Biological Molecules Flashcards
1
Q
What is a monomer?
A
Smaller units which can create larger moldcules
2
Q
What is a polymer?
A
Made from lots of monomers bonded together
3
Q
What are three examples of monomers?
A
- Glucose
- Amino acid
- Nucleotide
4
Q
What are there examples of polymers?
A
- Starch, cellulose and glycogen
- Proteins
- DNA and RNA
5
Q
What is a condensation reaction?
A
- Joining of two molecules
- Creates a chemical bond
- Removes water
6
Q
What is a hydrolysis reaction?
A
- Breaking of a chemical bond between two molecules
- Uses water
7
Q
What are three monosaccharides?
A
- Glucose
- Fructose
- Galactose
8
Q
What are three disaccharides?
A
- Sucrose
- Maltose
- Lactose
9
Q
What are three polysaccharides?
A
- Starch
- Cellulose
- Glycogen
10
Q
What are disaccharides joined by?
A
- Glycosidic bond
- Condensation reaction
11
Q
Where is starch found and what is its function?
A
- Plants
- Stores glucose
12
Q
Where is cellulose found and what is its function?
A
- Plants
- Structural strength
13
Q
Where is glycogen found and what is its function?
A
- Animals
- Stores glucose
14
Q
How are polysaccharides formed?
A
Condensation reactions
15
Q
What monomer is starch made up of?
A
Alpha glucose
16
Q
What monomer is cellulose made up of?
A
Beta glucose
17
Q
What monomer is glycogen made up of?
A
Alpha glucose
18
Q
What is the structure of starch and how does this benefit it?
A
- Amylose - unbranched helix
- Amylopectin - branched
- Helix compacts it so can fit lots of glucose
- Branched structure increases surface area for hydrolysis
- Insoluble
19
Q
What is the structure of cellulose and how does this benefit it?
A
- Long, straight chains
- Held together by hydrogen bonds
- Hydrogen bonds provide strength
- Insoluble so WP not affected
20
Q
What is the structure of glycogen and how does this benefit it?
A
- Highly branched
- Branches increase surface area for hydrolysis
- Insoluble
21
Q
What are two types of lipids?
A
- Triglycerides
- Phospholipids
22
Q
How are triglycerides and phospholipids similar?
A
- Both contain a glycerol molecule
- Both formed by condensation reactions
- Both contain ester bonds
23
Q
How are triglycerides and phospholipids different?
A
- Triglycerides have three fatty acid chains
- Phospholipids have two fatty acid chains and a phosphate group
24
Q
What are the properties of triglycerides?
A
- Energy storage in bonds
- High ratio of H:O, so acts as water source e.g. in camels
- Don’t affect water potential because they are large and hydrophobic (insoluble)
- Low mass so lots can be stored
25
What are the properties of phospholipids?
- Hydrophilic head attracts water but repels lipids
- Hydrophobic tail repels water but can attract lipids
- Heads faced towards water
26
How are dipeptides formed?
- Condensation reaction
- Two amino acids
- Peptide bonds
27
How are polypeptides formed?
- Condensation
- Many amino acids
- Peptide bonds
28
What is the induced fit model?
1. Substrate binds to enzymes active site
2. Enzyme changes shape slightly as substrate binds
3. Change in shape puts pressure on substrate so it breaks
4. Products produced
29
What five factors affect enzymes?
1. Temperature
2. pH
3. Substrate concentration
4. Enzyme concentration
5. Inhibitors
30
How does temperature affect enzyme activity?
**Lower Temperatures**
- Kinetic energy lower
- Less enzyme substrate complexes
**Higher temperatures**
- Enzymes denature
- Active site changes shape
- Enzyme-substrate complexes can’t form
31
How does pH affect enzyme activity?
- Too high or too low interferes with charges in amino acids in active site
- Breaks bonds holding tertiary structure
- Active site changes shape
32
How does substrate and enzyme concentration affect enzyme activity?
- Insufficient substrate makes reaction slower as less E-S complexes
- Insufficient enzymes means active sites become saturated faster
33
What do competitive inhibitors do?
- Same shape as the substrate
- Bind to the active site
- Prevents enzyme substrate complexes
- Can be knocked out of place if a substrate concentration is high
34
What do non-competitive inhibitors do?
- Bind to the allosteric site
- Causes the active site to change shape.
- No enzyme substrate complexes
- Substrate can no longer bind regardless of how much is added
35
What is the test for starch?
1. Add iodine
2. Positive test observation = solution turns orange to blue/black
36
37
What is the test for reducing sugars?
1. Add Benedict’s reagent and heat
2. Solution turns from blue to brick red.
38
What is the test for non-reducing sugars?
1. Following negative Benedict’s test reagent remains blue
2. Add acid and boil
3. Cool solution and add alkali to neutralise
4. Add Benedict’s reagent and heat
5. Solution turns blue to brick red
39
40
What is the test for proteins?
1. Add blurry
2. Positive test should turn blue to purple
41
What is the test for lipids?
1. Dissolve sample in ethanol
2. Add distilled water
3. White emulsion forms
42
What does DNA do?
- Codes for the sequence of amino acids in primary structure
- Determines final 3D structure and function of protein
43
How are polynucleotides formed?
- Formed by condensation reactions
- Have phosphodiester bonds between them
44
How does DNA differ to RNA?
-RNA is made up of ribonucleic acid
- DNA is deoxyribonucleic acid
- RNA is single stranded
- DNA is double stranded
- RNA is short
45
What is the function of RNA?
To transfer genetic code from DNA in the nucleus to the ribosomes
46
What is the function of rRNA?
Combines with proteins to create ribosomes
47
What is the first step of semi-conservative replication?
- DNA helicase breaks hydrogen bonds between complementary base pairs
- DNA double helix unwinds
48
What is the second step of semi-conservative replication?
- Each of the separated DNA strands acts as a template
- Free floating DNA nucleotides are attracted to complementary base pairs on template strands
49
What is the third step of semi-conservative replication?
- Adjacent nucleotides joined together by condensation reactions
- Forms phosphodiester bonds
- DNA polymerase catalyses joining together of strands
50
What is the fourth step of semi-conservative replication?
New DNA strand contains one strand of parental DNA and one newly synthesised strand
51
How is ATP made?
- During respiration
- Formed from ADP and Pi
- Requires ATP hydrolase
52
What is phosphorylation?
- ATP transfers energy to other compounds
- Pi released during hydrolysis of ATP can be bonded to different compounds to make them more reactive
- Happens to glucose at the start of respiration in glycolysis
53
What are the five key properties of water?
1. It is a metabolite - involved in chemical reactions e.g. condensation and hydrolysis reactions
2. Important solvent in reactions e.g. in phloem and xylem
3. High heat capacity so buffers temperatures
4. Large latent heat of vaporisation so provides cooling effect with loss of water via evaporation
5. Strong cohesion between molecules so supports xylem and provides surface tension
54
What is the role of hydrogen ions?
- Alters pH of solutions and impact enzyme and Hb function
- Play a role in chemiosmosis
- Respiration
- Photosynthesis
55
What is the role of iron ions?
Component of Hb in transport of oxygen
56
What is the role of sodium ions?
- Involved in co-transport of glucose and amino acids
- Generates action potentials
57
What is the role of phosphate ions?
- Component of DNA
- Component of ATP
