enzymes

Question 1

define protein

Answer 1

• type of biomacromolecule made of amino acid chains folded into a 3d shape

Question 2

why are proteins important?
why are they functionally diverse?

Answer 2

• crucial to the functioning and development of all living organisms
• carries out essential cellular functions of life
• many roles in structure, function and regulation of the body’s cells, tissues and organs

Question 3

explain the diversity of proteins

Answer 3

arises through the ability to create many combinations of:
- amino acids
- polypeptide chain lengths, shapes, sizes
= folds into different functional structures post translation

Question 4

what would happen to a protein’s functionality if it was incorrectly folded?

Answer 4

• changes to original sequence of amino acids= protein cannot fold correctly
• end up with the wrong shape= cannot carry out its function/specialised role
  –> must be folded inot the correct shape to function

Question 5

define proteome

Answer 5

whole set of proteins produced by an organism or cell

WITHIN EACH CELL
genome = same
proteome= different

Question 6

what are enzymes?

Answer 6

type of protein that speed up (catalyses) chemical reactions inside cells
- lowers the activation energy of reaction

change in substrate conc= ↑or↓ enzyme produced to conserve ATP

Question 7

what are some properties of enzymes?

Answer 7

• specific: active site is complementary shaped to substrate= only binds to specific reactant
• reusable: remain unchanged during reaction= can catalyse future reactions

Question 8

what is the role of enzymes on biochemical pathways?

Answer 8

regulates biochem pathways by interacting with substrate molecules in series of intermediate steps
- form enzyme-substrate complexes
- chemical bonds can be broken down= smaller molecules
- chemical bonds set to create larger complex molecules

influence entire biochem pathways by catalysing each step

Question 9

what is enzyme optimum conditions

Answer 9

enzymes operate most efficiently with their narrow range of set conditions
- activity is greatest= max products produced per unit of time

Question 10

compare the lock and key and the induced fit model

Answer 10

• active site is proper shape to substrate
• active site has somewhat complementary shape to substrate: active site changs to fit when binding to substrate forming substrate complex

Question 11

what is denaturing

Answer 11

• certain conditions disrupt the bonds within enzyme and changes its 3d shape
• active site changes shape= substrate can no longer bind
• enzyme= non-functional

Question 12

what is a coenzyme

Answer 12

non-protein organic molecules that assist enzyme function
- bind to active site to donate energy or molecules= changes structure
(cannot be immediately reused)

Question 13

define cycling of enzyme

Answer 13

coenzyme leaves enzyme and recycled after reaction
- accepts more energy so it can assist in more reactions
- repeatedly loaded and unloaded, transferring from high and low energy levels

Question 14

what is the difference in the role of NADPH and ATP

Answer 14

NADPH: transfer hydrogen ions from LDP to LIP
ATP: carrier molecule that transfers energy from LDP to LIP
used in LIP to synthesise carbohydrate

Question 15

what is the role of NAD+

Answer 15

picks up H to become NADH
- needed for e- transport

Question 16

describe atp and adp cycling

Answer 16

⬆️atp during LDS as adp has phosphate group re-added
⬇️atp during LIS as it releases energy, losing phosphate group

Question 17

describe NADPH and NADH cycling

Answer 17

⬆️ NADPH during LDS-> loaded with H+ ions split from water
⬇️ NADPH during LIS-> used up and unloading H+ for glucose production

Question 18

what are enzyme inhibitors?

Answer 18

molecules that decrease enzyme function
- decreases interaction with intended substrate
= decrease or halt chemical pathway

Question 19

how do competitive inhibitors effect enzymes

Answer 19

• similar shape= binds to active site
• blocks substrate from binding= halt reaction

Question 20

how do non-competitive inhibitors effect enzymes

Answer 20

• bind to allosteric site (other location, non-active site)= change enzyme shape
• active site changed= substrate doesn’t fit/can’t bind to active site

Question 21

what is reversible inhibition

Answer 21

bonds formed between enzyme and inhibitor are weak= effect of inhibitor are not permanent
- slows r.o.r (does not stop it forever)

Question 22

how do you overcome reversible inhibition?

Answer 22

inhibitor and substrate compete for active site=> increase substrate conc
(effects cannot be overcome by increasing substrate conc in irreversible)

Question 23

what is irreversible inhibition

Answer 23

bonds formed between enzyme and inhibitor are strong= permanent
- stops enzyme catalysed reaction

Question 24

what is the effect of water availability on photosynthesis

Answer 24

(typically in excess=> doesn’t normally decrease)
-⬇️water in external environment= stomata closes to conserve water
- CO2 cannot enter= conc ⬇️ (used up)
- o2 cannot exit= conc ⬆️ (waste buildup
=> photorespiration ⬆️ photosynthesis⬇️

Question 25

effect of water availability on c3 plants

Answer 25

c3: imbalanced gases
- rubisco functioning= ⬇️photosynthesis, wasteful photorespiration

Question 26

effect of water availability on c4 plants

Answer 26

c4: less effected
- adaptions to combat photorespiration= maintain stable photosynthetic rates
- impacted under extreme water stress

Question 27

effect of water availability on cam plants

Answer 27

mechanisms to photosynthesis with stomata closed
= photosynthetic rate least affected

Question 28

effect of temperature on c3, c4 and cam plants

Answer 28

⬆️temp= evaporation (water loss effect)
- all plants impacted by temp (each step reliant on enzyme)
(optimal temp is higher in c4 and can plants= better adapted for hotter temps)