Genetics and Viruses Lecture Notes

This set of flashcards covers key vocabulary and concepts related to genetics, nucleotides, and viral replication as discussed in the lecture.

Nucleotide

The building block of nucleic acids, consisting of a phosphate group, a five-carbon sugar, and a nitrogenous base.

Monomer

The smallest subunit that can combine to form larger molecules, such as nucleotides forming nucleic acids.

Covalent Bonding

A type of chemical bond where atoms share electrons.

Nitrogenous Base

A component of nucleotides that provides identity to the nucleotide; includes adenine (A), thymine (T), cytosine (C), guanine (G), and uracil (U).

Purines

A class of nitrogenous bases with a two-ring structure; includes adenine (A) and guanine (G).

Pyrimidines

A class of nitrogenous bases with a single-ring structure; includes cytosine (C), thymine (T), and uracil (U).

Double Helix

The structure formed by two strands of DNA wound around each other, held together by hydrogen bonds between the nitrogenous bases.

Chargaff's Rule

A fundamental rule stating that the amount of adenine (A) equals thymine (T), and the amount of guanine (G) equals cytosine (C) in a DNA molecule.

Leading Strand

The strand of DNA that is replicated continuously in the direction of the replication fork during DNA replication.

Lagging Strand

The strand of DNA that is replicated discontinuously in small fragments away from the replication fork, resulting in Okazaki fragments.

Transcription

The process of synthesizing RNA from a DNA template.

Translation

The process of synthesizing a polypeptide chain (protein) from an mRNA template.

Viruses

A type of pathogen that requires a host cell to replicate; characterized as obligate intracellular parasites.

Lytic Cycle

The viral replication cycle in which the virus infects, reproduces, and ultimately lyses (destroys) the host cell.

Lysogenic Cycle

The process by which a virus integrates its DNA into the host cell's genome, becoming dormant until activated to enter the lytic cycle.

Antiparallel Strands

The orientation of DNA strands, where one strand runs 5' to 3' and the other runs 3' to 5'.

Base Pairing

The specific pairing of nitrogenous bases in DNA; adenine pairs with thymine, and guanine pairs with cytosine.

RNA Polymerase

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

Reverse Transcriptase

An enzyme that synthesizes DNA from an RNA template, characteristic of retroviruses like HIV.

RNA Splicing

The process in eukaryotic cells where introns are removed and exons are joined together to form a mature mRNA molecule.

DNA Polymerase

An enzyme that synthesizes new DNA strands by adding nucleotides complementary to the template strand during DNA replication.

Helicase

An enzyme that unwinds the DNA double helix by breaking the hydrogen bonds between complementary base pairs during DNA replication.

DNA Ligase

An enzyme that joins together DNA fragments, particularly Okazaki fragments on the lagging strand, by forming phosphodiester bonds.

Messenger RNA (mRNA)

A type of RNA that carries genetic information from DNA in the nucleus to the ribosomes in the cytoplasm for protein synthesis.

Transfer RNA (tRNA)

A type of RNA that carries specific amino acids to the ribosome during translation, matching them to codons on the mRNA.

Ribosomal RNA (rRNA)

A type of RNA that is a primary structural and catalytic component of ribosomes, essential for protein synthesis.

Codon

A three-nucleotide sequence on an mRNA molecule that specifies a particular amino acid or a stop signal during protein synthesis.