2025 predicted primrose

• reflex action(why are some responses reflex)?

  -no neurons from the brain/connected to the brain

  -coordinated only by the spinal cord
• Importance of reflex actions

  -automatic/rapid response

  -protects the body from harm/from damage
• Explain how impulses are transmitted at the synapse

  -Electrical impulse stimulates the release of chemicals

  -Chemical diffuses across the gap/synapse

  -Binds to receptors to stimulate an electrical impulse in the next neurone.
• allele meaning

  a different version/form of a gene
• abiotic factor

  light intensity
• Biotic factors affecting the distribution of daisies

  -pathogens

  -herbivores

  -competition
• Carbon dioxide is released into the atmosphere

  respiration/decay/decomposition by

  decomposers/fungi/bacteria
• Human activity has disrupted the carbon cycle and led to an increase in carbon dioxide in the atmosphere.

  Human activities that have led to greater carbon dioxide levels in the atmosphere:

  -combustion

  -burning of fossil fuels

  -deforestation
• greenhouse eg.

  carbon dioxide
• Increasing CO2 in the atmosphere has contributed to global warming and climate change. How?

  reduce heat radiated by Earth into space.

  heat radiated back to Earth.
• global warming and climate change affect biodiversity .2 methods used to conserve biodiversity can help humans to reduce their impact on ecosystems

  • Breeding programmes

  • Reintroducing hedgerows

  • Reduce deforestation

  • Reduce CO₂ emissions

  • Recycling resources to reduce waste

  • Reduce use of pesticides/herbicides
• Explain why the use of pesticides can reduce biodiversity in rivers close to farms

  pesticide runs off fields into rivers.

  -kills insects in rivers, which affects the food chain/webs /ecosystem
• Why are certain plants of the same species resistant to something specific, but others are not?

  -different alleles

  -different mutations

  -Genetic variation in the population
• cattle farming = increase in global warming

  More cows release more methane-which is a greenhouse gas.
• Meat consumption is expected to increase in the future = more farmland is needed. Suggest a reason for the increase and describe what impact increasing farmland could have on ecosystems.

  
  

  More people/population increase

  Any two from:

  • Less food crops will be grown

  • More deforestation leading to biodiversity loss/decrease

  • More deforestation leading to habitat loss

  • Methane contributes to climate change causing extreme weather or changes in migration patterns

  • Deforestation leading to soil erosion/flooding
• Describe the structure of DNA

  -DNA is a polymer made up of 2 strands

  -forming a double helix
• Explain why religious people opposed Darwin's theory of evolution

  -believed that god made all things

  -believed that humans have been on earth since the beginning
• Why was it hard in the 1800s for Darwin to prove his theory of evolution was correct

  -not enough fossil evidence

  -DNA had not yet been discovered
• describe the type of fossils that are produced by plants.

  imprints
• explain why plant fossils are rarer than fossils of many animal species

  No hard parts, only soft parts decay

  -Conditions for formation are very rare/easily damaged/hard to find.
• state what hormones the oral contraceptive pill usually contains

  -Oestrogen

  -Progesterone
• Model Answer (using transect method):

  Lay a transect line from the shaded woodland to the sunnier play area. Place quadrats at regular intervals along the transect. In each quadrat, count the number of daisies and measure the light intensity using a light meter. Repeat the transect in different locations to improve reliability. Calculate the average number of daisies for each light level. Plot a graph of light intensity against the number of daisies and analyse the trend to see if higher light levels are linked to more daisies.
• Method 1: Transect Method

  • Lay a tape measure (transect line) from the woodland (shady area) to the open field or play area (sunny area).
  • Place quadrats at regular intervals (e.g. every 1 metre) along the transect.
  • In each quadrat, count the number of daisies.
  • Use a light meter to measure the light intensity in each quadrat.
  • Repeat the transect in other similar locations to improve reliability.
  • Calculate the mean number of daisies at each light intensity level and plot a graph to see if there is a correlation.
• Method 2: Random Sampling Method

  • Use a grid method and random number generator to choose random coordinates in both shaded (near woodland) and sunny (open field) areas.
  • Place a large number of quadrats at these random coordinates.
  • Count the number of daisies in each quadrat.
  • Use a light meter to measure the light intensity in each quadrat.
  • Calculate the mean number of daisies for different light intensity levels.
  • Plot or analyse the data to identify any relationship between light intensity and the number of daisies.
• c) The students hypothesised that there was more shade near the woodland, and this was affecting the distribution of daisies. Their hypothesis was that:“As light intensity increases, the number of daisies increases.”

  Plan an investigation to test this hypothesis.[6 marks]
• Describe how the scientists could produce a population of peppers resistant to the tomato ringspot virus.

  [4 marks]

  Answer:

  1. Choose two pepper plants that show resistance to the tomato ringspot virus.
  2. Cross-breed or pollinate these resistant pepper plants.
  3. From the offspring, select the plants that show the strongest resistance to the virus.
  4. Repeat the breeding process over several generations until all the plants consistently show resistance to the virus (they breed true).
• A news article was recently published with the following headline:Women are turning their back on the pill!More women than ever are ditching the pill and condoms in favour of "long-acting reversible contraceptives", including the IUD and implant.

  evaluate whether it supports the headline and suggest some reasons to explain the changes in contraception use.You should include a reasoned conclusion in your answer.[5 marks]

  Answer:The graph shows a steady rise in IUD/implant use since 2006 and a drop in pill/condom use from 2014, which supports the headline. However, more women still use the pill overall, so the headline slightly exaggerates.

  Many may switch because the IUD lasts longer and doesn’t require daily use. The pill must be taken daily and can cause side effects like headaches and blood clots.

  Conclusion:The headline is mostly supported, but the pill is still more common, so it’s an overstatement.
• carbon cycle process

  • Photosynthesis
  • Respiration
  • Feeding
  • Decomposition
  • Combustion
  • Fossilisation
  • Decay
  • Excretion
  • Death