Which of the following is a correct statement about the structure of a neuron?
A. Dendrites transmit impulses away from the cell body.
B. The myelin sheath speeds up impulse conduction by allowing continuous conduction.
C. The axon receives impulses from other neurons.
D. The cell body contains the nucleus and most organelles.
Answer: Option D
Solution (By JKSSB Mock Tests)
The soma (cell body) of a neuron contains the nucleus and metabolic machinery. Dendrites receive signals from other neurons and transmit them towards the soma, while the axon carries impulses away from the soma. The myelin sheath speeds up conduction by saltatory conduction (jumping between nodes), not continuous conduction.
Consider statements about human nutrition: 1. Proteins are made of amino acids. 2. Carbohydrates are made of fatty acids. 3. Fats are made of glycerol and fatty acids. Which are correct?
Explanation:
Proteins are complex macromolecules composed of long chains of amino acids linked by peptide bonds. Fats (triglycerides) are lipids composed of one glycerol molecule esterified to three fatty acid chains. Carbohydrates are composed of simple sugars (monosaccharides) like glucose, not fatty acids. Thus, statements 1 and 3 are correct, while statement 2 is false.
Explanation:
Reptiles generally have a three-chambered heart with two atria and one partially divided ventricle; crocodiles are an exception with a four-chambered heart. Amphibians have a three-chambered heart with two atria and one undivided ventricle. Mammals and birds have four-chambered hearts. This adaptation reflects their metabolic demands and evolutionary advancement.
Explanation:
Carrot and radish are examples of modified taproots where the primary root swells to store food. Prop roots are adventitious (banyan), fibrous roots are fine and branching (grasses), adventitious arise from stems/leaves.
No comments yet. Be the first to start the discussion!