Biology MCQ Questions with answers

No Explanation found. Add Explanation and get +2 points.

No Explanation found. Add Explanation and get +2 points.

Explanation:
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.

Explanation:
Red Blood cells contain haemoglobin which is what the oxygen bindswith 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.

Explanation:
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.

Explanation:
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.

Explanation:
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.

Explanation:
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.

Explanation:
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.

Explanation:
Ampicillin is the large spectrum anti-biotic most commonly used. Ampicillin is a beta-lactam antibiotic that is part of the amino- penicillin 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.