Untitled Flashcard Set

Base-pair substitution

A mutation where one nucleotide in the DNA sequence is replaced with another.

DNA ligase

An enzyme that connects DNA fragments by forming covalent bonds between the sugar-phosphate backbones.

DNA polymerases

Enzymes responsible for synthesizing new DNA strands by adding nucleotides complementary to the template strand.

Exons

Coding segments of eukaryotic genes that are retained in the mature mRNA after splicing.

Frame shift mutations

Mutations caused by insertions or deletions that shift the reading frame of the genetic code. This occurs when nucleotides are added or removed in numbers not divisible by three, leading to altered protein synthesis.

Helicase

An enzyme that unwinds the DNA double helix during replication.

Introns

Non-coding segments of eukaryotic genes that are removed during mRNA processing.

Mismatch repair

A cellular process that corrects erroneous insertions, deletions, and mis-incorporated bases during DNA replication.

Missense mutations

Mutations that result in the substitution of one amino acid for another in the protein sequence.

Mutagens

Agents that increase the rate of mutations in DNA.

Nonsense mutations

Mutations that create a premature stop codon in the protein coding sequence.

Nucleotide Excision Repair

A DNA repair mechanism that removes damaged nucleotides and replaces them with correct ones.

Point mutations

Gene mutations involving changes to a single nucleotide in the DNA sequence. Either substituted, inserted, or deleted.

RNA Primer

A short segment of RNA synthesized to provide a starting point for DNA polymerases during replication.

Promoter

A specific region of DNA located upstream (5') of a gene that initiates transcription by acting as the binding site for RNA polymerase and associated transcription factors. It acts as a switch to turn genes on or off, determining when and where a gene is expressed within an organism. 

RNA polymerase

An enzyme that synthesizes RNA from a DNA template during transcription.

RNA processing

The modifications a pre-mRNA undergoes before becoming a mature mRNA. It increases transcript diversity, ensures stability, and allows export to the cytoplasm for translation, with errors in this process often leading to genetic diseases. 

RNA splicing

The process of removing introns from pre-mRNA and joining exons together to form mature mRNA.

Spliceosome

A complex of proteins and RNA that removes introns from pre-mRNA.

Telomere

The protective end of a linear chromosome that prevents deterioration or fusion with neighboring chromosomes.

Transcription factors

Proteins that help regulate the transcription of specific genes by binding to nearby DNA. By recruiting or blocking RNA polymerase, they control the rate of transcription, playing critical roles in cell differentiation, development, and response to external signals. Transcription factors are essential for gene expression and regulation, influencing various cellular processes.