Genetics, Meiosis, and Mutations Review

Comprehensive vocabulary flashcards covering human genetics, nucleic acid structure, molecular biology dogma, stages of meiosis, gametogenesis, chromosomal abnormalities, and genetic mutations.

Genome

The description of all the DNA present in a living organism.

Human Gene Count

Humans have approximately $120{,}000$ genes ($40$ active, $80$ not active).

Human Genetic Equality

The degree of genetic identity shared among all humans, which is $99.9\%$.

Somatic Cell

Every cell in the body (with exceptions); diploid cells that contain $2$ sets of chromosomes and undergo mitosis.

Germ Cell

Diploid cells located in reproductive organs that undergo meiosis to divide and turn into gametes.

Gametes

Haploid sex cells that fuse with each other at conception.

Diploid

Having two complete sets of chromosomes ($2n$).

Haploid

Having one single set of chromosomes ($n$).

Chromosome

A collection of genes consisting of thousands of genes per chromosome.

DNA

The molecule that chromosomes are made of; stores instructions for proteins and is passed down to offspring.

Gene

A single set of instructions used to make proteins for your body.

Histone

A protein structure that DNA wraps around to provide structural support.

Allele

Multiple alternate forms or versions of the same gene.

Genotype

The genetic makeup or appearance of an organism (e.g., the allele letters in genes).

Phenotype

The physical appearance or observable traits of an organism (e.g., hair colour, eye colour).

Homozygous Dominant

Carrying two identical dominant alleles for a given trait (e.g., DD).

Homozygous Recessive

Carrying two identical recessive alleles for a given trait (e.g., rr).

Heterozygous

Carrying two different alleles for a given trait (e.g., Rr).

Heredity

The transmission of traits passed down from parents to their offspring.

Reproduction

Cell division processes carried out to produce offspring.

Sexual Reproduction

The production of offspring resulting from the fusion of $2$ sex cells.

Asexual Reproduction

The production of offspring originating from a single parent.

Sister Chromatids

Genetically identical duplicated chromosomes joined together.

Coding DNA

Regions of DNA that make up genes consisting of specific, functional sequences of base pairs (A, C, T, G).

Non-Coding DNA

Regions of DNA that do not encode actual genetic instructions and consist of random base pairs (A, C, T, G).

Telomeres

Protective structures located at the physical ends of each chromosome.

Homologous Chromosomes

Pairs of matching chromosomes received from parents that carry the same genes at the same loci, but potentially different versions (alleles).

RNA

A nucleic acid molecule that takes instructions from DNA and passes them along to synthesize proteins.

Nucleotide

The basic building block monomer of DNA and RNA; composed of a phosphate group, a nitrogenous base, and a $5$-carbon sugar.

Hydrogen Bond

The chemical bond that holds complementary base pairs together in the DNA double helix.

Central Dogma

The directional pathway of genetic expression where DNA makes RNA, and RNA directs the synthesis of polypeptides.

mRNA

Messenger RNA; transports genetic instructions from DNA to the ribosomes.

tRNA

Transfer RNA; brings the correct amino acids to the ribosome during translation.

rRNA

Ribosomal RNA; forms structural and catalytic components of the ribosome, serving as the site of translation.

Transcription

The process of creating an RNA copy from DNA instructional strands.

Translation

The assembly of proteins where anticodons on tRNA match mRNA codons to join amino acids into a polypeptide chain.

Codon

A triplet sequence of $3$ bases located on mRNA that specifies an amino acid.

Anticodon

A triplet set of $3$ bases located on tRNA complementary to a corresponding mRNA codon.

Chemical Tags

Molecules that attach to and cover DNA and histones to protect and regulate genome activity.

Epigenetics

A flexible regulatory layer that alters genome structure by tightening wraps around inactive genes and relaxing wraps around active genes.

Epigenetic Profile

The comprehensive collection of chemical tags that determine whether specific genes are turned on or off.

Crossing Over

The exchange of genetic segments during synapsis in late prophase I or early metaphase I, producing mosaic chromosomes and increasing diversity.

Random Assortment

The independent and random distribution of maternal and paternal chromosomes during anaphase I and II of meiosis.

Spermatogenesis

The meiotic formation of male gametes producing $4$ small, viable sperm cells.

Oogenesis

The meiotic formation of female gametes resulting in $1$ large, nutrient-rich egg cell and $3$ polar bodies.

Polar Body

A non-functional haploid cell produced during unequal meiotic cytokinesis in oogenesis.

Uneven Cell Division

The asymmetric cytoplasmic division during oogenesis designed to concentrate maximum nutrients into a single healthy egg cell.

Karyotype

The complete chromosomal arrangement and set within the cells of an individual.

Autosomes

Any chromosome that is not a sex chromosome, consisting of chromosome pairs $1\text{--}22$ in humans.

Sex Chromosome

The $23\text{rd}$ pair of chromosomes that determines whether an organism is genetically male (XY) or female (XX).

Polydactyly

A congenital condition where an individual is born with extra fingers or toes.

Hypertrichosis

A genetic condition characterized by excessive hair growth over any region of the body.

Silent Mutation

A chromosomal or nucleotide alteration that produces no observable change in the organism's phenotype.

Germ Cell Mutation

A mutation occurring within germ cells that does not harm the parent but can be passed to future offspring.

Point Mutation

A gene mutation where a single base code error alters the translation of a codon.

Chromosomal Deletion

A structural mutation wherein a chromosomal fragment breaks off and is permanently lost.

Polyploidy

A chromosomal condition occurring when a cell fails to undergo the second meiotic division, resulting in a $3n$ organism.

Nondisjunction

An error during anaphase of meiosis characterized by the uneven splitting and failure of chromosomes to separate properly.

Trisomy

A condition in which a cell has $23$ chromosome pairs with one specific set containing $3$ chromosomes instead of two.

Monosomy

A condition in which a cell has $23$ chromosome pairs with one specific set containing only $1$ chromosome instead of two.

RNA polymerase

enzyme that builds mrna

DNA helicase

enzyme that unzips DNA