Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.12 -Understand the biological consequences of pollution of air by sulfur dioxide and carbon monoxide. Specification Point 4.13 - Understand that water vapour, carbon dioxide, nitrous oxide, methane and CFCs are greenhouse gases. Specification Point 4.14 - Understand how human activities contribute to greenhouse gases. Specification Point 4.15- Understand how an increase in greenhouse gases results in an enhanced greenhouse effect and that this may lead to global warming and its consequences. Specification Point 4.16 - Understand the biological consequences of pollution of water by sewage. Specification Point 4.17 - Understand the biological consequences of eutrophication caused by leached minerals from fertilizer. Complete set of Chapter 6 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.11B - Describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and denitrifying bacteria. Complete set of Chapter 6 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.10 - Describe the stages in the carbon cycle, including respiration, photosynthesis, decomposition and combustion. Complete set of Chapter 6 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.6 - Understand the names given to different trophic levels, including producers, primary, secondary and tertiary consumers and decomposers. Specification Point 4.7 - Understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer. Specification Point 4.8 - Understand the transfer of substances and energy along a food chain. Specification Point 4.9 - Understand why only about 10% of energy is transferred from one trophic level to the next. Complete set of Chapter 6 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.38 - Explain Darwin’s theory of evolution by natural selection. Specification Point 3.39 - Understand how resistance to antibiotics can increase in bacterial populations, and appreciate how such an increase can lead to infections being difficult to control. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.35B - Understand how a change in DNA can affect the phenotype by altering the sequence of amino acids in a protein. Specification Point 3.36B - Understand how most genetic mutations have no effect on the phenotype, some have a small effect and rarely do they have a significant effect. Specification Point 3.37B - Understand that the incidence of mutations can be increased by exposure to ionising radiation (for example, gamma rays, x-rays and ultraviolet rays) and some chemical mutagens (for example, chemicals in tobacco). Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.31 - Understand how random fertilization produces genetic variation of offspring. Specification Point 3.32 - Know that in human cells the diploid number of chromosomes is 46 and the haploid number is 23. Specification Point 3.33 - Understand that variation within a species can be genetic, environmental, or a combination of both. Specification Point 3.34 - Understand that mutation is a rare, random change in genetic material that can be inherited. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.28 - Understand how division of a diploid cell by mitosis produces two cells that contain identical sets of chromosomes. Specification Point 3.29 - Understand that mitosis occurs during growth, repair, cloning and asexual reproduction. Specification Point 3.30 - Understand how division of a cell by meiosis produces four cells, each with half the number of chromosomes, and that this results in the formation of genetically different haploid gametes. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.19 - Understand how genes exist in alternative forms called alleles which give rise to differences in inherited characteristics. Specification Point 3.20 - Understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, and genotype. Specification Point 3.21B - Understand the meaning of the term codominance. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.16B - Describe a DNA molecule as two strands coiled to form a double helix, the strands being linked by a series of paired bases: adenine (A) with thymine (T), and cytosine © with guanine (G). Specification Point 3.17B - Understand that an RNA molecule is single stranded and contains uracil (U) instead of thymine (T). Specification Point 3.18B - Describe the stages of protein synthesis including transcription and translation, including the role of mRNA, ribosomes, tRNA, codons and anticodons. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.11 - Describe the role of the placenta in the nutrition of the developing embryo. Specification Point 3.12 - Understand how the developing embryo is protected by amniotic fluid. Specification Point 3.13 - Understand the roles of oestrogen and testosterone in the development of secondary sexual characteristics. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.8 - Understand how the structure of the male and female reproductive systems are adapted for their functions. Specification Point 3.9 - Understand the roles of oestrogen and progesterone in the menstrual cycle. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.1 - Understand the differences between sexual and asexual reproduction. Specification Point 3.2 - Understand that fertilization involves the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.95B - Understand the sources, roles and effects of the following hormones: ADH, FSH and LH. Complete set of Chapter 4 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.94 - Understand the sources, roles and effects of the following hormones: adrenaline, insulin, testosterone, progesterone and oestrogen. Complete set of Chapter 4 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.93 - Describe the role of the skin in temperature regulation, with reference to sweating, vasoconstriction and vasodilation. Complete set of Chapter 4 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.90 - Describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object. Specification Point 2.91 - Describe the structure and function of the eye as a receptor. Specification Point 2.92 - Understand the function of the eye in focusing on near and distant objects, and in responding to changes in light intensity. Complete set of Chapter 4 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.83 - Understand that plants respond to stimuli. Specification Point 2.84 - Describe the geotropic and phototropic responses of roots and stems. Specification Point 2.85 - Understand the role of auxin in the phototropic response of stems. Complete set of Chapter 4 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.80 - Understand how organisms are able to respond to changes in their environment. Specification Point 2.81 - Understand that homeostasis is the maintenance of a constant internal environment, and that body water content and body temperature are both examples of homeostasis. Specification Point 2.82 - Understand that a coordinated response requires a stimulus, a receptor and an effector. Complete set of Chapter 4 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.72B - Understand how the kidney carries out its roles of excretion and osmoregulation. Specification Point 2.73B - Describe the structure of the urinary system, including the kidneys, ureters, bladder and urethra. Specification Point 2.74B - Describe the structure of a nephron, including the Bowman’s capsule and glomerulus, convoluted tubules, loop of Henle and collecting duct. Complete set of Chapter 4 Lectures are available.