1.0 Biological Molecules Flashcards
1
Q
What is a monomer?
A
A single molecule that makes up larger molecules called polymers
2
Q
What is a polymer?
A
A larger molecule made up of multiple smaller molecules called monomers
3
Q
Name examples of monomers
A
Monosaccharides, amino acids, nucleotides
4
Q
What reaction joins monomers together?
A
Condensation reaction
5
Q
What happens in a condensation reaction?
A
Two monomers are chemically bonded together and water is formed as a by-product
6
Q
What reaction takes place when biological molecules are separated?
A
Hydrolysis reaction
7
Q
What happens in a hydrolysis reaction?
A
Two monomers are separated by breaking up a chemical bond, where water is used up in the reaction
8
Q
What are larger complex carbohydrates made from?
A
Monosaccharides
9
Q
What reaction forms the bond between monosaccharides?
A
Condensation reaction
10
Q
What are common monosaccharides?
A
Glucose, galactose, and fructose
11
Q
What bond forms when two monosaccharides join?
A
Glycosidic bond
12
Q
What is a disaccharide?
A
Two monosaccharides bonded together by a glycosidic bond
13
Q
How is a disaccharide formed?
A
A condensation reaction between two monosaccharides
14
Q
What is maltose formed from?
A
Two glucose molecules
15
Q
What is sucrose formed from?
A
Glucose and Fructose
16
Q
What is lactose formed from?
A
Glucose and galactose
17
Q
What are the two isomers of glucose?
A
Alpha glucose and beta glucose
18
Q
What is the difference between alpha and beta glucose?
A
Alpha has the OH group below carbon one while Beta has the OH group on top
19
Q
What is a polysaccharide?
A
Complex carbohydrate formed from the condensation reactions of many monosaccharides
20
Q
What is glycogen and what is it made of?
A
A polysaccharide made from many alpha glucose molecules
21
Q
What is starch and what is it made from?
A
A polysaccharide made from many alpha glucose molecules
22
Q
What is cellulose and what is it made from?
A
A polysaccharide made from many beta glucose molecules
23
Q
What is the purpose of glycogen?
A
Insoluble store of energy in animals
24
Q
What is the purpose of starch?
A
Insoluble store of energy in plants and animals energy source for animals
25
What is the purpose of cellulose?
Insoluble structural molecule for plants, especially for their cell walls
26
What is the structure of glycogen?
Heavily branched polymer of alpha glucose molecules, linked at 1-4 glycosidic bonds and branched at1-6 glycosidic bonds
27
How is glycogens structure related to its function?
1. Insoluble so cannot diffuse out of cells
2. Compact so lots is stored in a small space
3. Highly branched so can be acted on simultaneously by enzymes
28
What is the structure of starch?
Lightly branched polymer of alpha glucose molecules, linked at 1-4 glycosidic bonds and branched with 1-6 glycosidic bonds
29
How is starch’s structure related to its function?
1. Large so doesn’t diffuse out of cells
2. Compact so lots stored in a small space
3. Hydrolyses to from glucose easily so can be used for respiration
4. Branched so enzymes can act on it simultaneously
30
What is the structure of cellulose?
Straight lengths of polymers made of beta glucose, bonded with 1-4 glycosidic bonds
31
How are monosaccharides in cellulose arranged?
Alternative molecules are turned upside down
32
How is celluloses structure related to its function?
1. Chains run parallel to each other and are cross linked by hydrogen bonds which add strength
2. Molecules are grouped to form microfibrils
33
Based on the arrangement of cellulose molecules, explain why cell walls provide strength and support to plants
- cellulose molecules form hydrogen bonds with each other to make microfibrils
- microfibrils join to make macrofibrils
- macrofibrils join to make fibres
- fibres are insoluble ands tough
34
What are examples of reducing sugars?
All monosaccharides and some disaccharides
35
What is an example of a non-reducing sugar?
Sucrose
36
What does the Benedict’s test test for?
Reducing sugars
37
Describe the test for reducing sugars
1. Add equal volumes of the sample and Benedict’s reagent
2. Gently heat for five minutes
3. If reducing present colour should change from blue to brick red
38
Describe the test for non-reducing sugars
1. Carry out reducing sugar test
2. Add equal volume of sample and HCL then slowly add NAHCO3
3. Retest by gently heating for five minutes, if sugar present then colour should change from blue to brick red
39
How can we test for starch?
Iodine solution turns from orange to blue/black
40
How can we use a calorimeter to do a quantitative Benedict’s test?
1. Calorimeter measure the absorbance or transmission of light by a coloured solution
2. More concentrated solution = more light absorbed
3. Compare to data table or calibration curve
41
What is the role of lipids?
1. Source of energy
2. Waterproofing
3. Insulation
4. Protection
42
What are the two main groups of lipids?
Triglycerides and phospholipids
43
What are the components of a triglyceride?
1 glycerol molecule and 3 fatty acids bonded by a condensation reaction
44
How is the structure of a triglyceride related to their properties?
1. High ratio of energy storing C-H bonds
2. Low mass to energy ratio so good storage molecules
3. Large and non-polar so insoluble in water
4. High ratio of H to O atoms so release water when oxidised
45
What reaction occurs to form a triglyceride?
Condensation reaction where three water molecules are produced
46
What bond forms between a fatty acid and a glycerol molecule?
Ester bond
47
What is an R group?
A long chain of carbon atoms with attached hydrogen atoms
48
How can the R group of a lipid vary?
Can be saturated or unsaturated
49
What is a saturated R group?
Single bonds only between carbon atoms
50
What is an unsaturated R group?
One or more double bond between carbon atoms
51
Why do oils contain unsaturated triglycerides?
Causes the molecules to kink/bend
52
What does monounsaturated and polyunsaturated mean?
Mono = one double bond
Poly = multiple double bonds
53
what does having unsaturated R groups do to the fluidity of the triglycerides?
Causes a kink which makes the chain not lie as close together, they Hereford can’t hydrogen bonds and become solid
54
Describe the structure of a phospholipid
A hydrophobic tail which orients away from water but mixes with fat and a hydrophilic head which interacts with water
55
What does hydrophilic and hydrophobic mean?
Hydrophilic = repels water
Hydrophobic = will dissolve in water
56
What will a phospholipid do if placed in water
Will sit on the water, head down and tails up. Or form a sphere with heads in the water and tails inside being protected
57
Describe the steps in identifying lipids and state the positive result
1. Mix sample with ethanol
2. Mix solution with water and shake
3. white emulsion formed = lipid present
58
What are the monomers of proteins?
Amino acids
59
List out the elements that make up proteins
Carbon, Hydrogen, Oxygen, Nitrogen, Sulphur
60
What groups make p an amino acid?
1. Amine group (NH2)
2. Carboxyl group (COOH)
3. R group
61
What reaction joins two amino acids together?
Condensation reaction
62
What bond holds two amino acids together?
Peptide bond
63
What is formed when two amino acids join by condensation reaction?
Dipeptide
64
What is formed when many amino acids bond by condensation reaction?
Polypeptide
65
What is a functional protein?
A protein that has a particular role, it is not involved in structure
66
Describe the four structures within a polypeptide
1. Primary - the amino acid sequence
2. Secondary - alpha helix or beta pleated sheet
3. Tertiary - Folding into a 3D shape
4. Quaternary - multiple polypeptide chains
67
State the three bonds involved within the tertiary structure of a polypeptide
1. Hydrogen
2. Ionic
3. Disulfide
68
What is the solution used to test for the presence of proteins?
Biuret solution
69
Describe the test for proteins
1. Add equal volumes of sample and biuret reagent
2. Mix gently
3. Colour change from blue to purple
70
What are metabolic reactions?
the sum of all reactions within an organism
71
What are anabolic and catabolic reactions?
Anabolic = Building up larger molecules
Catabolic = Breaking down larger molecules
72
What are enzymes?
Biological catalysts which speed up chemical reactions
73
Name the energy required for a chemical reaction to start
Activation energy
74
Describe the lock and key model of enzyme action
1. Active site and substrate exactly complimentary
2. Substrate binds to active site to form an enzyme-substrate complex
75
Describe the induced fit model?
Active site changed shape slightly to fit the substrate to form an enzyme substrate complex
76
What creates the active site?
Tertiary structure
77
What does enzyme specificity mean?
Enzymes only work with one substrate
78
What factors are involved in the rate of enzyme controlled reactions?
1. Temperature
2. pH
3. Enzyme concentration
4. Substrate concentration
79
How does enzyme concentration affect the rate of reaction?
Higher enzyme concentration means a higher rate of reaction due to their being a larger amount of active sites for the substrates to bind to, substrate concentration will become the limiting factor
80
How does substrate concentration affect the rate of reaction?
Higher substrate concentration means a higher rate of reaction due to more active sites being filled, enzyme concentration will eventually become the limiting factor
81
How does a competitive inhibitor affect the working of an enzyme?
Have a similar shape to the substrate, so competes for the active site and bind to it so the substrate cannot react
82
How does a non-competitive inhibitor affect the rate of reaction?
Binds to the allosteric site which changes the shape of the active site so he substrate can no longer fit nd form an enzyme substrate complex
