Chapter 4,5,6 notes

Phospholipids

Form the bilayer of the plasma membrane; hydrophilic heads face outward, hydrophobic tails face inward.

Cholesterol

Stabilizes membrane fluidity, preventing the membrane from becoming too rigid or permeable.

Glycolipids

Located on the outer surface of the plasma membrane; involved in cell recognition and communication.

Integral Proteins

Span the plasma membrane; act as channels, transporters, or receptors for signaling.

Peripheral Proteins

Loosely attached proteins involved in signaling, enzymatic activity and interactions with the cytoskeleton.

Simple Diffusion

The movement of small, nonpolar molecules (like O2 and CO2) directly through the bilayer without the need for energy.

Facilitated Diffusion

The transport of larger, polar molecules through channel or carrier proteins without energy, following concentration gradients.

Active Transport

The movement of ions or large molecules against their concentration gradient via pumps, requiring ATP.

Endocytosis

The process where the membrane engulfs large particles or liquids to form a vesicle; requires ATP.

Exocytosis

The process in which a vesicle fuses with the membrane to release large molecules; requires ATP.

Osmosis

The movement of water across a selectively permeable membrane from an area of low solute concentration to high solute concentration.

Osmotic Pressure

The pressure exerted by water as it moves through the membrane during osmosis, more solutes lead to higher osmotic pressure.

Tonicity

Describes how a solution's solute concentration compares to that of a cell's interior, influencing osmosis.

Isotonic Solution

A solution with the same solute concentration as the cell, resulting in no net water movement.

Hypotonic Solution

A solution with a lower solute concentration than inside the cell, causing the cell to swell as water enters.

Hypertonic Solution

A solution with a higher solute concentration than inside the cell, causing the cell to shrink as water leaves.

Resting Membrane Potential (RMP)

The electrical charge difference across the cell membrane when the cell is at rest, typically around -70 mV.

Na+/K+ Pump

A pump that actively transports 3 Na+ out of the cell and 2 K+ into the cell, creating concentration gradients.

Human Cell Organelles

Specialized structures within the cell that perform distinct tasks, such as energy production and protein synthesis.

Epithelial Tissue

Closely packed cells forming sheets that protect, absorb, and secrete; found in skin and digestive lining.

Connective Tissue

Characterized by widely spaced cells surrounded by an abundant extracellular matrix; supports and binds other tissues.

Muscle Tissue

Tissue composed of cells capable of contraction for movement; includes skeletal, cardiac, and smooth muscle.

Nervous Tissue

Composed of neurons that transmit impulses and supporting cells (neuroglia); found in the brain, spinal cord, and nerves.

Transcription

The process by which RNA polymerase copies DNA into mRNA in the nucleus.

Translation

The process by which mRNA is used to synthesize proteins at the ribosome.

Cell Cycle

Includes interphase (G1, S, G2) and M phase (Prophase, Metaphase, Anaphase, Telophase) for cell division.

Mitosis

The M phase of the cell cycle where the cell's chromosomes are divided and separated into two daughter cells.

Melanin

A brown/black pigment that determines skin color and provides protection against UV exposure.

Sebaceous Glands

Glands attached to hair follicles that secrete sebum to lubricate the skin and prevent dryness.

Sweat Glands

Glands that help regulate body temperature and remove waste through sweating.

Nail Structure

Keratinized plates that protect fingertips and aid in fine touch.

Hair Structure

Composed of a keratin shaft, root, follicle, and bulb, serving to protect and regulate temperature.