Comprehensive Heredity, Molecular Genetics, and Biology Flashcards

Vocabulary flashcards generated from the provided lecture notes covering genetics, biotechnology, diversity, organ systems, and evolution.

Sex-linked genes

Genes that reside specifically on a sex chromosome.

Sex-influenced genes

Genes whose expression can be affected by the sex of the individual carrying the trait.

Linkage map

A chromosome map that uses recombination frequency to show the relative positions of genes on a chromosome.

Linked genes

Genes that reside close together on a chromosome, making them less likely to be separated by recombination during meiosis and more likely to be inherited together.

X-inactivation

The process during embryonic development in female mammals where one of the two X chromosomes is inactivated, forming a highly condensed Barr body.

Aneuploidy

The occurrence of an abnormal number of extra or missing chromosomes in a cell, often caused by nondisjunction.

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during mitosis or meiosis, resulting in gametes with abnormal chromosome numbers.

Penetrance

The proportion of individuals with a specific genotype that express the corresponding phenotype.

Expressivity

The degree or variation of a phenotype expressed by a specific genotype.

Colchicine

A chemical agent that arrests mitosis by interfering with mitotic spindle formation, preventing cell replication.

Proto-oncogenes

Normal genes that stimulate cell growth and division, which can become cancer-causing oncogenes if mutated.

Tumor suppressor genes

Genes that code for proteins that help control and regulate cell growth, mutations in which may lead to cancer.

Chromosomal Inversion

A chromosomal aberration where a chromosome segment is rearranged in the reverse of its original orientation.

Chromosomal Translocation

A chromosomal aberration where a segment of a chromosome is moved to another non-homologous chromosome, which can be reciprocal or nonreciprocal.

DNA Polymerase III

An enzyme that synthesizes a new DNA strand in the $5' \rightarrow 3'$ direction by adding nucleotides to an existing RNA primer.

DNA Polymerase I

An enzyme in DNA replication that removes the RNA primer and replaces it with newly synthesized DNA nucleotides.

DNA Ligase

An enzyme that joins DNA fragments together by sealing gaps in the phosphodiester backbone between Okazaki fragments.

Helicase

An enzyme that untwists and separates the double-stranded DNA helix into single strands at the replication fork.

Topoisomerase

An enzyme that relieves the strain caused by DNA unwinding by breaking and rejoining DNA strands ahead of the replication fork.

Single-Stranded Binding Proteins

Proteins that bind to single-stranded DNA near the replication fork to prevent the two strands from re-annealing.

Promoter region

A specific sequence of DNA upstream of a gene where RNA polymerase attaches to initiate transcription.

Alternative splicing

A regulatory gene expression process during pre-mRNA splicing that allows a single gene to produce multiple distinct protein isoforms by combining different exons.

Silent mutation

A point mutation that changes a codon sequence without altering the encoded amino acid due to codon redundancy.

Missense mutation

A point mutation in which a single nucleotide change results in a codon that codes for a different amino acid.

Nonsense mutation

A point mutation that converts an amino acid codon into a stop codon, prematurely terminating translation to produce a truncated protein.

Frameshift mutation

A genetic mutation caused by the insertion or deletion of nucleotides not in multiples of three, shifting the reading frame of the transcript.

Operon

A functional unit of genomic DNA in prokaryotes containing a cluster of genes under the control of a single promoter, operator, and structural genes.

Bacterial Conjugation

The direct transfer of genetic material between two bacterial cells temporarily joined by a sex pilus.

Bacterial Transformation

The process by which a competent bacterium takes up naked, extracellular DNA from its surrounding environment.

Bacterial Transduction

The transfer of bacterial DNA from one host cell to another mediated by a virus called a bacteriophage.

Genome

The complete set of genetic material or nucleic acid sequences present in an organism.

Transcriptome

The entire set of RNA molecules transcribed by a specific cell, tissue, or organism.

Proteome

The complete set of expressed proteins produced by an organism, cell, or tissue type.

Polymerase Chain Reaction (PCR)

A biological technique used to amplify a specific DNA sequence through repeated cycles of denaturation, annealing, and elongation.

Reverse Transcriptase

An enzyme used to synthesize complementary DNA ($\text{cDNA}$) from an RNA template.

Southern Blotting

A laboratory method used to detect specific DNA sequences in a DNA sample.

Northern Blotting

A laboratory method used to detect specific RNA sequences to study gene expression.

Western Blotting

A laboratory technique used to detect and identify specific proteins in a tissue or cell extract.

Epigenetics

The study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than alteration in the underlying DNA sequence.

Genomic Imprinting

An epigenetic inheritance mechanism where a gene's expression depends strictly on whether it was inherited from the maternal or paternal parent.

Obligate Aerobes

Organisms that require oxygen to grow and survive through aerobic cellular respiration.

Obligate Anaerobes

Organisms that cannot survive in the presence of oxygen because oxygen is toxic to them.

Facultative Anaerobes

Organisms that generate ATP by aerobic respiration if oxygen is present, but can switch to anaerobic fermentation or respiration when oxygen is absent.

Gram-Positive Bacteria

Bacteria characterized by a thick peptidoglycan cell wall, lack of an outer membrane, absence of endotoxins, and staining purple during Gram staining.

Gram-Negative Bacteria

Bacteria characterized by a thin peptidoglycan cell wall, an outer lipopolysaccharide membrane, endotoxin production, and staining pink during Gram staining.

Mycelium

The vegetative part of a fungus, consisting of a network of fine white filaments called hyphae.

Coenocytic hyphae

Hyphae that lack septa cell walls and exist as continuous, multinucleated cellular threads.

Double Fertilization

A complex fertilization mechanism in angiosperms where one sperm fertilizes the egg cell to form a diploid ($2n$) zygote, and a second sperm fuses with two polar nuclei to form triploid ($3n$) endosperm.

Lytic Cycle

A viral reproductive cycle in which the virus infects the host cell, replicates new virions, and causes the host cell to burst and die.

Lysogenic Cycle

A viral reproductive cycle in which the viral genome integrates into the host cell's chromosome as a prophage and replicates passively alongside the host cell.

Prions

Infectious misfolded proteins that cause normal cellular proteins to misfold into the pathogenic prion form.

Viroids

Small, infectious, unencapsulated single-stranded circular RNA molecules that infect plant species.

Sodium-Potassium Pump

An active transport membrane mechanism that maintains a cell's resting potential at $-70\text{ mV}$ by exporting $3\text{ Na}^+$ ions out for every $2\text{ K}^+$ ions imported into the cell.

Sarcomere

The basic functional and contractile unit of a striated myofibril, defined as the region between two adjacent Z-lines.

Osteoblasts

Cells derived from osteoprogenitor lineages that synthesize collagen and organic bone matrix to build new bone.

Osteoclasts

Large, multinucleated cells derived from monocytes that break down and resorb bone matrix, releasing stored minerals like calcium into the blood.

Humoral immune response

An adaptive immune mechanism mediated by B-cell secreted antibodies that target and neutralize extracellular pathogens in body fluids.

Cell-mediated immune response

An adaptive immune mechanism driven by T cells that directly destroy infected or abnormal host cells.

Allopatric Speciation

The formation of new species from a parent population due to geographic isolation preventing gene flow.

Sympatric Speciation

The evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region.

Epistasis

A form of genetic interaction where the phenotypic expression of one gene is completely masked or altered by the presence of a distinct, independently inherited gene.

Pleiotropy

A genetic pattern where a single gene controls or influences multiple distinct phenotypic traits.

Polygenic Inheritance

The inheritance pattern of a phenotypic trait that is controlled by the additive effects of multiple independent genes.

Competitive inhibition

A type of enzyme inhibition where an inhibitor binds directly to the active site of the enzyme, increasing $K_m$ while leaving $V_{\text{max}}$ unchanged.

Noncompetitive inhibition

A type of enzyme inhibition where an inhibitor binds to an allosteric site rather than the active site, reducing $V_{\text{max}}$ while leaving $K_m$ unchanged.