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

Question 1

If a double-stranded DNA molecule contains 20% Cytosine, what is the percentage of Adenine?

Accepted Answer

30%

Answer

20%

Answer

40%

Answer

60%

Question 2

According to the Egyptian STEM biology syllabus, what is the exact scientific deduction regarding: Physiological vs. Structural Support in Plants?

Accepted Answer

Physiological support is temporary and completely dependent on water uptake into vacuoles via osmosis, while structural support is permanent via deposition of cellulose, lignin, or suberin

Answer

Physiological support involves permanent deposition of lignin in stone cells

Answer

Both physiological and structural supports disappear immediately when the plant wilts

Answer

Structural support relies solely on turgor pressure of living parenchyma

Question 3

According to the Egyptian STEM biology syllabus, what is the exact scientific deduction regarding: Sliding Filament Theory of Muscle Contraction (Huxley)?

Accepted Answer

During sarcomere contraction, actin filaments slide over myosin filaments; the I-band and H-zone shorten, while the A-band length remains strictly constant

Answer

Both A-band and myosin filaments shrink by 50% in length

Answer

Z-lines move away from each other as the muscle contracts

Answer

Cross-bridges pull actin filaments outward away from the M-line

Question 4

According to the Egyptian STEM biology syllabus, what is the exact scientific deduction regarding: Hormonal Regulation of Blood Glucose (Insulin and Glucagon)?

Accepted Answer

Beta cells of the islets of Langerhans secrete insulin to lower blood glucose by stimulating cellular uptake and glycogen synthesis, while alpha cells secrete glucagon to raise blood glucose by glycogenolysis

Answer

Alpha cells secrete insulin to elevate blood glucose levels

Answer

Insulin stimulates the breakdown of liver glycogen into glucose

Answer

Glucagon is secreted by the adrenal cortex under stress

Question 5

According to the Egyptian STEM biology syllabus, what is the exact scientific deduction regarding: Parthenogenesis in Honeybees (Apis mellifera)?

Accepted Answer

The queen honeybee produces haploid drones (males, n) from unfertilized eggs via parthenogenesis, whereas diploid worker and queen females (2n) arise from fertilized eggs

Answer

Male drones arise from fertilized diploid zygotes (2n)

Answer

Female worker bees develop parthenogenetically without fertilization

Answer

Drones produce sperm cells by meiotic division

Question 6

According to the Egyptian STEM biology syllabus, what is the exact scientific deduction regarding: Plant Immunity: Role of Tyloses and Pre-existing Barriers?

Accepted Answer

Tyloses are balloon-like protrusions of xylem parenchyma cells that grow into xylem vessels through pits to block pathogen spread following vascular damage

Answer

Tyloses are biochemical antibodies synthesized by plant ribosomes

Answer

Tyloses accelerate the flow of infected sap to the leaves

Answer

Tyloses dissolve the fungal cell wall via chitinase enzymes

Question 7

According to the Egyptian STEM biology syllabus, what is the exact scientific deduction regarding: Chargaff's Rules of DNA Base Pairing?

Accepted Answer

In any double-stranded DNA molecule, the percentage of Adenine equals Thymine (%A = %T) and Guanine equals Cytosine (%G = %C), with total purines equaling pyrimidines (%A + %G = %T + %C = 50%)

Answer

Adenine bonds with Guanine via three hydrogen bonds

Answer

The percentage of %A + %T always equals 50% in all organisms

Answer

Uracil replaces Thymine in the double helix of nuclear DNA

Question 8

According to the Egyptian STEM biology syllabus, what is the exact scientific deduction regarding: Transcription and Translation during Protein Synthesis?

Accepted Answer

RNA polymerase synthesizes mRNA from the antisense DNA template strand in the 5' to 3' direction, and translation occurs on ribosomes where tRNA anticodons bind mRNA codons

Answer

DNA polymerase transcribes mRNA in the cytoplasm

Answer

Translation begins at the UAA stop codon

Answer

tRNA molecules contain codons identical to DNA triplets

Question 9

According to the Egyptian STEM biology syllabus, what is the exact scientific deduction regarding: Geological Dating and Index Fossils?

Accepted Answer

Index fossils must exhibit a wide geographic distribution and a short, well-defined chronological stratigraphic range to accurately correlate sedimentary rock layers

Answer

Index fossils must be restricted to a single local rock formation

Answer

Index fossils lived continuously throughout all geological eras

Answer

Index fossils are formed exclusively in intrusive igneous granite

Question 10

STEM Biology Problem 1: A double-stranded DNA segment contains 1,200 nucleotides, of which 240 are Adenine. What is the total number of Cytosine bases and hydrogen bonds in this segment?

Accepted Answer

360 Cytosine bases and 1,560 total hydrogen bonds

Answer

240 Cytosine bases and 1,200 hydrogen bonds

Answer

480 Cytosine bases and 1,800 hydrogen bonds

Answer

120 Cytosine bases and 960 hydrogen bonds

Comparison

19 Comparison

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