AP Biology Unit 2

The role of membrane-bound organelles in metabolic function of cells.

Compartmentalization

Theory of Endosymbiosis

Explains the evolution of mitochondria and chloroplasts through symbiotic relationships.

Osmosis

The process of movement of water across a selectively permeable membrane based on osmotic gradients.

Surface area to volume ratio

Influences the efficiency of cells in terms of nutrient uptake and waste elimination.

Water potential

A measure that combines the effects of solute concentration and pressure potential, important for understanding plasmolysis and turgidity.

Plasmolysis

The process in which cells lose water in a hypertonic solution, causing the cell membrane to pull away from the cell wall.

Turgidity

The state of being swollen or firm due to water uptake, important for plant cell structure.

Phospholipids

Lipids that make up the cell membrane, consisting of hydrophilic heads and hydrophobic tails.

Cholesterol

A component of cell membranes that helps to maintain fluidity and stability.

Transport proteins

Proteins that assist in the movement of substances across a cell membrane.

Facilitated diffusion

The process by which molecules move across a membrane via transport proteins down their concentration gradient.

Active transport

The movement of molecules against a concentration gradient, requiring energy, usually in the form of ATP.

Na+/K+ pump

A membrane protein that pumps sodium ions out of the cell and potassium ions into the cell, creating an electrochemical gradient.

Cotransporters

Proteins that help transport secondary molecules against their concentration gradient by coupling their movement with that of another molecule.

Endocytosis

The process through which large materials enter a cell by engulfing them in a membrane.

Exocytosis

The process through which materials are expelled from a cell by the fusion of vesicles with the plasma membrane.

Ribosomes

Non-membrane subcellular structures that synthesize proteins according to messenger RNA sequences.

Endomembrane System

A group of membrane-bound organelles and components that work together to modify, package, and transport materials within the cell.

Golgi Complex

A membrane-bound structure with flattened sacs that modifies and packages proteins and other molecules.

Endoplasmic Reticulum (ER)

An organelle providing mechanical support, maintaining cell shape, and facilitating protein and lipid synthesis.

Mitochondria

Double-membraned organelles involved in aerobic cellular respiration, generating ATP for energy.

Lysosomes

Membrane-enclosed sacs containing hydrolytic enzymes for digestion and programmed cell death.

Vacuoles

Membrane-bound sacs that have various functions, including storing materials and maintaining turgor pressure in plants.

Chloroplasts

Double-membraned organelles found in plants and photosynthetic algae that are the site of photosynthesis.

Surface Area-to-Volume Ratio

A measure that affects the efficiency of nutrient absorption, waste elimination, and thermal energy exchange in cells.

Facilitated Diffusion

The process that requires transport proteins to aid charged ions and large polar molecules in crossing the plasma membrane.

Selective Permeability

The capacity of biological membranes to allow certain substances to pass while restricting others.

Osmoregulation

The process that maintains water balance and controls internal solute composition within an organism.

Active Transport

The movement of molecules across membranes requiring energy input to transport substances against their concentration gradient.

Endocytosis

A process where a cell takes in large molecules by folding the plasma membrane into vesicles.

Exocytosis

A process where internal vesicles fuse with the plasma membrane to release materials outside the cell.

Hydrophobic Interior

The non-polar region of a membrane that prevents the passage of ions and polar molecules.

Internal Membranes

Membranes that compartmentalize metabolic processes and enhance the efficiency of cellular functions.

Prokaryotic Cells

Cells that typically lack membrane-bound organelles and possess specialized internal structures.

Eukaryotic Cells

Cells that contain membrane-bound organelles, including mitochondria and chloroplasts, which compartmentalize cellular functions.

What are ribosomes made of?

Ribosomes are made of ribosomal RNA (rRNA) and proteins, forming a complex that synthesizes proteins in the cell.

According to what sequence do ribosomes synthesize proteins

the sequence of amino acids dictated by messenger RNA (mRNA)

Substrate-level phosphorylation

A metabolic reaction that produces ATP by directly transferring a phosphate group from a phosphorylated substrate to ADP.