Biology 2020 October / November

Characteristics of Living Organisms

The seven characteristics of life (MRS GREN): movement, respiration, sensitivity, growth, reproduction, excretion, nutrition.

Variety of Living Organisms

Classification into five kingdoms (animals, plants, fungi, bacteria, protists); features of viruses; dichotomous keys.

Cell Structure and Organisation

Animal and plant cells; cell organelles (nucleus, mitochondria, chloroplast, cell wall, vacuole); cell, tissue, organ, system hierarchy; specialised cells.

Biological Molecules

Structure and function of carbohydrates, lipids, proteins and DNA; enzyme structure; food tests (Benedict's, iodine, biuret).

Movement of Substances

Diffusion, osmosis and active transport; factors affecting diffusion; water potential; turgid and plasmolysed cells.

Nutrition in Plants

Photosynthesis equation and process; limiting factors (light, CO₂, temperature); leaf structure; mineral ion requirements.

Nutrition in Humans

Balanced diet; digestive system; enzymes (amylase, protease, lipase); absorption in small intestine; villi; liver functions.

Respiration

Aerobic and anaerobic respiration equations; ATP; fermentation; effects of exercise; mitochondria.

Gas Exchange

Gas exchange in humans (alveoli, lungs); gas exchange in plants (stomata, guard cells); gas exchange in fish (gills).

Transport in Plants

Xylem and phloem; transpiration; transpiration stream; factors affecting transpiration rate; translocation.

Transport in Humans

Heart structure and function; circulatory system; blood composition (plasma, red cells, white cells, platelets); blood groups; coronary heart disease.

Excretion

Kidneys and urine formation; ultrafiltration and reabsorption; role of ADH; liver producing urea; lungs excreting CO₂.

Coordination and Response

Nervous system (neurones, reflex arc, brain, spinal cord); hormonal system (hormones, endocrine glands); plant responses (tropisms, auxins).

Homeostasis

Regulation of body temperature; blood glucose control (insulin, glucagon); ADH and water balance; negative feedback.

Reproduction in Plants

Sexual reproduction (flowers, pollination, fertilisation, seed dispersal); asexual reproduction (runners, tubers, bulbs, cuttings).

Reproduction in Humans

Male and female reproductive systems; menstrual cycle; fertilisation; pregnancy; contraception; sexually transmitted infections.

Cell Division

Mitosis (growth and repair, produces 2 identical diploid cells); meiosis (produces 4 haploid gametes, genetic variation).

Inheritance

DNA structure; genes and alleles; dominant and recessive; Punnett squares; monohybrid and dihybrid crosses; codominance; sex linkage; mutations.

Natural Selection and Evolution

Natural selection; Darwin's theory; variation; adaptation; antibiotic resistance; speciation; fossil record.

Organisms and Their Environment

Ecosystems; habitats and niches; abiotic and biotic factors; population size; sampling techniques (quadrats, transects).

Feeding Relationships

Food chains and food webs; producers, consumers and decomposers; energy transfer; trophic levels; pyramids of number, biomass and energy.

Nutrient Cycles

Carbon cycle (photosynthesis, respiration, decomposition, combustion); nitrogen cycle (fixation, nitrification, denitrification); water cycle.

Human Influences on the Environment

Pollution (water, air, land); deforestation; habitat destruction; climate change; conservation; biodiversity; eutrophication.

Food Production

Crop plants (pest control, fertilisers, irrigation); livestock farming; fish farming; glasshouses and hydroponics; food chains and efficiency.

Selective Breeding

Artificial selection in plants and animals; examples (high-yield crops, disease-resistant varieties, dog breeds); advantages and risks.

Genetic Engineering

Process of genetic modification; GM crops (pest resistance, herbicide tolerance); production of insulin and other proteins; ethical issues.

Cloning

Tissue culture; embryo transplanting; adult cell cloning (Dolly the sheep); stem cells; advantages and ethical considerations.