Bio exam 1 info

Question 1

Activation energy

Answer 1

Energy to get started, even thermodynamic favored chemical reactions require Ea

Question 2

Enzymes characteristics

Answer 2

Enzymes lower activation energy in almost all chemical reactions in cells, the enzyme is not altered by the reaction, the enzyme does not cause reaction to occur, but it does increase the rate of reaction, enzymes increase free energy (in transition state), enzymes are proteins that act as catalysts for biological reactions

Question 3

Ribozymes

Answer 3

All enzymes are proteins, but there are catalytic RNA molecules

Question 4

Ligand

Answer 4

Molecule or ion that binds to another molecule (protein), this binding is very specific and can involve several weak bonds, causes protein to change shape, overall strong interaction

Question 5

Cofactors

Answer 5

Nonprotein molecules or inorganic ions, often metal ions, that some proteins require in order to function, includes coenzymes and ATP

Question 6

Binding affinity:

Answer 6

Strength of interaction

Question 7

R group modification

Answer 7

Addition of a chemical group to an amino acid changes its interaction with nearby amino acids and the protein changes shape

Question 8

Proteolysis

Answer 8

Some long proteins mush be shortened by breaking a peptide bond by hydrolysis and protein can be synthesized but not activated until appropriate time and location, it has an extra piece of itself- needs to me removed as it blocks the active site

Question 9

Enzymes are slightly specific for their substrates (the reactants)

Answer 9

Substrate molecules bind to the “active site” of the enzyme
Enzymes have a 3D shape that determines the specificity(lock and key fit)

Question 10

How enzymes work

Answer 10

Two different substrates enter into the active site on the enzyme(this is the very specific fit for the substrates and enzyme, once it goes through enzyme-substrate complex, the enzyme releases one product

Question 11

Endergonic reactions can be driven by

Answer 11

Coupling to Exergonic reactions
An Exergonic reaction will release energy at ATP hydrolysis, that released energy can be used in Endergonic reaction to form products

Question 12

Enzyme-substrate complex (ES) forms

Answer 12

Held together by hydrogen bonds, electrical attraction, or covalent bonds

Question 13

Induced fit

Answer 13

Enzyme (e) may change when bound to the substrate but returns to its original form

E+S-ES-E+P
Enzyme original form and product released