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IB DP Biology- A2.3 Viruses-IB Style Questions For HL Paper 1A -New Syllabus

IBDP Biology HL Paper 1 - All Chapters

Question

What mode of existence do viruses exhibit?

(A) Obligate parasite
(B) Facultative parasite
(C) Obligate heterotroph
(D) Predator
▶️ Answer/Explanation

Correct Answer: \( \boxed{\mathbf{A}} \)

Viruses are obligate parasites because they can reproduce only inside a living host cell. They lack their own cellular machinery for metabolism and replication, so they depend entirely on the host to produce new virus particles.

Question

Which statement describes a key difference between the lytic cycle and the lysogenic cycle of bacteriophage lambda?

A.  Only in the lytic cycle is lambda DNA inserted into the host DNA.
B.  Only in the lysogenic cycle is the host metabolism used to replicate.
C.  Only in the lytic cycle is the host metabolism used to replicate.
D.  Only in the lysogenic cycle is lambda DNA inserted into the host DNA.
▶️ Answer/Explanation
In the lysogenic cycle, lambda DNA becomes integrated into the host’s chromosome, remaining dormant until triggered. This insertion does not occur in the lytic cycle.
✅ Answer: (D)

Question

What is the name for the protein shell of a virus that encloses the genetic material?

(a) Virion

(b) Capsid

(c) Peplomers

(d) Capsomers

▶️Answer/Explanation

Answer: (b)
Explanation:
The capsid is the protein shell that encloses the genetic material (DNA or RNA) of a virus.
It is made up of protein subunits called capsomers.

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