Genetics test 3

Vocabulary flashcards covering key terms and concepts in molecular biology.

Nucleotide

The basic building block of nucleic acids, consisting of a base, a sugar, and a phosphate group.

Nucleoside

A structure consisting of a base and a sugar, without the phosphate group.

Purines

A class of nitrogenous bases that includes adenine (A) and guanine (G).

Pyrimidines

A class of nitrogenous bases that includes cytosine (C), thymine (T), and uracil (U).

Chargaff’s rule

The principle that in DNA, the amount of adenine equals that of thymine, and the amount of cytosine equals that of guanine.

Complimentary chain

A strand of nucleotides that can base pair with a given strand of nucleotides in DNA or RNA.

Base stacking

The stabilizing interaction between adjacent bases in the DNA double helix.

Major groove

The larger of the two grooves in the DNA double helix, where proteins often bind.

Minor groove

The smaller of the two grooves in the DNA double helix.

Methylation

The addition of a methyl group to DNA, which can affect gene expression.

Phosphodiester bond

A covalent bond that connects the sugar and phosphate groups of adjacent nucleotides.

Base pairs

Pairs of nucleotides in DNA that are connected by hydrogen bonds.

Transposable element

Segments of DNA that can move or be copied from one location to another in the genome.

Intergenic region

DNA sequences located between genes.

Sequence complexity

A measure of the amount of unique sequence information in a sample of DNA.

Topoisomerase

Enzymes that help relieve the strain of twisting in DNA by cutting and rejoining DNA strands.

Topoisomers

Different forms of the same DNA molecule that have varying degrees of supercoiling.

Microdomain

Small regions of genomic organization within a cell nucleus.

Macrodomain

Larger regions of genomic organization that may contain multiple microdomains.

Nucleoid

The region in prokaryotic cells where DNA is located.

Nucleosome

The basic unit of DNA packaging consisting of a segment of DNA wound around a core of histone proteins.

Loop domain

A segment of DNA that forms a loop by being tethered to the nucleoid.

DNA gyrase

An enzyme that introduces supercoils into DNA.

Introns

Non-coding segments of DNA that are removed during RNA splicing.

Exons

Coding segments of DNA that are included in the final RNA product.

Inverted repeats

Sequences of DNA that are inverted complements of one another.

Autonomous element

Transposable elements that can move independently within the genome.

Non-autonomous element

Transposable elements that cannot move without the help of autonomous elements.

Transposition

The process by which a transposable element moves within the genome.

Reverse transcriptase

An enzyme that converts RNA into DNA.

Integrase

An enzyme that facilitates the integration of viral DNA into the host genome.

LINEs

Long interspersed nuclear elements, a type of non-LTR retrotransposon.

SINEs

Short interspersed nuclear elements, non-coding RNA sequences in the genome.

Exon shuffling

The rearrangement of exons, leading to the creation of new genes.

Hybrid dysgenesis

A phenomenon in which hybrid offspring exhibit unusual genetic traits due to transposons.

LTRs

Long terminal repeats that are found in retrotransposons.

Simple transposons

Transposable elements that move without replicating.

Retrotransposons

Transposable elements that replicate via an RNA intermediate.

Zigzag model

A model describing the structure of chromatin fibers.

SMC protein

Structural Maintenance of Chromosomes proteins that are involved in chromosome organization.

CCCTC binding

A sequence recognized by specific transcription factors, affecting gene expression.

Condensin I

A protein complex involved in chromosome condensation during mitosis.

Condensin II

A protein complex that also plays a role in chromatin organization.

Cohesin

A protein that holds sister chromatids together after DNA replication.

Histone

Proteins that package and order DNA into structural units called nucleosomes.

Heterochromatin

Tightly packed form of DNA; transcriptionally inactive.

Euchromatin

Less condensed form of chromatin; transcriptionally active.

Topologically associating domain

Regions of the genome that interact more frequently with themselves than with other regions.