Biological Molecules Flashcards
1
Q
What is a monomer?
A
Small basic molecular units
2
Q
What is an example of a monomer?
A
Monosaccharides, Amino acids and Nucleotides
3
Q
What is a polymer?
A
Large complex molecules composed of long chains of monomers joined together
4
Q
What is an example of a polymer?
A
Carbohydrates, Proteins and Nucleic acids
5
Q
What type of sugar is glucose?
A
Hexose
6
Q
How many types of glucose are there?
A
2
7
Q
What are the names of the types of glucose?
A
Alpha-glucose and Beta-glucose
8
Q
What is a condensation reaction?
A
When 2 molecules join together with the formation of a new chemical bond, releasing a water molecule
9
Q
Condensation reactions join which molecules?
A
Monosaccharides
10
Q
What type of chemical bond forms between 2 monosaccharides?
A
Glycosidic Bonds
11
Q
What is formed when 2 monosaccharides join together?
A
Disaccharides
12
Q
Which 2 molecules make maltose?
A
Alpha glucose and Alpha Glucose
13
Q
What is sucrose made from?
A
Alpha glucose and Fructose
14
Q
Which 2 molecules make lactose?
A
Alpha glucose and Galactose
15
Q
What is a hydrolysis reaction?
A
When 2 molecules are broken apart using a water molecule
16
Q
What is broken down by hydrolysis to form monosaccharides?
A
Carbohydrates
17
Q
What is the test for reducing sugars?
A
Add Benedict’s reagent to a sample and heat.If the test is positive, it will turn brick red, if it’s negative, it’ll stay blue
18
Q
What is test for non reducing sugars?
A
Add dilute HCL to the sample and heat. Neutralise solution using sodium hydrogencarbonate. Then add Benedict’s reagent. If present brick-red.
19
Q
What is a polysaccharide?
A
Formed when more than 2 monosaccharides are joined together by condensation reactions
20
Q
What is the function of starch?
A
Used as an energy store
21
Q
What makes up starch?
A
Amylose and Amylopectin
22
Q
What is the structure of amylose?
A
Long, unbranched chain of alpha-glucose; has a coiled structure, making it compact and good for storage
23
Q
What is the structure of amylopectin?
A
Long, branched chain of alpha-glucose, side branches allow the enzymes that break the molecule down to access the bonds easily, meaning glucose can be released quickly
24
Q
What are the features of starch?
A
Insoluble in water, doesn’t affect water potential so water doesn’t enter the cell, which would make them swell
25
How do you test for starch?
Add iodine
If present turns from brown/orange to dark blue/black
26
What do animals store glucose as?
Glycogen
27
What structure is glycogen similar to?
Amylopectin, except it has more side branches, meaning stored glucose can released quickly, very compact
28
What is a major component of cell walls in plants?
Cellulose
29
What is the structure of cellulose?
Long unbranched chains of beta glucose
30
What is formed when beta glucose molecules bond?
Straight cellulose chains
31
What are the advantages of cellulose chains?
They're linked together by hydrogen bonds to form microfibrils, providing structural support for cells
32
What is the structure of a triglyceride?
3 Fatty Acid Chains and 1 Glycerol
33
What are triglyceride tails made of?
Hydrocarbons
34
Are the triglyceride tails hydrophobic or hydrophilic?
Hydrophobic
35
Are lipids soluble or insoluble in water?
Insoluble
36
Triglycerides are formed by what type of reaction?
Condensation
37
What is a saturated fatty acid?
A fatty acid with no double bonds between the carbon atoms
38
What is an unsaturated fatty acid?
A fatty acid with at least one double bond between the carbon atoms
39
What's the difference between a triglyceride and a phospholipid?
A triglyceride has 3 fatty acid tails. A phospholipid has 2 fatty acid tails and a phosphate group attached to the glycerol
40
Is the phosphate group hydrophilic or hydrophobic?
Hydrophilic
41
What are triglycerides used as?
Energy Storage in molecules
42
What do the hydrocarbon tails of triglycerides contain which is useful for us?
Chemical energy
43
Lipids contain how much more energy than carbohydrates?
Double
44
Are triglycerides insoluble or soluble?
Insoluble, they don't affect the water potential
45
How do triglycerides act in cells?
They clump together as insoluble droplets, the tails face inwards and the heads face out
46
What do phospholipids do?
Make up the bilayer of cell membranes, meaning they control what enters and leaves the cell
47
What do phospholipids form?
A double layer, heads outside and tails inside, forming a barrier against water soluble substances
48
How do you do the emulsion test?
Add ethanol then shake the test substance with ethanol for a minute so it dissolves and pour the solution in water. Any lipid will show as a milky emulsion
49
What are the monomers of protein?
Amino acids
50
How is a polypeptide formed?
Formed by more than 2 amino acids join together
51
How are proteins made up?
Made up of one or more polypeptides
52
How many amino acids do all living things have?
20
53
What is the name of the bonds formed between 2 amino acids?
Peptide Bonds
54
Protein Structure: Primary Structure
Sequence of amino acids in the polypeptide chain
55
Protein Structure: Secondary Structure
Hydrogen bonds form between the amino acids in the chain, making it coil into an alpha helix or a beta pleated sheet
56
Protein Structure: Tertiary Structure
The coiled or folded chain is coiled further, more hydrogen and ionic bonds form.
57
When do disulfide bridges form?
Whenever 2 molecules of cysteine come close together
58
Protein Structure: Quaternary Structure
Made of several different polypeptide chains, held together by different bonds
59
How do you do the biuret test? (Test for proteins)
Add biuret solution if present turns lilac/purple
60
What are enzymes?
Biological Catalysts
61
What do enzymes do?
They catalyse metabolic reactions at both a cellular level and across the whole organism
62
What can enzymes affect?
Structures in an organism (such as collagen production) and functions (such as respiration)
63
What makes each enzyme different?
Their active site, which has a specific shape
64
How are enzymes specific?
Their tertiary structure
65
Do enzymes slow down or speed up a reaction?
Speed up
66
How do enzymes speed up a reaction?
By lowering the activation energy
67
What is the lock and key model?
Where the substrate fits exactly into the enzyme
68
What is the induced fit model?
Where the substrate fits into the enzyme, then the enzyme changes it's shape slightly to lock the substrate even tighter to itself
69
What is it called when an enzyme and a substrate are joined together?
Enzyme-Substrate Complex
70
What happens if the tertiary structure of an enzyme is altered?
The shape of the active site will change, meaning the substrate won't be able to fit, meaning the enzyme is unable to carry out its function of catalyzing the substrate. It becomes denatured.
71
What determines the primary structure of a protein?
A gene
72
Why does temperature have such a large impact on enzyme activity?
Because each enzyme has its own optimum temperature, anything before that will decrease the rate of reaction and anything above that will result in bonds breaking and the enzyme becoming denatured
73
How does pH affect enzyme activity?
All enzymes have an optimum pH (usually 7), Above and below the optimum temperature messes up the ionic and hydrogen bonds that hold the tertiary structure in place, denaturing the enzymes
74
How does enzyme concentration affect enzyme activity?
The more enzyme molecules there are, the more likely there are to be collisions between enzyme and substrate molecules, forming more enzyme-substrate complexes
75
How does substrate concentration affect enzyme activity?
The more substrate molecules there are, the more likely there are to be collisions between enzyme and substrate molecules, forming more enzyme-substrate complexes
76
How can enzyme activity be inhibited by competitive inhibitors?
Competitive inhibitor molecules have a similar shape to substrate molecules, so will compete with the substrate to bind with the enzyme and block the active site. The higher the competitive inhibitor concentration, the more active sites are filled and less enzyme-substrate complexes are formed
77
How can enzyme activity be inhibited by non competitive inhibitors?
Non-competitive inhibitors bind to the enzyme away from its active site, causing the active site to change shape so substrate molecules can't bind to the enzyme
78
What is the structure of Alpha glucose?
OH group attached to the first carbon atom in alpha glucose is located on the same side as the –CH2OH group
79
What is the structure of Beta glucose?
OH group attached to the first carbon atom of in beta glucose is located on the opposite side from the –CH2OH group
80
What is the basic structure of a fatty acid?
Carboxyl group -COOH
Variable R group = hydrocarbon tail
81
What is the structure of amino acids?
Carboxyl group (-COOH), amine group (-NH2), R group (variable region) and hydrogen.
82
What are monosaccharides and disaccharides known as?
Sugars
83
What elements do all carbohydrates contain?
Carbon, Hydrogen and Oxygen
84
What is an isomer?
Two or more molecules that have the same molecular formula but a different arrangement of atoms.
85
What is the difference in the structure of alpha and beta glucose?
Alpha glucose order of OH - down down up down
Beta glucose order of OH - up down up down
86
What does the R group of the amino acid mean?
R group is the variable region that determines the amino acid.
87
How does increasing the temperature increase the rate of an enzyme-controlled reaction?
More heat means more kinetic energy = molecule move faster = substrate molecules more likely to collide with enzyme's active site .
Energy of collisions also increases = collisions more likely to result in a reaction.
88
What happens if the temperature is too high in an enzyme-controlled reaction?
The reaction will stop.
Rise in temperature makes enzymes vibrate more = at a too high temperature, vibrations can break some of the bonds that hold the enzymes shape = active site of the enzyme changes shape = substrate no longer fits = enzyme is denatured.
89
What does DNA stand for?
DeoxyriboNucleic Acid
90
What's the function of DNA?
Stores genetic information
91
What does RNA stand for?
RiboNuceleic Acid
92
What's the function of RNA?
Transfer genetic information from the DNA to the ribosomes
93
What's a nucleotide made up of?
A pentose sugar, a nitrogen containing organic base and a phosphate group
94
What are nucleotides?
Monomers that make up DNA and RNA
95
What's the name of the pentose sugar in DNA?
Deoxyribose
96
What are the 4 bases in DNA?
Adenine, Thymine, Cytosine and Guanine
97
What's the name of the pentose sugar in RNA?
Ribose
98
What's the difference between the bases in DNA and RNA?
In RNA, Thymine is replaced with Uracil
99
What is a polynucleotide?
A polymer of nucleotides
100
How do the nucleotides join together?
A condensation reaction between the phosphate group of one nucleotide and the pentose sugar of the other
101
What type of bond forms when a condensation reaction between the phosphate group of one nucleotide and the pentose sugar of the other occur?
Phosohodiester Bonds
102
What is the chain of pentose sugar and phosphates known as?
Sugar-Phosphate Backbone
103
What structure does DNA have?
Double Helix
104
How do the 2 strands in DNA join together?
Hydrogen bonding between the base pairs
105
What is complimentary base pairing?
Where a base can only join with a particular base
106
What base does adenine always pair with?
Thymine
107
What base does guanine always pair with?
Cytosine
108
How many hydrogen bonds form between adenine and thymine?
2
109
How many hydrogen bonds form between cytosine and guanine?
3
110
What is Semi-Conservative replication and what happens during it?
DNA helicase breaks the hydrogen bonds between the 2 complimentary bases on the polynucleotide strands, making the DNA unravel to form 2 single strands. Each original strand acts as a template for the new strand to be formed. Due to complimentary base pairing, free nucleotides are attracted to their complimentary exposed bases.Condensation reactions join the free nucleotides of the strands. This is catalysed by DNA polymerase. Hydrogen bonds form between the bases of the original and the new strands. Each new DNA molecule contains a new strand and an old strand.
111
What is a metabolite?
A substance involved in a metabolic reaction
112
What is a metabolic reaction?
A chemical reaction that happens in a living organism to keep it alive
113
What is water?
A metabolite
114
How does water help with temperature control?
It has a high latent heat of vaporization and a high specific heat capacity
115
Are water molecules cohesive?
Yes, they stick together very easily
116
Is water a polar molecule?
Yes, it has a slight delta negative charge on the side with oxygen, and a slight delta positive charge on the side with the hydrogen
117
What attraction is present between water molecules?
Hydrogen Bonding
118
Why does water have a high latent heat of vaporisation?
Because it takes a lot of heat/energy to break the hydrogen bonding between molecules
119
What can hydrogen bonds do?
Absorb a lot of energy
120
Why does water have a high specific heat capacity?
Because it takes a lot of energy to heat it up
121
How is water's high specific heat capacity useful?
The water inside organisms remains at a stable temperature, helping them to maintain constant body temperature
122
How is water a good solvent?
The partial charges will be attracted to the molecule, surrounding it completely, dissolving it
123
What is cohesion?
The attraction between molecules of the same type
124
What does strong cohesion help water to do? Why is it useful?
Helps water flow, it's useful because it can transport substances
125
What is ATP?
The immediate source of energy in a cell
126
What is the structure of ATP?
The nucleotide base adenine
A ribose sugar
Three phosphate groups.
127
What base is ATP made from?
Adenine
128
What base is ATP made from?
Adenine
129
Where is the energy in ATP stored?
High energy bonds between the phosphate groups
130
What is ATP broken down into?
ADP and Phosphate
131
What reaction breaks down ATP?
Hydrolysis
132
What enzyme catalyses the breakdown of ATP?
ATP hydrolase
133
What enzyme catalyses the resynthesis of ATP?
ATP synthase
134
When does the resynthesis of ATP happen?
During respiration and photosynthesis
135
What is an inorganic ion?
An ion which doesn't contain carbon
136
How many polypeptide chains is haemoglobin made up of?
4
137
What ion does haemoglobin have in the centre of the polypeptide chains?
Iron
138
What binds to the oxygen in haemoglobin?
The iron ions
139
What ion determines pH?
Hydrogen ions
140
Does a higher or lower concentration of hydrogen ions lower pH?
Higher
141
What type of reaction is affected by pH?
Enzyme Controlled
142
What do sodium ions do?
Help transport glucose and amino acids across membranes
143
What 3 molecules contain phosphate groups?
DNA, RNA and ATP
144
What do the phosphate groups in DNA and RNA do?
Allow nucleotides to join together to form polynucleotides
145
What does antiparallel mean?
Running in opposite directions
146
Each end of a DNA strand is slightly different in its structure, what are the 2 ends called.
3' (3 prime) and 5' 5(prime)
147
What did Meselson and Stahl show?
DNA is replicated using semi-conservative method
148
Which two isotopes did Meselsons and Stahls experiment use?
Heavy nitrogen (15N)
Light nitrogen (14N)
149
Outline Meselson and Stahl's experiment.
1) Two samples of bacteria were grown - one in a nutrient broth containing light nitrogen and one in broth of heavy nitrogen. As bac. reproduce, they took up nitrogen from broth, N became part of bac. DNA.
2) Sample of DNA taken from each batch of bac. spun in centrifuge. DNA from heavy nitrogen bac. settled lower down centrifuge tube, because its heavier.
3) Bac. grown in heavy nitrogen broth taken out and put in broth containing only 14N. Bac. left for one round of DNA replication, another DNA sample taken out and spun in centrifuge.
4) If replication conservative, 15N would still be together, would settle at bottom and 14N would settle at the top.
5) If replication semi-conservative, new bac. DNA molecules would contain one strand of old DNA containing 15N, and one strand of new DNA containing 14N. So DNA would settle between where light nitrogen DNA settled out and where heavy nitrogen DNA settled out.
6) DNA settled out in middle, showing that DNA molecules contained a mixture of heavy and light nitrogen. Bac. DNA had replicated semi-conservatively in the light nitrogen.
150
What does ATP stand for?
Adenosine triphosphate
