Molecular and Cellular Biology

Compound

molecule made up of at least two different atoms

Which is stronger: ionic or covalent bonds?

Ionic bonds are generally stronger than covalent bonds due to the electrostatic attraction between oppositely charged ions.

Atom that donates an electron and becomes positively charged

Cation

Atom that gains an electron and becomes negatively charged

Anion

Cohesion

Attraction between two water molecules

Cohesion creates…

Surface tension in liquids.

Dehydration synthesis

when one subunit loses a hydroxyl group and the other loses an atom of hydrogen

First law of thermodynamics

energy cannot be created nor destroyed

Second law of thermodynamics

Energy flows within a system until it reaches equilibrium. It states that the total entropy of an isolated system can never decrease over time.

Anabolism

use energy to build complex molecules from simpler molecules

Catabolism

Release energy through the breaking of bonds

Oxidizing agent

Easily reduced, gains an electron Ex. Fe+3

Reducing agent

Donates an electron. Ex. H

Subtrate

molecule that an enzyme reacts with

Enzyme specificity

The tendency of an enzyme to bind to a certain substrate and catalyze a certain set of rxns

Coenzyme

A nonprotein molecule that binds to an enzyme and helps the enzyme do its job

Active site

grooves on the enzyme surface that binds to the substrate(s) of a chemical rxn

Induced fit

Active site of some enzymes changes shape when bound to a substrate

Example of an induced-fit model

hand-in-a-glove

Two environmental factors that influence enzyme activities

pH and temperature

Catalysts

lower the activation energy of a chemical rxnIn

Competitive Inhabition

When a molecule of a similar shape to the substrate of an enzyme competes with the substrate for the active site of an enzyme

Cooperative Binding

A substrate bound to one active site effects a change in the other active sites to either increase the affinity of those sites for the substrates or decrease

The Calvin cycle produces one molecule of glucose from what three molecules?

ATP, NADPH, CO2