Answer:
d
Explanation:
look at it it's all over the place
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.
Answer:
Index fossils
Explanation:
The index fossils are the fossils that come in very handy for the geologists when it comes to identifying or dating rock samples or other fossils. The reason for this is that the index fossils have already been dated. They are fossils that are very commonly found, wide dispersed, are easy to be identified, and are limited to only a certain geological period. These characteristics make them an excellent indicator for the dating of the rock layers in which they are found, or the fossils found in the same layers with them, without conducting further examinations.
Answer:
osmosis is the movement of water molecules from a region of lower concentration to a region of higher concentration through a semi permeable membrane
Explanation:
note: osmosis only occurs in liquids
and a semipermeable is a membrane with very tiny holes that allows solvent molecules to pass through it readily but does not allow solute particles to pass through it
Answer:
2. Circular, looped, folded, single stranded DNA known as the bacterial chromosome
Explanation:
The bacterial chromosome of a prokaryotic cell, does not occur in the typical X chromosome found in eukaryotic cells, but it is a long folded and looped molecule composed of double-stranded supercoiled DNA. In this case, DNA occurs freely and covalently closed in a circular shape in the cytoplasm and it does not bind with proteins.
