Gene Expression

The flow of genetic information from DNA to protein in eukaryotic cells is called the central dogma of Biology.

Explain the role of each of the following in protein synthesis in eukaryotic cells:

RNA polymerase

Codons

Ribosomes

tRNA

Amino Acids

Answer explanation

Your explanation should have been something similar to the response below:

The process of protein synthesis requires the nucleic acids DNA and RNA. The process begins with Transcription in the nucleus. Transcription is the process of converting DNA into mRNA. mRNA is created with the help of an enzyme called RNA polymerase that brings over RNA nucleotides to create the mRNA strand. Once the mature mRNA strand is complete it exits the nucleus through nuclear pores and heads to the ribosomes. The ribosome is the site of Translation. Translation involves reading the mRNA strand in sequences of 3 nucleotides called codons. The codons pair with anticodons on tRNA. The tRNA molecule brings over the associated amino acid molecule. The amino acids are then joined together to create a polypeptide (protein)

What is the difference between replication, transcription, and translation?

Answer explanation

Replication is when DNA uncoils and each strand is used to make a new and complementary strand. Replication must happen before cell division can occur.

Transcription and Translation are the two steps that create Proteins.

Transcription is the process that turns a strand of DNA into mRNA and is the first step of protein synthesis.

Translation is the second step and it occurs in the ribosome. The codons on mRNA are paired up with the anticodons on tRNA. tRNA carries the amino acids that will b bonded together by peptide bonds to form a polypeptide (also known as a protein).

Which of the following describes a prokaryotic cell

• A cell with no nucleus and no membrane-bound organelles

• A cell with a nucleus and membrane-bound organelles.

Which of the following describes a eukaryotic cell?

• A cell with no nucleus and no membrane-bound organelles

• A cell with a nucleus and membrane-bound organelles

Which of the following accurately explains the difference between a missense and nonsense mutation?

• A missense mutation is caused by either a deletion or an addition of a base. The nonsense mutation turns an amino acid into a STOP codon

• The missense mutations creates a frameshift. The nonsense mutation is caused by a substitution of one base and turns the base into a different amino acid.

• Both are types of substitution mutations. A missense mutation changes one amino acid into another one. But a nonsense mutation turns it into a STOP codon.

Answer explanation

View the image to see the dffference between the types of mutations

If Transcription occurs in the nucleus of a prokaryotic cell... then where does it happen in a prokaryotic cell?

• Cytoplasm

• Ribosomes

• It does not occur

Which mutation can cause more drastic changes within the protein

• Substitution - silent

• Substitution - missense

• Frameshift mutation

What is the concept that explains why some genes in different cells are switched on and off. This ability of genes to be turned on and off helps cells to have different functions and shapes even though they all have the same DNA

• Epigenetics (epi=above)

• Subgenetics

• Ribozymes

• Central Dogma

What is the difference between a chromosomal mutation and a point mutation? Which one has greater (worse) effects?

Answer explanation

Chromosome mutations are worse because they impact many genes. Point mutations are less severe because they only impact one gene.