The technique of polymerase chain reaction (PCR) is used to:
A. Cut DNA at specific sites
B. Sequence DNA
C. Separate DNA fragments by size
D. Amplify a specific DNA sequence
Answer: Option D
Solution (By JKExamLibrary)
PCR is an in vitro technique to exponentially amplify a specific DNA segment using primers, Taq polymerase, and thermal cycles. Electrophoresis separates DNA, sequencing determines base order, restriction enzymes cut DNA.
Explanation:
In botanical classification, the term 'Division' corresponds to 'Phylum' in zoological classification. For example, flowering plants are in the Division Magnoliophyta (or Angiosperms), while animals are in Phyla like Chordata. The hierarchy is Kingdom → Division/Phylum → Class → Order → Family → Genus → Species. This terminological difference is a key point in taxonomy.
Consider the following statements about the human heart:
1. The pericardium is a protective sac around the heart.
2. The endocardium lines the heart chambers.
3. The myocardium is the outermost layer.
Which of the above is/are correct?
Explanation:
Pericardium is outer sac, endocardium inner lining. Myocardium is the middle muscular layer; the outermost is epicardium (visceral pericardium). So 3 is incorrect.
Explanation:
Dendrites are branched extensions of the neuron cell body that receive synaptic inputs from other neurons and transmit graded potentials towards the soma. The axon conducts action potentials away from the soma to the terminals, which then synapse with other cells. Dendrites have receptor sites for neurotransmitters.
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