3 - Biological Molecules Flashcards

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1
Q

What is a polar molecule? Give an example.

A

A molecule with a slight positive charge at one end (𝛿+) and a slight negative at the other (𝛿-). eg. water

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2
Q

What bond is formed between 2 monosaccharides in a condensation reaction?

A

glycosidic

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3
Q

Name the bond holding amino acid monomers together

A

peptide

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4
Q

What reaction breaks polysaccharides into their constituent parts? (What are the additional reactants/products)

A

Hydrolysis reaction

you must add water

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5
Q

Give 3 examples of globular proteins

A
  • enzymes
  • antibodies
  • hormones
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6
Q

Water is a solvent. How does water affect reactions?

A

increases the rate of reaction (more particles to collide with and change direction)

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7
Q

Glucose, fructose and galactose are all what type of sugars?

A

Hexose monosaccharides

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8
Q

Water helps control the temperature in our cells. What 2 properties help it do this?

A

High specific heat capacity (a buffer for temperature change)
High latent heat of vaporisation (cooling effect through evaporation)

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9
Q

α-glucose + α-glucose –>

A

maltose

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10
Q

Are polar molecules hydrophilic or hydrophobic? How can we tell?

A

Hydrophilic, they dissolve in water

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11
Q

What is the molecular formula of galactose?

A

C₆H₁₂O₆

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12
Q

What happens to polar molecules in water? Why is this important?

A
  • All polar molecules dissolve in water

- Water can therefore be used as a solvent to transport polar molecules in and out of cells

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13
Q

Describe the structure of amylopectin

A
  • polymer of glucose (1,4 glycosidic bonds)

- branched (1,6) glycosidic bonds

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14
Q

A chain of β-glucose molecules makes what?

A

cellulose

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15
Q

A chain of α-glucose molecules makes what?

A

starch

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16
Q

What are the 2 types of starch?

A

Amylopectin and amylose

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17
Q

Disaccharides are made through what type of chemical reaction? (what additional products/reactants are needed?)

A

condensation (also makes water)

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18
Q

What type of protein (shape) is insulin? Why does it do this and what bonds are formed?

A
  • globular
  • hydrophobic components protected from aqueous environments of the blood or the cell
  • hydrophilic and hydrophobic interactions
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19
Q

Define isomer

A

compounds with the same moleclar formulae but different arrangements (structural formulae) and therefore different properties

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20
Q

Which type of starch hydrolyses more quickly? Why?

A

Amylopectin

-branched, therefore, more accessible bonds to hydrolysed at one time

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21
Q

Describe the structure of amylose

A
  • polymer of glucose
  • helical
  • unbranched
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22
Q

Water’s polarity means it has _____ properties

A

cohesive

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23
Q

glucose + fructose –>

A

sucrose

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24
Q

glucose + galactose –>

A

lactose

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25
Q

Describe the structure of an amino acid

A
  • Central carbon atom
  • H atom
  • Amine group (NH3)
  • Carboxylic acid functional group (COOH)
  • R group
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26
Q

What are the 4 types of bonds between proteins monomers? (tertiary structure)

A
  • hydrogen
  • ionic
  • disulfide bridges
  • hydrophillic and hydrophobic interactions
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27
Q

What type of sugar is maltose and how is it made (reactants and type of reaction)?

A

disaccharide
α-glucose + α-glucose
condensation reaction

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28
Q

What makes a protein have a quarternary structure?

A

2 or more seperate polypeptide chains

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29
Q

What elements do nucleic acids contain?

A

CHONP

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30
Q

What elements do carbohydrates contain?

A

CHO

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31
Q

What elements do proteins contain?

A

CHONS

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32
Q

What elements do lipids contain?

A

CHO

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33
Q

What is the structure of a triglyceride?

A

Glycerol backbone with 3 fatty acid groups coming off

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34
Q

Suggest why a specific fatty acid may be liquid at room temperature.

A

It is unsaturated (C=C) casuing kinks, unable to pack as tightly together

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35
Q

What is a fatty acid?

A

Long polymers of carbon and hydrogen

with a carboxyl group at the end (-COOH)

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36
Q

What bond is present between each glycerol and fatty acid in a triglyceride?

A

An ester bond

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37
Q

How many ester bonds are present in a triglyceride

A

3

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38
Q

Lipids are short-term/long-term energy stores

A

Lipids are long-term energy stores

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39
Q

What is the structure of a phospholipid?

A

Phosphate ion with 2 fatty acid branches

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40
Q

Which enzyme catalyses the addition of amino acids in the ribosomes?

A

Peptidyl transferase

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41
Q

What are the 2 types of secondary protein structure?

A

alpha helix or a beta pleasted sheet

42
Q

What bonds determine the secondary protein structure?

A

Hydrogen

43
Q

What is a conjugated protein?

A

a protein that contains a non-protein component or a prothestic group (eg. haem in haemoglobin)

44
Q

State the properties of collagen

A

strong
flexible
inelastic

45
Q

State the properties of keratin

A

inelastic
insoluble
fibrous
strong

46
Q

Describe the quarternary structure of collagen

A

3 polypeptide chains twisted and held together by cross-linkages

47
Q

Why is collagen inelastic

A

Cross-linkages

stabilised by twisted polypeptide chains

48
Q

What 5 things should you mention when you compare proteins

A
SPADES
S-shape
P-purpose (funtional/structural)
A-acid sequence (repetitive/irregular)
D-durability (to pH and temp)
E-examples
S-solubility
49
Q

Compare the acid sequence in globular and fibrous proteins

A

globular=irregular

fibrous=repetitive

50
Q

Compare the durability (pH and temp) in globular and fibrous proteins

A

globular=more sensitive

fibrous=less sensitive

51
Q

Compare the functionality in globular and fibrous proteins

A

globular=functional

fibrous=structral

52
Q

What is the name of the test for reducing sugars?

A

Benedicts test

53
Q

What does a positive test for reducing sugar look like?

A
Coloured precipitate will form
Blue=none
Green/yellow
orange/red
brick red=large amounts
54
Q

Is Benedicts test quanitative?

A

Semi-quanititative and subjective

55
Q

How does Benedicts test for reducing sugars work?

A

Reagent blue from Cu2+ ions
Reducing sugars are able to donate electrons
coloured precipitate formed
more sugar more Cu2+ ions reduced

56
Q

Which sugars are reducing sugars

A
All monosaccharides
Some disaccharides (maltose and lactose)
57
Q

How do you test for non-reducing sugars?

A

if reducing sugar test does not work
boil sugar solution with dilute HCl (this hydrolyses into monosaccharides)
neutralise with sodium hydrocarbonate
repeat benedicts

58
Q

What is the test for starch?

A

Iodine, goes from yellow to blue/black

59
Q

What is the structure of a nucleotide?

A

Pentose sugar (deoxyribose or ribose)
1’ - nitrogenous base
3’ - OH
4’ to 5’ to phosphate group (PO4 3-)

oxygen at top

60
Q

How do nucleotides join together

A

Condensation reaction OH on one joins with phosphate group on the next

61
Q

What are the 4 bases in DNA

A

Adenine
Thyamine
Guanine
Cytosine

62
Q

What are the 4 bases in RNA

A

Adenine
Uracil
Guanine
Cytosine

63
Q

What is the difference between a pyramidine and a purine?

A
Pyramidine = single ring
purine = dounle ring
64
Q

Which nucleotides are pyramidines?

A

C and T and U

65
Q

Which nucleotides are purine?

A

A and G

66
Q

How many hydrogens bonds can T and A bases form between each other?

A

2

67
Q

How many hydrogens bonds can C and G bases form between each other?

A

3

68
Q

State 3 differences between DNA and RNA

A
  • DNA has thyamine RNA has uracil
  • DNA deoxyribose, RNA ribose
  • DNA double stranded, RNA single stranded
69
Q

What is the sense strand?

A

Strand of protein used to code for proteins, 5’ to 3’

70
Q

What is the Anti-sense strand?

A

Template for mRNA, 3’ to 5’

71
Q

What is the backbone of DNA made of

A

Alternating phosphate sugar backbone

72
Q

What bond is formed between 2 nucleotide bases in a polynucleotide?

A

Phosphodiester bond

73
Q

What reaction adds a nucleotide base of to DNA?

A

condensation

74
Q

What is important about the backbone of DNA?

A

shields base pairs and protects them from damage

75
Q

Define triplet code

A

3 bases (1 codon) code for an amino acid

76
Q

Define degenerate

A

Different codons can code for the same amino acid

77
Q

What can mutations result in, in regard to proteins

A
  • protein not functional
  • protein not as effective
  • no protein is made
78
Q

Where does Transcription occur?

A

nucleus

79
Q

Where does translation occur?

A

ribosomes

80
Q

What is transcription?

A

The formation of a complementary molecule of mRNA from the DNA template (anti-sense strand)

81
Q

What enzymes catalase transcription

A

DNA helicase- unzips

DNA polymerase- joins to make one backbone from free nucleotides

82
Q

What is an exon

A

A region fo DNA that codes for proteins

83
Q

What is an intron

A

A region of DNA that does not code for proteins

84
Q

How does transcription work?

A

DNA unzips, free nucleotides pair up with anti-sense strand and form mRNA, leaves through nuclear pores

85
Q

What has to happen to the mRNA before it leaves the nucleus

A

introns removed by enzymes

86
Q

What is tRNA

A

transfer RNA

a single-stranded ribonucleotide chain folded into a cloverleaf shape, carries a specific amino acid

87
Q

What happens in translation?

A
  • mRNA enters ribosome
  • tRNA molecule with complementary bases joins mRNA
  • next tRNA molecule joins next codon
  • bonds form between amino acids they carry
  • first tRNA released and next one joins
  • repeated until stop codon
88
Q

Name the long term store fo energy for plants

A

starch

89
Q

Name the long term store fo energy for animals

A

glycogen

90
Q

What is the structure of an ATP molecule

A

Ribose (pentose sugar) bonded to
1’—3x phosphate groups
5’—adenine (base)

91
Q

What does ATP stand for?

A

Adenosine triphosphate

92
Q

ATP + H2O–>

A

ADP +Pᵢ (inorganic phosphate) +energy

93
Q

What enzyme catalyses the breakdown of ATP

A

ATP hydrolase (ATPase)

94
Q

Can ATP be stored?

A

No

95
Q

What feature of ATP makes it an efficient source of energy

A

It releases small and discrete quantities of energy

96
Q

Name 5 uses of ATP

A
synthesis of macromolecules
movement
active transport
secretion
Activiation of molecules
97
Q

Suggest, with reasons, why water is such an important component of the blood (5 marks)

A
  • polar solvent - can transport things as:
  • many biological molecules are polar
  • and ions are charged
  • liquid so transport medium
  • coolant to resistant to temp change
98
Q

Describe why water is such an important component of stroma in the chloroplasts and the matrix in the mitochondria. (5 marks)

A

(these are places where chemical reactions take place)

  • liquid
  • therefore allows movement of enzymes and substrates
  • that need to move in order for the reaction to occur
  • polar solvent
  • substrate, enzyme, products are polar
99
Q

What makes fats solid at r.t and oils liquid at r.t.

A

oils- unsaturated fatty acids
kinks therefore can’t pack tightly together
fats - saturated fatty acids

100
Q

Describe the formation of an ester bond in triglycerides

A

hydroxyl group from glycerol and hydroxyl group from fatty acid (actually -cooh) in condensation reaction

101
Q

describe how the emulsion test for lipids works

A

dissolve lipids in ethanol
mix water in
water is more soluble in ethanol than lipids so it displaces the lipids
lipids are not soluble in water so forms a suspension