It is to grow, create, and repair the living organism
Answer:
The correct answer would be calcium ion and cAMP.
Secondary messengers refers to the intracellular signaling molecules which pass the signals from the receptors located on the surface of the cell to the target molecule present within the cell.
The secondary messengers can be classified into three major class:
- Cyclic nucleotide for example cAMP (cyclic adenosine monophosphate), cGMP (cyclic guanosine monophosphate)
- DAG (diacylglycerol) and IP₃ (inositol triphosphate)
- Calcium ions (Ca⁺⁺)
Hence, from the given options, calcium ion and cAMP would make the correct choice.
Covalent bonds share electrons between two atoms.
Answer:
The correct answer is both.
Explanation:
- Each chromosome is made up of a pair of sister chromatids which remain attached to each other at the centromere.
- During DNA replication the DNA duplicates, which means that if initially in the parent cell 'n' chromosomes were present then, after duplication, the number of chromosomes in the cell will be '2n'.
- As mentioned above, each chromosome has a pair of sister chromatids, that is, two chromatids per chromosome. So, 'n' chromosomes will have '2n' chromatids. Hence, '2n' chromosomes will have '4n' chromatids.
- In a parent cell,
- Before duplication, number of chromosome = n, number of chromatid = 2n.
- After duplication, number of chromosome = 2n, number of chromatid = 4n.
- The cell cycle proceeds as, G0, G1, S, G2, M.
- G0 represents the interphase. It occurs before replication or duplication of the chromosomes, which occurs in the S phase.
- So, in G0 phase, the chromosome number is 'n' and chromatid number is '2n'.
