a test تقييمي: Lesson 1: Types of RNA, Genetic Code and Protein Translation

Question 1

The stop codons that signal termination of translation on an mRNA molecule include:

Accepted Answer

UAA, UAG, UGA

Answer

AUG, UAA, UGA

Answer

UAC, UGG, UAA

Answer

GUA, CAU, UAG

Question 2

Which of the following cellular changes occurs directly when a wilted plant shoot is irrigated with fresh water?

Accepted Answer

Cell sap osmotic pressure increases and cell wall shrinks inward.

Answer

Water enters the vacuole via osmosis, expanding turgor pressure against the cell wall.

Answer

Lignin is immediately deposited inside the xylem vessel walls.

Answer

Cuticle thickness over leaf epidermis doubles within minutes.

Question 3

During maximal skeletal muscle contraction according to Huxley's sliding filament model, which region experiences NO change in its absolute length?

Accepted Answer

The I-band (light isotropic zone)

Answer

The H-zone (central semi-light region)

Answer

The distance between two successive Z-lines

Answer

The A-band (dark anisotropic zone)

Question 4

What is the biochemical cause of continuous, non-relaxing muscle spasm that can cause muscular tearing?

Accepted Answer

Abrupt accumulation of excessive calcium ions in the synaptic cleft.

Answer

Complete depletion of cellular ATP molecules, preventing cross-bridge detachment.

Answer

Excessive breakdown of acetylcholine by the enzyme acetylcholinesterase.

Answer

Sudden accumulation of glucose inside glycogen granules.

Question 5

How many cervical vertebrae are present in the adult human vertebral column?

Accepted Answer

5 vertebrae

Answer

7 vertebrae

Answer

12 vertebrae

Answer

4 vertebrae

Question 6

If a double-stranded DNA sample contains 28% Adenine, what is the exact percentage of Cytosine in this sample?

Accepted Answer

28%

Answer

22%

Answer

44%

Answer

56%

Question 7

Which enzyme is responsible for linking Okazaki fragments into a continuous strand during lagging strand replication?

Accepted Answer

DNA Helicase

Answer

DNA Polymerase

Answer

DNA Ligase

Answer

Reverse Transcriptase

Question 8

What is the structural characteristic of a restriction endonuclease recognition site?

Accepted Answer

It consists of 15-20 repetitive nucleotides.

Answer

It is a palindromic sequence reading identical 5' to 3' on both strands.

Answer

It contains only adenine and thymine bases.

Answer

It always begins with the start codon AUG.

Question 9

Why is the genetic code described as 'degenerate' or 'redundant'?

Accepted Answer

One codon can code for multiple different amino acids.

Answer

Multiple different codons can code for the same single amino acid.

Answer

The genetic code decays as the cell ages.

Answer

The genetic code differs completely between bacteria and humans.

Question 10

Which of the following first-row transition metal ions exhibits the highest theoretical magnetic moment in its ground state?

Accepted Answer

Fe3+ ([Ar] 3d5 with 5 unpaired electrons)

Answer

Cr3+ ([Ar] 3d3 with 3 unpaired electrons)

Answer

Cu2+ ([Ar] 3d9 with 1 unpaired electron)

Answer

Zn2+ ([Ar] 3d10 with 0 unpaired electrons)

Comparison

09 Comparison

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