Human+Biology+2A

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** UNIT 2AHBS ** = ** Unit description ** =

The focus for this unit is **functioning humans.** This unit looks at how human structure and function supports cellular metabolism and how lifestyle choices impact body functioning. The environment in which cells operate is dynamic to cater for the changing needs of cellular activities. Cells contain structures that carry out a range of functions related to metabolism, including anabolic and catabolic reactions. Materials are exchanged in a variety of ways within and between the internal and external environment to supply inputs and remove outputs of metabolism. Metabolic activity requires the presence of enzymes to meet the needs of cells and the whole body. The respiratory, circulatory, digestive and excretory systems control the exchange and transport of materials in support of metabolism, particularly cellular respiration. The body systems have a range of non-specific internal and external defences against pathogens that disrupt body functions. Each system has specific characteristics that suit it to its particular function and to protect against invaders. These defence mechanisms can be assisted by the use of medical preparations and good hygiene practices. Cells that are damaged by pathogens or in the normal course of body activity are replaced. Mitosis replaces cells but also adds more cells causing the person to grow in size and complexity. Lifestyle choices can have serious effects on body functioning that may take years to become apparent. Variations between individuals may determine the progression and diagnosis of the disease. The cellular mechanisms for gamete production and zygote formation contribute to human diversity. Meiosis and fertilisation are important in producing new genetic combinations. Students investigate personal questions about problems associated with factors affecting metabolism. They trial different methods of collecting data, use simple calculations to analyse data and become aware of the implications of bias and experimental error in the interpretation of results. They are encouraged to use ICT to interpret, communicate their findings in a variety of ways.

** Unit content ** This unit includes knowledge, understandings and skills to the degree of complexity described below:

** Human form and function **
** Cells, metabolism and regulation ** Metabolic reactions make energy and matter available for use in cells. These reactions are controlled by enzymes which are affected by various factors. Cellular structures provide for exchange of materials, metabolism and cell division (mitosis and meiosis). Efficient functioning of the body requires non-specific protection. Non-specific protection includes internal and external methods. Metabolism: · anabolic and catabolic reactions and organelles involved · respiration (aerobic and anaerobic); inputs, outputs and organelles involved · ATP and cellular uses of energy · nutrients required and their uses including carbohydrates/simple sugars, proteins/amino acids, lipids/fatty acids and glycerols, vitamins and minerals · enzyme function including reduction in activation energy, lock and key principle · factors that affect enzyme activity including pH, temperature, cofactors, co-enzymes. Transport: · structure of the cell membrane as it relates to transport of materials (greater detail covered in Unit 3A) · methods of transporting materials including diffusion, facilitated diffusion, osmosis, active transport, endocytosis and exocytosis · factors affecting exchange of materials including SA/Vol ratio, concentration gradients. Mitosis: · stages of mitosis · function and significance of chromosome number in mitosis. ** Body systems ** The respiratory, circulatory, digestive and excretory systems are specialised to control inputs and outputs in supporting metabolism. · Respiratory system § gas exchange including characteristics of respiratory surfaces § maintenance of concentration gradients in lungs including breathing and blood flow. · Circulatory system § role of the heart, cardiac cycle, arteries, veins and capillaries in the circulation of blood § roles of plasma and erythrocytes in the transport of materials including oxygen, nutrients and wastes § clotting of blood at wound including fibrinogen and platelets § inflammatory response § lymphatics and white blood cells (overview only). · Digestive system § mechanical digestion including teeth, bile, process of peristalsis § chemical digestion of carbohydrates, lipids and proteins including enzymes and the associated glands § absorption of nutrients § elimination. · Excretory system § the nephron § formation of urine and excretion of wastes by the urinary system § deamination of amino acids in the liver. · Protection of body systems § body's external defences against disease—of skin, digestive, urogenital, respiratory, eye and ear. · Assisted protection of the body: § external including hygiene, topical preparations and barriers § internal including antibiotics and antivirals.

** Human diversity and change **
** Inheritance ** Gametes are formed as a result of meiosis. Meiosis: · stages of meiosis · function and significance of chromosome changes in meiosis · compare mitosis and meiosis. ** Variation and evolution ** New genetic combinations are made as a result of meiosis and fertilisation, giving rise to unexpected variations. Variation from meiosis: · crossing over · random assortment · non-disjunction. Variation from fertilisation: · random fertilisation. ** The practice of human biology ** ** Approaches to investigating and communicating human biology ** · plan and conduct a safe investigation on a question of choice developed from a given contextual problem · use a prescribed format and trial a range of techniques to collect data · collect valid and reliable data · analyse data using rates, percentages and frequencies · refer to possible bias and experimental error · use scientific terminology and appropriate abstract concepts in discussions. ** The relevance of human biology to everyday life ** Lifestyle choices can compromise body functioning in the short-term and affect future health. Individual differences influence the technologies used to inform the diagnoses of different medical conditions. Lifestyle choices that compromise health: · active or sedentary lifestyle · personal hygiene · use of drugs including performance enhancing drugs, alcohol and smoking · diet. Individual differences: · diagnosis depends upon individual differences in body form, stature and disease progression.