The Digestive System

Question 1

Digestion

Answer 1

The breaking down of large, insoluble molecules of food into smaller, soluble molecules that can be absorbed into the bloodstream and used by the body

Question 2

Example of physical digestion

Answer 2

Chewing

Question 3

3 types of chemical digestion

Answer 3

-Broken down by enzymes
-Digestion by stomach acids
-Fats are emulsified

Question 4

Function of stomach acid

Answer 4

-Breaks chemical bonds
-Kills microbes take in with the food
-Provide correct pH for enzymes

Question 5

What is physical digestion

Answer 5

-It is the first stage of digestion
-It is quick, and It is where large chunks of food are broken down into smaller bits, first by chewing

Question 6

Chemical digestion

Answer 6

-It is the second stage of digestion
-It is slower than physical digestion because it is where smaller insoluble molecules are chemically broken down into even smaller, soluble molecules
-This is mostly done by enzymes

Question 7

Why is digestion necessary?

Answer 7

-To break down large insoluble molecules into small soluble molecules
-This is to make sure that molecules can be absorbed through the partially permeable membrane and into the blood stream

Question 8

Similarities between physical and chemical digestion

Answer 8

Both increase the surface area of food

Question 9

Differences between physical and chemical digestion

Answer 9

-Chemical digestion uses enzymes, but physical digestion doesn’t
-Chemical digestion uses stomach acid but physical digestion doesn’t
-Chemical digestion uses bile but physical digestion doesn’t
-Physical digestion involves chewing or churning food, but chemical digestion doesn’t
-Chemical digestion converts large insoluble molecules into smaller soluble ones, but physical digestion doesn’t

Question 10

Teeth

Answer 10

-Physically digest food into smaller pieces to aid chemical digestion
- Different teeth have different roles, eg.incisors for tearing, molars for grinding

Question 11

Tongue

Answer 11

-Tongues is a muscle
-Important for speaking (in humans)
- Help to move food to the back of the mouth so you can swallow it
- Have taste buds

Question 12

Salivary glands

Answer 12

• Help to lubricate food to make it easier to swallow
• Contain an enzyme called amylase

Question 13

Oesophagus

Answer 13

• Food is passed down the oesophagus to the stomach by a process called peristalsis
• The muscle tissue in the wall of the oesophagus contract behind the food and pushes it along

Question 14

Stomach

Answer 14

• Churns food to mix it with digestive juices
• Produce digestive juices

Question 15

What are the two parts of the small intestine called?

Answer 15

Duodenum and the ileum

Question 16

Duodenum

Answer 16

Involved in digestion

Question 17

Ileum

Answer 17

Where digested food is absorbed into the blood

Question 18

Large intestine

Answer 18

• Reabsorbes water from the waste material

Question 19

Adaptations of the small intestine

Answer 19

• Villi
• Microvilli
• Longer length (6-7m)
• Highly- folded surface
• Mitochondria

Question 20

Villi

Answer 20

Finger-like projections to increase the surface area

Question 21

Microvilli

Answer 21

Cells covering the Villi that have tiny projecting folds to increase the surface area

Question 22

Mitochondria in small intestine

Answer 22

They line the Villi and provide energy to enable them to absorb substances by active transport

Question 23

Highly folded surface area

Answer 23

Increases surface area with digested food

Question 24

Pancreas

Answer 24

Produces enzymes that are released in the small intestine

Question 25

Liver

Answer 25

Bile is made here

Question 26

Gall bladder

Answer 26

Bile is stored here

Question 27

Large intestine

Answer 27

Reabsorbes water

Question 28

Rectum

Answer 28

Stores waste

Question 29

How do Adaptations of Villi help with absorption in digestion?

Answer 29

• Rich blood supply
• Large surface area
  -Thin walls

Question 30

Rich blood supply in Villus

Answer 30

Produces a steep concentration gradient for efficient diffusion

Question 31

Thin walls in Villus

Answer 31

So there is only a short distance across where diffusion takes place

Question 32

What are the uses of products in digestion?

Answer 32

• Sugars can be used to build new carbohydrates in our cells
• Fatty acids and glycerol can be used to build new lipids/Fats in our cells
• Amino acids can be used by ribosomes to build new proteins in our cells