"a tissue section is fixed to a microscope slide, then incubated with a fluorescently labeled antibody that binds to an antigen expressed by cells in that tissue. the preparation is then washed and inspected with a fluorescent microscope. this technique is called: "

The question is incomplete as it does not have the options which are:

A. direct immunofluorescence.

B. indirect immunofluorescence.

C. fluorescence polarization.

D. autofluorescence.

The correct answer will be option-A

Explanation:

Direct immunofluorescence or the primary fluorescence is a technique used in the laboratories to diagnose the disease related to kidney, skin and other organ systems.

The technique is performed by applying antibody–fluorophore conjugate molecules to the antigen expressed by the cells of the infected tissue.

When the tissue is observed with a fluorescent microscope, the fluorophore emits light of its own wavelength which help analyse the antigen and the staining pattern in the tissue.

Thus, option-A is the correct answer.

Answer/ Explanation:

During the cell cycle, the cell divides to produce daughter cells carrying the same genetic information. In order to pass on the genetic information, the DNA must be replicated. DNA replication is said to be semi-conservative, because 1 parental double stranded DNA molecule forms 2 daughter double stranded DNA molecules, each carrying a strand from the parental molecule.

Various enzymes are involved in the process of DNA replication, such as DNA helicase, and DNA polymerase. The DNA strand is unwound, and a new strand is synthesised from the template strand through a process called complementary base pairing. This means the newly synthesised strand is complementary to the original strand.

Nucleotides are added to the newly synthesised DNA strand by DNA polymerase, according to the information in the template strand. DNA polymerase has proof-reading capabilities, allowing it to recognise and fix any errors it might have made in the nucleotide sequence.