february 2019 unit R2101 past paper Flashcards
what is meant by the leaf petiole?
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
what is meant by the leaf lamina?
leaf blade, or flattened surface of leaf
what is meant by the leaf vein?
contains xylem and phloem in leaf vascular bundles
what is meant by the leaf midrib?
main central vein of leaf
smaller veins run off it
runs from leaf base to tip
where are the epidermis and phloem tissues found in a dicot leaf?
epidermis is: layer beneath the cuticle, it is the outer layer of the leaf
phloem: located in the vascular bundles (in spongy mesophyll)
what are two characteristics of the epidermis in a dicot leaf?
guard cells, stomata present, transparent, single layer of cells or hairs
what are the functions of some of the characteristics in a dicot leaf?
reduce/control water loss, enable gas exchange, produce a waxy cuticle, protection from pest/disease/damage.
describe a tap root
derives from radicle, is primary root
describe adventitious roots
roots originate from other plant parts eg; stem or leaves.
can also come from organs eg bulbs/tubers and are usually fibrous
what is the purpose of the root cap?
protects the root from damage as it grows through the soil
produces a lubricant to aid this process
what is the function of the apical meristem?
it is the site of cell division (meristematic)
longitudinal root growth takes place here
what is the function of the cortex in a root tip?
a packing tissue or,
starch storage tissue
what is the function of the root hair?
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
state in words the basic equation for aerobic respiration
oxygen and sugar ——-> carbon dioxide + water+ energy
identify two differences between aerobic and anaerobic respiration
anaerobic respiration takes place without oxygen
“ “ “ “ produces ethanol
“ “ “ “ generates less energy
it takes place in the cytoplasm
what is the significance of aerobic respiration in the storage of fruits? (5 marks)
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.
how are stems adapted for natural vegetation?
stolons runner rhizome corm stem tuber
describe a stolon adaption
a horizontal stem close to ground, which roots and produces daughter plants at its tips or nodes
eg: Ranunculus repens
describe a runner
a horizontal stem close to the ground
it produces plantlets from nodes along its length
eg: Fragaria x ananassa
describe a rhizome
its an underfround/near the surface stem which roots/brances at nodes eg: Iris germanica
describe a corm
swollen, compressed stem that produces new corms above the ols one
eg: Crocus thommasinianus
describe a stem tuber
underground stem with new shoots and roots arisinf from nodes (eyes)
eg: Solanum tuberosum (potato)
how does a plant cell take up nutrients?
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
two functions of fruits are?
protect seed from damage
aid seed dispersal
aid dormancy
delay germination of seed
provision of nutrients for seed as it develops on the plant
three methods by which seeds are dispersed by animals
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
two plant examples which have fruits dispersed by animals
frugivory: Malus domestica (apple)
attachment: Galium aparine (goosegrass aka sticky willy)
hoarding: Quercus robur
state the meaning of monoecious and give a plant example
plants have separate male and female flowers on the same plant
eg Quercus robur (common oak)
Zea mays (corn)
Betula pendula
state the meaning of dioecious and give a named plant example
plants have male and female flowers on separate plants
eg: Ilex aquifolium (holly)
how do flower parts assist a bee in pollination?
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
name three environmental conditions that increase the rate of water loss from plant leaves
increase in temp
high wind speed
low humidity
high light levels
what are three leaf adaptions to limit water loss?
leaf hairs sunken stomata needles spines thick, waxy cuticle
how do leaf hairs limit water loss?
reduce wind speed,
trap moisture
increase humidity close to leaf surface
shade it-reducing light and temp
how do sunken stomata limit water loss?
reduce wind speed and increase humidity close to stomata
how do needles limit water loss?
reduction in surface area eg: conifer
how do spines limit water loss?
they are modified leaves with a reduced area-also shade the leaf reducing light and temp
how do rolled leaves limit water loss?
reduce leaf area,
trap humid air within leaf close to stomata
how does a thick, waxy cuticle limit water loss?
enhances waterproofing of the leaf so minimises water loss
two benefits of senescene plants or plant organs in horticulture are?
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
what are some limitations of senescene plants/organs in horticultural situations?
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
