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56 Cards in this Set
- Front
- Back
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arabidopsis thaliana
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mustard weed
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why is mustard weed the best studied model for plant development?
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1) its a simple flowering plant
2) it has a small genome size compared to other plants 3) it is small in size 4) six week generation time |
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How are sperm and egg cells produced in plants?
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from haploid cells (cells with half genes) via mitosis
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What do plant cells develop from?
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pollen grains
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What do pollen grains have on the outside?
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They have protective coat and are carried to flowers by wind, water, or insects or other animals
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describe first step in the process of pollination
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pollen grain interacts with the stigma, which is the top of the carpel
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describe the anatomy of female plant reproductive parts
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the sigma is on top of the carpel, and the ovules are inside the carpel
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second step of pollination
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pollen tube begins to grow and extend down towards the egg cells in the ovules
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what is inside a pollen grain?
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nucleus, cytoplasm, early sperm cell
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what do the nucleus and cytoplasm within the pollen grain do
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manage growth of the pollen tube
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how does the sperm move towards the ovule?
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pollen tube
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how many sperm enter the pollen tube
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two
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double fertilization
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when sperm combines with maternal cell that already contains two haploid nuclei "triploid cell"
then one sperm cells combines with egg cell to make zygote |
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endosperm, how does it form?
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tissue that triploid cell makes when it divides
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What does the endosperm contain?
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nutrients needed for embryonic development, seed germination, and early seedling growth
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what two things does a seed contain?
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embryo and endosperm
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zygote undergoes asymmentric cell division and forms two things
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basal cell and small apical cell
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what does the basal cell do?
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gives rise to the suspensor
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what does the suspensor do?
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anchors the embryo as it develops
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what does the apical cell do?
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give rise to the mature embryo
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what do the asymmetries in the basal and apical cell help do?
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establish the apical-basal axis of the plant
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what axis is established second?
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the radial axis (inside and outside)
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what happens have both axis are formed?
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vegetation organs begin to take shape
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name for initial leaves
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cotyledons
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name for stem-like (stem)
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hypocotyl
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what do the cotyledons and the hypocotyls make up?
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the shoot
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whats the below ground portion?
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root
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two difference in plant/animal growth and development
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in plants it occurs without cell migration
plant embryonic structure take a specific shape because cell divisions occur in precise orientations and resulting cells exhibit differential growth |
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epidermis
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outer protective covering
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where is the ground tissue
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inside the epidermis
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what is ground tissue?
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mass of cells that may later differentiate into specialized cells for photosythesis, food storage, and other functions
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what are the three tissues that arabidopsis form?
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1. epidermis
2. ground tissue 3. vascular tissue |
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what is the function of cells that vascular tissues are in charge of?
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transport water and food between the root and the shoot
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what did scientists do to identify the genes involved in establishing the axes?
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studies arabidopsis mutants with misshapen bodies
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what did scientists specifically focus on in the misshapen plant bodies?
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the apical-basal axis
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what gene is critical in setting up the basal-apical axis?
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MONOPTEROS
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loss of MONOPTEROS causes what?
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lack of hypocotyl and roots
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MONOPTEROS code for...
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MONOPTEROS proteins, a transcription factor
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apical mutant structure
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has hypocotyl and root, missing cotyledon
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central mutant structure
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has cotyledons and root, missing hypocotyl
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basal mutant
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has cotyledon, missing hypocotyl and root
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difference between animal and plant mutants
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the animal has a duplicate structure, the plant has a missing structure
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what do meristems do?
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cause continuous growth and development
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where are the meristems found?
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at the tips of the shoot and the tips of the root (grow in both directions)
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rate and direction of the cell growth are determined by_
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the cell-cell signals produced in response to environmental cues
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germ cells in plants...
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are NOT set aside early in development
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germs cells in plants form
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when shoot meristems convert from vegetative processes to reproductive development
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why do plants have much more genetic diversity than animal cells?
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because mutations occur at every cell cycle and plants have (more rapid? frequent?) cell cycles
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floral meristem
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modified shoot meristem that produces flowers containing the reproductive organs
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four organs of floral meristem:
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1. petal
2. sepals 3. carpel 4. stamen |
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location and function of sepals
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outside of flower, provide protection
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location and function of petals
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inside the sepals, enclose the reproductive organs and are colorful to attract pollinators to them
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location and function of stamens
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inside petals, pollen-producing organs
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location and function of carpels
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middle of flower, contains egg-producing ovules
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ABC model of flowering
3 components: |
1. 3 genes make 2 whorls
2. 4 combos of gene products/signals 3. signals activate different different whorls of diff. meristem tissue |
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MADS box
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DNA-binding domain coded for in floral DNA
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