Biology Olympiad Review

Flashcards covering cell signaling, cellular responses, cell organization, the cell cycle, mitosis, and meiosis.

Autocrine

Cell signaling itself

Juxtacrine

Cells signaling through gap junctions between two cells

Paracrine

Cell targets cells nearby

Endocrine

Cell targets distant cells through blood stream

Reception

Signaling molecule (ligand) is detected by a receptor on a cell’s surface

Transduction

Receptor protein is changed; conversion of the signal to specific cellular response through the changing of molecules (phosphorylation of proteins)

Response

Cellular response is triggered; examples are: catalysis by an enzyme, activation of genes, apoptosis

G Protein

Functions as a molecular switch that is either on or off, depending on which of two guanine nucleotides is attached, GDP or GTP

Signaling molecule binding

Causes two receptor monomers to associate closely with each other, forming a complex known as a dimer in a process called dimerization

Protein Kinase

A protein that transfers phosphate groups from ATP to a protein

Protein Phosphatases

Remove phosphate groups from proteins and have the ability to deactivate

Secondary Messengers

Non-protein water-soluble molecules or ions that amplify a signal

Cyclic AMP

Enzyme Adenylyl Cyclase converts ATP to cAMP

Common Cellular Responses

Regulation of gene expression and protein synthesis, Inhibition of proteins, Production of growth factors, Inducing of cell division, Apoptosis

Genome

Genetic information

Chromosomes

DNA molecules are packaged into structures

Chromatin

The entire complex of DNA and proteins that maintain structure

Somatic Cells

Body Cells

Gamete Cells

Sex Cells

Interphase

Accounts for 90% of the cell cycle

G1 and G2 (Gap Phases)

Intense metabolic activity and growth occurs during these phases

S Phase (Synthesis)

DNA is replicated

M Phase

The cell divides, contains mitosis and cytokinesis

Mitosis Prophase

Chromatin fibers condense into chromosomes. Nuclear envelope disappears. Mitotic spindle starts to form

Metaphase

Centrosomes separate to opposite sides of the cell. Chromosomes align on the metaphase plate which is equidistant between the spindle’s two poles

Anaphase

Two sister chromatids of each chromosome separate. Each chromatid becomes its own chromosome.

Telophase

Chromosomes become less condensed. Cell begins to divide

Cytokinesis

Cytoplasm fully divides

Cyclins and Kinases

Molecules that regulate the cell cycle

Cyclin-dependent Kinases (CDK)

In order to activate the kinases that drive the cell cycle, they must bind to a cyclin to not be inactive

CDK Activity

The CDK activity is determined by the concentration of cyclins