Biochemistry (proteins/enzymes) - Irene Gold Booklet :)

What is the characteristic bond of all proteins

Peptide bond

Describe the primary protein structure

linear sequence of amino acids

Describe the secondary protein structure

Folding of the chain into an Alpha-helix or a Beta-pleated sheet.

What type of bond holds togetehr secondary protein structure

Hydrogen bond

Describe the tertiary structure of a protein

The over all 3D shape and structure of proteins

What type of bond holds together tertiary protein structure

Disulfide bond

Myoglobin is an example of what level of protein structure

Tertiary

Describe the quaternary structure of a protein

association of two or more polypeptides chains to make functional protein

Hemoglobin is an example of what level of protein structure

quaternary

What are Catalysts that speed up rate of reaction by lowering activation energy

Enzymes

What are catelcholamines

Amine hormones made by adrenal medulla (ex. Epinephrine)

What kind of bonds connect the light and heavy chains of an antibody

Disulfide bonds

What releases insulin

Beta cells of pancreas

What are the different types of proteins

Enzymes, catelcholamines, antibodies, peptide hormones

Insulin ________ glycolysis (inhibits or stimulates)

Stimulates

Insulin ________ gluconeogenesis (inhibits or stimulates)

Inhibits

T/F enzymes are not consumed in a reaction

True

What 3 factors affect reaction velocity of an enzyme

Substrate concentration, temperature, pH

The molecule that an enzyme acts upon is known as its

Substrate

What acts as the rate limiting step for an entire metabolic pathway

Allosteric enzymes

PFK is allosterically inhibited by

Increase in ATP

What are isoenzymes

Enzymes that differ in their amino acid sequence and structure but catalyze the same reaction

What is the measure of the affinity an enzyme has to its substrate

Km

Decreased Km = ________ affinity

Increased

When an enzyme is saturated the maximum rate it will be catalyzed is called

Vmax

Km = _____ Vmax

1/2

What is Vmax

The point when all active sites are bound to substrate

How does competitive inhibition affect Km and Vmax

Increase Km, no change in Vmax

How does non-competitive inhibition affect Km and Vmax?

No change in Km, decreased Vmax

What is Gibbs free energy

Amount of energy available to determine if a reaction can occur

If delta G is 0 what is the energy state

Equilibrium

if delta G is positive what is the energy state

Reaction is non-spontaneous and unfavorable (endergonic)

If delta G is negative what is the energy state

Reaction is spontaneous and favorable (exergenic)

An exergonic reaction will ______ energy (release or absorb)

Release

An endergonic reaction will ______ energy (release or absorb)

Absorb

What is a steroid

A hydrophobic lipid molecule that is insoluble in water

What is the most abundant steroid in humans

Cholesterol

What is the rate limiting step of cholesterol synthesis?

HMG-CoA reductase

What is the rate limiting step in steroid synthesis

Desmolase

Describe the cycle of bile salts

Made in liver, secreted into bile, stored in gall bladder, reabsorbed into the blood once in the small intesetine

What are lipoproteins

Particles of protein and fat that carry fats and cholesterol thru the blood once

What is the least dense type of lipoprotein

Chylomicrons

Function of chylomicrons

Transport triglycerides to peripheral tissues and cholesterol to the liver

Function of VLDL

Transport triglycerides from liver to peripheral tissues

What are LDLs derived from

VLDLs

What type of lipoprotein carries the most cholesterol

LDL

High plasma levels of LDL will increase the risk of

Heart disease (bad cholesterol)

Function of LDL

Transports cholesterol from liver to peripheral tissue

What is considered "good cholesterol"

High density lipoprotein (HDL)

Function of HDL

Transport cholesterol from peripheral tissues back to liver

Two naturally occurring types of nucleic acids

Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)

What are the nucleotides that make up nucleic acids

Phosphate + pentose sugar + nitrogenous base

What are the nucleosides

pentose sugar + nitrogenous base (no phosphate)

What are the PURINE nitrogenous bases

Adenine and Guanine

What are the PYRIMIDINE nitrogenous bases

cytosine, thymine (DNA only), uracil (RNA only)

Adenenine bases will pair with

Thymine (or uracil in RNA)

Cytosine bases will pair with

Guanine

What type of bond holds together DNA and RNA

Phosphodiester bonds (covalent)

To make DNA a polynucleotide chain will be joined together by a phosphate group at position ________ in the pentose sugar and a hydroxyl group at position _______ in the next pentose sugar

5;3

T/F hydrogen bonds are only found in RNA not DNA

False - in DNA not RNA

What is the rate limiting enzyme for purine metabolism

Xanthine oxidase

What will purines be broken down into

Uric acid

The formation of deoxyribose from ribose is what type of reaction

Reduction (gaining electron)

Where does DNA replication occur

Nucleus

What cell cycle phase will DNA replication occur in

S phase

DNA replication occurs in what direction

5' to 3'

What enzyme is used for DNA replication

DNA polymerase

T/F transcription occurs in the nucleus

True

What enzyme is used for transcription

RNA polymerase

What is DNA transcription

Process of re-writing genetic info from DNA into messenger RNA

What is a codon

group of 3 mRNA bases that codes for a single amino acid

What is always the 1st amino acid coded for

Methionine (AUG)

What are the start codons

AUG and GUG

What are the stop codons

UAA, UAG, UGA

Where does protein synthesis occur

ribosomes

What enzyme is for protein synthesis

Peptidyl transferase

What connects mRNA to the amino acid they encode

Transfer RNA

The stage where the finished polypeptide chain is released is called

Termination