AP Bio Cell Cycle, Mitosis, Meiosis & Heredity Study Guide’23

G1 Phase

The first phase of the cell cycle where the cell grows and prepares for DNA replication.

S Phase

The phase of the cell cycle where DNA synthesis and replication occur.

G2 Phase

The phase of the cell cycle following DNA synthesis, where the cell prepares for mitosis.

Prophase

The first stage of mitosis where chromatin condenses into visible chromosomes.

Metaphase

The second stage of mitosis where chromosomes line up along the equatorial plane of the cell.

Anaphase

The third stage of mitosis where sister chromatids are pulled apart to opposite poles of the cell.

Telophase

The final stage of mitosis where chromosomes de-condense and nuclear envelopes reform.

Cytokinesis

The process that divides the cytoplasm of a parental cell into two daughter cells.

Cell Cycle Checkpoints

Regulatory mechanisms in the cell cycle that assess whether the cell is ready to proceed to the next stage.

MPF Kinases

M-phase promoting factor, a complex that regulates the transition from the G2 phase to mitosis.

Density-Dependent Inhibition

A regulatory mechanism that stops cell division when cells become crowded.

Growth Factors

Proteins that stimulate cell growth and division.

G0 Phase

A resting phase where the cell is neither dividing nor preparing to divide.

Cancer

A disease characterized by uncontrolled cell growth and division.

Apoptosis

Programmed cell death that occurs in multicellular organisms.

Proto-Oncogenes

Normal genes that, when mutated, can become oncogenes and drive cancer progression.

Oncogenes

Mutated genes that have the potential to cause cancer, such as RAS and AKT.

Tumor Suppressor Genes

Genes that protect a cell from one step on the path to cancer, such as p53 and BRCA-1.

Signal Reception

The first step in cell signaling where a cell detects a signaling molecule.

Signal Transduction

The process by which a signal received by a cell leads to a cellular response.

Response (in cell signaling)

The final step in cell signaling, typically resulting in changes such as gene expression.

Mitosis

A process of cell division that results in two identical daughter cells, essential for growth, repair, and replacement.

Meiosis

A specialized form of cell division that produces gametes (sex cells) with half the chromosome number.

Haploid

A cell that contains a single set of chromosomes (n).

Diploid

A cell that contains two sets of chromosomes (2n).

Gamete

A mature reproductive cell such as a sperm or egg.

Zygote

The fertilized egg that results from the union of sperm and egg.

Oogenesis

The process of egg cell (ovum) formation through meiosis in females.

Spermatogenesis

The process of sperm cell formation through meiosis in males.

Law of Segregation

Mendel's principle that alleles for a trait segregate during gamete formation.

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during cell division.

Synapsis

The pairing of homologous chromosomes during prophase I of meiosis.

Crossing Over

The exchange of genetic material between homologous chromosomes during prophase I, increasing genetic diversity.

Gene Map Units

A unit measuring the frequency of recombination between genes, where 1 mu = 1% crossing over frequency.

Law of Independent Assortment

Mendel's principle stating that alleles of different genes assort independently of one another during gamete formation.

Random Fertilization

The random combination of gametes during fertilization, contributing to genetic variation.

Phenotype

The observable traits of an organism resulting from the interaction of its genotype with the environment.

Genotype

The genetic constitution of an organism, represented by the alleles present.

Allele

Different forms of a gene that can exist at a specific locus.

Homozygous

An individual having two identical alleles for a particular gene.

Heterozygous

An individual having two different alleles for a particular gene.

Recessive Trait

A trait that is expressed in the phenotype only when two recessive alleles are present.

Sex-linked Inheritance

Inheritance of traits determined by genes located on sex chromosomes.

Codominance

A pattern of inheritance in which both alleles in a heterozygote are fully expressed.

Incomplete Dominance

A form of inheritance where the phenotype of heterozygotes is intermediate between the phenotypes of the homozygotes.

Polygenic Traits

Traits that are controlled by multiple genes, leading to a continuous range of phenotypes.

Monohybrid Cross

A genetic cross that examines the inheritance of a single characteristic.

Dihybrid Cross

A genetic cross that examines the inheritance of two different traits.

Expected Phenotypic Ratios

Predicted ratios of phenotypes in offspring resulting from genetic crosses, such as 3:1 in monohybrid crosses.