Week4

Plasma membrane

Selectively permeable outer boundary that regulates substances entering and leaving the cell.

Diffusion

Movement of solute molecules from an area of higher concentration to lower concentration.

Osmosis

Diffusion of water across a differentially permeable membrane toward higher solute concentration.

Isotonic solution

Equal solute concentrations inside and outside the cell; results in no net water movement.

Hypotonic solution

Lower outside solute concentration relative to the cell; causes water to enter the cell.

Hypertonic solution

Higher outside solute concentration relative to the cell; causes water to exit the cell.

Turgor pressure

Outward pressure in plant cells created by central vacuole water, maintaining plant structure.

Plasmolysis

Deflation of plant cell cytoplasm and central vacuole due to water loss in hypertonic solutions.

Unified Cell Theory

All living things are composed of cells, the cell is life's basic unit, and cells arise from existing cells.

Prokaryotes vs. Eukaryotes

Prokaryotes lack membrane-bound organelles; eukaryotes possess a true nucleus and membrane-bound organelles.

Four universal cell components

Plasma membrane, cytoplasm, DNA, and ribosomes.

Fluid Mosaic Model

Plasma membrane structure featuring a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates.

Active vs. Passive transport

Active transport requires energy to move substances against gradients; passive transport requires no energy.

Mitochondria

Organelles acting as cell powerhouses, producing ATP through cellular respiration.

Chloroplast

Plant organelle containing chlorophyll that carries out photosynthesis.

Lysosomes

Organelles containing digestive enzymes to break down macromolecules and destroy pathogens.

Rough vs. Smooth Endoplasmic Reticulum

Rough ER folds proteins; smooth ER synthesizes lipids and detoxifies substances.

Golgi apparatus

Organelle that sorts, tags, and packages lipids and proteins for distribution.

Endosymbiotic Theory

Theory that mitochondria and chloroplasts originated from free-living prokaryotes incorporated into eukaryotic cells.

Autotrophs vs. Heterotrophs

Autotrophs synthesize their own food; heterotrophs consume other organisms for carbon-based food.

Four steps of food processing

Ingestion, digestion, absorption, and elimination.

Peristalsis

Unidirectional wave-like smooth-muscle contractions moving food through the alimentary canal.

Small intestine function

Primary site of chemical digestion and nutrient absorption, maximized by villi.

Liver functions

Processes blood from intestines, stores glucose as glycogen, produces bile, and detoxifies substances.

Large intestine function

Reabsorbs water from the alimentary canal and compacts undigested waste into feces.