topic 1 - lifestyle and risk Flashcards
explain a water molecule…
including charges, bonding when two H2o’s attach and what this bonding does
hydrogen atoms = partially positive
oxygen atoms = partially negative
- this separation of charge is called a DIPOLE
- polar molecule as one end is negative and the other is positive
- hydrogen bonding
- H bonding creates cohesion and adhesion, enabling effective transportation
explain why water is a good solvent. what does it dissolve in?
- chemicals dissolve easily in water due to dipole nature
- ionic substances dissolve easily. negative ions attracted to positive end of H20 and positive ions attracted to negative ends of H20. ions become surrounded by water molecule and dissolve
- polar molecules dissolve easily. polar groups become surrounded as they are hydrophilic
- this allows chemical reactions to occur within cells as the dissolved solutes are more chemically reactive when they are free to move about
- hydrophobic substances dont dissolve.
explain waters thermal properties and why this is useful in organisms
- specific heat capacity is very high
- because lots of energy needed to break H bonds
- large input of energy also increases temp a little
- useful in organisms as helps to avoid rapid changes
why have a heart and circulation? what are the differences in circulatory system between uni and multicellular organisms?
to move substances around the body.
unicellular:
- use diffusion as only short distance
multi:
- as size increases SA to V ratio decreases
- diffusion insufficient so mass transport used
- MT is used to carry raw materials from specialised organs to the body cells and to remove metabolic waste.
name four features of a mass transport system
- network to move through
- medium for movement
- controlled direction
- maintenance of speed
arteries
- function and adaptations
- carry oxygenated blood away from the heart to body
- small lumen to maintain high blood pressure
- smooth endothelium so less resistance
- endothelium folded to allow artery to expand
-lots of collagen fibres for strength and support - thick walled to cope with high pressure
veins
function and adaptations
- carry deoxygenated blood back to heart
- large lumen to reduce resistance to flow
- wider with little elastic tissue as lower pressure
- valves to prevent backflow
explain the three stages of the cardiac cycle
- atrial systole: atria contracts increasing pressure of chambers and decreasing volume. valves open and blood flows to ventricles
- ventricular systole: ventricles contract forcing atrioventricular valves to close, semi lunar to open. blood leaves the left ventricle via aorta and right via pulmonary artery
- cardiac diastole: atria and ventricles relax. pressure decreases and SL valve closes. blood returns to heart and atria fills.
atherosclerosis
- define.
- explain how it happens
- the hardening of arteries caused by building up of fibrous plaque
- endothelium becomes damaged. this could happen via smoking, high BP etc
- inflammatory response. white blood cells move into artery.
- over time, white blood cells, cholesterol, calcium salts and fibres build up leading to plaque.
- artery wall loses its elasticity
- plaque build up restricts blood flow
how do blood clots form
- endothelium damage exposes collagen fibres
- platelets attach to exposed collagen fibres
- platelets release thromboplastin protein
- thromboplastin activates an enzyme that catalyses prothrombin to thrombin. in order for this to occur, calcium ions and vit k must be present
- thrombin catalyses conversion of soluble fibrinogen into fibrin
- mesh of fibrin traps platelets and red blood cells and clot forms
what are the consequences of blood clots
- angina: narrowing of coronary arteries limits amount of oxygen rich blood reaching heart
- heart attack: plaque in coronary arteries. heart muscle does not receive blood.
- stroke
- deep vein thrombosis
seven factors that increase risk of CVD
- diet - sat fat increases plaque build up. high salt increases bp
- high bp - increases damage to artery walls which increases atheroma formation
3, smoking -
- carbon monoxide binds with haemoglobin and reduces amount of oxygen carried
- nicotine makes platelets sticky and narrows arteries
- decreases amount of antioxidents in blood - inactivity
- genetics
- age: arteries become less elastic
- gender: oestrogen makes arteries more elastic
explain LDL and HDL
LDL: mainly lipid, transport cholesterol from liver to blood. increases blood cholesterol
HDL: mainly protein, transports cholesterol from body tissues to liver. deceases blood cholesterol
antihypertensives
- function
-examples
- benefits and risks
- reduce blood pressure
- beta blockers (prevent increases in heart rate), and vasodilators (widen vessels), and diuretics (reduce water absorption)
- can be given in combination. bp monitored at home
- palpatations. fainting
statins
-function
-risks
- reduce amount of LDL cholesterol
- nausea, inflammation
anticoagulants
- function
- example
- benefits
-risks
- reduce formation of blood clots
- eg warfarin
- can be used with people who have CVD already
- excessive bleeding. can damage foetuses
platelet inhibitors
-function
-benefits
-risks
- make platelets less sticky reducing atheromas
- can be used with people who have CVD already
- excessive bleeding, stomach bleeding
carbohydrates general formula
Cn(H20)n
three main monosaccharides
- glucose
- galactose
- fructose
what is sucrose made from and what is bond
- alpha glucose and fructose
-1,2 glycosidic
what is maltose made of and bond
- alpha and alpha
- 1,4 glycosidic
what is lactose made of and bond
- galactose and glucose
- 1,4 glycosidic
starch
- what is it
- made of?
- soluble?
- main energy storage in plants
amylose: straight chain of glucose molecules. spiral shape. 1,4 bonds. compact.
amylopectin: 1,4 and 1.6 bonds. side branches allow enzymes to break down glucose easily. - insoluble. compact structure and insolubility makes it good at storage
cellulose
- made of?
- monomer
- properties
10,000 glucose molecules
forms straight chain
no branches
hydrogen bonds
end up with microfibrils
monomer= beta glucose
bond= 1,4
strong and insoluble. only found in plant cell walls
glycogen
- used for
- structure
-properties
animals store excess glucose as glycogen
- 1,4 and 1,6 with side branches so can be released quickly
- compact and large, good for storage
- insoluble
- alpha glucose
saturated fats
- long and straight
- no double bonds
- strong IMB so solid at room temp
unsaturated fats
- double bond forms kink in chain which prevents molecules packing close together
- thus IMF are weak so liquid at room temp
- made solid by adding hydrogen
lipid properties
- fatty acid tail is hydrophobic so insoluble
- very compact
- non polar and insoluble = good for storage
- provide thermal insulation as conduct heat slowly
what will happen to additional energy if a person takes in more than required
it will be stored as fat in body cells
causal relationship definition
a change in one variable directly results in the change of another
why does the structure of glycogen allow it to be an energy store
- polymer of glucose
- branched for rapid hydrolysis
- compact to allow large amount of energy stored in small place
- insoluble therefore does not affect osmosis
a platelet is….
a cell fragment that releases thromboplastin
fibrinogen is…
a soluble plasma protein
how does a blood clot lead to stroke/heart attack etc
- reduced blood flow so less oxygen rich blood
- less aerobic respiration so less ATP produced
- lactic acid produced from anaerobic respiration
- lactic acid is toxic
capillaries
- adaptations
- one cell thick which reduces diffusion distance for oxygen and carbon dioxide between blood and tissues
- pores which allow blood plasma to leak out and form tissue fluid. white blood cells can also combat infection by squeezing out from the pores
- narrow lumen providing more time for diffusion to occur
- no collagen
- thin permeable walls, allowing substances to leave the blood to reach body tissues
what is the vessel transporting blood at highest pressure
aorta
which chamber of the heart has the highest pressure
left ventricle
name one function of glycoproteins in cell membrane
cell recognition
why is ATP required for facilitated diffusion
- being moved against a conc gradient using active transport
how does change in primary structure affect enzyme
different primary structure results in different sequence of amino acids
change in R group changes
substrate cannot bind
stopping…..
Compare diffusion and active transport
Similarities
both move molecules through the {phospholipid bilayer / cell surface membrane} (1)
(in both) molecules can move through proteins (1)
Differences
diffusion occurs down a concentration gradient whereas active transport occurs against a concentration gradient (1)
diffusion is {passive / does not require ATP} whereas active transport requires ATP (1)
Why is water an ideal transport medium
water is a solvent (1)
because water molecules surround { polar molecules / ions } / hydrogen bonds form between water molecules and solute molecules (1)
water is liquid so has the ability to flow (1)
Which side of the heart has lower pressure
The right as blood is transported from heart to lungs
DNA consists of mononucleotides joined together by bonds between….
deoxyribose and a phosphate group
Experiment to investigate heart rate of Daphnia
- Make up at least five different caffeine solutions of diff concentration and a control solution
- Transfer one daphnia onto cavity slide
- Using pipette place five drops onto daphnia. Wait five minutes so it absorbs
- Place under microscope and adjust focus
- Count heart beats in twenty seconds
- Repeat ten times using same conc but different daphnia
7.repeat using other concs
Controls : temperature, volume of caffeine solution.
Experiment to investigate vitamin c content
- Transfer 1cm of DCPIP solution into a test tube with a pipette.
- Add Vitamin C solution dropwise to the DCPIP solution. Shake after each drop.
- Record the volume of Vitamin C that is required to change the colour of the
DCPIP. - Repeat the experiment (to get concordant results) and replace the Vitamin C solution with the fruit juices
- Use a calibration curve to determine vit c content
REMEMBER IN EXPERIMENTS
Controls and at least five samples
Investigating membrane permeability
- Cut beetroot into 8 identical cylinders using a cork borer and wipe/rinse to clean off any pigment released as a result.
- Place each of the cylinders of beetroot in 10 ml of distilled water. Place each test tube in a water bath at a range of temperatures between 0 and 70°C.
- Leave the samples for 15 minutes- pigment will leak out of the beetroot.
- Record the exact temperature of the water bath using the thermometer.
- Remove the test tubes from the water baths and remove the cylinders of beetroot
from them. Decant the liquid into clean test tubes. - Set the colorimeter to a blue filter and zero using a cuvette with distilled water.
Filter each sample into a cuvette using filter paper - Measure the absorbance for each solution. A higher absorbance indicates higher pigment concentration, and hence a more permeable membrane
Membrane permeability experiment conclusions
As the temperature increases, the permeability of the cell-surface membrane also increases. This is because the proteins in the membrane denature as the heat damages the bonds in their tertiary structure. This creates gaps in the membrane so it is easier for molecules to pass through it.
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● At low temperatures, phospholipids have little energy and are packed closely together to make the membrane rigid. This causes a decrease in permeability and restricts molecules from crossing the membrane.
How can membrane permeability experiment be adapted for ethanol
The method can be modified to investigate the effect of ethanol on membrane permeability by having concentration of ethanol as the independent variable. Ethanol causes the cell-surface membrane to rupture, releasing the betalain pigment from the cell. Higher concentrations of ethanol will cause more disruption to the membrane and more gaps will form, thus as concentration of ethanol increases, so does the permeability of the cell-surface membrane.
compare and contrast structure of cellulose and amylopectin
Similarities:
both are {polysaccharides / polymers of
glucose} (1)
both contain (1,4) glycosidic bonds (1)
Differences:
cellulose contains { /beta } glucose
whereas amylopectin contains { / alpha }
glucose (1)
cellulose { is not branched / does not contain
1-6 glycosidic bonds } (1)
magnification formula
image/actual
both must be in micrometres - so if in mm times by 1000
Compare and contrast the molecular structures of globular and fibrous proteins.
both are chains of amino acids joined by peptide bonds
(1)
both contain named bonds (holding molecule in its three
dimensional shape) (1)
globular proteins have hydrophilic groups on the outside
whereas fibrous proteins have hydrophobic groups on
the outside (1)
globular have tertiary or quaternary structures whereas
fibrous have little or no tertiary structure (1)
globular are folded into compact shapes whereas fibrous
have long chains (1)
adaptations of a mammalian lung
many alveoli provide a large surface area (1)
{alveoli / capillaries} have walls that are one cell thick
providing a short distance for diffusion (1)
high concentration gradient maintained by {circulation /
ventilation} (1)
extensive capillary network around alveoli provides large
surface area for gas exchange (1)
why is water a good solvent
- polar so can surround molecules and dissolve them
Describe how nucleotides join together to form DNA
condensation reaction (1)
phosphodiester bonds (1)
bonds form between phosphate and deoxyribose
how are arteries adapted to withstand high pressure
(more) collagen provides strength (to withstand pressure) (1)
(contraction of) muscle allows constriction (of lumen / artery)
(1)
elastic fibres allow (stretch and) {recoil / lumen to return to
original size} (1)
Explain why high levels of sugars in a person’s diet could lead to obesity
energy intake higher than energy output (1)
• (excess) {energy / sugars} can be {stored as / converted to} fat
(1)
• leading to weight gain (greater than overweight) (1)
• obesity as indicated by a {BMI above 30 / waist-hip ratio
greater than 0.85 in women or 1.0 for men} (1)
what do mass transport systems help to do
- bring substances quickly from one exchange site to another
- maintain diffusion gradients at exchange sites
- ensure effective cell activity by supplying reactants and removing waste products
difference between a closed and open circulatory system
closed = blood is pumped around the body and is contained within a network of blood vessels
open = the blood is inside the body cavity and bathes the organs
difference between a double and single circulatory system
double = two loops, one to the lungs and one to the body
single = one loop that includes the lungs and the body
how is the left ventricle of the heart adapted
- thicker muscle than right ventricle for strong contraction to pump blood all the way around the body
- right ventricle only had to carry blood to the lungs
explain the process of blood clotting (thrombosis)
- damaged blood vessel exposes collagen and releases a protein called thromboplastin
- Calcium ions from the plasma, along with thromboplastin, trigger the
conversion of soluble prothrombin protein into the enzyme thrombin - Thrombin catalyses the conversion of the soluble protein fibrinogen to the
insoluble protein fibrin - Fibrin fibres mesh and tangle together, trapping platelets and red blood cells
- blood clot is formed
how can perception of risk be overestimated or underestimated
Risk can be overestimated because of factors such as
- Misleading information in the media
- Overexposure to information
- Personal experience of the associated risk
- Unfamiliarity with the event
- The event causing severe harm
Risk can be underestimated because of factors such as
- Lack of information
- Misunderstanding of factors that increase the risk
- A lack of personal experience of the associated risk
- Unfamiliarity with the event
- The harm being non-immediate
what is energy budget
the amount of energy taken in by an organism minus the amount of energy the organism transfers during life processes
how can energy budget be calculated
energy input - energy output = energy budget
what are the main functions of monosaccharides
- store energy within their bonds. when bonds are broken during respiration, energy is released
- can join together to form large carbs
what is the name of the reaction when the glycosidic bond is broken
- hydrolysis reaction (water is added)
- opposite is condensation (when two monosaccharides are joined together)
what is the function of disaccharides
- to provide the body with a quick release source of energy
how does the structure of starch allow it to be used as an energy store
- The amylose in starch has a helical structure which makes it very compact, meaning that much can be stored in a small space
- The amylopectin in starch has branches that provide many terminal glucose molecules that can be easily hydrolysed for use during cellular respiration or
added for storage
monomers of triglycerides
3 fatty acids and one glycerol
bond in triglycerides
ester
why do multicellular organisms need a circulatory system whereas uni cellular do not (2 marks)
- multicellular organisms are made of many layers of cells
- diffusion distance to cells deep in the body would be too great
mass transport system definition
the bulk movement of gases or liquids in one direction, usually via a system of tubes
using a named example, explain the benefits of the circulatory system as a mass transport system
- the lungs are the circulatory system
benefits
1. brings oxygen quickly from the lungs to the cells for respiration
2. removes co2 quickly to the lungs
3. maintains diffusion gradient at the alveoli
4. cells can carry out respiration continuously as they receive a constant supply of oxygen
explain blood pressure in…
the arteries and arterioles
the capillaries
the venules and veins
arterioles and artery:
pressure is higher as contractions of the heart force the blood into the arteries at high pressure
pressure remains high as narrow lumen maintains high blood pressure
pressure fluctuates as pressure increases when the heart contracts and decreases when the heart relaxes
capillaries:
pressure in capillaries decrease as the capillaries are very narrow
veins and venules:
bp is low as there is a greater distance between the veins and the heart
bp shows no fluctuation as the contractions of the heart no longer affect blood pressure in the veins
explain the role of hydrogen bonding and its importance in transporting water
allows water molecules to stick together
h bonds form between other molecules and water
explain the dipolar nature of water molecules
- covalent bonding occurs between an oxygen atom and two hydrogen atoms
- electrons are shared unequally between an oxygen and hydrogen atom
- oxygen has a greater electronegative charge therefore oxygen attracts electrons towards its nucleus
using a names example, explain how valves work
valves prevent the backflow of blood
eg the right av valve prevents blood from returning to the right atrium from the right ventricle
name which part of the heart causes the increase in pressure in the aorta
explain why this increase is important for organisms
- the left ventricle
- ensures that the blood leaving the heart is under high pressure
- meaning that oxygenated blood reaches all the body
- ensuring that oxygen is delivered to the cells for aerobic respiration
discuss the ethical issues when using organisms such as daphnia
- organisms cannot give consent to be part of experimental procedures
- organisms cannot communicate when they feel pain
name two precautions that should be taken when using live organisms in experiments
- ensure no harm comes to the organisms
- keep experimental period as short as possible
why are lipids classed as more energy rich storage compounds than carbohydrates
lipids contain a lower proportion of oxygen than carbohydrates
describe the role of the ester bond and how they are formed
- to link a fatty acid and glycerol
- formed by esterification resulting in a water molecule as a by product
compare the structures of saturated and unsaturated fatty acids
- both have hydrocarbon tails
- both have a carboxylic acid group at one end
- unsaturated has carbon to carbon double bonds
- Unsaturated can have kinked chains
how can the misuse of alcohol result in an increased risk of CVD
- can increase heart rate
- increasing risk of atheroma formation
how does a diuretic reduce blood pressure
- more urine means more water leaves the body
- reducing blood pressure
- which reduces blood pressure in the blood vessels
compare and contrast the structure of a and b glucose
- both contain 6 carbon atoms
- both have a ring structure
- Alpha glucose has the H above carbon 1 and the OH group below
Beta glucose has the H below carbon 1 and the OH group above
state two features of a glycosidic bond
- formed between two OH groups
- strong covalent bond
relate the structure of the heart’s chambers to their function
atria:
thin walled and elastic, so they can stretch when filled with blood
ventricles:
thick muscular walls pump blood under high pressure.
left ventricle is thicker than the right as it has to pump blood all the way around the body
describe the function of the hearts major blood vessels
vena cava: brings deoxygenated blood from the body to the heart
pulmonary artery: takes blood from the heart to the lungs
pulmonary vein: brings oxygenated blood from the lungs to the heart
aorta: takes blood from the heart around the body
explain why a mammal born with a hole between two ventricles will become more easily tired due to a lack of energy
- less oxygen available for aerobic respiration
- deoxygenated blood mixes with oxygenated blood
- thus reducing the concentration of oxygen in the blood circulating in the body
Explain how atherosclerosis in one part of an artery could increase the likelihood of it developing in another part of the same artery
atherosclerosis narrows the lumen
increasing blood pressure
explain why high levels of sugar in a persons diet could lead to obesity
- energy intake higher than energy output
- excess energy can be stored as fat
- leading to weight gain
how can enzymes break down polysaccharides
hydrolysis of glycosidic bonds
how do LDL’s contribute to the development of atherosclerosis
LDL carries cholesterol in the blood
cholesterol is deposited to form atheroma
in the endothelium of an artery
how does atherosclerosis damage heart muscle
- narrows lumen of coronary arteries
- which reduced oxygen flow to the cardiac muscle
- reducing aerobic respiration
explain how blood tests and obesity indicators can be used to collect data to predict the risk of developing CVD
-blood test to measure LDL and HDL cholesterol levels
- higher HDL:LDL decreases risk
- measurement of BMI and waist to hip ratio
what is
- a platelet
- thrombin
- fibrinogen
- a cell fragment that releases thromboplastin
- an enzyme that changes fibrinogen to fibrin
- a soluble plasma protein
how do amino acids join together to form a 3D structure
- peptide bonds
- between amino group and carboxyl group
- primary structure is the sequence of amino acids
- folding of primary structure held together by bonds
describe the reaction between two glucose molecules to form a disaccharide
- condensation reaction
- involving OH groups
give two reasons why varying number of people in an experiment does not affect validity
% incidence used rather than number
wide range still considered
large sample size
correlation definition
shows an association or relationship but no causal link
Explain how smoking increases the risk of developing atherosclerosis.
- nicotine stimulates adrenaline which increases blood pressure
- high blood pressure damages endothelium
- leading to inflammatory response
why do we need a heart
to pump blood and supply oxygen to body cells by mass transport
because a small surface area to volume ration does not allow diffusion to occur at a sufficient rate
hydrolysis reaction definition
- breaks bonds
- uses water
why does it improve validity if all seeds are taken from the same plant
reduced genetic variation
same age
Explain how the arrangement of cellulose microfibrils contributes to the
physical properties of plant fibres.
- tensile strength
- h bonding forms net like arrangement of microfibrils
Describe the role of microorganisms in the recycling of carbon
- decomposition by microorganisms
- respiration
- releases co2 for photosynthesis
- methane released in anaerobic conditions
- methane available as fuel
