Nutrients and Macromolecules Flashcards
Define nutrients
chemicals taken into body to produce ATP, maintains homeostasis, provide building blocks to create other molecules (amino acids)
> carbohydrates, proteins, lipids, vitamins, minerals, water
Macromolecules
carbs, proteins, and lipids - major organic nutrients, required in large amounts by the body
Vitamins and minerals
Smaller molecules, requires less of them, enter body without being digested
Carbohydrates
Most come from plants
Contain carbon, hydrogen and oxygen
2H and 1O for every C
Large molecules made up of small building blocks (monosaccharides)
Monosaccharides
- glucose - blood sugar
- fructose - fruit
- galactose - milk
Disaccharides
- sucrose - glucose and fructose
- lactose - glucose and galactose
- maltose - glucose and glucose
Polysaccharides
Long chains of 3000+ monosaccharides
- glycogen, starch and cellulose
Glycogen - polysaccharides
> animal polysaccharides
> glucose molecules
> stored in humans in liver and muscle
Starch and cellulose - polysaccharides
> plant polysaccharides
> starch broken down into energy
> cellulose - dietary fibre; can’t be broken down
Digestion of polysaccharides
saliva (oral cavity), pancreatic amylase (duodenum)
Digestion of disaccharides
digested by enzymes in the intestine
Digestion of monosaccharides
glucose absrobed into blood via villi; transported to liver via hepatic portal vein
Carbohydrates - uses in the body
- glucose - ATP
- excess glucose - glycogen and stored in muscle and liver cells
- excess beyond storage - fat
Sugars also make up DNA, RNA, ATP, glycoproteins, glycolipids (plasma membrane)
Proteins
Contains carbon, hydrogen, oxygen and nitrogen (sometimes sulphur)
Made of amino acids - amine group (NH2), carboxyl group (COOH) and side group (differs between AA)
AA link together to form peptides and proteins
Essential amino acids
can’t be produced by the body; must be absorbed through diet (9 in total - eg. histodine)
Non-essential amino acids
Can be synthesised from essential aa’s - still required by the body
Peptide bonds
covalant bonds formed between aa’s during protein synthesis
Digestion of protein
pepsin in stomach
Digestion of polypeptides
trypsin in duodenum, villi/microvilli
Digestion of amino acids
Into blood via villi/microvilli
Proteins - uses in the body
Regulates body functions:
- globular proteins
- structural - muscle proteins
- cell membrane transport
- enzymes
- hormones
- antibodies
Complete proteins
Contains enough of all essential aa’s
- fish, poultry, milk
Incomplete proteins
Must mix to get all aa’s
- green veges, grains, legumes
Lipids
C, H, O - sometimes nitrogen and phosphorus
> lower O:C compared to carbs - insoluable in water
Lipids/fats broken down into energy
Triglycerides
Glycerol and 3 fatty acids - makes up 95% of fats in the body
Different lengths (14/18 C atoms)
Saturation depends on number of H atoms on each chain
Saturated fats
come from animal fats
Unsaturated fats
Plant fats
Monounsaturated fats
olive and peanut oil
Polyunsaturated fats
sunflower and fish oil
Transfat
unsaturated fats artificially altered to be more saturated (increases shelf life)
Lipid digestion
Begins in duodenum - bile from gall bladder emulsifies fats
Lipase from pancreas - further breakdowns
Monoglycerides absorbed into lymphatic system via lacteals
Stored in adipose tissue and liver until needed
Lipids: function in the body
- Triglycerides - produce ATP (excess stored in adipose, liver)
- Cholesterol - component of plasma membranes, modified to form bile salts
- Phospholipids - major components of plasma membranes, myelin sheath, part of bile
- Eicosanoids - derived from fatty acids; involved in inflammation, blood clotting, tissue repair, smooth muscle contraction
Water absorption
~9L enters digestive tract each day
99% of water entering intestine is absorbed
Can move across the intestinal wall in either direction
Ions (sodium, potassium, calcium, magnesium, phosphate) activity transported
Vitamins
Organic molecules in small quantities in food
Essential for normal metabolism; can’t be produced in body (vitamin C)
Some vitamins produced by intestinal bacteria (vitamin K)
Can be fat soluble (A, D, E, K); water soluble (B, C)
Excess vitamins
> vit c - stomach inflammation
vit a - toxic during pregnancy
vit b - beriberi
Minerals
Inorganic nutrients
Components of co-enymes, some vitamins, haemoglobin, organic molecules
Major minerals
major minerals >100mg/day (calcium, magnesium, sodium, potassium)
Trace minerals
trace minerals < 100mg/day (selenium, zinc, copper)
Minerals: uses in the body
- membrane and action potential
- adds mechanical strength to bones and teeth
Mineral deficiency
> iron - anaemia
potassium - muscle weakness, abnormal heart function
iodine - goitre (hypothyroidism
