Russia 9 класс Biology (advanced)

1. Introduction

Sciences about humans

• Sciences About Humans: Anatomy, Physiology and Hygiene – Anatomy studies how the body is built, physiology studies how it works, and hygiene studies how to stay healthy. Scientists use observation, measurement and experiments. Doctors, surgeons, physiologists, sports scientists and nutritionists all use these sciences.

2. Cells and tissues

Biomolecules and cells

• Biomolecules – A cell is mostly water, plus four big families of carbon compounds: proteins, carbohydrates, lipids and nucleic acids. Grinding tissue in acid separates small molecules (acid-soluble pool) from big ones – proteins, polysaccharides and nucleic acids (acid-insoluble pool). Proteins are chains of amino acids folded into four levels of structure. Polysaccharides are chains of sugars; lipids are fatty acids on glycerol; nucleic acids are chains of nucleotides. Enzymes are protein catalysts that bind a substrate at the active site, lower the activation energy, and are affected by temperature, pH, substrate level and inhibitors.

3. Nervous system

Nervous system

• Nervous System, Reflex Action and the Human Brain – Nerve cells (neurons) carry messages as electric impulses and pass them to the next cell with chemicals across a gap called a synapse. Quick safety responses (reflexes) are handled by the spinal cord; thinking and control come from the brain, which is guarded by the skull and a fluid cushion.

4. Sensory systems

Receptors and senses

• Sense Organs – Sense organs let us pick up changes around us (stimuli). The eye senses light, the ear sound and balance, the nose smell, the tongue taste, and the skin touch, pressure, heat, cold and pain. Each has receptor cells that turn the stimulus into nerve signals. The signal goes along a sensory nerve to the brain or spinal cord, which sends an order to a muscle: the response.

5. Endocrine system

Hormones

• Hormones in Animals: Endocrine Glands and Feedback – Endocrine glands release chemical messengers called hormones straight into the blood. The blood carries them all over the body, but they act only on target cells. Hormones control growth, metabolism, emergency response, blood sugar and puberty, and their amount is kept right by feedback.

6. Behaviour

Reflexes and learning

Coming soon

7. Musculoskeletal system

Bones and muscles

• The Skeletal System – The skeleton is the body's frame of 206 bones (adult). It has five main jobs: support and shape, protection, movement (with muscles), making blood cells in red marrow, and storing minerals like calcium. Bones meet at joints; hinge joints (elbow, knee) bend one way, ball-and-socket joints (shoulder, hip) move in all directions. Ligaments join bone to bone, tendons join muscle to bone, cartilage cushions the ends. Muscles only pull, so they work in antagonistic pairs such as biceps and triceps.

8. Circulatory and lymphatic systems

Heart, vessels, blood

• Transportation in Humans: Heart, Blood Vessels, Blood and Lymph – The heart is a four-chambered muscular pump. Blood passes through it twice in one full round: once to the lungs to pick up oxygen, and once to the rest of the body. This is double circulation. Arteries carry blood away from the heart, veins bring it back and capillaries do the exchange. Blood (plasma, RBCs, WBCs, platelets) and lymph together carry food, gases, hormones and wastes.

9. Immune system

Immunity

• The Immune System: How Your Body Fights Germs – Germs (pathogens) cause infectious disease. The body has three lines of defence: barriers (skin, mucus, acid), a fast general (innate) response (inflammation, fever, phagocytes) and a slow, specific (adaptive) response (B cells make antibodies, T cells kill infected cells). Memory cells make the second attack fast. Vaccines create memory safely. Immunity can go wrong: allergy, autoimmune disease, immunodeficiency (e.g. HIV).

10. Respiratory system

Respiration

• Respiration: Aerobic, Anaerobic and the Human Lungs – Respiration is the breakdown of food, usually glucose, inside cells to release energy, stored as ATP. With oxygen (aerobic) glucose is fully broken into carbon dioxide and water and gives much energy; without oxygen (anaerobic) it gives little energy and makes ethanol (yeast) or lactic acid (muscles). Our lungs bring oxygen to the blood through millions of alveoli.

11. Digestive system

Digestion

• Human Digestive System and Heterotrophic Nutrition – Heterotrophs take ready-made food from other living things. Humans are holozoic: we eat whole food and break it down in a long tube, the alimentary canal. Teeth, saliva, stomach acid, enzymes, bile and pancreatic juice cut big food molecules into small ones that villi in the small intestine absorb into blood.

12. Excretory system

Kidneys

• Excretion in Humans and Plants: Kidneys, Nephrons and More – Excretion is the removal of harmful nitrogen wastes made in the body. Two kidneys filter blood through about a million nephrons each: the glomerulus filters, the tubule takes back useful glucose, amino acids, salts and water, and the leftover urea and extra water become urine. Plants remove waste through stomata, falling leaves, bark, resins and gums.

13. Reproductive system

Reproduction

• Reproduction in Human Beings and Reproductive Health – At puberty, hormones from the brain make the testes and ovaries start working. The male system makes and carries sperm; the female system makes eggs and provides a place (uterus) where a baby develops. Fertilisation happens in the oviduct, and the embryo is fed through the placenta. Reproductive health includes safe choices, contraception, avoiding female foeticide, and preventing sexually transmitted diseases such as HIV/AIDS.

14. Skin

Skin

• Human Skin: Layers, Jobs and Sun Safety – Skin is the largest organ of the body. It has three layers: the epidermis (outer, waterproof, holds melanin), the dermis (blood vessels, nerves, glands, hair roots) and a fat layer underneath. It protects, senses touch and pain, controls body temperature with sweat and blood flow, and makes vitamin D in sunlight. Too much UV light harms skin cells, speeds ageing and can cause skin cancer such as melanoma.

15. Adaptations of the human body

Adaptations

Coming soon

16. Human genetics

Genetics

• Heredity and Mendel's Laws – Heredity is the passing of traits from parents to children through genes. Each parent gives one copy of every gene. A dominant copy hides a recessive one, which is why Mendel saw 3:1 in a monohybrid cross and 9:3:3:1 in a dihybrid cross. Genes are pieces of DNA that make proteins, and proteins build the trait.

17. Anthropogenesis

Human evolution

• Evolution: Origin of Life, Mechanisms and Human Evolution – Life began on the early Earth from simple chemicals: Oparin and Haldane proposed it and Miller made amino acids in a flask. Evidence of evolution comes from fossils, homologous and analogous organs, embryos, molecules and changes we can watch (industrial melanism, drug resistance). Darwin explained it by natural selection acting on variation in populations; the modern synthetic theory adds genes: mutation, recombination, gene flow, genetic drift and natural selection change allele frequencies. If none of these act, frequencies stay constant: Hardy–Weinberg, p² + 2pq + q² = 1. Selection can be stabilising, directional or disruptive. One ancestor spreading into many habitats gives adaptive radiation (Darwin’s finches, Australian marsupials). Humans evolved from Dryopithecus-like apes through Australopithecus, Homo habilis, Homo erectus and Neanderthals to Homo sapiens.