Plant Biology Flashcards
Transport in the xylem of plants, Transport in the phloem of plants, Growth in plants, Reproduction in plants
Define “transpiration”
The inevitable consequence of gas exchange in the leaf.
Describe structure of xylem
Outline gas exchange that occurs through leaf stomata
Outline structures and mechanisms involved in the flow of water from roots to leaves
Cohesive properties:
- The cohesive properties of water allows it to move against gravity from root to leaf
Outline how xylem is able to maintain rigidity even under low pressure or mechanical disturbance
Outline polarity of water molecule
Oxygen atom: negative
Hydrogen atoms: positive
Define “cohesion”
Explain the decrease in pressure and transpiration-pull that results from evaporation of water from the leaf
State the transpiration is a passive processes
Explain why roots are hypertonic relative to the soil
Outline the role of active transport in maintaining root tonicity
Describe how water enters roots from the soil
Compare the symplastic and apoplastic pathways of water transport through the root
Symplastic:
Apoplastic:
Outline strategies used by xerophytes and halophytes to reduce water loss
Define “xerophyte” and “halophytic”
Xerophyte:
Halophytic:
Describe simple models of water transport, inclusive of evaporation, adhesion and cohesion
Draw a xylem vessel tube, labeling cellulose wall and helical lignin thickening
Describe the use of a potometer to measure transpiration rates
State a similarity and a difference between transpiration models and transpiration in plant tissues
List example source and sink tissues
Source tissues:
Sink tissues:
Define “translocation”, “phloem sap”, “source” and “sink”
Translocation:
Phloem sap:
Source:
Sink:
State that phloem transport is bidirectional
Outline why pressure in the phloem increases due to the movement of water into the phloem
State that sucrose is the most prevalent solute in phloem sap
Outline why sucrose is used for phloem transport, as opposed to glucose
Describe the active transport of sucrose into the phloem via a co-transport protein
State that the phloem becomes hypertonic to xylem due to the active transport of sucrose into the phloem
State that water moves into the phloem by osmosis
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
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
Outline the structure and function of sieve tube cells, with specific mention of the rigid cell wall and sieve plates
Outline the structure and function of companion cells, with specific mention of mitochondria and cell membrane infolding
State two ways xylem cells can be identified in cross sections of stem and root
Identify xylem given microscope images of stem and root
Identify phloem within the vascular bundle of a stem and root
State that aphids consume phloem sap as the main component of their diet
Outline how aphids have been used to measure the rate of flow and composition of phloem sap
Outline how radioactive carbon isotopes are used to study translocation
Define “indeterminate growth” and “totipotent”
Define “meristem”
State that most plants have indeterminate growth and have totipotent cells
Compare apical and lateral meristems
Apical meristems:
Lateral meristems:
Outline role of mitosis in the growth of stem and leaves while maintaining a meristem
State the generic function of plant hormones
Control growth in the shot apex
Outline how auxin concentrations regulate plant growth in the root and stem
Outline the role of auxin in apical dominance
State two external factors that control the growth of roots and stems
Define “tropism”, “phototropism” and “gravitropism”
Tropism:
Phototropism:
Gravitropism:
Outline how PIN-transport proteins can direct direction of auxin flow
Explain how auxin concentrations allow for phototropism in the stem
Explain how auxin concentrations allow for gravitropism in the root
State that auxin influences cell growth rates by changing gene expression
Define “micropropagation”
Outline how changing auxin and cytokinin ratios can lead to development of roots or shoots from the same explant tissue
Outline three roles of micropropagation of plant species
Outline role of microarrays in understanding role of plant hormones
Compare the vegetative and reproductive phases of the angiospermatophyta life cycle
State that flowers are produced from a shoot apical meristem
State two abiotic factors that may trigger flowering
Compare the timing of flowering in short-day plants and long-day plants
Outline the process by which changes in gene expression trigger flowering
State the role of the pigment phytochrome
Describe the conversions between the two forms of phytochrome
Define “pollination”, “fertilization” and “seed dispersal”
Pollination:
Fertilization:
Seed dispersal:
State the changes to the ovule and ovary that result from fertilization
Describe role of phytochrome in controlling flowering in long and short day plants
List mechanisms of seed dispersal
Define “mutualism”
Explain an example of mutualism between a flowering plant and its pollinator
State how plants can be manipulated to force flowering out of season
Draw and label the structure of seeds, including:
- Embryo root
- Embryo shoot
- Cotykedons
- Testa
- Micropyle
- Hilum
State the function of the different parts of the seed
Embryo root:
Embryo shoot:
Cotykedons:
Testa:
Micropyle:
Hilum:
Draw and label an animal pollinated flower, including:
- Petals
- Sepals
- Anthers
- Filaments
- Carpel
- Stigma
- Style
- Ovary
- Ovule
State the function of the different parts of the animal-pollinated flower
Petals:
Sepals:
Anthers:
Filaments:
Carpel:
Stigma:
Style:
Ovary:
Ovule:
Define “germination”
Outline the role of gibberellin during germination
Outline why water, oxygen and warmth are required for germination
Write five example problem questions for experiments that could test factors affecting germination
Contrast traditional conservation efforts with newer strategies of conservation
