Biological Molecules Flashcards
1
Q
What is the common chemistry shared by all life on earth?
A
All life on earth shares a common chemistry.
2
Q
Define monomers.
A
Monomers are the basic building blocks of larger molecules.
3
Q
What are dimers?
A
Dimers are molecules formed from two monomers.
4
Q
What are polymers?
A
Polymers are large molecules made up of many monomers.
5
Q
What are carbohydrates?
A
Carbohydrates are organic compounds made of carbon, hydrogen, and oxygen.
6
Q
What is the general formula for carbohydrates?
A
Cₓ(H₂O)ᵧ
7
Q
List the types of carbohydrates.
A
- Monosaccharides
- Disaccharides
- Polysaccharides
8
Q
What are monosaccharides?
A
Monosaccharides are the simplest form of carbohydrates, consisting of single sugar molecules.
9
Q
What are disaccharides?
A
Disaccharides are carbohydrates formed by the combination of two monosaccharides.
10
Q
What are polysaccharides?
A
Polysaccharides are long chains of monosaccharides linked together.
11
Q
What is glucose?
A
Glucose is a monosaccharide and the main energy source in most cells.
12
Q
What is the molecular formula of glucose?
A
C₆H₁₂O₆
13
Q
What is the difference between α-glucose and β-glucose?
A
α-glucose has a different structural arrangement compared to β-glucose, making them structural isomers.
14
Q
What is the structure of fructose?
A
Fructose is a very sweet and highly soluble monosaccharide found in fruits and nectar.
15
Q
What is the structure of galactose?
A
Galactose is less soluble and found in cell membranes.
16
Q
What is a glycosidic bond?
A
A glycosidic bond is a type of covalent bond that links monosaccharides together.
17
Q
What type of reaction forms disaccharides?
A
Condensation reaction.
18
Q
What is hydrolysis?
A
Hydrolysis is the reaction that breaks down disaccharides into monosaccharides using water.
19
Q
Name three disaccharides.
A
- Maltose
- Sucrose
- Lactose
20
Q
What is starch?
A
Starch is a polysaccharide that serves as an energy store in plants.
21
Q
What is glycogen?
A
Glycogen is a polysaccharide that serves as an energy store in animals.
22
Q
What is cellulose?
A
Cellulose is a polysaccharide that provides structural support in plant cell walls.
23
Q
What is the role of starch in plants?
A
Starch acts as an energy store in plants.
24
Q
What is the role of cellulose in plants?
A
Cellulose provides strength and rigidity to plant cell walls.
25
What does the iodine test indicate?
The iodine test indicates the presence of starch.
26
What is the result of a positive Benedict's test?
A positive Benedict's test results in an orange or brick red precipitate.
27
What is the purpose of a colorimeter in sugar testing?
A colorimeter measures the amount of light absorbed by a solution to quantify sugar concentration.
28
What happens to the solution in a negative Benedict's test?
The solution remains blue if no reducing sugar is present.
29
What is the difference between reducing and non-reducing sugars?
Reducing sugars can donate electrons, while non-reducing sugars cannot without hydrolysis.
30
Fill in the blank: A condensation reaction joins two monosaccharides and releases _______.
water
31
What type of bond is formed when monosaccharides join together?
Glycosidic bond
32
Describe the structure of cellulose.
Cellulose is made of long, straight chains of β-glucose joined by glycosidic bonds.
33
How does the structure of starch differ from cellulose?
Starch is coiled or branched, while cellulose has straight unbranched chains.
34
What is the function of glycogen in animals?
Glycogen serves as an energy store in animals.
35
How does the branching of glycogen benefit its function?
The branching allows for quick release of glucose for respiration.
36
What are the roles of lipids?
* Long-term energy store
* Insulation
* Waxy layer to reduce water loss
* Produce metabolic water when respired
* Protection of organs
* Structural component of cell membranes
## Footnote
Roles of lipids include energy storage, insulation, and providing structure to cell membranes.
37
What are the components of triglycerides?
* Glycerol
* 3 fatty acids
## Footnote
Triglycerides are formed by the combination of glycerol and three fatty acids.
38
How are triglycerides formed?
Glycerol + 3 fatty acids → triglyceride + 3 water molecules
## Footnote
The formation of triglycerides involves an esterification reaction where water is released.
39
What defines saturated and unsaturated fatty acids?
* Saturated: no carbon-carbon double bonds
* Unsaturated: one or more carbon-carbon double bonds
## Footnote
Saturated fatty acids typically come from animal sources, while unsaturated fatty acids mainly come from plant sources.
40
What is the structure of phospholipids?
* Glycerol
* 2 fatty acids
* Phosphate group
## Footnote
Phospholipids have hydrophilic heads and hydrophobic tails, leading to the formation of bilayers in water.
41
What is the process to test for lipids?
Dissolve in ethanol, then add water and mix. A white emulsion indicates lipid presence.
## Footnote
This test highlights the solubility of lipids in alcohol and their insolubility in water.
42
Fill in the blank: Fats and oils make up a group of lipids called ___________.
triglycerides
## Footnote
Triglycerides are the main form of lipids found in the body.
43
Fill in the blank: A fatty acid with carbon-carbon double bonds is called _______________.
(poly)unsaturated
## Footnote
These fatty acids are typically liquid at room temperature.
44
Fill in the blank: In a phospholipid, there are ___ fatty acids.
2
## Footnote
The presence of two fatty acids is key to the amphipathic nature of phospholipids.
45
Fill in the blank: Fatty acids are described as ___________ because they repel water.
hydrophobic
## Footnote
This property is crucial for the formation of cell membranes.
46
What are the four levels of protein structure?
* Primary
* Secondary
* Tertiary
* Quaternary
## Footnote
Each level of protein structure contributes to the overall shape and function of the protein.
47
What is primary structure in proteins?
The specific sequence of amino acids in the polypeptide chain.
## Footnote
The primary structure determines all other levels of protein structure.
48
What bonds are present in the secondary structure of proteins?
Hydrogen bonds
## Footnote
These bonds stabilize the alpha-helix and beta-pleated sheet formations.
49
What bonds are present in the tertiary structure of proteins?
* Hydrogen bonds
* Ionic bonds
* Disulfide bridges
## Footnote
Tertiary structure refers to the overall 3D shape of a protein, influenced by various types of bonding.
50
How do amino acids join together?
Through peptide bonds formed during condensation reactions.
## Footnote
Peptide bonds are formed between the amino group of one amino acid and the carboxylic acid group of another.
51
What is the Biuret test for proteins?
No protein → sample remains blue; Protein present → purple/lilac/mauve color.
## Footnote
This test is used to detect the presence of proteins in a sample.
52
What causes denaturation of proteins?
* Temperature
* pH
* Salt concentration
* Heavy metals
## Footnote
Denaturation disrupts the protein's structure, leading to loss of function.
53
What are fibrous proteins?
* Collagen
* Keratin
* Silk
## Footnote
Fibrous proteins are typically structural and insoluble in water.
54
What are globular proteins?
* Enzymes (e.g., amylase, lipase)
* Hormones (e.g., insulin, estrogen)
* Transport proteins (e.g., hemoglobin)
## Footnote
Globular proteins are usually soluble in water and have various functions including catalysis and transport.
55
How many different tripeptides can be made with 20 amino acids?
20^3 = 8,000
## Footnote
This is calculated based on the combination of three amino acids chosen from 20 options.
56
57
What are enzymes?
Biological catalysts that lower activation energy and facilitate biochemical reactions.
58
What is the structure of enzymes?
Globular proteins with a specific tertiary structure.
59
What types of reactions can enzymes catalyse?
* Anabolic ('builder') reactions
* Catabolic ('breaker') reactions
60
What is the active site of an enzyme?
A small hollow depression made up of a small number of amino acids.
61
What does enzyme specificity refer to?
Enzymes are specific to a single substrate or a specific bond.
62
What are the two models of enzyme action?
* Lock & Key Model
* Induced Fit Model
63
Describe the Lock & Key Model.
Temporary bonds are formed between amino acids and the substrate molecule.
64
Describe the Induced Fit Model.
The active site is slightly flexible and changes shape upon substrate interaction.
65
What effect do enzymes have on activation energy?
Enzymes always lower the activation energy.
66
What is the temperature coefficient Q10?
Measures the rate of change of a reaction when the temperature is increased by 10 °C.
67
What is the typical Q10 value for many enzymes?
Approximately 2, meaning the rate of reaction doubles with a 10 °C increase.
68
What factors affect enzyme activity?
* Substrate concentration
* Enzyme concentration
* Temperature
* pH
69
What happens when an enzyme is denatured?
Hydrogen and ionic bonds are broken, leading to loss of tertiary structure and altered active site shape.
70
What is an enzyme inhibitor?
Substances that interfere with enzyme activity.
71
What are the two types of enzyme inhibitors?
* Competitive inhibitors
* Non-competitive inhibitors
72
How do competitive inhibitors work?
They compete with the substrate for the active site, decreasing E-S complexes formed.
73
How do non-competitive inhibitors work?
They bind away from the active site, altering the enzyme's tertiary structure and reducing E-S complexes.
74
What is ATP?
Adenosine triphosphate, the universal energy carrier in cells.
75
How is energy released from ATP?
Through hydrolysis, releasing energy in small amounts.
76
What is the ATP cycle?
* ATP hydrolysis releases energy
* ADP and Pi undergo condensation to resynthesize ATP
77
What is the daily ATP turnover in human cells?
100 to 150 moles of ATP daily, equating to around 50 to 75 kg.
78
Fill in the blank: Enzymes are soluble in water due to many _______ side groups on their amino acids.
hydrophilic
79
True or False: Enzymes can catalyse reactions without lowering the activation energy.
False
80
What role does ATP play in cellular processes?
ATP is used for all cellular processes requiring energy.
81
What is the significance of stepwise oxidation in respiration?
Allows energy to be captured as ATP rather than released as heat.
82
83
Why is DNA important?
DNA is important because it codes for polypeptides, determines inherited characteristics, provides genetic diversity, and has the ability to self-replicate.
84
What do genes code for?
Genes code for polypeptides.
85
What is the role of DNA mutations?
DNA mutations provide genetic diversity.
86
How does DNA replicate?
DNA replicates through complementary base pairing, essential for cell division.
87
What is the structure of DNA?
DNA has a double helix structure made of two polynucleotide chains.
88
Define a chromosome.
A chromosome is a structure that organizes DNA in eukaryotes.
89
What is a gene?
A gene is a section of a chromosome that codes for a particular protein.
90
How many pairs of chromosomes are in the human nucleus?
The human nucleus contains 23 pairs of chromosomes.
91
What are the components of a nucleotide?
A nucleotide is made up of a sugar, phosphate, and a base.
92
What is the sugar present in DNA?
The sugar present in DNA is deoxyribose.
93
List the four bases in DNA.
* Adenine
* Thymine
* Guanine
* Cytosine
94
What type of bond forms the sugar-phosphate backbone of DNA?
Phosphodiester bonds form the sugar-phosphate backbone.
95
How do complementary base pairs bond in DNA?
Adenine pairs with Thymine, and Cytosine pairs with Guanine through hydrogen bonds.
96
Describe the double helix structure of DNA.
The double helix consists of two polynucleotide chains twisted around each other.
97
What is the difference between DNA and RNA?
DNA contains thymine, while RNA contains uracil; DNA is double-stranded, RNA is single-stranded.
98
Where is DNA found in eukaryotic cells?
DNA is found inside the nucleus of eukaryotic cells.
99
What is the function of mRNA?
mRNA transfers genetic information from DNA to ribosomes for translation.
100
What is the shape of tRNA?
tRNA has a clover-leaf shape.
101
What are codons?
Codons are triplets of bases in mRNA that correspond to amino acids.
102
Fill in the blank: DNA is a large complex molecule made up of many sub-units called _______.
nucleotides
103
True or False: Adenine always pairs with Thymine in DNA.
True
104
True or False: DNA is a single-stranded molecule.
False
105
What is semi-conservative DNA replication?
Semi-conservative replication means each new DNA molecule consists of one old strand and one new strand.
106
What enzyme breaks hydrogen bonds during DNA replication?
DNA helicase breaks hydrogen bonds.
107
What role does DNA polymerase play in DNA replication?
DNA polymerase joins new nucleotides together into a polynucleotide chain.
108
List the three hypotheses for DNA replication.
* Conservative
* Dispersive
* Semi-conservative
109
What is the main purpose of DNA replication?
The main purpose of DNA replication is to ensure that daughter cells receive the correct number of chromosomes.
110
What is the significance of the order of bases in DNA?
The order of bases determines an organism's characteristics.
111
What are the two main types of RNA involved in protein synthesis?
* mRNA
* tRNA
112
113
What type of bonds contribute to the folding and twisting of proteins?
Hydrogen, ionic and disulphide bonds
114
What is the specific sequence of amino acids in a protein called?
Polypeptide chain
115
What structures can a polypeptide chain fold into due to hydrogen bonding?
Alpha helices and beta pleated sheets
116
What is the formula of water?
H2O
117
What type of bonds hold the hydrogen and oxygen atoms together in a water molecule?
Covalent bonds
118
What is the distribution of charge in a water molecule?
Polar (uneven distribution of charge)
119
Which atom in water is slightly negative?
Oxygen
120
What effect does the hydrogen bonding in water have on its surface tension?
High surface tension
121
What phenomenon occurs when water forms a 'dome' shape on a penny?
Surface tension
122
True or False: Cohesion in water is caused by hydrogen bonds.
True
123
What is the role of water's large latent heat of vaporization?
Temperature regulation
124
How does sweating help in temperature regulation?
Heat energy is removed from the body to evaporate sweat
125
What role do strong cohesive forces in water play in plants?
Maintains water columns in xylem
126
What type of skeleton do earthworms possess?
Hydrostatic skeleton
127
What is the main function of inorganic ions in organisms?
Various roles including structural components and enzyme activity
128
What is the role of sodium ions in cells?
Co-transport of glucose and amino acids across cell membranes
129
What is the function of iron in the body?
Component of hemoglobin which transports oxygen
130
What is the role of hydrogen ions in biological systems?
Determining pH and affecting protein structure and enzyme activity
131
What is the importance of phosphate ions?
Structural component of DNA, RNA and ATP
132
What is the equation for aerobic respiration?
C6H12O6 + 6O2 → 6H2O + 6CO2 + energy
133
What is ATP?
Adenosine triphosphate, the universal energy carrier
134
How is energy released from ATP?
Hydrolysis
135
What happens during ATP resynthesis?
Condensation of ADP and inorganic phosphate
136
Fill in the blank: The total quantity of ATP in the human body is about _______.
0.1 mole
137
How much ATP do human cells hydrolyze daily?
100 to 150 moles
138
What is one use of ATP in cellular processes?
Synthesis and cellular work
139
True or False: Energy stored in starch and glycogen is readily accessible.
False
