The process that introduces new genetic variation into a population is: MCQ with Answer and Explanation

The process that introduces new genetic variation into a population is:
A. Genetic drift
B. Natural selection
C. Mutation
D. Gene flow
Answer: Option C
Solution (By JKExamLibrary)
Mutations are random changes in DNA sequence that create new alleles, serving as the ultimate source of genetic variation. Natural selection, genetic drift, and gene flow act on existing variation but do not create new alleles. Mutations can be beneficial, neutral, or deleterious, and are essential for evolution.

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Practice More Biology Questions

Question #1
In the human body, the 'Reticular Activating System' (RAS) is a network of neurons located in the brainstem. Its primary function is to:
A. Regulate heart rate and breathing
B. Process visual and auditory information
C. Control voluntary motor movements
D. Regulate arousal, wakefulness, and the sleep-wake transition

Correct Answer: Option D


Explanation:
The Reticular Activating System (RAS), or Ascending Reticular Activating System (ARAS), is a complex network of neurons located in the core of the brainstem (spanning the medulla, pons, and midbrain). It projects diffusely to the thalamus and cerebral cortex. Its primary function is to regulate the overall level of arousal, consciousness, and wakefulness of the brain. It filters incoming sensory information, allowing important stimuli to reach conscious awareness, and plays a crucial role in the sleep-wake cycle and transitions between sleep stages.

This question belongs to: Science Biology
Question #2
Which part of the human brain is primarily responsible for maintaining balance and posture?
A. Cerebrum
B. Medulla oblongata
C. Cerebellum
D. Hypothalamus

Correct Answer: Option C


Explanation:
The cerebellum is a highly folded structure located at the back of the brain, below the cerebrum. It is primarily responsible for coordinating voluntary movements, maintaining balance, posture, and equilibrium. Damage to the cerebellum results in ataxia (lack of muscle coordination). The medulla controls vital involuntary functions like breathing and heart rate.

This question belongs to: Science Biology
Question #3
The 'pUC19' plasmid is a widely used cloning vector. A key feature of pUC19 that facilitates the selection of recombinant clones is the presence of:
A. The rop gene for replication control
B. Genes for nitrogen fixation
C. Multiple origins of replication
D. The lacZ gene for alpha-complementation (blue-white screening)

Correct Answer: Option D


Explanation:
pUC19 is a small, high-copy-number cloning vector. A crucial feature for selecting recombinant clones is the presence of the lacZ' gene, which codes for the alpha-peptide of beta-galactosidase. The multiple cloning site (MCS) is located within this lacZ' gene. When foreign DNA is inserted into the MCS, it disrupts the lacZ' gene (insertional inactivation). On media containing X-gal and IPTG, colonies with empty vectors turn blue, while colonies with recombinant plasmids (disrupted lacZ') remain white, allowing easy visual selection.

This question belongs to: Science Biology