DNA and RNA Structure, Function, and Processes

These flashcards cover key vocabulary terms related to DNA and RNA structure, function, and processes, as discussed in the lecture.

Nucleotide

The basic building block of DNA and RNA, consisting of a phosphate group, a sugar, and a nitrogenous base.

Complementary base pairing

The pairing of nitrogenous bases in DNA; adenine pairs with thymine (A/T) and cytosine pairs with guanine (C/G).

Hydrogen bonds in DNA

C/G pairs have 3 hydrogen bonds, while A/T pairs have 2 hydrogen bonds.

Double helix

Structure of DNA composed of two strands twisted around each other, with a sugar-phosphate backbone on the outside and bases on the inside.

Major groove

The larger of the two grooves that form helical structure in DNA where proteins can bind.

Minor groove

The smaller of the two grooves that form in the helical structure of DNA.

Nucleosome

A structural unit of chromatin, consisting of a segment of DNA wound around a core of histone proteins.

Chromatin

The complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells.

Chromosome

A thread-like structure of nucleic acids and protein that carries genetic information.

Gene

A functional organizational unit of information in DNA, often encoding for proteins.

Semiconservative replication

Mechanism of DNA replication where each new DNA molecule consists of one old and one new strand.

Replication fork

The area where the DNA is being unwound and replicated during DNA replication.

DNA polymerase

An enzyme that synthesizes new DNA strands in the 5’ to 3’ direction.

Okazaki fragments

Short sequences of DNA synthesized on the lagging strand during DNA replication.

Telomerase

An enzyme that adds repetitive nucleotide sequences to the ends of eukaryotic chromosomes.

Telomere

The repetitive sequences found at the end of eukaryotic chromosomes that protect them from deterioration.

DNA damage

Injuries to the DNA caused by factors like hydrolysis, UV radiation, and chemicals that can lead to mutations.

Base mismatch repair

A mechanism to fix incorrectly paired nucleotides in DNA.

Nonhomologous end-joining

A repair pathway that joins broken DNA ends without having a homologous template.

Homologous recombination

A type of genetic recombination in which exchange of genetic material occurs between homologous DNA molecules.

Central dogma

The flow of genetic information from DNA to RNA to proteins.

Amplification in gene expression

The increase in the number of copies of a specific gene product, can occur at transcription or translation stages.

RNA vs. DNA

RNA is typically single-stranded and has uracil instead of thymine, while DNA is double-stranded and contains thymine.

Messenger RNA (mRNA)

The RNA that carries genetic information from DNA to the ribosome for protein synthesis.

Translation

The process by which ribosomes synthesize proteins using the genetic information carried by mRNA.

Codon

A sequence of three nucleotides in mRNA that corresponds to a specific amino acid.

Transfer RNA (tRNA)

An adapter molecule that brings the appropriate amino acids to the ribosome during protein synthesis.

Eukaryotic RNA polymerase

An enzyme responsible for synthesizing RNA from a DNA template in eukaryotic cells.

Capping and Poly-A tail

Modifications added to eukaryotic mRNAs that enhance stability and facilitate transport.

Alternative splicing

A process by which different combinations of exons are joined to produce multiple mRNA transcripts from a single gene.

Regulatory DNA sequences

DNA sequences that bind transcriptional regulators to control gene expression.

Transcriptional repressors

Proteins that inhibit gene expression by blocking transcription.

Transcriptional activators

Proteins that enhance gene expression by promoting transcription.

Extracellular signals

External cues that can influence the activity of transcriptional regulators.