Nutrient digestion and absorption

Question 1

what are the principle dietary constituents

Answer 1

Carbohydrate
Protein
Fat
Vitamins
Minerals
Water

Question 2

monosaccaride

Answer 2

Monosaccharides are the simplest carbohydrates; most of them are sugars - fructose, galactose, glucose

Question 3

disaccaride

Answer 3

sugar formed when two monosaccharides (simple sugars) are joined by glycosidic bond - sucrose, lactose, and maltose.

Question 4

Oligosaccharides

Answer 4

Oligosaccharides are a type of carbohydrate chain made up of three to 10 simple sugars, which are also known as monosaccharides - glucose, fructose

Question 5

polysaccaride

Answer 5

They are long chains of carbohydrate molecules, composed of several smaller monosaccharides.

10 or more monosaccarides

Question 6

aldoses

Answer 6

An aldose is a monosaccharide (a simple sugar) with a carbon backbone chain with a carbonyl group on the endmost carbon atom, making it an aldehyde

Question 7

ketoses

Answer 7

if a monosaccharide has a ketone group on one of the inner atoms of the carbon chain it is classified as a ketose.

Question 8

glucose and galactose ketone or aldehyde

Answer 8

aldoses

Question 9

fructose ketone or aldehyde

Answer 9

ketone

Question 10

B-hydroxyl group

Answer 10

when the hydroxyl group is above the anomeric carbon

Question 11

A-hydroxyl group

Answer 11

when the hydroxyl group is below the anomeric cabon

Question 12

monosaccarides examples
what do they result from

Answer 12

Hexose sugars (6C) - glucose, galactose, fructose

Breakdown products of complex CHOs which are absorbed by small intestine

Question 13

disaccarides examples
what are they and what do they result from

Answer 13

Two monosaccharides linked together by glycosidic bond

Broken down to constituent monomers by brush border enzymes in small intestine

Lactose = glucose + galactose (lactase)
Sucrose = glucose + fructose (sucrase)
Maltose = glucose + glucose (maltase)

Question 14

what type of bond does starch contain

Answer 14

D-glucose units are connected with α-glycosidic bonds in starch

Question 15

what type of bond does cellulose contain

Answer 15

D-glucose units are connected with β-glycosidic bonds in cellulose

Question 16

what is Starch

Answer 16

plant storage form of glucose

Question 17

what makes up starch polysaccharides

Answer 17

α-amylose: glucose linked in straight chains
amylopectin: glucose chains highly branched

Glucose monomers linked by α-1,4 glycosidic bonds - hydrolysed by amylases (saliva, pancreas)

Question 18

what are α-1,4 glycosidic bonds hydrolysed by

Answer 18

amylases in saliva and pancreas

Question 19

what is cellulose

Answer 19

constituent of plant cell walls

Question 20

what makes up cellulose

Answer 20

Unbranched, linear chains of glucose monomers linked by β-1,4 glycosidic bonds

Dietary fibre (no enzymatic digestion in vertebrates - require bacteria (cellulase))

Question 21

what is glycogen

Answer 21

animal storage form of glucose

Glucose monomers linked by α-1,4 glycosidic bonds

Question 22

(cellulose)
B-1,4 glycosidic bonds

what happens when digested by A-amylase

Answer 22

results in A-1,4 glycosidic bonds
(starch, glycogen)

Question 23

what happends when starch and glycogen are broken down by amylase

Answer 23

disaccharides - maltose, sucrose, lactose produced

Question 24

what is the normal digestion of lactose

Answer 24

lactase breaks down lactose into glucose and galactose

Question 25

if someone is lactose intolerent what happens to lactose

Answer 25

there is no lactase so bacteria ferments and acids and gases are produced causing irritation

Question 26

maltose components

Answer 26

glucose and glucose

Question 27

sucrose components

Answer 27

glucose and fructose

Question 28

lactose components

Answer 28

galactose and glucose

Question 29

what breaks down maltose

Answer 29

maltase into 2 glucose

Question 30

what breaks down sucrose

Answer 30

sucrase into 1glucose and 1 fructose

Question 31

basolateral membrane

Answer 31

membrane facing away from the lumen, faces blood vessels of small intestine

Question 32

apical membrane

Answer 32

brush border bristles (microvilli), increasing surface area, faces lumen

tight junction complex

Question 33

proteins

Answer 33

Polymers of amino acids linked together by peptide bonds

Question 34

what is often undergone by proteins

Answer 34

post-translational modification (eg addition of CHO = glycoprotein; lipid = lipoprotein)

Question 35

what are enzymes which hydrolyse peptide bonds and reduce proteins or peptides to amino acids called

Answer 35

proteases, peptidases