Chemistry U4AOS2

Digestion

Chemical

Mouth

Mechanical

Stomach

Metabolism

Small Intestine

Digestion

breaking down covalent bonds, hydrolysis, breaking down macro molecules into single molecules to be later absorbed into bloodstream

breaking down and absorption into the bloodstream via small intestine

enzymes break bonds and increase rate

increases surface area

mechanical = chewing (all nutrients)

mechanical = churning muscular bag (all nutrients)

mechanical = bile from gall bladder mixes with fats to emulsify (becomes smaller molecules ) ( only fats)

chemical = amylase mixes with long chain carbohydrates to break down to sugar (only carbohydrates)

chemical = protease mixes with protein in acid environment to break down to amino acids (only protein)

chemical = amylase, protease and lipase (from pancreas) mix with food to break down to glucose, amino acids and glycerol & fatty acids (all nutrients)

Proteins

Enzymes

Triglycerides

Carbohydrates

General formula NH2-CH(R)-COOH

Each a-animo acid has a central C, NH2 group, COOH group and a R group (difference for each)

There are 9 essential amino acids that must come from our diet as we don't produce them ourselves

NH2 can act as a base in an acidic environment and accept a H proton

Polymers of amino acids

COOH can act as an acid in a basic environment and donate a H proton

At a neutral pH both COOH and NH2 can act as an acid and base respectively to create a neutral charge (zwitterion)

Structures

Digestion of proteins

Calorimetry

Primary - amino acid chain (peptide links)

Secondary - a-helices and b-pleated sheets, caused by the polarity of R groups and H-bonds

Tertiary - folding of whole protein to form globular proteins (each with a unique shape, all bond types present

Quaternary - multiple protein chains together

By hydrolysis to convert proteins into amino acids

Amino acids are then reformed to make new proteins (condensation reaction) or broken down further to form urea, as the body cannot store amino acids

Enzymes are proteins which catalyse almost all chemical reactions in the body

Can increase the rate of a reaction by lowering the activation energy

Can be denatured by high temperatures or extreme pH environments, causes protein to change shape and no longer function properly

They provide the body energy via cellular respiration

Types of Carbohydrates

Carbohydrates are made by plants through photosynthesis

Digestion of Carbohydrates

Made up of C, H and O, general formula = Cx(H2O)y

Monosaccharides

Disaccharides

Polysaccharides

Condensation

Hydrolysis

Monosaccharides (glucose) can be used to make new carbohydrates or it can be stored in the liver

removal of water, creates disaccharides and polysaccharides, formation of ether links/glycosidic bond between monomer units

addition of water, to form monosaccharides, breaking of ether links/glycosidic bonds

starch (amylose - linear and amylopectin - branched, energy storage in plants), glycogen (energy storage for animals, highly branched), cellulose (cannot be digested by humans)

sucrose, maltose

glucose, galactose, fructose

Made up of 1 glycerol and 3 fatty acids to produce 1 fat and 3 water molecules in a condensation reaction

Provide the greatest amount of energy per gram

Large macromolecules, not polymers, that are generally non-polar

Digestion of fats

Made up of C, H and O and belong to a large group called lipids

Types of Fats

Hydrolysis takes place in the small intestine

Bile emulsifies the fat to increase its surface area so the lipase can further break it down

Glycerol and fatty acids are then absorbed via the villi into the bloodstream where the fat reassembles by condensation

Excess fat is stored in the body in adipose tissue

Polyunsaturated

n(C=C) = C - H/2

Fats

Monounsaturated

Saturated

Oils

CnH2n+1COOH, all single C-C bonds

CnH2n-1COOH, one double C=C bond

CnH>2n-1COOH, more than one double C=C bond

solid at room temperature, saturated C-C bonds, packed tightly, higher melting point

liquid at room temperature, unsaturated C=C bonds, not packed tightly, lower melting point

Energy content of food

1 calorie = 4.184J, 1 Calorie = 1 kilocalorie = 4184J

1g of carbohydrate and protein provides 17kJ/g and 1g of fat provides 37kJ/g

Amount of heat produced by the combustion of 1g of food

Energy is provided to the body fastest by carbohydrates

Step 3: Link step 1 and step 2 to find energy released or absorbed (E = CF x delta T)

Step 4: Link E to moles per equation or grams (heat content = E/grams)

Step 2: Use calorimeter to do energy transfer experiment (find delta T)

Step 1: Calibrate calorimeter, chemical (CF = (n x delta H) / delta T), electrical (VIt / delta T)