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Luba_88 [7]
3 years ago
13

Some Calvin Cycle enzymes contain disulfide bonds that must be reduced through a mechanism involving thioredoxin in order for th

e enzyme to be active in sunlight. What is the name of the key regulatory protein that inactivates these same Calvin Cycle enzymes by oxidation when the sun goes down? Choose the ONE best answer.
Thioredoxin requires sunlight for proper folding into its functional three dimensional structure, so in the absence of light, it is unfolded and cannot reduce these enzymes.
The protein is called ferredoxin-thioredoxin reductase.
There is no regulatory protein that oxidizes these Calvin cycle enzymes; oxidation is spontaneous Sunlight is a reducing energy and moonlight is an oxidizing energy, so when the moon comes out at night, the Calvin Cycle enzymes are oxidized spontaneously.
None of these answers are correct
Thioredoxin has multiple light-sensing properties and when the sun goes down it turns into a strong oxidant.
Biology
1 answer:
Ann [662]3 years ago
8 0

Answer:

There is no regulatory protein that oxidizes these Calvin cycle enzymes; oxidation is spontaneous.

Explanation:

Four enzymes of the Calvin cycle are regulated by sunlight. These enzymes are namely Ribulose 5-phosphate kinase, fructose 1,6-bisphosphatase, sedoheptulose 1,7-bisphosphatase, and glyceraldehyde 3-phosphate dehydrogenase.

The inactive form of these enzymes has disulfide bonds between two Cys residues. In the presence of sunlight, the reduced thioredoxin that obtains electrons from PS-I via ferredoxin reduces the disulfide bonds between the Cys residues of these enzymes.

The reduction of the bonds brings about the confirmation changes to make the enzyme active.

At nightfall, these bonds are spontaneously re-oxidized and there is no reduced thioredoxin available to reduce them again. The spontaneous oxidation of the disulfide bonds of these enzymes at nightfall makes them inactive again.

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Complementary DNA? please help​
topjm [15]

Answer: From top to bottom- T, C, G, A, T, A, T

Explanation:

These are the nitrogenous bases that make up a part of nucleotides in DNA.

There are 4 bases in DNA:

- Adenine

- Guanine

- Thymine

- Cytosine

The bases pair together from A to T and G to C, the way I remember is just reading it as AT GC and it works for me, but you make want to make an acronym if it helps you remember better.

As a result, all you have to do is type in the corresponding base to form the correct base pairs.

3 0
2 years ago
Distinguish between major classes of biomolecules, proteins, lipids, carbohydrates, nucleic acids?
olasank [31]

Answer:

Proteins (polymers of amino acids)

Carbohydrates (polymers of sugars)

Lipids (polymers of lipid monomers)

Nucleic acids (DNA and RNA; polymers of nucleotides)

Explanation:

Proteins:

Chemical formula is CHON

−NH2 + −COOH +R group

Monomer is Amino acids.

Examples are enzymes, and some hormones.

Uses are Storage; Signals; Structural; Contractile; Defensive; Enzyme; Transport; Receptors.

Lipids:

Chemical formula is C:H:O

Greater than 2:1 H:O (carboxyl group)

Monomer is fatty acid and glycerol.

Examples are butter, oil, cholesterol, beeswax.

Functions are energy storage; Protection; Chemical messengers; Repel water.

Carbohydrates:

Chemical formula is C:H:O

1:2:1

Monomer is monosaccharides.

Examples are Glucose, Fructose, Starch, Glycogen, Cellulose.

Uses are energy storage; structure.

Nucleic Acids:

Chemical formula is CHONP

(pentose, nitrogenous base, phosphate ).

Monomer is nucleotides.

Examples are DNA, RNA.

Uses are Genetic information

5 0
3 years ago
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Why the walls of the ventricles are much thicker than the walls of the atria.
Mkey [24]

Answer:

The ventricles of the heart have thicker muscular walls than the atria. This is because blood is pumped out of the heart at greater pressure from these chambers compared to the atria.

Explanation:

hope this helps

8 0
2 years ago
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KATRIN_1 [288]

Answer: The receptor site is the location that a drug binds to, altering the function of a biomolecule.

Explanation:

The drug receptors site, are the sites where the sites where the drug molecules bind.  Basically, a low number of receptors exists and the extent to which the molecules occupy their sites differ with the concentration of drug.  The receptor site changes the conformation and function of the binding molecule of the drug.

5 0
3 years ago
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