Comprehensive Study Notes on Cell Division and Genetics

All organisms are made of one or more cells; cells are the basic unit of life; cells come from pre-existing cells.

Cell Theory

The amount of cell membrane available compared to the cell's volume. A larger ratio allows more efficient transport of nutrients and wastes.

Surface Area-to-Volume Ratio (SA:V)

The process by which cells create new cells for growth, repair, and reproduction.

Cell Division

The stage of the cell cycle when the cell grows, performs normal functions, and replicates DNA.

Interphase

First stage of interphase where the cell grows and organelles increase in number.

G1 Phase

Stage of interphase when DNA is copied.

S Phase

Stage of interphase when the cell prepares for mitosis.

G2 Phase

Division of the nucleus that produces two genetically identical nuclei.

Mitosis

Division of the cytoplasm that separates one cell into two daughter cells.

Cytokinesis

The longest stage of the cell cycle where growth, protein synthesis, and DNA replication occur.

Interphase

Long, uncoiled DNA found in the nucleus during interphase.

Chromatin

One of two identical copies of a chromosome

Chromatid

The region that joins two sister chromatids together

Centromere

Structures found in animal cells that help organize spindle fibers during mitosis

Centrioles

Microtubules that attach to chromosomes and move them during cell division

Spindle Fibres

first phase of mitosis where chromosomes condense and become visible

Prophase

Phase of mitosis where chromosomes line up along the center of the cell

Metaphase

Phase of mitosis where sister chromatids separate and move to opposite poles

Anaphase

Final phase of mitosis where new nuclear membranes form around chromosomes

Telophase

Acronym used to remember the stages of mitosis

PMAT

Cell division that produces four genetically unique haploid cells

Meiosis

Cells containing one set of chromosomes

Haploid (n)

Cells containing two sets of chromosomes

Diploid (2n)

Matching chromosome pairs, one from each parent

Homologous Chromosomes

Exchange of genetic material between homologous chromosomes during meiosis

Crossing Over

Random arrangement of homologous chromosomes during meiosis that increases variation

Independent Assortment

Failure of chromosomes to separate properly during meiosis

Non-Disjunction

A condition in which a cell has an abnormal number of chromosomes

Aneuploidy

Having an extra copy of a chromosome

Trisomy

Having only one copy of a chromosome

Monosomy

Scientist known as the "Father of Genetics" for his pea plant experiments

Gregor Mendel

Different forms of the same gene.

Alleles

An allele that masks the expression of another allele

Dominant Allele

An allele that is only expressed when two copies are present

Recessive Allele

The genetic makeup of an organism

Genotype

The observable characteristics of an organism

Phenotype

Organism with two identical alleles for a trait

Homozygous

Organism with two different alleles for a trait

Heterozygous

Diagram used to predict offspring genotypes and phenotypes

Punnett Square

Cross involving one trait

Monohybrid Cross

Traits controlled by genes located on the sex chromosomes

Sex-Linked Traits

Chromosomes that determine biological sex

Sex Chromosomes

Chromosomes that are not sex chromosomes

Autosomes

Why are small cells more efficient than large cells?

They have a larger surface area-to-volume ratio

What are the three main purposes of cell division?

Growth, repair/replacement, and reproduction

What stage of the cell cycle is DNA replicated?

S Phase

What does PMAT stand for?

Prophase, Metaphase, Anaphase, Telophase