food Flashcards
(75 cards)
1
Q
what are core food molecules and biomolecules
A
carbohydrates
proteins and enzymes
fats and oils (triglycerides)
vitamins
2
Q
carbohydrates
A
- Cx(H2O)y
- provide a source of energy, way of storing energy, structural material
3
Q
carbohydrates general structure
A
- dissacharides or polysaccharides are joined with a glycosidic link / ether group
4
Q
lactose monomers?
A
galactose and glucose
5
Q
sucrose monomers?
A
fructose and glucose
6
Q
maltose monomers?
A
2x glucose
7
Q
glucose vs fructose difference
A
glucose= in fischer projection there is an aldehyde group
fructose= ketone group on 2nd C
8
Q
determining mass of saccharide
A
180 x number of glucose = ___x__
18x( no. glucose- 1) =___y___
t/f x-y
9
Q
polysaccharide examples
A
starch - amylose and amylopectin
glycogen (alpha glucose)
cellulose (beta glucose)
10
Q
starch
A
- energy storage components of plants
-composed of alpha glucose
-two forms - amylose and amylopectin
11
Q
amylopectin
A
-crosslink bw glucose molecules - reaction bw OH groups on C1 and C6 sections
-less effective packing and decrease attraction bw OH groups - weaker H bond - high GI
12
Q
amylose
A
- linear polymer that properly packs effectively - strong attraction to OH groups - low GI
13
Q
amylopectin vs amylose
A
branching affects ability to breakdown
-amylopectin to break down faster
14
Q
glycogen
A
-energy storage structure in humans & animals
-alpha glucose
-highly branched
- convert glucose into glycogen and stored in liver& muscle cells
15
Q
cellulose
A
- structural material found in plants
-formed from beta glucose - tightly pack together - strength as plant fibre
- body = unable to break down & acts as dietary fibre
16
Q
artificial sweeteners
A
- similar sized to many common sugars but are significantlly sweeter than sugars
- require lower energy/ calorie diets to obtain same amount of sweetness
17
Q
aspartame
A
outcome of a reaction between aspartic acid, phenylalanone and methanol - is an artificial sweetener
18
Q
energy carbohydrates
A
most common source of energy - hydrolysed to form glucoes which undergoes respiration to form energy
19
Q
cellulose - indigestible carbs
A
- human body lacks necessary enzyme to catalyse the reaction
- considered a dietary fibre bc helps food pass through in bulk amounts and decreases risk of constipation, cancers etc.
- bodies have system to break it down but it passes through body before broken down into any nutritional value
20
Q
intolerances eg. lactose
A
lack sufficient amount of the enzyme lactase to hydrolyse the lactose sugar
-side effects - discomfort, bloating ,cramps, diarrhoea
21
Q
GMI definition
A
how quickly glucose is released in the bloodstream after consuming food
- low GI is slower than high GI
22
Q
HIGH GI HAS WHAT
A
AMYLPECTIN
23
Q
LOW GI HAS WHAT
A
AMYLOSE
24
Q
diabetes
A
- type 1 - doesnt produce necessary insulin
-type 2 - cannot produce quickly enoigh to match the release of glucose into the blood
25
fats and oil (triglycerides)
- ESTERS
-contain CHO
- formed in condensation reaction bw glyecrol and 3 fatty acids and forms triglyceride and water
- large relatively non polar - low solubility
26
unsaturated - mono or poly
C to C double bonds
27
saturated formuls - fatty acid
CnH2n+1COOH
28
monounsaturated fatty acid general form
CnH2n-1COOH
29
essential fatty acids
-fatty acids that the body cannot synthesise
- obtained from food / diet - omega 3 or 6 and need a good dietary balance
30
nonessential fatty acids
- body is capable of synthesising FA
31
omega 6 benefits
known to increase blood pressure, immune response and inflammation
32
omega 3 benefits
heart healthy effects
33
omega 3 or 6
depends on where the first c to c double bond is from the omega end (opposite COOH region)
34
trans fats
- unsaturated that are artificially produced - in hydrogenation (Ni catalyst and 15deg)
-resisted rancidity and desirable MP
35
rancidity - possible reactions?
-oxidative = O reacts near double bond
- microbial = bacterial action
- hydrolytic= hydrolysis to fatty acid and glycerol
36
rancidity
- fats and oils deterioate over time
- unsaturated fats are less stable bc more succeptible to oxidative rancidity
- deterioate food or smell
37
oxidative rancidity problems
lead to formation of unpleasant smelling and potential harmful short chain aldehydes and ketones - unpleasant smells & flavours
- most common = autooxidation
38
how are vitamins distinguished
water soluble or fat soluble
39
water soluble vitamins
- consumed regularly
- high proportion of OH groups that form H bonds with water and dissolve - pass through body quickly
40
fat soluble vitamins
long hydrocarbon chains - low OH groups so stronger dispersion forces compared to few H bonds - absorbed by the body
41
methods to slow rancidity
- vacuum packaging
- fill containers to the lid
- store food in dark and cold
- antioxidants
42
antioxidants
- eg. vitamin C
- natural or synthetic and will slow down oxidation and prevent food from spoiling
- donate an e- to free radicals in order to interupt propagation of free radicals - increase rancidity
43
vitamins essential or not
non essential - vitamin D
essential - other vitamins
44
vitamins
- perform variety of vital roles including action as a coenzyme, aiding the immune system or preventing hamrful chemical reactions (antioxidant)
45
difference bw carbohydrate and triglyceride in terms of structure
fatty acid has only 2 oxygen atoms whereas carbohydrates have lots of oxygen
46
amino acids
CHONS
47
zwitterions
dipolar ions
- have no overall net charge
- contains a negative and positive charge/ region
-exist at neutral pH (7)
48
in basic environment a zwitterion
gains H+ on the N region - net negative charge
49
in acidic environment a zwitterion
forms a NH3+
50
what links a dipeptide
amide or peptide linkages
51
primary protein structure
- amino acid sequence in the peptide /protein chain
- strong covalent bonds linking each aa at amide link
52
secondary structure protein
- forms H bonds with different sections of the protein chain -H attached to N and the O attached to C = H bonds
- primary structure folded into alpha helix or beta pleated sheets
53
tertiary protein structure
- unique 3d shape of the protein (globular)
-this determines its unique function
- driven by the side chain/ R groups
-bonds that keep structure intact include covalent bonds, dp-dp, H bonds etc.
54
quaternary protein structure
- 2 or more polypeptides joined together
eg. haemoglobin
55
digestion of proteins
- aa are absorbed in the bloodstream and used to build up new protein
-aa not used are broken down in liver (deamination) where NH2 is converted into ammonia which is converted to urea and excreted or used to synthesise other proteins
- remainder proteins composed of CHO=converted to glucose(energy), fat(storage) or aa
56
hydrolysis of protein
CHANGE PRIMARY STRUCTURE
covalent bonds are broken in presence of water and specific enzymes
57
denaturation of proteins
- change in 3D structure (tertiary) or function of molecules like proteins at extreme pH or temperature
- disrupt R groups
-can be reversible and irreversible depending on protein+ ability to reconfigure its 3D shape
58
enzymes - role and function
- biological catalysts
-catalyses chemical reactions in the body which is necessary to sustain life otherwise metabolic cellular processes= too slow
- provides alternate reaction pathway that lowers the activation energy
- can be measured by noting ROR
59
enzyme action
- reactant/substrate binds to enzyme at active site - it will be S+C in terms of shape and charge
- not consumed
60
lock and key enzyme model
substrate perfectly fits into enzyme , like a lock
- after successful binding forms an ESC and catalyse reaction = catabolism or anabolism
61
enzyme induced fit
- shape of the substrate X perfectly complimentary to shape of as.
- to overcome this as adjusts to become S+C to substrate
- afterwards the as. returns to its original shape/ remains unchanged
62
enzyme activity definition
amount of substrate converted to product per unit time
63
denaturation of enzymes
-temp - increase KE makes molecules vibrate more rapidly so H bond , interaction bw R groups and arrangement of protein is disrupt
-pH -change the 3D shape of protein
64
enzyme - enantiomers
- only catalyses a reaction w one enantiomer bc the as is S+C - different arrangement of atoms - specificity
65
coenzymes
-do not catalyse a reaction
-temporarily bind to as of enzyme as they are modified to suit the shape of the substrate
- serve as a carrier of groups of atom/ e-
66
calibration factor electrical
CF= VxI xT
-------------
delta T
67
calibration factor chemical
CF = E/ delta T
68
poorly insulated calorimeters need what
to extrapolate data back to time calorimeter was turned on
69
what is a condition for bomb calorimetry
high pressure to ensure reaction goes to completion
70
calorimetry
method where the heat released or abosrbed is measured
71
random errors for calorimetry
- not all food combusted
- incomplete combustion
- temperature change = inaccurate
72
systematic error for calorimetry
- calirometer calibrated incorrectly
- measurement to calibrate eq. = incorrect - affect energy calc.
73
types of calorimeter
solution and bomb
74
bomb calorimetry
-measures HoC of chemical reactions that involve gaseous reactants or products
-exothermic
-measures heat content of fuels and foods
75
solution calorimetry
- calculates energy transferred in a chemical reaction
- measure heat of solution/neutralisation
