Answer:
I am pretty sure that the answer is A.
Explanation:
Protein kinases regulate the cell cycle by giving the "go-ahead" or "stop" signal at checkpoints in the cycle. A mutation/disruption in the protein kinases can result in it not doing its job properly. As a result, it can give the 'go-ahead' signal to all cells (mutated or not) to continue through the cell cycle. A distrupted kinase will infleunce the enviornment for a cancer cell as the cancer cell can continue to divide continuously.
I do not think the answer is D because G-couped receptirs are not involed in the regulation of the cell cycle. Additionally, I do not think the answer is C since the production of cAMP (a secondary messgenger amplifies transduction signals; this doesn't have anything to do with cancer?) Finally, between A and B I know that a direct result of cancer is due to a distruption in either protien kinases or growth factors (not in the answer choices). Since one of the factors that leads to cancer is present in answer choice A, I think that is the one. However, this is just my reasoning, I am not 100% sure!
Answer:
No, glycolysis can not be continued without fermentation in the absence of oxygen.
Explanation:
In the absence of oxygen, cells perform fermentation to oxidize NADH into NAD+. NAD+ is required during the conversion of glyceraldehyde 3 phosphate into 1,3 bisphosphoglycerate. Fermentation reduces pyruvate and oxidizes NADH so that the NAD+ supply is continued to ensure continuity of glycolysis.
If fermentation does not occur under anaerobic conditions, cells will accumulate pyruvate and NADH. Glycolysis could not be continued in the absence of NAD+.
Answer:
C
Explanation:
Homologous structures compare the same anatomical features in different species. C is correct because it compares the same trait (wings) in different species (dragonfly vs. bat)
