Anatomy and Physiology: Chapter 2: Cells & Chemistry

Diffusion

Passive movement of a substance from high to low concentration

Facilitated Diffusion

Passive movement of polar substances/ions requiring a transmembrane protein channel helper.

Osmosis

A special case of diffusion; the passive movement of free water molecules across a semipermeable membrane toward a higher concentration of solutes

Hypotonic Solution

Outside fluid has fewer solutes than the cytoplasm. Water rushes into the cell, causing it to bloat and pop (lysis).

Isotonic Solution

Outside fluid has the same solute level as the cytoplasm. Water moves evenly in and out; the cell retains normal shape.

Hypertonic Solution

Outside fluid has more solutes than the cytoplasm. Water rushes out of the cell, causing it to shrivel up (crenation).

Plasma Membrane Structure

An asymmetric amphiphilic phospholipid bilayer with a hydrophobic core.

Regulated what enters and exits the cell

Cholesterol

Molecules tucked inside the lipid bilayer that contribute to the fluidity of the cell membrane.

Integral Membrane Proteins

Embedded straight through the membrane (transport channels).

Peripheral Membrane Proteins

Loosely tuck only on the inner or outer surface (anchors or enzymes)

Nucleus

Control center holding DNA

Mitochondrion

Energy powerhouse that breaks down nutrients to build ATP.

Rough ER

Studded with ribosomes; synthesizes and modifies proteins.

Smooth ER

Lacks ribosomes; synthesizes lipids

Golgi Apparatus

The cell’s shipping center

Sorts, modifies, and packs products from the ER into transport vesicles.

Lysosome

Clean-up sac packed with digestive enzymes

Peroxisome

Sac packed with metabolic enzymes for fat breakdown and chemical detoxification

Microvilli

Non-moving folds that maximize surface area for absorption

Cilia

Hair-like projections that beat in unison to sweep mucus across the apical surface.

Prophase

First stage of mitosis. Chromatin condenses into visible X-shaped chromosomes, the nuclear envelope breaks apart, and centrosomes migrate to opposite poles

Metaphase

Second stage of mitosis. Sister chromatids line up perfectly down a linear plane in the middle of the cell (metaphase plate).

Anaphase

Third stage mitosis. Centromeres split, and sister chromatid’s part ways as individual chromosomes being pulled to opposite ends of the cell.

Telophase

Final stage of mitosis. Nuclear envelopes reform around the genetic material, chromosomes uncoil back into loose chromatin, and nucleoli reappear.

Cytokinesis

The physical splitting of the cell body.

A microfilament contractile band cinches a cleavage furrow around the cell midline to pinch it into two distinct cells.