BY2 - Nutrition
- Created by: beth-marie2511
- Created on: 19-03-16 17:02
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- BY2 - Nutrition
- Methods of Nuritiion
- Organisms need to obtain nutrients to provide energy to maintain life function.
- Autotrophic Nutrition (Autotrophs)
- Use inorganic molecules to synthesise organic compounds.
- CCO2 + H20 --> Glucose
- e.g. Plants/Algae
- Heterotrophic Nutrition (Heterotrophs)
- Organisms cannot make their own food.
- Have to consume complex organic molecules, produced by autotrophs.
- This is either done by autotrophs or other heterotrophs.
- e.g. Animals/Fungi
- Holozoic Feeders
- Carnivores
- Feed on other animals.
- Herbivores
- Feed solely on plant material.
- Detritivores
- Animals that feed on dead and decaying material.
- Includes nearly all animals - food is broken down internally via digestion.
- Carnivores
- Saprophytes (Saprobionts)
- Secretes enzymes onto food outside the body and absorb the products by diffusion (extracellular diffusion)
- e.g. Bacteria
- Parasites
- Live in/on a host and obtain nourishment at the expense of the host.
- e.g. Tapeworm
- Digestion
- The breakdown of large, insoluble molecules into smaller, soluble molecules by enzymes.
- 4 Main Processes
- 1. Ingestion
- Taking food into the body via the mouth (or buccal cavity)
- 2. Digestion
- Chemical (enzymes) or mechanical (teeth or stomach) digestion.
- 3. Absorption
- Digested small, soluble molecules pass through the gut wall and into the blood.
- 4. Egestion
- Elimination of undigested food from the body.
- e.g faeces or cellulose or bacteria or dead cells.
- Elimination of undigested food from the body.
- 1. Ingestion
- Structure of the Human Gut.
- Outer Layer = Outer Serosa
- Function: To protect the gut and reduce friction from other organs.
- Strong
- Made up of connective tissue.
- 2nd Layer = Muscle
- Inner circular muscles.
- Outer longitudinal muscles.
- Function: Peristalsis and to push food along the gut.
- 3rd Layer = Sub-mucosa
- Connective tissues containing vessels, nerve and lymph.
- Function (Blood vessels and Lymph) - to take away or transport absorbed food products.
- Function (Nerves) - coordinating peristalsis.
- 4th Layer = Mucosa
- Internal layer that lines the gut.
- Secretes enzymes in some areas.
- Secretes mucus to lubricate food and to protect the mucosa.
- Outer Layer = Outer Serosa
- Parasites
- Organisms that live in or on a host and obtain nutrients at the expense of the host.
- Features of Pork Tapeworm (Taenia Solium)
- Suckers or Hooks
- Form an attachment to the gut of the host.
- Large surface area to volume ratio.
- Maximises absorption of nutrients because there is no digestive sytem.
- Body Covering (Thick Cuticle)
- Resistant to the host's digestive enzymes.
- Protection from immune system of the host.
- Hermaphrodite
- Suckers or Hooks
- Methods of Nuritiion
- Reproduces a large number of eggs.
- Increases chance of survival.
- Hermaphrodite
- Increases chance of infecting a new host.
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