Nutrition
the life activities by which organisms obtain and process (digest) nutrients for energy , growth and repair.
Food is taken
into the mouth |
Food particles being broken down mechanically and chemically
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Small soluble food particles pass through the gut wall into the blood capillaries
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The small food soluble food molecules enter cells and are used for processes such as respiration, cell growth, mitosis
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Undigested food which is not used (eg. fibre) leaves the anus as faeces
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Food consists of four different types of bio-molecules.
Each have an important role in the body!
Each have an important role in the body!
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Carbohydrates
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Lipids
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Proteins
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Monosaccharides
The simplest type of carbohydrate - this does not need to be broken down any further. Monosaccharides are absorbed easily by the body due to their small molecular structure. Glucose and fructose are examples of monosaccharides.
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Disaccharides
When two carbohydrate molecules are joined together. During digestion, these are easily broken down into monosaccharides. Sucrose (table sugar), maltose and lactose are examples of disaccharides.
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Polysaccharides
Many carbohydrate units joined together and either folded, coiled or branched form a polysaccharide. Starch, glycogen and cellulose are all examples of polysaccharides and they take a longer time (and more energy) to break down into monosaccharides so they are small enough to be absorbed into the bloodstream.
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Fats
Fats are from animals. They are full of energy but the energy is not readily available - it must be converted to other substances before the body is able to use it. Besides storing energy, fats are great for insulation (in cold climates!). The use of fat is particularly well developed in whales, which live in cold water and do not have any fur to help them keep warm.
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Oils
Oils are from plants. They, like fats, are great for storing energy but require conversion before the energy becomes available for the body to use.
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Proteins are vital for all animals because they assist in making new cells for growth and repair. Proteins are made of amino acids, and when digested these amino acids enter the bloodstream and are used by cells to form different proteins. Protein cannot be stored by the body (unlike carbs and lipids). Excess amounts of protein can be converted into glycogen (stored energy) or excreted in the urine once the liver has converted it into urea.
The structure and function of the digestive system of each mammal is related to its diet.
Types of diet:
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Herbivore diet
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Carnivore diet
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Filter-feeder diet
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Grass | Bark | Leaves | Branches | Moss | Fruit | Roots
Not-so-good aspects of this diet
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Good aspects of this diet
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Soft tissue | Bone marrow
Not-so-good aspects of this diet
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Good aspects of this diet
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Krill | Copepods
Not-so-good aspects of this diet
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Good aspects of this diet
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This means these mammals must have adaptations for:
Herbivore |
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Carnivore |
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Filter-feeder |
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