Answer:
The voltage-gated potassium channels associated with an action potential provide an example of what type of membrane transport?
A. Simple diffusion.
B.<u> Facilitated diffusion.
</u>
C. Coupled transport.
D. Active transport.
You are studying the entry of a small molecule into red blood cells. You determine the rate of movement across the membrane under a variety of conditions and make the following observations:
i. The molecules can move across the membrane in either direction.
ii. The molecules always move down their concentration gradient.
iii. No energy source is required for the molecules to move across the membrane.
iv. As the difference in concentration across the membrane increases, the rate of transport reaches a maximum.
The mechanism used to get this molecule across the membrane is most likely:
A. simple diffusion.
<u>B. facilitated diffusion.
</u>
C. active transport.
D. There is not enough information to determine a mechanism.
Carrier proteins - exist in two conformations, altered by high affinity binding of the transported molecule. Moves material in either direction, down concentration gradient (facilitated diffusion). EXAMPLE: GluT1 erythrocyte glucose transporter.
Channel proteins - primarily for ion transport. Form an aqueous pore through the lipid bilayer. May be gated. Moves material in either direction, down concentration gradient (facilitated diffusion). EXAMPLES: Voltage-gated sodium channel, erytrhocyte bicarbonate exchange protein.
This might be helpful... because I don't know anything about facilitated diffusion.
Answer:
DNA ligase
Explanation:
DNA replication is an enzyme mediated, 3-step process during which the DNA molecule produces a copy of itself. The 3 steps involved are as follows;
- initiation
- elongation
- termination
<em>Initiation </em>involves the unwinding of the double helix structure of the DNA using DNA helicase enzyme
<em>Elongation</em> involves binding of RNA primer to the DNA strands and addition of bases to the primer<em> </em>to elongate the new chains. Bases are added to the leading strand continuously while the lagging strand is replicated in short segments (okazaki segments).
<em>Termination</em> involves the unbinding of RNA primer and substitution of its bases by DNA bases. The Okazaki fragments are then joined together using the DNA ligase enzyme.
<em>The short, numerous segments of DNA observed in the mixture is the Okazaki fragments of the lagging strand. This is due to the absence of the enzyme involved in the joining of these fragments.</em>
Hence, the answer is DNA ligase.
It would likely be cold...
Maybe 40 or 30 degrees?
Answer:
d. platelets
Explanation:
Platelets often referred to as thrombocytes, are membrane-bounded cell fragments that are obtained from the dissociation of bigger precursor cells referred to as megakaryocytes, that are produced from stem cells in the bone marrow.
Platelets are necessary for the blood clotting activities, making it very important for wound healing.
Answer:
D. Enzymes only break down large molecules.
Explanation:
Enzymes are the substances which helps in the broken down of large food molecules into small molecules. It is because our body is not able to absorb large food molecules, these large molecules are broken down into small molecules with the help of enzymes. Carbohydrate is broken down into glucose by amylase and protein is broken down into amino acids by protease. Enzyme is non-living in nature and used as a catalyst in order to speed up the chemical reaction.
