Answer:
a. Developing cells may express different parts of their identical genetic instructions.
Explanation:
Humans are multicellular organisms i.e. we possess many cells in our body. These cells increase as a result of division. Although all of the cells of humans develop from one fertilized egg (zygote), the human is born with many different types of cells because of a process called CELL DIFFERENTIATION.
Cell differentiation is a process in multicellular organisms where a cell becomes more specialized in function as it divides. The set of genes contained in each cell are not expressed simultaneously i.e. some genes are expressed while others are repressed. This is how cells with the same gene possess different functions. Therefore, according to this question, developing cells may express different parts of their identical genetic instructions to be of different types.
A) Each DNA nucleotide is made up of a sugar, a phosphate group ... Adenine and thymine are connected by two hydrogen bonds, and cytosine and guanine are ... In the case of RNA, the five-carbon sugar is ribose. DNA is made up of two strands that are twisted around each other to form a right-handed helix, called a double helix. Base-pairing takes place between a purine and pyrimidine: namely, A pairs with T, and G pairs with C. In other words, adenine and thymine are complementary base pairs, and cytosine and guanine are also complementary base pairs. This is the basis for Chargaff’s rule; because of their complementarity, there is as much adenine as thymine in a DNA molecule and as much guanine as cytosine. Adenine and thymine are connected by two hydrogen bonds, and cytosine and guanine are connected by three hydrogen bonds. The two strands are anti-parallel in nature; that is, one strand will have the 3′ carbon of the sugar in the “upward” position, whereas the other strand will have the 5′ carbon in the upward position. The diameter of the DNA double helix is uniform throughout because a purine (two rings) always pairs with a pyrimidine (one ring) and their combined lengths are always equal.
Ans.
Meiosis involves a type of cell division in sexually reproducing organisms that results in formation of four daughter cells from a single parent cell, having half of the genetic material as in parent cell. Meiosis is divided into meiosis I and meiosis II.
In gamete forming cells of humans are diploid cells and have 23 pairs of chromosomes (or 46 chromosomes). Each gamete forming mother cell undergoes meiotic division to form haploid daughter cells or gametes, each with 23 chromosomes.
Thus, the correct answer is 'twenty-three' as there are 23 chromosomes present in human sex cells at the end of meiosis II.
Only one substrate level
phosphorylation occurs in the citric acid cycle (otherwise called kreb’s cycle).
This substrate level phosphorylation is catalyzed by the enzyme, Succinyl CoA Synthetase.
The substrates of this substrate level phosphorylation are Succinyl CoA, guanosine
diphosphate (GDP) and inorganic phosphate (Pi)
