Biology MCQs

Notes:
Glycolysis, part of cellular respiration, is a series of reactions that constitute the first phase of most carbohydrate catabolism, catabolism meaning the breaking down of larger molecules into smaller ones. Glycolysis breaks down glucose and forms pyruvate with the production of two molecules of ATP. The entire process from conversion of glucose to pyruvate is anaerobic that is it does not take place in presence of oxygen.

Notes:
The skin is the soft outer covering of vertebrates that guards the underlying muscles, bones, ligaments, and internal organs. The cutaneous membrane is the technical term for our skin. The skin’s primary role is to help protect the rest of the body’s tissues and organs from physical damage such as abrasions, chemical damage such as detergents, and biological damage from micro organisms. Our skin is made of three general layers. In order from most superficial to deepest they are the epidermis, dermis, and subcutaneous tissue.

Notes:
The chromosomes which determine the sex (maleness or femaleness) of an individual in sexually producing organisms are called sex chromosomes or allosomes. In humans an individual whose cells contain XX chromosomes (homo or isogametic) becomes a female, while one whose cells contains XY chromosomes (heterogametic) becomes a male.

Notes:
Animal and vegetable fats serve as a concentrated energy source and are the highest energy sources in feedstuffs. Dietary fats and oils are a concentrated source of energy when compared to carbohydrate and protein, having over twice the amount of calories per gram.  Fats contain 2.25 times the calories per gram than protein or carbohydrates. Fats contain 9 calories/gm while protein and carbohydrates contain 4 calories per gram.

Notes:
Human immunodeficiency virus (HIV) attacks and kills crucial immune system cells, known as T-helper cells. A T cell, or T lymphocyte, is a type of lymphocyte (a subtype of white blood cell) that plays a central role in cell-mediated immunity. They are called T cells because they mature in the thymus from thymocytes.

Notes:
Heart rate is the speed of the heartbeat measured by the number of contractions of the heart per minute (bpm). Conventionally, a normal adult has a heartbeat rate of 72 per minute. However, the heart rate can vary according to the body’s physical needs, including the need to absorb oxygen and excrete carbon dioxide.

Notes:
Wolffia is a genus of 9 to 11 species which include the smallest flowering plants on Earth. Commonly called water-meal or duckweed, these aquatic plants resemble specks of cornmeal floating on the water. Wolffia species are free-floating thalli, green or yellow-green, and without roots. The flower is produced in a depression on the top surface of the plant body. It has one stamen and one pistil.

Notes:
Tears are a clear liquid secreted by the lacrimal glands (tear ducts) in the eyes of all land mammals. The lacrimal glands are situated in the upper lateral region of each orbit, in the lacrimal fossa of the orbit formed by the frontal bone. They are paired, almond-shaped exocrine glands, one for each eye.

Notes:
Vitamin B contains nitrogen atoms that allow them to participate in regulating metabolism. For example, Vitamin B3 is a water soluble vitamin containing compound Niacin or Niacinamide, a nitrogen containing vitamin.

Notes:
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. It is distinct from other liquid compounds found inside plants or exuded by plants, such as sap, latex, or mucilage.