1 3 6 7 Structural Metabolic Roles of

1. 3. 6 + 7 Structural & Metabolic Roles of Biomolecules

Need to know • Structural Role of Biomolecules • State carbohydrates role as cellulose in cell walls • State proteins role as fibrous protein e. g. keratin or as myosin • State the role of lipids as Phospholipids in cell membranes 2

What does the ‘Structural Role of Biomolecules’ mean? Structure = the way in which something is built e. g. timber structure, steel structure Role = function/job or position Biomolecules = carbohydrates, fats, proteins Structural Role of Biomolecules = the function/job of carbohydrates, fats, proteins in making various parts of living things 3

Structural role of Carbohydrate Cell Structure • Cellulose found in plant cell walls • Cotton fibres represent the purest natural form of cellulose, containing more than 90% of this fibre • Chitin found in fungal cell walls and insect exoskeletons 4

Structural role of Proteins Cell structure • Proteins are fibrous (threadlike) in nature. • They combine with phospholipids to from cell membranes (lipoproteins) • Keratin is the structural protein in skin, hair and nails • Myosin is the structural protein in muscle 5

Learning check What does the ‘Structural Role of Biomolecules’ mean? Structural Role of Biomolecules = the function / job of carbohydrates, fats, proteins in making various parts of living things 6

Structural role of Lipids Cell Structure • Important storage molecules in organisms • Heat insulation – e. g. under the skin • Waterproof the body • Protection around body organs e. g. kidney, heart • Phospholipids and lipoproteins are major components in cell membranes 7 • Myelin helps transmit messages in nerve cells

Learning check What is the structural role of proteins? • Proteins are fibrous (threadlike) in nature. • They combine with phospholipids to from cell membranes (lipoproteins) • Keratin is the structural protein in skin, hair and nails • Myosin is the structural protein in muscle 8

1. 3. 7 Metabolic Role of Biomolecules

Need to know • State that carbohydrates & lipids act as a primary source of energy • State that proteins act as enzymes and are made of amino acids • State that hormones (protein) act as regulators of metabolic activity • State that vitamin C & D are used for tissue growth, cell production and health maintenance • Name disorders associated with deficiency of a water soluble and a fat-soluble vitamin 10

What does the ‘Metabolic Role of Biomolecules’ mean? Metabolic = metabolism = all the chemical reactions in a cell Role = function/job or position/involvement Biomolecules = carbohydrates, fats, proteins Metabolic Role of Biomolecules = the function / job / involvement of carbohydrates, fats, proteins in the chemical reactions in cells making various substances 11 for living things

Metabolic Role of Carbohydrates and Lipids These are the primary sources of energy for metabolism – e. g. • glucose (carbohydrate) is an immediate source of energy • lipids are a long-term energy storage 12

Metabolic Role of Carbohydrates and Lipids They are important in the following processes: Respiration – energy is released when glucose is broken down to form carbon dioxide and water – catabolism Photosynthesis – glucose molecules are made from carbon dioxide and water using the sun’s energy – anabolism 13

Metabolic Role of Proteins All enzymes are proteins and have a folded shape. Enzymes control the chemical reactions in cells. e. g. enzymes control the processes of photosynthesis and respiration Chlorophyll is a protein that traps the sun’s energy during photosynthesis 14

Learning check 1. Give examples of the primary sources of energy for metabolism Glucose & Lipids 2. Name two important metabolic pathways and state whether they are anabolic or catabolic Photosynthesis – anabolic Respiration – catabolic 15

Metabolic Role of Hormones regulate body functions e. g. the hormone insulin controls the amount of glucose in the blood Oestrogen, progesterone and testosterone are other hormones controlling human sexual development 16

Learning check What is the metabolic role of protein? Enzymes are proteins. Enzymes control the processes of photosynthesis and respiration Chlorophyll is a protein that traps the sun’s energy during photosynthesis 17

Metabolic Role of Vitamins Definition: can you remember it Vitamins are essential organic catalysts of metabolism They are needed in small amounts for the correct functioning of the body They cannot be made by the body They must be in the diet 18

Vitamin C Chemical name: ascorbic acid Solubility: water soluble Function: for building connective tissue i. e. tissue used for attaching organs together or for protection, e. g. skin, blood vessels, bone, tendons, cartilage, ligaments Source: Citrus Fruits, Green vegetables 19

Vitamin D Chemical name: calciferol Solubility: fat soluble Function: needed to absorb calcium from food. Calcium needed for healthy teeth and bone formation and their maintenance Source: Dairy products, fish liver oils, egg yolk, made by skin in sunlight 20

Learning check For the vitamins C & D give the following The chemical name Solubility Function Source in the diet Vit C Vit D - Ascorbic acid Calciferol - Water soluble Fat soluble - Connective Absorb tissue calcium formation - One source 21 One source

Vitamin deficiency disorders Lack of Vitamin C causes scurvy Symptoms: soft bleeding gums, bad and loose teeth Lack of Vitamin D causes rickets in young children Symptoms: softening of the bones of the spinal column and bowlegs osteomalacia in adults Symptoms: the bones lose calcium and become 22 weak – common in vegans

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