6.1 DIGESTION AND ABSORPTION

Question 1

ESSENTIAL IDEA

Answer 1

the structure of the wall of the small intestine allows it to move, digest and absorb food

Question 2

ANNOTATED DIAGRAM OF DIGESTIVE SYSTEM

Answer 2

https://image.slidesharecdn.com/biok6-160120014802/95/bioknowledgy-presentation-on-61-digestion-and-absorption-5-638.jpg?cb=1453254838

Question 3

MOUTH

Answer 3

chewing (mechanical digestion)

saliva moistens the food to make a bolus for swallowing

salivary amylase begins chemical digestion of starch

Question 4

OESOPHAGUS

Answer 4

a wave of muscle contractions (peristalsis) pushes the bolus into the stomach

Question 5

DIGESTION ORDER

Answer 5

1. mouth
2. oesophagus
3. stomach
4. duodenum (S.I)
5. Ileum (S.I)
6. large intestine
7. anus/ egestion

Question 6

STOMACH

Answer 6

muscular contractions continue mechanical digestion

acid kills bacteria

pepsin begins digestion of proteins

Question 7

DUODENUM (S.I)

Answer 7

bile from the liver and gall bladder neutralises acid and emulsifies fats

pancreatic amylase and lipase digest carbohydrates and fats

trypsin digest polypeptides to AA

Question 8

ILEUM (S.I)

Answer 8

lower half of small intestine absorbs nutrients into the blood via the villi

Question 9

ANUS

Answer 9

egestion: faeces containing undigested food, dead cells and other waste, is forced out of the anus

Question 10

PERISTALSIS AND SI

Answer 10

a wave of muscle contractions keeps the mixture of digested and undigested food moving through the intestine

Question 11

PERISTALSIS

Answer 11

contraction of circular and longitudinal muscles of the small intestines mixes the food with enzymes and moves it along the gut

Question 12

LARGE FOOD MOLECULES BEOFRE THEY CAN BE ABSORBED NEED TO BE

Answer 12

digested: hydrolysis

Question 13

LARGER MOLECULES ARE

Answer 13

large food M are usually insoluble and too large for diffusion across membranes into the blood

Question 14

PRODUCTS OF DIGESTION ARE

Answer 14

usually soluble

small enough for absorption into the blood and later assimilation into the tissue

Question 15

HYDROLYSIS

Answer 15

‘water splitting’

reaction used to break down large organic molecules CPL

enzymes are needed

Question 16

ENZYME

Answer 16

globular protein that increase the rate of biochemical reaction by lowering the activation energy threshold

aka: biological catalyst

Question 17

DIGESTIVE ENZYMES

Answer 17

released into the gut from glands and are use in catabolic reactions- they break down larger molecuels

Question 18

USE OF DIGESTIVE ENZYMES

Answer 18

by lowering the activation energy of the reaction, the reaction does not require high temperatures

this is ideal in living things as high temperatures would cause damaged to cells and proteins

by using enzymes, reactions can occur more quickly at body temperatures

Question 19

3 MAIN TYPES OF DIGESTIVE ENZYMES

Answer 19

amylase

protease

lipase

Question 20

AMYLASE

Answer 20

breaks down carbohydrates

Question 21

AMYLASE EXAMPLE

Answer 21

salivary amylase

Question 22

AMYLASE SUBSTRATE

Answer 22

starch

Question 23

AMYLASE PRODUCT

Answer 23

maltose

Question 24

AMYLASE SOURCE

Answer 24

mouth

Question 25

AMYLASE OPTIMUM PH

Answer 25

7-7.8

Question 26

PROTEASE

Answer 26

breaks down polypeptides

Question 27

PROTEASE EXAMPLE

Answer 27

pepsin

Question 28

PROTEASE SUBSTRATE

Answer 28

polypeptides

Question 29

PROTEASE PRODUCT

Answer 29

amino acids

Question 30

PROTEASE SOURCE

Answer 30

stomach

Question 31

PROTEASE OPTIMUM PH

Answer 31

2

Question 32

LIPASE

Answer 32

breaks down fats and lipids

Question 33

LIPASE EXAMPLE

Answer 33

pancreatic lipase

Question 34

LIPASE SUBSTRATE

Answer 34

triglyceride

Question 35

LIPASE PRODUCT

Answer 35

fatty acids and glycerol

Question 36

LIPASE SOURCES

Answer 36

pancreas delivered to S.I

Question 37

LIPASE OPTIMUM PH

Answer 37

7.2-7.5

Question 38

PANCREAS

Answer 38

synthesizes 3 main types of enzymes: amylase lipase protease

Question 39

PANCREATIC JUICE

Answer 39

containing the enzymes is released into the upper region of the S.I (duodenum) via the pancreatic duct

Question 40

FINAL STAGES OF DIGESTION OCCUR?

Answer 40

small intestine

Question 41

PANCREATIC DUCT

Answer 41

carries pancreatic juice from pancreas to S.I

Question 42

SMALL INTESTINE AND ITS LAYERS

Answer 42

mucosa submucosa muscular layer serosa epithelial cells

Question 43

MUCOSA

Answer 43

inner lining, includes villi

Question 44

SUBMUCOSA

Answer 44

connective tissue | between mucosa and muscle

Question 45

MUSCULAR LAYER

Answer 45

inner circular and outer longitudinal muscles perform peristalsis

Question 46

SEROSA

Answer 46

protective outer layer

Question 47

EPITHELIAL CELLS

Answer 47

single outer layer of cells on each villus

Question 48

ADAPTATIONS TO ABSORPTION

Answer 48

villi increases the surface area of epithelium over which absorption is carried out

Question 49

VILLI- EPITHELIAL CELLS

Answer 49

single cell layer of epithelial cells = short path for diffusion

Question 50

MICROVILLI

Answer 50

on the surface of each cell increases the surface area even further

Question 51

VILLI-LACTEALS

Answer 51

allow for rapid absorption and transport of lipids

Question 52

VILLI-CAPILLARIES

Answer 52

close to epithelium short path of diffusion rich supply of blood

Question 53

VILLI- RICH BLOOD SUPPLY

Answer 53

maintains concentration gradients between lumen and blood

Question 54

MEMBRANE TRANSPORT | LIPIDS

Answer 54

simple diffusion non-polar and can pass freely through the hydrophobic core of the plasma membrane into the epithelial cells (down the concentration gradient)

Question 55

MEMBRANE TRANSPORT | FRUCTOSE, VITAMINS

Answer 55

facilitated diffusion water soluble/ hydrophilic M use channels proteins to pass phospholipid bilayer and enter the epithelial cells (down conc gr.)

Question 56

MEMBRANE TRANSPORT | GLUCOSE, AA, MINERAL IONS

Answer 56

protein pumps use ATP to move M against conc gr into epithelial cells

Question 57

MEMBRANE TRANSPORT | ANTIBODIES FROM BREAST MILK

Answer 57

the plasma membrane folds inwards to form vesicles to absorb larger molecules without digesting them

Question 58

DIGESTION OF STARCH INTO GLUCOSE

Answer 58

starch consists of amylose and amylopectin amylase breaks amylose into maltose monomers dextrinase breaks amylopectin into glucose monomers maltase digests maltose into glucose monomers

Question 59

TRANSPORT OF THE PRODUCTS OF STARCH DIGESTION TO THE LIVER

Answer 59

the digested glucose is absorbed and transported to various body tissues

Question 60

TRANSPORT OF THE PRODUCTS OF STARCH DIGESTION TO THE LIVER 1

Answer 60

glucose is co-transported with Na ions into the epithelial cells of the villus

Question 61

TRANSPORT OF THE PRODUCTS OF STARCH DIGESTION TO THE LIVER 2

Answer 61

glucose moves by facilitated diffusion into the lumen of the villus

Question 62

TRANSPORT OF THE PRODUCTS OF STARCH DIGESTION TO THE LIVER 3

Answer 62

glucose then diffuses a short distance into the adjacent capillaries where it dissolves into the blood plasma

Question 63

TRANSPORT OF THE PRODUCTS OF STARCH DIGESTION TO THE LIVER 4

Answer 63

blood in the capillaries move to venules then to the hepatic portal vein which transports the glucose to the liver

Question 64

TRANSPORT OF THE PRODUCTS OF STARCH DIGESTION TO THE LIVER 5

Answer 64

the liver absorbs excess glucose which is converted to glycogen for storage

Question 65

DIALYSIS TUBING

Answer 65

to model absorption of digested food in the intestine tube is semi- permeable