An action potential involves the transfer SODIUM and POTASSIUM ions across an axon's membrane.
During depolarization, when the ion channels open, they allow the influx of sodium ions into the cell, thus changing the electro-chemical gradient of the cell, in order to counter balance this, potassium ions will be allowed to flow out of the cell.<span />
1. C
2.B
3.C
4. A
5. False
6.True
7.False
8.True
9.True
10. false
Hopefully this help
The answer is A. The insulin, like many hormones binds to cells through receptors found on the cell membrane
Answer:
(1) glycerophospholipids ⟶ (C) lipids with phosphate-containing head groups
(2) cerebrosides ⟶ (D) fatty acid linked through an amide bond to the sphingosine C(2)-amine
(3) gangliosides ⟶ (B) anionic sphingolipids containing one or more sialic acid residues
(4) sphingolipids ⟶ (A) built on sphingosine
Explanation:
1) Choline (Fig. 1) is a glycerophospholipid. It is a glycerol-based lipid with a phosphate-containing head group.
(2) Galactosylceramide (Fig. 2) is a cerebroside. It contains a fatty acid linked through an amide bond to the sphingosine C(2)-amine
(3) Gangliosides are glycosphingolipids that contain sialic acid. GQ1b (Fig. 3) is one of the most abundant gangliosides in the human brain. The carboxyl group of the sialic acid is in the ionic form.
(4) Sphingomyelin (Fig. 4) is a sphingolipid. It is based on sphingosine, with a phosphocholine head and a fatty acid chain.
Answer:
The correct answer is option E. "direct repair using photolyase has removed many of the pyrimidine dimers from the DNA in an error-free manner, so there are fewer lesions for SOS repair to process".
Explanation:
Photolyase is a type of enzyme that catalyses DNA repair from damage caused by exposure to ultraviolet light. Photolyase requires activation by exposure visible light, particularly from the violet end of the visible spectrum. If the Petri plates of the bacteria exposed to UV are located in an incubator that is closely at a large sunny windows, it is very likely that the bacteria is performing direct DNA repair using its photolyase enzymes.