Chapter 5C Digestive System

Question 1

What do animals need to survive, live, and reproduce?

Answer 1

Organic molecules for energy and building biomacromolecules.

Question 2

What are animals that consume other organisms called?

Answer 2

Heterotrophs.

Question 3

What is the purpose of physical (mechanical) digestion?

Answer 3

To increase surface area for chemical digestion.

Question 4

What are examples of physical digestion?

Answer 4

Biting, chewing, muscular contractions, mixing with digestive juices.

Question 5

What is chemical digestion?

Answer 5

Breaking large molecules into smaller ones using enzymes or stomach acid.

Question 6

What are the four stages of digestion?

Answer 6

Ingestion, Digestion, Absorption, Egestion (Elimination).

Question 7

What happens during ingestion?

Answer 7

Food is taken in, chewed, mixed with saliva, and formed into a bolus.

Question 8

What happens during digestion?

Answer 8

Food is broken down physically and chemically in the digestive tract.

Question 9

What happens during absorption?

Answer 9

Small molecules are absorbed into the bloodstream from the digestive tract.

Question 10

What happens during egestion?

Answer 10

Undigested material is expelled as faeces.

Question 11

What are organic molecules made of?

Answer 11

Carbon atoms.

Question 12

What are the 4 major groups of organic biomolecules?

Answer 12

Nucleic acids, lipids, proteins, carbohydrates.

Question 13

What are nucleic acids made of and what do they do?

Answer 13

Nucleotides; store genetic information.

Question 14

What are lipids made of and what is their role?

Answer 14

Glycerol and fatty acids; store energy.

Question 15

What are carbohydrates made of and what is their role?

Answer 15

Saccharides (simple sugars); main energy source.

Question 16

What are proteins made of and what is their function?

Answer 16

Amino acids; build cells, receptors, and enzymes.

Question 17

What are vitamins and what do they do?

Answer 17

Organic molecules required in small amounts for various functions.

Question 18

Give examples of vitamins

Answer 18

Vitamins A, B, C, D, K.

Question 19

What are minerals and why are they important?

Answer 19

Inorganic elements for bone building and nerve function.

Question 20

Give examples of essential minerals

Answer 20

Calcium, magnesium, potassium, sodium, chloride.

Question 21

What are enzymes?

Answer 21

Proteins that speed up chemical reactions (biological catalysts).

Question 22

How do enzymes work?

Answer 22

They lower the activation energy for reactions.

Question 23

Are enzymes used up in reactions?

Answer 23

No, they are unchanged and reusable.

Question 24

What is an enzyme’s active site?

Answer 24

The specific site that matches and binds to a substrate.

Question 25

What do digestive enzymes do?

Answer 25

Break down food macromolecules for absorption.

Question 26

Match enzyme to substrate and product: Lipase

Answer 26

Lipids → Fatty acids and glycerol.

Question 27

Match enzyme to substrate and product: Protease

Answer 27

Proteins → Amino acids.

Question 28

Match enzyme to substrate and product: Amylase

Answer 28

Carbohydrates → Simple sugars (monosaccharides).

Question 29

What is peristalsis?

Answer 29

Wave-like muscular contractions that move food through the digestive tract.

Question 30

What controls movement in the digestive tract?

Answer 30

Muscular rings called sphincters.

Question 31

What is the path food follows through the digestive system?

Answer 31

Mouth → Oesophagus → Stomach → Small intestine → Large intestine.

Question 32

What is the function of the oral cavity (mouth)?

Answer 32

Mechanical digestion (chewing); enzymes in saliva begin digestion.

Question 33

What do salivary glands do?

Answer 33

Produce and release saliva into the mouth and oesophagus.

Question 34

What is the oesophagus?

Answer 34

A muscular tube connecting mouth and stomach; moves bolus by peristalsis.

Question 35

What happens in the stomach?

Answer 35

Food is mixed (physical digestion); pepsin and acid begin protein digestion.

Question 36

What protects the stomach from its own acid?

Answer 36

Mucus lining.

Question 37

What is chyme?

Answer 37

Partially digested, acidic food leaving the stomach.

Question 38

What does the liver do?

Answer 38

Produces bile, regulates metabolism, detoxifies, and stores glycogen.

Question 39

What is the function of bile?

Answer 39

Begins the breakdown of fats.

Question 40

What does the gallbladder do?

Answer 40

Stores and concentrates bile before release into the small intestine.

Question 41

What does the pancreas do?

Answer 41

Produces digestive enzymes and bicarbonate; regulates blood sugar.

Question 42

What are the three parts of the small intestine?

Answer 42

Duodenum, jejunum, ileum.

Question 43

What is the main function of the small intestine?

Answer 43

Absorption of nutrients into the bloodstream.

Question 44

Where does most chemical digestion and nutrient absorption occur?

Answer 44

Small intestine.

Question 45

What are the three parts of the large intestine?

Answer 45

Cecum, colon, rectum.

Question 46

What is absorbed in the large intestine?

Answer 46

Water, vitamins, and minerals.

Question 47

What is the function of the rectum?

Answer 47

Stores faeces before elimination.

Question 48

What is the function of the anus?

Answer 48

Expels faeces from the body.

Question 49

Why is surface area important in digestion?

Answer 49

Increases efficiency of chemical digestion and absorption.

Question 50

What structures increase surface area in the small intestine?

Answer 50

Villi and microvilli.

Question 51

What are villi?

Answer 51

Finger-like projections in the small intestine for nutrient absorption.

Question 52

What are microvilli?

Answer 52

Tiny folds on epithelial cells of villi that further increase surface area.

Question 53

What is the gut microbiome?

Answer 53

Microorganisms in the digestive system that aid digestion.

Question 54

What is the relationship between animals and their gut microbes?

Answer 54

Symbiotic: microbes help digest food, animals provide a home.

Question 55

Why is digesting cellulose difficult?

Answer 55

It is tough and takes a long time to break down.

Question 56

What are hindgut fermenters?

Answer 56

Animals with large cecums where plant matter is fermented (non-ruminants).

Question 57

What are foregut fermenters?

Answer 57

Animals with multi-chambered stomachs; first chamber is fermentation site (ruminants).