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39 Cards in this Set
- Front
- Back
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Of fungi, plants, and animals, which express genes at different times?
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All of them.
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Within an hour after fertilization in mammals, the zygote goes through ________ and forms many _________.
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Cleavage, Blastomeres.
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What are the two poles that exist after this? Is there an overall size increase in the fetus?
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Animal and Vegetal pole. No, the fetus is just a larger number of smaller cells.
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What is the name for the fetus when water is drawn into the mass of cells forming a hollow ball?
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Blastula or Blastocyst.
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What is formed when some cells of the blastula push inward?
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Gastrula
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How do the cells of the blastula move?
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They use lamellipodia.
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What are the three germ layers in the gastrula?
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Ectoderm (outer layer), Mesoderm (middle layer), Endoderm (inner layer)
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What do the three germ layers develop into?
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Ectoderm- skin and nerves, Mesoderm- skeleton, muscles, and blood vessels, Endoderm- stomach, lungs, and most internal organs
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What happens in neurulation?
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A zone of the ectoderm on the dorsal surface thickens, and then rolls to form the neural tube. The neural tube later becomes the brain and spinal chord.
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What does the neural crest form? What do somites form?
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Sense organs. Skeletal muscles.
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How many body types do most insects have? What are they?
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Two. Larvae (gather food) and Adult (can fly and reproduce)
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In insect development, which genes produce mRNA before fertilization? What happens to the mRNA and what does it do?
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The maternal genes. It is moved by nurse cells and it determines the initial course of development.
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What is a syncytial blastoderm?
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The cell with about 6,000 nuclei formed after 12 nuclear divisions without cytokinesis that follow fertilization.
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Describe larvae.
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Larvae are formed and begin to feed. They shed their exoskeletons periodically. The go through 3 phases, or instars, in 4 days. It metamorphs into the adult.
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What are imaginal discs?
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Groups of cells in the larvae that do not function in the larvae but form key parts of the adult's body.
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Describe metamorphosis.
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The larvae develops a hard shell and becomes a pupa. The larvae breaks down to feed the imaginal discs. The pupa breaks open releasing the adult.
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How much do plant cells move?
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Very little. They are pretty much in a fixed position when they are created.
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How do plants grow?
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They build new cells around the old ones with meristems.
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In early plant development, the zygote divides into a ball of cells that later become the shoot and a ________ that later becomes the roots.
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Suspensor
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What are the three plant tissues and their function?
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Epidermal- skin, outermost layer, Ground- bulk of plant, food and water storage, Vascular- food and water transport.
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What are cotyledons?
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Seed leaves that store food.
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What happens right after the plant develops cotyledons?
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Development is paused and a seed is formed.
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What is germination?
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The continuation of plant development from a seed. It occurs in response to an environmental stimulus (water, temp, light...).
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What is meristemic development?
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The stage of development where meristems become active and the body of the plant is formed.
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What is morphogenesis?
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The development of the plant body according to the shape of the cells, largely determined by the amount of water present.
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How many somatic cells form from a single fertilized nematode egg?
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959 (The development of each cell of the nematode has been mapped)
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How do cells move?
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They use adhesion molecules. Some tissues have gaps filled with polysaccharide chains that the adhesion molecules bind to.
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What is induction?
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The switching of a cell from one developmental path to another based on interactions with an adjacent cell.
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In some cases of induction, ________ convey position by secreting diffusable _________.
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Organizers, Morphogens
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What does totipotent mean?
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Potentially capable of expressing all genes.
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What is determination? How is it different from differentiation?
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The commitment of a cell to its specialization. Differentiation is the actual specialization of the cell.
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Is determination reversible?
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Yes, but it is a little tricky.
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What is pattern formation?
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The development of the basic pattern of body compartments according to positional information.
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What is the expression of homeotic genes?
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The determination of the form or organ that the body segments will have. The genes involved usually include homeobox.
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What is homeobox?
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The sequence of nucleotides that code for the homeodomain, which regulates gene expression.
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What is apoptosis?
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The process of a cell shriveling, shrinking, and dying in a preprogrammed timeframe.
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What is necrosis?
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The process of injured cells swelling and bursting, releasing their contents into the extracellular fluid.
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What are the theories of aging?
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Accumulated Mutation, Telomeric Depletion (extra DNA at ends shortens with replications), Wear and Tear (cells become damaged with time), Gene clock (genes regulate aging)
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Who made these flashcards?
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Robert Fromm
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