Answer:
Schwann cells or neurilemma cells are the cells which form the myelin sheath around neuronal axons in the peripheral nervous system (PNS) only.
Neurilemma is the collective term used for cytoplasm and nuclei present around the myelin sheath which helps in the regeneration process of nerves.
A Schwann cell surrounds the axon, invaginate it and the plasmalemma of the Schwann cells joins and from a double membrane structure called mesaxon. This mesaxon starts wrapping the axon in spiral fashion and cytoplasm start condensing into the compact myelin sheath.
Answer:
A
Explanation:
Because there are two DNA strands in the DNA molecule and they both rotate around each other in a helix formation. So two helixes = double helix.
Answer: c) amino acid
Explanation: A codon is an mRNA sequence which contains three nucleotides that codes for a particular amino acid. The codons on the mRNA are read by the ribosome during translation and the amino acid coded for by each codon is used to make a protein. There are 64 different codons in existence, each amino acid is coded for by at least one codon. Some amino acids have more than one codon. For example, the amino acid Leucine is coded for by six codons: UUA, UUG, CUU, CUC, CUA and CUG while the amino acid phenylalanine is coded for by two codons: UUU and UUC.
Answer:
an interacting group of various species in a common location
Explanation:
