Cell Growth and Differentiation Biology exam revision

Vocabulary flashcards covering cell cycle regulation, apoptosis, cancer genetics, stem cells, and embryonic development.

Apoptosis

Programmed cell death, a vital process for replacing old or unnecessary cells.

Cell Cycle Checkpoints

Points in the cell cycle where mutations are found and fixed by cyclins and CDKs.

G1 Checkpoint

Occurs prior to DNA replication, checks for DNA damage, nutrient sufficiency, and normal cell size.

G2 Checkpoint

Checks DNA again for damage after replication, ensures replication occurred correctly, and checks cell size.

Mitosis Checkpoint

Verifies that the spindle is correctly attached at the kinetochore to ensure proper chromosome separation.

Kinetochore

Proteins on the centromere of sister chromatids where the spindle attaches during mitosis.

Apoptosis Key Roles

Protection against damaged cells, embryonic development sculpting, and balancing tissue size.

Positive signals in apoptosis

Necessary for continued survival of a cell.

Negative signals in apoptosis

Indicate the need to activate the apoptosis pathway.

Caspases

Enzymes activated during apoptosis that break down the mitochondria and nucleus.

Cytochrome c

A protein complex released by the mitochondria during apoptosis, activating caspase enzymes.

Blebs

Balloon-like outgrowths that form on the cell membrane during apoptosis which form apoptotic bodies.

Apoptotic bodies

Membrane-bound vesicles formed from blebs during apoptosis; cleared by phagocytes.

Intrinsic pathway (apoptosis)

Apoptosis pathway activated by intracellular signals.

Extrinsic pathway (apoptosis)

Apoptosis pathway activated by extracellular signals binding to death receptors.

Necrosis

Unprogrammed cell death due to trauma or injury, causing inflammation.

Proto-oncogenes

Genes that regulate cell division, growth, and apoptosis. Mutations that enhance their function can lead to cancer.

Tumour suppressor genes

Genes that slow down cell division, repair DNA mistakes, or signal cells to die. Often mutated or silenced in cancer.

p53 gene

Gene that activates when DNA damage is detected, halting the cell cycle or initiating apoptosis.

BRCA genes

Genes (BRCA1 and BRCA2) that suppress uncontrolled cell growth and repair DNA damage. Mutations increase cancer risk.

RB1 gene

A tumour suppressor gene that inhibits progression of the cell cycle; mutation leads to retinoblastoma.

Mutagen

An agent that induces or increases the frequency of mutation in DNA.

Oncogenes

Mutated proto-oncogenes that stimulate excessive cell division.

Carcinogen

A cancer-causing chemical, e.g., those found in tobacco smoke.

Teratogen

A chemical that causes physical defects in a developing embryo (e.g., thalidomide).

Physical mutagens

Mutations in DNA caused by physical factors, e.g., UV light, X-rays and nuclear radiation.

Biological mutagens

Viruses linked to mutations in DNA that cause cancer such as HPV, hepatitis B and Epstein-Barr virus.

Stem Cells

Undifferentiated cells with the potential to develop into many different kinds of cell.

Ectoderm

Outer tissue layer of embryo; forms outer covering of body.

Mesoderm

Middle tissue layer of an embryo.

Endoderm

Inner tissue layer of an embryo.

Differentiation

The process by which cells become specialized to perform specific functions.

Totipotent

Stem cells with the potential to create ANY type of cell.

Pluripotent

Stem cells that give rise to all types of cells in a foetus (but not the placenta).

Multipotent

Stem cells that give rise to cells that have a specific function, e.g. red blood cells, skin cells etc.

Therapeutic Cloning

Creating ES cells through somatic cell nuclear transfer.

Stem cell research potential

Treat stroke, spinal cord injury, burns, heart disease, diabetes, arthritis, Alzheimer’s disease, Parkinson’s disease, identify teratogens.