Cell Communication and the Cell Cycle

These flashcards cover key concepts from the lecture on cell communication and the cell cycle, including the functions of various signaling mechanisms and their implications for cell behavior.

What is the main function of cell signaling in yeast during mating?

Cell signaling allows yeast cells to communicate and mate by releasing a mating factor that binds to receptors on other yeast cells.

What do genetically engineered yeast cells producing only mating factor α indicate about their mating behavior?

They will mate with normal mating type a cells, but not with normal mating type α cells.

In the context of biofilms, what is the primary function of cell signaling?

Aggregation of bacteria that can potentially cause cavities.

What is paracrine signaling?

A type of local signaling where a cell secretes a signal molecule that affects neighboring cells.

What is required for a target organ to respond to a hormone?

The target organ must have receptors that recognize and bind the hormone.

How do plant hormones differ from animal hormones?

Plant hormones can travel through the air as a gas.

What part of the signal pathway does a neurotransmitter serve when opening gated ion channels?

The neurotransmitter acts as a signal molecule.

What type of signaling does a receptor tyrosine kinase engage in?

It functions by forming dimers, adding phosphate groups, and activating relay proteins.

What is the primary role of scaffolding proteins in signal transduction?

They attach several relay proteins to facilitate cascade effects.

What does a G protein need to be in its active state?

A G protein bound to GTP is in its active state.

How is the phycological effect of testosterone explained?

Testosterone binds with a receptor protein that enters the nucleus and activates gene expression.

What occurs during apoptosis?

The cell's DNA and organelles become fragmented, the cell shrinks, and its parts are packaged in vesicles for digestion.

What can lead to intense signaling in cancer cells?

Excessive levels of receptor tyrosine kinases promoting cell division can lead to cancer.

What evidence suggests the evolutionary significance of cell signaling pathways?

Cell-signaling pathways are seen in primitive cells like bacteria and yeast.

How do lipid-soluble signaling molecules like aldosterone affect target cells?

Only target cells contain intracellular receptors for aldosterone.

What does it mean when a signal is said to be transduced?

The physical form of the signal changes as it passes from the cell membrane to intracellular targets.

What is the role of phosphatases in signal transduction pathways?

They inactivate protein kinases to turn off signal transduction.

What happens to MPF during mitosis?

The cyclin component of MPF is degraded.

How do cyclin-dependent kinases (Cdks) function in the cell cycle?

They are inactive until bound to cyclin, leading to phosphorelation of target proteins.

What prevents a cell from dividing when it has an abnormal number of chromosomes?

Cell cycle checkpoints ensure cells with chromosome abnormalities do not progress.

What happens at the G2 checkpoint of the cell cycle?

The cell is checked for DNA damage and accurate DNA replication before entering mitosis.