Adaptations for Nutrition

Looks at the whole topic of 'Adaptions for Nutrition' in WJEC Biology AS. There are a few typos, but nothing that should stop understanding

HideShow resource information
  • Created by: ava.scott
  • Created on: 05-04-14 13:03
View mindmap
  • Adaptations for Nutrition
    • Methods for nutrition
      • Autotropic
        • e.g. plants
      • Heterotophic
        • Consumes complex organic molecules from other organisms
          • Holozoic
            • Takes organic material from other organism and breaks it down inside their body by digestion.
              • e.g. animalia
          • Saphyrophtic
            • These feed on dead or decaying matter. They secrete digestive enzymes such as lipases, proteases and amylase onto the food, digest  it outside the body, and the organic molecules diffuse into the organism.
              • e.g. fungi
          • Parasitic
            • These feed on a host whilst they are alive, usually causing harm whilst doing so.
              • e.g. tape worm
      • Movement in the digestive system
        • Unspecialised guts e.g. worms
        • Digestive system functions
          • Ingestion- bringing food into the body through the mouth
            • Digestion- breaking down food material into its constituent organic molecules e.g. glucose, amino acids and fatty acids.
              • Absorption: The movement of digested molecules into the blood of the organism.
                • Egestion: The removal of indigestible material such as cellulose.
          • MOVES THROUGH THE SYSTEM BY PERISTALSIS.
        • Specialised guts e.g.  humans and ruminants
          • The gut has specialised regions that carry out different functions e.g. the stomach mixes food up, the small intestine absorbs it.
    • The Human Digestive System
      • GUT STRUCTURE
        • The outer serosa consists of tough connective material that protects the gut from friction with other organs in teh body.
        • The muscle layer consists of both outer longitudinal muscle and inner circular muscle.
          • These muscles contract rythmically in a process called peristalsis, which moves the bolus of food along the gut.
        • The sub-mucosa contains blood and lympth vessels that carry digested molecules away from the dogestive sytem and too the cells. It also contains the nerves that coordinate the contractions of peristalsis/
        • The mucosa is the inner-most layer. It secretes mucus to lubricate the digestive trcat so food can mocve smoothly. In some regions it also secretes digestive enzymes, and it others it absorbs food to the vessels benihd the mucosa.
      • Digestion
        • Carbohydrates are broken down into disaccharides and then monosaccahrides, first by amylase and then maltase.
        • Protein is broken down by proteases/peptidases. They are broken into amino acids.
          • Endopeptidases hydrolyse peptide bonds in the middle of the chain. Exopeptidases hydrolyse boinds at the end.
        • Fats are broken down by fatty acids and glycerol by the enzyme lipase.
      • REGIONAL SPECIALISATIONS OF THE GUT
        • Mouth- chews food into manageable size, and lubricates it to become a bolus. Also salivary amylase begins the break down of carbohydrates.
          • The stomach- This sac contracts rythmically to mix food up. The lining epithelial cells secrete gastric juices that contain Hydrochloric acid, which kills off bacteria. Mucus is also secreted to protect the lining of the stomach from digestive enzymes and acid. The main enzymes at work here are peptidases, that are adapted to work in optimum conditions of pH2.0.
            • The small intestine
              • Duodenum: recieves bile from the gallbladder to help emulsify fats, increasing the surface area for lipase to work on. Bile also helps neutralises acidity. The duodenum recieves pancreatic juices that contains all types of enzymes. The duodenum secretes alkali juices and mucus also, from projections called villi.
                • the large intestine- water, mineral salts and vitamins are reabsorbed here.
              • the ileum is adapted for absorption. it is very long, with massive surface area. it is lined with villi, whivh in turn are lined with epithelial cells with microvilli. The villi only have one cell thickness and a very good supply of blood (glucose ajnd amino acids) and lymph vessels (fatty acids and glycerol.) digested products diffuse into vessels, thought some active transport is used to speed up the process.
                • the large intestine- water, mineral salts and vitamins are reabsorbed here.
                • The ileum has a higher concentration of food molecules than the blood/lymph vessels, so they diffuse across DOWN the concentration gradient.
    • ADAPTION FOR DIFFERENT DIETS.
      • DENTITION.
        • Herbivores
          • Incisors on lower jaw only which cut against a horny pad.
            • Canine teeth are indistinguishable.
              • Diastema is a gap between front and back teeth. The tounge works by moving freshly cut grass from the front of the mouth the back.
                • Jaw works in a circular grinding action.
                  • The cheek teeth interlock when put together, and are ground down, increasing grinding efficiency. The teeth have open, unrestricted roots so the teeth keep growing throughout the animals life.
        • Carnivores
          • Sharp incisors for tearing and cutting flesh.
            • Canine teeth are large, curved and pointed.
              • No diastema
                • Jaw works in vertical up-and-down motion, allowing it too open wider to catch prey.
                  • specialised molar teeth called carnaissals, which act like garden shears to slice up meat, sliding past eachother. very jagged and sharp.
      • RUMINANT STOMACH
        • e.g. cows and sheep
          • mutualistic/symbiotic relationship: ruminants eat vegetation but do not have cellulase, the enzyme which breaks down cellulose. To solve this problem, a mustaulistic rekationship has developed between cellulase-producing bacteria and ruminants. The bacteria get shelter and food.
            • the region for the bacteria to live in must be separate to the rest of the stomach,as the bacteria could not survive in such acidic conditions.
              • and also so the bacteria are not digested, and are kept to digest the cellulose.
          • 4 chambered stomach
            • Mouth forms the cud- by chewing plants with saliva.
              • the first chamber- food is mixed with bacteria and fermented for produce glucose. Waste products = CO2 and Methane.
                • 2nd chamber, forms cud again, and regurgitated for further chewing.
                  • swallowed directly into third chamber where water is reabsorbed.
                    • fourth chamber- protein is digested and then moved to the small intestine for absorption.
      • PARASITES
        • These are organisms that live off living organism, usually causing a degree of harm.
        • THE PORK TAPEWORM
          • Problems it faces:
            • Lives surrounded by digestive juices and mucus
              • Peristalsis makes habitation difficult
                • The hosts immune system
                  • extreme pH and conditions of the digestive system.
          • Adaptation:
            • Hookers and suckers for attachment to the wall of the gut.
              • Thick cuticle with inhibitory substances secreted to fend off the hosts immune system and protection for digestive systems.
                • Very basic organs- mainly for reproduction. It doesn't have sensory system.
                  • hermaphrodite- not enough room in the gut for two tape worms, so each segment of the worm contains male and female organs for reproduction. This means each segment can produce up to 40,000 eggs.
                    • The eggs have a strong, resistant covering to survive the outside world until enters the system of another host.
          • Problems it causes:
            • The adult tapeworm causes little discomfort, except a lack of nutrition.
            • Eggs and dormant embryos can form dangerous cysts in various organs.
            • Drugs are very efficient at ridding tape worms
            • Public health measures such as inspection meat are very important.
  • Autotrophic organisms make there own complex organic  molecules by chemical processes such as photosynthesis, using just single molecules CO2 and H2O. They are the producers for all energy in the food chain.
    • e.g. plants
  • The digestive system is consistent throughout its length, carrying out the same function.
    • Unspecialised guts e.g. worms
  • Thick cuticle with inhibitory substances secreted to fend off the hosts immune system and protection for digestive systems.
    • Very basic organs- mainly for reproduction. It doesn't have sensory system.
      • hermaphrodite- not enough room in the gut for two tape worms, so each segment of the worm contains male and female organs for reproduction. This means each segment can produce up to 40,000 eggs.
        • The eggs have a strong, resistant covering to survive the outside world until enters the system of another host.
  • ALL complex organic molecules are broken down by hydrolysis.

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Human, animal and plant physiology resources »