Bio topics 3 and 4

Question 1

What basic unit forms Carbohydrate molecules?

Answer 1

Simple sugars - Carbon, Hydrogen and Oxygen.

Question 2

Give an example of a simple sugar.

Answer 2

Glucose, Sucrose, Maltose, Galactose, Lactose, Fructose

Question 3

What larger molecules can simple sugar molecules form?

Answer 3

Sucrose (pair)

Starch, Glycogen and Cellulose (chain)

Question 4

What forms proteins?

Answer 4

Amino acids - Carbon, Hydrogen, Nitrogen and Oxygen.

Question 5

What simple unit makes up Lipids?

Answer 5

Fatty acids and Glycerol

Question 6

What is the function of protein?

Answer 6

Growth and repair

Make up Enzymes

Question 7

Why are Lipids important to the body?

Answer 7

They form cell membranes + other molecules in the body such as fats in storage cells.

Question 8

Describe the test for starch.

Answer 8

Drop iodine solution in substance

If starch is present, the colour changes from brown to dark blue.

Question 9

Describe the test for Glucose (reducing sugar).

Answer 9

Add Benedict's solution to the sample
Heat up in water bath
If reducing sugar is present, colour will change from blue to:
Green - small amount
Yellow - medium amount
orange - large amount

Question 10

Describe the test for proteins.

Answer 10

Add biuret solution to the sample

If protein is present colour will turn from blue to purple.

Question 11

Describe the test for fat.

Answer 11

Add ethanol in sample and shake

If fat is present, it will dissolve in ethanol to from a cloudy solution.

Question 12

What is an enzyme?

Answer 12

An enzyme is a biological catalyst made from proteins

Question 13

What is a catalyst?

Answer 13

A catalyst is a substance that changes the speed of a chemical reaction without being used up in the process.

Question 14

What are metabolic reactions?

Answer 14

Chemical reactions in the body’s cells that convert food to energy.

Question 15

What is a substrate?

Answer 15

A molecule which an enzyme joins with at the start of a reaction.

Question 16

What is a product?

Answer 16

A molecule formed at the end of a reaction.

Question 17

Describe enzyme action.

Answer 17

Enzymes have an active site
Active site shape is complementary to substrate’s shape. (Substrate fits into active site)
Substrate splits into two product molecules released from the enzyme.

Question 18

What is an enzyme-substrate complex.

Answer 18

A molecule formed when an enzyme and substrate join together.

Question 19

What enzyme breaks down carbohydrates?

Answer 19

Amylase - produced in the mouth.

Question 20

What enzyme breaks down proteins?

Answer 20

Protease - produced in stomach.

Question 21

What enzyme breaks down Lipids?

Answer 21

Lipase - produced in small intestine.

Question 22

What is meant by optimum temperature?

Answer 22

The temperature which enzymes work best at

Humans - around 37 degrees (body temp)

Question 23

What happens when the temp goes over the optimum?

Answer 23

Denatured.

The shape of the active site will change - no reaction.

Question 24

Temp increase will result in…

Answer 24

More kinetic energy, particles move faster, more successful collisions between enzyme and substrate.

Question 25

What is meant by optimum pH?

Answer 25

The pH which enzymes work best at.

Each enzyme has a different optimum pH.

Question 26

Describe the effect of pH on the enzyme.

Answer 26

Shape of enzyme depends on pH.

Shape of active site will change if pH changes too much.