february 2019 unit R2101 past paper

Question 1

what is meant by the leaf petiole?

Answer 1

attaches leaf to stem

contains vascular bundles of xylem and phloem

supports leaf in high wind/rain

allows leaf to track sun throughout day for maximum photosynthesis

Question 2

what is meant by the leaf lamina?

Answer 2

leaf blade, or flattened surface of leaf

Question 3

what is meant by the leaf vein?

Answer 3

contains xylem and phloem in leaf vascular bundles

Question 4

what is meant by the leaf midrib?

Answer 4

main central vein of leaf
smaller veins run off it
runs from leaf base to tip

Question 5

where are the epidermis and phloem tissues found in a dicot leaf?

Answer 5

epidermis is: layer beneath the cuticle, it is the outer layer of the leaf

phloem: located in the vascular bundles (in spongy mesophyll)

Question 6

what are two characteristics of the epidermis in a dicot leaf?

Answer 6

guard cells, stomata present, transparent, single layer of cells or hairs

Question 7

what are the functions of some of the characteristics in a dicot leaf?

Answer 7

reduce/control water loss, enable gas exchange, produce a waxy cuticle, protection from pest/disease/damage.

Question 8

describe a tap root

Answer 8

derives from radicle, is primary root

Question 9

describe adventitious roots

Answer 9

roots originate from other plant parts eg; stem or leaves.

can also come from organs eg bulbs/tubers and are usually fibrous

Question 10

what is the purpose of the root cap?

Answer 10

protects the root from damage as it grows through the soil

produces a lubricant to aid this process

Question 11

what is the function of the apical meristem?

Answer 11

it is the site of cell division (meristematic)

longitudinal root growth takes place here

Question 12

what is the function of the cortex in a root tip?

Answer 12

a packing tissue or,

starch storage tissue

Question 13

what is the function of the root hair?

Answer 13

main area for water and mineral uptake-they also increase the surface area for water uptake.

the hairs are small enough to get in between soil particles

Question 14

state in words the basic equation for aerobic respiration

Answer 14

oxygen and sugar ——-> carbon dioxide + water+ energy

Question 15

identify two differences between aerobic and anaerobic respiration

Answer 15

anaerobic respiration takes place without oxygen
“ “ “ “ produces ethanol
“ “ “ “ generates less energy
it takes place in the cytoplasm

Question 16

what is the significance of aerobic respiration in the storage of fruits? (5 marks)

Answer 16

fruit, although detached from plant is still respiring, so the faster the respiration rate, the shorter the storage time

you can increase storage time by refrigeration, dark/dry/cool atmospheres (decrease oxygen amount available) increase carbon dioxide levels in an environmentally controlled store and better packaging.

Question 17

how are stems adapted for natural vegetation?

Answer 17

stolons
runner
rhizome
corm
stem tuber

Question 18

describe a stolon adaption

Answer 18

a horizontal stem close to ground, which roots and produces daughter plants at its tips or nodes
eg: Ranunculus repens

Question 19

describe a runner

Answer 19

a horizontal stem close to the ground
it produces plantlets from nodes along its length
eg: Fragaria x ananassa

Question 20

describe a rhizome

Answer 20

its an underfround/near the surface stem which roots/brances at nodes eg: Iris germanica

Question 21

describe a corm

Answer 21

swollen, compressed stem that produces new corms above the ols one
eg: Crocus thommasinianus

Question 22

describe a stem tuber

Answer 22

underground stem with new shoots and roots arisinf from nodes (eyes)
eg: Solanum tuberosum (potato)

Question 23

how does a plant cell take up nutrients?

Answer 23

achieved by active transport across the cell membrane on protein carriers.
Selective and energy dependent-minerals usually moved against a concentration gradient into the cell

Question 24

two functions of fruits are?

Answer 24

protect seed from damage
aid seed dispersal
aid dormancy
delay germination of seed

provision of nutrients for seed as it develops on the plant

Question 25

three methods by which seeds are dispersed by animals

Answer 25

Animal frugivory-fruit eaten and passed through gut, then excreted elsewhere animal attachment/scattering: fruit attaches to coat and carried off. Brushed off elsewhere and may germinate animal hoarding: squirrels bury underground fruit but forget where it was

Question 26

two plant examples which have fruits dispersed by animals

Answer 26

frugivory: Malus domestica (apple) attachment: Galium aparine (goosegrass aka sticky willy) hoarding: Quercus robur

Question 27

state the meaning of monoecious and give a plant example

Answer 27

plants have separate male and female flowers on the same plant eg Quercus robur (common oak) Zea mays (corn) Betula pendula

Question 28

state the meaning of dioecious and give a named plant example

Answer 28

plants have male and female flowers on separate plants eg: Ilex aquifolium (holly)

Question 29

how do flower parts assist a bee in pollination?

Answer 29

petals: brightly coloured (blue/yellow) which they prefer Landing platform to support weight form a tube to match length of bees tongue Nectar guides on petals to direct bee to nectary at base of petal Nectaries that contain sugary liquid nectar for them to feed on-also draws them further into flower. Stigma-positioned to brush against the bee and are also sticky to attach the pollen stamens/anthers positioned to brush against bee anthers contain sticky pollen

Question 30

name three environmental conditions that increase the rate of water loss from plant leaves

Answer 30

increase in temp high wind speed low humidity high light levels

Question 31

what are three leaf adaptions to limit water loss?

Answer 31

``` leaf hairs sunken stomata needles spines thick, waxy cuticle ```

Question 32

how do leaf hairs limit water loss?

Answer 32

reduce wind speed, trap moisture increase humidity close to leaf surface shade it-reducing light and temp

Question 33

how do sunken stomata limit water loss?

Answer 33

reduce wind speed and increase humidity close to stomata

Question 34

how do needles limit water loss?

Answer 34

reduction in surface area eg: conifer

Question 35

how do spines limit water loss?

Answer 35

they are modified leaves with a reduced area-also shade the leaf reducing light and temp

Question 36

how do rolled leaves limit water loss?

Answer 36

reduce leaf area, | trap humid air within leaf close to stomata

Question 37

how does a thick, waxy cuticle limit water loss?

Answer 37

enhances waterproofing of the leaf so minimises water loss

Question 38

two benefits of senescene plants or plant organs in horticulture are?

Answer 38

seeds are ready to collect for propagation or as a food crop autumn leaf colours are attractive leaf colour changing indicates time to harvest onions/potatoes seed heads provide birds with food/ornamental interest in winter can use the plant material to make compost energy taken back into plant from the leaves is used by bulbs and other organs for growth the following year

Question 39

what are some limitations of senescene plants/organs in horticultural situations?

Answer 39

the leaves/plants may be unsightly in an ornamental boarder so need removing in winter flowering has finishes so loss in quality/value for cut flowers loss of value in fruit crops falling leaves can damage lawns/be slip hazards self-seeding leaves can result in a weed problem in an ornamental boarder scenescene plant material can harbour pests and diseases