Question

QUESTION 41 Indicate the order of the following things from smallest (small number) to largest (large number). Note that part marks are possible. This is a prokaryotic situation - 16S rRNA - bound ribosome - initiator tRNA - ribosomal small subunit QUESTION 42 Indicate the order of the following events from earliest first to latestas. Note that part marks are possible. Consider the prokaryotic chromosome - DNA polymerase replicates the chromosome Replication forks from merge Origin of replication melts apart - The cell divides

Answer 1

Answer41 :

Order from smallest to largest in Prokaryotic situation:

Options a-1 , b-4, c-2, d-3

a. 16srRNA – It is the component of the small subunit i.e. 30s subunit. The genes that codes for it are used generally in the process of creating phylogenies that help in the process of evolution.

b. Bound ribosome- It is found attached with surfaces of cytoplasm i.e. plasma membrane. It makes proteins that are delivered outside for secretions like insulin.

c. Initiator tRNA – The initiator tRNA (carrying fMet i.e. aminoacylated by methionyl tRNA synthetase), binds with the small ribosomal subunit and it has a complementary base pairing.

d. Ribosomal small subunit- Ribosomes are known to consists of two subunits, they are large and small. The large subunit helps in joining amino acids and prepares the polypeptide chain while a small subunit reads the sequences present on mRNA. The small subunit binds has its function to recognize and binds with the Shine-Dalgarno sequence.

Answer 42:

Options C (1), B (2), A (3), D (4).

The Prokaryotic chromosome events (in brief) are listed below:

Firstly, the Prokaryotic chromosome replication is a three-step process i.e. initiation, elongation, and termination.

1. During initiation: the assembly of initiator proteins takes place at the OriC site. this ensures that the process occurs only one time in each cycle.
2. The nucleic acid starts unwinding at the OriC site. Helicase starts opening the replication forks in both directions. Providing it for the replication process via polymerases. The origin or initiation site must be melted for helicase to work forward that surrounds to single DNA strand. (Origin of replication melts apart)
3. SSS binding proteins help preventing the rewinding of replication forks (replication forks from merge). Topoisomerase also helps in maintaining the stability and prevents coiling and relieve tension.
4. RNA primers are formed that is formed by the primase enzyme and these primers that are complementary nucleic acids to the template
5. DNA strands stars or initiates the replication process. After this, DNA polymerase III begins the addition of nucleotides that starts from the 3’ OH site of the primer. (DNA replicates the chromosome)
6. The DNA strands are all synthesized in short stretches only. And are called the Okazaki fragments.
7. Elongation continues on both strands (the lagging and the leading strand).
8. Lastly, the primers and removed and gaps present on the strands are filled up with the help of an enzyme called DNA pol I.
9. Finally, all the gaps present between the Okazaki fragments are sealed via ligase.

After all these steps, the formed chromosomes that are circular in nature (in the case of prokaryotes) sometimes remain interlinked but can be successfully resolved and every formed cell only inherits single completely formed chromosome during the process of cell division (the cell divides).