OCR GCSE 9-1 Gateway Biology A Paper 2 Paper 4 separate science A for 2023 2024 2025 exams past papers 2018 2019 2020 2021 2022 Topics B4 Community level systems B5 Genes, inheritance and selection B6 Global challenges revision notes

Revising summary help for the separate science OCR Gateway Science A GCSE 9-1 BIOLOGY A 2nd Exam Paper

OCR Level 1/2 GCSE (Grade 9-1) in Biology A (Gateway Science) (J247) Foundation Tier Paper 2/Higher Tier Paper 4 - OCR 9-1 Gateway GCSE BIOLOGY A Topic B4 "Community level systems", Topic B5 "Genes, inheritance and selection", Topic B6 "Global challenges", Topic B7 "Practical skills" for Gateway 2020 GCSE biology exam papers onwards

PLEASE READ CAREFULLY THE FOLLOWING POINTS before using my OCR Gateway 9-1 GCSE science pages

Syllabus-specification CONTENT INDEX of revision summary notes (OCR GCSE Gateway science suite biology)

Revision summary OCR Gateway Science GCSE 9-1 BIOLOGY A FT Paper 1/HT Paper 3 (separate page)

What is assessed in this paper? (for OCR 9-1 GCSE Gateway separate science GCSE BIOLOGY)

The 1st biology paper assesses Topics B1, B2, B3 and B7 (OCR GCSE Gateway science suite biology)

Revision summary OCR Gateway Science GCSE 9-1 BIOLOGY A FT Paper 2/HT Paper 4 (this page)

What is assessed in this paper? (for OCR 9-1 GCSE Gateway separate science GCSE BIOLOGY)

The 2nd biology paper assesses Topics B4, B5, B6 and B7, BUT assumes knowledge of Topics B1, B2, B3

(Revision for OCR Gateway Science GCSE 9-1 BIOLOGY A, Topic B4 "Community level systems", FT Paper 2/HT Paper 4)

The 2nd biology paper assesses Topics B4, B5, B6 and B7, BUT assumes knowledge of Topics B1, B2 and B3

(Revision for OCR Gateway Science GCSE 9-1 BIOLOGY A, Topic B4 "Community level systems", FT Paper 2/HT Paper 4)

Microorganisms play an important role in the continuous cycling of chemicals in ecosystems. Biotic and abiotic factors interact in an ecosystem and have an effect on communities. Living organisms form populations of single species, communities of many species and are part of ecosystems. Living organisms are interdependent and show adaptations to their environment. Feeding relationships reflect the stability of an ecosystem and indicate the flow of biomass through the ecosystem.

You should be familiar with the idea of a food web and the interrelationships associated with them and that variation allows living things to survive in the same ecosystem.

You should also recognise that organisms affect their environment and are affected by it.

Be able to explain the consequences on a food web if the producers are removed for some reason than if the top predators are taken away.

You may find arrows showing the flow of biomass from one trophic level to another quite challenging and often mistake it for the direction of predation. This makes problems relating to the manipulation of a food web quite difficult for some students.

Be able to calculate rate changes in the decay of biological material, calculate the percentage of mass, plot and draw appropriate graphs selecting appropriate scales for the axes, extract and interpret information from charts, graphs and tables.

B4.1a Be able to recall that many different materials cycle through the abiotic and biotic components of an ecosystem - examples of cycled materials e.g. nitrogen and carbon

B4.1b Be able to explain the role of microorganisms in the cycling of materials through an ecosystem - the role of microorganisms in decomposition. Research into the range of ecosystems and examples of micro-organisms that act as decomposers within them.

B4.1c Be able to explain the importance of the carbon cycle and the water cycle to living organisms including maintaining habitats, fresh water flow of nutrients

B4.1d Be able to explain the effect of factors such as temperature, water content, and oxygen availability on rate of decomposition, including the terms aerobic and anaerobic Investigation of the most favourable conditions for composting.

B4.1e Be able to describe different levels of organisation in an ecosystem from individual organisms to the whole ecosystem

B4.1f Be able to explain how abiotic and biotic factors can affect communities including temperature, light intensity, moisture level, pH of soil, predators, food. Identification of the biotic factors in an ecosystem using sampling techniques.

B4.1g Be able to describe the importance of interdependence and competition in a community including interdependence relating to predation, mutualism and parasitism. Examination of the roots of a leguminous plant e.g. clover to observe the root nodules Investigation of the holly leaf miner or the horse-chestnut leaf miner (Cameraria ohridella)

B4.1h Be able to describe the differences between the trophic levels of organisms within an ecosystem including use of the terms producer and consumer Investigation of the trophic levels within a children’s story (e.g. the Gruffalo)

B4.1i Be able to describe pyramids of biomass and be able to explain, with examples, how biomass is lost between the different trophic levels including loss of biomass related to egestion, excretion, respiration. Discussion of the best food source for humans (e.g. ‘wheat vs. meat’) Production of ecological pyramids.

B4.1j Be able to calculate the efficiency of biomass transfers between trophic levels and explain how this affects the number of trophic levels in a food chain. Be able to calculate of the biomass transfers using real data

Topic B5: Genes, inheritance and selection (OCR GCSE Gateway science suite biology)

(Revision for OCR Gateway Science GCSE 9-1 BIOLOGY A, Topic B5 "Genes, inheritance and selection", FT Paper 2/HT Paper 4)

Know that inheritance relies on the genetic information contained in the genome being passed from one generation to the next, whether sexually or asexually. The characteristics of a living organism are influenced by the genome and its interaction with the environment.

You should be familiar with the idea of heredity as the process by which genetic information is passed from one generation to the next. You should have encountered a simple model of chromosomes, genes and DNA.

Common misconceptions - the physical relationships between the nucleus, genetic material, the genome, chromosomes and genes. Accurate definitions of these terms will help you explanations in this topic. You may have explanations for inheritance before undertaking GCSE study. Some examples include that intra-specific variation is as a result of defects in development or that acquired characteristics can be inherited. Care must also be taken with the concept of dominant and recessive alleles. Whether an allele is dominant or recessive does not affect the mechanism of inheritance of the allele, but is an observed pattern in the phenotype of organisms. Many of you assume that the dominant allele ‘dominates’ the recessive allele preventing its expression (which is not the case) or that the recessive allele is actually just an absence of the dominant allele (also not generally the case).

B5.1a Be able to explain the following terms: gamete, chromosome, gene, allele/ variant, dominant, recessive, homozygous, heterozygous, genotype and phenotype Use of a alleles to work out the phenotype of progeny

B5.1b Be able to describe the genome as the entire genetic material of an organism

B5.1c Be able to describe that the genome, and its interaction with the environment, influence the development of the phenotype of an organism - use of examples of discontinuous and continuous variation e.g. eye colour, weight and height

B5.1d Recall that all variants arise from mutations, and that most have no effect on the phenotype, some influence phenotype and a very few determine phenotype

B5.1e (HT only) Be able to describe how genetic variants may influence phenotype:

B5.1f Be able to explain some of the advantages and disadvantages of asexual and sexual reproduction in a range of organisms including the number of live offspring per birth, how quickly the organisms can reproduce verses the need for the introduction of variation in a population caused by environmental pressures

B5.1h Be able to explain the role of meiotic cell division in halving the chromosome number to form gametes - that this maintains diploid cells when gametes combine and is a source of genetic variation

B5.1i Be able to explain single gene inheritance in the context of homozygous and heterozygous crosses involving dominant and recessive genes. Prediction of the probability of phenotype for genetic crosses. Investigation into probability by suitable example (e.g. coin toss or die roll)

B5.1l Be able to recall that most phenotypic features are the result of multiple genes rather than single gene inheritance

B5.1m Be able to describe the development of our understanding of genetics, including the work of Mendel

B5.2 Natural selection and evolution (OCR GCSE Gateway science suite biology)

(Revision for OCR Gateway Science GCSE 9-1 BIOLOGY A, Topic B5 "Genes, inheritance and selection", FT Paper 2/HT Paper 4)

Know that variation in the genome and changes in the environment drive the process of natural selection, leading to changes in the characteristics of populations. Evolution accounts for both biodiversity and how organisms are all related to varying degrees. Key individuals have played important roles in the development of the understanding of genetics.

You should appreciate that changes in the environment can leave some individuals, or even some entire species, unable to compete and reproduce leading to extinction.

Common misconceptions You are used to hearing the term evolution in everyday life but it is often used for items that have been designed and gradually improved in order to fit a purpose you need to grasp the idea that evolution by natural selection relies on random mutations. You also tend to imply that individuals change by natural selection. Statements such as ‘a moth will change by natural selection in order to become better camouflaged’ include both of these common misconceptions.

B5.2a Be able to state that there is usually extensive genetic variation within a population of a species

B5.2b Be able to describe the impact of developments in biology on classification systems - natural and artificial classification systems and use of molecular phylogenetics based on DNA sequencing

B5.2c Be able to explain how evolution occurs through the natural selection of variants that have given rise to phenotypes best suited to their environment - the concept of mutation

B5.2d Be able to describe evolution as a change in the inherited characteristics of a population over time, through a process of natural selection, which may result in the formation of new species

B5.2e Be able to describe the evidence for evolution - fossils and antibiotic resistance in bacteria

B5.2f Be able to describe the work of Darwin and Wallace in the development of the theory of evolution by natural selection and explain the impact of these ideas on modern biology - seedbanks being used as a store of biodiversity

(Revision for OCR Gateway Science GCSE 9-1 BIOLOGY A, Topic B6 "Global challenges", FT Paper 2/HT Paper 4)

This topic seeks to integrate you’ knowledge and understanding of biological systems and processes, with the aim of applying it to global challenges. Biological information is used to help people to improve their own lives and strive to create a sustainable world for future generations. This topic provides opportunities to draw together the concepts covered in earlier topics, allowing synoptic treatment of the subject.

B6.1 Monitoring and maintaining the environment (OCR GCSE Gateway science suite biology)

Know that living organisms interact with each other, the environment and with humans in many different ways. If the variety of life is to be maintained we must actively manage our interactions with the environment. We must monitor our environment, collecting and interpreting information about the natural world, to identify patterns and relate possible cause and effect.

From topic B4, you should be familiar with ecosystems and the various ways organisms interact.

It is important that in the study of this topic you explore both positive and negative human interactions within ecosystems.

B6.1a Be able to explain how to carry out a field investigation into the distribution and abundance of organisms in a habitat and how to determine their numbers in a given area - sampling techniques (random and transects, capture-recapture), use of quadrats, pooters, nets, keys and scaling up methods Investigation of ecological sampling methods. Using the symbols =, <, <<, >>, >, α, ~ in answers where appropriate. Investigation of sampling using a suitable model (e.g. measuring the red sweets in a mixed selection).

B6.1b Be able to describe both positive and negative human interactions within ecosystems and be able to explain their impact on biodiversity - the conservation of individual species and selected habitats and threats from land use and hunting. Investigation into the effectiveness of germination in different strengths of acid rain. Investigation into the effects of lichen distribution against pollution.

B6.1c Be able to explain some of the benefits and challenges of maintaining local and global biodiversity including the difficulty in gaining agreements for and the monitoring of conservation schemes along with the benefits of ecotourism

B6.1d (HT only) Be able to evaluate the evidence for the impact of environmental changes on the distribution of organisms, with reference to water and atmospheric gases

The human population is increasing rapidly and with this comes a need for more food. Biologists are seeking to tackle this increased demand, which will lead to an improvement in the lives of many people around the world. However, there are many things to consider in achieving this aim, not least the impact on ecosystems. There is much debate surrounding the use of gene technology as a potential solution to the problem of food security.

You should be familiar with the content of a healthy human diet and the consequences of imbalances in a healthy daily diet.

Your knowledge and understanding from topics 1, 4 and 5 will also be drawn together in this topic. This includes the organisation of DNA, what plants require enabling them to photosynthesise, interactions between species and the idea of variability within species and subsequent selection of characteristics.

Common misconceptions - you can often think that genetic engineering leads to the increased use of pesticides.

B6.2a Be able to describe some of the biological factors affecting levels of food security - increasing human population, changing diets in wealthier populations, new pests and pathogens, environmental change, sustainability and cost of agricultural inputs

B6.2b Be able to explain some possible agricultural solutions to the demands of the growing human population - increased use of hydroponics, biological control, gene technology, fertilisers and pesticides.

B6.2c Be able to explain the impact of the selective breeding of food plants and domesticated animals. Research into the Rothamsted Research Broadbalk experiment.

B6.2d Be able to describe genetic engineering as a process which involves modifying the genome of an organism to introduce desirable characteristics

B6.2e (HT only) Be able to describe the main steps in the process of genetic engineering including restriction enzymes, sticky ends, vectors e.g. plasmids, ligase, host bacteria and selection using antibiotic resistance markers

B6.2f Be able to explain some of the possible benefits and risks of using gene technology in modern agriculture - to include practical and ethical considerations. Research into the advantages and disadvantages of selective breeding and genetic engineering.

B6.2g Be able to explain some possible biotechnological solutions to the demands of the growing human population - genetic modification Research into the growth of GM crops or livestock.

B6.3 Monitoring and maintaining health (OCR GCSE Gateway science suite biology)

Know that diseases affect the health of populations of both humans and plants. Scientists are constantly on the lookout for ways of preventing and combating disease. The prevention of disease in plants is important so that we are able to grow healthy plants enabling us to feed ourselves and enhance our environment. The understanding of how disease is spread, how our bodies defend themselves against disease and how immunity is achieved is essential to enable us to combat potentially fatal diseases spreading throughout whole populations. Non-communicable diseases also have an impact on the health of the population. The prevention of these diseases is frequently discussed in the media, with advice being given to us on how to reduce our risk of contracting these diseases through our life-style choices and discussion of new technologies.

You should be familiar with the effects of ‘recreational’ drugs (including substance misuse) on behaviour, health and life processes, the impact of exercise, asthma and smoking on the gas exchange system and the consequences of imbalances in the diet, including obesity, starvation and deficiency diseases.

Common misconceptions - all micro-organisms as being non-beneficial. You tend to consider health as just physical and do not consider mental health. You also confuse which diseases are inherited and which are caught. You see cancer as a genetic disease.

Be able to understand the principles of sampling as applied to scientific data. Be able to use a scatter diagram to identify a correlation between two variables. Be able to calculate cross-sectional areas of bacterial cultures and clear agar jelly using πr²

B6.3b Be able to describe different types of diseases including communicable and non-communicable diseases

B6.3c Be able to describe the interactions between different types of disease including HIV and tuberculosis, and HPV and cervical cancer

B6.3d Be able to explain how communicable diseases (caused by viruses, bacteria, protists and fungi) are spread in animals and plants including scientific quantities, number of pathogens, number of infected cases and estimating number of cases

B6.3e Be able to explain how the spread of communicable diseases may be reduced or prevented in animals and plants - detection of the antigen, DNA testing, visual identification of the disease by a plant pathologist.

B6.3f Be able to describe a minimum of one common human infection, one plant disease and sexually transmitted infections in humans including HIV/AIDS including plant diseases: virus tobacco mosaic virus, fungal Erysiphe graminis barley powdery mildew, bacterial Agrobacterium tumafaciens crown gall disease

B6.3g Be able to describe physical plant defence responses to disease - leaf cuticle, cell wall

B6.3h Be able to describe chemical plant defence responses - antimicrobial substances

B6.3i (HT only) Be able to describe different ways plant diseases can be detected and identified, in the lab and in the field including the laboratory detection of the DNA or antigen from the disease causing organism. The field diagnosis by observation and microscopy.

B6.3j Be able to explain how white blood cells and platelets are adapted to their defence functions in the blood

B6.3k Be able to describe the non-specific defence systems of the human body against pathogens

B6.3l Be able to explain the role of the immune system of the human body in defence against disease

B6.3n (HT only) Be able to describe some of the ways in which monoclonal antibodies can be used including their role in detecting antigens in pregnancy testing, detection of diseases (prostate cancer) and potentially treating disease (targeting cancer cells)

B6.3o Be able to explain the use of vaccines and medicines in the prevention and treatment of disease including antibiotics, antivirals and antiseptics Research into whether children should be routinely vaccinated?

B6.3p Be able to explain the aseptic techniques used in culturing organisms including use of alcohol, flaming, autoclaving of glassware and growth media, and measures used to stop contaminants falling onto/into the growth media (e.g. working around a Bunsen burner) Investigation into growth bacterial cultures using aseptic techniques.

B6.3q describe the processes of discovery and development of potential new medicines - preclinical and clinical testing. Investigation into growth bacterial cultures using aseptic techniques.

B6.3r Be able to recall that many non-communicable human diseases are caused by the interaction of a number of factors including cardiovascular diseases, many forms of cancer, some lung and liver diseases and diseases influenced by nutrition, including type 2 diabetes

B6.3s Be able to evaluate some different treatments for cardiovascular disease to including lifestyle, medical and surgical

B6.3t Be able to analyse the effect of lifestyle factors on the incidence of non-communicable diseases at local, national and global levels including lifestyle factors to include exercise, diet, alcohol and smoking

B6.3u Be able to describe cancer as the result of changes in cells that lead to uncontrolled growth and division

B6.3v Be able to discuss potential benefits and risks associated with the use of stem cells in medicine including tissue transplantation and rejection

B6.3w Be able to explain some of the possible benefits and risks of using gene technology in medicine including practical and ethical considerations

B6.3x Be able to discuss the potential importance for medicine of our increasing understanding of the human genome including the ideas of predicting the likelihood of diseases occurring and their treatment by drugs which are targeted to genomes