chapter 1 Flashcards
What are the stages of digestion?
Ingestion (oesophagus)
Digestion (stomach - chyme.PH),
Adsorption (small intestine - microvill)
Elimination (large intestine - goblet cells)
What are the parts and functions of a ruminants digestive system?
Rumen - fermentation vat
Reticulum - compacting cud.
Omasum - filter and absorbs
Abomasum - true digestive stomach
How do most vertebrates store energy in the body?
As glycogen in the liver, this is short term energy.
Next a longer term energy is used , fat stores.
Protein is the last option for energy stored in the body.
What are the main digestive enzymes and what do they hydrolise?
Carbohydrases > carbohydrates
Proteases > proteins
Lipases > fats
Nucleases > nucleic acids
A marine teleost is……..
Hypotonic to their surroundings - blood higher water concentration than sea water.
A freshwater fish is…….
Hypertonic to their surroundings - blood has a lower water concentration than freshwater.
How do insects/arachnids osmoregulate?
Various evaporative water loss counter measures:
- small surface area: volume ratio
- waterproofing - waxy cuticle/impermeable integument
- discontinuous ventilation - intermittent opening of spiracles
What is ammonia and ammonium ions?
Most marine mammals excrete this as urine.
- highly toxic
- energetically cheap to produce
- excreted with lots of water.
What is Urea?
Most mammal/amphibians and some fishes/reptiles/ terrestrial invertebrates excrete this as urine.
- moderately toxic
- energetically costly production (3 x ATP = 1 x urea)
- excreted with some water.
What is Uric acid?
Birds, insects and most reptiles excrete this as urine.
- low toxicity
- energetically costly to produce (4x ATP = 1x Uric acid)
- excreted with almost no water.
What do insects/arachnids/tardigrades use to secrete Uric acid?
Malphigian tubes
What is a nephron?
The functional unit of the kidney and is responsible for glomerular filtration and tubular reabsorption/secretion.
How do substances enter/exitt cells?
i) simple diffusion
ii) passive transport - channel mediated (small - polar)
NO ENERGY - carrier mediated (larger - polar)
iii) diffusion
iv) active transport - using specific carrier proteins
against an electrochemical gradient.
How are larger molecules transported in/out of cell?
endocytosis (import into cell)
- phagocytosis - import in solid “cell eating”
- pinocytosis - import in liquid “cell drinking”
Exocytosis (export out of cell)
What is a cell membrane?
Phospholipid bilayer
- hydrophillic heads (water loving) - polar
- hydrophobic tails (water hating) - non polar
