Alan Boyd

Question 1

What are macronutrients?

Answer 1

They are sources of energy

Question 2

How much energy can carbohydrate and protein provide?

Answer 2

approximately 4 kcal per kg

Question 3

How much energy can fat provide?

Answer 3

approx 9 kcal per kg (more energy dense)

Question 4

What does C18:1 Δ9 denote?

Answer 4

it denotes an 18 carbon molecule with a single double bond at the 9 position

Question 5

Below their melting point, how are triacylglycerols stabilised in solid form?

Answer 5

they are stabilised by van der Waals interactions between the acyl chains

Question 6

The presence of unsaturated fatty acids in a triacylglycerol reduces the degree of molecular packing that is possible in the solid form so that………………. energy is required for melting

Answer 6

less

Question 7

How can oils be converted into fats?

Answer 7

by adding a hydrogen across double bonds in the acyl chains. This process is called hydrogenation and requires a nickel catalyst.

Question 8

In what configuration do you find the double bonds in naturally occurring unsaturated fatty acids?

Answer 8

cis configuration

Question 9

Ture/False: in industrial hydrogenation, it is possible for trans double bonds to occur.

Answer 9

true

Question 10

The consumption for trans fatty acids leads to an increased risk of…..

Answer 10

cardiovascular disease

Question 11

Which country introduced a complete ban of trans fatty acids in 2003?

Answer 11

Denmark

Question 12

What is the most expensive single class of drugs that are prescribed in the UK?

Answer 12

lipid regulating drugs, predominantly statins

Question 13

Cholesterol is a precursor for biosynthesis of

Answer 13

steroid hormones

Question 14

What do statins do?

Answer 14

reduce endogenous biosynthesis

Question 15

Other than statins, what other approach is used to treat high cholesterol levels?

Answer 15

the use of a nutriceutical (plant stanol esters)

Question 16

Other than statins, what other approach is used to treat high cholesterol levels?

Answer 16

the use of a nutriceutical (plant stanol esters) which are the active ingredient in the Benecol range of foods

Question 17

Where does most digestion and all absorption of nutrients take place in?

Answer 17

the small intestine

Question 18

What are enterocytes?

Answer 18

the predominant cells in the small intestinal mucosa (epithelial cells)

Question 19

Enterocytes are linked together by what kind of junction?

Answer 19

tight

Question 20

In order to get from the gut lumen into the bloodstream, what do nutrients need to do to pass through the enterocytes?

Answer 20

They get taken up at the apical surface and leave through the basolateral surface

Question 21

Enzymes such as sucrases are often referred to as …………….. and include many digestive peptidases and …………………

Answer 21

brush-border enzymes; glycosidases

Question 22

Monoacylglycerols and fatty acids are able to diffuse through the lipid bilayer of the apical membrane and once inside the enterocyte they are?

Answer 22

reconverted into triacylglycerols and packaged into lipoproteins called chylomicrons.

Question 23

Chylomicrons are released into…

Answer 23

the lymph from where they eventually pass into the bloodstream

Question 24

Cholesterol binds to which transporter which explains how plant stanols are able to block uptake of dietary cholesterol?

Answer 24

NPC1L1

Question 25

How is the stanol concentration in the gut maintained?

Answer 25

plant stanols has a specific transporter to pump the stanols back across the apical membrane.

Question 26

How was the role of the specific cholesterol transporter discovered?

Answer 26

was discovered as a result of a compound called ezetimibe which was intially found to lowernserum cholesterol without any effect upon endogenous synthesis.

Question 27

Give examples of macronutrients

Answer 27

carbohydrates, fats, proteins

Question 28

Give examples of micronutrients

Answer 28

vitamins, essential fatty acids, minerals

Question 29

If starch is branched, what is it called?

Answer 29

amylose

Question 30

If starch is unbranched, what is it called?

Answer 30

amylopectin

Question 31

Glycogen resembles amylopectin but is it more or less branched?

Answer 31

more branched

Question 32

What is cellulose?

Answer 32

the primary constituent of plant cell walls, consists of glucose in long, unbranched chains in which the glucose monomers are linked by β-1,4 linkages

Question 33

What are hemicelluloses?

Answer 33

These are the main constituent of cereal fibres and are branched structures composed of pentoses and hexoses and the uronic acids. Hemicelluloses may be soluble or insoluble.

Question 34

What are pectins?

Answer 34

These are insoluble complex polysaccharides

Question 35

What are Gums?

Answer 35

these are soluble complex polysaccharides

Question 36

What are lignins?

Answer 36

these are non-polysaccahride woody polymers of aromatic alcohols.

Question 37

How many amino acids does myoglobin have?

Answer 37

153

Question 38

Is there a β structure in myoglobin?

Answer 38

no

Question 39

In myoglobin, how many helices are there and how are they 'numbered'?

Answer 39

8, 'numbered' A-H

Question 40

What is Haem?

Answer 40

a tetrapyrrole ring structure (a porphyrin ring) with a central iron atom in the Fe(II) state.

Question 41

In haem, how many ligands can bind to the iron atom?

Answer 41

6

Question 42

Myoglobin exhibits a simple saturation curve for oxygen binding. This type of curve is referred to as a:

Answer 42

rectangular hyperbola

Question 43

The K(D[subscript]) of myoglobin for O2 is

Answer 43

2-3 mm Hg

Question 44

What is the difference between myoglobin and haemoglobin?

Answer 44

Myoglobin is an iron- and oxygen-binding protein found in the muscle tissue of vertebrates in general and in almost all mammals. It is related to hemoglobin, which is the iron- and oxygen-binding protein in blood, specifically in the red blood cells.

Question 45

What is the Adair equation?

Answer 45

it models the behaviour of a tetrameric binding protein exhibiting cooperative behaviour in terms of four sequential binding reactions.