Plant R+D+G

Question 1

unlike animal development plants dont undergo

Answer 1

cleavage or gastrulation

Question 2

describe the process of cell division in plants

Answer 2

microtubules align themselves in a paticular orientation

nucleus moves to the middle

cell division occurs

cell plate is formed

preprophase band dictates where the cell plate is formed

Question 3

how is the 3 dimensinal plant form determined

Answer 3

depends on the orientation and growth rate of the current cells

Question 4

4 stages of development in a plant

Answer 4

early globular - epidermis starts to form
late globular
heart stage
torpedo stage - group of cells get set apart to become stem cells

Question 5

what are the two groups of meristem?

Answer 5

shoot apical meristem - stem cells are produced for the shoot

root apical meristem - root cells are produced

Question 6

the meristem can be described as a ________

Answer 6

strucutre pattern generating machine

Question 7

how do cells know where they are within a plant

Answer 7

interpret the concentration of a morphogen which changes down a gradient = french flag model

Question 8

describe why without pin proteins auxin would be trapped in plant cells

Answer 8

IAA (auxin) can be protonated (IAAH) or deprotonated (IAA-)
at normal pH of around 7.2 in the cytoplasm IAA- is favoured

charged molecules cant move across membranes

Question 9

describe the action of pin proteins

Answer 9

can transport auxin across membranes

• into cell wall and into matrix where pH is 5 IAA- becomes IAAH
• auxin import proteins are involved

move into neighbouting cells where pH is 7.2 again hence is deprotonated

Question 10

new vascular tissue forms where morphogen level is _____.

Answer 10

high

Question 11

where are pin proteins formed?

Answer 11

nextdoor to high auxin concentration cells

Question 12

how is auxin promoted growth self limiting

Answer 12

the growth of an area means the concentration of auxin across that area reduces

Question 13

what pattern of growth is found to be most common in plants

Answer 13

spiral

Question 14

where is the primary and secondary mersitems in root

Answer 14

primary at the bottom

pericycle secondary meristem

Question 15

plant development depends on the distribution of ___________ . which are generated by _____ _____ meristems

Answer 15

secondary meristems

primary apical

Question 16

axilary meristems have cells arrested in ___

Answer 16

G0

Question 17

what type of meristems lie within the stem

Answer 17

lateral

Question 18

what two areas of the stem do stem cells lie in?

Answer 18

vascular cambium - grow and divide for a huge amount of time

corck cambium - generates the tough outer part

Question 19

what can the meristems in the pericycle form

Answer 19

new lateral roots whic allow the plant to explore its environment

Question 20

name a plant that forms budlets from stem cells

Answer 20

kalanchoe

Question 21

where female gametes found iin angiosperms

Answer 21

carpel

Question 22

male part of an angiosperm is the

Answer 22

stamen

Question 23

describe the ABC model of flower formation

Answer 23

three gene domains A B and C
where only A is expressed you get a sepeal
where only C is expressed you have carpel

A and B gives a petal
B and C gives a stamen

Question 24

which transcription factor is required to switch the meristem from making leaves to making a flower. when is it activated?

Answer 24

leafy

signalling between different parts of the organism followed by complex signalling within a tissue

Question 25

what process occurs in male plants to form microspores and where. then what process forms the sperm nuclei

Answer 25

meiosis sporangium mitosis to forms sperm nuclei

Question 26

describe the process of making female gametes in angiosperms

Answer 26

``` megaspore undergoes meiosis - 4 daughter cells - 3 die - 1 haploid cell = mega spore then each haploid cell undergoes mitosis to have two nuclei ``` egg cell and polar nuclei are formed

Question 27

describe the double fertilisation event that occurs in angisperms

Answer 27

pollen generates two sperm nuclei 1 sperm nucleus fuses with the two polar nuclei - triploid endosperm formation 1 sperm nucleus fuses with the egg - diploid zygote formation

Question 28

what is important about the endosperm

Answer 28

most grains come from endosperm

Question 29

what hormmone is activated in seeds to start growth?

Answer 29

alpha amylase

Question 30

how do plants avoid asexual reproduction?

Answer 30

carpel and stamen may mature at different times self incompatibiity factors = genotypes on pollen that block germination if they are the same as that of the carpel

Question 31

where is the embryo kept?

Answer 31

within the seed

Question 32

what triggers seed germination?

Answer 32

environmental factors | uptake of water leading to activation of metabolism

Question 33

lots of cell division occurs at the bottom of the root but there is limited ______. where as there is in the zone of elongation there is vey little division but lots of _______

Answer 33

growth | growth

Question 34

what is the internal hydrostatic pressure of the vacuole called?

Answer 34

turgor

Question 35

describe the structure of the plant cell wall

Answer 35

cellulose - long unbranced glucose polymer is connected to pectin - glucorminc acid based polymer linked together by hemicellulose

Question 36

cellulose provides high ______ strength to the cell wall. Pectin provides __________ to compression.

Answer 36

tensile | resistance

Question 37

what chemicals enable the expansion of the plant cell wall and how do they do this?

Answer 37

expansins interact and loosen the inter molecular forces. polymers slide over each other for the plant to grow

Question 38

describe auxins effect on the cell wall permeability

Answer 38

enzymes controlled by pH, cell wall pH is controlled by proton pumps. proton pump activity is controlled by factors including auxin

Question 39

describe how the cell wall grows in relation to cellulose

Answer 39

cellulose molecules alligned in different ways | - growth occurs perpendicular to the allignment of the microfibirls

Question 40

describe how microfibres are controlled by enzyme complexes

Answer 40

emzyme complexes generating cellulose move along the membrane but cant pass the microtubules - acts like railway tracks by directing their movement

Question 41

``` generalised functions of the following - auxin cytokinin - gibberlelin - abscisic acid - ethylene - brassinosteroids ```

Answer 41

auxin - growth promoter cytokinin - cell division promoter, senescene inhibitor gibberellin - growth promoter, seed germinator abscisic acid - growth inhibitor promote senescence ethylene - inhibit growth promote fruit ripening bassinosteroids - inhibit growth

Question 42

where does gibberelic acid lead to seed growth? how does it do so?

Answer 42

in germination of seeds - indirect outcome of amylase production stimulating starch breakdown to release sugars for growth -

Question 43

plants will move towards _____ and _____ light but away from _____ light

Answer 43

blue and white | red

Question 44

thigmotropism

Answer 44

touch sensitivity in plantz

Question 45

seed germination is promoted by _______ light at ___nm. seed germination is inhibited by _______ light at _____.

Answer 45

red - 670 | far red - 700

Question 46

short day plants have a critical threshold of night length under which they _____

Answer 46

will grow

Question 47

describe phytochrome

Answer 47

consists of two identical proteins joined to form one functional molecule chromophore - absorbs a wavelngth of light light receptor that phosphoryolases a kinase enzyme

Question 48

describe the forms of phytochromes and how you get from one to the other

Answer 48

switches between Pr and Pfr Pr is inactive shine red light and it becomes Pfr and is activated - kinase now active shine far red and becomes inactive Pr form again

Question 49

describe the signals the phytochrome can send

Answer 49

alters the expression of levels of transcription factor FT in leaves - transported to the meristem to alter fate

Question 50

how do plants respond to gravity

Answer 50

statoliths at the root tip mediate gravity response heavy starch granules shift down one side and promote growth

Question 51

describe the plants response to a biotic factor: a catipillar eating its leaf

Answer 51

catippilar nibbles at leaf chemical in the saliva causes signal transduction pathway synthesising volatile attractants. catipillar predators become evolved to follow the volatilies to kill the catapillars

Question 52

describe how agrobacterium can manipulate a plants development

Answer 52

trasnfers its DNA into plant cells form galls - mass of cells

Question 53

_____ attractants cause bacterium to get closer to the plant. the bacteria then release _____ factors which are ________ causing the ______ to close

Answer 53

chemo nod oligosaccharides root hairs

Question 54

what is a signal transduction response

Answer 54

where signals are percieved by a receptor and passed on

Question 55

list the order of plant evolution

Answer 55

``` charophyceans bryophytes pteridophytes gymnosperms angiosperms ```

Question 56

higher plants have a ______ sporophyte and a ______ gametopjyte

Answer 56

dominant | minor

Question 57

lower plants have a ______ sporophyte and a _____ gametophyte

Answer 57

minor | dominant

Question 58

how large is the gametophyte stage in angiosperms

Answer 58

8 cells surroned by sporophyte tissue

Question 59

eggs come from the _________ and sperm from the _______ in ferns

Answer 59

archegonium | antheridium

Question 60

three bits of evolutionariy evidence for conservation of the development of stomata

Answer 60

moss and arabidopsis have the same transcription factors mutation of homologus genes in distinct lines leads to similar phenotypes swapping gene of moss to arabidopsis gives normal phenotype

Question 61

evidence for the root hair being evolutionariliy conserved

Answer 61

RHD like gene from a bryophyte into angiosperm mutant without root hairs restores root hairs

Question 62

use duckweed to describe why asexual reproduction can be advantegous

Answer 62

rapid reproducing - double in less than 30 hours take up all the sun on the pond and outcompete