Question

1) In humans, bone cells and nerve cells have very different functions and produce different sets of proteins. The reason for the observed differences in the proteins expressed by these different cell types within the same individual is that bone and nerve cells contain different

a) DNA Sequences
b) promoters and operations
c) combinations of regulatory proteins
d) operons

2) Which of the following mechanisms is an example of post-transcriptional gene regulation?
a) binding of a repressor protein to an operon
b) alternative splicing of exons in an RNA transcript
c) acetylation of histones in chromatin
d) methylation of specific regions of DNA

Answer 1

C. combinations of regulatory proteins.

B. alternative splicing of exons in an RNA transcript

Step-by-step explanation:

Just wanted to confirm. The explanation above me is correct.

Answer 2

1) c

2) b

Step-by-step explanation:

1) In the vast majority of the cells in the human body, the DNA sequence is the same. How the cells use the information in the DNA is how cells have their own identity. For example, a bone cell will use the DNA very differently from a nerve cell. The answer cannot be a, b or d, because this would involve changes in the DNA sequence.

Instead the answer is c, because the cells express different genes that lead to the production of different sets of proteins. This then further impacts the regulation of the genes specifying each cell type

2) Post-transcriptional gene regulation refers to processes that modify the expression of a gene after transcription. This is distinct from post-translational modification, which is modifications to a protein after it has been translated (e.g. phosphorylation).

DNA methylation (d) represents a potential mechanism of gene regulation prior to transcription. As does (c), as modifications to histone proteins can affect transcription. The binding of a repressor protein (a) also represents changes to gene transcription.

In contrast, alternative splicing of exons in an RNA transcript is a method of post-transcriptional gene regulation. Alternative splicing is a part of RNA processing, and occurs as part of the processing of a primary RNA transcript into a mature RNA. Alternative splicing can produce markedly different proteins.