Question

Prompt Comparing amino acid sequences in proteins has been used to determine the relatedness of organisms. Below is a graphic that shows the amino acid sequence differences between different organisms for a protein keratin. Changes in amino acid sequences are known to cause changes in structure of proteins. Part A. Consider species A, D, and E. Using the data provided, describe how the structures of their keratin proteins would compare. Part B. Keratin is made up of about 450 amino acids. Determine the similarity in percentages between species A and B, A and C, and B and C. Explain how amino acid sequences can be used in determining how closely related two species are. Part C. Based on this data, predict which two species would be more closely related to one another. Part D. Justify your predictions to part C.

Answer 1

Answer:

A) Species A and E are very closely related more than species A or E are related to species D.

B) Between A and B = 99.1%

Between species A and C =97.5%

Between species B and C = 97.3%

Similarity in amino acids sequence reflects similarity in DNA sequence, therefore they are used to determine how closely species are related.

C) Species A and E are most closely related

D) Since species A and E are most similar in amino acid sequence, it then means that there genetic sequences are most closely related.

Explanation:

A) The amino acid sequences of keratin, in species A and D have a difference of 19 whereas species A and E are different for only one amino acid. Therefore, it means that keratin in species A and D will have significant differences in their structure whereas between species A and E, they would have very similar structures.

Species D and E have a difference of 20 in their amino acids sequences, therefore, the structure of keratin in both species will have significant differences in their structures.

B) Similarity between A and B:

450 - 4 = 446

As a percentage: 446/450 × 100% = 99.1%

Similarity between A and C:

450 - 11 = 439

As a percentage: 439/450 × 100% = 97.5%

Similarity between B and C:

450 -12 = 438

In percentage: 438/450 × 100% = 97.3%

The DNA sequence of species determines their amino acid sequences because information in DNA is transcribed to RNA which are then used to make proteins. Therefore, if a species are very closely related, they are expected to have very similar genetic sequences (or genes) and thus similar proteins too. This similarity in proteins is observed in the similarity between amino acid sequences in their respective proteins.

C). Species A and E are most closely related.

D) Species A and E have only a single difference in their amino acids sequence for Keratin. This is equal to about 99.7% similarity, the highest similarity observed among all the species compared.

Answer 2

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This is the answer to A) Describe how allosteric enzymes are regulated by activator and inhibitor regulatory molecules.

B) Explain how ATP and ADP act as allosteric regulators of enzymes that are responsible for ATP production, and how that is an example of feedback inhibition.

C) What is feedback inhibition? How is the ATP generating pathway discussed in part B an example of feedback inhibition?

Answer:

a} Allosteric regulation is just any form of regulation where the regulatory molecule (an activator or inhibitor) binds to an enzyme someplace other than the active site.The shape of the active site is changed, allowing substrate to bind at a higher affinity.

b) The molecules that bind cellular respiration enzymes act as signals, giving the enzyme information about the cell's energy state. ATP, ADP, and NADH are examples of molecules that regulate cellular respiration enzymes. ATP, for instance, is a "stop" signal: high levels mean that the cell has enough ATP and does not need to make more through cellular respiration.

c) This is a case of feedback inhibition i in which a product feeds back to shut down its pathways.