Unit 10: Digestion and Absorption

Question 1

What is ingestion?

Answer 1

This is the mechanical breakdown of food and is the first stage of food processing

Question 2

What is digestion?

Answer 2

This is the process where molecules are broken down into small particles which are absorbed into cells

Question 3

What is a macromolecule?

Answer 3

These are large molecules such as fats, proteins and carbohydrates

Question 4

Why can macromolecules be used by animals?

Answer 4

They are too large to pass into cells
The macromolecules are not identical to the food consumed

Question 5

What does the process of digestion do to macromolecules?

Answer 5

Splits them into their component monomers

Question 6

What molecules are needed for plants to survive?

Answer 6

Carbon dioxide
Water
Other inorganic molecules

Question 7

What are the inorganic compounds absorbed through the soil called?

Answer 7

Mineral salts

Question 8

What can affect the availability of the salts in the soil?

Answer 8

pH

Question 9

What are macronutrients?

Answer 9

These are nutrients needed in large quantities for the plant to survive

Question 10

Can macronutrients be recycled?

Answer 10

Yes

Question 11

What happens if macronutrients cannot be recycled?

Answer 11

Fertilizers are required to maintain the macronutrients in the soil

Question 12

Why is nitrogen integral to plants?

Answer 12

They are macronutrients and a component of all proteins

Question 13

Why can nitrogen not diffuse through the leaves of a plant?

Answer 13

The molecule is too large

Question 14

What is nitrogen fixation?

Answer 14

This is the process of converting nitrogen to soluble compounds in the soil

Question 15

What can perform nitrogen fixation?

Answer 15

Bacteria
Cyanobacteria
Some fungi that has a symbiotic relationship with the plant roots

Question 16

What is a symbiotic relationship?

Answer 16

Two separate organisms supply the other with a vital service and vice versa

Question 17

How can carnivorous plants obtain nitrogen?

Answer 17

By digesting animals

Question 18

How do plants absorb mineral salts?

Answer 18

Through the water in between the soil

Question 19

How is the surface area to volume ratio increased on the roots?

Answer 19

By fine root hairs

Question 20

How does water enter the roots of the plant?

Answer 20

Osmosis

Question 21

Why is active transport required to bring salts into the root?

Answer 21

Because there is a higher concentration of salts inside the root than outside the root

Question 22

What is a heterotroph?

Answer 22

It is an organism that can create its own organic molecules

Question 23

What is chemical digestion?

Answer 23

This is the process of breaking down complex molecules into simple molecules via enzymes

Question 24

What is hydrolysis?

Answer 24

This process adds a water molecule to a food molecule

Question 25

What are the three types of digestive enzymes?

Answer 25

Amylases (carbohydrates) Proteases (proteins) Lipases (lipids)

Question 26

What is extracellular digestion?

Answer 26

This is where cells release enzymes into the small intestine

Question 27

What is intracellular digestion?

Answer 27

This is where a cell engulfs a food particle

Question 28

What is the mechanical breakdown of food?

Answer 28

This is the physical chewing and swallowing

Question 29

Why is the mechanical breakdown of food important?

Answer 29

Increases surface area to volume ratio so that enzymes can act at a faster rate

Question 30

What is the first stage of digestion?

Answer 30

Food enters the mouth

Question 31

What happens once food particles are in the mouth?

Answer 31

Amylase begins to work on the food

Question 32

What pH environment is created in the mouth?

Answer 32

Basic environment pH 6-8

Question 33

Why is saliva important?

Answer 33

Mixes with the food and protects the oesophagus from damage

Question 34

What is a bolus?

Answer 34

Food ball

Question 35

What are the reflexes that occur when a bolus is swallowed?

Answer 35

1. The bolus touches the pharynx (back of the tongue) 2. The upper and lower oesophageal sphincter open 3. The soft palate and epiglottis stop food from entering the respiratory tract 4. Breathing is stopped as the bolus is swallowed

Question 36

Where does the bolus travel after it exits the mouth?

Answer 36

Down the oesophagus

Question 37

What is peristalsis?

Answer 37

This is the squeezing of muscles to move particles along it

Question 38

What other product does the oesophagus produce?

Answer 38

Mucus

Question 39

Does the oesophagus produce enzymes?

Answer 39

No

Question 40

Why does the lower oesophageal sphincter close?

Answer 40

Stops food from returning to the mouth

Question 41

Where does the bolus go after it passes through the oesophagus?

Answer 41

Stomach

Question 42

What process occurs in the stomach?

Answer 42

Enzymes break the food particles into chyme

Question 43

What do glands in the stomach excrete to break down food?

Answer 43

Hydrochloric acid Pepsinogen Gastric lipase

Question 44

Where does the food travel after it exits the stomach?

Answer 44

Small intestine

Question 45

What are the villi?

Answer 45

These are small, finger-like tubes which line the walls of the small intestine and increase the amount of nutrients able to be absorbed

Question 46

What features of the villi help it to absorb nutrients?

Answer 46

The lining is thin - Allowing for faster absorption Well supplied with blood - transfer nutrients out quickly

Question 47

What is the first section of the small intestine called?

Answer 47

Duodenum

Question 48

What does the duodenum release?

Answer 48

It releases pancreatic enzymes and bile