Biological Molecules Flashcards
(108 cards)
1
Q
What are monomers?
A
Monomers are smaller units which can create larger molecules
2
Q
What are polymers?
A
Polymers are made from lots of monomers bonded together
3
Q
Name the three types of monomers:
1)
2)
3)
A
1) Glucose
2) Amino Acid
3) Nucleotide
4
Q
Name three types of polymers?
1)
2)
3)
A
1)
a) Starch
b) Cellulose
c) Glycogen
2) Protein
3) DNA and RNA
5
Q
What are the two main chemical reactions?
A
1) Condensation reaction
2) Hydrolysis reaction
6
Q
What is a condensation reaction?
A
It is the joining of two monomers which forms a chemical bond through the elimination of water
7
Q
What is a hydrolysis reaction?
A
It is the breaking of the chemical bond between two monomers through the addition of water
8
Q
What elements do carbohydrates contain?
A
C, H, O
Carbon, Hydrogen , Oxygen
9
Q
What are the three types of carbohydrates?
1)
2)
3)
A
1) Monosaccharides
2) Disaccharides
3) Polysaccharides
10
Q
What are three examples of monosaccharides?
1)
2)
3)
A
1) Glucose
2) Fructose
3) Galactose
11
Q
What are the three examples of disaccharides?
1)
2)
3)
A
1) Sucrose
2) Maltose
3) Lactose
12
Q
What are the three examples of polysaccharide?
1)
2)
3)
A
1) Starch
2) Cellulose
3) Glycogen
13
Q
What are the two types of glucose?
1)
2)
A
1) Alpha (α) glucose:
2) Beta (β) glucose:
14
Q
Describe structure of α glucose:
A
The H is at the top
The OH is at the bottom
15
Q
Describe the structure of β glucose:
A
The OH is at the top
The H is at the bottom
16
Q
What are α glucose and β glucose examples of?
A
Isomers
17
Q
What is an isomer?
A
Same molecular formula different structure
18
Q
What is the chemical formula of α glucose and β glucose?
A
C₆H₁₂O₆
19
Q
What is the test for reducing sugars?
A
1) Add Benedict’s reagent and heat
2) A positive test observation = solution turns from blue to green, yellow , orange or brick red
Boys Get Yummy Oranges Regularly
The more red the higher the concentration of reducing sugars
20
Q
What is the test for non-reducing sugars?
A
1) Add acid and boil - (this is acid hydrolysis)
2) Cool the solution then add an alkali to neutralise
3) Add Benedict’s reagent and heat
4) A positive test observation = solutions turns from blue to orange or brick red
21
Q
What are disaccharides made from?
A
- Made of two monosaccharides
- Joined together by a glycosidic bond
- Formed through a condensation reaction
22
Q
What are the three condensation reactions that form disaccharides:
A
Glucose + glucose → Maltose + water
Glucose + galactose → Lactose + water
Glucose + fructose → Sucrose + water
23
Q
What are polysaccharides made from?
A
- Condensation reaction between many glucose monomers
24
Q
What monomer is starch made from?
A
α glucose
25
What are the bonds in starch?
1-4 glycosidic bonds in amylose
1-4 & 1-6 in amylopectin
26
What is the function of starch?
It is a store of glucose
27
Where is starch found?
In plant cells (e.g. chloroplasts)
28
What two polymers is starch made of?
1) Amylose
2) Amylopectin
29
What is the structure of the polymer 'amylose' in starch?
An unbranched helix
30
What is the structure of the polymer 'amylopectin' in starch?
A branched molecule
31
What is the explanation for how starch's structure leads to its function?
* **Compact**: Helix can *fit a lot of glucose in* small amount of space
* **Branched:** Increase *the surface area* for quick hydrolysis back to glucose
* **Insoluable**: Won't affect water potential
32
What is the test for starch?
1) Add iodine
2 ) A positive test observation = solutions turns from orange to blue/black
33
What is monomer is cellulose made from?
β glucose
34
What bond is between monomers in cellulose?
1-4 glycosidic bonds
35
What is the function of cellulose?
It gives structural strength for the cell wall
36
Where is cellulose found?
In plants (the cell wall)
37
What is the structure of cellulose?
* Long straight chains
* Chain are held in parallel by many hydrogen bonds to form fibrils
38
What is the explanation for how the structure of cellulose leads to its function?
* Many hydrogen bonds provide collective strength
* Insoluble: Won't affect water potential
39
What monomer is glycogen made from?
α glucose
40
What is the bonds between monomers in glycogen?
1-4 & 1-6 (higher) glycosidic bonds
41
What is the function of glycogen?
To store glucose
42
Where is glycogen found?
In animals (mainly liver & muscle cells)
43
What is the structure of glycogen?
A highly branched molecule
44
What is the explanation for how the structure of glycogen leads to it function?
* Branched structure: Increase surface area for quick hydrolysis back into glucose
* Insoluble: Won't affect water potential
45
What is the structure of a triglyceride?
A glycerol and three fatty acids
46
What is the structure of a phospholipid?
* Two fatty acids
* A glycerol
* A phosphate group
47
How are triglycerides formed?
By a condensation reaction between a glycerol molecule and three fatty acids
48
How many condensation reactions should there be when a triglyceride is formed?
There will be 3 condensation reactions because there are three fatty acids that will join to a glycerol
49
What is the bond formed between triglycerides?
An ester bond
50
What is an R-group?
They are fatty acids
51
What are the two types of fatty acid?
* Saturated
* Unsaturated
52
What is a saturated fatty acid?
The hydrocarbon chain has only single bonds between carbons
C-C
53
What is a unsaturated fatty acid?
The hydrocarbon chain has at least one double bond between carbons
C=C
54
How does the structure of triglycerides relate to their properties?
**High energy storage: **Many C-H bonds store lots of energy.
**Metabolic water source:** High hydrogen :oxyen ratio allows water release on oxidation (e.g., useful for camels).
**Insoluble:** Large and hydrophobic, so don’t affect osmosis or water potential.
**Efficient storage:** Low mass allows lots to be stored without adding bulk.
55
What are phospholipids made of?
* 1 glycerol molecule
* 2 fatty acids chains
* 1 phosphate group (attached to the glycerol)
56
How do the two fatty acids bond to glycerol in a triglyceride?
By two condensation reactions, forming two ester bonds.
57
How does the structure of phospholipids relate to their properties?
Hydrophilic head (phosphate group) attracts water, repels fat.
Hydrophobic tails (fatty acids) repel water, mix with fat.
Polar molecule with two charged regions.
In water, form a phospholipid bilayer: heads face water, tails face inward.
58
What is the test for lipids?
1) Add ethanol, then shake.
2) Add water and shake again.
3) A positive test observation = a white emulsion forms
59
What are the monomers of proteins?
Amino acids
60
How do dipeptides form?
When two amino acids are joined together by a condensation reaction
61
How do polypeptides form?
Polypeptides are formed by a condensation reaction between many amino acids
62
What are the four levels of structure in a protein?
1) Primary structure
2) Secondary structure
3) Tertiary structure
4) Quaternary structure
63
What is the primary structure?
It is the sequence of amino acids in the polypeptide chain (polymer)
64
What is the secondary structure?
The sequence of amino acids causes parts of a protein molecule to bend into α helix or fold into β pleated sheets
* Hydrogen bonds hold the secondary structure
65
What is the tertiary structure?
* The further folding of the secondary structure
* To form a unique 3D shape
* Held in place by hydrogen bonds, ionic bonds and disulfide bridges
66
What is the quaternary structure?
A protein made up of more than one polypeptide chain
67
What is the test for proteins?
1) Add biuret solution
2) A positive test observation = solution turns from blue to purple
68
What are enzymes?
Enzymes are tertiary structure proteins which lower the activation energy of the reactions they catalyse
69
What is the active site?
The active site is specific and unique in shape due to the specific folding and bonding in the tertiary structure of the protein
70
What are the location of the bonds determined by in enzymes?
The primary structure
71
What is the model of enzyme action?
The model to explain how enzymes function changes over time
72
What is the induced fit model?
*When the enzyme’s active site is induced or slightly changes shape to mould around the substrate
*When the enzyme-substrate complex occurs, due to the enzyme moulding around the substrate it puts strain on the bonds and therefore lowers the activation energy
73
What factors affect enzymes?
1) Temperature
2) pH
3) Substrate concentration
4) Enzyme concentration
5) Inhibitors
74
How does temperature affect enzymes?
* If the temperature is too low there is not enough kinetic energy for successful collisions between the enzyme and substrate.
*So fewer enzyme substrate complexes are formed
*If the temperature is too high enzymes denature, the active site changes shape
*So enzyme substrate complexes cannot form
*The rate decreases
75
How does pH affect enzymes?
* If the pH is too low or too high it will interfere with the charges in the amino acids in the active site.
* This can break down the bonds holding the tertiary structure in place
*Therefore the active site changes shape
*Therefore the enzyme denatures and fewer enzyme-substrate complexes form
Different enzymes have different optimal pH
76
How does substrate and enzyme concentration affect enzymes?
*If there is insufficient substrate, then the reaction will be slower as there are fewer collisions between the enzyme and substrate
*If there is insufficient enzymes, then the enzyme active sites will become saturated with substrate and unable to work any faster
77
What are the two types of enzyme inhibitors?
1) Competitive inhibitors
2) Non-competitive inhibitors
78
Competitive inhibitors:
*
*
*
* Same shape as the substrate
* Binds to the active site
* Prevents enzyme-substrate complexes forming
If you add more substrate it will flood/out compete the inhibitor, knocking them out the active site
79
Non-competitive inhibitors:
*
*
*
* Binds to an alternative site on the enzyme or allosteric site
* Causes the active site to change shape
* No enzyme- substrate complexes form
The substrate can no longer bind, regardless of how much substrate is added
80
What does DNA code for in proteins?
The sequence of amino acids in the primary structure, determining the protein's 3D structure and function.
81
How is the genetic code preserved in cells?
Each cell contains a copy that can be passed on without damage.
82
What is the structure of the DNA polymer?
A double helix.
83
What are the three components of a DNA nucleotide?
A nitrogenous base (A, T, C, G), a deoxyribose sugar, and a phosphate group.
84
What is the polymer of nucleotides called?
A polynucleotide.
85
How are nucleotides joined in a polynucleotide?
By condensation reactions forming phosphodiester bonds between the sugar and phosphate.
86
What bonds join the two DNA strands together?
Hydrogen bonds between complementary base pairs.
87
Which bases pair together in DNA?
Adenine with Thymine, and Cytosine with Guanine.
88
What components make up RNA nucleotides?
* Ribose sugar
* A nitrogenous base (A, U, C, G)
* A phosphate group.
89
How does RNA differ from DNA?
* RNA is shorter
* Ribose sugar not deoxyribose
* RNA single-stranded
*Uses uracil instead of thymine.
90
When does DNA replication occur?
Before cell division by mitosis or meiosis.
91
What is the name of the process by which DNA replicates?
Semi-conservative replication.
92
What does semi-conservative replication mean?
Each new DNA molecule has one original strand and one newly synthesized strand.
93
What is required for semi-conservative replication?
1) Free nucleotides
2) Energy
3) DNA template strands
4) Enzymes.
94
What are the steps in semi-conservative replication?
1) The enzyme ‘DNA Helicase’ breaks the hydrogen bonds that link the base pairs of DNA
2) The double helix unwinds and separates into its 2 strands.
3) Free nucleotides that have been activated bind to their complementary bases
4) The enzyme ‘DNA Polymerase’ joins nucleotides through a condensation reaction which makes phosphodiester bonds.
5) All the nucleotides are joined to form a polynucleotide chain
6) Two identical molecules of DNA are formed
95
What is the role of DNA helicase in replication?
It breaks hydrogen bonds between base pairs and unwinds the DNA double helix.
96
What does DNA polymerase do during replication?
Joins nucleotides with phosphodiester bonds through condensation reactions.
97
Who proved the semi-conservative model of DNA replication?
Meselson and Stahl.
98
What does ATP stand for?
Adenosine Triphosphate.
99
What type of molecule is ATP?
A nucleotide derivative.
100
How is ATP made during respiration?
Process name: Condensation reaction
Enzyme involved: ATP synthase
What happens:
ADP + Pi —(ATP synthase)—> ATP + H₂O
101
How is energy released from ATP?
Process name: Hydrolysis reaction
Enzyme involved: ATP hydrolase
What happens:
ATP —(ATP hydrolase)—> ADP + Pi + energy
102
What is phosphorylation in terms of ATP?
The addition of an inorganic phosphate to another compound to make it more reactive.
103
Why is ATP important in cells?
It is an immediate energy source for biological processes.
104
Where are inorganic ions found in organisms?
In solution in cytoplasm and body fluids.
105
What is the role of hydrogen ions (H⁺)?
They lower pH and affect enzyme and haemoglobin function; also important in chemiosmosis.
106
What is the role of iron ions (Fe²⁺)?
They are part of haemoglobin and help transport oxygen.
107
What is the role of sodium ions (Na⁺)?
Involved in co-transport of glucose and amino acids, and in generating action potentials.
108
What is the role of phosphate ions (PO₄³⁻)?
Form phosphodiester bonds in DNA and make ADP more reactive in ATP.
