Biology Test - 38

Taxa whose number have been reduced to a critical level or whose habitats have been so drastically reduced that they are deemed to be immediate danger of extinction are known as endangered animals, e.g. lion tailed macaque, crocodile, musk deer, rhino, etc.

The number of mitochondria increases in cells ofGerminating seeds.

Seed germination is the phase of intense biochemical activity. The reserve food materials are rapidly oxidised and release energy for various biosynthetic activities going on in the germinating seed. Thus, during seed germination, number of mitochondria increases to fulfil the requirement of energy.

Malaria has long been treated with plant-based medicine.Quinine, which comes from the bark of a cinchona tree, was first isolated as an antimalarial compound in the 1800s, though there is evidence that bark extracts have been used to treat malaria since the 1600s.The cinchona tree is native to Peru.Cinchona is used in eye lotions to numb pain, kill germs, and as an astringent.Thereby, the correct answer is Chinchona.

Eucalyptus Plant:

• It has medicinal properties which can cure Bronchitis, Gingivitis etc.
• However, concentrated Eucalyptus oil's consumption can be toxic to human beings.

Quercus:

• It is also known by the name oak, it has many medicinal properties
• It is used in the treatment of asthma, hemorrhoid, diarrhea, gastric ulcers, and wound healing.

​Betula:

• It belongs to the family Betulaceae, it is used traditionally to cure several diseases like inflammatory diseases including arthritis.

Tundra forestsmajorly comprises of lichens and mosses.

• In Tundra Biome, tree growth is hindered by low temperatures and short growing seasons.
• Dwarf Shrubs, mosses, lichens, etc., and scattered trees are also found in tundra forests.
• The ecological boundary (ecotone) between the tundra and taiga forests is called a tree line or timberline.

Bacteria protect themselves from viruses by fragmenting viral DNA withan endonuclease. The endonuclease is also known as restriction enzyme which is a protein that is produced by bacterial cells which leaves DNA at specific sites along with the molecule.Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain.

A. Gonorrhoea - Gonorrhoea is a sexually transmitted infection (STI) caused by bacteria called Neisseria gonorrhoeae or gonococcus.

B. Syphilis - Syphilis is a chronic bacterial infection that can be transmitted through sexual contact. Syphilis is caused by a type of bacteria known as Treponema pallidum.

C. Genital warts - Genital warts are a type of sexually transmitted disease (STD). The disease causes warts (small bumps or growth ) to form in and around the genitals and rectum. it is caused by Human Papilloma virus.

Passive immunity in newborn babies is due to IgG.

IgG antibodies are actively produced in response to antigenic challenge or passively administered as an effective form of immunotherapy to confer immunity against foreign antigens.

Veillonella is an anaerobic gram-negative cocci.

Among gram-negative anaerobic cocci, Veillonella species are common and considered mainly harmless, or even beneficial, colonizers of the mouth from the early years of life onward,31 whereas Acidaminococcus and Megasphaera spp. reside in the human intestine and genitourinary tract, respectively.

Smooth muscles fibers are non-striated cells because they contain a large proportion of thin filament than thick filaments but striation occur due to regular alternate arrangement of thick and thin filaments. Since smooth muscles have more thin filaments, the alternate arrangement of thick and thin filaments is not possible and therefore are unstriated.

So, both Assertion and Reason are correct Reason is the correct explanation for Assertion.

Drosophila flies with XXY genotype are females, but human beings with such genotype are abnormal males. It shows that Y-chromosome is male determinator in human beings.

In the case of mammals, sex is determined using sex chromosomes. The primary sex is determined by whether an organism has an XX or an XY karyotype. Females have two X-chromosomes in all their somatic cells whereas males have one X and one Y chromosome. Individuals with a Y-chromosome will develop into a male, independent of the number of X-chromosomes. But the individual without the Y-chromosome will develop into a female. In the case of secondary sex determination, the male or female sex is determined by the hormones produced by gonads.

In the case of Drosophila, the sex of an individual is not determined by the Y-chromosome. The genes present on the Y-chromosome are responsible for sperm formation in adults. Sex is determined by the balance of autosomal alleles and the X-chromosome. A normal diploid male contains two sets of autosomes and XY-chromosomes. A normal diploid female has 2 sets of autosomes and two X-chromosomes.

Drosophila flies with XXY genotype are females, but human beings with such genotypes are abnormal males. It shows that the Y chromosome is the male determiner in human beings.