L4- Nutrition Flashcards
metabolism
chemical processes that occur within organism to maintain life
examples of metabolism
- oxidative pathways
- detoxification pathways
- biosynthetic pathways
- fule storgae and mobilisation pathways
catabolic processes
break down molecules to release energy int he form of reducing powers
e.g. glycogen to glucose
anabolic processes
uses energy and raw materials to make larger molecules for growth and maintenance
e.g. creating glycogen from glucose
why do living thing require energy
1) biosynthetic work- (synthesis of cellular components)
2) transport work (ions and nutrients)
3) mechanical (muscle)
4) electrical (nervous)
energy exists in
interconvertible forms
e.g. nuclear, magnetic, chemical bond, light, heat etc
what sort of energy to cells use
chemical bond energy in the form of ATP
ATP is
broken down to release energy
- breaking phosphodiester bond in ATP releases energy in cells
when ATP is broken down what is formed
ATP –> ADP (adenosine diphosphate) and Pi (inorganic Phosphate)
what simple process causes ATP to be reproduced
ADP and Pi are converted back to ATP during oxidation of:
- lipids
- CHOs
- proteins
- alchohol
storage of ATP
non existant
- uses glycogen and other stores that can be rapidly oxidised to generate ATP
how much glycogen the live
100g - acts as a b mood glucose bugger
patient will go into comma if
hypoglycemic
official SI unit of food energy
Kilojoule (kJ)
the term ‘calorie’ is
commonly used by physicians because it is understood by patients
1 cal of soft drink has how much kcal of energy
1kcal
1kcal =
4.2 kJ
how much food do we eat s year
500g
carbohydrates
supply energy
proteins supply
energy and amino acids
fat
energy and essential fatty acids
water
maintains hydration
fibre
necessary for normal GI function
minerals and vitamins essential for
normal bodiliy functions
name the main components of our diets
- CHO
- Fat
- Protein
- vitmains
- mineral
- water
- fibre
general formula for CHO
(CH2O)n
- contain aldehyde or ketone group (multiple OH groups)
CHOs can be classified as
- monosaccharides
- disachharides
- oligosaccharides
- polysaccharides
monosaccharides
o Single sugar units (3-9 C-atoms) i. Triose sugars (3 carbons) ii. Pentose sugars (5 carbons) iii. Hexose sugars (6 carbons) o E.g. Glucose
disaccharides
o 2 units
o Lactose – glucose and galactose
o Sucrose- glucose and fructose
o Maltose- glucose and glucose
polysaccharides
o 10-1000 units
o Glycogen
o Starch
o Cellulose- cant break this down because humans lack enzymes (still dietary fibre)
major dietary CHOs
- starch
- sucrose (table sugar)
- lactose (milk sugar)
- fructose (fruit sugar)
- glucose
- maltose
- glycogen
carbohydrate is a
polymer of glucose
sucrose
disaccharide
- glucose and fructose
lactose
disaccharides
- glucose-galactose disaccharide
fructose
monosacchairde
maltose
glucose-glucose
glucogen
CHO storage molecule in animals- polymer of glucose
digestion of CHOs
converts larger carbohydrates to monosaccharides that can be absorbed into the blood
proteins are composed of
amino acids join to form linear chains
digestion breaks proteins down to
amino acids which enter the blood
how many different amino acids used for protein synthesis in the body
20
how many essential amino acids (which cannot be synthesised and must be obtained by the diet)
9
certain amino acids are
conditionally essential e.g. children and poignant women have a higher rate of protein synthesis (require supplementing arg, try and cys in diet)
protein of animal origin
high quality- contain all AAs
protein of plant
lower quality since most are defiance tin one or more essential amino acid
name 9 essential amino acids
(If Learned This Huge List May Prove Truly Valuable)
Isoleucine Lysine Threonine Histidine Leucine Methionine Phenylalanine
Fat are lipids composed of
triacylglycerol (TAG)
triacylglycerol is composed of
3 fatty acids esterified to one glycerol
TAG is stored in
adipose tissue
why are fats the most energy rich store
contain much less oxygen than CHOs or protein, therefor more is reduced so yield more energy when oxidised
which vitamins are required for absorption of fat in the gut
vitamines A, D, E and K
saturated fats
no double bond
unsaturated fats
at least one double bond
trans fats
artificial fats where hydrogens are found on either Sid eof the double bond
fats provide essential
fatty acids e.g. linoleum and linolenic acids which cannot be synthesised by the body
key electrolytes
sodum
potassium
chloride
importance of electrolytes (minerals)
establish ion gradients across membranes and maintain water balance
how much Na+, K+, Cl- per day
1mmol/kg/day each
how much water ra day
30 ml/kg/day
which minerals are essential for structure (bones and teeth)
calcium and phosphorus
calcium is also an important
signalling moelcule
enzyme cofactors
Fe, Mg, Cu, Zn
deficiency of vitamins leads to
disease
vitamins are either
fat or water soluble
name some fat soluble vitamins
A
D
E
K
vitamin D deficiency
Rickets
vitamin E deficiency
neurologic abnormalities
vitamin K deficiency
defective blood clotting
name some water soluble vitamins
B1 B12 B6 Biotin C Choline Folate Niacin
B12 deficiency
anemia
folate deficiency
neural tube defects and anaemia
dietary fibres found in
cereal foods (bread, beans, fruit and veg)
examples of fibres
cellulose
ligin
pectins
cellulose is a
polymer of glucose
why can humans not digest cellulose
we do not have the enzymes required to break the B1-4 linkages in cellulose
- cannot be broken down and absorbed
Fibre is essential for
normal functioning of the GI tract
how much fibre per day
18g/day
average fibre intake for female
12.8g
average fibre intake for men
14.8g
low fibre associated with
constipation and bowel cancer
high fibre diet
reduces cholesterol and risk of diabetes.
