Digestion

Question 1

2 types of digestion

Answer 1

Chemical digestion - the chemical breakdown of food molecules
Occurs in most parts of the alimentary canal except for the large intestine and oesophagus

Mechanical digestion - the physical breakdown of food pieces into into smaller pieces
Occurs in the stomach, mouth and small intestine

Question 2

Mechanical digestion

Answer 2

Mouth - teeth cut, tear and grind
Stomach - churning to break down further
Small intestine- bile salts emulsify fats into smaller droplets

Question 3

Mechanical digestion

Answer 3

The smaller the food is, it will still be the same volume but have a larger surface area = more chemical reactions with the villi

Question 4

Chemical digestion

Answer 4

Large complex molecules to smaller simple molecules

Carbohydrates = monosaccharides (glucose, fructose and galactose)

Protein = peptides and AA ( amino acids )

Lipids = fatty acids and glycerol

Nucleic acids = nucleotides

Question 5

Chemical digestion

Answer 5

Starch glycogen - uses salivary amylase =
Disaccharide - uses maltase (maltose), sucrase (sucrose), lactase (lactose) =
Monosaccharide - 2 glucose, 1 glucose and 1 fructose, 1 glucose and 1 galactose

Protein - uses pepsin
triglyceride - uses lipase

Question 6

Mouth

Answer 6

Mechanical digestion
Break food into smaller pieces by mastication

Chemical digestion
Saliva = salivary amylase begins to starch digestion

Question 7

Stomach

Answer 7

Mechanical digestion
Waves of food contraction churn food, producing chyme

Chemical digestion
Gastric juice =
Hydrochloride acid = kills bacteria
Pepsin = polypeptide

Question 8

Small intestine

Answer 8

Mechanical digestion
Muscular contractions churn food
Bile salts emulsify lipids

Chemical digestion
Pancreatic juice =
Amylase = starch into disaccharides
Protease = proteins into peptides
Lipase = lipids into fatty acids and glycerin
Nuclease = DNA/RNA into nucleotides

Intestinal juices =
Amylase = disaccharides into simple sugars
Protease = peptides into amino acids
Lipase = lipids into fatty acids and glycerol