Answer:
Infectious dose refers to the minimum number or amount of pathogens required in order to produce a disease or its symptoms. In the given case, the bacterium is non-resistant and is treated with antibiotics.
The antibiotics help in neutralizing the infectious agents; however, full course should be done to eliminate the infectious agent completely out of the body.
If the course is left in between then, there are very high chances that some bacteria may survive. They might not produce disease or symptoms as they would be less than infectious dose.
However, with time, the survived bacteria gain more and more mutations during replication which can develop antibiotic resistance capability in them.
In addition, it is also possible that the survived bacteria can get R-plasmid (which has antibiotic resistant gene) from body's normal flora or from any other infectious agent present in the body by the process of transformation or conjugation.
The R-plasmid enables them to survive even in the presence of antibiotics due to which the treatment of the disease might become difficult.
Answer:
DNA ligase
Explanation:
DNA replication is a process whereby a particular DNA makes a copy of or synthesizes itself. It consists of several steps with some important enzymes for successful, error free replication. The various steps are as follows;
- Unwinding of the double helix structure of the DNA and formation of replication fork. The enzyme involved here is the DNA helicase.
- Primer, a short piece of RNA becomes synthesized and binds to the 3' end of one of the 2 strands of the DNA, the leading strand. The enzyme involved is the DNA primase.
- Replication of the <em>leading strand</em> then proceeds with the elongation of the primer through the addition of bases in the 5' to 3' direction leading to the formation of continuous strands.
- The other strand of the DNA, known as the <em>lagging strand </em>starts its own replication by binding with multiple primers at different regions of the strand. Bases are then added to each primer leading to the formation of several, short discontinuous DNA strands known as Okazaki fragments. The enzyme involved in the elongation process is the DNA polymerase.
- Next is the termination of the replication process after the formation of the continuous and discontinuous strands. Exonuclease enzyme removes primers from the synthesized strands. Primers are replaced by appropriate DNA bases and the Okazaki fragments are joined to form a unified DNA strand by an enzyme known as the DNA ligase.
The many, few nucleotides long DNA segments observed by the Biochemist are the Okazaki fragments that should have been joined together by the DNA ligase.
Hence, DNA ligase must have been the component left of the mixture.
Answer:
The biosphere is a global ecosystem composed of living organisms (biota) and the abiotic (nonliving) factors from which they derive energy and nutrients. Earth's environmental spheres. Earth's environment includes the atmosphere, the hydrosphere, the lithosphere, and the biosphere.
Explanation:
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I believe it’s A……………………..
