  It is the development of specific structures in specific locations. Cells must be organized into multicellular arrangements of tissue and organs.  Pattern formation is determined by positional information in the form of signals that continuously indicate to each cell its location within a developing structure  Each cell within a developing organ responds to positional information from neighbouring cells by differentiating into a particular cell type, oriented in a particular way. - gradients of specific molecules - hormones, proteins -mRNA provide positional information
    32. 32. Pattern formation First patterning event in the embryo- axis specification. This reflects asymmetric division of the zygote: apical cell basal cell Establishment of the principal body axis --ANTEROPOSTERIOR --DORSOVENTRAL embryo Suspensor filament
    33. 33. Arrangement of leaves
    34. 34. Leaf primordia flanking the apical meristem
    35. 35. Development of zygote into an embryo
    36. 36. Organ expansion and maturation Globular-heart transition Embryogenesis
    37. 37. X-section of a young root Epidermal tissue
    38. 38. Morphogenesis- creation of form Physical process that give an organism its shape in each cell type The different kinds of cells not randomly distributed but organized into tissues and organs in a particular three- dimensional arrangement. Reflects different aspects of cell structure and behavior including: cell division, cell shape and size, interaction between cells , and cell death.
    39. 39. In animals, morphogenesis – many involve movement of cells relative to other cells In plants, cells have cell walls and middle lamella which tightly cement cells together. No relative cell movement or migration. Morphogenesis reflects a restricted set of processes- such as: 1.differential rates and planes of cell division 2. changes in cell size due to the increasing volume of the vacuole.
    40. 40. Planes of cell division determine shape of particular tissues. Terms to describe planes of cell division: anticlinal – SURFACE GROWTH. occur in the plane of the sheet- expands the sheet WITHOUT INCREASING THE THICKNESS. periclinal- occur at right angles to the plane of a sheet so results in its expansion into multiple layers. Switching from anticlinal to periclinal cell division is critical for some morphogenetic processes, e.g. outgrowth of leaves.
    41. 41. Model organisms Uses: • to gain comprehensive knowledge about a complete plant. • to further detailed understanding of mechanisms and processes in plants. • to understand particular biological phenomena with the expectation that discoveries made on the model organism will provide insight into the workings of other organisms Select model organism that lend themselves to study of a particular group and are representative of a larger group.
    42. 42. Arabidopsis thaliana Small, ca 30 cm tall, with flat rossette of leaves.
    43. 43. Arabidopsis thaliana (wall cress) Small, less than 30 cm Life cycle-about 6-8 weeks, hermaphrodite flowers, self-fertilizing flowers. Easy to grow large numbers in the lab. Under continuous light 25 degrees centigrade, up to 10,000 to 50,000 seeds. Plants can grow to form ripe seeds within 8 weeks A single flower can produce 30-50 seeds. Whole plant can produce several thousands, up to 10,000 seeds per plant making study of genetics easier. Ideal for isolating mutants and for genetic
    44. 44. 2n=10, have 26,700 protein-encoding genes but many are duplicates, ca 15,000 different types of genes, It has one of the smallest genomes in the plant kingdom: 115,409,949 base pairs of DNA distributed in 5 chromosomes (2n = 10). Very little "junk" DNA
    45. 45. Transgenic plants can be made easily using Agrobacterium tumefaciens as the vector to introduce foreign genes. Mutations can be easily generated (e.g., by irradiating the seeds or treating them with mutagenic chemicals). It is normally self-pollinated so recessive mutations quickly become homozygous and is expressed
    46. 46. Aim is to to establish a blueprint for how plants develop
    47. 47. inflorescences • 2n=20, 10 large chromosome pairs •Large no of progeny per cross ca 100 to 200 ) •Facilitated discovery of transposons (jumping genes)-mobile genetic elements that disrupt the functions of some genes.
    48. 48. Levels of developmental control 1. Genetic and intracellular control of development. An individual mature cell in the vegetative body of the plant retains within nucleus all the genetic information to reproduce the dev. steps necessary to form the whole organism. Genetic constitution is expressed in terms of the biochemical events within the cell which lead to specific cell differentiation at specific times.
    49. 49. Transplantation experiments in Acetabularia mediterranea and A. crenulata Shows importance of nucleus for cell differentiation Morphogenesis of the cap is dependent upon species-specific RNA molecules translated into proteins
    50. 50. Flow of genetic information
    51. 51. Fig. 14-4, p. 218 Stepped Art DNA template New DNA strand DNA template RNA transcript Transcription
    52. 52. Genetic Information • From DNA to mRNA to amino acid sequence
    53. 53. Levels of developmental control 2. Hormonal and intercellular control of development A hormone may act by altering gene expression affect activity of existing enzymes changing properties of membrane Any of the above could redirect the metabolism and development of a cell responding to small number of molecules
    54. 54. Lack abscissic acid
    55. 55. MAIN Factor that affects color is soil pH. Acidic= pink/red flowers Alkaline= blue flowers Environmental factors
    56. 56. Etiolated shoot in potato –developing in the absence of light, turn green upon exposure to light. The plant is able to detect the light intensity and wavelength by using photoreceptors , but receptor does not interact directly with the cell’s DNA but a signal transduction chain is involved:phytochrome, blue light/UV-A and UV-B receptors .

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