STD 11 - 4. Animal kingdom — NEET STD 11 Science — Question

Which statements are incorrect for mechanisms of nerve impulse conduction along electrical junctions of neuron or electrical synapse ?
(i) Nerve impulse flow directly from one neuron to other across the synapses in electrical synapses.
(ii) Transmission of an impulse across electrical synapses is very similar to impulse conduction along a single axon.
(iii) Impulse transmission across an electrical synapse is always faster than that across a chemical synapse.
(iv) Electrical synapses are rare in our system.
(v) At an electrical synapse, the membranes of the pre and post-synaptic neurons are separated by a fluid-filled space called synaptic cleft is thick.
(vi) Chemicals called neurotransmitters are involved in the transmission of impulses at this synapse.

Identify wrong pair

Animals with metameric segmentation, bilateral symmetry and closed circulatory system belong to phylum

Name a peptide hormone which acts mainly on hepatocytes, adipocytes and enhances cellular glucose uptake and utilisation.

The male sex hormone 'testosterone' is secreted by special Leydig's cells present in

The closest relative of modern day man is considered to be

Trisomic condition of Down's syndrome arises due to

Feeding in sponges takes place through

Which of the following option contain wrong statement regarding exchange of gases ?
(i) Alveoli are the primary sites of exchange of gases.
(ii) Exchange of gases also occurs between blood and tissues.
(iii) O₂ and CO₂ are exchanged mainly based on pressure/concentration gradient.
(iv) Solubility of the gases as well as the thickness of the membranes involved in diffusion are also some important factors that can affect the rate of diffusion.
(v) Solubility of CO₂ is 20-25 times lower than that of O₂.
(vi) The amount of CO₂ that can diffuse through the diffusion membrane per unit difference in partial pressure is much lower compared to that of O₂

In an organism, pink spot is a sex-linked recessive trait and black hair is dominant to white. If a pink spotted black heterozygous female is mated to a white male which is not spotted, the phenotypic ratio of the offspring would be