2019

• Describe how to do the ruler-drop test


  Hold a ruler just above the open hand of the other student, drop the ruler & other student catches it, then record where the ruler is caught.
• why did group A drink water instead of the caffeine drink?


  to compare the effect of no caffeine
• 2 variables that should be controlled in the investigation of the coffee and drop ruler test

  -same range of age

  -same gender
• Why the ruler-drop test does not involve a reflex action

  Not automatic because it involves the conscious part of the brain.
• name green house gas 


  -methane

  -$CO_2$
• 2 effects of climate change 


  -ice caps melting

  -loss of biodiversity
• Vectors are used in the process of genetic engineering

  -Vectors are used to insert genes into cells

  -Vectors are usually plasmids or viruses
• 2 examples of genetic engineering in use today

  -herbicide resistance

  -crops with improved taste

  -crops resistant to drought
• homeostasis D-

  Control of internal conditions of a body for optimum enzyme activity.
• name the hormone released if the blood glucose concentration falls too low

  Glucagon
• Describe how carbon from the atmosphere is cycled through living organisms

  Photosynthesis:

  • Carbon dioxide is taken in by green plants from the atmosphere through the leaves.
  • It's used in photosynthesis to make glucose (a carbohydrate).
  • Glucose is then used to make other carbon compounds like proteins and lipids or stored as starch.

  Feeding:

  • Animals eat the plants.
  • They use the carbon compounds to build their own biomolecules.

  Decay:

  • When plants and animals die, they are decomposed by microorganisms.
  • These decomposers use the carbon compounds in their cells.

  Respiration:

  • Plants, animals, and microorganisms all respire.
  • Respiration releases carbon dioxide back into the atmosphere, completing the cycle.

  
• Explain why the herbicide-resistant wheat gives a higher yield.[3 marks]

  • Wheat is not affected by herbicide,
  • So competing weeds are killed, allowing wheat to get more light,
  • Which increases photosynthesis, leading to more glucose production and therefore a higher yield.
• Explain one way the Human Genome Project could be important for people in the future.[2 marks]

  • Helps identify genes linked to certain diseases,
  • Which could lead to better treatments for those diseases.
• Draw one line from each animal adaptation to the type of adaptation it is.[2 marks]

  • Male palm cockatoos use sticks to attract females → Behavioural
  • Harmless hornet moth mimics bee/wasp → Structural
  • Sea spiders’ automatic muscle contractions → Functional
• Describe how these adaptations help orchid plants to survive and compete.[4 marks]

  Answer:

  • Growing on other plants means support to absorb more light (for photosynthesis).
  • Bright colours attract pollinators.
  • Large quantities of pollen increases the likelihood of pollen transfer → more seeds/reproduction.
  • Tiny seeds will travel long distances to grow in new areas.
  • Many seeds mean many new plants, so will outcompete other species.
• Question:Describe how an orchid with bright purple flowers may have evolved from the ancestral species which has pale yellow flowers.[4 marks]

  Answer:

  • Mutations for purple flower (in ancestral species).
  • Change in environment e.g. area had more insects.
  • Plants with purple flowers survive and breed.
  • Plants with purple flowers pass on DNA.
  • Until they were so different they could no longer interbreed with the ancestral species.
• Suggest which orchid species is most closely related to the ancestral species.Give a reason for your answer.[2 marks]

  Answer:Species: DReason: Only one amino acid is different.
• Which two improvements would increase the validity of this method?[2 marks]

  Answer (✓):✔ Repeat for another ten quadrats.✔ Use a random method to place the quadrats.
• Q5.3 – Explain how biotic and abiotic factors cause uneven daisy distribution:

  • Trees block light and absorb water/minerals → fewer daisies under trees
  • Trampling on pitches damages plants → fewer daisies
  • Other plants compete for light, water, space → fewer daisies
  • Gardener may water/fertilise some areas → more daisies grow
  • Animals/insects may eat daisies → fewer in those areas
  • Buildings/pollution reduce light or growth → fewer daisies near them
  • Poor soil/pH or drainage in areas → slower growth, fewer daisies
• Person A

  • Type of diabetes: Type 2
  • Reason: Insulin is high but cells don’t respond to it.

  Person B

  • Type of diabetes: Type 1
  • Reason: Insulin is too low because pancreas isn’t producing enough.
• Explain why starving children may die from eating many lychee fruits but children who have eaten during the day are not affected.[6 marks]

  A:Starving children have used up their glycogen stores, so they need the liver enzyme to convert fats into glucose.Lychee contains a molecule that stops this enzyme from working.Without glucose, they can’t respire properly, so they may die.Children who ate during the day still have glycogen in their liver.Glucagon allows glucose to be released from glycogen.This keeps their blood glucose level up, so they survive.