Module 7- Transcription and Translation

Explain the main differences between DNA, RNA, and proteins.

DNA is a stable, double-helixed molecule that stores genetic information. Also made of sugar

RNA is a single-stranded molecule that acts as a messenger, carrying instructions from DNA to build proteins. RNA is also made of sugar

Proteins are the functional product, performing most of the work in cells, based on the instructions copied from DNA into RNA. 

Identify the locations of DNA and the various RNAs in the cell.

DNA is located in the nucleus and mitochondria, while RNA is found in both the nucleus and the cytoplasm. 

Explain the relationship between DNA, a gene, nucleotides, amino acids, and proteins. 

The sequence of these nucleotides dictates the order of amino acids in a protein and the specific sequence of amino acids determine the protein’s structure and function. 

What does this part of the gene do? (Promoter)

This gene is the location where RNA Polymerase attaches to the DNA (so it can perform transcription).

What does this part of the gene do? (Exons)

once introns are removed, exons are spliced together to form the mature messenger RNA (mRNA), which is then translated into protein.

What does this part of the gene do? (Introns)

regions of unwound DNA where new strands are synthesized, serving as the fundamental structure for DNA replication to occur

What does this part of the gene do? (Enhancers)

work with the promoter to increase the rate of transcription, essentially “boasting” the expression of the gene.

What does this part of the gene do? (Silencers)

Prevent or inhibit transcription from occurring effectively, “turning off” the gene.

What does this part of the gene do? (stop codon)

signals the end of the protein-coding region during translation, telling the ribosomes to stop building the protein.

Describe how the process of transcription works.

copying a segment of DNA into a messenger RNA (mRNA) molecule, which involves three main stages: initiation, elongation, and termination.

Describe the structures that are added to and removed from an mRNA transcript before it leaves the nucleus. 

a 5’ cap is added to the beginning, and a 3’ poly A tail is added to the end for transcription and export, while introns are removed and exons are spliced together to create a mature, translatable mRNA.

Explain what alternative splicing is and why it is important for cells. 

It dramatically increases proteomic diversity, allowing a single gene to generate a greater variety of proteins than would be possible otherwise. 

Identify the organelles that perform the process of translation

The ribosome

Describe how the process of translation works.

The messenger RNA (mRNA) is decoded to create a specific sequence of amino acids, which forms a protein.

What is a codon?

a sequence of three consecutive nucleotides in DNA or mRNA that specifies a particular amino acid or a start/stop signal during protein synthesis. 

Explain what differential gene expression is and why it is used in cells. 

It is the process where different genes are turned “on” or “off” in various cells, even though they all have the same genome. Why it’s used is to specialize and diversify them, allowing for the creation of different cell types with unique functions from a single genome. 

Describe the role of transcription factors in differential gene expression. 

regulate gene expression by binding to a specific DNA sequence to either activate or repress the transcription of genes. 

Explain what occurs in a point mutation and a frameshift mutation. 

A point mutation is a change in a single DNA nucleotide, like a substitution, that may or may not alter the resulting protein. A frameshift mutation is caused by an insertion or deletion of nucleotides not in multiple of three, which shifts the entire reading frame for the codons and almost always results in a nonfunctional protein.

How does Silent Mutations affect translation?

result in the same amino acid being coded for, usually due to the redundancy of the genetic code, so the protein is unchanged. 

How do Missense mutations affect translation?

change one amino acid for another, which can alter protein function depending on the new amino acid’s properties and location.

How do Nonsense Mutations affect translation?

create a premature stop codon, leading to a shortened, non-functional protein. 

Identify the major sources of mutations in a cell.

spontaneous errors during DNA replication and mutagens.

Describe how a cell responds to mutations.

by first attempting to repair the damage through systems like mismatch repair.

What is the first amino acid that is added to every amino acid chain?

Met (methionine)

True or False?

 

Cells try to repair their DNA if they detect a mutation.

True

What is present in the pre-mRNA molecule that is generated through the process of transcription?

Both exons and introns

What kind(s) of molecules are made with deoxyribose sugars?

Only DNA

Use the Genetic Code Table above to determine the amino acid sequence made by this mRNA molecule: This question is very simple your literally using a cheat sheet to decode a strand of DNA promise me you’ll pass this question on the exam.

Aight nigga