Biology - 1 - Free MCQ Practice Test with solutions, Bank Exams General

Bat echolocation is a perceptual system where ultrasonic sounds are emitted specifically to produce echoes. By comparing the outgoing pulse with the returning echoes, the brain and auditory nervous system can produce detailed images of the bat's surroundings. This allows bats to detect, localize and even classify their prey in complete darkness. At 130 decibels in intensity, bat calls are some of the most intense, airborne animal sounds.

Vitamin K is a group, of structurally similar, fat-soluble vitamins that are needed for the post translational modification of certain proteins required for blood coagulation and in metabolic pathways in bone and other tissue.

Red Blood cells contain haemoglobin which is what the oxygen binds with to form oxyhaemoglobin which is then transported to the different cells around the body. Oxygen bonds with the haemoglobin when it is at high partial pressure and then is released when there is a lower partial pressure of oxygen. At high altitudes there is lower atmospheric pressure of oxygen. This means that the current number of red blood cells in the body cannot meet the cells demands for oxygen.

White blood cells, or leukocytes, are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a hematopoietic stem cell. They live for about three to four days in the average human body. Leukocytes are found throughout the body, including the blood and lymphatic system.

The body keeps its core temperature constant at about 37 C by physiological adjustments controlled by the hypothalamus (Thermostat Center) where there are neurons sensitive to changes in skin and blood temperatures. The temperature-regulating centers are found in the Preoptic Area (the anteriorportion of the hypothalamus). This area receives input from temperature receptors in the skin and mucous membranes (Peripheral Thermoreceptors) and from internal structures (Central Thermoreceptors), which include the hypothalamus itself. 

Pathogenic bacteria secrete various virulence factors, including toxins, lipases and pro-teases that allow them to infect, breakdown and colonize host tissue. Among various modes of action that the pathogenic bacteria use to damage the host, pore formation (by pore forming toxins (PFTs)) and lipid hydrolysis (by phospholipases) modes are common in damaging the eukaryotic cell membrane. PFTs in their monomeric form are extracellular diffusible and able to form hydrophilic pores in cell membrane while phospholipases cleaves and hydrolyzes the ester bonds of most phospholipids in cell membrane.

Our bones and teeth are generally made up of Tricalcium Phosphate. Tricalcium phosphate is a calcium salt of phosphoric acid with the chemical formula Ca004)2. It is also known as tribasic calcium phosphate and bone phosphate of lime, BPL. Calcium phosphate is one of the main combustion products of bone.

Angora wool refers to the downy coat produced by the Angora rabbit. Angora is known for its softness, thin fibres, and what knitters refer to as a halo (fluffiness). It is also known for its silky texture. It is much warmer and lighter than wool due to the hollow core, Angora rabbits produce coats in a variety of colours, from white through tan, gray, and brown to black

Wood is a porous material and will absorb moisture from the air. Moisture is attracted to the walls of the tubes that make up the wood. Wood will only decay if it is in contact with the ground or wetted by an external source of moisture, such as rain seepage, plumbing leaks, or condensation. Dry wood will never decay. Also, the drier the wood, the less likely it is to be attacked by most types of woodinhabiting insects.

Ampicillin is the large spectrum anti-biotic most commonly used. Ampicillin is a beta-lactam antibiotic that is part of the aminopenicillin family and is roughly equivalent to its successor, amoxicillin in terms of spectrum and level of activity. It can sometimes result in reactions that range in severity from a rash (in the case of patients that may unwittingly have mononucleosis) to potentially lethal allergic reactions such as anaphylaxis.

Poliomyelitis, often called polio or infantile paralysis, is an acute, viral, infectious disease spread from person to person, primarily via the fecal-oral route. The term derives from the Greek polias, meaning "grey", myelOs, referring to the grey matter of the spinal cord, and the suffixitis, which denotes inflammation., i.e., inflammation of the spinal cord's grey matter, although a severe infection can extend into the brainstem and even higher structures, resulting in polioencephalitis, producing apnea that requires mechanical assistance such as an iron lung. 

Thiamine also called vitamin B 1, named as the "thio-vitamine" ("sulfurcontaining vitamin") is a watersoluble vitamin of the B complex. First named aneurin for the detrimental neurological effects if not present in the diet, it was eventually assigned the generic descriptor name vitamin B 1. Its phosphate derivatives are involved in many cellular processes. 

Adrenaline is a hormone produced by the adrenal glands during high stress or exciting situations. This powerful hormone is part of the human body's acute stress response system, also called the "fight or flight" response. It works by stimulating the heart rate, contracting blood vessels, and dilating air passages, all of which work to increase blood flow to the muscles and oxygen to the lungs.

Cloves are the aromatic dried flower buds of a tree in the family Myrtaceae. Cloves are native to the Maluku islands in Indonesia and used as a spice in cuisines all over the world. Cloves are harvested primarily in Indonesia, India, Madagascar, Zanzibar, Pakistan, and Sri Lanka. They have a numbing effect on mouth tissues. The clove tree is an evergreen that grows to a height ranging from 8-12 ma, having large leaves and sanguine flowers in numerous groups of terminal clusters.

Ketone bodies are three watersoluble compounds that are produced as byproducts when fatty acids are broken down for energy in the liver. Two of the three are used as a source of energy in the heart and brain while the third is a waste product excreted from the body. When the rate of synthesis of ketone bodies exceeds the rate of utilization, their concentration in blood increases, this is known as ketonemia. 

Antibodies are secreted by a type of Lymphocytes (White Blood cell). Antibodies can occur in two physical forms, a soluble form that is secreted from the cell, and a membranebound form that is attached to the surface of a B cell and is referred to as the B cell receptor (BCR). An antibody (Ab), also known as an immunoglobulin (Ig), is a large Y-shaped protein produced by lymphocytes that is used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, called an antigen.

Proteins are large biological molecules consisting of one or more chains of amino acids are essential nutrients for the human body. They are one of the building blocks of body tissue, and can also serve as a fuel source. As fuel, proteins contain 4 kcal per gram, just like carbohydrates and unlike lipids, which contain 9 kcal per gram.

A biopsy is a medical test commonly performed by a surgeon or an interventional radiologist involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. When cancer is suspected, a variety of biopsy techniques can be applied. An excisional biopsy is an attempt to remove an entire lesion. When the specimen is evaluated, in addition to diagnosis, the amount of uninvolved tissue around the lesion, the surgical margin of the specimen is examined to see if the disease has spread beyond the area biopsied.

Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.

Toxicology is the study of the adverse effects of chemicals on living organisms. It is the study of symptoms, mechanisms, treatments and detection of poisoning, especially the poisoning of people. The relationship between dose and its effects on the exposed organism is of high significance in toxicology. The chief criterion regarding the toxicity of a chemical is the dose, i.e. the amount of exposure to the substance. All substances are toxic under the right conditions.