Honors Biology – Complete Study Guide

Prokaryotic Cells

Cells that have no nucleus or membrane-bound organelles, example: bacteria.

Eukaryotic Cells

Cells that have a nucleus and membrane-bound organelles, examples: plants and animals.

Plant Cells

Cells that have a cell wall, chloroplasts for photosynthesis, and a large central vacuole.

Animal Cells

Cells that do not have a cell wall or chloroplasts, usually have smaller vacuoles and lysosomes.

Nucleus

Organelle that controls cell activities and stores DNA.

Cell Membrane

Controls what enters and leaves the cell and is composed of a phospholipid bilayer.

Mitochondria

Organelles that produce ATP energy for the cell.

Ribosomes

Organelles that are responsible for making proteins.

Diffusion

Movement of molecules from high to low concentration.

Osmosis

The diffusion of water across a selectively permeable membrane.

Facilitated Diffusion

Movement of substances from high to low concentration through membrane proteins.

Active Transport

Movement of substances against their concentration gradient, requiring ATP energy.

Sodium-Potassium Pump

Active transport mechanism that moves 3 sodium ions (Na⁺) out of the cell and 2 potassium ions (K⁺) into the cell.

Hypertonic Solution

A solution with a higher concentration of solute outside the cell than inside, causing water to move out.

Hypotonic Solution

A solution with a lower concentration of solute outside the cell than inside, causing water to move in.

Isotonic Solution

A solution with equal solute concentration inside and outside the cell, balancing water movement.

Photosynthesis

Process occurring in chloroplasts that uses sunlight, water, and carbon dioxide to produce glucose and oxygen.

Cellular Respiration

Process primarily occurring in mitochondria that breaks down glucose to make ATP.

Homeostasis

The maintenance of stable internal conditions in an organism despite changes in the external environment.

Endosymbiotic Theory

Theory that explains the origins of mitochondria and chloroplasts as former independent bacteria.

Negative Feedback

A process that reverses changes to maintain homeostasis, such as regulating body temperature.

Gas Exchange

Process occurring in alveoli where oxygen is absorbed into the blood and carbon dioxide is released.