Enzymes and their function WK 1

Question 1

Define enzymes and substrates

Answer 1

enzymes: proteins that function as biological catalysts
-permit reaction to occur rapidly at body temp
-lower activation energy

substrate: substance enzyme acts upon

Question 2

Describe an enzymes structure and what effects it’s function

Answer 2

not consumed by reactions
-one can consume millions of substrate molecules per min
-temp, pH and other can change shape/function;
-change ability to bind to substrate -enzymes vary optimum pH

Question 3

Describe enzyme action with images

Answer 3

-substrate approaches enzymes active site
-molecules bind together forming enzyme-substrate complex
- (substrate specificity=lock and key complex)
-enzyme releases reaction products
-enzyme unchanged and can repeat process

Question 4

Define co factors and how they function

Answer 4

essential to function
-some bind to enzyme and induce change in shape which activates active site
-some inorganic

Question 5

Define coenzymes and their function

Answer 5

organic cofactors derived from water-soluble vitamins
-accept electrons from enzyme in one metabolic pathway and transfer them to diff enzyme in other e.g. NAD+

Question 6

Describe metabolic pathways and their regulation

Answer 6

chain of reactions, with each step usually catalysed by different enzyme
-A–>B–>C–>D (between arrows are alpha, beta, omega)
-A is intial reactant, B and C=intermediates, D is end product

regulation: cells can turn on/off when end product are needed/ not needed

Question 7

Describe the structure of nucleotides

Answer 7

-sugar (monosaccharides)
-one or more phosphate groups
-nitrogenous base (single/double carbon-nitrogen ring)

Question 8

Describe the structure of ATP

Answer 8

adenine (nitrogenous base)
ribose (sugar)
phosphate groups (3)

Question 9

What is the function of guanosine triphosphate

Answer 9

involved in energy transfer

Question 10

Describe function of cyclic adenosine monophosphate

Answer 10

formed by removal of 2nd/3rd phosphate groups from ATP
-triggered by hormone binding to cell surface
-becomes secondary messenger within cell

Question 11

Define nucleic acids. Describe difference between RNA and DNA

Answer 11

polymer of nucleotides
DNA:
-contains millions of nucleotides
-constitutes genes (instructions for synthesising proteins)
RNA:
-messenger, ribosomal, transfer
-carries out genetic instruction for synthesising proteins