2022

Created by

Arwa

Cards (18)

What reaction produces water
aerobic respiration
Name the process of the water cycle 
1-evaporation
2-condensation
3-precipitattion
4-draining
5-tranpiration
Why do more people have severe water shortages now than in 2007
-Climate change has increased the area of deserts
-More water is used to grow crops
One benefit of fallen leaves for living plants
nitrate are released into the soil
One biotic factor which may affect the number of buttercups growing on the field
pathogens/herbivores/pollinators
Leaves on a tree contain carbon compounds.In autumn the leaves fall to the ground.
Q:Microorganisms in the soil recycle carbon from the leaves so that the carbon is used for new plant growth.
Explain how.
[4 marks]
• Decomposition of leaves
• Respiration by microorganisms
• Respiration OR microorganisms release CO₂
• CO₂ is used in photosynthesis (for new plant growth)
Explain how human activities are polluting rivers, lakes, and seas.
[6 marks]
• Fertilisers and sewage enter waterways, causing eutrophication → algae grow rapidly → block light → plants die → decomposers break them down → oxygen levels fall → habitats are destroyed
• Pesticides and microplastics build up in organisms (bioaccumulation) → harm or kill wildlife
• Industrial waste (e.g. toxic, radioactive chemicals) pollutes water and harms local ecosystems
Describe a method to investigate if the amount of water in the soil affects the number of buttercups in the field.
[6 marks]
• Set up two 10m x 10m grids: one in a wet area, one in a dry area
• Use a random number generator to place quadrats in each grid
• Count buttercups in each quadrat and record in a table
• Measure soil moisture at each quadrat using a moisture meter
• Repeat 5–10 times for each grid
• Calculate mean buttercups per grid and estimate total using area (100m²)
Investigation Summary:Scientists tested how different soil nitrate ion concentrations affect the yield (mass) of corn plants.
Q Give two variables the scientists should have controlled in this investigation.
[2 marks]
light (intensity) or temperature
water or soil type
Q Farmers add nitrate fertiliser to fields where they grow corn.
Nitrate fertilisers are expensive.
Evaluate the economic and environmental implications of adding fertiliser to soil in nitrate ion concentrations ranging from 0 to 50 ppm.
[4 marks]
• Nitrate up to 30 ppm increases yield → more profit
• Over 30 ppm reduces yield → waste of money
• Need to test soil before adding fertiliser to avoid overuse
• Excess nitrate may wash into rivers/lakes → causes pollution
Q 05The body must keep blood glucose levels within a normal range.
Figure 4 shows how two hormones from the pancreas control blood glucose concentration when it's too low or too high.
Q 05.1Name the type of hormonal control shown in Figure 4.
[1 mark]
A: Negative feedback
Q 05.2Name hormones A and B in Figure 4.
[1 mark]A: GlucagonB: Insulin
Explain how the two hormones in Figure 4 keep the blood glucose concentration within the normal range for 3 hours after a meal.
[6 marks]
Summary Answer:
After a meal, blood glucose rises → pancreas releases insulin (B) → glucose taken into cells and stored as glycogen → blood glucose falls → pancreas stops insulin.
When blood glucose drops → pancreas releases glucagon (A) → glycogen broken back into glucose → glucose released into blood → glucose rises again.
This cycle keeps blood glucose levels stable. Glucagon stops being released when levels are high again.
Follicle Stimulating Hormone (FSH) and then Luteinising Hormone (LH) can be injected into a woman to help her become pregnant by sexual intercourse.
Explain how injecting FSH and then LH will help a woman to become pregnant.
[3 marks]
A:
FSH stimulates egg cells in the ovaries to mature, while LH causes the matured egg to be released from the ovaries at ovulation. The 2 hormones together will cause several eggs to mature and be released. As there are more eggs there is a higher probability of sperm fusing with one leading to fertilisation.
In some women the injections of FSH and LH are the first steps for In Vitro Fertilisation (IVF).
Describe the remaining steps in IVF.
[4 marks]
A:The eggs that have matured and been released are collected from the ovary. These then get fertilised in a lab. These fertilised eggs get supplied with nutrients, so that they develop into embryos. These developed embryos are then inserted into the womb of the mother where they embed into the lining of the uterus and develop.
There are two different processes of cell division in humans.
Describe three differences between cell division to form sperm cells compared with cell division to form liver cells.[3 marks]
A:
To form liver cells the cells only go through one division, while for a sperm cell they go through 2 sets of divisions.
The 2 liver cells would be genetically identical to each other, while the four sperm cells would be genetically unique.
Sperm cells are haploid, so have 23 chromosomes, while liver cells would have 23 pairs so 46 chromosomes.
e:g of polar bear
Domain: EukaryoteKingdom: AnimaliaPhylum: chordataClass: mammaliaOrder: carnivoraFamily: ursidaeGenus: UrsusSpecies: maritimus
Q Suggest why polar bears find it harder to catch seals in autumn than in spring.
[2 marks]
• There is fewer seals left on ice accessible for polar bears to catch. Also young seals have grown up so can avoid/escape a polar bear more easily by swimming away.
Q 06.4Evaluate what might happen to the population of polar bears in the Arctic in the future.
[4 marks]
Populations may increase as more laws are put in place to protect their habitat, food source and themselves from hunting. We might be able to stop CO₂ emissions and stop global warming destroying their habitat. However, their population can decrease if global warming continues and melts more and more sea ice. This gives them less hunting ground and requires more energy to hunt fewer individual seals. This also makes it harder for them to find mates and reproduce.