Learning objectives Reflection point 1 Reflection point 2 Reflection point 3 3.19 Explain how the survival of some organisms may depend on the presence of another species: a parasitism, including: i fleas ii headlice iii tapeworms iv mistletoe b mutualism, including: i oxpeckers that clean other species ii cleaner fish 3.20 Analyse, interpret and evaluate data (graphs and tables) on global population change 3.21 Explain how the increase in human population contributes to an increase in the production of pollutants, including phosphates, nitrates and sulfur dioxide 3.22 Explain eutrophication and the problems associated with eutrophication in an aquatic environment 3.23 Investigate the effect of pollutants on plant germination and growth 3.24 Demonstrate an understanding of how scientists can use the presence or absence of indicator species to assess the level of pollution: a polluted water indicator – bloodworm, sludgeworm b clean water indicator – stonefly, freshwater shrimps c air quality indicator – lichen species, blackspot fungus on roses 3.25 Demonstrate an understanding of how recycling can reduce the demand for resources and the problem of waste disposal, including paper, plastics and metals 3.26 Demonstrate an understanding of how carbon is recycled a during photosynthesis plants remove carbon dioxide from the atmosphere b carbon compounds pass along a food chain c during respiration organisms release carbon dioxide into the atmosphere d decomposers release carbon dioxide into the atmosphere e combustion of fossil fuels releases carbon dioxide into the atmosphere Learning objectives Reflection point 1 Reflection point 2 Reflection point 3
allele? (2 marks) First letter of the dominant characteristic with a capitol letter (1) First letter of the dominant characteristic but this time with a lower case letter (1) 8) What do we mean by the terms homozygous and heterozygous? (2 marks) Homozygous – 2 alleles that are the same Heterozygous – 2 alleles that are different 9) What do we mean by the term genotype and phenotype? Give examples (2+2 marks) Genotype – the alleles that have been inherited (1) e.g. Bb or CC or ff (1) Phenotype – the physical characteristic that shows through (1) e.g. Blue eyes, brown eyes, cystic fibrosis, sickle cell trait, (1) 10) Describe the following genotypes – e.g. HH = homozygous dominant (3 marks) a) Bb – Heterozygous b) BB – homozygous dominant c) bb – homozygous recessive 11) What must the genotype be if the recessive trait is going to show through? Explain your answer (2 marks) Homozygous recessive (1) 2 recessive alleles are needed for the characteristic to come through, if a dominant allele is passed on then it would show through rather than the recessive allele(1) 12) Carry out a pedigree analysis for a cross between the following genotypes Bb and bb (2 marks) 1 mark for correct genotypes in the correct box (boxes 1-4 all correct 1 mark for correct offspring (boxes 5-8 all correct) B (1) b (2) b (3) Bb (5) bb (6) b (4) Bb (7) bb (8) 13) B codes for brown eyes and b codes for blue eyes. What is the probability that the offspring of the cross above will have blue eyes? Represent as a ratio and a percentage and a chance out of 4
Produces oil (1), to moisturise the skin (1) 12) Why do we have nerve endings in the skin? (1mark ) To sense temperature and pain (1) 13) What does the central nervous system consist of? (1 mark) Brain and spinal cord. 14) Name the 3 different types of nerves and their roles in the body (3 marks) Sensory nerve – sends information from the receptor to the brain (1) Motor nerve - sends information from the brain to the effector (muscles) (1) Relay nerve – connects sensory nerves to motor nerves (1) 15). Describe the pathway involved when the nervous system coordinates a response (6 marks) Stimulus – receptor – sensory nerve – brain- motor nerve – effector (muscle) – response 16) Describe the pathway of an uncoordinated response (reflex arc) (6 marks) Stimulus – receptor – sensory nerve – RELAY NERVE- motor nerve – effector (muscle) – response 17) What is the role of the myelin sheath on a neurone? (3 marks) Note: Do not say that it protects the neurone, you will not receive marks for this response. Electrical insulator (1), speeds up the electrical impulse (1), Stops the impulse getting lost. 18) A synapse can be found between the relay neurone and sensory and motor nerves. Describe how the impulse travels across a neurone. (4 marks) Presynaptic cell releases neurotransmitters (1), neurotransmitters diffuse across the synapse (1), the neurotransmitters bind to receptors on the post synaptic cell (1), an electrical impulse is triggered on the next neurone (1). 19) Compare the transmission of an impulse (how the impulse is carried) along an axon with transmission across a synapse (2 marks) Axon – electrical impulse (1) Synapse – chemical impulse (1) 20) Why is it an advantage for the axon to be long? (2 marks) Speeds up the impulse