Proteins/Enzymes/Protein Synthesis

protein folding (structure)

allows a protein to have a specific function

what happens if a protein is unfolded?

the ability to do its specific function is lost

functions of a protein

- forms channels for transporting molecules

- catalyzes reactions as enzymes

- protects against diseases as antibodies

- provides structure

what are the monomers of a protein?

amino acids

peptide bonds

bonds that hold amino acids together in a long chain

what part of an amino acids contains NH2

amino group

what part of an amino acids contains COOH

carboxyl group

what part of an amino acids is the side chain

R group

what is special about the R group of an amino acid

it differentiates each amino acid from one another (the unique part of an amino acid)

where are hydrophobic R groups found?

the inner parts of a folded protein

denature/denaturing

unfolding (disruption) of the 3d shape of a protein

when is a protein denatured?

when exposed to extreme temperatures or pH

what does a protein require?

- specific pH

- specific temperature

- chaperonin to help them fold correctly

primary structure of a protein

sequence of amino acids

secondary structure of a protein

alpha helix or beta pleated sheet

tertiary structure of a protein

- folding of the helix or pleated sheet

- overall 3d shape often determined by the R group

quaternary structure of a protein

stacking of multiple polypeptides

catalyst

substance that alters the rate of a chemical reaction without itself being changed or used up

enzymes

proteins that are catalysts in cells

functions of enzymes

- speed up a reaction by lowering activation energy

- allows reactions to take place at lower temperatures

- regulates metabolism

what is being compared in an activation energy graph

a chemical reaction with an enzyme and a chemical reaction without an enzyme

what happens to the activation energy with an enzyme?

the activation energy is lowered

what happens to the reaction with an enzyme?

it is done faster

substrate

the substance affected by an enzyme

active site

region on an enzyme that can bind with a specific substrate

lock-and-key

active site on enzyme fits substrate exactly

induced fit

enzyme and substrate connect and then bend into one another to tighten their connection

true or false: an enzyme can be reused after a reaction is over

true

true or false: an enzyme can help in both a dehydration synthesis reaction and a hydrolysis reaction

true

ways in which an enzyme catalyzes chemical reactions

- holding 2 substances in positions in which they can react with each other

- twisting a substrate molecule slightly so that a chemical bond is weakened and broken

where is DNA (deoxyribonucleic acid) found?

the nucleus (in eukaryotes)

what is the sugar in DNA?

deoxyribose

what is the sugar in RNA (ribonucleic acid)?

ribose

bases in DNA

adenine, thymine, cytosine, guanine - ATCG

bases in RNA

adenine, uracil, cytosine, guanine - AUCG

what is the shape of DNA?

double-helix, it is double stranded

what is the shape of RNA?

single stranded

what comes first? transcription or translation

transcription (c comes before l)

where does transcription take place?

the nucleus

RNA polymerase

connects complementary RNA bases to the DNA template strand, making mRNA

mRNA

messenger RNA, travels to the ribosome, directs tRNA

tRNA

transfer RNA, reads the bases of mRNA in sets of 3, holds complementary anti-codon

what are the sets of 3 bases on mRNA that tRNA reads known as

codons - codes for specific amino acids and/or stop/start signals

mRNA AUG

methionine, typically the start codon of an amino acid

true or false: more than 1 codon can code for the same amino acid

true

where does protein synthesis take place?

ribosomes

what is the result of translation?

proteins (made of 1 or more polypeptide chains)

stop codons

signals protein building is finished

- UAA

- UAG

- UGA

start codons

signals the beginning of protein building

what directs protein synthesis?

DNA