Download Life with Carbon

Life with Carbon
4-3
• Food provides organic compounds  cells
use, change & store
• 4 classes of organic compounds:
– Carbohydrates
– Proteins
– Lipids
– Nucleic acids
• Carbs, proteins, lipids = nutrients
• Nutrients
– Provide energy
– Raw materials the body needs to grow, repair, function
• Carbohydrates
– Energy rich organic compound
• Made of carbon
• Hydrogen
• Oxygen
– Carbo = carbon
– Hydrate = combined with water
– Simple carbs
• Sugars
– Glucose (C6H12O6) – blood sugar circulated to all body parts
through blood (see p 137 figure 15)
– White sugar = sucrose (in cookies, drinks etc)
» More complex – C12H22O11
– Complex carbs
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Larger molecule that simple carbs
Polymer
One molecule may have hundreds of carbon atoms
Starch & cellulose – polymers built from glucose – are
arranged differently
– Different compounds – body uses each differently
• Starch
– Stored in plants
» Food made from wheat grains
• Rice, potatoes, veggies
– Digestion – chemical reactions that break large molecules
such as starch into smaller molecules
» Body breaks apart large starch molecules into indiv.
Glucose molecules
• Body breaks glucose molecules releasing energy
– Cellulose
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Plants strong roots & stems
High in most fruits & veggies
Body cannot break down cellulose
NOT a source of energy
Keep digestive tract active & healthy
– FIBER
• Proteins
– Polymers formed from amino acids
• Amino acids = monomer – building block of protein
– Muscles, hair, skin & fingernails
• Birds feathers, spider web, fish scales, rhino horns
• Chains of amino acids
– Different proteins are made from different
sequences of amino acids
– See fig. 17 p 141
– Each amino acid has a carboxyl group (-COOH)
• Where the acid portion comes from
• An amino group with structure –NH2 is = source of
amino half of the name
• Food protein become your proteins
– Meat, fish, eggs, milk, beans = good proteins
• Lipids
– Energy rich compounds made of carbon, oxygen,
hydrogen
• Fats, oils, waxes & cholesterol
• Release twice as much energy in body as carbs.
• Mix poorly with water
– Fats & oils
• Each fat or oil made from 3 fatty acids & one alcohol
named glycerol
– Fats – solids at room temp
– Oils – liquids
• Saturated - no double bonds between carbon atoms
• Unsaturated fatty acids found in oils
– Monounsaturated oils – fatty acids 1 double bond
– Polyunsaturated – fatty acids with many double
bonds
• Saturated fats – HIGHER melting points than
unsat. Oils
• Cholesterol – waxy substance found in all
animal cells
– Body needs cholesterol to build cell structures
– To form compounds that serve as chem.
messengers
– Not a source of energy
– Body produces cholesterol from nutrients
• Foods that come from animals
– Cheese, eggs, meat
– Foods from plant sources, such as vegetable oil, never contain
cholesterol
• Excessive level of cholesterol can contribute to heart
disease
– Limit intake of saturated fats too!!
• Nucleic Acids
– Very large organic molecules made up of carbon,
oxygen, hydrogen, nitrogen, & phosphorus
• DNA – deoxyribonucleic acid
• RNS – ribonucleic acid
– See p 143
• Nucleotides
– Building blocks of nucleic acids
• DNA & proteins
– Differences among living things depend on the
order of nucleotides in their DNA
– Living things differ due to DNA
• Other compounds in foods
– Your body needs
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Vitamins
Minerals
Water
Salts
– Vitamins
• Organic compounds – helper molecules
– Vitamin C – ascorbic acid – keeps skin & gums healthy
– Vitamin D – bones & teeth strong
– Minerals
• Not organic compounds
– Calcium, iron, iodine, sodium & potassium
• Water
– Not an organic compound
– Body needs for survival
• Only survive a few days without water
– Makes up most of your body’s fluids – 90% of the
liquid part of blood
– Many chemical reactions such as breakdown of
nutrients take place in water
– Wastes from cells dissolve in blood are carried
away