Adaptations for nutrition 2.4 Flashcards
What is an autotroph?
Organisms that use simple inorganic materials to manufacture complex organic compounds. i.e. plants and bacteria
What is a chemotroph?
Use energy from chemical reactions (less efficient than photosynthesis) e.g bacteria
What is a phototroph?
Use light to carry out photosynthesis. e.g photoplankton, plants
What is a heterotroph?
Organisms that consume complex organic food material made by autotrophs. i.e. animals, fungi, some bacteria
What are saprophytes?
Fungi and some bacteria. extracellular digestion
What are holozoic heterotrophs?
Humans. Internal digestive system
What are parasites?
Body louse (ectoparasite)
Tapeworm (endoparasite)
How does saprophytic digestion work?
-Secrete enzymes onto food outside the body
- Absorb the soluble products across the cell membrane by diffusion
-Extracellular digestion
How does parasitic digestion work?
-An organism that obtains nutrients from another living organism or host
-This causes harm to the host
-Highly specialised for its way of life
How does holozoic digestion work?
-Ingest food and digested internally
-Indigestible parts egested
What is ingestion?
Taking in food
What is digestion?
Breakdown of large insoluble molecules into small soluble molecules to absorb into blood
What is absorption?
Molecules and ions pass through gut walls
What is assimilation?
Products of digestion are used by cells
What is egestion?
Elimination of undigested food
What is the serosa?
layer of connective tissues, reduces friction with other organs
What is the circular and longitudinal muscle?
Contracts behind the bolus of food, produces peristaltic waves
What is the submucosa?
Blood and lymph nodes remove products and nerves coordinate peristalsis
What is the mucosa?
Secretes mucus (some regions secrete digestive enzymes)
What is digested in the duodenum?
Protein-> peptides
peptides-> amino acids
starch-> maltose
lipids-> fatty acids and glycerol
What is digested in the ileum?
polypeptides, dipeptides, disaccharides
What adaptations does the small intestine have for absorption?
-very long with folded surface
-folds have villi and microvilli
-epithelium is one cell thick
-rich blood supply
-many mitochondria for ATP for active transport
Where do the blood vessels in the villi lead to?
the liver
What are the epithelial cells and their functions?
goblet cells-secret mucus
Absorptive cells- contain numerous mitochondria and a brush border of microvilli
How do triglycerides diffuse across the epithelum?
-Fatty acids and glycerol diffuse as micelles
-Chylomicrons made by golgi body leave via exocytosis and diffuse into lacteal
-Pass through lymphatic system to bloodstream opening at thoracic duct
What is glucose used for?
-Energy release in respiration
-Excess glucose stored as fat
What are amino acids used for?
-Absorbed for protein synthesis
-Excess deaminated, converted to urea (remainder stored or used in respiration)
What are lipids used for?
-Membranes + hormones
-Excess stored as fat
