B3 Organisation and Digestion

Question 1

What is a system in biology?

Answer 1

A group of things working together as part of a mechanism.

Question 2

What is a tissue?

Answer 2

A group of the same type of cells.

Question 3

What is an organ?

Answer 3

A group of tissues working together

Question 4

What is an organ system?

Answer 4

A group of organs working together to do a specific job.

Question 5

What are the 4 main types of tissue in the body

Answer 5

Connective, epithelial, muscle, and nervous tissue.

Question 6

How many organ systems are in the body?

Answer 6

11 organ systems.

Question 7

What does the skeletal system do?

Answer 7

Supports the body, protects organs, and helps us move.

Question 8

What does the muscular system do?

Answer 8

Helps us move and keeps us warm.

Question 9

What does the cardiovascular system do?

Answer 9

Moves blood around the body.

Question 10

What is digestion?

Answer 10

Breaking large insoluble molecules into small soluble ones.

Question 11

What are the main digestive organs?

Answer 11

Mouth, oesophagus, stomach, small intestine, large intestine, rectum, anus.

Question 12

What are the supporting digestive organs?

Answer 12

Salivary glands, liver, pancreas.

Question 13

What happens in the mouth?

Answer 13

Food enters and is broken down by teeth.

Question 14

What does the oesophagus do?

Answer 14

Pushes food to the stomach using muscle movements.

Question 15

What happens in the stomach?

Answer 15

Food is mixed and broken down by acid and churning.

Question 16

What happens in the small intestine?

Answer 16

Digestion continues and nutrients are absorbed.

Question 17

What happens in the large intestine?

Answer 17

Water is absorbed and faeces is formed

Question 18

What is the role of the rectum?

Answer 18

Stores faeces.

Question 19

What does the anus do?

Answer 19

Releases faeces from the body.

Question 20

What does the liver do?

Answer 20

Makes bile to break up fats.

Question 21

What does the pancreas do?

Answer 21

Makes and releases digestive enzymes.

Question 22

What is a food test?

Answer 22

A test where a reagent is added to food to detect nutrients.

Question 23

What is a macromolecule?

Answer 23

A large molecule made from smaller units called monomers.

Question 24

What are the three macromolecules?

Answer 24

Carbohydrates, proteins and lipids (fats)

Question 25

What are carbohydrates made of?

Answer 25

Glucose monomers.

Question 26

What breaks down carbohydrates?

Answer 26

Carbohydrase enzymes like amylase.

Question 27

What is starch broken down by?

Answer 27

Amylase

Question 28

What are proteins made of?

Answer 28

Amino acids.

Question 29

What breaks down proteins?

Answer 29

Protease enzymes.

Question 30

What are lipids made of?

Answer 30

Lipase enzymes.

Question 31

Starch test: What do you use and what is the result?

Answer 31

Iodine — turns blue-black if starch is present.

Question 32

Protein test: What do you use and what is the result?

Answer 32

Biuret — turns purple if protein is present.

Question 33

Lipid test: What do you use and what is the result?

Answer 33

Ethanol — cloudy if lipids are present.

Question 34

Reducing sugar test: What do you use and what is the result?

Answer 34

Benedict’s — turns from blue to brick red when heated.

Question 35

What is an enzyme?

Answer 35

A biological catalyst that speeds up reactions in the body.

Question 36

What is a catalyst?

Answer 36

A substance that speeds up a reaction without being used up.

Question 37

How do enzymes work?

Answer 37

They fit with a substrate like a lock and key.

Question 38

What is the 'lock and key theory'?

Answer 38

The enzyme's active site fits exactly with its specific substrate.

Question 39

What is meant by ‘optimum temperature’ for an enzyme?

Answer 39

The temperature where the enzyme works best.

Question 40

What happens if the temperature is too high for an enzyme?

Answer 40

The enzyme denatures and can’t work.

Question 41

What does denatured mean?

Answer 41

The enzyme's shape changes so it can’t bind to its substrate.

Question 42

What is meant by ‘optimum pH’?

Answer 42

The pH where the enzyme works best.

Question 43

What happens if pH is too high or too low?

Answer 43

The enzyme denatures and stops working.

Question 44

Why is the digestive system efficient?

Answer 44

It uses special structures and enzymes to break food down quickly.

Question 45

Why are enzymes specific?

Answer 45

They only work with one type of substrate.

Question 46

What does amylase do?

Answer 46

Breaks starch into sugars.

Question 47

Where is amylase found?

Answer 47

In saliva and the small intestine.

Question 48

What conditions does amylase need?

Answer 48

Neutral pH and body temperature.

Question 49

What does protease do?

Answer 49

Breaks proteins into amino acids.

Question 50

What is pepsin?

Answer 50

A type of protease found in the stomach.

Question 51

What does pepsin need to work?

Answer 51

Acidic conditions (low pH).

Question 52

Where else is protease found?

Answer 52

In the small intestine (released by the pancreas).

Question 53

What does lipase do?

Answer 53

Breaks lipids into glycerol and fatty acids.

Question 54

Where does lipase work?

Answer 54

Neutral pH and body temperature.

Question 55

What does bile do?

Answer 55

Breaks lipids into small droplets (emulsifies them) and neutralises acidic food from the stomach.

Question 56

Why is bile useful?

Answer 56

It increases the surface area for lipase to work.

Question 57

What happens to the enzyme if it denatures?

Answer 57

The substrate wont fit into the changed active site.

Question 58

What are the two types of digestion?

Answer 58

Mechanical digestion and chemical digestion.

Question 59

What is mechanical digestion? What is mechanical digestion?

Answer 59

Physical breakdown of food into smaller pieces.

Question 60

What are some examples of mechanical digestion?

Answer 60

Chewing with teeth, churning in the stomach

Question 61

Why is mechanical digestion important?

Answer 61

It increases surface area for enzymes to work on.

Question 62

What is chemical digestion?

Answer 62

Breaking down food using enzymes and acids.

Question 63

Examples of chemical digestion?

Answer 63

Enzymes like amylase, protease, lipase breaking food down.

Question 64

What helps chemical digestion in the stomach?

Answer 64

Hydrochloric acid and enzymes like pepsin.

Question 65

Why does the stomach need a mucus lining?

Answer 65

To protect its walls from being damaged by hydrochloric acid and prevent ulcers (painful).

Question 66

What is the duodenum?

Answer 66

The first part of the small intestine where bile and enzymes are added to food.

Question 67

What happens to the acidic food from the stomach in the duodenum?

Answer 67

It is neutralised by bile so enzymes can work properly.

Question 68

Why is neutralising stomach acid important for digestion?

Answer 68

Why is neutralising stomach acid important for digestion?

Question 69

What is the optimum temperature for most enzymes in the human body?

Answer 69

Around 37°C (body temperature).

Question 70

Why do enzymes work best at 37°C?

Answer 70

It's the normal body temperature, giving enzymes enough kinetic energy to work without denaturing.

Question 71

What is the optimum pH for enzymes in the mouth (salivary glands)?

Answer 71

Around pH 7 (neutral).

Question 72

What enzyme is found in the mouth and salivary glands?

Answer 72

Amylase — it breaks down starch into sugars.

Question 73

What is the pH in the stomach?

Answer 73

Very acidic — around pH 1.5 to 2.

Question 74

Why is the stomach acidic?

Answer 74

Hydrochloric acid helps break down food and creates the right pH for pepsin.

Question 75

What enzyme works in the stomach and what is its pH?

Answer 75

Pepsin, works best at pH 2 (acidic).

Question 76

What is the role of mucus in the stomach?

Answer 76

To protect the stomach lining from acid and prevent ulcers.

Question 77

What is the pH in the small intestine (duodenum)?

Answer 77

Slightly alkaline — around pH 7.5 to 8

Question 78

Why is the small intestine alkaline?

Answer 78

Bile neutralises the acidic food from the stomach so enzymes can work properly.

Question 79

What organ produces bile and what is its pH role?

Answer 79

The liver produces bile, which is alkaline and neutralises stomach acid.

Question 80

What pH do lipase and pancreatic enzymes work best at?

Answer 80

Neutral to alkaline pH (around 7 to 8).

Question 81

What enzymes are released by the pancreas into the small intestine?

Answer 81

Lipase, amylase, and proteases.

Question 82

What is the pH of the pancreas secretions?

Answer 82

Around pH 8 (alkaline).