Physiology Flashcards: Gene Expression and Cell Signaling

Gene

A region of DNA that contains information to make proteins

Transcription factors

Proteins that activate or inactivate gene expression

Transcription

Process of copying DNA into pre-mRNA

Nucleus

Location of transcription

RNA polymerase

Enzyme that synthesizes RNA from DNA

mRNA

RNA read by ribosomes to create proteins

Introns

Noncoding segments removed from pre-mRNA

Exons

Coding sections kept during splicing

Translation

Process where mRNA directs protein synthesis

Ribosomes

Where translation occurs

Codon

Triplet of mRNA bases coding for an amino acid

tRNA

Delivers amino acids to ribosome

Anti-codon

Triplet on tRNA that binds mRNA codon

Post-translational modification

Protein folding and modification after translation

Ribonucleases

Enzymes that break down mRNA

Interphase

Phase of growth, protein synthesis, DNA duplication

Mitosis

Phase when chromosomes are separated

Cancer

Uncontrolled cell division disease

S phase

Sub-phase when DNA is duplicated

Checkpoints

Cell cycle control points

Apoptosis

Programmed cell death

G0 phase

Resting phase, not dividing

Sister chromatid

Two identical DNA molecules held at centromere

Chromatid

Condensed DNA molecule before division

Chromatin

Loose DNA wrapped around histones

Anaphase

Mitosis phase where chromatids are pulled apart

Telophase

Mitosis phase when new nuclei form

Prophase

Mitosis phase where spindle forms, nucleus dissolves

Metaphase

Mitosis phase where chromatids align at center

Cytokinesis

Division of cytoplasm during mitosis

Plasma

Extracellular fluid for blood cells

Interstitial fluid

Extracellular fluid that surrounds body tissue cells

Intracellular fluid

Fluid inside body cells

Diffusion

Passive movement of molecules from high to low concentration

Osmosis

Passive movement of water across a membrane

Channel proteins

Transporters that form water-filled passages

Carrier proteins

Transporters that bind substrates and change shape

Facilitated diffusion

Passive transport via carrier proteins down concentration gradient

Active transport

Active transport requiring ATP

Open

Channels that are usually open

Gated

Channels that open under specific conditions

Voltage-gated

Channels opened by voltage change

Chemically-gated

Channels opened by binding signal molecules

Antiport

Carrier moving solutes in opposite directions

Symport

Carrier moving solutes in same direction

Membrane potential

Difference in charge across membrane

Negatively

Charge of cell interior relative to exterior

Hyperpolarized

Effect of Cl- influx on membrane

Depolarized

Effect of Na+ influx on membrane

Repolarized

What happens after Na+ closes and K+ opens?

Chemical signal

Molecule secreted to signal other cells

Target cell

Cell that has receptors for signal

Gap junctions

Cytoplasmic bridges between adjacent cells

Contact-dependent signaling

Communication via membrane-bound receptors

Paracrine

Signal acting on nearby cells

Autocrine

Signal acting on same cell

Hormone

Signal traveling in blood to distant cells

Neurohormone

Neuron signal in bloodstream

Neurotransmitter

Fast, short-term neuron signal

Neuromodulator

Slow, prolonged neuron signal

Cytokine

Immune signal made by many cells

Signal transduction

Process of converting signal across membrane

Integrin receptor

Receptor affecting cytoskeleton

Receptor enzyme

Receptor that activates attached enzyme

G protein-coupled receptor

Receptor with 7 membrane-spanning domains

Receptor channel

Receptor that opens/closes ion channel