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Biology & Geology

Chapter 1 - Support and Movement in Living Organisms

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Chapter 2 - Hormonal Coordination in Living Organisms

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Chapter 3 - Reproduction in Living Organisms

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Chapter 4 - Immunity in Living Organisms

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Chapter 5 - Molecular Biology - DNA Structure and Function

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Chapter 6 - Molecular Biology - RNA, Protein Synthesis and Genetic Engineering

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Chapter 7 - Geology, Earth Sciences and Ecology

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Quiz

Lesson 2 Quiz: DNA Structure, Replication and DNA Repair Enzymes

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  • Questions count: 20
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1.
Which of the following organisms has its genetic material as a single molecule of RNA rather than DNA?
Yeast
Escherichia coli bacteria
Human immunodeficiency virus (HIV), polio virus, influenza and coronavirus
Bacteriophage T2
2.
A mercury manometer connected to a gas tank shows the mercury level in the free arm is 4 cm higher than the gas arm (Pa = 76 cm Hg). The gas pressure is:
72 cm Hg
80 cm Hg
76 cm Hg
4 cm Hg
3.
The atom in the pentose sugar molecule (dioxyribose) to which the nitrogenous base is linked by a covalent bond is:
Carbon atom number 3'
Carbon atom number 2'
Carbon atom number 1' (C1')
Carbon atom number 5'
4.
The polyadenyne tail (Poly-A Tail) added to the end of the mRNA molecule in eukaryotes consists of about 200 adenine nucleotides and functionally functions to:
Encoding polar amino acids
Formation of the nuclear envelope
Binding to the polymerase enzyme
Protecting the mRNA molecule from degradation by enzymes in the cytoplasm
5.
The covalent chemical bond that connects the heavy and light peptide chains in an antibody molecule is:
Weak hydrogen bonds
Ionic bonds
Additional peptide bonds
Disulfide Bonds - S-S
6.
The nitrogen molecule (N2) contains a:
Coordinate dative bond
Triple covalent bond (one sigma bond and two pi bonds) sharing 3 electron pairs
Single ionic bond
Double covalent bond
7.
Substances secreted by T helper cells (Th) and acting as a communication tool to activate neighboring B and T cells are:
Hemoglobin
Myoglobin
Interleukins
Antibodies
8.
Which of the following compounds exhibits polar covalent bonding due to a significant difference in electronegativity between 0.4 and 1.7?
Sodium chloride (NaCl)
Chlorine gas (Cl2)
Methane (CH4)
Water (H2O)
9.
Injection with serum (Antiserum) containing ready-made antibodies to neutralize scorpion venom gives the patient immunity:
Lasting positivity
Innate
Cellular induced
A rapid and temporary acquired negativity that is not accompanied by memory cells
10.
The two sites on the subunit of the ribosomal subunit where the two tRNA molecules stabilize during polypeptide chain elongation are:
The location of the palace and the location of the IUD
Coiling site and binding site
Peptidyl site (P) and aminoacyl site (A)
Location 5' And site 3'
11.
If a double-stranded DNA sample contains 28% Adenine, what is the exact percentage of Cytosine in this sample?
22%
56%
28%
44%
12.
The sum to infinity (S_infinity) of a geometric series exists and converges if and only if the common ratio satisfies:
|r| >= 2
|r| < 1 (i.e. -1 < r < 1), and S_infinity = a / (1 - r)
r > 1
r = 1
13.
According to the 2026/2027 Egyptian STEM biology syllabus, what is the exact scientific deduction regarding: Chargaff's Rules of DNA Base Pairing?
In any double-stranded DNA molecule, the percentage of Adenine equals Thymine (%A = %T) and Guanine equals Cytosine (%G = %C), with purines equaling pyrimidines
The percentage of %A + %T always equals 50% in all organisms
Uracil replaces Thymine in the double helix of nuclear DNA
Adenine bonds with Guanine via three hydrogen bonds
14.
A gas cylinder contains 10 liters of gas at a pressure of 3.0 atm. If the volume is reduced to 2.5 liters at constant temperature, the new pressure inside the cylinder will be:
7.5 atm
12.0 atm
6.0 atm
1.2 atm
15.
The hormone that is secreted from the stomach lining and travels through the blood to return to the same stomach, stimulating it to secrete its digestive gastric juices, is:
Gastrin hormone
Secretin hormone
Cholecystokinin hormone
Pepsin hormone
16.
The hydrostatic pressure exerted by a static homogeneous liquid of density rho at depth h beneath its free surface is expressed by:
P = 1/2 rho * g * h2
P = rho * g / h
P = rho * g * h
P = rho * h / g
17.
What is the direct physiological effect of injecting a healthy person with an excessive dose of the hormone insulin?
A severe drop in blood glucose levels (hypoglycemia) and hypoglycemic coma
Uric acid accumulation
A sharp increase in blood sugar
Increased urine secretion
18.
According to the Chain Rule, if y = (3 x2 - 5)4, then dy/dx is:
24 x (3 x2 - 5)3
12 x (3 x2 - 5)4
6 x (3 x2 - 5)3
4 (3 x2 - 5)3
19.
Charles's Law establishes that at constant pressure, the volume of a given mass of gas is directly proportional to its:
Square of the absolute temperature
Atmospheric density
Absolute temperature in Kelvin (T_K = t_C + 273.15)
Celsius temperature only
20.
The common ratio r of the geometric sequence (64, 32, 16, 8, ...) is:
r = 2
r = -1/2
r = 4
r = 1/2
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