Biochemistry test #1

What is biochemistry?

What is the basis of life where biochemical reactions are involved in such areas as breaking down food molecules?

What is a protein?

What are polymers of amino acids?

What are the two major types of proteins?

fibrous and globular

What are amino acids?

What contains a amino group (-NH2),a carboxyl group (COOH), and an R group, all bonded to the central carbon atom. The R group may be a hydrocarbon or they may contain functional group.

What is an alpha amino acid?

which the amino group is bonded to the carbon next to the carboxyl group

What are the major classifications of amino acids?


What are zwitterions?

What are amino acid with a positively charged end and a negatively charged end?

What is the isoelectric point?

What is the pH at which a sample of an amino acid has

How do amino acids combine to form proteins?

Amino acids combine by dehydration synthesis to form proteins

What is a dipeptide?

What is it called when two amino acids are combined?

What is a tripeptide?

What is it called when three amino acids are combined?

What do we mean by the C-terminal end and the N-terminal end of a protein?

C terminal end- carboxyl end
N terminal end- amino end

What is a polypeptide?

What is it called when many amino acids are combined?

What is the primary structure of a protein?

is the sequence of amino acids connected by peptide bonds

What is the secondary structure of a protein?

The shape the amino acid takes on. The arrangement of polypeptide backbone of the protein in space. Two kinds of repeating pattern known as a-helix and B-sheet.

What is the tertiary structure of a protein?

overall 3D shape of the protein that results from the folding of a protein chain. Depends mainly on attractions of amino acid side chains that are far apart along the same back bone.

What is the quaternary structure of a protein?

The way in which two or more polypeptide sub-units associate to form a single three-dimensional protein unit. Non-covalent.




is a conjugated quaternary protein composed of four polypeptide chains

How are proteins denatured?

involves the disruption and destruction of both the secondary and tertiary structures. Not strong enough to break peptide bonds-primary structure remains the same

What are examples of denaturation?


What are stereoisomers?

isomers which have a different arrangement of their atoms in space

What are the two groups for stereoisomers?

enantiomers and diastereomers

What is a mirror image?

images that are laterally reversed

What are enantiomers?


What are diastereomers?

molecules that are not mirror images and not superimposable

What do we mean by chiral molecules?


What is the most common cause of chirality in organic molecules?

four different groups are attached to a carbon atom

What is a stereo center?

chiral carbon

What are enzymes?

a protein or other molecule that acts as a catalyst for a biological reaction

What are riboenzymes?

RNA molecules that are capable of catalyzing specific biochemical reactions

What are two respects which make enzymes remarkable?

1. enzymes are specific- they can only catalyze certain reactions
2. used over and over again

What do we exactly mean by the specificity of enzymes?

the limitation of the activity of an enzyme to a specific substrate, specific reaction or specific type of reaction


a nonprotein part of an enzyme that is essential to the enzyme's catalytic activity; a metal ion or a coenzyme


an organic molecule that acts as an enzyme cofactor


a reactant in an enzyme-catalyzed reaction

active site

a pocket in an enzyme w/ the specific shape and chemical makeup necessary to bind a substrate

Enzyme-substrate concentration

under most conditions the rate of an enzyme catalyzed reaction is controlled by the amount of substrate and the overall efficiency of the enzyme


enzyme activity increases with increasing temp up to the body temp. Higher than that- enzymes begin to denature


optimum pH for stomach- pepsine 4'0
-other body reactions- pH 7

What is the enzyme-substrate complex?

Intermediate state where the enzyme and substrate are trying to fit into one another

What is the Lock and Key Model of Enzyme action?

the substrate is described as fitting into the active site as a key fits into a lock

What is the Induced-Fit model?