Biochemistry Flashcards

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1
Q

Water structure

A

Polar molecule
Form hydrogen bonds
Solid less dense than liquid
Tetrahedral arrangement

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2
Q

Water properties

A

Cohesive moves as a mass due to h bonding
Adhesive water molecules attracted to other materials

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3
Q

Water uses

A

Acts as a solvent due to its polarity helping transport in and out cells
Efficient transport medium cohesion and adhesion in capillary action
Coolant
Stable doesn’t change temp easily ice floats forming insulating layer for organisms under to survive
High surface tension for pond skaters

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4
Q

Carbohydrate structure

A

Contain carbon hydrogen and oxygen
Also known as saccharides or sugars

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5
Q

Glucose

A

Hexose monosaccharide
Polar
Highly soluble in water due to hydrogen bonds forming
2 forms beta and alpha

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6
Q

Alpha glucose

A

Carbon 1 OH is below

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7
Q

Beta glucose

A

OH is above carbon 1

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8
Q

Condensation reactions

A

2 alpha glucose molecules react
Hydroxyl groups interact forming water
Glycosidic bond is formed
Disaccharide forms - maltose

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9
Q

Sucrose

A

Fructose and glucose

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10
Q

Lactose

A

Galactose and glucose

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11
Q

Starch

A

Glucose is stored as starch after photosynthesis
Polysaccharide

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12
Q

Amylose

A

joined together by 1/4 glycosidic bonds
Forms a helix which is stabilised by h bonds less soluble and good for storage

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13
Q

Amylopectin

A

1/4 glycosidic bonds and 1/6 glycosidic bonds branches structure every 25 glucose subunits

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14
Q

Glycogen

A

Energy storage in animals and fungi
More branches mor compact many free ends to quickly remove or add glucose

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15
Q

Cellulose

A

Beta glucose 1 upside dow forms 1-4 glycosidic bond
Straight chain molecule
H bonds with other strands forming microfibrils which form macrofibrils makes cell walls
Important in diet forms fibre difficult to break down

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16
Q

Lipids

A

Know as fast and oils
Contain carbon hydrogen and oxygen
Fats solid at rtp oils liquid at rtp
Non polar molecules

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17
Q

Macromolecules

A

Large complex molecules that aren’t built from repeating monomers

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18
Q

Triglycerides

A

One glycerol (alcohol) and 3 fatty acids (carb acid)
Interact forming ester bonds
Esterification = condensation polymerisation
Store energy / insulation

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19
Q

Saturated fats

A

No double bonds present
Solid at rtp

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20
Q

Unsaturated fats

A

Fatty acid w double bonds
Causes molecule to kink and bend so can’t pack closely therefore liquid at rtp
Plants contain these
Healthier?

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21
Q

Phospholipids

A

Contain phosphate ions which are soluble in water
2 fatty acid hydrophobic tails
Surfactant - form thin layer on surface fatty tails sticking up
Key in cell membranes

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22
Q

Sterols

A

Complex alcohol molecules based on 4 carbon ring with oh one end which is polar hydrophilic
Cholesterol - keep fluidity of membrane and used in manufacturing steroid hormones and vitamin d etc

23
Q

Roles of lipids

A

Formation of hydrophobic barriers
Hormone production
Electrical insulation
Waterproofing
Long term energy storage providing thermal insulation buoyancy and cushioning of organs

24
Q

Amino acids

A

All have same basic structure
Varying R groups
20 AA commonly found
Require 9 essential

25
Q

Synthesis of peptides

A

Carboxylic acid and amine form a peptide bond and water
Catalysed by enzyme peptidyl transferase in ribosomes
Different R groups interact forming different bonds which form different shapes

26
Q

Primary structure

A

Only involves peptide bonds

27
Q

Secondary structure

A

Atoms of aa structure interact forming H bonds
Pulls into coil shape - alpha helix
Can form sheet like structures forming beta pleated sheet
Result of H bonding

28
Q

Tertiary

A

Folding or coiling of protein brings R groups closer so interact
Hydrophobic/Philic attractions
H bonds
Ionic bonds
Disulphide bonds between sulphur atoms

29
Q

Quaternary structure

A

Two or more subunits (polypeptide chains)
Same as tertiary interactions
Eg Hb

30
Q

Types of proteins

A

Globular
Conjugated
Fibrous

31
Q

Globular proteins

A

Compact, water soluble, roughly spherical hydrophobic on inside
Insulin - hormone transported in blood stream so need to be soluble

32
Q

Conjugated proteins

A

Globular proteins that contain a prosthetic group
Eg haemoglobin is a conjugated globular protein because it is soluble and contains Fe2+
Catalase enzyme which contains 4 haem groups to interact w H2O2

33
Q

Fibrous proteins

A

Long insoluble molecules due to high proportion of hydrophobic r groups
Repetitive AA
Eg Keratin large No of sulphur r groups form disulphide bridges
Elastin quaternary protein stretchy fibrous molecules
Collagen -3 polypeptide chains wound together like rope

34
Q

Reducing sugar test

A

Grind sample and put in test tube
Add equal vol of Benedict’s
Heat mixture in water bath
If sugar present reduces Cu2+ to Cu3+ turns to brick red

35
Q

Non reducing test

A

First boil with HCl and then same test as reducing sugars

36
Q

Test for starch

A

Add iodine if turn blue/black starch is present in the sample

37
Q

Test for lipids

A

Emulsion test
Mix with ethanol and shake if white emulsion present lipid present

38
Q

Nucleotides

A

Contain Penrose monosaccharide phosphate group and a nitrogenous base
Phosphate group bonds w oh group of Pentose sugar carbon 3- phosphodiester bond

39
Q

Dna

A

Pentose sugar is deoxyribose one fewer oxygen than ribose
Each nucleotide has 1/4 different bases

40
Q

Pyrimidines

A

Single carbon ring
Cytosine Thymine
CaT Egyptian pyrimidines

41
Q

Purines

A

Double carbon ring
Adenine and guanine
Pure-ine Ag- pure silver

42
Q

Dna helix

A

Double strand held together by hydrogen bonding
Run in opposite directions
Allows dna to be copied and transcribed

43
Q

Base pairing rules

A

Adenine and Thymine form 2 hydrogen bonds
Cytosine and guanine form 3 hydrogen bonds

44
Q

RNA

A

Transfer genetic info from dna
mRNA is shorter so can leave nucleus
Ribose sugar
Thymine replaced by uracil

45
Q

Semi conservative replication

A

DNA helix unwound and separate into 2 strands
Free DnA nucleotide pair w comp base join up w phosphodiester bonds

46
Q

DNA helicase

A

Unwinds and separates strands
Catalyses breaking of hydrogen bonds

47
Q

Dna polymerase

A

Catalyses formation of phosphodiester bonds between free nucleotides
Can only bind to C3 3->5 replication

48
Q

Continuous/discontinuous replication

A

Strand is unzipped from 3 end and continuously replicated as unzipping occurs
Other strand is unzipped from the 5 end so dna polymerase has to fully wait until finished- dna produced in fragments (Okazaki fragments) - discontinuous replication

49
Q

Start and stop codons

A

Triplet base sequence which starts coding of a specific protein so sequence isn’t read from base 2 for example
Non overlapping code

50
Q

Degenerate code

A

Lot more codons than AA
AA can be coded for by many different codons

51
Q

Transcription

A

DNA is unzipped DNA helicase
Sense strand (coding strand) codes for protein from 5’ to 3’
Antisense strand acts as template rna comp base sequence as sense strand
Phosphodiester bonds / RNA polymerase forming mRNA
Leaves via nuclear pore to ribosome

52
Q

Translation

A

mRNA binds to specific site on ribosome holds mRNA in position while decoded
tRNA carries anticodon which comp pairs with mRNA also carries a specific amino acid which is joined together in correct sequence peptide bond forms
Repeat until reach a stop codon

53
Q

Test for proteins

A

Biuret test
Purple positive result