Biology MCQs

Notes:
Lymphocytes are a type of white blood cell that are part of the immune system. Their main function is to produce antibodies that protect the body from foreign invaders, such as viruses, bacteria, and toxins. These antibodies help the body respond to and eliminate foreign invaders, which provides protection against infectious diseases.
Lymphocytes also help the body’s immune system remember every antigen it comes in contact with. After an encounter, some lymphocytes turn into memory cells.
There are two main types of lymphocytes: B cells and T cells. B cells produce antibodies that attack invading bacteria, viruses, and toxins. T cells destroy the body’s own cells that have been taken over.
If you have low numbers of lymphocytes (lymphopenia), you are at higher risk of infection. Symptoms can range from mild to serious and are correlated to the severity of the lymphopenia as well as its duration. Some people have no symptoms.

Notes:
Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the sub-phylum Medusozoa. Jellyfish do not have specialized systems for osmoregulation, respiration and circulation, and do not have a central nervous system.

Notes:
Each kidney is made of tube like structures called nephrons (renal tubules). A nephron is the structural and functional unit of the kidney. The cup-shaped upper end called Bowman’s capsule, has a network of capillaries within it called glomerulus. Glomerulus is a knot of capillaries formed from the artery which brings blood containing wastes and excess of water to the kidney. Bowman’s capsule leads into a tubular structure.

Notes:
The pituitary gland or hypophysis is located in one of the bones at the base of the skull. It has two portions viz. anterior hypophysis and posterior hypophysis.
The anterior part produces two hormones that work directly viz. growth hormone (GH) and prolactin; and four tropic hormones {tropic hormones regulate the other endocrine glands} viz. adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
The posterior part releases two hormones produced in the hypothalamus viz. oxytocin and antidiuretic hormone (ADH or vasopressin).

Notes:
Human can listen only the frequencies below 20 kHz. However animals like dogs, cats, dolphins, bats, and mice can listen above this limit. This principle was used by Galton who produced the ultrasonic waves by blowing a whistle. For human these whistle appears silent, while dogs and cats can listen it. It is used in training of dogs and cats

Notes:
Reptiles and Amphibians have a mixed heart.

Notes:
Kernel smut of rice normally is a minor disease. Damage is caused by the endosperm of the rice grain being replaced by masses of black fungal spores. Sheath blight disease caused by the fungus Rhizoctonia solani. This fungus is very widespread in agricultural crops.

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Vitamin B3 protects us from Pellagra disease. Vitamin B-3 is important for a healthy body and may help to slow the progression of heart disease, diabetes, etc. It aids your metabolism and nervous system.

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The theory of origin of life on earth is proposed by Haldane. Further this theory was confirmed by the experiments conducted by Stanley L. Miller and Harold C. Urey.

Notes:
As altitude increases, the availability of oxygen decreases, making the air thinner and drier. Dry climates can cause drying and cracking inside the nose, which can lead to a nosebleed. The climate inside nose gets drier. This makes the blood vessels exposed inside your nose more likely to burst there than at lower altitudes.