Nutrition Flashcards
What is autotrophic nutrition?
Simple inorganic molecules built up into complex organic molecules
What is photoautrophic nutrition?
Organisms that use light energy to convert simple inorganic molecules into complex organic ones.
.Chlorophyll is used to absorb sunlight energy
What is an example of an organism that uses photoautrophic nutrition?
Green plants, such as Dandelion, Algae and certain bacteria
What is chemoautrophic nutrition?
.Use the energy derived from special methods of respiration (such as the oxidation of hydrogen sulphide/ sulphur/ ferrous ions or nitrates) to convert simple inorganic molecules into complex organic ones.
What is an example of an organism that uses chemoautotrophic nutrition?
Bacteria eg nitrosomonas
Define heterotrophic nutrition?
Complex organic molecules broken down to release energy (consumers)
How does digestion work in holozoic feeders ?
Food is processed as it passes along the gut
How does the structure of the gut differ between simple organisms that eat one type of food and more complex organisms?
Simple organisms have a undifferentiated gut, where as advanced organisms with a varied diet have a divided gut
Why are complex organisms gut divided?
Allows for specialisation for specific functions like, ingestion, digestion, adsorption and egestion.
What do saprotrophs/ saprobionts feed on?
Dead or decaying matter
What organisms are classed as saprotrophs/ saprobionts?
All fungi and some bacteria
What type of digestion do saprotrophs/ saprobionts carry out?
Extracellular
What is extracellular digestion?
When enzymes are secreted onto food outside the body then soluble products of digestion are adsorbed by diffusion across the cell membrane.
Describe the process of fungal feeding?
- Fungi secrete enzymes from the growing tip of the hyphae which penetrates the food to secrete the enzymes.
- The enzymes diffuses out through the cell membrane and cell wall onto the surface of the food (Substrate)
- These enzymes digest the food into soluble products
- These soluble products are the absorbed into the hyphae through the cell wall and cell membrane by facilitated diffusion or active transport.
- The soluble products are transported within the fungi and excess are stored
- This is extracellular digestion
What is a parasite?
An organism that feeds on or in another organisms (host)
Where do parasites live?
On or in the host
What happens to the host of a parasite?
Harm or death
What is the case study example for parasites?
Tapeworms
What is mutalism?
Also known as symbiosis and involves a close association between members of two different species.
(When two different species rely on each other for survival)
Why do different parts of the human gut have different pH values?
Different enzymes have different optimum pH
What type of feeder is amoeba?
Amoeba which are protocista are holozoic feeders
Describe the structure of amoeba?
They are a single celled organisms with a large surface area to volume ratio
How do amoeba obtain their nutrition?
They obtain their nutrients by diffusion, facilitated diffusion or active transport across their cell surface membrane
How do amoeba take in larger molecules?
By endocytosis, which in turn fuse with lysosomes so that the contents can be digested
What happens to the products of digestion in amoeba?
The products of digestion are absorbed into the cytoplasm and ingestible material is egested by exocytosis.
What is ingestion?
Large food particles are taken into the buccal cavity
What is Mechanical Digestion?
The action of teeth, saliva and the tongue (mastication) so it may then move into the gut
What is chemical digestion?
The chemical breakdown (enzymes) of large insoluble molecules to small, soluble molecules. (Different regions of the gut have different pH therefore the enzymes found in the different regions have different pH optima)
What is absorption?
Small, soluble food molecules move from the small intestine into the blood stream.
What is the serosa and what is its function?
Tough connective tissue covered by squamous epithelium that protects the wall of the gut and reduces friction from other organs in the abdomen as the gut moves during the digestive process.
What is the Muscle layer and what is its function?
Circular and longitudinal muscle, cause waves of muscular contractions, peristalsis which propels food along the gut. Behind the food the circular muscles contract and the longitudinal muscle relaxes.
What is the sub-mucosa and what is its function?
Connective tissue containing blood and lymph vessels to take away absorbed food products as well as nerves that co-ordinate the muscular contractions of peristalsis.
What is the Mucosa and what is its function?
The innermost layer (epithelium) that lines the walls of the gut. It secretes mucus from goblet cells which lubricates and protects the mucosa. In some regions it secretes digestive juices in others it absorbs digested food.
What are the 3 main forms of mechanical digestion?
.Crushing action of teeth
.Action of stomach
.Peristaltic action of muscular layers in gut wall
What is the purpose of mechanical digestion?
Mechanical digestion increases surface are of food over which enzymes may act to chemically digest the food.