Biology Test - 24

In photosynthetic carbon fixation, magnesium ion (Mg²⁺) is an activator for both ribulose bisphosphate carboxylase/oxygenase and phosphoenolpyruvate carboxylase enzymes. The magnesium ions help to maintain the pH and helps in the activation of enzymes.

Adrenaline hormone does not belong to the reproductive system.

Adrenaline:

This hormone is secreted by the adrenal glands in the centre of the medulla. The main function of adrenaline is to produce contraction of the spleen so as to store the blood, increase heartbeat and sweating, reduce the blood clotting period, and pupillary dilation.

Progesterone hormone:

Progesterone is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called progestogens and is the major progestogen in the body.

Estrogenhormone:

Estrogen, or oestrogen, is a category of sex hormones responsible for the development and regulation of the female reproductive system and secondary sex characteristics.

Testosteronehormone:

Testosterone is the primary sex hormone and an anabolic steroid in males. In male humans, testosterone plays a key role in the development of male reproductive tissues such as the testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair.

The cell wall is thicker in Gram +ve.

Gram +ve bacteria are bacteria with thick cell walls. In a Gram stain test, these organisms yield a positive result. The test, which involves a chemical dye, stains the bacterium's cell wall purple. Gram -ve bacteria, on the other hand, don't hold the dye.

A. Apogamy - It is the formation of sporophyte directly from a gametophyte without the formation of gametes.

B. Apospory - It is the formation of gametophyte directly from a sporophyte without the formation of spores. 

C. Recurrent agamospermy - It is the formation of an embryo sac directly from a nucellus cell or diploid megaspore mother cell.

Meristematic cells are not characterized by intercellular spaces.

Meristematic cells are at the state of continuous division. The cells are compact in the structure without any intercellular division. Furthermore, the cells are small and protoplasm fills the cell completely. The vacuoles are extremely small. The cytoplasm does not contain differentiated plastids, although they are present in rudimentary form. Meristematic cells are packed closely together without intercellular cavities. The cell wall is a very thin primary cell wall.

Chloroplasts are green plastids which function as the site photosynthesis in eukaryotic photoautotrophs. Inside the leaves, the chloroplasts occur mostly in the mesophyll cells along their walls for easy diffusion of gases and receiving optimum quantity of incident light  A chloroplast is covered by an envelope of two membranes, each of 9-10 nm thickness. Within the chloroplast, there is the membranous system consisting of grana, the stroma lamellae and the fluid stroma. This membrane system is responsible for trapping the light energy and also for the synthesis of ATP and NADPH.

So, the correct answer is 'Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion'.

(1) Stratification :- Structural component of ecosystem
(2) Aerenchyma :- Feature of hydrophytes
(3) Age pyramid :- Food chain
(4) Parthenium hysterophorus :- Exotic species donot that allow the growth of other plants near it.

Confer stability in proteins is the function of Glycosylation.

Glycosylation is a critical function of the biosynthetic-secretory pathway in the endoplasmic reticulum (ER) and Golgi apparatus. Glycosylation is a commonly conserved process in the post translational protein modifications of eukaryotes and bacteria. However, glycosylation can be introduced by chemical modification in which carbohydrate molecule is conjugated to a protein, peptide, lipids etc.

Pollen grains are generally spherical (Shapes may vary) structures measuring about 25-50 micrometers in diameter.

Pollen grains have two prominent walls, the outer exine made up of sporopollenin which is referred to as one of the most resistant organic materials known.

The inner intine layer is made of cellulose and pectin.

The cytoplasm of pollen grains is surrounded by a plasma membrane.

• The floral part that produces Pollen Grain is Anther.
• The pollen grains represent the male gametophytes. 
• Pollination is the transfer of Pollen Grains from a Male part called (Anther) of a plant to a Female part called (Stigma) of a plant.
• Types of pollination

Simple epitheliumconsists of a single layer of cells.

Epithelial tissues are type main body tissues, they are present at lining of internal cavities and surfaces of structures in the body.Epithelial tissues are involved in secretion, selective absorption, protection, transcellular transport and detection of sensation.Simple epithelium is made up of a single layer of cells and is found in the lining of blood vessels, alveoli of the lung, etc.