Unit 4 AOS 2 Flashcards
What is food needed for in the body
energy, growth, regulating body processes
What are the major food groups needed for the body
proteins, carbohydrates, fats and oils, vitamins and minerals
What are proteins needed for
growth, repair, immunity, transport of molecules,
Examples of what proteins are used for
hormones, enzymes, cellular structures (e.g. cell membrane, muscles), to transport molecules in the body, antibodies
What are carbohydrates needed for
to store and provide energy, functioning in nervous system
What are fats and oils needed for
insulation, to store some vitamins, to provide energy, in cell membranes
Define proteins
large molecules composed of one or more long chains of amino acids.
What are the monomers of proteins
amino acids
How many amino acids are there in the body
20
Can all these 20 amino acids be made by the body
no
How do we get amino acids that can’t be made in our body
through our food
What are essential amino acids
amino acids that cannot be synthesised by animals from materials in their diets and therefore must be supplied directly in the diet.
What elements make up amino acids
C, H, O, N and sometimes S and P
What are the amino acids used to synthesise proteins in the body called
2-amino acids or alpha amino acids
What is the structure of amino acids
CH, R, COOH, NH2
What properties can the R chain have
polar, non-polar, acidic or basic
Are amino acids soluble and why
they are soluble as they can form H bonds with water
Can amino act as acids, bases or both
both
What can amino acids act as
dipolar ions/zwitterions
What is a zwitterion
contain equal positive and negative charges
What does an amino acid look like as a zwitterion
NH3+ and COO-
When does an amino acid act as a zwitterion
pure solid state and in aqueous solutions in neutral pH, e.g. water
What will happen to amino acid in acidic environment
will act as base and so will have NH3+ with COOH
What will happen to amino acid in basic environment
will act as an acid and so will have NH2 and COO-
What is a sequence of amino acids called
a peptide chain
Between what molecules is the bond in a peptide chain
between the CO and the NH2 (O=C-N-H)
What is the bond in a peptide chain called
peptide bond
What is the name of the link between the C and the N
amide linkage
When is a polypeptide called a protein
more than 50 amino acids/ molar mass >5000gmol-1
How do you name a polypeptide (3)
by the sequence of amino acids from which they are made - which amino acid it derived from and put the abbreviation and then just put a dash to the next one, and it is written from left to right
Where is the N-terminus in a polypeptide chain
left side
Where is the C-terminus in a polypeptide chain
right side
What is the amino acids components of a polypeptide called
amino-acid residue
Define polypeptide
many amino acid residues bonded together.
Define primary structure
the order of amino acids in a polypeptide chain
Define secondary structure
structure formed folding of the polypeptide chain due to hydrogen bonding between carboxyl and amino groups in a protein molecule.
Important to note about secondary structure
the hydrogen bonding is at different positions of the chain
What causes alpha helices
H bonding between partially partially positive NH group and the partially negative COOH
What causes beta pleated sheet
H bonding between peptide links
Define tertiary structure
3D structure formed from side-group interaction, including hydrogen bonding, ionic bonding, dipole–dipole interactions and disulfide bridges
Define quaternary structure
multiple polypeptide chains joined together
Define denaturation
loss of structure or function of a protein
What causes denaturation
pH changes and heat
Why do pH changes and heat cause denaturation
damages bonds in polypeptide
Can denaturation be partial + why
yes if it doesn’t break primary covalent (peptide) bonds but just secondary and tertiary bonds e.g. warm milk
Define enzymes
biological catalysts that speed up reactions through providing an alternate pathway for the reaction which requires less energy
What is the general suffix of enzymes
ase
Examples of enzymes that don’t end in ase
trypsin, pepsin
What are the two types of proteins
globular and fibrous
What is the solubility of globular/fibrous
globular is soluble and fibrous is insoluble
What is the lock and key model
the specific shape of the active site fits exactly the shape of the substrate it will act on, hence will only act on that substrate.
What is the induced fit model
the specific shape of the active site of the enzyme varies slightly from that of the substrate and the two fit only after contact when the substrate induces a complementary shape at the active site of the enzyme.
Define active site
A region on an enzyme that binds to a protein or other substance during a reaction.
Define substrate
The substance on which an enzyme acts.
Do enzymes take part in a reaction
no
Define coenzyme
organic non-protein molecules required to temporarily and loosely bind with the protein molecule to form an active enzyme.
Are coenzymes specific
not always
Define hydrolysis
the chemical breakdown of a compound due to the addition of water.
What is the general formula for carbohydrates
Cx(H2O)y
What elements do carbohydrates contain
C, H, O
What is the monomer for sugars
monosaccharides
Are carbohydrates soluble and why
due to the multiple -OH groups, they are highly soluble in water because can form H bonding
Do all monosaccharides have the same formula
yes (and so are isomers)
Can monosaccharides be linear
yes, but most are cyclic
What bonds are between sugar molecules
ether/glycosidic links
Where does the bond occur between monosaccharides
between the OH groups (and H2O is lost)
What polymers are in starch
amylose and amylopectin
Is amylose branched or linear
linear
Is amylopectin branched or linear
branched
What type of isomers are glucose and galactose
stereoisomers
What does amylase break starch into
maltose
What does maltase break maltose into
glucose
What is another name for cellulose
fibre
What does GI stand for
glycaemic index
What is GI
A figure representing the relative ability of a carbohydrate food to increase the level of glucose in the blood
Examples of food high GI
lollies, chocolate, ice-cream
Examples of food low GI
brown rice, wholemeal bread, pasta
How is glycaemic load calculated
grams in serve * GI /100
What is the standard for GI
glucose at 100
Why are fruits low GI
because fructose has to be converted to glucose (takes time)
What is aspartame
artificial sweetener
What are glucose blood levels measured in
mmol-1 (mM)
What is called when there is too much blood glucose
hyperglycaemia
What is it called when there is too little blood glucose
hypoglycaemia
What are the three categories of carbohydrates
monosaccharides, disaccharides, polysaccharides
What are the two types of glucose
alpha and beta
Where is the OH located on alpha glucose
bottom
Where is the OH located on beta glucose
top
How many monomers to make polysaccharide
more than 10
What are ogliosaccharides
Three to ten monosaccharides bonded together.
What is the general suffix for sugars
ose
How many times sweeter is aspartame compared to glucose
200 times sweeter
Are amylose/amylopectin soluble/insoluble
amylose is soluble and amylopectin is insoluble
General formula for glycogen
(C6H12O5)n
Properties of glycogen
soluble, highly branched, alpha glucose
Properties of starch
slightly soluble, moderately branched, alpha glucose
Properties of cellulose
insoluble, unbranched, beta glucose
Types of disaccharides (3)
lactose (galactose + glucose), maltose (glucose + glucose), sucrose (glucose + fructose)
Types of polysaccharides (3)
starch, cellulose, glycogen
What are vitamins
organic compounds that are needed in minute quantities on a regular basis as part of a healthy diet.
How many vitamins are required by body
13
Can we make vitamins
no, except for Vitamin D
Two categories of vitamins
fat soluble and water soluble
Examples of fat soluble vitamins
D, A, K, E
Examples of water soluble vitamins
B, C
Can water soluble vitamins be stored
no
Where are fat soluble vitamins stored
in fat (adipose tissue)
What is the only non-essential vitamin
Vitamin D
What are vitamins needed for
regulating metabolic processes e.g. producing energy, supporting the immune system
Are fats solids/liquids
solids
Are oils solids/liquids
liquids
What enzyme digests fats
lipase
What is the formula for a fatty acid with 0 double bonds
CnH2n+1COOH
What is the formula for a fatty acid with 1 double bond
CnH2n-1COOH
What is the formula for a fatty acid with 2 double bonds
CnH2n-3COOH
What are fatty acids
long-chain carboxylic acid containing an even number of carbon atoms.
Saturated fatty acid
no double bonds
Mono-unsaturated fatty acid
1 double bond
Polyunsaturated fatty acid
more than 1 double bond
What is the link called in a fatty acid
ester link
What are the essential fatty acids of the body
alpha-linolenic acid (ALA) and linoleic acid (LA).
What are essential fatty acids also called
omega fatty acids
What is omega 3 fatty acid
alpha-linolenic acid
What is omega 6 fatty acid
linoleic acid
What is the order of energy sources in body
carbohydrates, then fats then proteins
Are saturated or unsaturated more likely to go rancid
unsaturated as less stable
What is the omega group in fatty acid
methyl
What emulsion
breaking down fats (bile)
What is calorimetry
Method used to determine the changes in energy of a system by measuring heat exchanges with the surroundings. It is the measurement of the amount of heat released or absorbed in a chemical reaction, change of state or formation of a solution.
What is a calorimeter
Apparatus used to measure heat changes during a chemical reaction or change of state.
What are different types of calorimeters
bomb calorimeters and solution calorimeters
Formula for energy in calorimetry (2)
E = V * I * t or E = n * delta H
What is metabolism
chemical processes that involve breaking down and building different substances
What is calibration factor
the amount of energy that is required to change the contents of the calorimeter by 1 degree
Formula for calibration factor in calorimetry
Cf = E/delta T
Unit for calibration factor
J / degrees Celsius
Is calories with a lower case c or upper case c
lower case c
Is it usually cis or trans in unsaturated fatty acids
cis
What is the functional group of monosaccharides
OH
What type of double bond (cis or trans) occurs in nature
cis
Can trans bonds occur in nature
no
