flashcards

These flashcards cover major topics in biology, such as translation, mutations, and protein structure. Each card includes a term and its definition to aid in exam preparation.

Ribosome structure

Consists of a large subunit and small subunit made of proteins and RNA, containing tRNA binding sites: A (acceptor), P (peptidyl), and E (exit) sites.

Initiation of translation in eukaryotes

The small ribosomal subunit binds to the 5' cap of mRNA, forming an initiation complex with tRNA before the large subunit joins.

Termination in translation

Involves a release factor protein that recognizes the stop codon and allows for the release of the polypeptide chain.

Polysomes

Structures formed by multiple ribosomes translating the same mRNA simultaneously, speeding up the process of translation.

Post-translational Modifications

The process involving changes to a protein after translation, including proteolysis, glycosylation, and phosphorylation.

Mutations

Changes in DNA that can occur during replication, meiosis, or be induced by environmental factors, potentially altering gene expression and protein function.

Point mutations

Mutations that occur at a single base pair, including substitution, insertion, and deletion.

Silent mutation

A point mutation that does not change the amino acid sequence of the protein due to redundancy in the genetic code.

Missense mutation

A mutation that results in a different amino acid in the protein sequence.

Nonsense mutation

A mutation that creates a premature stop codon, leading to truncated proteins.

Wobble base pairing

A mechanism allowing tRNA anticodons to pair with multiple codons in mRNA due to flexible binding.

Phosphorylation

The addition of phosphate groups to proteins, which can activate or deactivate them by changing their conformation.

Chaperone proteins

Proteins that assist in the proper folding of other proteins during post-translational processing.

Tertiary structure

The three-dimensional structure of a protein formed by interactions between functional groups.

Quaternary structure

The level of protein structure that involves the assembly of multiple polypeptide chains.

Signal sequences

Short sequences of amino acids that guide proteins to their final destination within or outside the cell.

Proteolysis

The process of cleaving polypeptides into smaller units or amino acids.

Glycosylation

The addition of sugar molecules to proteins, affecting their function and stability.

Translocation

A chromosomal rearrangement where a segment of DNA is moved from one location to another.