Biology

subject overview

We follow the AQA syllabus in Biology. The course is split in three units at both AS and A2 stages.

Learners will take their terminal examination in June. They will study the following units at AS:

•Unit 1: Biology and Disease

•Unit 2: The Variety of Living Organisms

•Unit 3: Practical and Investigative Skills (20% of total AS marks, 10% of total A Level marks)

The learners will study the following units during the A2 units:

•Unit 4: Populations and Environment

•Unit 5: Control in Cells and in Organisms

•Unit 6: Practical and Investigative Skills (10% of the total A Level marks)

unit overview - autumn term

Inherited change, population, stimuli, evolution
Skills	After finishing this topic, students will gain the following skills- AT h Students could investigate genetic ratios using crosses of Drosophila or Fast Plant® Students could use the test to investigate the significance of differences between expected and observed phenotypic ratios AT k Students could collect data about the frequency of observable phenotypes within a single population. Analyse data on base frequency and apply knowledge of base pairing, to work out frequency of other bases. Interpret DNA sequence and applying knowledge to work out complementary mRNA code. Develop and apply knowledge and understanding about properties of water related to their significance to life Required practical 12: Investigation into the effect of a named environmental factor on the distribution of a given species. After carrying out the practical tasks in this topic, students will gain the following skills- AT k Students could collect data about the frequency of observable phenotypes within a single population. Students could apply their knowledge of sampling to the concept of genetic drift. AT l Students could use computer programs to model the effects of natural selection and of genetic drift. AT k Students could: investigate the distribution of organisms in a named habitat using randomly placed frame quadrats, or a belt transect use both percentage cover and frequency as measures of abundance of a sessile species. AT h Students could use the mark-release-recapture method to investigate the abundance of a motile species. AT i Students could use turbidity measurements to investigate the growth rate of a broth culture of microorganisms. Students could use a logarithmic scale in representing the growth of a population of microorganisms. Required practical 10: Investigation into the effect of an environmental variable on the movement of an animal using either a choice chamber or a maze. AT h Students could design and carry out investigations into: the sensitivity of temperature receptors in human skin, habituation of touch receptors in human skin, resolution of touch receptors in human skin. Students should be able to use information provided to predict and explain the effects of specific drugs on a synapse. AT d Students could examine prepared slides of skeletal muscle using an optical microscope. AT h Students could investigate the effect of repeated muscular contraction on the rate of muscle fatigue in human volunteers. AT k Students could collect data about the frequency of observable phenotypes within a single population. AT l Students could use computer programs to model the effects of natural selection and of genetic drift.
Knowledge	Monohybrid inheritance, probability ad genetic crosses, dihybrid inheritance, co dominance and multiple alleles, sex linkage, autosomal linkage, epitasis, chi square test. Populations in ecosystems, variation in population size, competition, predation, investigating populations, succession, conservation of habitats. Response to stimulus, nervous coordination and muscles. Population genetics, variation in phenotype, natural selection, effects of different forms of selection on evolution, isolation and speciation
Rationale	The study of human DNA and genetics can be intellectually fascinating, but it also has plenty of practical applications. From the use of DNA in court cases to the discovery of new therapies for genetic diseases, a thorough understanding of the human genome can have important medical, social and legal impacts. Understanding the genetic basis behind human disease is one of the most important reasons for studying the human genome. While many genetic disorders are not treatable, early diagnosis can help improve the quality of life or even extend the lifespan of sufferers. Current clinical trials on genetic therapies for cystic fibrosis, haemophilia, and other genetic disorders offer the promise of eventual treatments that may give sufferers a life free of symptoms. Genetics helps explain a lot of things, like what makes you unique, why you look like other members of your family, and why some diseases run in your family. The theory of evolution is fundamental to biology. It states that all new species arise from existing ones by the process of natural selection. This section will add to the knowledge of variation and natural selection from GCSE. In this section, the students will learn to use ratios, fractions, logarithms and percentages, find arithmetical means, understand simple probability, understand the principles of sampling when applied to scientific data, select and use a stastical test and solve algebraic problems. It also shows the sequence of events involved in transmission across a cholinergic synapse in sufficient detail to explain: unidirectionality, temporal and spatial summation, inhibition by inhibitory synapses. A comparison of transmission across a cholinergic synapse and across a neuromuscular junction. The roles and locations of chemoreceptors and pressure receptors and the roles of the autonomic nervous system and effectors in controlling heart rate. This knowledge can be applied to predict and explain the effects of specific drugs on a synapse. This unit gives a clear indication that population of different species live in communities. Competition occurs within and between the populations for the means of survival. It also throws light on the history of evolution and natural selection. Students can apply this knowledge to know the variation in phenotypes and speciation.

unit overview - spring term

Gene expression, homeostasis
Skills	After finishing this topic, students will gain the following skills- AT i Students could produce tissue cultures of explants of cauliflower Students should be able to relate the nature of a gene mutation to its effect on the encoded polypeptide. Students should be able to evaluate the use of stem cells in treating human disorders. Required practical 11: Production of a dilution series of a glucose solution and use of colorimetric techniques to produce a calibration curve with which to identify the concentration of glucose in an unknown ‘urine’ sample. Students should be able to interpret information relating to examples of negative and positive feedback. Students should be able to evaluate the positions of health advisers and the food industry in relation to the increased incidence of type II diabetes.
Knowledge	Gene mutations, stem cells and totipotency, regulation of transcription and translation, gene expression and cancer, genome projects Principle of homeostasis, feedback mechanisms, control of blood sugar concentration, control of blood water concentration, the roles of hormones in osmoregulation.
Rationale	This section gives the understanding of correlations between genetic and environmental factors and various forms of cancer. It can be used to interpret information relating to the way in which an understanding of the roles of oncogenes and tumour suppressor genes could be used in the prevention, treatment and cure of cancer This section also gives a picture that gene mutations occur spontaneously, the mutation rate is increased by mutagenic agents and can result in a different amino acid sequence in the encoded polypeptide. Sequencing projects have read the genomes of a wide range of organisms, including humans. Determining the genome of simpler organisms allows the sequences of the proteins that derive from the genetic code (the proteome) of the organism to be determined. This may have many applications, including the identification of potential antigens for use in vaccine production. This topic explains a meaning and significance of homeostasis to students. It is advantageous to maintain constant internal environment. Homeostasis in mammals involves physiological control systems that maintain the internal environment within restricted limits.

unit overview - summer term

Recombinant gene technology, Survival and response
Skills	After finishing this topic, students will gain the following skills- AT g Students could investigate the specificity of restriction enzymes using extracted DNA and electrophoresis. AT g Students could use gel electrophoresis to produce ‘fingerprints’ of food dyes. Students should be able to: interpret data provided from investigations into gene expression Evaluate appropriate data for the relative influences of genetic and environmental factors on phenotype. REQUIRED PRACTICAL 10- Investigation into the effect of an environmental variable on the movement of an animal using either a choice chamber or a maze. REQUIRED PRACTICAL 11: Production of a dilution series of a glucose solution and use of colorimetric techniques to produce a calibration curve with which to identify the concentration of glucose in an unknown ‘urine’ sample. After finishing this topic, students will gain the following skills- Using a colorimeter to record quantitative measurements. Using laboratory glassware apparatus to make up serial dilutions. Safely and ethically using organisms to measure animal responses. Skills- AT h Students could design and carry out investigations into the effects of indole acetic acid on root growth in seedlings. Students could design and carry out investigations into: the sensitivity of temperature receptors in human skin habituation of touch receptors in human skin Resolution of touch receptors in human skin. Students could design and carry out an investigation into the effect of a named variable on human pulse rate. Students could use values of heart rate (R) and stroke volume (V) to calculate cardiac output (CO), using the formula AT b – use a colorimeter to record quantitative measurements AT c – use glassware to produce serial dilutions AT d Students could examine prepared slides of skeletal muscle using an optical microscope. AT h Students could investigate the effect of repeated muscular contraction on the rate of muscle fatigue in human volunteers.
Knowledge	Producing DNA fragments, in vivo and in vitro cloning, genetic screening, genetic fingerprinting Knowledge- survival and response, plant growth factors, A reflex arc, receptors, control of heart rate
Rationale	Studying human DNA and genetics can help scientists better understand where humans came from as a species. It can help elucidate the connections between different groups of people and give historians and anthropologists a clearer picture of historic human migration patterns. The recombinant technology is important because it enables the creation of multiple copies of genes and the insertion of foreign genes into other organisms to give them new traits, such as antibiotic resistance or a new colour. Recombinant DNA technology has been effectively used to produce various human proteins in microorganisms, such as insulin and growth hormone, used in the treatment of diseases. Gene therapy aims to treat/cure/prevent disease by replacing a defective gene with a normal one using recombinant DNA technology. Most human clinical trials in gene therapy are still in the research stage with only over 400 trials conducted in about 3000 patients in order to treat for single gene disorders, cancers, and AIDS. Scientists agree that this is the most powerful application of rDNA technology, but have been cautious in its application due to associated risks There is certain knowledge from GCSE that will prove beneficial to the understanding of this section such as reflex arc and receptors. This section explains how multicellular organisms respond to the stimuli and gives a clear picture of both nervous and hormonal coordination. Students can also relate the knowledge of homeostasis to the diseases such as Diabetes. IT also explains how each type of response increases an organism’s chances of survival.

knowledge organisers

A knowledge organiser is an important document that lists the important facts that learners should know by the end of a unit of work. It is important that learners can recall these facts easily, so that when they are answering challenging questions in their assessments and GCSE and A-Level exams, they are not wasting precious time in exams focusing on remembering simple facts, but making complex arguments, and calculations.

We encourage all pupils to use them by doing the following:

Quiz themselves at home, using the read, write, cover, check method.
Practise spelling key vocabulary
Further researching people, events and processes most relevant to the unit.