Classification – process by which living things are placed into groups depending on their structure & characteristics in a system Linnean system (Carl Linnaeus) Linnean system – Dear Kate Please Come Over For Great Spagetti) Describe the impact of developments in...
6.3.1 Theory of evolution (biology only) See 6.2.2 Evolution 6.3.2 Speciation (biology only) Speciation Populations become extremely varied & no interbreed anymore Formation of new species (a group of organisms able to interbreed & produce fertile offspring)...
Variation - differences in the characteristics of individuals in a population Cause of variation genes they have inherited (genetic causes) conditions in which they have developed (environmental causes) combination of genes and the environment See topics below for...
6.1.1 Sexual and asexual reproduction 6.1.3 Advantages and disadvantages of sexual and asexual reproduction (biology only) Sexual reproduction (meiosis) Joining of male & female gametes that produce genetically different offspring Gametes formed by...
5.4.1 Control and coordination Where is the plant hormone made? In the root tip Which hormone and how does it control the responses of plants to light and gravity? Auxin Unequal distributions of auxin cause unequal growth rates in plant roots & shoots Higher con...
5.3.1 Human endocrine system Endocrine system Composed of gland which secrete chemicals called hormones into bloodstream Hormone transported in bloodstream to target organ where it produces an effect Effect slower but longer compare to nervous system What is a...
5.2.1 Structure and function Central nervous system (CNS) Brain & spinal cord Coordinates response of effectors eg muscles contracting / glands secreting hormones Stimulus → receptor → coordinator (CNS) → effector → response Describe the function of receptors. (2)...
What is homeostasis? Regulation of internal conditions of a cell or organism to maintain optimal conditions Why is homeostasis important in body? (1) Maintain optimal conditions for enzymes action & all cell functions In human body, these include control of: Blood...
4.1.1 Photosynthetic reaction Photosynthesis An endothermic reaction in which energy comes from sunlight is transferred from environment to the chloroplasts by light Equation Adaptations of leaves Large surface area - absorb light Thin walls - short diffusion distance...
4.2.1 Aerobic and anaerobic respiration Cellular respiration An exothermic reaction which is continuously occurring in living cells Organisms need energy for Chemical reactions to build larger molecules Movement Keeping warm As oxidation of glucose is incomplete in...
3.2.1 Producing monoclonal antibodies Monoclonal antibodies Produced from single clone of cells Specific to one binding site on an antigen Target specific chemical / cell in body Production of monoclonal antibodies Vaccinate mouse to stimulate mouse lymphocytes to...
3.3.1 Detection and identification of plant diseases Plants infected by viral, bacterial, fungal & insects (eg aphids) Aphids Sharp mouthparts – penetrate into phloem vessels for phloem sap Attack in huge no. – deprive plant cells – damage & weaken plant Act...
3.1.1 Communicable (infectious) diseases Pathogens Microorganisms that cause communicable diseases Eg bacteria, viruses, protists, fungi How cause? Bacteria Produce toxins - damage tissues - ill Reproduce rapidly in binary fusion Viruses Live & reproduce...
2.3.1 Plant tissues Waxy cuticle Reduce water loss by evaporation So it doesn't wilt Upper epidermis Cover the leaf Root hair cell Adapt to absorb water by osmosis & mineral ions by active transport from soil efficiently Palisade mesophyll Chloroplast - absorb...
2.2.1 The human digestive system Balanced diet - right amount of nutrients & energy for needs What is the function of digestive system? An organ system in which several organs work tgt to digest & absorb food Mouth How can mouth break down starchy foods? Teeth...
1.3.1 Diffusion Spreading out of particles of any substance in solution, or particles of a gas, causing a net movement from an area of higher concentration to an area of lower concentration What substances in animals & plants are transported in & out of cells...
Cells → tissues → organs → organ system → organism Cells - basic structural & functional units of living organisms Muscular Contracts to move things attached to it In stomach, contracts to move food Glandular Contains secretory cells Produce & release...
Chromosomes What does the nucleus contain? Chromosomes made of DNA molecules Each chromosome carries a large no of genes Why do most organisms have an even number of chromosomes in body cells? In body cells, chromosomes are normally found in pairs 1.2.2 Mitosis and...
1.1.1 Eukaryotes and prokaryotes Eukaryotic cell Animal, plant, fungi Has a cell membrane, cytoplasm & genetic material enclosed in a nucleus More complex 1.1.2 Animal and plant cells Animal cell Nucleus Contains genetic material (DNA) Control cell's activities...
Heart attacks: Blood supply is suddenly blocked from getting to the heart Coronary heart disease is the leading cause of heart attacks Blood supply is trapped by fatty substances in the coronary arteries When a plaques ruptures it causes a blood clot Can also block...
Organs: Stems Roots Leaves Tissues: Epidermal Meristem Xylem and phloem Palisade mesophyll Spongy mesophyll Leaves contain epidermal, mesophyll, xylem and phloem Phloem: translocation Made of columns of elongated cells with pores in the end walls to let cell sap...
Actual object size = Image size/magnification I=AxM Practical: 1. prepare your slide - add drop of water, specimen, iodine then coverslip 2. clip slide onto stage, select lowest power objective lens, use coarse adjustment knob, adjust focus with fine adjustment knob...
Cells differentiate to become specialized - become specialized for the job Develop different subcellular structures to be able to carry out specific functions In most animal cells, the ability to differentiate is lost at an early stage, after they become...
Flowering plants have two separate transport systems Xylem and phloem Xylem tissues transport water and mineral ions from roots to stem, leaves and flowers Phloem cells carry dissolved sugars from the leaves to the rest of the plant (including growing regions and...
Cells are grouped into tissues and tissues are grouped into organs. Pulmonary artery – carries deoxygenated blood from heart to lungs Vena cava – brings deoxygenated blood from body to heart Aorta – carries oxygenated blood from heart to body Pulmonary vein – carries...
Veins carry deoxygenated blood from the body to the heart. They have wide passages because the blood flows slowly under low pressure. Arteries carry oxygenated blood from heart to the body. The blood has to be under high pressure, so they have strong, thick...
Mouth: How food enters the body Chewing breaks up food and mixes it with enzymes to start digestion Oesophagus: Carries food from mouth to stomach by peristalsis Peristalsis is the contraction and relaxation of muscles which pushes the food down ...
Osmosis – diffusion of water molecules Osmosis is the diffusion of molecules from a high to a low concentration across a partially permeable membrane. It is a special case of diffusion, the diffusion of water. Partially permeable – only lets in certain...
Substances move from an area of LOW concentration to an area of high concentration across a permeable membrane Across a concentration gradient so requires energy from mitochondria Root hair cells: Plants need mineral ions for healthy growth The concentration of...
Evaporation and diffusion of water from a plants surface (leaves) Evaporation creates a slight shortage of water so more is drawn up from the roots through the xylem cells to replace it Called transpiration stream A side-effect of how leaves are adapted for...
Growth is a permanent increase in size, length, mass and cell number. Percentile charts can help to show if your child is growing faster or slower than is normal for their age. The 50th percentile is the median. If your height is at the 50th percentile, you...
Growth in plants: · Grow through all their lives · Meristems are a place where cells keep dividing · Once cells have divided, they get longer (elongate) · Meristem can specialise/differentiate Growth in animals: · Stop...
Plasma: Liquid part of the blood Carries the blood cells through the blood vessels Contains many dissolved substances such as carbon dioxide and glucose White blood cells: Larger than red blood cells Have a nucleus Some surround and destroy pathogens Some...
Enzymes are biological catalysts. They are found in living organisms and a catalyst changes the rate of a reaction but remains unchanged at the end of the reaction. Each enzyme is specific for its substrate, which means that it only works with that substrate. ...
Respiration is the process of releasing energy Aerobic respiration uses oxygen from the air to release energy from glucose Happens in every single cell A chemical reaction Glucose + oxygen à carbon dioxide + water + energy Diffusion: Is the movement of particles from...
− The release of energy from glucose without using oxygen. − Glucose à lactic acid + energy Advantages: · Useful for when oxygen cannot be delivered fast enough Disadvantages: · Releases less energy than aerobic respiration · ...
One villus / many villi. The large capillary network carries absorbed molcules away quickly, maintaining a steep concentration gradient for diffusion. Millions of villi means an increased surface area. The surface is formed from a single layer of cells making...
Low temperature, dim light and low carbon dioxide levels all limit the rate of photosynthesis. We can measure these by measuring the rate pondweed gives off oxygen. This can test the effect of: · Temperature, using hot and cold water baths · ...
Water and substances dissolved in the water are transported around plants in veins. Veins contains vessels called xylem and phloem. Xylem: Carries water and dissolved mineral ions up to the leaves Phloem: Sucrose is dissolved in water and carried up...
Embryonic stem cells: Cells in an embryo are unspecialized They divide to produce the differentiated cells in the body (differentiated = specialised) Adult stem cells: Are found in differentiated tissue, such as bone or skin They divide to repair damaged cells...
No nucleus Chromosomal DNA – carries most of the genes Some have extra circles of plasmid DNA containing additional genes Cell membrane Some have flagellum to help them move Many have a cell wall for protection, but this is made out of a different substance to plant...
Prokaryotes are single celled organisms. Eukaryotes are complex, animal and plant cells. Eukaryotes are made of eukaryotic cells. Prokaryotes: Cell wall, cell membrane, cytoplasm Small rings of DNA called plasmids No chloroplasts or mitochondria Bacterial cells...
In mitosis a cell splits to create 2 identical copies, for growth and repair. The daughter cells are diploid (2 sets of chromosomes). The chromosomes line up, get pulled apart and the cytoplasm closes around them. The chromosomes have to replace themselves first....
Animal cell: Cell membrane – controls what enters and leaves the cell, e.g. oxygen, carbon dioxide, glucose Nucleus – contains DNA, instructions for the cell Cytoplasm – fills the cell, reactions take place here Mitochondria – where respiration takes place, releasing...
Fuels from fermentation In India only animal waste is fed in (there are taboos against using human waste), this produces high quality gas but little amounts of fertiliser. Biogas can be produced on a large scale, or on a small scale. For example, a small biogas...
The kidneys Our bodies need to get rid of waste products. Three waste products our bodies must excrete are CO2, urea and sweat. This is known as homeostasis (controlling conditions inside the body). Liver Urea (a waste product from the breakdown of amino acids)...
B2.7 Cell Division and inheritance Summary Characteristics are passed on from one generation to the next in both plants and animals. Simple genetic diagrams can be used to show this. There are ethical considerations in treating genetic disorders. Genetic material In...
B2.8 Speciation Summary Changes in the environment of plants and animals may cause them to die out. The fossil record shows that new organisms arise, flourish, and after a time become extinct. The record also shows changes that lead to the formation of new species....
Diffusion Materials like oxygen, carbon dioxide and glucose enter and leave cells by diffusion. Diffusion occurs when particles spread. They move from a region where they are in high concentration to a region where they are in low concentration. Diffusion happens when...
B2.6 Respiration Summary Respiration in cells can take place aerobically or anaerobically. The energy released is used in a variety of ways. The human body needs to react to the increased demand for energy during exercise. Respiration Definition: The process of...
B2.5 Proteins Summary Proteins have many functions, both inside and outside the cells of living organisms. Proteins, as enzymes, are now used widely in the home and in industry. Protein structure Protein molecules are made up of long chains of amino acids. ...
B2.4 Organisms and their environment Summary Living organisms form communities, and we need to understand the relationships within and between these communities. These relationships are affected by external influences. Physical factors Physical factors that may affect...
B2.3 Photosynthesis Summary Green plants and algae use light energy to make their own food. They obtain the raw materials they need to make this food from the air and the soil. The conditions in which plants are grown can be changed to promote growth....
B2.1 Cells and Cell Structures Summary All living things are made up of cells. The structures of different types of cells are related to their functions. To get into or out of cells, dissolved substances have to cross the cell membranes. Cells...
B2.1 Tissues, Organs and Organ Systems Summary The cells of multicellular organisms may differentiate and become adapted for specific functions. Tissues are aggregations of similar cells; organs are aggregations of tissues performing specific...
B1.8 Evolution Summary Particular genes or accidental changes in the genes of plants or animals may give them characteristics which enable them to survive better. Over time this may result in entirely new species. There are different theories of evolution. Darwin’s...
B1.7 Genetic Variation and Its Control Summary There are not only differences between different species of plants and animals but also between individuals of the same species. These differences are due partly to the information in the cells they have inherited from...
B1.4 Interdependence and Adaptation Summary Organisms are well adapted to survive in their normal environment. Population size depends on a variety of factors including competition, predation, disease and human influences. Changes in the environment may affect the...
B1.5 Energy and biomass in food chains Summary By observing the numbers and sizes of the organisms in food chains we can find out what happens to energy and biomass as it passes along the food chain. Energy transfer Radiation from the Sun is the source of energy for...
B1.6 Waste materials from plants and animals Summary Many trees shed their leaves each year and most animals produce droppings at least once a day. All plants and animals eventually die. Microorganisms play an important part in decomposing this material so that it can...
B1.2 Nerves and Hormones Summary The nervous system and hormones enable us to respond to external changes. They also help us to control conditions inside our bodies. Hormones are used in some forms of contraception and in fertility treatments. Plants also produce...
B1.3 The Use and Abuse of Drugs Summary Drugs affect our body chemistry. Medical drugs are developed and tested before being used to relieve illness or disease. Drugs may also be used recreationally as people like the effect on the body. Some drugs are...
B 1.1.2 Infectious Disease Summary Our bodies provide an excellent environment for many microbes which can make us ill once they are inside us. Our bodies need to stop most microbes getting in and deal with any microbes which do get in. Vaccination can be used to...
B1.1.1 Diet and Exercise Summary A combination of a balanced diet and regular exercise is needed to help keep the body healthy. Healthy Diet A healthy diet contains the right balance of the different foods you need and the right amount of energy. These foods should...