Bio 111 Study Guide Chapter 4 - Energy and Membranes

Flashcards on energy, enzymes, and membranes to help review Bio 111 lecture notes.

Energy

The ability to do work.

Kinetic Energy

Energy of motion.

Thermal (heat) energy

Kinetic energy associated with the movement of atoms and molecules; related to temperature.

Light (solar) energy

Electromagnetic radiation visible to the human eye; contains photons.

Potential Energy

Stored energy available to do work, such as in a compressed spring or concentration gradients.

Chemical Energy

Potential energy stored in chemical bonds.

Thermodynamics

The study of energy transformations.

1st Law of Thermodynamics

Energy cannot be created or destroyed, only converted from one form to another.

2nd Law of Thermodynamics

Every energy transfer or transformation increases the entropy (disorder) of the universe; some energy is lost as heat.

Metabolism

The totality of an organism's chemical reactions.

Anabolism (Anabolic)

Metabolic pathways that construct complex molecules from simpler ones; requires energy.

Catabolism (Catabolic)

Metabolic pathways that break down complex molecules into simpler ones; releases energy.

Endergonic

A chemical reaction that requires a net input of energy.

Exergonic

A chemical reaction that releases energy.

Oxidation

The loss of one or more electrons from a substance involved in a chemical reaction.

Reduction

The gain of one or more electrons by a substance involved in a chemical reaction.

Photosynthesis

Plants convert light energy into chemical energy, stored in sugars.

Cellular Respiration

Converting chemical energy stored in glucose into a usable form of energy for cells, primarily ATP.

Hydrolysis

Breaking bonds with the addition of water, releasing energy.

Dehydration Synthesis

Removing water molecules to form new bonds.

ATP

Adenosine triphosphate; the energy currency of the cell; main energy carrier in cells.

Chemical components of ATP

A nitrogenous base (adenine), a ribose sugar, and three phosphate groups.

Enzyme

An organic molecule that catalyzes a chemical reaction without being consumed.

Catalyst

A substance that speeds up a chemical reaction without being consumed.

Activation Energy

The energy needed to initiate a reaction.

Active Site

The specific region of an enzyme where substrate binds.

Substrate

The reactant on which an enzyme works; binds to the active site where the reaction takes place.

Cofactors and Coenzymes

Inorganic or organic substances required for enzyme activity.

Inhibitors

Substances that decrease the activity of an enzyme; can be competitive or noncompetitive.

Activators

Molecules that improve or change the activity of an enzyme.

Denature

When a protein loses its natural shape and function.

Metabolic Pathway

A series of chemical reactions, each facilitated by a specific enzyme, to convert an initial substrate to a final product.

Negative Feedback

Accumulation of the reactions product causes the reaction to slow down.

Positive Feedback

Accumulation of the reaction's product causes the reaction to speed up.

Transport Proteins

Proteins embedded in the membrane that assist in the movement of substances across the membrane.

Passive Transport

Movement of molecules across the membrane without the use of energy; includes diffusion.

Active Transport

Movement of molecules across the membrane requiring energy (ATP).

Simple Diffusion

Diffusion across a membrane without the assistance of transport proteins.

Facilitated Diffusion

Diffusion across a membrane with the assistance of transport proteins.

Down/With (concentration gradient)

Movement from an area of high concentration to low concentration.

Up/Against (concentration gradient)

Movement from an area of low concentration to high concentration; requires energy.

Diffusion

The net movement of particles from an area of higher concentration to an area of lower concentration.

Osmosis

The diffusion of water molecules across a selectively permeable membrane.

Hypertonic

A solution with a higher solute concentration outside the cell, causing water to move out and the cell to shrink.

Hypotonic

A solution with a lower solute concentration outside the cell, causing water to move in and the cell to swell.

Isotonic

A solution with equal solute concentrations inside and outside the cell; water moves in and out at the same rate.

Turgor Pressure

Plant structural support and rigidity; stores water which causes the cell to swell and push against the cell wall.

Proton Pump

A specialized protein that transports ions across the membrane, creating an electrochemical gradient.

Endocytosis

A process that moves bulk material into a cell.

Exocytosis

A process that moves bulk material out of a cell.