Term
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Definition
1) Lipid-soluble (small, hydrophobic) signal diffuses across plasma membrane into cell.
2) Signal binds to receptor, inducing conformational change or binding to a carrier.
3) Complex binds to DNA, inducing a change in cell activity.
- No membrane proteins are required! |
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Term
| Intermembrane Signal Receptors |
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Definition
1) Signal (ligand) is received.
2) Signal is transduced.
3) Signal is amplified.
4) Cell responds. |
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Term
| Advantages of Fertilization in the Open Ocean |
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Definition
| Cheap, long distance, synchronizable. |
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Term
| Disadvantages of Fertilization in the Open Ocean |
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Definition
| Low probability of success in massive expanse of water, many predators, confusion between species. |
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Term
| To help the sperm find the egg |
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Definition
| Egg releases a small 10-aa peptide 'resact;' resact diffuse from the egg into nearby water; sperm use this concentration gradient to guide towards egg. |
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Term
| Sperm have two swim motions |
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Definition
| When little or no ligand is binding to receptor, "turn." When more resact receptor is bound to ligand, "straight." |
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Term
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Definition
1) Sperm contacts jelly layer.
2) Acrosomal reaction begins.
3) Digestion of jelly layer.
4) Binding to vitelline envelope.
5) Sperm lyses hole in vitelline envelope. Fusion of acrosomal process membrane and egg membrane.
6) Sperm nucleus and centriole enter egg. Sperm nucleus then fuses with egg nucleus. |
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Term
| ________ is exposed along the acrosomal process. |
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Definition
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Term
| What does Bindin bind to? |
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Definition
| The fertilizin receptor on the egg. |
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Term
| What happens to the sperm if the sperm does not enter the egg? |
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Definition
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Term
| What happens to the egg if the sperm does not enter the egg? |
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Definition
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Term
| What happens to the sperm if 1 sperm enters? |
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Definition
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Term
| What happens to the egg if 1 sperm enters? |
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Definition
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Term
| What happens to the sperm if 2 sperm enter the egg? |
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Definition
| Small, small chance of life. |
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Term
| What happens to the egg if two sperm enter the egg? |
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Definition
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Term
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Definition
1) Egg is covered with sperm. One sperm enters.
2) Fertilization envelope begins to lift and clear away excess sperm.
3) Fertilization envelope expands across egg.
4) Completed fertilization envelope has cleared away all excess sperm. |
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Term
| Blocking polyspermy: Cortical Granules |
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Definition
| Calcium wave causes cortical granules to fuse with egg plasma membrane; carbohydrates are released into the inter-layer space; this thick fluid absorbs water and swells, pushing away the vitelline envelope. |
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Term
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Definition
| Uses the change in membrane potential in the egg to help protect against a second sperm; change in membrane potential rapidly and temporarily distorts fertilizin structure; this inactivates all fertilizin molecules for about six seconds. |
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