Biology Test - 19

Estradiol is secreted by graafian follicle and theca externa.

The graafian follicle is a fluid filled cavity which is present adjacent to the oocyte. It contains Granulosa and theca cells which continuously divide. It produces estrogen. The production of estrogen requires both the cells of the theca interna and granulosa cells.

The theca externa is a connective tissue layer derived from fibroblast-like cells that produce extracellular matrix factors, such as collagen. The theca interna and externa also contain a rich supply of blood vessels called the vascular tissue that brings nutrients, oxygen, and immune cells to the growing follicles.

Sclerenchyma: is a simple permanent plant tissue. It provides mechanical stiffness and strength to the plants. It is composed of dead cells i.e non-living or dead cells.

Sclerenchyma tissue, when mature, is composed of dead cells that have heavily thickened walls containing lignin and a high cellulose content (60%–80%), and serves the function of providing structural support in plants.

ELISA diagnostic technique will you recommend for detection if patient is suspected to be suffering from acquired Immunodeficiency disorders.

An enzyme-linked immunosorbent assay, also called ELISA is a test that detects and measures antibodies in your blood. This test can be used to determine if you have antibodies related to certain infectious conditions.

Azithromycinis the 6-methyl derivative of erythromycin.

Azithromycin is the derivatives of the older macrolide antibiotic erythromycin. They are used in the treatment of a variety of infections, including community-acquired respiratory tract infections and mycobacterial infections

Superoxide is most dangerous free radical.

Superoxide promotes hydroxyl-radical formation and consequent DNA damage in cells of all types. It is striking that both growth defects and DNA damage caused by superoxide ensue from its ability to damage a subset of iron–sulfur clusters.

The correct answer is : 1 - c, 2 - a, 3 - b.

Splicing: During the process of splicing, introns are removed from the pre-mRNA by the spliceosome and exons are spliced back together. Splicing occurs in the nucleus before the RNA migrates to the cytoplasm.

Capping: The capping process replaces the triphosphate group with another structure called the "cap". The cap is added by the enzyme guanyl transferase. This enzyme catalyzes the reaction between the 5' end of the RNA transcript and a guanine triphosphate (GTP) molecule.

Tailing: Tailing is an enzymatic method for adding a non-templated nucleotide to the 3' end of a blunt, double-stranded DNA molecule. Tailing is typically done to prepare a T-vector for use in TA cloning or to A-tail a PCR product produced by a high-fidelity polymerase (not Taq) for use in TA cloning.

In prokaryotes, the hair-like outgrowths which attach to the surface of other bacterial cells are calledPili.

Prokaryotic cells comprise bacteria and archaea. Their genetic material isn’t stored within a membrane-bound nucleus. Instead, it is stored in a nucleoid that floats in the cell’s cytoplasm. Prokaryotic cells are normally smaller than eukaryotic cells, with a typical size range of 0.1 to 5 μm in diameter.

Fimbriae and pili can often be found on the surface of bacterial cells. Fimbriae are short, hair-like projections that attach a bacterium to a substrate or other cells. Pili are similar structures that can serve many functions, including helping the bacterium move or helping it transfer DNA to another bacterium.

The male reproductive organs include a pair of testes (singular, testis), two sperm ducts, and a penis.

The testes produce the male gametes called sperms. Millions of sperms are produced by the testes.

Though sperms are very small in size, each has a head, a middle piece, and a tail.

The male reproductive system does not include the cervix. Cervix is a part of the female reproductive tract.

The female reproductive organs are a pair of ovaries, oviducts (fallopian tubes), Cervix, Vagina, and uterus.

Ovaries produce female gametes called ova (eggs).

In human beings, a single matured egg is released into the oviduct by one of the ovaries every month.

The uterus is the part where the development of the baby takes place. Like the sperm, an egg is also a single cell.

Cardiac muscles are involuntary, vigorous and rhythmic.

Cardiac muscles are the muscles of the heart. They are self-contracting, autonomically regulated (meaning involuntary) and must continue to contract in a rhythmic fashion for the whole life of the organism.

Light reaction occurs in the thylakoid membrane of the chloroplasts. It involves cyclic and non cyclic photophosphorylation. Photophosphorylation is the production of ATP from ADP and H3PO4 in presence of light and chlorophyll-a during the photochemical phase of photosynthesis.

During cyclic photophosphorylation, ATP is produced and in non cyclic photophosphorylation, ATP and NADPH2 are produced. Oxygen is also formed as a result of photolysis of water.

So, the products of light reaction are ATP, NADPH2 and O2.