Genetics essential chapter 1-5

Genetics

The study of heredity and variation in living organisms.

Genome

The complete genetic material of an organism.

Transmission genetics

Study of how traits are inherited between generations.

Molecular genetics

Study of DNA structure and gene function.

Population genetics

Study of genetic variation within populations.

Model genetic organism

A species widely studied to understand genetic principles.

Pangenesis

Incorrect theory that traits originate from all body parts.

Inheritance of acquired characteristics

Incorrect idea that traits acquired during life are inherited.

Preformationism

Incorrect theory proposing miniature organisms in gametes.

Blending inheritance

Incorrect theory that parental traits blend permanently.

Cell theory

All living organisms are composed of cells.

Germ-plasm theory

Only reproductive cells transmit genetic information.

Prokaryote

A cell lacking a nucleus and membrane-bound organelles.

Eukaryote

A cell containing a nucleus and membrane-bound organelles.

Bacteria

Single-celled prokaryotic organisms.

Archaea

Prokaryotes genetically distinct from bacteria.

Nucleus

Membrane-bound organelle containing genetic material.

Histone

Protein around which DNA is wrapped.

Chromatin

DNA and proteins forming chromosomes.

Virus

Noncellular genetic entity requiring a host.

Homologous pair

Two chromosomes with the same genes.

Diploid

Cell with two chromosome sets.

Haploid

Cell with one chromosome set.

Polyploid

Cell with more than two chromosome sets.

Centromere

Region joining sister chromatids.

Telomere

Protective chromosome ends.

Origin of replication

DNA replication start site.

Sister chromatid

One of two identical chromosome copies.

Cell cycle

Sequence of cell growth and division.

Checkpoint

Cell cycle control point.

Interphase

Cell growth and DNA replication phase.

M (mitotic) phase

Phase including mitosis and cytokinesis.

Mitosis

Division of the nucleus.

Cytokinesis

Division of cytoplasm.

Prophase

Chromosomes condense.

Condensin

Protein complex that compacts chromosomes.

Prometaphase

Nuclear envelope breaks down.

Metaphase

Chromosomes align at metaphase plate.

Anaphase

Sister chromatids separate.

Telophase

Nuclei reform.

Interkinesis

Rest phase between meiosis I and II.

Prophase II

Chromosomes condense in haploid cells.

Metaphase II

Chromosomes align in meiosis II.

Anaphase II

Sister chromatids separate in meiosis II.

Telophase II

Haploid nuclei reform.

Recombination

Formation of new allele combinations.

Cohesin

Protein holding sister chromatids together.

Spermatogenesis

Process of sperm formation.

Spermatogonium

Diploid male germ cell.

Primary spermatocyte

Diploid cell entering meiosis I.

Secondary spermatocyte

Haploid cell after meiosis I.

Spermatid

Immature haploid sperm cell.

Oogenesis

Process of egg formation.

Oogonium

Diploid female germ cell.

Primary oocyte

Diploid cell arrested in prophase I.

Secondary oocyte

Haploid cell after meiosis I.

First polar body

Small haploid cell from meiosis I.

Second polar body

Small haploid cell from meiosis II.

Microsporocyte

Diploid plant cell producing microspores.

Microspore

Haploid male plant gametophyte.

Megasporocyte

Diploid plant cell producing megaspores.

Megaspore

Haploid female plant gametophyte.

Gene

Unit of heredity encoding a product.

Allele

Alternative form of a gene.

Locus

Physical location of a gene.

Genotype

Genetic makeup of an organism.

Phenotype

Observable characteristics.

Homozygous

Two identical alleles.

Heterozygous

Two different alleles.

Monohybrid cross

Cross involving one gene.

P generation

Original parental generation.

F1 generation

First filial offspring generation.

F2 generation

Second filial offspring generation.

Reciprocal cross

Cross with parental sexes reversed.

Dominant

Expressed allele.

Recessive

Masked allele.

Principle of segregation

Alleles separate during gamete formation.

Concept of dominance

Dominant allele determines phenotype.

Chromosome theory of heredity

Genes reside on chromosomes.

Backcross

Cross between F1 and parent.

Punnett square

Predictive grid.

Probability

Likelihood of an outcome.

Multiplication rule

Probability of independent events both occurring.

Addition rule

Probability of mutually exclusive events.

Testcross

Cross with homozygous recessive.

Wild type

Most common phenotype.

Dihybrid cross

Cross involving two genes.

Principle of independent assortment

Genes assort independently.

Chi-square test

Compares observed and expected ratios.

Pedigree

Family inheritance diagram.

Proband

Individual initiating pedigree.

Consanguinity

Mating between close relatives.

Sex determination

Biological determination of sex.

Sex chromosome

Chromosome determining sex.

Autosome

Non-sex chromosome.

Heterogametic sex

Produces two gamete types.

Homogametic sex

Produces one gamete type.

X-linked characteristic

Trait on X chromosome.

Y-linked characteristic

Trait on Y chromosome.

Hemizygosity

Single gene copy.