Topic 1 Flashcards
1
Q
what is the theory of evolution?
A
all organisms on earth from ine common ancestor, and that the organisms have changed and diversified overtime
2
Q
what do some organisms share?
A
biochemistry
3
Q
what do all organisms contain?
A
the same group of carbon based compounds (which is used as evidance for evolution)
4
Q
what are polymors
A
complex moleculs composed of long chains of monomers joined together
5
Q
what are monomers
A
small basic molecular units that form a polymer
6
Q
what procces is used to make a polymor?
A
condensation reaction
7
Q
what does a condensation reaction do?
A
forms chemical bonds between monomers( realising molecule of water)
8
Q
what is the procces used to break polymors?
A
hydrolisis reaction
9
Q
what does a hydrolisis reaction do?
A
breaks chemical bonds between monomers using a water molecule
10
Q
what are monosaccharides?
A
contains elements C, H , O
-are the simplest sugers
-monomers
-composed withon a carbohydrate
-soluble
-affect osmotic potential
-sweet/crystalline
-identified with benedict solution
11
Q
examples of monosaccharides?
A
glucose, fructose, galactose
12
Q
what is glucose?
A
a hexose suger
-a monosacharide with 6 carbon atoms in each molecule
-they are alpha and beta glucose which are isomers
13
Q
what are isomers?
A
molecule with same molecular formula as eachother, but with atoms connected in different way
14
Q
What are Disaccharides?
A
formed when two monosacharrides join together via a condensation reaction
-then has a glycosdic bond firm between the two monosuccharides
examples: sucrose and galactose
(soluble, affect osmotic potential, crystalline/sweet, identified with benedicts solution)
15
Q
what do reducing sugers contain?🥲
A
monosaccharides and some disacharides
16
Q
how do you test for reducing sugers?
A
{benedicts test}
add benedict reagent to sample & heat in water bath that has been brought to boil
if its positivetgen forms red coloured precipitate of copper oxide
17
Q
what is a coloured precipitate?
A
solid particles suspended in the solution
18
Q
what does it mean if the colour further changes?
A
there is a higher concentration of reducing sugers
19
Q
what is a more accurate “ QUANTATIVE” method to measure concentration?
A
1, filter solution to obtain precipitate
2, dry filter paper with precipitate slowly in warm oven
3 weigh dried precipitate. to find the mass of precipitate
filter solution then weigh preipitate to measure its mass, which shows the absorbance of remaining benedicts reagent
20
Q
how do you test for non reducing sugers?
A
(involves breaking sugers down into monosaccharide)
- get new sample of test solution
- add hydrochloric acid then carefully heat it in water bath that has been brought to boil for 5 min
- neutralise sample by adding hydrogen carbonate, then heat sample with benedicts reagent for 5 min( test with pH paper if alkaline as Benedict reagent not work in acidic conditions)
–_+if positive.then forms coloured precipitate(orange, brown)
21
Q
what are polysaccharides?
A
moleculs made from large numbers of monomers (monosaccharides)
that are formed when more than too monosaccharides are joint together by a condensation reaction
(insoluble, dont affect osmotic potential, not crystalline/sweet, identified with iodine dissolved in potassium iodide solution)
22
Q
what are examples of polysaccharides
A
-starch
-glycogen
-cellulose
23
Q
what is starch?
A
excess glucose which is stored,
-polysaccharide
-branched form has many ends, so monomers released quickly
so it can be broked down when plant needs energy some more glucose for cells
(when hydrolised forms alpha glucose, usefal in respiration)
24
Q
what are rhe two types of starch?
A
-amylose
-amylopectin
25
what is amylose?
is a long branched , Straight, chain of alpha glucose.
it had glycosidic bonds that have angles which give it a coiled structure, like a cylinder. (called helical shape)
it is compact anf good for storage as it can fit into small spaces ( starch grains surrounded by amyloplast)
-makes up 80% of starch
-all are 1-4 carbon bonds
but only has two ends, so slow hydrolysis
(hydroxyl group point inwards, make curls) has hydrogen bonds
26
what is amylopectin?
long branched chain of alpha glucose
-20% stored starch in plant
-has 1-6 and 1-4 (link to branches carbon bonds)
has side branches that allow enzymes(which hydrolysis the molecule[amylipectin]) to get at glycosidic bonds easily, meaning glucose can be released quickly
=faster hydrolysis (also make it compact)
more terminal glucose moleculs
27
why is starch good for storage?
-it is insoluble in water, so doesnt affect water potential. meaning water wont enter cell, avoiding swelling of cell, -nor diffuse out cell
-compact, stored is small spaces
-hydrolysed forms alpha glucose. That’s easily transported
-has many ends which allows enzymes to act on starch to release glucose monomers easily
28
what are the monomer in maltose, sucrose and galactose?
-maltose(glucose + glucose)
-sucrose( glucose + fructose)
-lactose ( glucose + galactose)
29
what is a polar molecule?
-where the electrons spend more time in one position of the molecule. making region negativly charged.
-creating an uneven distrubution of charge.
30
what is hydrogen bonding?
-involves positive and negative charged regions that attract eachother.
which forms wesl electrostatic bonds, (that altars physical properties) (between atoms)
31
what is metabolsim?
the name of all chemical procces
32
what is the definition of mole?
the unit for measuring amount of a substance (referred to as molecular mass)
33
what is a molar solution?
-contains one mole of solute in each litre of solution
34
what is glycogen?
-is a carbohydrate storage product for aninals and is stored as small gycogen granules in muscles and liver
-branched 1-4 and 1-6 carbon
-polysaccharide( so insoluble [not diffuse out of cell])
-has lots of branches, so more rapidly hydrolysed glucose monomers.
35
what is cellulose?
-made of beta glucose
- **has long straight chains that run parralel to eachother and crosslinked by hydrogen bonds. lots off beta glucose give it its strength**
- there grouped together to form microfibilis. that are arranged in parralel groups called microfibres
[provide rigidity to plant cell]
36
what does the fibres in celloluse cause the plant to do?
--prevents cell bursting as water enters by osmosis. exerting inwards pressure that stops further influx of water.
--so cells become turgid and push against eachother--HENce make non woddy plant parts semi rigid-- increasing surface area for photosynthesis
37
how do you test for starch?
iodine test
38
how do you complete the iodine test?
1-place 2cm/ drops of sample into test tube
2- add two deops of iodine solution and shake
3- starch is present if there is a blue/blacl coloration
39
what are non reducing sugers?
sugers (disaccharides) that need to be hydrolised inti monosaccharied
40
what is the key property that determines a reducing sugars?
If a sugar is able to donate electrons to another chemical[Benedict’s reagent] (can be oxidised)
41
what is a pentose suger?
has 5 carbon atoms attatched to molecule/glucose
42
what is a hydroxyl group?
consist of oxygen atom with two lone pairs bonded a hydrogen
43
what other Quantitive methods can you use to test qauntity of reducing sugers?
-colorimeter: shines beam of light through sample, the more copper sulfate in Benedict’s reagent used up, (more oxidation, electron donated to copper sulfate) less light is blocked(so is absorbed) and more transmitted. Which then the photo-electric cells pick up the light passed through (make sure sample is rescted with benedict)
-biosensors: used to give quantative measurmrnt of glucose by using immobalised enzymes. That can oxidise glucose, producing a charge turned into electrical signal by transducers that can then be processed to digital reading
44
what is chittin?
-polysaccharide
-has straight chain of beta glucose monomers which parallel to eachother. create intersheet hydrogen bonding. making it insolube in water. so act as water barrier against dehydration on expskeloton. preventing soft, delicat tissue getting dry. making it strong
-contains a acetamid group . which consist of N-acteylglucosamine, which is an essential structural component
-stronger than celloluse
-in cell eall of funghi and exoskeloton of arthropods
45
what are lipids?
-contain carbon hydrogen and oxygen
-can be solid at room temperature (fat)
-can be liquid at room temperature (liquid)
-insoluble in water, (oil repels water to make animals waterproof)
-solible in organic solvents like achohok and ocetone
46
what are the roles of lipids?
-when oxidised, can provide twice amount of energy as carbohydrates when same mass
-release valuable water(repels water in body, waterproof) (insoluble)
-help retain heat in body, are slow conductors of heat and stored beneath body surface
-[act as electrical insulator in mgelin sheath around nerve cell]
- fat stored provides protection around delicate organs
47
what are triglycerides?
has three fatty acud combined with glycerol. each fatty acid forms ester bond with glycerol
-all contains carboxyl group with hydrocarbon chain attatched
-is hydrolysed into glycerol and fatty acid which is used for respiration
-reduce mass carried by humans
-most energy per unit of mass kf any storage molecule
48
what are the 3 types of triglycerides?
saturated
monounsaturated
polyunsaturated
49
what are saturated triglycerides?
-has no carbon-carbon double bonds.
carbona are linked to maximmum number of hydrogen atoms
(molecule compact and straight)
are solids at room temperature
are fats
50
what are monounsaturated triglycerides?
they contain a single bonds of carbon
are oils
liquid at room temperature
the fatty acud tails bend, and fatty acids are further apart due to weak intemolecular forces= liquid formation
51
what arwhat are polyunsaturated triglycerides?
contain more than one double carbon bond
contain a fatty acid tail, which make fatty acuds further apart due to weak internolecular forces. forming liquid
52
what are the structural properties of triglycerides?
-(good energy source)contain high ratio of energy-storing carbon-hydrogen bonds to carbon atoms
-(good storage) has low mass to energy ratio. so enrrgy stored in multiple small volumes
-(not affect water potential) are large non polar molecules
-(good water source) has high ratio of hydrogen to oxygen atoms, so when oxadised produce lots of water
53
How do you test for lipids?
By the emulsion test
54
What is the emulsion test?
Use dry, grease free test tube which has 2cm sample and 5cm ethanol
-then shake thoroughly to dissolve sample
-add 5cm of water & shake
-if it is a milky white emulsion present. Then lipid present
55
If you use just water for the emulsion test, the. What color will it appear?
Remain clear (transparent)
56
Why does a cloudy color form from the emulsion test?
Light passing through emulsion is refracted as passing from oil droplet to water droplet
57
Why are phospholipid heads hydrophilic?
The hydrogen ions dissociate from the oxygen when phospholipids are surrounded by water (so donate H+ ions)
So the phosphate group creates a negative charge (o-)
58
What are the different arrangements phospholipid molecules can be?
bilayer
- liposomes
- Micelles
59
What are micelles?
Contain fatty acid in centre and head on outside. Are in circular shape (3D). Transport fats/lipids in blood
60
What are liposomes?
They contain heads on outside and close on inside to create and empty space in the middle. Can transport Lipo-protiens
61
Why are phospholipids good electrical insulators?
Contain myelin sheath and are partially permeabile
62
What are amino acids?
•monomers that combine to make polypeptide
(100 amino acids, 20 occur nationally in proteins in all living organisms, evidence for evolution) (organic molecules, have C ,H ,O)
-contains central carbon atom attached to four different chemical groups
•amine group (-NH2)
•carboxyl group (-COOH) acidic group
•hydrogen atom (-H)
• R (side) group (where 20 naturally occurring proteins differ (can contain sulphur, be hydrophobic/philic change size,
63
What are peptide bonds?
Amino acid monomers combining to form dipeptides via a condensation reaction
Process: combine (-OH) from carboxyl group with (-H) from amino group to produce water
)
Which are linked by peptide bind between carbon atom on carboxyl group (C=O) and nitrogen amino group (NH) atom, (is called amide)
The sequence repeated is called polypeptide backbone
-can be hydrolyzed with water
(Protease is a catalyses for reaction)
64
What are primary structures of proteins?
-Number and order of different amino acids
Amino acids join together via polymerization, creating polypeptide. ( sequence of amino acids) determined by DNA
-[are limitless number of possible conformations]
-only has peptide links
-determines protein final shape and function as R group determines 4 type of cross links that can be made. (shape specific to function)
65
What are secondary structures of proteins?
The -NH group that has a positive charge on polypeptide and points to N- terminal is attracted to the -C=O group that has a. Negative charge on polypeptide and points to C-Terminal form weak hydrogen bond (only cross links in structure). (Add strength)
Causes polypeptide chain to twist into 3D shape, providing polarity
(Alpha helix)
(Beta pleated sheets) chain form parallel to each other, with dipole-dipole interactions
66
What is the tertiary structure of proteins?
And alpha helix of secondary protein structure twisted & folded to give complex, specific 3D structure of each protien.
_Is maintained by different bonds:_
-disulfide bonds: fairly strong and therefore not easily broken. Link residues
-Ionic bonds: formed between carboxyl & amino acid group. (Not involved in peptide bonds) weaker than disulfide bond and easily broken by change in pH (Between charges)
-Hydrogen bonds: in large amounts but easily broken
-Van Der walls/hydrophobic interaction
(3D shape make it distinctive and help function)
——-
Bonds folded differently to form protein domains
——
Non polar side chain entropically driven together in aqueous environment, to limit disruption of hydrogen bonds) HYDROPHOBIC COLLAPSE
(Structure more affected by temperature and PH as cross links can be easily broken
(Exp:enzymes)
67
What is a Quaternary Structure of Protiens?
•complex molecule containing varied polypeptide chains or subunits linked in various ways
• can contain an prosthetic group (non protien) associated with the molecules
(more than one polypeptide coming together (secondary/ tertiary structure)
Tertiary polypeptide chains called domains/subints and interact
Different structures:
-globular
-fibrous
-membrane
Hydrophobic groups in middle are attracted to each-other. So it affects the pairing of polypeptides. Are also close together to maintain shape
Has hydrophilic part on the surface of protien making it soluble in cytoplasm
68
What are waxes?
Compromised of long chains of fatty acids attached by and ester bond to long chain of alchahol
-(simple lipids)
Are extremely hydrophobic
High melting temperature
Insoluble in water
(On bee wax/waex, spermaceti wax, carnatuba palm, waxy coating on plants)
69
What are the structural properties of waxes
-used for food storage (bees construct combs in winter)
- have water proofing (plants & animals)
-energy storage substance (plankton)’
-prevent excess water loss
-protection (parasite & insects)
[sperm whale is able to maintain buoyancy]
70
What are enzymes?
-globular protien
-act as catalysts
-reused repeatedly
-speed up reactions that already occur by lowering activation energy
71
What are catalysts?
They altar rate of chemical reaction without undergoing permanent change
72
What is the activation energy?
The minimum amount of energy needed to activate reaction
(Reactions need certain amount of energy to start)
73
Why do enzymes lower activation energy?
To lower (energy) for reaction needed to take place ( as they increase strain bonds in reactants ) . so increased reaction can take place whilst at lower temperatures than normal
-HENCS causes metabolic processes to increase, whilst human body maintains body temperature of 37 degrees (considers low for chemical reactions)
(Makes organisms more efficient for survival )
74
What is consisted in the enzyme structure?
Has specific 3D shape from primary protein structure
-active site: has small amount of amino acids (is smaller in larger enzymes)
-has substrate fit into active site to form enzyme-substrate complex.
Substrate held together by temporary specific amino acids in active site and substrates molecule groups
75
What is the induced fit model in an enzyme?
The proximity of substrate
(changes in enzyme environment) cause change in enzyme shape to form an function able active site.
[ enzymes mold around substrate]
As it changes shape, enzymes put strain on substrate molecule. This then distorts bonds in substrate, lowering activation energy needed to break bonds.
76
How do you measure the enzymes catalysed/ progress in an reaction?
From the formation of products in reaction
From the disappearance of substrate
77
What occurs when measuring the progress of an enzyme-catalysed reaction?[when measuring substrate and product conc.] (Explain graph trend about enzymes)
-lots of substrate, mean easy contact with empty active site. Without product in the way. So active site filled rapidly, breaking substrate into product
-more product is produced than substrate. So more difficult for substrate to contact in active site. As products in the way and less substrate . Slow rate of formation of product. Hence decrease substrate concentration and then flattens out on graph when all substrate used up
78
What is the correct term to describe the active site and substrate?
As
COMPLIMENTARY
79
What factors can affect enzyme reaction?
-temperature
-ph concentration
-enzyme concentration
-Substrate concentration
80
How does temperature affect enzymes?
Increases kinetic energy. So enzymes and substrate molecules closer to eachother in given time=more enzyme-substrate complex formed
-if temperature further rises, bonds will break down in enzyme. So substrate fit less into active site. So slower reaction
-then eventually will denature, making enzyme not function able
81
Why is it that enzymes optimum temperature in humans is 40C (3C higher than average )
• body intakes extra energy needed to maintain high body temperature (no need for higher temp.)
• some enzymes denature at high temperature
•high metabolic rate increase body temp. So higher energy (too high reaction could be damaging)
82
When will enzymes begin to deform in humans? (Temp.)
At 45C
83
When will enzymes begin to denature in humans (temp
60C
84
How can PH of a solution be calculated by?
-log[H+]
85
How does ph affect and enzyme?
-Increase or decrease from optimum reduces rate of enzyme reaction
-the Ph neutralizes the charges on amino acids within active site. So substrates can not attach to active site .so less binding
-(Breaks bonds in enzyme structure/specific 3D shape that create cross links , so changes active site shape) BREAK PEPTIDE BONDS and ionic bonds
-Causing substrate unable to attatch to active site. So can’t form enzyme-substrate complex
Too acidic Ph= causes lots of hydrogen ions (H+)
Too alkaline pH = cause lots of hydroxyl ions
(Which affects the bonding as it changes shape of active site)
86
Does it require lot of ph to denature enzyme?
No, only a little
87
How can the substrate concentration affect enzyme-substrate complex?
The reaction will increase directly proportionally to fixed concentration of enzyme as substrate concentration increases (will continue when enzyme in excess)
-low subtrate, enzymes have limited substrate to collide with
-will fill until rate of reactions is at maximum Velocity, (no longer affecting reaction)
(Can only be measured if all factors are at optimum)
88
How does the effect of enzyme concentration affect enzyme-substrate complex?
Reaction will increase proportionally to fixed concentration of substrate as enzyme increases
An Increase in enzyme will increase reaction. So more substrate bonded to active site. (There will be an immediate affect if the reaction lacks enzymes)
But when more enzymes than substrate, graph levels of. So not affecting rate of reaction
But if substrate in excess , there is optimum temperature, PH and no inhibitors . Then is rate of. Reaction is directly proportional through out
89
What are the nucleic acids?
•ribonucleic acid (RNA)
• deoxyribonucleic acid (DNA)
90
What is the nucleotide structure compromised of?
• monomer
•Pentose Sugar
• Phosphate group
• nitrogen containing organic base (cytosine, thymine, uracil, adenine, guanine)
Are formed together via condensation reaction to form mononucleotide
• require phosphates and nitrogen
91
What is a dinucleotide?
Formed by condensation reaction between two mono-nucleotide-
(Creates phosphodiester bond between deoxyribose sugar & phosphate group)
92
What is an polynucleotide?
Continued linkage if dinucleotide attached by phosphodiester binds
93
What is the structure & function of ribonucleic Acid?
• polynucleotide
• pentose sugar is ribose
• organic bases: adenine, cytosine, guanine, uracil
• transfers genetic information from DNA to ribosome
• RNA involved in protein synthesis
• polyppeptide or of nucleotide
•has three types of RNA:
-mRNA (messenger RNA) used in transcription
-tRNA (transfer RNA) used in translocation
rRNA (Ribosomal RNA)
94
What is the structure of deoxyribonucleic acid?
•pentose sugar: deoxyribose
• organic base: adenine, thymine, guanine, cytosine
• made of two polynucleotides joined together by hydrogen bonds between bases (A-T = 2H bonds, C-G = 3 H bonds
• antiparrallel
•complimentary base paring
• double helix
(dna polymerase enzyme join nucleotides to form the backbone)
95
What is the base pairing in an DNA structure?
Adenine—thymine ()
Guanine—cytosine
(Have hydrogen bonding, are complimentary)
[ quantities of bases in bonds same but ratio might vary]
96
What is the double helix structure in DNA ?
Polynucleotide chains twisted
-phosphate and deoxyribose wind round eachother forming double helix that are anti parallel
-(phosphate and deoxyribose form backbone of DNA molecule)
97
Why is the DNA molecule stable?
Phosphodiester backbone protects chemicals reactive bases inside double helix
Hydrogen bonds link base pairs bridges between phosphodiester uprights. (Cytosine and guanine have 3 bonds)
98
What is the function of DNA?
-hereditary material responsible for passing genetic information from cell to cell
-provide infinite variety of sequence bases along length of DNA molecule which provide genetic diversity in organism
Codes for protiens
-dna replication & protien synthesis
99
How many base pairs are there in mammalian cells?
3.2 billion bases
100
How does the DNA molecule support its function?
-has stable structure (passes from one generation to another without change)
-hydrogen bond means easy separation for DNA replication & protein synthesis
-VERY LARGE MOLECULE carries lot of genetic information as it is an large molecule
-genetic information protected by phosphodiester backbone from chemical & physical forces
-base paring allow dna replication and information transfers of mRNA
(Function dependant in base pairs possessed)
101
What is the collagen a form of? (Detailed)
Fibrous protien: that has a 3D & quaternary structure of protiens
Containing long polypeptide chains in an repeating sequence of amino acids
102
What is the structure of an collagen?
-fibrous protien=strength
-has non polar r group, so insoluble in water
-strands of polypeptide held by hydrogen bonds and cross links (between side chains of amino acids) to provide greater strength
-tertiary protein structure
Consist of 25% of human body
Covalent cross links-fibres-collagen fibre
103
What are the functions of collagen in areas of the body?
They can form tendons:
• fibres which are in parallel bundles that run along length of tendon, in direction of tendon
can form skin:
•fibrous form layer, with fibres running in different directions in different layers( connect muscle to bone for skeletal movement)
Provides strength to many parts of body
-used to make bone
-found in artery walls to prevent vessels bursting from high blood pressure
104
What are examples of other fibrous proteins?
-keratin: very hard & strong, used for fingernails, has high amounts of cystine, has sulfur, so makes disulphide bonds, so very strong
-elastin: can stretch and recoil. Elastin molecules are cross linked to each other (in lungs) (in bladder). Is found in blood vessels to maintain high blood pressure by stretching and recoiling
105
Why are there disputations between the lock & key model and induced fit model?
Lock and key model:
-used to provide simplest diagrammatic way to understand specificity if enzymes
-helps understand concept; enzymes (key) active site (lock) concept
Induced fit model:
-model is more likely to be correct as enzyme temporarily changes changes shape to accommodate substrate when binding (induced )
-it’s not a perfect fit
106
What is trypsin?
It is produced by pancreas, and then activated in the small intestine
It catalyses proteins digested into long amino acids
Has optimum temperature of 37 degrees
Has optimum PH range of 7 to 9
107
What is the turnover number?
The amount of time it takes to turn known concentration of substrate into products per minute
108
What enzymes has highest turnover number?
Catalase: it catalysed H202/ hydrogen peroxide which is poisonous
109
How can you increase the rate of reaction when measuring substrate concentration of fixed enzyme concentration? (Without changing substrate )
Increasing concentration of fixed enzyme
110
Was is (V max)
Maximum velocity
=
111
How do you calculate PH of solution?
• -log10[H+]
112
What is enzyme inhibitation
Chemicals that can slow down rate of enzyme catalysed reaction
-by directly/ indirectly intefering with functioning active site
- *important in controlling cell reaction to avoid build up of excess product*
113
What are the two types of inhibitors?
-Competitive
-non competitive
114
What are competitive Inhibitors?
Molecule shape is SIMILAR to substrate
Compete with substrate for active site occupation
(Increase substrate concentration, inhibitors affect is reduced)
(Greater concentration of inhibitors, longer substrate-enzyme complex takes place)
-they are not permanent bonded to active site
Slows down rate of reaction
115
What are non-competitive inhibitors?
-attach to enzyme at different binding sites. ( not the active site)
-has very different shape to substrate
-when binded, causes active site on enzyme to distort, so changes shape in a way substrates can no longer occupy it= so enzyme can’t function
-(an increase in substrate concentration does not decrease effect of inhibitors)
Slows down rate of reaction
116
What is end product/feedback inhibition?
End product acts as an inhibitor for one enzyme involved in earliest stage of metabolic pathway
(End product becomes non-competitive inhibitors)
More end product, so more inhibition, so less product produced (occurs when end product is in excess) opposite applies
117
What are the two ways of measuring the rate of enzyme catalysed reaction?
Measuring
-products formed per time unit
-substrates used up in given time
118
How do you measure the rates of product formed?
By recording the time of enzyme in different temperatures (plot on graph)
Then by calculating the rate of reaction
1
——-
Time (seconds)
119
What is the rate of reaction?
An proccesed result
120
How do you calculate the initial rate?
Calculating the gradient of the tangent at steepest part of each curve
Equation (x/y) in cm
121
How can you calculate the amount of substrate used up as a measure mod the rate of reaction?
By measuring the cross section area the enzyme has spread to from catalysing with substrate?
[cross section area=pi,r(sqaurwd)
Exp method:continuous sampling (constantly observing spread of enzymes)
122
What is the biuret test?
Test for protien
-add sample solution into test tube, and add equal volume of sodium hydroxide at room temp.
-add drops of dilute copper sulfate solution and mix gently
-if present then purple colour (portrays peptide bonds)
123
What is water?
It consists of two hydrogen atoms & one oxygen atom
-oxygen atom has slight delta negative charge, hydrogen atom has slight delta positive charge,
-have polar covalent bonds between positive and negative delta, which electrons are not shared equally
-is dipolar( helps create hydrogen bonds)
-inorganic molecules
-biological molecule
[formula H20]
124
What does dipolar mean?
Has both positive and negative charge
125
How are water molecules bonded together?
From positive pole (H) attracting to the negative pole (O) creating a hydrogen bond
[ which connects water moleculs together and are weak]
126
What are the properties of water and their biological importance?
-high specific heat capacity:
water requires large amount of energy to be separated from lots of cohesion. So has high boiling point. So provides stable environment for ectothermis& buffers them against sudden temperature change
-high latent heat of vaporisation:
hydrogen bond between water molecules cause lots of energy needed to evaporate water. So effective for cooling manmels & leaves down as water evaporates into water vapour
-Cohesion/adhesion:
helps form Collins of water which allows capillary action to take place in the xylem vessel during transpiration
-surface tension:
water moleculs which meet air, tend to pull back to body of water. Means water surface support small organisms, allowing them to use it as an habitat
-metabolism:
involved in hydrolyses/condensation reactions, reaction in aquatic environments, photosynthesis
-solvent for polar molecules/ions:
Water dissolves gasses, waste, inorganic ions, small hydrophilic molecules and enzymes. So allow these to be transported. This is due to dipoles attract to positive and negative charge of ions
-transparent
Allows light rays to pass through to aquatic plants so they can photosynthesise
-provides support as it is not easily compressed
-water density:
Ice floats on surface from hydrogen bonds between water molecule forming more dense solid. So ice platforms can be used for resting , and provides insulation for leaves underneath
-inorganic ions
127
Where can you find inorganic molecules?
-in solution of cytoplasm of cell
-body fluids
-part of large molecule
(In concentration ranging from high to low)
128
What are pyrimidines?
Thymine , cytosine
129
What are parines
Adenine, gaunine
130
What is the genetic code?
Order of bases on the template strand
131
What is a codon?
Triple base codes (code for amino acids)
132
What are degenerate codons?
Mutations
133
What were the reason for doubt that DNA was the genetic code?
Structure was not complex enough to assemble 20 amino acids from 4 bases
DNA could not leave the nucleas to go to cytoplasm
134
How ere the doubts that DNA was the genetic code disproved?
Discovers that they were base triplet code G4 codons 4(power of 3)= 64
-messenger RNA carry message code to ribosome from nucleas
135
Why can nucleic acids only be synthesized in 5-to 3 direction?
‘In vivo’ living organism…
Enzyme DNA polymerase only attach nucleotides to hydroxyl group on the 3 carbon molecule
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How was DNA semi-conservative replication proved?
By the meselsohn and Stalin experiment
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What are the stages in cell division?
Nuclear division: nucleas divided (mitosis, meiosis)
Cytokinesis: whole cell divides
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Why is DNa copied in DNA replication?
To enable all daughter cell to have genetic information to produce necessary protiens and enzymes
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What is required for semi-conservative replication to take place?
1) nucleotide with bases (adenine, thymine, guanine, cytosine) present
2) DNA strands act as templates to attach nucleotides
3) DNA Polymerase (enzyme)
4) source of chemical energy
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What is the process of DNA semi-conservative replication ?
-DNA helicase causes DNA strands to break hydrogen bonds connecting bases
-Double helix separates into two strands
-exposed polynucleotides strands act as template for complimentary free nucleotides to bind by specific base paring
-nucleotides join together in condensation reaction by DNA polymerase, forming phosphodiester bonds, to form missing polynucleotide strands on the two polynucleotide DNA strands
Results in each new dna molecule having an original DNA strand and an new DNA molecule
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What is ATP
Adenosine triphosphate
-phosphorylated macromolecule
(Universal currency of energy found in all organisms)
-had adenine: nitrogen containing organic base
-an activated nucleotide
-ribose: sugar molecule with 5 carbon ring structures , acts as backbone to parts
-phosphates: chain of 3 phosphate molecules
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How is energy released from ATP?
-bonds between phosphate group are unstable =low activation energy = bonds are easily broken
When broken releases large amount of energy
ATP + (H20)-> ADP + P + Energy
This reaction is catalysed by ATP hydrolase
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How is ATP formed to become an energy storage source?
(Synthesis)
-condensation reaction
-catalysed by enzyme ATP synthesis
(Reversible reaction of energy released
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What procces require synthesising ATP?
-during photosynthesis (photo phosphorylation)
-respiration: oxidative phosphorylation
-phosphate group transferred from donor molecule to ATP
(Substrate level phosphorylation)
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What are the comparisons between ATP and fats/ carbohydrates as an energy source
-ATP an immediate energy source of a cell due to the instability of the phosphate molecules
-glucose(glycogen) better long term energy store
• less energy from reaction is released. So it is in more manageable quantities than greater quantities from glucose that are less manageable from those release by glucose
• hydrolysis ATP to ADP is a single reaction whilst glucose breakdown is a longer reaction to release energy
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What are the uses of ATP?
-metabolic processes: used to build up macromolecules from basic units
- movement: provides energy for muscle contraction
(Shorten length of muscle fibres as muscle filament slide past each other, because of ATP)
-active transport: provides energy to change shape of carrier protein, allowing molecules to move against concentration gradient
-secretion: needed to form lysosomes necessary for secretion of cell products
-activation of molecule: inorganic phosphate used to phosphorylate compounds to make them more reactive… lowering activation energy in enzyme catalysed reaction
-co-transport
-nerve transmission
-mitosis/ meiosis
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What are the types of inorganic ions used for?
Hydrogen: affecting pH of solution = determining the function enzyme
Sodium : involved in co transport of glucose and amino acid across cell membrane
Phosphate: components of DNA so have structural role in DNA and energy storage in ATP
Iron: component of haemoglobin transport to oxygen
