digestion and absorption

Question 1

what makes up a good plate?

Answer 1

-1/3 rd fruit and veg
-1/3rd carb rich
-half protein
-half healthy fats

Question 2

carbohydrates?

Answer 2

-energy source
-bread rice pasta potatoes

Question 3

protein?

Answer 3

-repair and growth
-meat fish dairy nuts

Question 4

fat?

Answer 4

-long term energy store
-insulation
-meat cheese cream fish avocado

Question 5

vitamins?

Answer 5

A- vision, liver sweet potato
C- antioxidant, citrus
D - Ca absorption, oily fish
B- vegetables

Question 6

minerals?

Answer 6

ca - bone mineralisation, milk
fe - oxygen transport, red meat
K - banana

Question 7

fibre?

Answer 7

effective bowel movement, plants, fruit veg, nuts, cereals

Question 8

what are triglycerides?

Answer 8

glycerol and 3 fatty acids, 90% of fat in the diet, can be saturated or unsaturated.

Question 9

phospholipids?

Answer 9

-present in plasma membrane
-composed of 2 fatty acid chains

Question 10

what is cholesterol?

Answer 10

present in the plasma membrane, also forms basis for synthesis of other hormones

Question 11

where can we get saturated fats?

Answer 11

-mainly animal foods
-meat fat, butter, cream and cheese

Question 12

where can we get unsaturated fats?

Answer 12

-mainly from plants
-olive and rape seed, nuts

Question 13

where can we get cholesterol?

Answer 13

-plants and animals
-dairy products
-palm and coconut oil

Question 14

what happens if we get too much fats?

Answer 14

-atherosclerosis (can lead to heart attack and stroke)
-obesity

Question 15

what are the 9 essential amino acids?

Answer 15

body cant synthesise them
-phenylalanine
-valine
-tryptophan
-threonine
-isoleucine
-methionine
-histidine
-leucine
-lysine

Question 16

what are the common carbs?

Answer 16

monosaccharides- glucose, fructose, galactose
disaccharides - sucrose, maltose and lactose
polysaccharides -starch

Question 17

what is digestion?

Answer 17

process by which food is broken down into components simple enough to be absorbed in the intestine

Question 18

what enzymes aid digestion?

Answer 18

secreted by;
-glandular cells in mouth
-chief cells in stomach
-endocrine cells of pancreas
-enzymes bound to the apical membrane of enterocytes

Question 19

where is saliva produced?

Answer 19

parotid, submandibular and sublingual salivary glands

Question 20

what is the function of saliva?

Answer 20

-moistens food
-starts the digestion of carbs
-starts the digestion of lipids

Question 21

where is the start of protein digestion?

Answer 21

the stomach

Question 22

how does the stomach degrade food?

Answer 22

parietal cells-hydrochloric acid secretion which denatures proteins and activates pepsin (conversion of pepsin to active endopeptidase)

Question 23

what are zymogens?

Answer 23

-inactive forms of compounds
-many enzymes are synthesised as inactive precursors that are subsequently activated by cleavage of one or a few peptide bonds. the inactive precursor is called zymogen

Question 24

what are the 2 functions of the pancreas?

Answer 24

exocrine- pancreatic juice (enzymes) and alkali secretions
endocrine- secretion of insulin and glucagon

Question 25

what are released as active forms?

Answer 25

non proteolytic enzymes -amylase -lipase -ribonuclease -deoxyribonuclease

Question 26

what are released as zymogens?

Answer 26

proteolytic enzyme -trypsin -chymotrypsin -carboxypeptidase -elastase -phospholipase

Question 27

what is the liver?

Answer 27

-production of bile -stored in gallbladder and released into the duodenum after a meal -emulsification of fat particles -aids absorption of fats by forming complexes called micelles

Question 28

bile salts?

Answer 28

synthesised from cholesterol and are transported into chalice acid and chenyeoxycholic acid which is then conjugated to amino acid (glycine or taurine)

Question 29

what is the functions of bile?

Answer 29

-emulsification of lipid aggregates -solubisation and transport of lipids in aqueous environment

Question 30

functions of duodenum?

Answer 30

-mixing secretions from pancreas, liver and duodenum with food -neutralisation of acid -further digestion -absorption

Question 31

functions of jejunum?

Answer 31

-completing breakdown -nutrient absorption

Question 32

function of lleum?

Answer 32

nutrient absorption

Question 33

what is enterokinase?

Answer 33

produced in the duodenum -is a protease -activates trypsin which activates other molecules and is a key digestive enzyme

Question 34

what enzymes make up the brush border?

Answer 34

-integral part of the membrane (not free in lumen, tethered to plasma membrane) -peptidase -lactase -sucrase -maltase

Question 35

mastication?

Answer 35

breaks up food and moistens it in the mouth

Question 36

what happens in the mouth?

Answer 36

carbs - starch broken down by amylase and maltotrise maltose and limit dextrin proteins - nothing lipids - lingual lipase present but minor contribution

Question 37

what happens in the stomach?

Answer 37

-highly acidic gastric juice is mixed with food and churned (chyme) carbs - nothing proteins - HCl denatures proteins and activates pepsin 9endopeptidase that cleaves to smaller peptides) lipids - gastric lipase present but minor contribution

Question 38

what happens in the duodenum?

Answer 38

chyme mixes with pancreatic juice and bile slightly alkaline cabs- amylase further digests starch brush border disaccharides result in monosaccharides proteins - cleaved by trypsin, chymotrypsin, elastase to produce increasingly smaller peptides, brush border peptidases produce dipeptides/amino acids lipids - pancreatic lipase digests lipids to monoglycerides and fatty acids. phospholipase digests phospholipids to lysolecithin and fatty acids

Question 39

what is passive absorption?

Answer 39

molecules move along conc gradient, very slow, no energy required

Question 40

what is facilitated transport?

Answer 40

slightly faster -involves membrane carrier is controllable

Question 41

what is active transport?

Answer 41

-uses energy -fast -uses membrane carrier -controller

Question 42

What do calcium; magnesium and phosphorous do?

Answer 42

Harden teeth and bones

Question 43

What does iron do?

Answer 43

Plays a crucial pert in haemoglobin

Question 44

What does potassium, sodium and chlorine do?

Answer 44

Helps maintain body’s pH balance and used in action potentials

Question 45

What are the essential fatty acids ?

Answer 45

Omega 6 and 3 fatty acids

Question 46

which digestive enzyme starts the digestion of carbs?

Answer 46

alpha-amylase

Question 47

what is tyripsin?

Answer 47

goes onto activate all the other proteolytic zymogens that were produced from the pancreas.

Question 48

what activates tyripsin?

Answer 48

enterokinase

Question 49

what are the products of maltose?

Answer 49

glucose and glucose

Question 50

what are the products of sucrose?

Answer 50

glucose and fructose