Biology MCQs

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In the human body, there are a total of 12 pairs of ribs. Out of these, the first 7 pairs are referred to as “true ribs.” True ribs are so named because they are directly connected to the sternum (breastbone) through their own costal cartilages. Each true rib consists of a bony portion that connects to the spine and a cartilaginous portion that attaches to the sternum.

These true ribs play a crucial role in protecting the internal organs within the thoracic cavity, including the heart and lungs. The remaining 5 pairs of ribs are known as “false ribs” – they are either indirectly connected to the sternum or not connected at all. False ribs are attached to each other through cartilage or are floating freely, not attaching to the sternum directly.

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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.

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Hypoglycemia is a condition in which your blood sugar which is also called as glucose is lower than normal in human body. Diabetes treatment and other conditions can cause hypoglycaemia.

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Genes helps to determine the character of a cell. Gene is the basic physical and functional unit of heredity and are made up of DNA. Some of the genes act as instructions to make molecules called proteins.

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Hodophobia is the fear of travel. It is also referred to as travel phobia or fear of travel. Acute anxiety which is provoked by travel can be treated with anti-anxiety medication.

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As cells develop some genes are turned off permanently. All of the cells within a complex multicellular organism such as a human being contain the same DNA; however, the body of such an organism is clearly composed of many different types of cells. What, then, makes a liver cell different from a skin or muscle cell? The answer lies in the way each cell deploys its genome. In other words, the particular combination of genes that are turned on (expressed) or turned off (repressed) dictates cellular morphology (shape) and function. This process of gene expression is regulated by cues from both within and outside cells, and the interplay between these cues and the genome affects essentially all processes that occur during embryonic development and adult life. This means that cells become specialized because the genes that are not required are switched off. Only the genes needed to make a particular type of cell work are switched on. So muscle cells only have the genes needed to make muscle cell proteins switched on. All the other genes, such as those needed to make blood cell proteins and nerve cell proteins, are switched off. But the stem cells are unspecialized and can develop into various tissues.

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A mule is the offspring of a male donkey (a jack) and a female horse (a mare). A horse has 64 chromosomes, and a donkey has 62. The mule ends up with 63. Mules can be either male or female, but, because of the odd number of chromosomes, they can’t reproduce

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Xylem is a type of tissue in vascular plants that transports water and some nutrients from the roots to the leaves. Water is passively transported into the roots and then into the xylem. The forces of cohesion and adhesion cause the water molecules to form a column in the xylem.

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The retina is a thin membrane which covers the inside back of the eye. Like film in a camera, the retina is the light-sensitive surface where images from the outside world come to a focus.

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The pituitary gland is a small pea-sized gland that plays a major role in regulating vital body functions and general wellbeing. Through secretion of its hormones, the pituitary gland controls metabolism, growth, sexual maturation, reproduction, blood pressure and many other vital physical functions and processes.