Ch. 8: Interphase and the beginning

Cell division

used to generate new cells that are identical to the parental cell

Single-celled organisms (like bacteria & protozoans), use cell division for

Reproduction and growth

Cell division is critical to the following functions:

Growth, repair, and replacing old cells

Smallest unit of life

Cells

DNA

Genetic information stored in this form

Genome

The complete set of genetic information in an organism

In prokaryotic cells, the genome:

It includes a large chromosome & smaller plasmids

In eukaryotic cells, the genome:

Includes pairs of chromosomes found in the cell’s nucleus, and a circular chromosome in both the mitochondria and chloroplasts

The centromere

A constricted region of a chromosome and plays a key role in helping the cell divide up its DNA during division

Main function of chromosome

The attachment of sister chromatids, and it is the site for the attachment of spindle fiber

Different species contain this amount of chromosomes in the nuclei of the cells

Different numbers in nuclei of cells

Chromosomes location

Nuclei of cells

Same species contain this amount of chromosomes in the nuclei of their cells

Same numbers in nuclei of cells

Most eukaryotic cells have how many copies of each chromosome

Two copies

Homologous chromosomes

“matching” pairs of chromosomes

One copy of each homologous chromosome come from:

each parent organism

Homologous chromosomes contain:

Same genes at the same position

Alleles

Different versions of the same gene

Different alleles lead to…

Synthesis of slightly different proteins, allowing a variation and biodiversity

Diploid cells (2n)

Cells have 2 of each chromosome, one from each parent

Somatic cells

All cells in the body EXCEPT sperm and eggs

Somatic cells are which type of cells

Diploids because they contain 2 of each chromosomes

Haploid cells (n)

Cells have 1 of each chromosome

Gamete cells

The cells used in sexual reproduction; eggs + sperm

Gamete cells are which type of cells

Haploids because they only contain 1 of each chromosome

Karyotype

Picture of a cell’s genome

interphase

Phase where cells spend 90% of their time growing, building proteins, and dulplicating organelles

Mitotic phase

Short period of time when the cell divides its genetic information then divides

G₁ (gap 1) checkpoint

Cell builds proteins and ATP to prepare for the process of DNA replication.

Presence of growth factors in the environment around the cell.

G₀ (gap 0)

Resting stage cells are mostly in where normal cellular functions occur

S phase (Synthesis)

DNA is duplicated, generating X-shaped chromosomes made of two identical sister chromosomes

G₂ (gap 2) checkpoint

Organelles are duplicated. ATP is produced in preparation for mitosis and cytokinesis, along with cell size, DNA replication or damage