2018 Paper 1 Flashcards
explain why a person with AIDS will take a longer time to recover than a person with salmonella
AIDS is when the immune system can no longer defend itself properly so the white blood cells cannot kill bacteria as effectively than a person with salmonella could
suggest one way other than vaccines, farmers could stop the spread of salmonella from chickens to humans
don’t sell the infected chicken or its eggs
( or give the chicken antibiotics)
what change could be made to the bacteria in dish experiment see if results are repeatable
repeat and look to see if the results are similar!
give one metabolic reaction in cells
respiration
give to substances carried in the plasma ( other than urea)
carbon dioxide, hormones
design an investigation to test whether smokers’ heart rate increases more than non-smokers during exercise
get 2 groups of people - smokers and non-smokers - with at least 5 people in each group
record their initial heart rate using a heart rate monitor
get them all to do the same exercises ( eg cardio exercises like running or treadmill) for 10 mins. time them using stop watch
after 10 mins record the heart rate
work out the increase in heartbeat for each person then work out a mean increase in heart rate for both groups.
COMPARE results
control variables = age, gender, duration of exercise, type of exercise
Explain how the student could modify the investigation to determine the concentration
of the solution inside each egg
use five (or more) different
concentrations of salt / sugar
solution (in beakers)
(by) plotting percentage change
(in mass / volume) on / using a
graph
determine the concentration
where the curve / line crosses
the zero percentage change (in
mass / volume)
Explain how a deficiency in magnesium could cause yellow leaves and stunted growth
Yellow leaves is as a result of a lack of chlorophyll. Therefore less light is absorbed and photosynthesis takes place at a lower rate. Therefore less glucose is produced so less glucose is converted into protein which is needed for growth
Explain why children with cistic fibrosis grow more slowly than children without
If mucus blocks the ducts from pancreas, less digestive enzymes like amylase and lipase can enter small intestine so digestive enzymes break down less food, so less nutrients and amino acids are absorbed into the bloodstream which is needed for growth. If aveoli is blocked by mucus, less oxygen travels around the body in red blood cells so less energy is available for aerobic respiration resulting in less energy released that is available for growth
What molecules are genes made up of
DNA
Describe how a scientist may use stem cells to create healthy lungs that are not rejected by cistic fibrosis patients
Get stem cells from bone marrow
Remove the CF gene
Create an embryo using stem cells
Remove stem cells from embryo before they differentiate and allow them to differentiate into lung cells
Describe how a student could test cows milk to show weather it contains proteins and different types of carbohydrate
Pour 20cm cubed cows milk into a test tube
Pour a couple of drops of biuret reagent into solution. It will go from blue to purple if milk contains protein
Use iodine to test for starch by adding a couple of drops of iodine into test tube. Solution will go from orange to blue black if starch is present
To test for sugars use Benedict’s reagent. Add benidicts reagent to the milk and heat it in a water bath above 60 degrees. If sugar is present solution will go from blue to brick red
How does bile help break down fat
Bile emulsifies fat, creating a larger surface area so lipase can break down fat more effectively
What does lipase break fat into
Fatty acids and glycerol
Acid lowers the pH
Compare structure of arteries to veins
Arteries have thicker muscular walls with elastic fibres but veins have thin walls
Arteries have narrower lumen but veins have wider lumen
Veins have valves to stope the back flow of blood and arteries do not
