2.1.2 Biological Molecules Flashcards
1
Q
What is the general formula for carbohydrates?
A
Cx(H2O)y
2
Q
What is a monosaccharide?
A
Single unit of sugar/ carb
3
Q
What is a disaccharide?
A
Two units of sugar/ carb
4
Q
What is a polysaccharide?
A
2+ units of sugar/ carb
5
Q
What is the molecular formula for glucose?
A
C6 H12 06
6
Q
What is a hexose monosaccharide?
A
A single carb unit made of 6 carbons
7
Q
How are carbons numbered in a hexose/ pentose ring?
A
Clockwise from the Oxygen atom
8
Q
What’s the difference between an Alpha and Beta glucose?
A
Position of 0H- group on C1; alpha down; beta up
9
Q
What are 2 properties of glucose?
A
- Polar
2. Soluble in water (OH-)
10
Q
Why does glucose need to be soluble?
A
Dissolve in cytosol of a cell
11
Q
How is a gylcosidic bond formed?
A
Condensation reaction between two OH- groups of two glucose molecules, producing H2O
12
Q
How are glycosidic bonds broken?
A
Hydrolysis reaction between two glucose molecules, using H2O and enzymes
13
Q
Why are glycosidic bonds broken?
A
To release glucose from energy store
14
Q
What is a pentose monosaccharide?
A
A single unit of sugar/ carb made of 5 carbons
15
Q
What are two examples of pentose monosaccharides?
A
- Ribose (RNA)
2. Deoxyribose (DNA)
16
Q
What two polysaccharides is Starch made up of?
A
- Amylose
2. Amylopectin
17
Q
What bonds are in Amylose?
A
1-4 Glycosidic bonds between alpha
18
Q
What bonds are in Amylopectin?
A
1-6 Glycosidic bonds 1:25 subunits and 1-4
19
Q
Properties of Amylose? (3)
A
- Helix
- Compact
- Less soluble than glucose
20
Q
Properties of Amylopectin? (2)
A
- Branched
2. More soluble than Amylose
21
Q
Why is it useful that energy storage molecules (e.g starch) are branched? (2)
A
- Compact- store more at once
2. Stable- doesn’t react so easily, retain more glucose
22
Q
What bonds are in Cellulose?
A
1-4 glycosidic bonds between beta glucose, every other beta upside down
23
Q
What is the structure of Cellulose?
A
Straight chain
24
Q
Why is Cellulose used for cell walls? (2)
A
- Forms microfibrils (H bonding) -> macrofibrils -> fibres
2. Fibres are strong and insoluble
25
What shape do 1-4 glycosidic bonds make?
Straight
26
What shape do 1-6 glycosidic bonds make?
Branched
27
Lipids are ____molecules made up of ____
Macromolecules; monomers
28
What does a triglyceride contain?
One glycerol molecule and 3 fatty acids
29
How are triglycerides formed?
Esterification; OH- from both molecules react and produce 3 molecules of water
30
What bonds are in triglycerides?
Ester
31
What kind of a reaction is esterification?
Condensation
32
How are triglycerides broken down?
Hydrolysis; water is added and enzyme Lipase (bc Trigl. are lipids)
33
What is a saturated fatty acid chain?
No double bonds
34
What is an unsaturated fatty acid chain?
C=C present
35
What is a monosaturated fatty acid chain?
One C=C present
36
What is a polysaturated fatty acid chain?
More than one C=C present
37
How do C=C affect triglycerides?
Make a kink in the chain, less compact, lower melting point
38
What is a phospholipid?
A triglyceride containing a phosphorus group instead of a 3rd fatty acid chain
39
Is the glycerol molecule still present in a phospholipid?
Yes
40
Which parts of a phospholipid are polar/ hydrophilic?
Phosphate group
41
Which parts of a phospholipid are non- polar/ hydrophobic?
Fatty acid tails
42
What are phospholipids useful for due to their hydrophobic/ hydrophilic nature?
Surface active agents
43
What are cell membranes made out of?
A phospholipid bilayer
44
What group is cholesterol in?
Sterols
45
What is cholesterol used for?
Stability and fluidity in cell membranes
46
Where is cholesterol in the cell membrane?
The hydrophilic OH- lines up with the hydrophilic phosphate heads of the phospholipids, the hydrophobic carbon rings are in between the hydrophobic fatty acid tails of the bilayer
47
What is the structure of Cholesterol?
Hydrophobic carbon rings and a hydrophilic OH- group of the first carbon ring
48
What are peptides made up of?
Amino acid monomers
49
What is a protein?
One or more polypeptides arranged as complex macromolecules
50
What is the structure of an amino acid?
Central carbon, amine group, carboxyl group and R- group
51
How do amino acids join?
The OH- group in the carboxyl reacts with the amine forming a peptide bond; a molecule of water is released; catalysed by enzyme
52
How are peptide bonds broken?
Protease enzyme catalyses hydrolysis reaction; water is used; amine and carboylic acid group reformed
53
What is a polypeptide?
Many amino acids joined
54
What is a dipeptide?
Two amino acids joined
55
What is the primary structure of proteins?
Amino acid sequence (peptide bonds) directed by info in the DNA
56
What is the secondary structure of proteins?
Alpha helix or beta pleated sheet is made by hydrogen bonds between amino acids (not R- group)
57
What is the tertiary structure of proteins?
Folding into final 3D shape and R- group interactions
58
What R- group interactions take place in the tertiary structure of proteins?
1. Hydrophobic interactions- phobic inside of protein, philic outside (soluble)
2. Hydrogen bonds
3. Ionic bonds
4. Disulfide bridges
59
Which amino acid can form disulfide bridges?
Cystine
60
What is the quaternary structure of proteins?
Joining of two or more individual proteins (subunits)
61
What elements are present in carbohydrates?
C, H, O
62
What elements are present in lipids?
C, H, O
63
What elements are present in proteins?
C, H, O, N, S
64
What elements are present in nucleic acids?
C, H, O, N, P
65
What are the 3 properties of water?
1. Polar
2. Hydrogen bonding
3. High Specific latent heat
66
Why is water polar?
2 lone pair of electrons repel = delta negative oxygen and delta positive H = trigonal planar
67
Why can water hydrogen bond?
Delta negative oxygen attracted to delta positive hydrogens of other water molecules
68
Why does water have a high specific latent heat?
Overcome H bonds
69
What are the 5 functions of water?
1. Solvent
2. Medium for chemical reactions
3. Transport medium
4. Coolant
5. Habitat
70
Why is water a solvent?
Polarity
71
Why is water a medium for chemical reactions?
Allows chemicals close proximity to react; high specific heat capacity and pH 7
72
Why is water a transport medium?
H bonding; capillary action
73
Why is water a coolant?
Prevents big temp changes; high specific heat latency
74
Why is water a habitat?
1. Stable
2. Ice less dense, insulating
3. Surface tension, insects
75
How do you test for starch? Positive result?
Iodine solution
| Brown --> Blue- black
76
How do you test for reducing sugars? Positive result? (name 3)
1. Benedict's solution
2. Reagent strips
3. Colorimetry
77
How do you test for non- reducing sugars? Positive result?
Boil in HCl -> Benedict's solution
Clear blue --> Cloudy brick-red precipitate
Green, yellow, red increasing conc.
78
How do you test for lipids? Positive result?
Emulsion test
| White emulsion layer
79
How do you test for proteins? Positive result?
Biuret's solution
| Blue --> Purple
80
Benedict's solution procedure?
Mix sample with it, heat in water bath
81
Reagent strips procedure?
Dip stick into sample, remove, wait for results
82
Colorimetry procedure?
1. Calibrate colorimeter using cuvette of distilled water
2. Use a range of known conc. of glucose to produce calibration curve
3. Compare unknown sample to curve
83
How does colorimetry test for reducing sugars?
Measures absorbance of light through liquid
| More conc = less light passes through (% transmission)
84
In colorimetry, what is transmission?
The light that passes through the sample
85
What is a biosenser?
Device that detects the presence/ conc. of a biological substance in a solution
86
What is the biosenser mechanism?
Analyte present -> Change in transducer -> Signal produced
87
How are retention values (Rf) calculated?
Distance moved by solute / distance moved by the solvent
88
In thin paper chromatography, what is the solute?
Substance that travels on the paper by the solvent
89
In thin paper chromatography, what is the solvent?
Liquid that travels up through the paper
90
What are the 3 types of protein?
1. Globular
2. Conjugated globular
3. Fibrous
91
Structure/ properties of Globular proteins? (3)
1. Compact, spherical
2. Tertiary structure- hydrophilic R- groups outside = soluble
3. Quaternary structure- mult. polypept.
92
Structure/ properties of Fibrous proteins?
1. Long, thin, rope-like
2 Insoluble- hydrophobic R-groups
3. Strong
4. Quatnerary structure- mult. polypept.
93
What is a conjugated protein?
Globular protein containing a prosthetic group
94
What is a prosthetic group? Examples?
Globular protein containing a non- polypeptide component
| e.g. metal ions, vitamins
95
Insulin: type of protein, structure/ properties, function?
- Globular
- Soluble
- Hormone
96
Haemoglobin: type of protein, structure/ properties, function?
- Conjugated globular
- 4 polypeptides: 2 alpha, 2 beta- opposite to each other
- Haem group in each chain
- Soluble
- Carries oxygen (Cu2+)
97
Why are globular proteins soluble?
Hydrophilic R- groups on outside
98
Catalase: type of protein, structure/ properties, function?
- Conjugated globular
- 4 Haem groups
- Enzyme for hydrogen peroxide
99
Keratin: type of protein, structure/ properties, function?
- Fibrous
- Cysteine- disulfide bridges = strong, inflexible and insoluble
- Structural protein, e.g. skin, hair, nails
100
Elastin: type of protein, structure/ properties, function?
- Fibrous
- Long, flexible
- Flexibility to structures, e.g. alveoli
101
Collagen: type of protein, structure/ properties, function?
- Fibrous
- 3 polypeptides wound together like rop = flexible
- Strong bonds
- Connective tissue, e.g. skin, tendons, ligaments
