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BIOLOGICAL MOLECULES Flashcards

TOPIC 1 (80 cards)

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1
Q

MONOMERS

A

smaller units from which larger molecules are made

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2
Q

POLYMERS

A

Molecules made from large number of monomers joined together

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3
Q

CARBONHYDRATES

A

Monosaccharide
Polysaccharide
Carbon, hydrogen, oxygen

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4
Q

PROTEINS

A

monomer-Amino acid
polymer-Polypeptide
compounds-Carbon, hydrogen, oxygen, nitrogen, and sulphur

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5
Q

NUCLEIC ACID

A

monomer-Nucleotide
polymer-Polynucleotide
compounds-Carbon, hydrogen, oxygen, nitrogen, and phosphorus

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6
Q

WHY ARENT LIPIDS POLYMERS

A

macromolecules but are not polymers- because they are not made of repeating set of monomers, but number of molecules joined together in non-repeating pattern

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7
Q

CONDENSATION REACTION

A

remove a molecule of water from two monomers, forming chemical bond between them

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8
Q

HYDROLSIS REACTION

A

reaction that breaks a chemical bond
Between two molecules-Involves use of water molecule

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9
Q

GLYCOSIDIC BOND

A

C–O–C link
Between two sugar molecules
Formed by condensation reaction it is covalent bond

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10
Q

MONOSACHARIDES

A

monomers, single sugar units

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11
Q

DISACCHARIDES

A

two monosaccharides joined together condensation reaction forms glycosidic bond
eg. maltose, sucrose,lactose

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12
Q

POLYSACHARIDES

A

polymer, lots of repeating units of monosaccharides condensation reaction forms glycosidic bond
eg.cellulose,starch,glycogen

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13
Q

GLUCOSE NOT ABLE TO BE STORED

A

cannot be stored within cells as it is soluble, it would dissolve in cytoplasm of cells, lowering its water potential, causing water to flow in cell, resulting in it bursting

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14
Q

STARCH + GLYCOGEN STORAGE

A

glucose in plants as starch and glycogen stores glucose in animal cells as glycogen- store excess glucose until organism requires energy from respiration

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15
Q

GLYCOGEN + STARCH STRUCTURE

A

polymer of a-glucose
insoluble-dont affect water potential
large-cant cross cell membrane
compact-store lots in cell
branched-provides lots of ends easily hydrolysed to release glucose used in respiration

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16
Q

AMYLOSE

A

Polysaccharide in starch
Made of α-glucose
Joined by 1,4-glycosidic bonds
Coils to form a helix

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17
Q

AMYLOPECTIN

A

Polysaccharide in starch
Made of α-glucose
Joined by 1,4 and 1,6-glycosidic bonds
Branched structure

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18
Q

CELLULOSE

A

straight chained polymer of β-glucose
very strong and rigid molecule which provided structural support in plant cell walls, preventing it from bursting when cell is filled w/water
Straight chains of cellulose interact w/each other w/hydrogen bonds forms structures known as microfibrils
microfibrils provide strength to cellulose structure

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19
Q

FIBRILS

A

Long, straight chains of β-glucose glucose
Held together by many hydrogen bonds

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20
Q

TESTING FOR CARBOHYDRATES-REDUCING SUGARS

A

1.Add excess Benedict’s to test solution
2.Boil mixture
3.If reducing sugar is present solution will change from blue to green/yellow/orange/brick-red

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21
Q

TESTING FOR CARBOHYDRATES-NON REDUCING SUGARS

A

1.Add Benedict’s reagent and heat, if it remains blue do following steps
2.Add hydrochloric acid and heat
3.Neutralise acid w/sodium hydroxide
4.Add Benedict’s reagent and boil
5.If solution now turns red then non-reducing sugar was initially present

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22
Q

WORKING OUT UNKNOWN CONCENTRATION

A

1.Create set of known concentrations of sugar solutions
2.Carry out Benedict’s test on each
3.Place solutions into colorimeter and measure absorbance OR filter precipitate, dry it and weigh mass
4.Plot these results onto a graph
5.Draw line of best fit
6.Carry out the benedict’s test on your unknown solution and measure its absorbance/mass of precipitate
7.Take absorbance/mass value of your unknown, read from line using graph to determine concentration

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23
Q

TESTING FOR STARCH

A

iodine dissolved incKI reacts with starch
colour change from orange to black

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24
Q

TRIGLYCERIDES

A

Formed by the condensation of one molecule of glycerol and three molecules of fatty acids
Forming 3 ester bonds

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25
HOW DOES THE STRUCTURE OF TRIGLYCERIDES RELATE TO ITS FUNCTION
Large ratio of energy-storing carbon-hydrogen bonds compared to number of carbon Atoms; lot of energy is stored in molecule high ratio of hydrogen to oxygen atoms they Act as metabolic water source Do not affect water potentials and osmosis Have relatively low mass
26
PHOSPHOLIPIDS
Formed by the condensation of one molecule of glycerol and two molecules of fatty acid Held by two ester bonds Phosphate group is attached to glycerol
27
HOW DOES THE STRUCTURE OF PHOSPHOLIPIDS RELATE TO ITS FUNCTION
have two charged regions, so they are polar In water, they are positioned so that heads are exposed to water and tails are not This forms phospholipid bilayer which makes up plasma membrane around cells
28
SATURATED FATTY ACIDS VS UNSATURATED FATTY ACIDS
carbon-carbon single bonds vs carbon-carbon double bond
29
PHOSPHOLIPDIS VS TRIGLYCERIDES
.both have C,O,H .both contain glycerol .both contain ester bonds .fatty acids can be saturated or unsaturated .two fatty acid chains + phosphate group vs triglycerides' three fatty acid chains .hydrophilic region as well as hydrophobic region vs entirely hydrophobic .form micelles or bilayers when in solution vs don't form micelles
30
TEST FOR LIPIDS
1.mix sample w/ethanol 2.add water 3.milk white emulsion will appear if result is positive
31
AMINO ACIDS
monomer that form protein polymers are 20 naturally occurring amino acids have an -NH2 and -COOH but have variable region which differs between each amino acid – this referred to as R group
32
PEPTIDE BONDS
Covalent bond joining amino acids together in proteins C–N link between two amino acid molecules Formed by condensation reaction
33
POLYPEPTIDE
polymer made up of many amino acid monomers joined together by peptide bonds
34
PROTEIN STRUCTURE
1. P-sequence of amino acids on polypeptide chain 2. S- folding or coiling create β pleated sheet or an α helix held in place by hydrogen bonds 3. T-further folding- create unique 3D shape held in place by hydrogen, ionic and disulphide bonds 4. Q-More than one polypeptide chain in protein
35
GLOBULAR PROTEIN
soluble proteins w/biochemical functions such as enzymes and hormones
36
FIBROUS PROTEIN
insoluble and have structural functions e.g. keratin in nails and hair
37
TEST FOR PROTEINS
Biuret solution is used to test for presence of a protein-added to sample and if solution changes from blue to lilac/purple then protein is present
38
ENZYMES
tertiary structured proteins speed up rate of reaction – w/X getting used up themselves specific to one type of reaction due to their specific tertiary shape Enzymes bind to substrates-substrates bind to specifically shaped part of enzyme known as active site- active site is complementary to substrate Once substrate has bound to enzyme an enzyme-substate complex is formed
39
HOW ENZYMES LOWER THE ACTIVATION ENERGY
1.Bending bonds in substrate, putting strain on bonds, and making them more likely to break 2.Bringing two molecules close together, overcoming natural repulsion between two molecules, making bond between two molecules more likely
40
INDUCED FIT MODEL
enzyme active site is not initially complementary to substrate active site moulds around substrate-puts tension on bonds -lowers activation energy
41
LOCK + KEY MODEL
active site of an enzyme is structured to fit specifically shaped substrate Once substrate binds to active site, enzyme will facilitate reaction and release products of reaction
42
EXPLAIN HOW ACTIVE SITE AN ENZYME CAUSES HIGH RATE OF REACTION (3)
.lowers activation energy .induced fit causes active site to change shape .enzyme-substrate compels cases bonds to form
43
HOW TEMPERATURE AFFECTS ENZYME ACTIVITY
At low temperatures, there is not enough kinetic energy for successful collisions between enzyme and substrate At too high temperature, enzymes denature, active site changes shape and enzyme- substrate complexes cannot form
44
HOW PH AFFECTS ENZYME ACTIVITY
Too high or too low a pH will interfere w/ charges in amino acids in active site breaks ionic and hydrogen bonds holding tertiary structure in place- active site changes shape and enzyme denatures Different enzymes have different optimal pH
45
HOW SUBSTRATE CONCENTRATION AFFECTS ENZYME ACTIVITY
At low substrate concentrations, there will be fewer collisions between the enzyme and substrate At high substrate concentrations, rate plateaus because all enzyme active sites are saturated
46
HOW ENZYME CONCENTRATION AFFECTS ENZYME ACTIVITY
At low enzyme concentrations, there will be fewer collisions between the enzyme and substrate At high enzyme concentrations, rate plateaus because there are more enzymes than substrate, so many empty active sites
47
COMPETITIVE INHIBITOR
molecule that is same/similar shape as substrate-binds to active site Prevents enzyme-substrate complexes from forming + reduces rate of reaction
48
NON-COMPETITIVE INHIBITOR
molecule that binds to an enzyme at allosteric site Causing active site to change shape Preventing enzyme-substrate complexes from forming
49
RP1: INVESTIGATING INTO EFFECT OF VARIABLE ON RATE OF ENZYME CONTROLLED REACTION
.Add 5cm3 of distilled water to 2cm potato cylinder-Crush to form smooth paste using pestle and mortar .Label each of your test tubes w/dilution starting from 0.5M – 2.5M .Starting w/2.5M tube, using syringe add 10cm3 of 2.5M H2O2 -Use stock solution and distilled water to make up other concentrations and add to appropriate labelled test tube .Using forceps, dip filter paper disc into potato paste and tap off excess .Starting w/2.5M solution, drop filter paper disc into hydrogen peroxide solution and measure time, to nearest second, that it takes from striking surface to sink, to float up surface again .You will need to have your stopwatch ready as you drop disc in .Make note of time .Remove disc from the tube using forceps and discard it on your paper towel .Repeat steps 3-5 for each solution
50
RP1: WHY SHOULD PASTE BE SMOOTH
Lumps would affect surface area and rate of enzyme-controlled reaction
51
RP1: WHY DID DISC RISE
Oxygen formed from breakdown of hydrogen peroxide would form on surface of paper disc-would become less dense causing it to rise
52
RP1: HOW WOULD YOU CALCULATE RATE FROM AN END POINT REACTION
1/Time taken
53
RP1: WHY SHOULD SMALLER INTERVALS BE USED
obtain more accurate optimum
54
RP1: WHY COMPLETE REPEATS
more reliable mean and allow identification of anomalies
55
RP1: WHY IS BUFFER SOLUTION USED
keep PH constant see whether change in PH will affect enzyme controlled reaction
56
RP1: WHY WOULD A COLOUR STANDARD BE USED
rate is calculated by time of indicator to change colour
57
RP1: WHY ARE TEST TUBES KEFT IN WATER BATH BEFORE ADDING ENZYME TO SUBSTRATE
equilibrate reach temperature of water bath
58
RP1: SUGGEST IMPROVEMENTS
use buffer solution to prevent changes in pH, use thermostatically controlled water bath
59
HOW TO WORK OUT CONCENTRATION OF NEWLY MADE SOLUTION OR SPECIFIC CONCENTRATION
C1=V1 C2=V2 C1=concentration of original stock solution V1=volume of original solution to use C2=concentration of new solution V2=total volume of new concentration
60
PHOSPHDIESTER BOND
Condensation reactions join phosphate of one nucleotide to pentose sugar of another nucleotide
61
DNA STRUCTURE RELATED TO ITS FUNCTION
sugar - phosphate backbone-gives strength compact shape sequence of bases-allows information to be stored long molecule- stores large amount of information information can be replicated-complementary base pairing double helix- molecule stable prevents code being corrupted chains held together by weak hydrogen bonds chains can split for transcription
62
PROTEIN SYNTHESIS
contains genes which codes for order of amino acids in protein
63
RNA
single, relatively short, polynucleotide chain-used in production of proteins
64
MRNA
A single stranded straight chained molecule, made of bases which are read in triplets called codons carry genetic code out of nucleus to ribosome for formation of 1 polypeptide
65
TRNA
single strand of RNA folded in many places forming complementary base pairs- shape is described as clover leaf It has an amino acid binding site and triplet of bases called an anticodon carry specific amino acids to mRNA at ribosomes for formation of polypeptide
66
RRNA
rRNA is found in cytoplasm Along w/protein molecule, it forms ribosomes
66
DNA VS RNA
.Two strands vs One strand .Very long vs Relatively short .Adenine, thymine, guanine, and cytosine vs Adenine, uracil, guanine, and cytosine .Stores genetic information vs Transfers genetic information in formation of proteins and helps form ribosomes
67
DESCRIBE STRUCTURE OF DNA
1. Polymer of nucleotides 2. Each nucleotide formed from deoxyribose, phosphate group and nitrogenous base 3. Phosphodiester bonds between nucleotides 4. Double helix held by hydrogen bonds 5. Hydrogen bonds between adenine, thymine and cytosine, guanine
68
SEMI-CONSERVATIVE REPLICATION
DNA replication is semi- conservative replication each new molecule of DNA contains one original strand and one new strand
69
DNA HELICASE
unwinds DNA and breaks hydrogen bonds between bases- allows nucleotides to attach to each strand and for each strand to act as template
70
DNA POLYMERASE
joins adjacent DNA nucleotides together- catalyse forming phosphodiester bonds in sugar-phosphate backbone catalyses condensation reaction
70
ATP
nitrogen containing base – Adenine, pentose sugar – ribose and 3 phosphate groups
71
STAGES OF DNA REPLICATION
1. DNA helicase separates DNA strands by breaking hydrogen bonds 2. Each strand acts as template 3. Free nucleotides attach to exposed bases by complementary base pairing 4. adenine w/thymine and guanine w/ cytosine 5. DNA polymerase joins nucleotides forming phosphodiester bond
71
MESELSON + STAHL EXPERIMENT
grew E Coli bacteria in broth containing Nitrogen- originally contained heavy isotope of Nitrogen (15N)- E Coli incorporated 15N into any newly made nucleotides After while they transferred sample of E Coli from 15N broth into broth containing lighter isotope (14N) of Nitrogen – now any time E Coli made new nucleotides they would incorporate 14N making this DNA less dense DNA containing 15N
71
MESELSON + STAHL RESULTS
results proved that replication was semiconservative- first generation of DNA molecules contained both heavy and light DNA so ruled out conservative replication second generative of DNA contained intermediate molecules and molecules which only contained light DNA, this ruled out dispersive, proving that semi-conservative was correct mode of DNA replication Later generations have thicker bands of ‘light only DNA’ -shows there are more molecules of 14N only DNA with each generation
72
FUNCTION OF ATP
.storage and transfer of energy within cells- activation of enzymes and contraction of muscles .releases energy in small amounts .cannot leave cells through cell membrane .involved in biosynthesis of macromolecules
73
ATP HYDROLASE
Enzyme that catalyses the hydrolysis of ATP into ADP +Pi
74
ATP SYTHASE
Enzyme that catalyses the synthesis of ATP from ADP + Pi
75
PROPERTIES OF WATER
.metabolite- condensation reaction .solvent so metabolic reactions can occur .high heat capacity-buffer changes in temperature .large latent heat of vaporisation-provides a cooling effect .cohesion-produces surface tension supporting organisms .cohesion-supports column of water
76
INORGANIC IONS
Sodium- used in co-transport of glucose and amino acids in small intestine Hydrogen-Changes pH of solutions by making it more acidic + create electrochemical gradients in production of ATP Iron-component of haemoglobin in red blood cells oxygen ions transport around body Phosphate-Important in production of ATP and nucleic acids

A-level Biology (8 decks)

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