Genetics & Molecular Biology - Vocabulary Flashcards (Video Lecture)

A comprehensive set of vocabulary-style flashcards covering DNA, RNA, nucleotides, transcription, translation, mutations, gene regulation, and chromosome structure from the lecture notes.

DNA

Deoxyribonucleic acid; double-helix that stores genetic information; backbone composed of sugar-phosphate with bases A, T, C, G.

RNA

Ribonucleic acid; usually single-stranded; uses ribose sugar and bases A, U, C, G; acts in transcription and translation.

Nucleotide

Building block of nucleic acids; composed of a sugar, a phosphate group, and a nitrogenous base.

Phosphate group

Phosphate group connects sugars to form the sugar–phosphate backbone of nucleic acids.

Deoxyribose

Five-carbon sugar in DNA lacking one oxygen atom (compared to ribose in RNA).

Ribose

Five-carbon sugar in RNA; contains an extra hydroxyl group compared to deoxyribose.

Nitrogenous base

Nitrogen-containing base attached to the sugar in nucleotides (A, T/U, C, G).

Adenine (A)

Purine base; pairs with thymine in DNA or uracil in RNA.

Thymine (T)

Pyrimidine base in DNA; pairs with adenine.

Cytosine (C)

Pyrimidine base; pairs with guanine.

Guanine (G)

Purine base; pairs with cytosine.

Uracil (U)

Pyrimidine base in RNA; pairs with adenine (replaces thymine in RNA).

Purines

Double-ring nitrogenous bases: adenine (A) and guanine (G).

Pyrimidines

Single-ring bases: cytosine (C), thymine (T) in DNA, and uracil (U) in RNA.

Backbone

Sugar–phosphate chain that provides the structural framework of a nucleic acid.

Antiparallel

arrangement where DNA strands run in opposite 5'→3' and 3'→5' directions.

5' end

One end of a nucleic acid with a phosphate group on the 5' carbon.

3' end

Opposite end of a nucleic acid strand with a hydroxyl group on the 3' carbon.

Base pairing

Hydrogen-bonded pairing: A with T (DNA) or A with U (RNA); C with G.

Codon

A three-nucleotide sequence in mRNA that encodes an amino acid or a stop signal.

Anticodon

Three-nucleotide region on tRNA that pairs with a complementary mRNA codon.

Start codon

AUG; signals the start of translation and codes for methionine.

Stop codon

UAA, UAG, or UGA; signals termination of translation.

Genetic Code

The mapping from mRNA codons to amino acids and stop signals; nearly universal.

Transcription

Process of producing RNA from a DNA template; performed by RNA polymerase.

Translation

Synthesis of a protein from mRNA at the ribosome; involves tRNA and amino acids.

RNA polymerase

Enzyme that synthesizes RNA using DNA as a template; binds promoter regions.

Promoter

DNA sequence where RNA polymerase binds to initiate transcription.

Terminator

DNA sequence signaling the end of transcription.

mRNA

Messenger RNA; carries genetic code from DNA to the ribosome for translation.

tRNA

Transfer RNA; carries amino acids and has an anticodon that pairs with mRNA codons.

Ribosome

Molecular machine where translation occurs; reads mRNA codons and assembles amino acids.

Mutation

A change in the DNA sequence; can alter gene function or expression.

Substitution

Mutation where one base is replaced; can be missense or nonsense.

Insertion

Addition of one or more nucleotides in DNA; can cause a frameshift.

Deletion

Removal of nucleotides from DNA; can cause a frameshift.

Frameshift

Mutation from insertion/deletion not in multiples of 3; shifts the reading frame.

Synonymous substitution

Substitution that does not change the encoded amino acid (silent).

Non-synonymous substitution

Substitution that changes the encoded amino acid.

Operon

Cluster of genes in prokaryotes transcribed together as a unit.

Lac operon

Prokaryotic operon regulating lactose-digesting enzymes; regulated by a repressor and lactose.

Repressor

Protein that binds to the operator to block transcription; can be inactivated by inducers like lactose.

Promoter (prokaryotes)

DNA region where RNA polymerase binds to initiate transcription of an operon.

Operator

DNA segment bound by regulatory proteins to control transcription in prokaryotes.

Chromosome

DNA packaged with proteins (histones) in the nucleus; carries genes.

Histone

Protein around which DNA wraps to form nucleosomes; aids in packaging.

Chromatin

DNA–protein complex; condensed form during cell division.

Diploid

Cell or organism with two complete sets of chromosomes (2n in humans).

Autosomes

Non-sex chromosomes; humans have 22 pairs that are the same in both sexes.

Sex chromosomes

Chromosomes determining sex (X and Y in humans).

Karyotype

A visual display of an organism's chromosomes arranged by size and structure.

Homologous chromosomes

Pairs of chromosomes carrying the same genes; may have different alleles.

Allele

Alternative form of a gene.

Zygote

Fertilized egg; a diploid cell resulting from fertilization that begins development.

Mitosis

Cell division producing two genetically identical diploid daughter cells.

Meiosis

Cell division producing haploid gametes with genetic variation.