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The solvent in which all chemical reactions in living cells take place. 80% of a cell's mass is this
h20, water
the attractive interaction of a hydrogen atom with an electronegative atom, such as nitrogen, oxygen or fluorine
Hydrogen Bond
The structure formed when 2 or more polypeptide chains bind together
The quaternary structure
A protein that has lost most of its secondary tertiary and quaternary structure is...
This is very often reversible
Denatured/ Denature
The five forces that create the tertiary structure of a protein
1-covalent disulfide bonds between cysteine amino acids
2-Ionic interactions mostly between acid and base side chains
3-hydrogen bonds
4-Van der Waals forces
5_ hydrophobic side chains pushed away from H20
The three dimensional shape formed when the peptide chain curls and folds
Tertiary structure
These are the two shapes formed by the secondary structure of polypeptides
These are formed by hydrogen bonds
Alpha helix
Beta pleated sheets
The number and sequence of amino acids in a polypeptide/ protein
Primary structure
-A chemical reaction between a carboxyl group of one molecule and the amine group of another molecule.
-releases molecules of H2O
Peptide Bond
-These amino acids cannot be produced by the human body and must be ingested directly
-There are 10 of these
Essential amino acids
-Chains of amino acids linked together by peptide bonds
-also called polypeptides
- An organinc compound that contains 4 rings
-includes cholesterol
- A chemical compound posessing both hydrophilic and lipophilic properites.
-Molecules especially suited for components of membranes
Ampiphile/ Ampiphatic
-Built on a glycerol backbone
-has two fatty acids and a phosphate group opposite from the fatty acids making it polar
-Also called fat cells, are specialized cells whose cytoplasm contains almost nothing but triglycerides
- the three carbon backbone usually attached to three fatty acids
Constructed with a 3 carbon backbone called Glycerol which is attached to 3 fatty acids
These fatty acids contain one or more double c=c bonds
Unsaturated Fatty Acids
This fatty acid contains only single c-c double bonds
Saturated Fatty Acids
-long chains of carbons truncated with a carboxylic acid at one end.
-can be sturated or unsaturated
Fatty Acids
Any biological molecule that has low soulbility in H2O and highly soluble in non-polar organic solvents
- A chemical reaction that involves the loss of h2o from the reacting molecule
-a subset of elimination reactions
-A chemical reaciton in which H2O molecules are split into H+ atoms and HO- molecules
-Sometimes called dissolution
- is the process of attraction and association of molecules of a solvent with molecules or ions of a solute
A water soluble molecule that can transiently bond with H2O
Hydrophilic molecule
A non-polar molecule that is repelled from a mass of water
Hydrophobic molecule
-Also called sugars or saccharides
-are made from only carbon and water
THe most commonly occuring 6 carbon carbohydrate
-accounts for 80% of the carbohydrates absorbed by humans
Formed by the liver by a transformation from glucose
The three components of a nucleotide are:
1: a five carbon sugar
2-a nitrogenous base
3-a phosphate group
Nucleotides are joined by ___ betwen the phospate group of one nucleotide and the 3* carbon of the pentose forming DNA. In this convention the DNA is written from the ___ end to the ___ end
-Phosphodiester bond

Globular proteins that function as a catalyst in cellular reactions.
-these lower energy of activiation increasing the reaction rate
Enzymes do not alter the ___ of a reaction
What the enzyme works on is called the
The area where the enzyme bonds, usually with noncovalent bonds, is called the ___
Active site
When an enzyme binds to a substrate the entire unit is called the
Enzyme-substrate complex
As the relative concentration of a substrate incereases, the rate of the reaction also increases, but to a lesser and lesser degree until a maximum rate (Vmax) has been achieved.
Saturation kinetics
Most enzymes need this non-protein component to reach optimal activity
Agents that bind covalently to enzymes and disrupt their function are
Irreversible inhibitors
These compete with the substrate binding of an enzyme by binding reversibly with active sites
reversible/ competitive inhibitors
These noncovalently bind to an enzyme to change its shape so that it cannot bind to the active site of a substrate
nonccompetitive inhibitors
An enzyme that is not activated and is waiting on activation by another enzyme or environmental changes
Zymogen or Proenzyme
The modification of an enzyme by the bonding of a promoter or inhibitor at a specific binding site on an enzyme
-there can be positive and negative feedback involved
Allosteric interaction
When one of the products downstream comes back and inhibits further reaction
-this usually happens when a cell has produced enough reaction product
Negative feedback
When one of the products downstream returns to activate the reaction further
Positive feedback
When the first substrate in an enzymatic reaction changes the shape of the enzyme allowing other substrates to bind more easily
positve cooperativity
When the first substrate changes the shape of the enzyme so that it cannot bind to the other substrates
Negative cooperativity
- includes all cellular reactions
-called anabolism or
Molecular degradation
Catabolism (catastrophy)
Molecular Synthesis
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