Genetic Control of Cell Function and Inheritance – Vocabulary Flashcards (Chapter 4–5 Notes)

Vocabulary flashcards covering key genetic concepts, terms, and inheritance patterns from the notes.

Allele

A variant form of a gene; example: ABO alleles (A, B, O) with multiple genotypes (AA, AO, BB, BO, AB, OO).

Chromatin

A tightly coiled mixture of DNA, proteins, and a small amount of RNA; framework for chromosomes.

Chromosomes

Bar-like bodies of chromatin; humans have 46 (23 pairs).

DNA (deoxyribonucleic acid)

Molecule storing genetic information; located in the nucleus; ~3 billion nucleotides in humans.

Gene

A short section of DNA that encodes a functional product, usually a protein.

Genome

Complete set of DNA in an organism; the full “owner’s manual.”

Genetics

The study of genes and their function.

Heterozygous

Having two different alleles at a locus (e.g., Aa).

Histones

Major proteins in chromatin that help package DNA.

Homozygous

Having the same allele at a locus on both chromosomes (e.g., AA or aa).

Karyotype

An individual’s complete set of chromosomes.

Locus

The fixed position of a gene on a chromosome.

Proteome

The complete set of proteins encoded by the genome.

Proteomics

The study of proteomes.

RNA (ribonucleic acid)

Single-stranded molecule essential in coding, decoding, regulation, and expression of genes.

Exon

Protein-coding region of a gene in mRNA.

Intron

Non-coding region of a gene that is removed during mRNA processing.

Splicing

Editing of mRNA to join exons together, enabling diverse protein products.

mRNA (messenger RNA)

RNA copy of a gene used as a template for protein synthesis.

Transcription

Process by which RNA polymerase uses DNA as a template to synthesize mRNA in the nucleus.

Translation

Process by which ribosomes read mRNA codons to assemble amino acids into a protein.

Codon

A three-nucleotide sequence in mRNA that specifies an amino acid.

tRNA

RNA that transports specific amino acids to the ribosome during protein synthesis.

Peptide bond

Chemical bond linking amino acids in a growing polypeptide chain.

Polypeptide

A chain of amino acids that folds into a protein.

Gene Expression

The degree to which a gene is transcribed and translated into a protein.

Gene Induction

Increased gene expression.

Gene Repression

Decreased gene expression.

Transcription factors

Proteins that bind DNA and regulate transcription.

Epigenetics

Study of how environment/behavior alter gene expression without changing DNA sequence.

DNA methylation

Addition of methyl groups to DNA, often repressing gene expression.

Histone acetylation

Addition of acetyl groups to histones, opening chromatin and turning genes on.

Histone methylation

Addition of methyl groups to histones, often turning genes off.

Non-coding RNA

RNA molecules that do not encode proteins but regulate gene expression.

Epigenetic modification

Chemical changes to DNA or histones that affect gene expression without changing sequence.

Genotype

An individual’s genetic makeup (DNA sequence) at a given locus.

Phenotype

Visible or measurable characteristics resulting from gene expression and environment.

Carrier

A person with a recessive allele who does not express the phenotype but can pass the allele to offspring.

Penetrance

The proportion of individuals with a genotype who actually express the phenotype.

Expressivity

The range (mild to severe) of phenotype expressed by a genotype.

Autosomal dominant

A disorder caused by one mutant allele on an autosome; affected offspring have 50% risk to inherit.

Autosomal recessive

Disorder requiring two copies of a mutant autosomal allele; carrier parents may have affected children.

X-linked recessive

Disorder on the X chromosome typically affecting males; females usually carriers.

X-linked dominant

Disorder on the X chromosome that can affect both sexes; often more severe in males.

Marfan syndrome

Autosomal dominant connective tissue disorder with skeletal, ocular, and cardiovascular abnormalities.

Neurofibromatosis

Autosomal dominant disorder (NF-1) with neurofibromas and café au lait spots.

Phenylketonuria (PKU)

Autosomal recessive metabolic disorder due to phenylalanine hydroxylase deficiency; severe cognitive effects if untreated.

Tay-Sachs disease

Autosomal recessive lysosomal storage disorder causing neurodegeneration; fatal in early childhood.

Cystic fibrosis (CFTR)

Autosomal recessive disorder of exocrine glands, with thick mucus and pancreatic/respiratory issues due to CFTR mutation.

Turner syndrome

Numeric chromosomal disorder (45,X) with partial/complete absence of one X chromosome.

Klinefelter syndrome

Sex chromosome aneuploidy (47,XXY) in males leading to hypogonadism and other features.

Down syndrome

Chromosomal disorder (Trisomy 21) with intellectual disability and distinctive features.

Aneuploidy

Abnormal number of chromosomes (e.g., trisomy, monosomy) often from nondisjunction.

Nondisjunction

Failure of homologous chromosomes or sister chromatids to separate during meiosis.

Triploidy

Triplication to 69 chromosomes; a form of numeric chromosomal abnormality.

Punnett square

A grid used to predict the Genotype/Phenotype combinations of offspring from parental alleles.

Sickle cell disease

Autosomal recessive disorder caused by a mutated beta-globin gene; abnormal hemoglobin.