BIOL 120- Chapter 8 (part 4)- Molecular Biology

What is the relationship between a gene's coding sequence and the mRNA sequence?

The coding sequence of a gene corresponds to the mRNA sequence that contains the codons necessary for protein synthesis.

What is the coding strand of DNA?

The coding strand, also known as the sense strand, is the strand of DNA that has the same sequence as the mRNA and runs in the 5' to 3' direction.

What is the template strand of DNA?

The template strand, or antisense strand, is the DNA strand that mRNA is built from and runs in the 3' to 5' direction.

What is a gene mutation?

A gene mutation is a permanent alteration of the nucleotide sequence of an organism's genome.

What is a base substitution mutation?

A base substitution mutation is a type of point mutation where one nucleotide and its complementary pair are replaced with another pair of nucleotides.

What is a missense mutation?

A missense mutation is a type of point mutation where a single nucleotide change results in a codon that codes for a different amino acid.

What is a silent mutation?

A silent mutation is a change in a DNA codon that does not result in a change in the amino acid specified by the gene.

What is a nonsense mutation?

A nonsense mutation is a mutation that changes a sense codon into a chain-terminating codon.

What is a frameshift mutation?

A frameshift mutation is caused by insertions or deletions of nucleotides in a DNA sequence that is not divisible by three, altering the entire downstream sequence.

What is translation in the context of genetics?

Translation is the process of converting information provided by mRNA into a specific sequence of amino acids in a polypeptide chain.

Where does transcription occur in prokaryotes and eukaryotes?

In prokaryotes, transcription and translation occur in the cytoplasm; in eukaryotes, transcription occurs in the nucleus and translation occurs in the cytoplasm.

What are the building blocks of proteins?

The building blocks of proteins are amino acids, of which there are 20 different types.

What is the role of tRNA in protein synthesis?

tRNA carries amino acids to the ribosome and has an anticodon that base-pairs with the codon on the mRNA.

What is aminoacylation?

Aminoacylation is the process of adding an amino acid to tRNA, which is catalyzed by aminoacyl-tRNA synthetase and requires ATP.

What are the components of a ribosome?

A ribosome is a ribonucleoprotein complex made up of rRNA and proteins, consisting of a large and a small subunit.

What are the three binding sites of a ribosome?

The three binding sites are the A site (Aminoacyl-tRNA binding site), P site (Peptidyl-tRNA binding site), and E site (Exit site).

What initiates the process of translation?

Translation is initiated when the initiator Met-tRNA binds to the small ribosomal subunit at the start codon (AUG).

What happens during the elongation phase of translation?

During elongation, charged tRNAs enter the A site, and the ribosome synthesizes a polypeptide by moving along the mRNA in the 5' to 3' direction.

What signals the termination of translation?

Translation terminates when a stop codon (UAA, UAG, UGA) enters the A site, causing a release factor to bind and disassemble the ribosomal complex.