Bio Topic 2

Cell Cycle

Series of phases for cell growth and division.

Interphase

90% of cell cycle; includes G1, S, G2.

G1 Phase

Cell grows and produces proteins and organelles.

S Phase

DNA replication occurs, forming sister chromatids.

G2 Phase

Cell prepares for mitosis and checks DNA.

Mitotic Phase

10% of cell cycle; includes mitosis and cytokinesis.

Mitosis

Division of the nucleus into two nuclei.

Cytokinesis

Division of cytoplasm, forming two daughter cells.

G1 Checkpoint

Checks for DNA damage and resources availability.

G2 Checkpoint

Ensures successful DNA replication before mitosis.

M Checkpoint

Verifies chromosome alignment during mitosis.

Cyclins

Proteins regulating progression through the cell cycle.

CDKs

Enzymes that activate cyclins for cell cycle control.

Tumor Suppressor Genes

Prevent uncontrolled cell division, aiding cancer prevention.

DNA Replication

Process of copying DNA during S phase.

Helicase

Enzyme that unwinds DNA double helix.

Topoisomerase

Prevents DNA overwinding ahead of replication fork.

Primase

Adds RNA primers to initiate DNA synthesis.

DNA Polymerase

Enzyme adding nucleotides to growing DNA strand.

Leading Strand

Synthesized continuously in 5' to 3' direction.

Lagging Strand

Synthesized in Okazaki fragments, discontinuously.

Genome

Complete set of an organism's DNA.

Eukaryotic Genome

Multiple linear chromosomes located in the nucleus.

Prokaryotic Genome

Single circular chromosome located in cytoplasm.

Chromatin

Complex of DNA and proteins (histones).

Sister Chromatids

Identical chromosome copies joined at centromere.

Telomeres

Protective ends of chromosomes that shorten with age.

Meiosis

Process creating haploid gametes from diploid cells.

Meiosis I

Separates homologous chromosomes into haploid cells.

Prophase I

Homologous chromosomes pair and exchange DNA.

Metaphase I

Homologous pairs align at the metaphase plate.

Anaphase I

Homologous chromosomes separate to opposite poles.

Telophase I

Two haploid cells form after chromosome separation.

Meiosis II

Separates sister chromatids, similar to mitosis.

Crossing Over

Exchange of genetic material between homologous chromosomes.

Independent Assortment

Random distribution of chromosomes during meiosis.

Random Fertilization

Any sperm can fertilize any egg, increasing diversity.

Viral Replication

Process by which viruses replicate inside a host.

Lytic Cycle

Virus replicates quickly, destroying host cell.

Lysogenic Cycle

Virus integrates into host genome, remains dormant.

RNA Virus

Uses RNA-dependent RNA polymerase for replication.

DNA Virus

Uses host DNA polymerase for replication.

Retrovirus

Uses reverse transcriptase to convert RNA to DNA.