Answer: 1, 2, 4 are accurate.
Explanation:
1. Joe is on a hill (on a trail) above the ocean. The beach and ocean are at similar altitudes. Therefore Joe is at a higher altitude than if he was at the beach.
2. Since Joe is on a hill, he has a higher altitude than at sea level. Air at a higher altitude has lower density because there is less air "ontop" of itself than at lower altitudes. As well, his hill is above the ocean, which means there is a lot of water, making the air more humid than where he is. Humidity also makes air denser.
4.The air pressure will decrease if Joe goes up to higher altitudes because there will be less air on top of itself.
The question is incomplete. The complete question is:
Question: Why do organisms without oxygen need to convert pyruvate to lactate?
A) because pyruvate is toxic to the cells
B) in order to regenerate NAD+
C) in order to use lactate in the citric acid cycle
D) because lactate is needed to produce ATP
Answer:
B) in order to regenerate NAD+
Explanation:
Kreb's cycle and electron transport chain (ETC) are the aerobic stages of cellular respiration. ETC regenerates NAD+ and FAD+ by oxidation of NADH and FADH2 produced during glycolysis and Kreb's cycle. Here, oxygen serves as the terminal electron acceptor.
Glycolytic reactions use NAD+ as an electron acceptor and produce NADH. Therefore, a constant supply of NAD+ is required to sustain glycolysis. In absence of oxygen, ETC cannot occur and organisms convert pyruvate into lactate. Pyruvate is reduced in lactate and NADH serves as the electron donor. Thereby, lactate fermentation regenerates NAD+ to continue the process of glycolysis.
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Eukaryotic transcripts (mRNA) have to undergo capping and splicing before it can be translated.
<h3>RNA processing:</h3>
1. An RNA transcript is first produced in a eukaryotic cell as a pre-mRNA, which needs to be converted into a messenger RNA (mRNA).
2. The RNA transcript is given a 5' cap at the start and a 3' poly-A tail at the end.
3. The process of splicing involves cutting out some RNA transcript segments (introns), then joining the remaining segments (exons) back together.
4. Some genes have the ability to alternate splices, which produces various mature mRNA molecules from the same beginning transcript.
The introns not only do not contain the information necessary to construct a protein, but they also need to be cut off in order for the mRNA to create a protein with the correct sequence. An mRNA with extra "junk" in it will be created if the spliceosome fails to remove an intron, and the translation process will result in the production of the incorrect protein.
Learn more about RNA transcript here:
brainly.com/question/13834206
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