Lecture 1

Question 1

What are the common features in the development of plant and animals

Answer 1

they both depend on:

1. ) cell growth and multiplication (cell expansion, cell division)
2. ) cell differentiation
3. ) morphogenesis

Question 2

Define cell expansion

Answer 2

cell enlargement

Question 3

Define cell division

Answer 3

increase in cell number

Question 4

Define cell differentiation

Answer 4

specialization of cells to acquire specific functions

Question 5

Define morphogenesis

Answer 5

creation of form

Question 6

What are the essential differences between the development of plant and animal cells

Answer 6

1. ) no cell migration in plants
   - rigid cell wall, fixed position
2. ) Ongoing growth & morphogenesis
   - at plant meristems
3. ) May be differences in permanence of differentiation; plants can change organs they make as time goes on; totipotent
4. ) plants and animals evolved multicellularity independently

Question 7

Define totipotent

Answer 7

having the ability to differentiate into all cell types

Question 8

What controls plant development

Answer 8

co-ordinated program of gene expression and cell signalling that regulates cell division and expansion, cell differentiation and morphogenesis

Question 9

true or false; plant body is laid down by cell growth and differentiation at meristem

Answer 9

true

Question 10

What abiotic factors affect plant growth

Answer 10

light 
temperature 
nutrients
drought
pests

Question 11

What are meristems

Answer 11

undifferentiated cells capable of cell division, but also of differentiation

Question 12

Where does the word meristem come from and what does it mean in that language

Answer 12

Greek
meristos
means divisible

Question 13

What are the 3 types of meristems

Answer 13

SAM ; shoot apical meristem
RAM; root apical meristem
Lateral meristems ( in woody plants)

Question 14

true or false; ongoing growth and morphogenesis at plant meristems

Answer 14

true

Question 15

What is the difference between vegetative shoot apical meristem and reproductive shoot apical meristem

Answer 15

vegetative apical meristem produces leaves

reproductive apical meristem produces flowers

Question 16

what are the three developmental shifts that a plant undergoes throughout their lifetime

Answer 16

juvenile
adult vegetative
adult reproductive

Question 17

Define apoptosis

Answer 17

programmed cell death

Question 18

true or false; mature xylem cells function as conducting vessels, but are dead as they have no cytoplasm or nucleus

Answer 18

true

Question 19

true or false; the symmetry of cell division is important

Answer 19

true

Question 20

why are asymmetric cell divisions important

Answer 20

crucial for establishing axial polarity (top and bottom of plant)

Question 21

what happens when incorrect asymmetric division occurs

Answer 21

mutant plants occur

Question 22

What is a gnom mutant

Answer 22

ball shaped

lacks leaves and roots

Question 23

plane a cell division does what

Answer 23

increased length

Question 24

plane b of cell division does what

Answer 24

increased girth

Question 25

plane c of cell division does what

Answer 25

cell into next row (cortex); inside the cell

Question 26

What are preprophase bands

Answer 26

bands of microtubules

- orientation of preprophase bands of microtubules determines the plane and symmetry of cell division

Question 27

What is the cell plate

Answer 27

where cell will divide

Question 28

What determines the direction of cell expansion (one direction)

Answer 28

controlled by the orientation of cellulose microfibrils in the cell wall

Question 29

What drives expansion

Answer 29

driven by turgor pressure of K+ ions into the cell; forces water inside the cell

Question 30

What are important for determining plant form

Answer 30

plane and symmetry of cell division

Question 31

what controls the orientation of the cellulose microfibrils in the wall

Answer 31

controlled by microtubules inside the cell

Question 32

what are ‘left’ mutants of Arapidopsis

Answer 32

have altered cellulose microfibril angles

Question 33

Why do ‘lefty’ arabidopsis mutants occur

Answer 33

have amino acid changes in the tubulin gene (tubulin makes the microtubules)

Question 34

What do the microtubules control

Answer 34

• control plane of cell division

- direction of cell enlargement

Question 35

What does it mean by leaf primordium

Answer 35

the first trace of an organ

Question 36

What happens when growth of leaf primordium is unregulated

Answer 36

doesn’t make a leaf, it makes an undifferentiated tissue called CALLUS

Question 37

what determines the size and shape of a leaf

Answer 37

differential growth:

• total number of cell division cycles (more cells meaning more leaves)
• relative orientation and distribution of cell divisions and cell expansions
• relative timing of cell cycle arrest