Few questions:
1. What's the difference between protein-based and peptide-based hormones?
2. What does the "recycling of cell debris" stage of apoptosis comprise of?
3. What is the final stage of apoptosis? Signal for macrophages? Cell fragments into apoptotic bodies?
4. Does light energy excite electrons in the ETC of light dependent stage, or is it only used for photolysis?
5. What are "prominent heelbones" and how do they provide a selection advantage?
6. What's the difference between clonal selection and expansion?
7. For inflammation, doesn't vasodilation DECREASE blood pressure? So why is there an increased blood flow?
Thanks so much!
1. Protein based hormones have longer amino acid chains than peptide-based hormones. You don't need to distinguish between them for VCE though, you just need to know that some hormones are amino-acid based (amine, peptide, protein) and some are steroid based.
2. Not really sure on this. I think it just means that after blebs have been phagocytosed the individual components are reused in the body. Not sure whether they would be broken down into base components or entire organelles reused or what though.
3.
According to VCAA 2016
As a wound heals, cells that are no longer needed for the healing process are removed by apoptosis.
Apoptosis is stimulated by external cell signalling from cells such as cytotoxic T cells (Tc).
Outline the main stages in cell apoptosis once stimulated by the Tc cells.
Possible answers included:
• enzymes; for example, caspases are activated within the cell
• digestion of cell contents
• cell shrinkage
• cell blebbing
• cell breaks up
• cell signals macrophages.
Phagocytosis of cell debris was not accepted.
So I'd take this to mean that VCAA believes 'signal for macrophages' is the last step.
4. Haven't got a clue. Definitely not something you need to know for VCE though.
5. Prominent heelbones refers to your heel sticking out. Like if you point your toes you have a bump where your heel is. The selection advantage is that they make bipedalism more efficient and does a better job of supporting the increased weight associated with bipedalism & evolution.
6. Clonal selection is when a B or T cell is activated. Clonal expansion is when it multiplies producing lots and lots of identical daughter cells.
7. Vasodilation does decrease blood pressure but there'll be more blood in the area at any one time because the capillaries are bigger (also it makes it more permeable, which allows white blood cells to cross the membrane as peter.g15 said)
Is enzyme optimal temperature an example of natural selection?
- so only organisms with correct enzyme optimal temperature survived, reproduced, passed on favourable alleles to offspring
Am I overthinking this or would this be correct?
Purely speculation, but given the importance of enzymes I'd imagine that a mutation that resulted in an enzyme functioning less efficiently would probably result in the death of that individual. So in a way yes it would be natural selection. Probably not something you'll ever have to talk about for VCE though haha