Biological Molecules Flashcards

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1
Q

What do carbohydrates and lipids contain?

A

Carbon, hydrogen and oxygen

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2
Q

What are proteins made of?

A

Carbon, hydrogen, oxygen, nitrogen, sometimes sulphur

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3
Q

What are nucleic acids made of?

A

Carbon, hydrogen, oxygen, nitrogen and phosphorus

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4
Q

What are macromolecules?

A

Biological molecules that contain a very large number of atoms. Many of these are polymers

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5
Q

Monomer and polymer of carbohydrates?

A

Monomers: monosaccharides
Polymers:polysaccharides

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6
Q

Monomer and polymer of proteins?

A

Monomer: amino acids
Polymers: polypeptides

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7
Q

Monomer and polymer of nucleic acids?

A

Monomers: nucleotides
Polymer: polynucleotides

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8
Q

Monomer and polymer of lipids?

A

They are macromolecules not polymers.
Made of base units joined together in a non-repeating pattern
Glycerol +3 fatty acids= triglyceride

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9
Q

How are polymers formed from monomers?

A

By condensation reactions, molecule of water formed in process, grouped hydroxyl and hydrogen

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10
Q

What is hydrolysis?

A

Breaking polymer into individual monomers, require water to break bond

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11
Q

Condensation vs hydrolysis?

A

Condensation: monomers joined together, forms water, forms bonds
Hydrolysis: monomers broken apart, requires water, breaks bonds

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12
Q

What are proteins?

A

Chains of amino acids that form a polypeptide
They contain carbon, hydrogen, oxygen, nitrogen and sometimes sulphur
They are in enzymes, muscles, blood, hair, skin, bone

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13
Q

Examples of proteins?

A

Amylase, hormones, collagen, melanin

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14
Q

What is a dimer?

A

Two monomers bound together

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15
Q

What is a polymer?

A

3 or more monomers bound together

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16
Q

What happens when peptide bonds
Form between amino acids toform a dipeptide?

A

1.) amino acids join in a condensation reaction
2) hydrogen bonds together
3.) a water molecule is left

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17
Q

What are globular proteins?

A

Soluble and spherical shape, soluble due to presence of charged r groupwater molecules can surround the protein

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18
Q

What are fibrous proteins?

A

Straight chain polypeptides,side by side held in place by hydrogen bonding, insoluble, lots of disulphide bridges so they are more resistant to physical and chemical attack

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19
Q

What are primary protein structures?

A

Sequence chains of amino acids

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20
Q

What is a secondary protein structure?

A

Hydrogen bonding of of the peptide backbone, causes amino acid to fold in repeating pattern

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21
Q

What is a tertiary protein structure?

A

Three-dimensional folding pattern of a protein due to side chain interactions

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22
Q

What is a quaternary protein structure?

A

Protein consisting of more than one amino acid chain

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23
Q

What is glucoses structure?

A

6 carrion atoms, sugars with 6 carbon atoms, heroes sugars, its a single sugar molecule

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24
Q

What are key properties of monosaccharides?

A

Soluble in water
Hydrophilic
Can be joined chemically to form larger carbs

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25
Q

What’s the difference between alpha and beta glucose?

A

Betas OH is above the ring and alphas is below

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26
Q

How do you break a glycosidic bond?

A

Add water to break bond, converts it back to original monosaccharides (hydrolysis)

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27
Q

How do you make Sucrose?

A

Glucose + fructose

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28
Q

How do you make lactose?

A

Glucose and galactose

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29
Q

What is amylose structure?

A

Unbranched alpha glucose in a larger number in a helix shape with hydrogen bonds between glucose molecules

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30
Q

Structure of amylopectin?

A

Branched chains every 25-30 glucose molecules of alpha glucose , joined by glycosidic bonds

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31
Q

Structure of glycogen?

A

Very compact polymer of alpha glucose which is branched

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32
Q

Why do enzymes convert glycogen back to glucose so quickly?

A

High volumes of free ends

33
Q

Structure of cellulose?

A

Polymer of beta glucose
Every 2nd beta glucose molecule flips
Unbranched polysaccharide
Straight chains

34
Q

What’s the function of cellulose?

A

Hydrogen bonds form between chains making them very strong (microfibrils) which can join together to make cellulose fibre (cell wall), important for stopping cell wall bursting

35
Q

What can lipids be used for?

A

Waterproofing, major structure of membrane, energy source

36
Q

what are triglycerides made up of?

A

A glycerol and 3 fatty acids

37
Q

What are phospholipids made of?

A

Phosphate + glycerol + 2 fatty acids

38
Q

What do phospholipids form?

A

Bilayers (membrane)

39
Q

What happens when lipase breaks the ester bond due to hydrolysis?

A

Glycerol and fatty acid molecules are released

40
Q

Points of the induced fit model?

A

Enzymes catalyse reaction by lowering activation energy
Bind to a substrate to form enzyme substrate complex
Shape of active site isn’t exactly complimentary to the substrate so slightly changes

41
Q

How does temperature denaturing occur?

A

Tertiary structure is held by weak bonds, if enough weak bonds are broken by heating the tertiary structure unravels this causes active sites shape to be lost and the enzyme denatures

42
Q

What are 2 conditions that denature an enzyme?

A

Too high temperature
Too low/high pH

43
Q

What is the test for starch?

A

Add iodine
Orange to blue/black is a positive test

44
Q

Test for reducing sugars?

A

Benedict’s reagent and het
Blue to green, yellow,orange or brick red is positive

45
Q

Test for non-reducing sugars?

A

Following negative Benedict’s test add acid and boil (hydrolysis), cool the solution and add an alkali to neutralise, add Benedict’s reagent and heat, positive test- blue to green,yellow,orange brick red

46
Q

Test for proteins?

A

Add burnet
Blue to purple- positive

47
Q

Test for lipids?

A

Dissolve lipid in ethanol, add distilled water, positive = white emulsion forms

48
Q

Examples of reducing sugars and what they can do to copper sulphate?

A

Glucose, fructose, galactose, lactose, maltose
Copper sulphate (blue) is reduced in Benedict’s reagent to copper oxide (brick red)

49
Q

Example of non-reducing sugar and what it does to copper sulphate?

A

Sucrose
Can’t reduce copper sulphate as the reducing group is used up by the glycosidic bond
Hydrolyse sucrose (boil in acid then add an alkali to neutralise, this breaks the glycosidic bond and then add Benedict’s so it turns brick red

50
Q

How are polysaccharides formed?

A

When more than two monosaccharides join together by condensation reaction

51
Q

What is starch?

A

Mixture of 2 polysaccharides of alpha glucose, amylose + amylopectin

52
Q

What is DNA?

A

Store of generic information

53
Q

What is RNA (ribonuclease acid) role?

A

Transfers genetic information from DNA to ribosomes (protein factories), read the RNA and make polypeptides in translation

54
Q

What is a nucleotide made of?

A

Penrose sugar (sugar with 5 atoms)
Nitrogen-containing organic base
Phosphate group

55
Q

What is the Penrose sugar in a DNA nucleotide called?

A

Deoxyribose

56
Q

What are the 4 possible bases for nucleotides?

A

Adenine (A), thymine (T), cytosine (C), guanine (G)

57
Q

What does an RNA nucleotide consist of?

A

Phosphate group and one of four different bases

58
Q

What replaces thymine as a base in RNA?

A

Uracil

59
Q

What is a monomer?

A

Smaller units which are the components of larger molecules

60
Q

What are disaccharides?

A

Two monosaccharides joined together in a condensation reaction

61
Q

Features of glycogen that makes it useful?

A

Larger number of side branches (energy can be released quickly), relatively large but compact, maximising the amount of energy it can store,
Insoluble so it doesn’t effect water potential of cells

62
Q

Test for reducing and non reducing sugars?

A

Reducing: add the food sample in a liquid form
Add 2cm of Benedict’s reagent
Heat the mixture in a water bath for 5 mins, if solution turns brick red, orange/brown then reducing sugar is present
NON REDUCING: if solution is still blue add dilute hydrochloride acid so It can hydrolyse
Add sodium hydrogencarbonate to neutralise test
Ph paper used to check
Now add 2cm of Benedict’s reagent to solution and place in water bath
If non reducing sugar is present brick red will be observed

63
Q

Where are saturated lipids found?

A

Animal fats, don’t contain any carboncarbon double bond

64
Q

Where are unsaturated lipids found?

A

In plants, they contain carboncarbon double bond

65
Q

Triglycerides structure related to their properties?

A

High ratio of energy storing carbon-hydrogen bonds to carbon so they are excellent energy store
Low mass to energy ratio, less mass to move around
Release water when they are oxidised so good for organisms in dry environments

66
Q

How to do the emulsion test for proteins?

A

1.)Take a grease free test tube and add 2cm of sample and 5cm of ethanol
2.) shake the test tube to dissolve all lipids
3.) add 5cm of water and shake
4.) cloudy-white colour indicated the presence of a lipid
5.) as control, repeat experiment using water as the sample

67
Q

Features of disulphide bridges?

A

Interactions between soulful in r group of amino acid cysteine,
STRONG AND NOT EASILY BROKEN

68
Q

Features of Ionic bonds?

A

Form between the carbonyl and amino groups not involved in peptide bond, EASILY BROKEN BY PH AND ARE WEAKER THAN DISULFIDE BRIDGES

69
Q

Features of hydrogen bonds?

A

Numerous and easily broke

70
Q

How to carry out burnet test for proteins?

A

1.)Place sample in test tube with equal volume of sodium hydroxide at room temp
2.) add very dilute copper sulphate solution and mix
3.) a purple colour indicates presence of protein, negative would remain blue

71
Q

How does temperature affect the rate of enzyme-controlled reaction?

A

Rate of reaction increases up to optimum, kinetic energy increases, above optimum rate of reaction decreases as enzymes denature

72
Q

How does PH affect the rate of enzyme-controlled reactions?

A

Affects enzymes shape so disrupts the bond in tertiary structure

73
Q

How does enzyme concentration affect the rate of enzyme controlled reactions?

A

As enzyme concentration increases rate of reaction increases, more active sites for substrates to bind to, beyond a certain point there is no change, there are more active sites than substrates so concentration becomes limiting factor

74
Q

How does substrate concentration affect the rate of enzyme controlled reactions?

A

Rate of reaction increases as more enzyme-substrate complexes are formed, beyond a certain point the rate of reaction no longer increases as enzyme concentration becomes the limiting factor

75
Q

How does concentration of competitive reversible inhibitors?

A

As competitive reversible inhibitors increases, rate of reaction decreases as the active site are temporarily blocked by inhibitors so substrates cannot bind to them

76
Q

How does the concentration of non-competitive reversible inhibitors?

A

As concentration on non-competitive reversible inhibitors increases, rate of reaction decreases as the shape of enzyme is altered by the inhibitors

77
Q

Different between DNA and RNA chains?

A

DNA is a double helix of 2 polynucleotides joined by hydrogen where as RNA is a relatively short polynucleotide chain

78
Q

What are the 3 steps of semi-conservative replication of DNA?

A

1.) enzyme, DNA helicase, causing the two strands of DNA to separate breaking the hydrogen bonds between the complementary bases
2.) one of the strands is used as the template and complementary base pairing occurs between the templates strand and free nucleotides
3.) once activated nucleotides are bound the enzyme DNA polymerase joins them together by forming phosphodiester bonds, 2 identical strands of DNA formed.