Biology Test - 4

The fluid mosaic model explains various observations regarding the structure of functional cell membranes. According to this biological model, there is a lipid bilayer in which protein molecules are embedded. The lipid bilayer gives fluidity and elasticity to the membrane.

The process of expelling of food in amoeba is called egestion.

When a sufficient amount of undigested food gets collected in the food vacuole, it is thrown out of the body by rupturing cell membrane. The process of removal of undigested food from the body is called egestion.

A prototoxin is inactive toxin.

A protoxin is a chemical compound that only becomes a toxin after it is altered in some way, therefore it is also called an inactive toxin. It is a precursor of a toxin. Eg- Bt protoxins become toxic, after being chemically altered by the alkaline pH present inside the gut of certain insects.

Funaria is the example of bryophyte.

Funaria is a genus of approximately \(210\) species of moss. Funaria hygrometrica is the most common species. Funaria hygrometrica is called “cord moss” because of the twisted seta which is very hygroscopic and untwists when moist.

Theophrastus, a pupil of Aristotle is known as Father of Botany. Aristotle is called Father of Zoology as well as Biology and Louis Pasteur is considered to be Father of Microbiology.

The Mediterranean orchid Ophrys employs sexual deficit to get pollination done by a species of bee. One petal of its flower bears an uncanny resemblance to the female of the bee in size, colour and markings.

Melanisation of peppered moth in industrial areas is an effect of natural selection, where due to change in environmental conditions, of the two moth forms that existed - the grey and black, the black was favored by natural selection over the grey, as the grey were easily spotted by its predator.

Blood plasma carries food molecules, nitrogenous wastes, salts, carbon dioxide, hormones proteins, etc. in a dissolved form to the parts of the body that need it. Cells also put their waste products into the plasma.

Colchicine, a drug, which inhibits spindle fiber formation during mitosis and halts cell division at metaphase. This often will result in a doubling of the chromosome number since colchicine typically inhibits cytokinesis, but not karyokinesis. The doubled chromosomes will fuse within a single nucleus, thus diploidising the haploid cell.

Honey bees are involved in the fluid feeding mode.

Fluid-feeding insects, such as butterflies, moths and flies (\(20\%\) of all animal species), are faced with the common selection pressure of having to remove and feed on trace amounts of fluids from porous surfaces.