Term
| In the biological sense, what is development? |
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Definition
| a single cell that became trillions of cells that composes hundreds of tissue types |
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Term
Why would an organism want to purposely kill off some of its cells? What is it called when this happens in an animal?
In a plant? Give examples in both animals and plants. |
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Definition
cells no longer have a function
in animals its called apoptosis
ex. fingers are webbed until the cells die creating individual fingers like we have now.
plants= programmed cell death
ex. the cells on a leaf scar are programmed to die, to make leaves fall off of the branch. |
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Term
| What does the cell cycle and cell cycle regulation have to do with development? |
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Definition
| the cell cycle goes through three rigorous checkpoints that check that the cell is functioning correctly. the check points are regulated by regulatory genes. and by communication from nearby cells. |
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Term
| When and where does development take place in a plant? In an animal? |
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Definition
P= meristems (shoots and roots) during their entire life.
A= stem cells and other developing cells all over the place finishes when we are adults |
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Term
Distinguish between totipotency and pluripotency. Which would you want if you were cloning a new organism?
Cloning an organ such as a heart or lung? |
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Definition
totipotent= cells that can become any other kind of cell
pluripotent= cells that can become lots of things, but not anything.
I would want totipotent cells if I was cloning something a new organism
If i was making a heart or lung I could use either type of cell but pleuripotent would be better. |
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Term
What does it mean that a cell is terminally differentiated? Are most plant cells terminally differentiated? Most animal
cells? |
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Definition
this means that the cells are at their most specific type, and that they can't change backward in the developmental cycle.
plants are not terminally differentiated because most of them can de-differentiate.
most animal cells are terminally differentiated. |
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Term
| What is a stem cell? Are there different kinds of stem cells? If so, what might they be? |
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Definition
stem cells are undifferentiated cells in animals
yes totipotent and pluripotent. epidermal cells intestinal cells eys blood
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Term
| At what level of expression is development regulated? Why does this make sense? |
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Definition
| variation is always controlled at the transcriptional level. this makes sense because it is the fundamental level of control and it is controlled by the presence of regulatory transcription factors. controls what genes are expressed and therefore the function of each gene. the cell doesn't waste energy making something that it doesn't need. it also prevents accidents. |
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Term
| Since all cells in an organism have the same genes, why do different cells become different things? |
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Definition
| transcriptional gene regulation which controls which genes are then expressed. |
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Term
| Explain what is meant by a developmental cascade, in the sense of gene regulation and development. |
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Definition
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Term
| Explain the conceptual difference between segmentation and segmental identity genes. |
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Definition
segmentation genes= how the body segments are organized where it is
segmental identity genes= they are controlled by homoetoic genes which turn on in linear order during development. they tell segment what they are. what it is |
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Term
| What genes are the major determinants of segmental identity? Why are they called that? |
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Definition
| the Hox genes. this is an abbreviation for the homoeotic complex. (Homeo box) |
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Term
Homeo boxes are conserved across essentially all animals, in both gene order and usually gene function. What does this
tell you about the homeo box genes? |
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Definition
| they are really important in development |
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