biological molecules Flashcards
(133 cards)
1
Q
A
2
Q
What are monomers?
A
Monomers are individual molecules that make up a polymer.
3
Q
What are polymers?
A
Polymers consist of many monomers chemically bonded together.
4
Q
What is a condensation reaction?
A
A condensation reaction removes a molecule of water from two monomers, forming a chemical bond between them.
5
Q
What is a hydrolysis reaction?
A
A hydrolysis reaction inserts a molecule of water to break the bonds between two monomers.
6
Q
What are the three types of carbohydrates?
A
Monosaccharides, Disaccharides, Polysaccharides.
7
Q
What is glucose?
A
Glucose is a hexose sugar and a monosaccharide with the formula C6H12O6.
8
Q
What are the two isomers of glucose?
A
α-Glucose and β-Glucose.
9
Q
What is a disaccharide?
A
A disaccharide is formed when two monosaccharides are joined by a condensation reaction.
10
Q
What are three common disaccharides?
A
Maltose, Sucrose, Lactose.
11
Q
What is starch?
A
Starch is a storage polysaccharide in plants, made of α-glucose.
12
Q
What is glycogen?
A
Glycogen is a storage polysaccharide in animals, also made of α-glucose.
13
Q
What is cellulose?
A
Cellulose is a structural polysaccharide made of β-glucose, providing strength to plant cell walls.
14
Q
What is the Benedict’s test used for?
A
The Benedict’s test is used to test for reducing sugars by changing color from blue to brick-red if present.
15
Q
What test is used for non-reducing sugars?
A
Hydrolyse the sample with hydrochloric acid, neutralize it, then perform the Benedict’s test.
16
Q
What is the iodine test for?
A
The iodine test is used to detect starch, changing from orange-brown to blue-black if present.
17
Q
What is a triglyceride?
A
A triglyceride consists of one molecule of glycerol and three fatty acids.
18
Q
What is a phospholipid?
A
A phospholipid consists of one glycerol, two fatty acids, and a phosphate group.
19
Q
What is the emulsion test for?
A
The emulsion test detects lipids; a milky-white emulsion indicates a positive result.
20
Q
What is an amino acid?
A
An amino acid is the monomer that forms protein polymers.
21
Q
What bond forms between amino acids?
A
A peptide bond forms between amino acids.
22
Q
What are the four structural levels of proteins?
A
Primary, Secondary, Tertiary, Quaternary.
23
Q
What is the Biuret test for?
A
The Biuret test detects proteins, changing color from blue to lilac/purple.
24
Q
What is an enzyme?
A
An enzyme is a tertiary-structured protein that speeds up reactions without being used up.
25
What is the active site of an enzyme?
The active site is the region where a substrate binds, forming an enzyme-substrate complex.
26
How do enzymes lower activation energy?
Enzymes lower activation energy by bending substrate bonds and bringing molecules together.
27
What is the lock and key theory of enzymes?
The lock and key theory states that the active site is a perfect fit for the substrate.
28
What is the induced fit theory of enzymes?
The induced fit theory suggests the active site changes shape to fit the substrate more tightly.
29
What is a competitive inhibitor?
A competitive inhibitor binds to the active site of an enzyme, blocking the substrate.
30
What is a non-competitive inhibitor?
A non-competitive inhibitor binds to a site away from the active site, altering the enzyme's shape.
31
What is DNA made of?
DNA is made of nucleotides joined by phosphodiester bonds.
32
What is the structure of DNA?
DNA is a double helix formed by two polynucleotide strands joined by hydrogen bonds between bases.
33
What are the base pairs in DNA?
Adenine pairs with Thymine, and Cytosine pairs with Guanine.
34
What is RNA?
RNA is a single-stranded polynucleotide used in protein synthesis.
35
What are the types of RNA?
The three types of RNA are mRNA, tRNA, and rRNA.
36
What is the function of mRNA?
mRNA carries the genetic code from the DNA to the ribosome for protein synthesis.
37
What is the function of tRNA?
tRNA carries specific amino acids to the ribosome for polypeptide formation.
38
What is the function of rRNA?
rRNA combines with proteins to form ribosomes, the site of protein synthesis.
39
What is the difference between DNA and RNA?
DNA is double-stranded with Thymine, while RNA is single-stranded with Uracil.
40
What is DNA replication?
DNA replication is the process of copying DNA before cell division.
41
What enzymes are involved in DNA replication?
DNA Helicase and DNA Polymerase.
42
What is semi-conservative replication?
Semi-conservative replication means each new DNA molecule contains one original strand and one new strand.
43
What is ATP?
ATP is a phosphorylated macromolecule that provides energy for cellular processes.
44
What is the function of ATP?
ATP releases energy when hydrolyzed into ADP and an inorganic phosphate.
45
What is the structure of ATP?
ATP consists of adenine, ribose, and three phosphate groups.
46
What are the properties of water that are important for life?
Water is a solvent, has high cohesion, high heat capacity, and is a metabolite.
47
What is an ion?
An ion is a charged particle that has gained or lost electrons.
48
What is the function of sodium ions (Na+)?
Sodium ions are used in the co-transport of glucose and amino acids in the small intestine.
49
What is the function of hydrogen ions (H+)?
Hydrogen ions control pH and are used in creating electrochemical gradients for ATP production.
50
What is the function of iron ions (Fe2+)?
Iron ions are a component of hemoglobin, helping transport oxygen in the blood.
51
What is the function of phosphate ions (PO4^3-)?
Phosphate ions are important in the production of ATP and nucleic acids.
52
What are the three main polysaccharides?
Starch, glycogen, and cellulose.
53
What is the function of amylose in starch?
Amylose has a helical structure making it compact for energy storage in plants.
54
What is the role of amylopectin in starch?
Amylopectin is highly branched, allowing quick hydrolysis for energy release in plants.
55
Why is glycogen highly branched?
Glycogen is highly branched to allow rapid glucose release for energy in animals.
56
What is cellulose's role in plants?
Cellulose provides structural support in plant cell walls by forming strong microfibrils.
57
What are reducing sugars?
Reducing sugars can donate electrons to reduce other molecules, detectable with Benedict’s reagent.
58
What is the principle behind the Benedict’s test?
Benedict’s reagent changes color (from blue to brick-red) in the presence of reducing sugars after heating.
59
How do you test for non-reducing sugars?
First, hydrolyze the sample with acid, neutralize it, then test with Benedict’s reagent.
60
Why are lipids not considered polymers?
Lipids are not polymers because they are not made of repeating monomer units.
61
What is a saturated fatty acid?
A saturated fatty acid contains no carbon-carbon double bonds, only single bonds.
62
What is an unsaturated fatty acid?
An unsaturated fatty acid contains at least one carbon-carbon double bond.
63
What bonds are formed in triglycerides?
Ester bonds form between the glycerol and fatty acids in triglycerides.
64
What is the significance of phospholipids in cell membranes?
Phospholipids form a bilayer with hydrophilic heads facing out and hydrophobic tails facing inward, creating a barrier.
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How do unsaturated fatty acids affect membrane fluidity?
Unsaturated fatty acids increase membrane fluidity by preventing phospholipids from packing tightly together.
66
What is a globular protein?
Globular proteins are soluble proteins with biochemical roles, such as enzymes and hormones.
67
What is a fibrous protein?
Fibrous proteins are insoluble and have structural roles, such as keratin in nails and collagen in connective tissue.
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What is the quaternary structure of proteins?
The quaternary structure is formed when two or more polypeptide chains join together.
69
What is the role of hydrogen bonds in protein structure?
Hydrogen bonds stabilize the secondary structure of proteins (alpha helices and beta sheets).
70
What is the Biuret test used for?
The Biuret test detects proteins, turning lilac/purple if proteins are present.
71
What is the difference between competitive and non-competitive inhibition?
Competitive inhibitors bind to the active site, while non-competitive inhibitors bind elsewhere, altering the enzyme's shape.
72
How do enzymes lower activation energy?
Enzymes lower activation energy by stressing substrate bonds or bringing substrates closer together.
73
What are the optimal conditions for enzyme activity?
Enzymes function best at their optimal temperature and pH, beyond which they may denature.
74
How do you calculate the rate of reaction in enzyme activity?
The rate of reaction can be calculated by measuring product formation or substrate usage over time.
75
What effect does temperature have on enzyme activity?
Increased temperature raises kinetic energy, increasing collisions, but too high temperatures cause denaturation.
76
What is the effect of pH on enzyme activity?
Deviation from the optimal pH alters ionic bonds in the enzyme, changing its active site and reducing activity.
77
How does enzyme concentration affect reaction rate?
Increasing enzyme concentration increases the rate until the substrate becomes the limiting factor.
78
What is the role of DNA Helicase in replication?
DNA Helicase unwinds the DNA double helix and breaks hydrogen bonds between bases.
79
What is the role of DNA Polymerase in replication?
DNA Polymerase joins nucleotides together to form the sugar-phosphate backbone during replication.
80
What is the semi-conservative model of DNA replication?
Semi-conservative replication means that each new DNA molecule contains one original and one new strand.
81
What did the Meselson-Stahl experiment demonstrate?
The Meselson-Stahl experiment confirmed that DNA replicates in a semi-conservative manner.
82
Why is ATP known as the universal energy currency?
ATP is used by all cells to provide energy for biological processes through hydrolysis.
83
What is the role of ATP Synthase?
ATP Synthase catalyzes the formation of ATP from ADP and inorganic phosphate during respiration.
84
How does water's high specific heat capacity benefit organisms?
Water's high specific heat capacity stabilizes temperatures in organisms and aquatic environments.
85
How does water's cohesion support life?
Cohesion allows water to form continuous columns in xylem vessels and creates surface tension for small organisms.
86
Why is water a good solvent?
Water is polar, allowing it to dissolve ions and polar molecules, facilitating transport and reactions in cells.
87
How is sodium (Na+) involved in transport across membranes?
Sodium ions are involved in co-transport of glucose and amino acids in the small intestine.
88
What is the function of hydrogen ions (H+)?
Hydrogen ions affect pH and create proton gradients for ATP production in cellular respiration.
89
What is the function of iron ions (Fe2+)?
Iron ions are a component of hemoglobin, aiding oxygen transport in the blood.
90
What is the function of phosphate ions (PO4^3-)?
Phosphate ions are essential for the formation of ATP and DNA/RNA nucleotides.
91
What is the structure of α-glucose?
In α-glucose, the hydroxyl (OH) group is below Carbon 1, and the hydrogen (H) is above Carbon 1.
92
What is the structure of β-glucose?
In β-glucose, the hydroxyl (OH) group is above Carbon 1, and the hydrogen (H) is below Carbon 1.
93
How do two α-glucose molecules form maltose?
Two α-glucose molecules undergo a condensation reaction, forming a glycosidic bond and releasing water.
94
Why is starch a good energy storage molecule?
Starch is compact (due to amylose's coiled structure) and insoluble, so it doesn’t affect water potential in cells.
95
What role does glycogen play in animal cells?
Glycogen stores glucose in animal cells, releasing it quickly for energy through its branched structure.
96
How does cellulose provide structural support?
Cellulose chains form microfibrils, which provide strength and rigidity to plant cell walls.
97
What is the function of microfibrils in cellulose?
Microfibrils formed by cellulose chains provide tensile strength in plant cell walls.
98
What happens when a polysaccharide is hydrolyzed?
The glycosidic bonds are broken, releasing monosaccharides.
99
What is the significance of hydrogen bonds in cellulose?
Hydrogen bonds between cellulose molecules strengthen plant cell walls.
100
Why can’t glucose be stored in its monosaccharide form in cells?
Glucose is soluble and would affect the water potential, causing water to enter the cell and potentially burst it.
101
What is the main difference between amylose and amylopectin?
Amylose is unbranched and coiled, while amylopectin is branched and more easily hydrolyzed.
102
What is a reducing sugar?
A reducing sugar is one that can donate electrons to another molecule, like glucose or maltose.
103
What does Benedict's reagent test for?
Benedict's reagent tests for reducing sugars; it changes color from blue to brick-red if present.
104
What is the outcome of a positive iodine test for starch?
The iodine solution turns from orange-brown to blue-black in the presence of starch.
105
Why are lipids important for energy storage?
Lipids store more energy per gram than carbohydrates and are used for long-term energy storage.
106
How do phospholipids contribute to membrane structure?
Phospholipids form a bilayer in cell membranes, with hydrophilic heads facing outward and hydrophobic tails inward.
107
Why do triglycerides provide more energy than carbohydrates?
Triglycerides contain more hydrogen-carbon bonds, which release more ATP during oxidation.
108
What is an ester bond?
An ester bond forms between the hydroxyl group of glycerol and the carboxyl group of fatty acids in lipids.
109
What is the difference between saturated and unsaturated fats?
Saturated fats have no double bonds between carbon atoms, while unsaturated fats have at least one double bond.
110
What effect does a high concentration of unsaturated fatty acids have on membrane fluidity?
Unsaturated fatty acids increase membrane fluidity by preventing tight packing of phospholipids.
111
How does a competitive inhibitor affect enzyme activity?
A competitive inhibitor competes with the substrate for the active site, reducing the rate of reaction.
112
How does a non-competitive inhibitor affect enzyme activity?
A non-competitive inhibitor binds to a site away from the active site, changing the enzyme's shape and reducing activity.
113
Why is the tertiary structure important for enzyme function?
The tertiary structure determines the shape of the active site, which is specific to the substrate.
114
How does enzyme concentration affect the rate of reaction?
Increasing enzyme concentration increases the rate of reaction until the substrate becomes the limiting factor.
115
What happens to enzyme activity at high temperatures?
At high temperatures, enzymes denature as the hydrogen bonds in the tertiary structure break, altering the active site.
116
What happens to enzyme activity at low pH?
At low pH, ionic bonds in the enzyme's tertiary structure are disrupted, changing the shape of the active site.
117
What happens during DNA replication?
DNA Helicase unwinds the double helix, and DNA Polymerase joins complementary nucleotides to the original strands.
118
What is the purpose of DNA Helicase?
DNA Helicase unwinds the DNA and breaks hydrogen bonds between bases during replication.
119
What is the purpose of DNA Polymerase?
DNA Polymerase joins adjacent nucleotides during DNA replication, forming phosphodiester bonds.
120
What is meant by complementary base pairing?
In DNA, adenine pairs with thymine and cytosine pairs with guanine through hydrogen bonds.
121
What is the role of mRNA in protein synthesis?
mRNA carries the genetic code from the DNA to the ribosome, where it is translated into a polypeptide.
122
What is the function of tRNA?
tRNA carries specific amino acids to the ribosome, where they are added to the growing polypeptide chain.
123
What is rRNA and its role?
rRNA combines with proteins to form ribosomes, the site of protein synthesis.
124
What is ATP and why is it important?
ATP is a molecule that provides energy for cellular processes through the hydrolysis of its terminal phosphate bond.
125
How is ATP synthesized?
ATP is synthesized from ADP and inorganic phosphate (Pi) by ATP Synthase during respiration or photosynthesis.
126
Why is water's high latent heat of vaporization important?
Water's high latent heat of vaporization allows organisms to cool down through sweating or transpiration without losing too much water.
127
How does water's cohesion benefit plants?
Water's cohesion allows it to be drawn up the xylem in a continuous stream, supporting transpiration.
128
How does water's high specific heat capacity support life?
Water’s high specific heat capacity buffers temperature changes, stabilizing environments for aquatic life.
129
Why is water a good solvent?
Water is polar, allowing it to dissolve ions and polar molecules, facilitating biochemical reactions.
130
What role does sodium (Na+) play in the body?
Sodium is involved in generating nerve impulses and transporting glucose and amino acids across cell membranes.
131
How do hydrogen ions (H+) affect biological systems?
Hydrogen ions determine the pH of solutions, affecting enzyme activity and other biochemical processes.
132
Why are iron ions (Fe2+) important in the body?
Iron ions are a component of hemoglobin, which binds to oxygen and transports it in the bloodstream.
133
What role do phosphate ions (PO4^3-) play in cells?
Phosphate ions are essential for ATP synthesis and the formation of DNA and RNA.
