DNA and Genetics Vocabulary Practice

A set of vocabulary flashcards covering DNA structure, replication, chromosomal organization, inheritance, and cell division based on the lecture notes.

DNA

Short for Deoxyribonucleic Acid; a molecule that carries genetic instructions.

Nucleotides

The building blocks of DNA, consisting of a phosphate group, a deoxyribose sugar, and a nitrogenous base.

DNA replication

The process of copying DNA to produce an identical strand.

Helicase

An enzyme involved in DNA replication that unwinds and unzips the DNA double helix.

DNA Polymerase

An enzyme that pairs free nucleotides with the template strand during DNA replication.

Ligase

An enzyme that seals the sugar-phosphate backbone during DNA replication.

Autosomes

Chromosome pairs $1$–$22$ in humans that code for body characteristics and non-sex traits.

Sex chromosomes

The $23^{rd}$ pair of chromosomes (either $XX$ or $XY$) that determine biological sex and sex-linked traits.

Diploid ($2n$)

A cell containing two sets of chromosomes, one from each parent; in humans, the diploid number is $46$.

Haploid ($n$)

A cell containing a half set of chromosomes; in humans, the haploid number is $23$.

Gamete

Specialized sex cells, such as sperm in males and eggs (ovum) in females, that carry $23$ chromosomes.

Zygote

A cell with $46$ chromosomes formed during fertilisation when a sperm and egg combine.

Sexual reproduction

A process involving two parents that combines genetic information to produce non-identical offspring.

Asexual reproduction

A process involving one parent that produces genetically identical offspring.

Mitosis

A type of cell division for growth and repair that results in $2$ identical diploid daughter cells.

Meiosis

A type of cell division that produces $4$ different haploid gametes and involves crossing over during Prophase $I$.

Mutation

A change in the DNA sequence.

Point mutation

A type of mutation where one single nitrogenous base is changed or swapped.

Frameshift mutation

A type of mutation caused by an insertion or deletion that shifts the reading frame of the DNA.

Mutagen

Anything that causes mutations in DNA, classified into chemical (e.g., cigarette smoke), physical (e.g., $UV$ rays), or biological (e.g., viruses) types.

Phenotype

The observable characteristics or physical traits of an organism.

Genotype

The combination of alleles present in an organism for a specific trait.

Dominant alleles

Alleles represented by capital letters (e.g., $A$, $B$, $H$) that mask the presence of recessive alleles.

Recessive alleles

Alleles represented by lowercase letters (e.g., $a$, $b$, $h$) that only show their trait when two are present ($homozygous$ $recessive$).

Homozygous

A genotype consisting of two of the same alleles, such as $AA$ or $aa$.

Heterozygous

A genotype consisting of two different alleles, such as $Aa$.

Carrier female

An individual with the genotype $X^B X^b$ who is not affected by a sex-linked trait but can pass the gene to offspring.