Doctors measured the health of lungs by calculating the FEV1 : FVC ratio. FEV1 is the maximum volume of air exhaled in one second . FVC is the maximum volume of air exhaled in one breath . The minimum FEV1:FVC ratio of healthy lungs is 0.7:1.
The man’s FEV1 is 2.2 and the FVC is 3.6
Determine how many times greater the minimum ratio of healthy lungs is to his ratio
What i did wrong - I used the original ratio to determine the ratio of the man’s lungs
What to do instead - 2.2 divided by 3.6 to get 0.61 this gives you the ratio of the man’s lungs . You divide because you’re working out the ratio .
Then to find the amount of times greater you divide 0.7 by 0.61 this is because you know the amount of times greater the healthy man’s lungs is compared to his lungs
Tidal volume is the volume of air inhaled and exhaled during a single breath when a person
is resting. The tidal volume in a person with emphysema is reduced compared with the tidal
volume in a healthy person.
Suggest and explain how a reduced tidal volume affects the exchange of carbon dioxide
between the blood and the alveoli.
What i did wrong - I said the right things but i didn’t go into in detail which is what the markscheme needs
1- Less carbon dioxide is exhaled out of the lung
2 - so reduced diffusion and reduced concentration gradient between blood and alveoli
3- less carbon dioxide moving out the blood
Explain the advantage of larger animals having a specialised system that facilitates oxygen uptake
What i did wrong - Always forget to mention why larger animals need a specialised system in the first place which is always a mark on the markscheme.
Correct answer - Larger organisms have a smaller surface area to volume ratio
- By having a specialised system it overcomes long diffusion pathway
Figure 1 shows two models of oxygen uptake found in animals . ( Picture shows oxygen uptake through system developed to the outside of the body e.g fish gills ) the other picture shows oxygen uptake developed on the inside of the body e.g human lungs
Suggest how the environmental conditions have resulted in adaptations of systems using model a than b
- What i did wrong i didn’t break the question down to try and understand it the question basically ask why do fish need to have gills on the outside all i had to talk about is how oxygen is low in water and explain it
the answer - 1) In A water has a lower oxygen partial pressure compared to air . 2 ) This means that through having the system on the outside it increases the surface area for gas exchange/ reduces diffusion distance
Figure 2 shows changes in concentration of oxygen in two gas exchange systems.
I - air water entering the gas exchange system
E- Air water leaving the gas exchange system
A - Arterial blood entering the gas exchange system
v - Venous blood leaving the gas exchange system
In fishes the V is higher then the E
A student studied figure 2 and concluded that the fish gas exchange system is more efficient in human gas exchange. use figure 2 to explain this conclusion
what i did wrong - I panicked so i didn’t spend enough time trying to understand the question its basically showing if the organism used up all the oxygen content if it did than it shows that they had an efficient gas exchange.
The answer
1) In fish blood leaving ( V ) has a higher concentration of oxygen compared with i (E) Whereas with humans blood leaving ( V) has less oxygen then air leaving ( E) this shows that fish had a greater proportion of oxygen then they took in
The table shows two features of two mammals . Bats are flying mammals shews are ground living mammals . Bats had a mean body mass (kg) of 0.096 and a mean lung volume (cm3) of 12.48. Shrews had a mean body mass (kg ) of 0.024 and a mean lung volume of ( 0.72)
Calculate how many times the lung volume per unit of body mass of the bat is greater than the shrew. Give your answer to an appropriate number of significant figures . Give one suggestion to explain this difference.
What i did wrong - I times the answer because i thought it was right but i spoke with chat and if they ever ask you the lung volume per body mass you always divide . Per = divide whereas if it says total or combined then you times
right answer
1) divide both the shrew and bats lung volume with their body mass so for bat 12.48 divided by 0.096 = 130 and for the shrew 0.72 divided by 0.024 = 30 .
2) then to find the amount of times greater you divide 130 by 30 which gives the answer 4.33333333
3) Round to appropriate significant figures therefore answer is 4.3
4) explanation - bats need more energy because they fly which requires energy
Two solutions often used to stain tissues are haematoxylin solution and iodine solution.
• Haematoxylin solution stains DNA a blue colour.
• Iodine solution stains starch a blue-black colour.
The scientist used haematoxylin solution and not iodine solution to stain the lung tissue.
Suggest why.
why i got this wrong - I just genuinely don’t know the answer it was pretty much in the question tho most of the time when they ask this it’s because the organism doesn’t have the thing it’s testing. if wrong just say makes nucleus visible and you will get the mark
What is the answer - This/animal/lung tissue does not contain starch;
Accept cell(s) for ‘tissue’
2. (Makes) nucleus visible;
OR
Nucleus contains DNA
d) Scientists investigated the link between the lung disease asthma and three risk factors.
They studied a large number of people. They recorded if the people had asthma and if
they:
• were obese
• burned wood indoors as a fuel
• lived in a house with a cat or dog.
The scientists used a statistical test to calculate the probability of the link between asthma
and each risk factor being due to chance.
The table below shows their results.
Risk Factor Probability (P value)
Obese < 0.001
Burned wood indoors = 0.06
Lived with a cat or dog < 0.05
A student who looked at these results concluded that all three risk factors are linked with
asthma. Evaluate this conclusion.
What i did wrong - I only got 1/3 marks because i evaluated the study more then just looking at the three risk factors . Do that first and if you have space then add more stuff just in case
What is the right answer - 1. (Link/risk with asthma and) living with cat or dog is (statistically) significant;
2. (Link with) obesity is most/highly significant;
Reject ‘results are significant’
Not supported
3. (Link/risk with asthma and) burned wood (indoors) is not (statistically) significant
Carbon monoxide is a poisonous gas that is present in cigarette smoke. This carbon monoxide
can be absorbed into the blood where it binds with haemoglobin.
Scientists investigated the concentration of carbon monoxide in cars in which people were
smoking or not smoking. They measured the concentration with the car windows open and
closed. The graph shows the scientists’ results as they presented them. A value of ± 2 standard
deviations from the mean includes over 95% of the data.
(c) In England, in October 2015, a law was introduced making it illegal to smoke in a car
carrying someone who is under the age of 18.
Following the introduction of the law, a politician stated:
‘It is dangerous to smoke when a child is in the car. Higher levels of deadly toxins can build
up, even on short journeys, and children breathe faster than adults, meaning they inhale
more of the deadly toxin.
the graph showed the first bar with no smoking with the window closed and not closed overlapping and then whilst smoking over lapping and 5 mins after smoking overlapping
what i did wrong - just didn’t link back to the question barely spoke about co concentration
what the answer is - c) For
Significantly higher concentrations of CO (compared with no smoking) with closed
window (as no overlap in 2 × SD);
Accept higher concentrations of CO with closed window are not due
to chance
Idea of higher is required, not just difference
Any increase in CO could be dangerous;
OR
CO causes less oxygen to be carried / provided (which could be deadly in children);
(significantly) higher levels after (just) 5 minutes (with closed windows supporting
short journey statement);
Idea of higher is required, not just difference
Against
4. 5. 6. No idea if (roughly) 5ppm is ‘deadly’;
No significant difference with open window (as 2 × SD overlaps);
Accept difference with open window could be due to chance
No data on child breathing rates;
OR
Idea that children breathe faster but have smaller lung volume, so overall volume of
CO inhaled could be similar
What happens when the semi lunar valve open and close .
What i did wrong - I said it the wrong way around i thought when the semi lunar valve closed it meant the pressure is higher in the ventricles then in the aorta .
Quick recap- when the valve open it means the pressure in right ventricle is higher then in aorta so blood flows form ventricle to arteries
What the right answer was - When closed the pressure in the aorta is higher than in the left ventricle to prevent backflow of blood from arteries to ventricles .
Q is an aorta and in the diagram it showed a small increase in pressure and in rate of blood flow in the aorta . Explain how this happens and the importance.
Elastic recoil (of the aorta wall/tissue);
Reject muscle contracting.
Ignore reference to muscle relaxing.
2. Smooths the blood flow
Very common question - suggest two ways the students can improve the quality of his drawing of blood vessels in this dissection .
Only use single lines/do not use sketching (lines)/ensure lines are
continuous/connected;
2. Add labels/annotations/title;
3. Add magnification/scale (bar);
4. Draw all parts to same scale/relative size;
5. Do not use shading/hatching
Describe two precautions the students should take when clearing away after dissection - Got right but very common question .
Carry/wash sharp instruments by holding handle
OR
Carry/wash sharp instruments by pointing away (from body)/down;
Accept for ‘instruments’, a suitable named example, eg. scalpel
2. Disinfect instruments/surfaces;
Accept for ‘instruments’, a suitable named example, eg. scalpel
Accept for ‘disinfect’, sanitise OR use antiseptic
3. Disinfect hands
OR
4. Wash hands with soap (and water);
Accept for ‘disinfect’, sanitise OR use antiseptic
Put organ/gloves/paper towels in a (separate) bag/bin/tray to dispose;
explain how an arteriole can reduce blood the blood flow into capillaries
- Just forgot to say muscle contracts who’s is a key mark in markscheme so cannot forget
What the right answer is - Muscle contracts which constricts lumen
What can you conclude from the appearance of the valves in the imagine above about heart muscle activity and blood movement between ventricles and arteries and atria and ventricles
( valves between ventricles and arteries and closed and valves between atria and ventricles are open )
- Ventricles relaxed no blood bacflow into ventricles ( ventricles and arteries )
- Atria muscle contracted blood moves from atria to ventricles ( from atria to ventricles )
Give to safety precautions that should be followed when dissecting a heart
Use a sharp scalpel/scissors
Wash hands/wear gloves
Disinfect bench/equipment
Cover any cuts
Cut away from self/others/on a hard surface
Safe disposal
How does atrioventricular valve maintain unidirectional flow of blood
- Pressure in (left) atrium is higher than in ventricle/B causing valve to open;
-Pressure in (left) ventricle/B is higher than in atrium causing valve to close;
caffeine effects the autonomic system . Suggest how caffeine could account for the results of group I in figure 2 at 60 minutes.
- More impulses/action potentials along sympathetic (nervous system
pathway/branch);
Ignore signals/information/ messages
Idea of more impulses/action potentials is required - To SAN increasing the heart rate
Explain why valves were put in an isotonic solution
- water potential is same inside and outside of the cell presents any loss or gain by osmosis from occurring and therefore prevents any damage to the valve e.g swelling.
explain valves were stored in a solution containing an antibiotic
- Helps kill any bacteria that could cause an infection in patients
When the valve surgery took place after it there was an increase in minimum blood pressure in the artery explain why the valve from surgery had this affect
(After surgery) valve closes fully / correctly / works so preventing
blood flowing out of the artery
The scientists used the percentage change in the mean resting heart rate after the exercise
programme to compare the results for males and females.
Explain why they used percentage change in the resting heart rate.
Allows comparison;
2. (Initial / resting) heart rates different (between males and females
The scientists calculated the cardiac output of the volunteers before and after the exercise
programme. In some volunteers, their cardiac output stayed the same, even though their
resting heart rate decreased.
Explain how their cardiac output could stay the same even when their resting heart rate
had decreased.
- Cardiac output = stroke volume × heart rate
- Accept CO = SV × HR
(So) stroke volume increases / increased size or volume of ventricles
Lignin is a polymer found in the walls of xylem vessels in plants.
Lignin keeps the xylem vessel open as a continuous tube.
Explain the importance of the xylem being kept open as a continuous tube.
[3 marks]
- (Allows unbroken) water column
OR
(So) no barrier to (water) movement; - Cohesion from H bonds between (all) water
(molecules)
OR - Evaporation/transpiration creates tension
Water moves from xylem (into cells) creates
tension
