chapter 15 - structure and bonds in food

Question 1

amino acids

Answer 1

monomer molecules used to build proteins

Question 2

2-amino-acid structure

Answer 2

central C
- carboxyl group
- amine group
- H atom
- R group (1/20)

Question 3

side chains

Answer 3

non-essential - 11/20 humans can synthesise
essential - body can’t synthesise them and must be included in the diet

Question 4

functional groups

Answer 4

carboxyl group - allows amino acid to behave as an acid in high pH (H+ is donated, negatively charged)
amine group - allows amino acid to behave as a base in low pH (accepts H+ ion from solution)

Question 5

zwitterion

Answer 5

in neutral solution,a mino acid will both gain and lose an H+
has both a positive and negative end
neutral pH is dependant on side chain (isoelectric point)

Question 6

condensation polymerisation

Answer 6

the formations of polymers by condensation reaction
occurs between two functional groups

Question 7

bonds of proteins, triglycerides, polysaccharides

Answer 7

proteins
- peptide linkage (amide) (CONH)
- formed between amine (NH2) and carboxyl (COOH)
triglycerides
- ester (COO)
- formed between hydroxyl (OH) and carboxyl (COOH)
polysaccharides
- glycosidic link (ether) (O)
- formed between 2 hydroxyls (OH)

Question 8

protein structure

Answer 8

primary structure
- type, number, sequence of amino acids
- covalent bonding
secondary structure
- chains coils up due to hydrogen bonds between different parts of the chain
(alpha-helix and beta-pleated sheets both have hydrogen bonds between N-H and O=C)
tertiary structure
- working shape of protein
- bonds between side chains
- every bonding
quaternary structure
- multiple polypeptide chains
- fully working shape

Question 9

triglycerides

Answer 9

fats and oils (lipids)

Question 10

equation of triglycerides

Answer 10

1 glycerol + 3 carboxylic acids = 1 triglycerides + 3 waters
C3H5O3H3 + 3CnH2n+1COOH = CnH2n+1COOCH5 + 3H2O

Question 11

types of fats

Answer 11

• saturated fats
• mono-unsaturated fats
• poly-unsaturated fats

Question 12

saturated fats

Answer 12

• only c-c single bonds
• unhealthy
• general formula - CnH2n+1COOH

Question 13

mono unsaturated fats

Answer 13

• only one c-c double bond per fatty acid
• healthy
• CnH2n-1COOH

Question 14

poly unsaturated fats

Answer 14

• multiple c-c double bonds
• minus 2 H for every double bond
• omega denotes position of closest double bond to the end (functional group denotes start)
  linolenic acid - omega 3 fatty acid
  linoleic acid - omega 6 fatty acid

Question 15

melting point

Answer 15

saturated fats have a higher melting point than unsaturated
- double bonds create kinks in chain
- prevent them from packing closely together and reduce strength of dispersion forces

Question 16

hydrogenation

Answer 16

reducing number of double bonds in polyunsaturated fats increasing melting point
- fat + hydrogen and nickel catalyst (addition reaction)
trans- fatty acids
formed when hydrogenation id not complete and causes unsaturated trans configuration
more harmful

Question 17

essential and non-essential fatty acids

Answer 17

non-essential - can be converted into other fatty acids if needed in body
essential - need them for specific functions and cant be made another way
(linoleic, linolenic)

Question 18

carbohydrates

Answer 18

primary energy source
- monosaccharides (glucose, fructose)
- disaccharides (sucrose)
- polysaccharides (starch cellulose, glycogen)

Question 19

monosaccharides

Answer 19

CH2O
simplest sugars
OH makes it soluble

Question 20

disaccharides

Answer 20

formed through condensation reaction between hydroxyl groups on adjacent monosaccharides and forma a glycosidic link

Question 21

aspartame

Answer 21

significantly sweeter than sugar per g
less is needed

Question 22

polysaccharides

Answer 22

three types of polysaccharides
- starch
- cellulose
- glycogen

Question 23

starch

Answer 23

• store energy in plants
• made up of long alpha glucose chain
• two forms (amylose (straight chain, amylopectin (branched chain))
  little branching making it slow to be hydrolysed (every20-24)

Question 24

cellulose

Answer 24

• structural molecules in plant cells
• make from alpha and beta glucose
• cannot be digested (hydrolysed)

Question 25

glycogen

Answer 25

• molecules animals use to store energy
• made up of alpha glucose
• more branched (every 7-11)
• branches make it easier fro enzymes to hydrolyse ether linkage and release glucose for respiration, making energy more accessible

Question 26

vitamins

Answer 26

• organic micronutrients
• vital to normal functioning of animals metabolism
• cannot be synthesised
• water- soluble or fat soluble

Question 27

water soluble vitamins

Answer 27

• depend on large number of hydroxyl groups present
• vitamin C and B
• excreted in urine if not needed
• regular part of diet

Question 28

fat soluble vitamins

Answer 28

• depend on dispersion forces to dissolve
• vitamin A,D,E,K
• build up in fatty tissue of body
• hypervitaminosis