4.1 Enzyme action

Question 1

Anabolic reactions

Answer 1

reactions that build up molecules

Question 2

catabolic reactions

Answer 2

reactions that break down molecules

Question 3

Metabolism

Answer 3

a chemical reaction involved in maintaining the living state of the cells in an organism
-> combination of anabolic and catabolic reactions

Question 4

Catalyst

Answer 4

a substance that speeds up reactions without changing the produced substance

Question 5

Metabolic pathway

Answer 5

sequence of enzyme controlled reactions

Question 6

Specificity

Answer 6

can only catalyse particular reactions

Question 7

Substrate:

Answer 7

a substance that binds to the enzyme

Question 8

Product

Answer 8

molecules formed by enzymes

Question 9

What are enzymes (5 points)

Answer 9

Enzymes are biological catalyst that help speed up metabolic reactions

They remain unchanged at the end of reactions and can be used again

Can catalyse large numbers of substrates into products

Increase a rate of reaction by lowering its activation energy

Can be intracellular or extra cellular

Can be prevented from working by molecules called enzyme inhibitors

Question 10

V max

Answer 10

maximum initial velocity or rate of enzyme-catalysed reaction
–> affected by temp, pressure, pH

Question 11

What is necessary for a reaction to occur?

Answer 11

Molecules move and collide randomly but molecules must collide in the RIGHT ORIENTATION
–> High temp & pressure increases the speed of molecules (more kinetic energy)
–>

Question 12

Lock and key hypothesis

Answer 12

The enzyme is a lock that only a specific key aka substrate can bind to
–> due to specificity of active site
This forms an enzyme substrate complex.
–> If product/s are formed then it is the enzyme-product complex

Substrate is held due to the R groups within the active site of the enzyme being able to form interactions with the substrate, forming temporary bonds

Question 12

Lock and key hypothesis

Answer 12

The enzyme is a lock that only a specific key aka substrate can bind to
–> due to specificity of active site
This forms an enzyme substrate complex.
–> If product/s are formed then it is the enzyme-product complex

Substrate is held due to the R groups within the active site of the enzyme being able to form interactions with the substrate, forming temporary bonds

Question 13

Intracellular (inside cells) enzymes

Answer 13

essential role in cells and organisms
–> synthesis of polymers from monomers e.g. polysaccharides from glucose

Hydrogen peroxide is broken down by catalase to oxygen and water, prventing accumulation

Question 14

What do all reactions need and what form does that substance take?

Answer 14

All reactions need substrates (raw materials which are constantly supplied to cell in demand
–> Nutrients are made in the form of polymers e.g. proteins or polysaccharides
–> large molecules cannot enter cells directly so they must be broken down first

Question 15

Extracellular (outside cells) enzymes

Answer 15

Enzymes are released from cells to break down large nutrient molecules into smaller molecules during digestion
–> both single celled and multicellular organisms rely on these enzymes to make use of polymers for nutrition

Question 16

How do single celled organisms like bacteria and yeast use extra cellular enzymes

Answer 16

they release enzymes into their immediate environment
==> breaks down larger molecules like proteins and smaller molecules are produced like amino acids and glucose (which are then absorbed by cells)

Question 17

How do multicellular organisms use extra cellular enzymes? e.g. humans

Answer 17

Even though food is eaten to gain nutrients, larger molecules still need to be further digested to fit into blood stream
–> in humans, enzymes like amylase and trypsin are extracellular

Question 18

What is amylase and trypsin?

Answer 18

Amylase produced in pancreas and saliva-producing gland
–> breaks down complex carbs into simpler ones, which are ultimately broken down into glucose

Trypsin is produced by the pancreas and helps break down dietary proteins in digestive tract

Question 19

Digestion of starch

Answer 19

Starts in mouth and continues to small intestine
1. Starch polymers are partially broken into maltose, disaccharide (done by amylase)
2. Maltose is then broken down into glucose (maltase, produced in small intestine)