Topic 1: Lifestyle, Health and Risk Part 2

Question 1

what is Spearman’s rank and when is it used

Answer 1

a statistical test that looks at 2 data sets from the same sample
tells you if there’s a statistically significant correlation between them
always between -1 and 1

N = no. of individuals in sample
D = difference in rank of two measurements
theta = the sum of

Question 2

what does an alternate hypothesis state

Answer 2

it states that there is a statistically significant correlation in your data

Question 3

at what spearman’s rank value do you reject the null hypothesis and accept the alternate hypothesis

Answer 3

is the spearman’s rank is above the critical value

Question 4

what is a cohort study

Answer 4

a longitudinal study where a participants are followed over time to see who develops a disease, people’s exposure to suspected risk factors are recorded during the study, to identify possible correlation

Question 5

evaluate cohort studies

Answer 5

• studies can be very long and expensive
• invasive on the lives of patients

+ rare exposure; you can select specific conditions
+ it is the gold standard used for studying the association between a risk factor and the outcome

Question 6

what is a case-control study

Answer 6

when a group of people with a specific disease is compared to a group without it

Question 7

evaluate case-control studies

Answer 7

• they can be more prone to recall bias
• less adept at showing a causal relationship

+ they’re less time consuming and costly; useful when it’s difficult or expensive to obtain exposure data
+ useful when studying dynamic populations where follow-up can be difficult

Question 8

what is recall bias

Answer 8

when the results of a study are skewed due to the participant’s memory

Question 9

what are monosaccharides + examples

Answer 9

individual sugar monomers that carbohydrates are made from; general formula (CH2O)n

need to know = glucose, galactose, fructose

Question 10

how do disaccharides form?

Answer 10

two monosaccharides react in a condensation reaction between two hydroxyl groups on a carbon 1 and carbon 4

forms: a disaccharide, water and a 1-4 glycosidic bond

Question 11

what is hydrolysis

Answer 11

the breaking down of a a larger molecule through the addition of water

Question 12

list 3 examples of disaccharides

Answer 12

sucrose = a glucose + fructose
the form that transports sugar around plants

maltose = a glucose + a glucose
produced when starch is broken down by amylase

lactose = ß galactose + glucose
the sugar found in milk

they are water soluble, but not as soluble as monosaccharides

Question 13

how is a disaccharide converted into two monosaccharides?

Answer 13

a hydrolysis reaction

Question 14

what is a polysaccharide

Answer 14

a saccharide formed from many monosaccharides linked by glycosidic bonds

Question 15

what is starch

Answer 15

it is a storage molecule in plants
made from polysaccharides amylose and amylopectin

insoluble in water, so has no osmotic effect aka prevents cells from swelling up

Question 16

what is amylose and what is it’s structure

Answer 16

a polysaccharide that forms starch
made of alpha glucose
1-4 glycosidic bonds
spiral/helical structure - very compact, a lot can be stored in a small place

Question 17

what is amylopectin

Answer 17

a polysaccharide that forms starch
made of alpha glucose
1-4 and 1-6 glycosidic bonds
branched structure provides many terminal glucose molecules that can be rapidy hydrolysed for use during cellular respiration

Question 18

what is glycogen (saccharides)

Answer 18

a polysaccharide
insoluble in water, it doesn’t cause cells to swell by osmosis
made of alpha glucose
compact so more glucose can be stored
physically large - cant diffuse through membranes§
has 1-4 and 1-6 glycosidic bonds; the branched structure makes hydrolysis easier (has even more branches than amylopectin)

Question 19

what is cellulose

Answer 19

a polysaccharide
it is made from alternately inverted ß-glucose units
condensation reactions form 1,4-glycosidic bonds between glucoses
it forms perfectly straight chains
cellulose chains form H bond between each other
many cellulose molecules makes a microfibril
as it’s fibrous, cellulose is structurally important in plant cell walls

Question 20

function of monosaccharides

Answer 20

function - to store energy within covalent bonds, breaking these bonds during respiration is how energy is released
also used as building blocks for polymers

they are water soluble for easy transport

Question 21

lipid characteristics

Answer 21

they contain C,H,O - lower oxygen proportion than in carbohydrates

non- polar, insoluble in water but soluble in organic solvents

don’t form polymers

Question 22

what are triglycerides

Answer 22

a type of lipid that make up most of the fat in humans and animals; made of 3 fatty acid chains and a glycerol backbone

the monomers are fatty acids and glycerol

Question 23

how can fatty acids vary

Answer 23

1. length of the hydrocarbon chain
2. can be saturated or unstarurated

Question 24

describe the formation of a triglyceride

Answer 24

they are formed through a condensation reaction
each OH group on the glycerol forms an ester bond with each COOH group on the fatty acid (glycerol’s H and the acid’s OH react)
3 water molecules are released because one glycerol and 3 fatty acids are used

Question 25

what are the 2 main obesity indicators and how are they calculated

Answer 25

BMI: weight (kg)/height^2(m^2)

waist to hip ratio: waist circumference/hip circumference
- use the same units for both measurements

Question 26

why do we have to use both BMI and WHR as obesity indicators?

Answer 26

BMI considers height but doesn’t differentiate between muscle or fat and doesn’t consider fat distribution

WHR may not work around excessively obese as after a certain point fat won’t be primarily around your waist, it is distributed around the whole body

Question 27

what does a high WHR mean

Answer 27

a high WHR means more fat is around organs, this is visceral fat that increased CVD risk

Question 28

what is an ‘energy budget’

Answer 28

energy taken in by an organism - energy used up by an organism

Question 29

characteristics of glucose

Answer 29

• it’s a monosaccharide with 6 carbon atoms
• it’s structure makes it soluble so it can be transported easily
• it’s chemical bonds contain lots of energy as it is the main energy source for both animals and plants

Question 30

describe the fatty acids of a triglyceride

Answer 30

it is a hydrocarbon chain that can vary in length (the glycerol doesn’t vary)

they are hydrophobic, making lipids insoluble in water

Question 31

what do HDL’s do

Answer 31

mainly protein
transport cholesterol from body tissues -> liver, where it’s excreted or recycled
they reduce total blood cholesterol when the level gets too high

Question 32

what are LDLs

Answer 32

mainly lipid
transport cholesterol from the liver to the blood where it will circulate until cells need it
they increase total blood cholesterol when the level gets too low

Question 33

devise an experiment to test for the amount of vitamin C in food

Answer 33

1. make up Vitamin C solutions; 0, 0.2, 0.4, 0.6, 0.8, 1.0 mol
2. use a measuring cylinder to measure out 1cm3 of 1% DCPIP into a test tube
3. add one of the solutions to the DCPIP drop by drop, using a graduated pipette
4. shake for a set length of time after adding each Vit C drop (use a stopwatch)
5. record the volume of vitamin C added when the solution turns colourless
6. repeat a total of 3 times for each solution and find the mean
7. draw a calibration curve as a line of best fit on a graph using these results

you can then use the curve to test an unkown solution; find the DCPIP volume needed to decolourise then read across and down to find the concentartion

Question 34

what types of triglycerides form what types of lipoproteins

Answer 34

saturated triglyceride -> LDL
unsaturated triglyceride -> HDL

Question 35

why are terminal glucose molecules good

Answer 35

rapid hydrolysis

Question 36

where can DNA be found in a cell

Answer 36

the nucleus and mitochondria

Question 37

where can RNA be found in a cell

Answer 37

the cytoplasm, nucleus and ribosome