Plant Biology

Question 1

Define “transpiration”

Answer 1

The inevitable consequence of gas exchange in the leaf.

Question 2

Describe structure of xylem

Question 3

Outline gas exchange that occurs through leaf stomata

Question 4

Outline structures and mechanisms involved in the flow of water from roots to leaves

Answer 4

Cohesive properties:
- The cohesive properties of water allows it to move against gravity from root to leaf

Question 5

Outline how xylem is able to maintain rigidity even under low pressure or mechanical disturbance

Question 5

Outline polarity of water molecule

Answer 5

Oxygen atom: negative
Hydrogen atoms: positive

Question 6

Define “cohesion”

Question 7

Explain the decrease in pressure and transpiration-pull that results from evaporation of water from the leaf

Question 8

State the transpiration is a passive processes

Question 9

Explain why roots are hypertonic relative to the soil

Question 10

Outline the role of active transport in maintaining root tonicity

Question 11

Describe how water enters roots from the soil

Question 12

Compare the symplastic and apoplastic pathways of water transport through the root

Answer 12

Symplastic:

Apoplastic:

Question 13

Outline strategies used by xerophytes and halophytes to reduce water loss

Question 13

Define “xerophyte” and “halophytic”

Answer 13

Xerophyte:

Halophytic:

Question 14

Describe simple models of water transport, inclusive of evaporation, adhesion and cohesion

Question 14

Draw a xylem vessel tube, labeling cellulose wall and helical lignin thickening

Question 15

Describe the use of a potometer to measure transpiration rates

Question 15

State a similarity and a difference between transpiration models and transpiration in plant tissues

Question 16

List example source and sink tissues

Answer 16

Source tissues:

Sink tissues:

Question 16

​Define “translocation”, “phloem sap”, “source” and “sink”

Answer 16

Translocation:

Phloem sap:

Source:

Sink:

Question 17

State that phloem transport is bidirectional

Question 18

​Outline why pressure in the phloem increases due to the movement of water into the phloem

Question 19

State that sucrose is the most prevalent solute in phloem sap

Question 20

Outline why sucrose is used for phloem transport, as opposed to glucose

Question 20

Describe the active transport of sucrose into the phloem via a co-transport protein

Question 21

State that the phloem becomes hypertonic to xylem due to the active transport of sucrose into the phloem

Question 21

State that water moves into the phloem by osmosis

Question 22

State that water moves from area of higher pressure to area of lower pressure and that the movement of water also moves the solutes dissolved in it

Question 23

State that the function of phloem includes loading of carbohydrates at a source, transport of carbohydrates through the plant, and unloading of carbohydrates at a sink

Question 24

Outline the structure and function of sieve tube cells, with specific mention of the rigid cell wall and sieve plates

Question 25

Outline the structure and function of companion cells, with specific mention of mitochondria and cell membrane infolding

Question 26

State two ways xylem cells can be identified in cross sections of stem and root

Question 27

Identify xylem given microscope images of stem and root

Question 28

Identify phloem within the vascular bundle of a stem and root

Question 29

State that aphids consume phloem sap as the main component of their diet

Question 30

Outline how aphids have been used to measure the rate of flow and composition of phloem sap

Question 31

Outline how radioactive carbon isotopes are used to study translocation

Question 31

Define "indeterminate growth" and "totipotent"

Question 31

Define "meristem"

Question 32

State that most plants have indeterminate growth and have totipotent cells

Question 33

Compare apical and lateral meristems

Answer 33

Apical meristems: Lateral meristems:

Question 33

Outline role of mitosis in the growth of stem and leaves while maintaining a meristem

Question 34

State the generic function of plant hormones

Answer 34

Control growth in the shot apex

Question 35

Outline how auxin concentrations regulate plant growth in the root and stem

Question 36

Outline the role of auxin in apical dominance

Question 37

State two external factors that control the growth of roots and stems

Question 38

Define "tropism", "phototropism" and "gravitropism"

Answer 38

Tropism: Phototropism: Gravitropism:

Question 38

Outline how PIN-transport proteins can direct direction of auxin flow

Question 38

Explain how auxin concentrations allow for phototropism in the stem

Question 38

Explain how auxin concentrations allow for gravitropism in the root

Question 39

State that auxin influences cell growth rates by changing gene expression

Question 39

Define "micropropagation"

Question 40

Outline how changing auxin and cytokinin ratios can lead to development of roots or shoots from the same explant tissue

Question 41

Outline three roles of micropropagation of plant species

Question 42

Outline role of microarrays in understanding role of plant hormones

Question 42

Compare the vegetative and reproductive phases of the angiospermatophyta life cycle

Question 42

State that flowers are produced from a shoot apical meristem

Question 43

State two abiotic factors that may trigger flowering

Question 44

Compare the timing of flowering in short-day plants and long-day plants

Question 44

Outline the process by which changes in gene expression trigger flowering

Question 45

State the role of the pigment phytochrome

Question 46

Describe the conversions between the two forms of phytochrome

Question 47

​Define "pollination", "fertilization" and "seed dispersal"

Answer 47

Pollination: Fertilization: Seed dispersal:

Question 47

State the changes to the ovule and ovary that result from fertilization

Question 47

Describe role of phytochrome in controlling flowering in long and short day plants

Question 48

List mechanisms of seed dispersal

Question 49

Define "mutualism"

Question 50

Explain an example of mutualism between a flowering plant and its pollinator

Question 51

State how plants can be manipulated to force flowering out of season

Question 52

Draw and label the structure of seeds, including: - Embryo root - Embryo shoot - Cotykedons - Testa - Micropyle - Hilum

Question 53

State the function of the different parts of the seed

Answer 53

Embryo root: Embryo shoot: Cotykedons: Testa: Micropyle: Hilum:

Question 54

Draw and label an animal pollinated flower, including: - Petals - Sepals - Anthers - Filaments - Carpel - Stigma - Style - Ovary - Ovule

Question 55

State the function of the different parts of the animal-pollinated flower

Answer 55

Petals: Sepals: Anthers: Filaments: Carpel: Stigma: Style: Ovary: Ovule:

Question 56

Define "germination"

Question 57

Outline the role of gibberellin during germination

Question 58

Outline why water, oxygen and warmth are required for germination

Question 59

Write five example problem questions for experiments that could test factors affecting germination

Question 60

Contrast traditional conservation efforts with newer strategies of conservation