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OCR A Biology A-Level > 2.3 Biological Molecules (Spec) > Flashcards

2.3 Biological Molecules (Spec) Flashcards

(47 cards)

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1
Q

Biochemical molecules

A 
Carbon
Nitrogen
Hydrogen
Oxygen
Sulfur
Sodium 
Potassium
Iron
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2
Q

Ca2+ function

A

Nerve impulse transmission, muscle contraction

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3
Q

Glycosidic bond formation/breakage

A

Monosaccharide -> Disaccharide/Polysaccharide
Condensation reaction
Polysaccharide/Disaccharide -> Monosaccharide
Hydrolysis reaction

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4
Q

Hydrogen bond formation (Water)

A

Affinity to shared pair of electrons in covalent bond
Oxygen > Hydrogen
Partial positive on oxygen, partial negative on hydrogen
Electrostatic attraction between lone pair on O and partial positive on H of different molecules

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5
Q

High boiling point function in water

A

Coolant - Narrow temperature range of enzyme activity

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6
Q

Density function

Ice < Water

A

Insulating layer for lakes/ponds

Creation of semi-aquatic habitat

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7
Q

Na+ function

A

Nerve impulse transmission, kidney function

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8
Q

K+ function

A

Nerve impulse transmission, stomatal opening

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9
Q

H+ function

A

Catalysis, pH determination

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10
Q

NH4+ function

A

Bacterial NO3- production

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11
Q

NO3- function

A

Plant amino acid & protein formation (N)

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12
Q

HCO3- function

A

Blood pH maintenance

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13
Q

Cl- function

A

Cell pH maintenance (Na+/K+)

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14
Q

(PO4)3- function

A

Bone, cell membrane, nucleic acid & ATP formation

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15
Q

OH- function

A

Catalysis, pH determination

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16
Q

Cohesion function in water

A

Transport medium

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17
Q

Adhesion function in water

A

Capillary action

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18
Q

Polarity function in water

A

Universal solvent

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19
Q

Starch structure & function

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A

20-30% amylose
70-80% amylopectin
Dense energy storage
Water-insoluble

20
Q

Amylose structure

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A

Alpha-glucose polymer
1-4 glycosidic bonds
Straight chain -> helical structure

21
Q

Amylopectin structure

Study These Flashcards
A

Alpha-glucose polymer
1-4 & 1-6 glycosidic bonds
Highly branched structure
Dense energy storage

22
Q

Glycogen (properties, structure, function)

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A 
Water-insoluble
Alpha-glucose polymer
1-4 & 1-6 glycosidic bonds
Highly branched structure
Dense energy storage - animals' high metabolic demand
23
Q

Cellulose

Study These Flashcards
A

Water-insoluble
Beta-glucose polymer
Alternate monomers rotated 180 degrees
1-4 glycosidic bonds form on opposite chain sides
High compressive strength
Hydrogen bonds - chains, microfibril, macrofibril

24
Q

Benedict’s test

Study These Flashcards
A 
For reducing sugars
Equal volume of solution and sample
Heat in water bath
CuSO4 & NaOH solution
Blue - Negative test
Green - Low reducing sugar conc
Yellow/Orange - Medium reducing sugar conc
Red - High reducing sugar conc
25
Iodine test
For starch Equal volume of solution and sample Negative test - orange Positive test - blue-black
26
Reagent test strips
Colour-coded chart - reducing sugar conc | Industrially manufactured
27
Triglyceride structure/formation
``` 3 fatty acid chains Glycerol backbone Ester bonds between fatty acid chain & backbone Ester bond formed in condensation Ester bond broken in hydrolysis ```
28
Triglyceride function
Long-term energy storage Thermal insulation -> reduce heat loss Cushioning protection of vital organs Aquatic animals' buoyancy
29
Phospholipid structure, function, properties
Hydrophilic phosphate head (Inorganic phosphate group) Hydrophobic fatty acid tails (hydrocarbon chain ending in methyl group) Phospholipid bilayer - plasma membrane Ester bond between glycerol & fatty acid chain, glycerol & phosphate head
30
Cholesterol function
Stability to cell membrane | Regulates membrane fluidity
31
Emulsion test
``` For lipids Equal volume of ethanol, sample & distilled water Shaken, not stirred Milky emulsion - positive test Clear solution - negative test ```
32
Amino acid structure
Amine group, R-group, carboxyl group
33
Dipeptide/Polypeptide formation/breakdown
Peptide bond (C-N) forms in condensation reaction Hydroxyl of carboxyl on one amino acid Hydrogen of amine of another amino acid Catalysed by peptidyl transferase - present in ribosomes Hydrolysis reverse reaction Catalysed by protease enzymes
34
Primary protein structure
Peptide bonds | Order of amino acids
35
Secondary protein structure
Hydrogen bonds within polypeptide chain | Alpha helix/Beta pleated sheet dependent on primary structure
36
Tertiary protein structure
``` Ionic bonds Hydrogen bonds Disulfide bridges Hydrophobic/Hydrophilic interactions Within polypeptide chain, between R-groups ```
37
Quaternary protein structure
``` Ionic bonds Hydrogen bonds Disulfide bridges Hydrophobic/Hydrophilic interactions Between subunits/polypeptide chains ```
38
Biuret test
``` For proteins Equal volume of solution and sample CuSO4 & KOH solution Blue solution - negative test Lilac solution - positive test ```
39
Nucleotide structure
``` Pentose sugar Phosphate group Nitrogenous base DNA - Deoxyribose, phosphate & A, T, C or G RNA - Ribose, phosphate & A, U, C or G ```
40
Polynucleotide formation
Phosphodiester bond formed between 3' hydroxyl and 5' phosphate of adjacent nucleotides Catalysed by DNA/RNA polymerase Formed in condensation reaction/broken by hydrolysis
41
DNA structure
Sugar phosphate backbone (Deoxyribose and phosphate) Phosphodiester bonds between 3' hydroxyl and 5' phosphate Nitrogenous bases attached to C1 of deoxyribose Hydrogen bonds between complementary nitrogenous base pairs Pyrimidines always pair with purines (A-T and C-G)
42
DNA purification
Grind cells in pestle and mortar - break cell walls (plant-cellulose, bacterial-peptidoglycan, etc) Add detergent - break membranes, release cell contents into solution Add salt - breaks hydrogen bonds -> DNA & water Add protease-break down histones associated w/ DNA Add ethanol down test tube side to prevent agitation and allow DNA to precipitate
43
DNA replication
1. DNA helicase breaks hydrogen bonds between bases, unwinds & unzips the DNA double helix 2. Free DNA nucleotides arrange by complementary base pairing and form hydrogen bonds with exposed bases of existing strands 3. DNA polymerase catalyses formation of phosphodiester bonds between free DNA nucleotides in condensation (3' hydroxyl/5' phosphate) Each daughter DNA molecule has one old strand and one new strand
44
Genetic code nature
Non-overlapping: Each codon is read individually Triplet code: Three-base sequence codes for one amino acid Universal: Same codons code for same amino acids in all organisms Degenerate: >1 codon codes for each amino acid
45
DNA transcription (protein synthesis)
DNA helicase breaks hydrogen bonds between bases in DNA at locus of gene coding for desired protein Free RNA nucleotides arrange by complementary base pairing to exposed template strand (complementary-template, identical-coding), form hydrogen bonds w/ template strand RNA polymerase catalyses phosphodiester bond formation between RNA nucleotides Pre-mRNA matures as introns removed by enzyme (introns: non-coding) mRNA leaves nucleus by nuclear pore
46
DNA translation (protein synthesis)
mRNA moves to ribosome mRNA passes between ribosomal subunits tRNA molecules w/ complementary anticodons to mRNA codons enter ribosome and form hydrogen bonds 2 tRNA molecules can enter ribosome at any time tRNA carries specific amino acid, peptide bond formed between amino acids, catalysed by peptidyl transferase tRNA w/ complementary anticodons continue to bring amino acids to ribosome until stop codon reached - no amino acid on stop codon - polypeptide released.
47
ATP structure
Nucleotide derivative: Ribose, adenine and phosphate groups AMP: Adenosine monophosphate (1 phosphate) ADP: Adenosine diphosphate (2 phosphates) ATP: Adenosine triphosphate (3 phosphates) Most energy stored in final phosphate bond in chain Inorganic phosphates added in condensation/removed in hydrolysis

OCR A Biology A-Level (31 decks)

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