Differentiate between primary, secondary, tertiary, and quaternary structures of proteins.

Biology

1 answer:

Wittaler [7]3 years ago

4 0

Answer:

Biologists describe the structure of protein at four levels: Primary, secondary, tertiary and quaternary.

Explanation:

1. Primary structure: It is the sequence of amino acids in the polypeptide chain. It only gives us the positional information of amino acids within a protein like which one is first, which one is second and so on. We can see only peptide bonds in primary structure.

Also the first amino acid is known as N-terminal and the last as C-terminal.

2. Secondary structure: The protein thread folds either in the form of helix or beta pleated sheet to form the secondary structure.

In alpha helix, there is hydrogen bonding between every fourth amino acid. Example keratin protein of hair.

In beta pleated sheets, two or more polypeptide strands are held together by intermolecular hydrogen bonding.

3. Tertiary structure: The long polypeptide chain usually folds upon itself like a hollow wollen ball. This is termed as tertiary structure. Involves several linkages like hydrogen bond, hydrophobic bond, ionic bond, covalent bond, van der walls forces. Active sites are formed and protein gains functionality. Example: myoglobin

4. Quaternary structure: Quaternary structure is formed when there are more than one polypeptide chains. For example: hemoglobin has four helical polypeptide chains.

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Populations evolve for many reasons. Suppose there is a small population of birds that have either brown chest feathers or yello

creativ13 [48]

Answer/Explanation:

A. Birds with yellow chest feathers attract more mates and leave more offspring.

Mechanism: The mechanism that is involved in this event is imply that of natural selection. In this event, birds with yellow chest feathers have a greater fitness they attract more mates and leave behind more offspring, as they are selected for by natural selection.

Effect on the gene pool: Since birds of yellow chest feathers have greater fitness, the frequency of yellow feather birds would increase, since more offspring with yellow chest feathers would be produced more than the other bird having the other feather color.

B. A hurricane kills many birds at random.

Mechanism: The mechanism that occurs in this event is simply that of genetic drift. Here, a random change has occurred, which can simply be referred to as the bottle neck effect. Following the disaster, the population size of the bird reduces thereby increasing the chance of allele frequency of the population to change. Genetic drift is occurs more in a small population.

Effect on the gene pool: Allele frequency would change, but not predictably. In other words, since individuals left are chosen by random, and no real idea of which traits would have the highest fitness after the event, we cannot really tell which the pattern of change the allele frequency would take, but we are certain there would be a change in allele frequency.

C. A conservation group releases several new birds to the area, to repopulate the birds. The new birds are predominantly brown feathered.

Mechanism: This event can be described as gene flow, as new members with mostly brown feather are introduced into the population which would eventually bring a change in the gene pool.

Effect on the gene pool: The frequency of brown feather allele will increase. Bearing in mind that the allele frequency of brown feather allele and yellow feather allele is approximately equal, an introduction of new set of birds having mostly brown feathers would definitely bring about a change in the gene pool, leading to more brown feather allele. Hence, frequency of brown feather allele will increase.

8 0

3 years ago

All cells have the same genetic information, but do not express the same genes. How is this possible?

Verizon [17]

I believe the answer is A.

hope this helps! C":

4 0

3 years ago

WHATS THE ANSWER TO 1 AND 2 ASAP PLEASE HELP

elena-14-01-66 [18.8K]

Answer:

D and B