3rd Form Topic Test 3

Question 1

What is metabolism

Answer 1

The sum of all reactions in a cell or the body

Question 2

What is the digestive system

Answer 2

An example of an organ system in which several organs work together to digest and absorb food

Question 3

Mouth

Answer 3

Teeth cut and grind food, while the tongue mixes it with salivary enzymes that chemically breaks down the food

Question 4

Oesophagus

Answer 4

Moves the bolus down to the stomach, using wave-like muscular contractions, (peristalsis) to push the food along

Question 5

Bolus

Answer 5

Chewed up food mixed with saliva

Question 6

Stomach (4)

Answer 6

store food, mix it with strong acid and enzymes (like protease) to start breaking down proteins, and churn it into a mush, killing germs along the way

Question 7

Small intestine (3)

Answer 7

Complete food break down, absorb nutrients and water, and moves digested food along the GI tract

Question 8

Large intestine (3)

Answer 8

Absorb water and electrolytes from indigestible food matter, turning liquid waste into solid feces and then stores it and eliminates it from the body

Question 9

Importance of sugars (3)

Answer 9

Main fuel for cells,
broken down into glucose for immediate energy
or stored as glycogen/fat

Question 10

Amino acids (4)

Answer 10

Link together to form proteins, essential for cell growth, repair and function

Question 11

Fatty acids & glycerol (4)

Answer 11

Stored as flat for long-term energy, form cell membranes and provide thermal insulation and cushion organs

Question 12

What are sugars

Answer 12

Carbohydrates

Question 13

What are amino acids?

Answer 13

Proteins

Question 14

What are fatty acids and glycerol

Answer 14

Lipids (fats)

Question 15

What is energy from respiration used for

Answer 15

used for enzyme-controlled processes of metabolism that synthesise new molecules

Question 16

What 5 things does metabolism include?

Answer 16

glucose into starch, glycogen and cellulose
Formation of lipid molecules from 1 glycerol and 3 fatty acids
Use of glucose + nitrate ions to form amino acids, (used to make proteins)
Respiration
Breakdown of excess proteins to form urea for excretion

Question 17

How do enzymes help metabolism?

Answer 17

Enzymes control metabolic reactions so they can occur quickly at body temperature

Question 18

What are enzymes

Answer 18

Proteins

Question 19

Explain why pH affects enzyme activity

Answer 19

Extreme acidity or alkalinity changes the shape of the enzymes active site therefore substrate can’t fit which slows and/or stops the reaction

Question 20

What is the process called when a enzymes active site is changed? Therefore the substrate can’t fit?

Answer 20

Denaturation (denatured)

Question 21

Explain why temperature affects enzyme activity

Answer 21

low temperatures slow reactions due to less kinetic energy,
increasing temperatures boost activity by creating more collisions, but exceeding an OPTIMUM TEMPERATURE causes enzymes to denature, losing shape and function

Question 22

What does every enzyme have

Answer 22

An optimum pH

Question 23

Example of rate calculation: if 15g of substrate is used in 2hrs, the rare is?

Answer 23

15 divided by 2 = 7.5g per hour

Question 24

Why do enzymes catalyse specific reactions

Answer 24

because the shape of their active site is complementary to their substrate

Question 25

What is the “lock and key” theory

Answer 25

states that a substrate fits exactly into the enzyme’s active site, allowing the reaction to occur

Question 26

What is another enzyme model apart from the lock and key theory

Answer 26

The induced fit model

Question 27

Explain the induced fit model

Answer 27

When a substrate approaches, the enzyme's active site isn't perfectly pre-formed; it flexes and adjusts its shape to embrace the substrate enzyme's active site, moulding around it for a perfect fit, unlike the rigid “lock and key” idea

Question 28

What do digestive enzymes do

Answer 28

break down large, insoluble food molecules into small, soluble molecules that can be absorbed into the bloodstream

Question 29

What enzyme breaks down carbohydrates

Answer 29

Carbohydrases

Question 30

What do carbohydrates break carbs into

Answer 30

Simple sugars

Question 31

What enzymes break down starch

Answer 31

Amylase

Question 32

What enzyme breaks down proteins

Answer 32

Proteases

Question 33

What are proteins broken down into

Answer 33

Amino acids

Question 34

What enzyme breaks down lipids (fats)

Answer 34

Lipases

Question 35

What are lipids broken down into

Answer 35

Fatty acids + glycerol

Question 36

What are digestion products used for? (2)

Answer 36

used to build new carbohydrates, lipids and proteins. Some glucose is used in respiration

Question 37

Where is bile made and stored

Answer 37

Bile is made in the LIVER and stored in the GALL BLADDER

Question 38

Is bile an acid or alkaline and what does it neutralise?

Answer 38

It is an ALKALINE and neutralises HYDROCHLORIC ACID from the stomach

Question 39

What does bile increase (2)

Answer 39

Increases surface area Increases the rate of digestion by lipase

Question 40

What does bile do to fat

Answer 40

emulsifies or mixes together the fats in our food. That means they break large fat globules into smaller particles