Plasma Membrane, Cellular Transport, Energy, and Enzymes

Fluid Mosaic Model

Membrane structure consisting of a flexible phospholipid bilayer with proteins embedded in it.

Membrane Proteins

Proteins that serve various functions including transport, reception, recognition, enzymatic activity, and adhesion.

Passive Transport

Movement of molecules across a membrane without the use of energy, from high to low concentration.

Diffusion

Process by which molecules spread out from a region of high concentration to a region of lower concentration.

Osmosis

The movement of water toward a higher concentration of solute.

Hypotonic

A solution that causes a cell to swell due to water entering the cell.

Isotonic

A balanced solution where the concentration of solute is equal inside and outside the cell.

Hypertonic

A solution that causes a cell to shrink due to water leaving the cell.

Osmoregulation

The process by which organisms maintain the balance of water and solutes.

Tonicity Effects

Impact of solution concentration on cell shape; plants become turgid in hypotonic solutions and animals may burst.

Kinetic Energy

Energy of motion.

Potential Energy

Stored energy.

First Law of Thermodynamics

States that energy cannot be created or destroyed, only transformed.

Second Law of Thermodynamics

States that energy transformations increase the entropy (disorder) of a system.

Entropy

A measure of disorder in a system.

Endergonic Reaction

A reaction that absorbs energy.

Exergonic Reaction

A reaction that releases energy.

Phosphorylation

The addition of a phosphate group, often from ATP, to energize a molecule.

Enzymes

Biological catalysts that lower activation energy to speed up reactions.

Substrate

The reactant in a biochemical reaction.

Active Site

The region of an enzyme where the substrate binds.

Competitive Inhibition

A type of inhibition where a competitor blocks the active site of an enzyme.

Noncompetitive Inhibition

A type of inhibition where an inhibitor changes the shape of the enzyme.

Enzyme Conditions

Factors such as pH, temperature, and salt concentration that affect enzyme activity.

ATP Functions

ATP powers transport processes, movement, and chemical synthesis in cells.

Electromagnetic Spectrum

The range of all light wavelengths; visible light includes ROYGBIV.

Visible Light

Light made of different wavelengths; shorter wavelengths carry more energy.

Pigments

Molecules that absorb specific wavelengths of light; chlorophyll is an example.

Light-dependent Reactions

Photosynthesis reactions that make ATP and NADPH.

Calvin Cycle

The set of chemical reactions in photosynthesis that convert CO2 into glucose using ATP and NADPH.

Photosystems

Clusters of pigments in thylakoid membranes that capture light.

Oxidation

The process of losing electrons; in photosynthesis, H2O is oxidized.

Reduction

The process of gaining electrons; in photosynthesis, CO2 is reduced.

Light Reactions

Reactions that occur in thylakoids, generating ATP and NADPH.

ATP/NADPH Function

These molecules are used in the Calvin Cycle to build glucose.

Leaf Structure

Chloroplasts are located in mesophyll cells; stomata facilitate gas exchange.

Autotrophs

Organisms that produce their own food; include plants.

Heterotrophs

Organisms that consume other organisms for food.

Cellular Respiration Equation

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP.

Oxidation in Respiration

Losing electrons during metabolic reactions.

NAD+ / NADH

An electron carrier; NAD+ becomes NADH upon gaining electrons.

Electron Transport Chain (ETC)

A series of proteins in the inner mitochondrial membrane that produces ATP.

Chemiosmosis

Process where H+ gradient drives ATP synthesis.

ATP Synthase

The enzyme that converts ADP and inorganic phosphate (P) into ATP.

Glycolysis

The first step of cellular respiration occurring in the cytoplasm, converting glucose to 2 pyruvate and producing 2 ATP and 2 NADH.

Krebs Cycle

Also known as the Citric Acid Cycle, it occurs in the mitochondria and produces CO2, NADH, FADH2, and ATP.

Oxidative Phosphorylation

The process that produces the majority of ATP during cellular respiration.

H+ Gradient

A concentration gradient of hydrogen ions established in the inner membrane that drives ATP production.

ATP Yield

The net production of 36-38 ATP from one glucose molecule during cellular respiration.

Anaerobic Respiration

Respiration without oxygen, resulting in less ATP production and leading to either lactic acid or alcohol fermentation.

NAD+ Regeneration

The process of regenerating NAD+ during fermentation to allow glycolysis to continue.

Key Enzymes in Cellular Respiration

ATP synthase and phosphofructokinase, important for ATP production.