energy topic 3 Flashcards
what are the 3 major energy sources?
carbs - major lipids - v. concentrated protein - can be used if insufficient of others
what makes up carbs
CHO
what are carbs the major source in?
plants
what are the 2 classifications of carbs?
sugars and non sugars, dependant on no of C
what is a sugar?
carb with <10 monosaccharides
oligosaccharides (all sugars but monosaccharides)
what is a non-sugar?
either polysaccharide (polymer of a mono) or complex carb (carbs + non carb molecules)
what are the 2 isomeric forms of monosaccharide sugars and which is more biologically sig?
2 isomeric forms e.g. glucose D MOST BIOLOGICALLY IMPORTANT L
what is the 2 nutritional classifications of carbs?
fibrous (insoluble) and non-fibrous (soluble)
which form of carb is more digestable?
non-fibrous (soluble), readily absorbed across SI wall
give an example of a soluble (non-fibrous) carb
monosaccharides-glucose
di- lactose
poly- starch
what is the difference in digestion of soluble (non-fibrous) in ruminants and monogastrics?
monogastric
- solubles digested by own enzymes in SI, simple sugars absorbed into blood stream >energy
ruminants
- via microbe digestion in rumen, VFA absorbed into blood stream> energy
what are fibrous (insoluble) carbs?
structural components of plants, monosaccharides strongly bonded. increase with age of plant
e.g. cellulose and hemicellulose
can animals breakdown soluble carbs?
NO
aniamal enzymes cannot digest
what is the difference in fibrous digestion in mongastrics and ruminants?
monogastrics
- in LI by enzymes, end product of VFA
ruminants
- in rumen by microbial enzymes, end product VFA
how do monogastrics breakdown fibrous carbs?
in LI, have similar microbes to ruminants to breakdown secrete enzymes (e.g. cellulase) capable of breaking bonds
end product =VFA
how do ruminants breakdown fibrous carbs?
in rumen by microbial enzymes, end product VFA
what are hind and foregut fermenters?
hindgut
- monogastric
fore
- ruminant
why do ruminants utilise fibrous insoluble carbs more efficiently then mongastrics?
- microbe pop in rumen bigger then LI
- digesta spends longer in rumen
- ruminants regurgitate
draw the digestion of carbs in a ruminant
page 54
what are 3 VFA and what happens to them?
acetate, butyrate and propinate
the byproduct of metabolism
absorbed across rumen and into bloodstream
transported to liver
used as energy
what are 4 fibrous components of the cell wall?
hemicullose
cellulose
structural protiens
lingnin
what are 4 non-fibrous components of the cell wall?
lipds sugars starch NPN protein
define hemicellulose
fibrous structural component of the plant cell wall
concentration increases with plant age, higher in grasses then legumes.
affects digestibility
alkali soluble cell wall polysaccharide of hexoses and pentoses
what is cellulose?
fibrous structural component of a cell wall
insoluble linear polymer of D glucose molecules
microbial fermentation breaks down, yields glucose
what is lignin?
not a carb
group of compounds which are a polymer of phenolic acid
completely indigestible, increases structural rigidity decreases plant digestibility
Are structural proteins indigestible?
yes, highly indigestible
what is tannin?
non-fibrous, soluble
bitter taste, reduces consumption
stable foam fermentation in rumen by binding and precipitating proteins
= prevention of bloat
what are lipids?
organic compound insoluble to water but soluble in solvents
how can a lipid be classified chemically?
glycerol
- more common
non-glycerol based
what are 2 nutritionally important lipids?
fats
- solid at room temp
oils
- liquid
what is the energy of fat compared to carbs?
1g fat - 39.6 kJ
1g carb- 17.6kJ
what are the 3 types of fat?
monoglyceride
- 1 glycerol and 1 fatty acid
di
- 1 gly, 2 FA
tri
-1 gly, 3 FA
what form are oils generally found?
triglyceride
what is the simplest FA
VFA- acetic acid
what are the 2 types of lipids found in plants?
structural
- in membranes and protective layers
storage
- in fruits and seeds, mainly as oil
what is the role of lipids in animals?
energy storage
- mainly as fat
electron and substrate carriers
vitamin absorption
in membranes
structural
- small part in muscle and adipose tissue
what are the 2 forms of glycerol lipids
simple
- esters of FA with alcohols
- e.g. fats, oils waxes
compound
- esters of FA with alcohols and non-lipid substances (e.g. K, carbs)
- e.g. phospholipids, glycolipids
what is a non-glycerol lipid?
one of two types of lipids (glycerol lipid)
includes sterols and terpenes
where does fat digestion occur in monogastric and ruminant?
monogastric
- SI
ruminant
- poor ability to digest in rumen
- digested in SI
how does the mongastric digest fat?
bile salts secreted into SI
- emulsify fats
SA increased by
- churning of intestines
- emulsification by bile salts (breaks down fats)
pancreatic lipase enzyme breaks down monoglycerides and free FA
- mix with bile salts to form mixed micelles which are absorbed by passive diffusion
once absorbed across SI wall, resyn back to triglycerides then enter blood stream via lyph fluid
how does the ruminant digest fat?
microbes of rumen ability to digest fat limited
- adversely affects microbes
- limit to 7% of diet
too much fat= reduced production
long chain FA not absorbed well
- saturated by bacterial lipases before they reach the SI
- then absorbed and stored as highly saturated
lipids then absorbed in SI similar to mongastric
what is the difference in storage of mongastrics and ruminants in lipids?
mongastrics
- saturated or unsaturated
- matches what animal fed
ruminant
- highly saturated regardless by what is fed
what are essential FA?
fatty acids the body cannot synthesise needed for lipoproteins - cell membranes prostaglandins - hormones
what are symptoms of a deficiency in EFA?
abnormal skin and poor growth,
fresh pasture excellent source of EFA
what are FA used for>
transported to liver for;
- storage of fats
- energy source
- syn other compounds (e.g. steroids)
why is fat needed in the diet?
EFA and absorption of fat soluble vitamins
what is a FA?
chains of C with a carboxyl group at the end of each chain and a R group
what is the difference between saturated and unsaturated FA?
saturated
- have no double bonds
unsaturated
- 1+ double bond
what is the major difference between monogastrics and ruminantsin their digestion of fat
monogastrics
- absorbed in SI with the aid of pancreatic enzymes and bile salts
- storage of fats matches whats ingested
ruminants
- doesn’t digest FA well, affects microbes
- fully saturated in rumen by bacterial lipases and absorbed highly saturated regardless of how ingested
what are 2 EFA?
Linoleic and linolenic acid
what are micelles?
aggregation of molecules in a colloidal solution
micelles in digestion
- pancreatic lipases breaking down fat
mixed micelles
- FFA, mono with bile salts
