Biological molecules Flashcards
1
Q
Bases in DNA
A
Cytosine
Guanine
Thymine
Adenine
2
Q
Bases in RNA
A
Cytosine
Guanine
Uracil
Adenine
3
Q
What are pyrimidines?
A
Smaller
1 carbon ring
C and T/U
4
Q
What are purines
A
Larger
2 carbon ring
G and A
5
Q
Describe a nucleic acid
A
A large polymer
6
Q
Describe a nucleotide
A
A monomer
7
Q
Differences between DNA and RNA
A
DNA-
Long double strand (helix)
Deoxyribose sugar
A, C, G & T
RNA-
Single short strand
Ribose sugar
A, C, G & U
8
Q
Similarities of DNA and RNA
A
Pentose sugars
Polymers
Made of nucleotides (monomers)
9
Q
What are the complementary base pairings?
A
A and T/U = 2 hydrogen bonds
C and G = 3 hydrogen bonds
10
Q
What bond is present in DNA?
A
Phosphodiester bond
11
Q
What carbon do the phosphate groups attach?
A
Number 5
12
Q
Covalent bond
A
Two atoms share a pair of electrons
13
Q
What bond forms between glucose molecules
A
Glycosidic bond
14
Q
What makes maltose
A
2 Glucose alpha
1,4
15
Q
What makes lactose
A
Glucose beta and galactose
1,4
16
Q
What makes sucrose
A
Glucose alpha and fructose
1,5
17
Q
Another name for glucose molecules
A
Monosaccharide
18
Q
Another name for maltose/sucrose etc. Molecules
A
Disaccharides
19
Q
What makes cellulose
A
2x alpha beta
1,4
20
Q
Properties of water
A
Temp constant- coolant (hydrogen bonds) Transport medium Minerals soluble in water Transparent to light Cohesion Polar
21
Q
What makes up amylose
A
Alpha glucose
(1,4)
(Helical)
22
Q
What makes up amylopectin
A
Alpha glucose
(1,4) and (1,6)
(Branched)
23
Q
What makes up glycogen
A
Alpha glucose
(1,4) and (1,6) every 25
(Branched and helical)
24
Q
Another name for glycogen/amylose/amylopectin/cellulose
A
Polysaccharides
25
Bond in lipids?
Ester bond
26
What is a triglyceride molecule made up of?
A glycerol molecule
| 3 fatty acids
27
What is a phospholipid made up of
Phosphate Group
Glycerol
Fatty acids
28
What is the reaction forming lipids called
Esterification
29
Test for lipids
Emulsion test
| Add ethanol- white emulsion forms
30
What are polysaccharides
Polymers made of monosaccharides
31
Joining together of lots of glucose molecules creates what?
A store of energy
32
What are characteristics of glycogen
1-4 and 1-6 carbon bonds
Chain formation with branches
Less tendency to coil
Easier to remove monomer units as has more ends
33
Why are polysaccharides good energy stores?
Compact
| Less soluble than monosaccharides
34
Why is it important that polysaccharides are less soluble in water
If they dissolved it would disrupt the cells water potential
35
Why are polysaccharides less soluble
Because of their size (larger)
36
Through what reaction are glycosidic bonds formed
Condensation
37
When bonded together what form does cellulose take
Straight chain
38
What prevents spiralling in cellulose
The alternate invention of the beta glucose molecules
39
What bonds prevent spiralling
Hydrogen bonds between rotated beta glucose molecules
40
What are micro fibrils made up of
Beta glucose molecules
41
What are macro fibrils made of
Microfibrils
42
Why is cellulose hard to digest
The glycosidic bonds are hard to break
43
Define lipids
A group of substances that are soluble in alcohol rather than water
44
Define macromolecule
Large biological molecule
45
Define phospholipid
A molecule consisting of glycerol, two fatty acids and a phosphate group
46
Characteristics of a lipid
Contain large amount of carbon and hydrogen and a small amount of oxygen
Insoluble in water
Soluble in alcohol
47
what do fatty acids contain
A carboxyl group at one end
| Hydrocarbon tail
48
Why are fatty acids, acids?
The carboxyl group can ionise hydrogen therefore it is an acid and can produce free H+ ions
49
What does the carbon bond in an unsaturated fatty acid inhibit
Hydrogen atoms can't bond to the molecule
50
What do double bonds do
Provide a kink making the molecule more fluid
51
When does an ester bond appear
During the condensation reaction the water is given off creating a covalent bond between the glycerol and fatty acids
52
Five functions of lipids
```
Energy source
Energy store
Insulation
Buoyancy
Protection
```
53
What is different in the structure of a phospholipid to a triglyceride?
One of the fatty acids is replaced with a phosphate group
54
What part of a phospholipid is hydrophillic
Head
55
Why are fatty acids hydrophobic
They are non polar
56
What describes the properties of phospholipids in water
Amphiphatic
57
In a phospholipid bilayer where are the heads and tails
Tails in heads out
58
Cholesterol is what
A steroid alcohol or sterol
| A type of lipid made without fattyacids or glycerol
59
Where is cholesterol found
Within the phospholipid bilayer
60
Define amino acids
Monomers of all proteins
61
Define peptide bond
A covalent bond formed when two amino acids are joined by a condensation reaction
62
What are proteins
Large polymers consisting of long chains of amino acids
63
Three functions of proteins
Form structural components
Tendency to adopt specific shapes and make into enzymes
Act as carriers in membrane
64
Structure of an amino acid
Amino group at one end
R group and an added hydrogen in the middle
Carboxyl group on the end
65
What enzyme breaks down peptide bonds
Protease
66
When two amino acids bond what is it called
Dipeptide
67
When a long chain of amino acids join together what is it called
Polypeptide
68
What is used to test for starch
Iodine
69
What colour change happens if starch present
Blue/black
70
What is used to test for reducing sugars
Benedicts reagent
71
Colour change if reducing sugars present
Red
72
Define a reducing sugar
Sugar which gives electrons to other molecules
73
What test for non reducing sugars
Benedicts solution
74
Colour change for non reducing sugars (low to high)
```
Blue
Green
Yellow
Orange
Red
```
75
Test for proteins
Biurent reagent
| Light blue to lilac
76
What are glycosidic bonds
Formed between monosaccharides by a hydrolysis reaction
77
Characteristics of monosaccharides
Soluble in water
78
Quaternary structure
Protein consists of more than one polypeptide chain
79
Secondary structure
Coiling or folding of an amino acids chain
80
Main forms of secondary structure
Helix and beta pleated sheet
81
Tertiary structure
3D shape of a protein molecule
82
If a protein adopts a supercoiled shape what is this called
Fibrous protein
83
If a protein adopts a spherical shape what is this called
Globular protein
84
Where are disulphide links
Between the R groups
85
What is a fibrous protein
Thin long structure
| Insoluble in water
86
What is a globular protein
Molecules with spherical shape
| Soluble in water
87
Prosthetic group
Non protein component
88
Describe a fibrous protein
Regular repetitive sequences of amino acids
| Insoluble in water
89
What do fibrous proteins do
Form fibres which form a structural role
90
Characteristics of amylose
Coils into spiral shape
Binds on carbons 1 and 4
Hydroxyl group on carbon 2 for hydrogen bonds
91
Globular proteins tend to fold up into what shape
Sphere
92
Two enzymes that carry out dna replication
DNA helicase
| DNA polymerase
93
What is a nucleotide made up of
Pentose monosaccharide
Phosphate Group
Base
94
How many hydrogen bonds does A & T form
2
95
How many hydrogen bonds can C & G/U make
3
96
What is Adenosine triphosphate made up of
Base
Pentose sugar (ribose)
3 phosphate groups
97
Releasing energy through ATP is what reaction
Hydrolysis
98
Storing energy through ATP is what reaction
Condensation
99
DNA vs RNA
differences- dna 2 long strands vs 1 short strand
Deoxyribose vs ribose
A,C, G and T vs A, C, G and U
100
Define transcription
Copying of the genetic code from DNA into mRNA
101
Define translation
Assembly of a polypeptide from the genetic code on the mRNA
102
Where is the codon and anti codon
Codon on ribosome
| Anticodon on tRNA
103
What is the triplet code
Sequence of 3 based- the codon
104
Sense strand
Runs from 5’ to 3’
105
Antisense strand
Acts as template strand
| Runs from 3’ to 5’
106
In an amino acid which two groups combine to form a peptide link?
1 and 3
107
What does ethanol do to a lipid
Dissolves it
108
what is the formulae of a fatty acid
Cn H2n
