Biology Test-11

Photosensitive receptors in plants that sense blue light are called cryptochromes.

Cryptochromes are a class of flavoproteins that are sensitive to blue light. They are found in plants and animals. Cryptochromes are involved in the circadian rhythms of plants and animals, and possibly also in the sensing of magnetic fields in a number of species.

Cell wall organelle acts as a pressure vessel.

The cell wall also acts as a pressure vessel, preventing over-expansion when water enters the cell by osmosis. The material in the cell wall varies. In plants and algae, the cell wall is made of long molecules of cellulose, pectin, and hemicellulose.

Zygote intrafallopian transfer (ZIFT) technique is used to transfer early embryo into the fallopian tube.

Zygote intrafallopian transfer (ZIFT) is an infertility treatment used when a blockage in the fallopian tubes prevents the normal binding of sperm to the egg. Egg cells are removed from a woman's ovaries, and in vitro fertilized. The resulting zygote is placed into the fallopian tube by the use of laparoscopy.

The most common substrate used in distilleries for the production of ethanol is molasses.

Molasses are used commonly in distilleries for ethanol production. Saccharomyces cerevisiae is an industrial yeast possessing most of the desirable fermentation characteristics like fast growth and fermentation rate, osmo-tolerance, high ethanol tolerance, ability to ferment molasses, and to ferment at elevated temperatures etc.

One of the very first steps of taxonomy is identification.

Taxonomy is defined as identifying and classifying different organisms into different categories. The first step of taxonomy is the identification of the organism. When we discover an organism the first step under taxonomy is identification. It is very important to identify an organism.

The mass of living material at a trophic level at a particular time is called a standing crop.

Standing crop is the total amount of living material in a specified population at a particular time, expressed as biomass (standing biomass) or its equivalent in terms of energy. The standing crop may vary at different times of the year; for example, in a population of deciduous trees between summer and winter.

\(F_{2}\) generation in a Mendelian cross showed that both genotypic and phenotypic ratio are the same as \(1: 2: 1 .\) It represents a case of Monohybrid cross with incomplete dominance.

Incomplete dominance is a type of intermediate inheritance in which one allele is not completely dominant over its paired allele. In this, the third phenotype is observed in heterozygous conditions. In monohybrid cross with incomplete dominance, the phenotypic and genotypic ratio is \(1: 2: 1\), where 1 part is with dominant phenotype, 2 parts are with intermediate phenotype and 1 part is with a recessive phenotype. For example, a snapdragon flower shows red (dominant), white (recessive), and pink (intermediate) flowers.

Anthropogenic impact implies the human impact on the environment.

The term anthropogenic designates an effect or object resulting from human activity. The term was first used in the technical sense by Russian geologist Alexey Pavlov, and it was first used in english by British ecologist Arthur Tansley in reference to human influences on climax plant communities.

The correct sequence will be- ii, vi, v, iii, i, and iv.

DNA fingerprinting involves the following steps:

i. Isolation of DNA from sample cell.

ii. If DNA is less in amount, it can be amplified using polymerase chain reaction (PCR).

iii. Digestion of this DNA by restriction endonucleases.

iv. These DNA fragments are electrophoresed in agarose gel. These fragments can be visualized by the EtBr-UV system.

v. Separated DNA fragments are transferred to nitrocellulose membrane using southern blotting.

vi. Probing for VNTRs is done using labeled DNA probes.

vii. The hybridized fragments can be detected by autoradiography.

In water-logged soil, plants do not grow properly because the soil is physiologically dry.

Physiologically dry soil means that water is present in the soil but is not available to the plants either because of high salt concentration, or lack of water in liquid form or poor aeration. These conditions respectively occur in saline marshes, cold deserts and waterlogged soil.

Four long and two short stamens are found in brassicaceae.

Brassicaceae species are characterized by four-petalled cross-shaped flowers that feature two long and two short stamens and produce podlike fruits known as siliques. Brassicaceae is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family.

Chromium is needed for insulin to exert its maximal effect in glucose uptake.

Chromium is an essential element involved in the regulation of blood glucose levels within the body. It interacts with the low-molecular-weight chromium binding substance to amplify the action of insulin. The amount of chromium in the body can be decreased as a result of a diet high in simple sugars, which increases the excretion of the metal through urine.

Middle lamella is mainly composed of calcium pectate.

The middle lamella is a layer rich in pectins which cement the cell walls of adjacent plant cells and forms plasmodesmata connections. This pectin-rich layer is made up of calcium and magnesium pectates. This layer cements the cell walls of two adjacent plant cells. It is the first formed outermost layer (cell plate formed during cell division forms the middle lamella or lamellum).

A young infant may be feeding entirely on mother's milk which is white in colour but the stools which the infant passes out are quite yellowish. The yellow colour of stool is due to undigested milk protein casein.

The yellow colour of the stools is because of the presence of bile salts. Bile colours are actually the excretory substances. The bile is a bitter-tasting, greenish-yellow in colour, an antacid fluid which is produced by the liver and temporarily stored in the gall bladder and is then discharged into the duodenum. It helps in emulsification of fats by the activity of bile salts, by decreasing the surface tension of fat droplets. These fat droplets afterwards are acted upon by lipase.

Aspergillus niger is used for the production of citric acid in industries.

The citric acid (2-hydroxy-propane-1,2,3-tricarboxylic acid) is a tricarboxylic acid that contains three carboxylic functional groups. It is a primary metabolic product formed in the tricarboxylic acid (or Krebs) cycle. Citric acid is the most important organic acid produced in tonnage and is extensively used in the food and pharmaceutical industries. It is produced mainly by submerged fermentation using Aspergillus niger or Candida sp. from different sources of carbohydrates, such as molasses and starch-based media.