Unit 4: Cell Communication and Cell Cycle FLASHCARDS

Taxis

Movement in response to a stimulus.

Chemotaxis

Movement in response to chemical signals.

Signal Transduction

Transmission of external signals into a cell.

Ligands

Signaling molecules that bind to receptors.

Plasma Membrane Receptors

Integral proteins transmitting signals into cells.

Ligand-gated Ion Channels

Open upon ligand binding, allowing ion flow.

Catalytic Receptors

Enzyme-linked receptors activating upon ligand binding.

G-protein-linked Receptors

Bind G-proteins, activating secondary messengers.

Cyclic AMP (cAMP)

Important second messenger in signal transduction.

Homeostasis

Conditions allowing survival of living organisms.

Negative Feedback Pathway

Inhibits process using the end product.

Positive Feedback Pathway

Stimulates process using the end product.

Cell Cycle

Life cycle from one cell division to next.

Interphase

Growing phase between cell divisions.

S Phase

Phase where DNA is replicated.

Sister Chromatids

Identical DNA strands held together by centromere.

Cell Cycle Checkpoints

Control mechanisms ensuring proper cell division.

Cyclins

Proteins regulating cell cycle progression.

Cyclin-dependent Kinases (CDKs)

Enzymes activated by cyclins to progress cell cycle.

Apoptosis

Programmed cell death due to irreparable damage.

Oncogenes

Mutated genes converting normal cells to cancerous.

Proto-oncogenes

Healthy versions of genes that can become oncogenes.

Tumor Suppressor Genes

Prevent conversion of normal cells into cancer cells.

Mitosis

Cell division occurring in four stages.

Prophase

Nuclear envelope disappears; chromosomes condense.

Metaphase

Chromosomes align at the metaphase plate.

Anaphase

Chromosomes are pulled away from the center.

Telophase

Formation of two new nuclei ends mitosis.

Cytokinesis

Cytoplasm divides, forming two daughter cells.

Chromatin

Decondensed genetic material after mitosis.

Purpose of Mitosis

Produces identical daughter cells for growth or repair.