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Requirements of living things. Cells exchange matter and energy In: Oxygen Nutrients eg glucose Water Ions Out: Carbon dioxide Wastes eg urea Water Ions.

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Presentation on theme: "Requirements of living things. Cells exchange matter and energy In: Oxygen Nutrients eg glucose Water Ions Out: Carbon dioxide Wastes eg urea Water Ions."— Presentation transcript:

1 Requirements of living things

2 Cells exchange matter and energy In: Oxygen Nutrients eg glucose Water Ions Out: Carbon dioxide Wastes eg urea Water Ions Heat energy Processes: Respiration Synthesis Growth Division

3 Cells need energy Energy in the cell is transported as ATP Cells can get energy by: Respiration (all cells) - this takes place mainly in the mitochondria Glucose + Oxygen  Water + Carbon dioxide + Energy (ATP & heat) Photosynthesis (plants)- this takes place in the chloroplasts light energy Water + Carbon dioxide  Oxygen + glucose chlorophyll Energy is used for all the cell’s activities – movement, active transport, synthesis, growth, division, nerve impulses, etc

4 Summary of respiration

5 Fermentation In plants and fungi: Pyruvate (pyruvic acid) is converted to ethanol (alcohol) and carbon dioxide If there is not enough oxygen, organisms can make energy by anaerobic respiration or fermentation. This takes place in the cytoplasm of cells. In animals: Pyruvate (pyruvic acid) is converted to lactic acid

6 Summary of photosynthesis

7 ATP and ADP Act as chemical batteries Carry and release small amounts of energy ATP is the ‘charged battery’ and ADP is the ‘flat battery’ energy adenosine phosphate adenosine ATP ADP

8 Cells need matter Nutrients and essential materials include: Organic compounds (contain Carbon) eg glucose, proteins, fats, DNA, RNA, ATP used for body structures, cell components, enzymes, hormones, etc Inorganic elements or compounds eg nitrogen, phosphorus, calcium, iron, sodium, potassium, etc used for making organic compounds (eg proteins, DNA & ATP contain nitrogen and phosphorus), maintaining osmotic balance, and pH balance Gases (oxygen and carbon dioxide) – oxygen is needed for aerobic cellular respiration by all organisms and carbon dioxide is needed for photosynthesis

9 Nutrient groups Your body needs food, because food contains a number of nutrients needed by the body. These are: 1.Carbohydrates 2.Proteins 3.Lipids 4.Vitamins 5.Minerals 6.Water

10 Carbohydrates (Polysaccharides) These substances are used by the body mainly for energy Non digestible carbohydrate (eg cellulose) is called roughage or fibre. It is important to the body because it helps movement of food through the intestines, and prevents bowel cancer and other problems Carbohydrates contain the elements Carbon, Hydrogen and Oxygen Foods containing carbohydrates include: cereals eg rice, wheat, oats; bread, pasta, cakes, biscuits, potatoes and other starchy vegetables

11 Carbohydrates Carbohydrates are huge molecules. They are made up of many small subunits called saccharides The simplest kind of sugar is a monosaccharide eg glucose and fructose Polysaccharides are long chains of monosaccharides joined together eg starch, glycogen

12 Proteins (polypeptides) These substances are used by the body for body structures eg hair, muscle, skin; enzymes; blood components eg haemoglobin, clotting factors Proteins contain the elements Carbon, Hydrogen, Oxygen and Nitrogen, and sometimes Sulfur and/or Phosphorus. Foods containing proteins include: meat, fish, poultry, eggs, soy, nuts, legumes – eg peas, beans

13 Proteins The basic unit of a protein is an Amino acid Amino acids join together in long chains to form polypeptides These chains can be very long. The hormone Insulin is 55,000 amino acids long. Sometimes two or more long chains stick together to form one working protein. Haemoglobin is formed from 4 polypeptide chains working together

14 Types of amino acids Amino acids differ by having different R groups - for example the amino acid glycine has an R group made of just “H” There are 20 different types of amino acids, of which 9 are essential amino acids An essential amino acid is one that the body can’t make. It must get this essential amino acid by eating food that contains the essential amino acid

15 LIPIDS (fats) These substances are used by the body for energy reserves, insulation an protection and to make cell membranes, hormones and for normal skin and brain function Fats contain the elements Carbon, Hydrogen and Oxygen Unlike carbohydrates, lipids always contain much more hydrogen than oxygen. Lipids are made from two kinds of molecular units joined together in the shape of the letter “E”: Foods containing lipids include: butter, margarine, oils, milk, cheese, cream, nuts, fish Glycerol and Fatty acids

16 Lipids Lipids can be saturated or unsaturated. Saturated means there are no double bonds between the carbon atoms. This means that they are difficult for the body to break down and use. Instead they get stored in the adipose cells (fat cells) Unsaturated fatty acids have double bonds between carbon atoms. The double bonds make the whole structure unstable so this molecule is easy for the body to break down and release the stored energy

17 Vitamins There are a number of vitamins needed by the body. Most act as co-factors for enzymes in metabolic reactions. The fat-soluble vitamins are A, D, E and K and the water- soluble vitamins are B and C. Sources of vitamins include fruit and vegetables Water-soluble vitamins are easily lost in cooking and preserving, so the best sources are fresh or raw fruit and vegetables Excesses of vitamins can also cause problems, including vitamin A toxicity.

18 Vitamin functions VitaminFunction AHelps with immunity, night vision and skin health, normal growth of foetal cells B group (including folate, niacin and thiamine) Helps with metabolism, red blood cell manufacture (making haemoglobin) Helps prevent spina bifida if taken by pregnant woman CPrevents scurvy – helps with immune system DHelps with bones and teeth – prevents osteoporosis and rickets EHelps with immunity and skin health KHelp with clotting

19 Minerals There are many minerals used by the body. Most act as cofactors for enzymes in metabolic reactions. Excesses of some minerals can also cause problems, eg copper is poisonous if taken in large amounts. Sources of minerals include milk and dairy products, bony fish (eg sardines, tuna), liver, kidney, meat, baked beans, chicken, egg yolk, wheat germ

20 Mineral functions MineralFunction CalciumHealthy bones and teeth – prevents osteoporosis and rickets IronHaemoglobin manufacture – prevents anaemia IodineHelps metabolism – prevents goitre CopperAnaemia FluorineHelps healthy teeth ZincHelps with healthy tooth enamel

21 Water Water is used for for dissolving chemicals, regulation of body temperature and waste removal Sources of water include water and other drinks, fruits and vegetables

22 Organisms produce wastes The wastes produced depend on diet: Carbohydrates are broken down into carbon dioxide and water Fats are broken down into carbon dioxide and water Proteins are broken down into carbohydrates and ammonia The greater the amount of protein in the diet, the more ammonia produced

23 Cells need to remove wastes Wastes can have serious effects on cells: Carbon dioxide toxic waste, decreases pH Ammonia toxic waste, increases pH Excess salts alters osmotic pressure – drags in water Excess water alters osmotic pressure – can burst cells

24 Nitrogenous wastes These come from the breakdown of In deamination the amine group is removed The carbohydrate is then used for energy or stored The amine group turns into ammonia which can be excreted or turned into urea or uric acid for excretion Carbohydrate Amine group

25 Wastes depend on lifestyle Herbivores eat plant material and produce small amounts of nitrogenous wastes Carnivores eat meat and produce large amounts of nitrogenous wastes


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