Test: Human Blood - UPSC MCQ

The large molecules found on the surface of red blood cells (RBCs) are called antigens. Antigens are substances that can stimulate an immune response in the body. In the context of blood typing, different blood types are determined by the presence or absence of specific antigens on the surface of red blood cells. These antigens can trigger the production of antibodies in individuals who lack those specific antigens, leading to an immune response if incompatible blood types are mixed.

The most common component of plasma, other than water, is protein. Plasma is the liquid component of blood and contains a variety of substances, including proteins, electrolytes, hormones, waste products, and nutrients. Among these components, proteins make up a significant portion of plasma. These proteins include albumin, globulins, and fibrinogen, among others. They play essential roles in maintaining osmotic balance, transporting substances, regulating immune responses, and contributing to blood clotting. While oxygen, urea, and iron can be found in plasma, proteins are the most abundant and prevalent component, making them the correct answer.

The average blood volume for an adult is about 5 liters. This value can vary depending on factors such as body size, age, sex, and overall health. However, 5 liters is a commonly accepted estimate for the average blood volume in an adult human.

Haemoglobin consists of iron in its cells, and it turns red when it combines with oxygen. Oxygen binds to the iron component of haemoglobin, forming a complex known as oxyhemoglobin. This complex gives oxygenated blood its bright red color. When oxygen is released from haemoglobin, such as in tissues where oxygen is needed, the color of the blood becomes darker, appearing more bluish-red.

The term erythrocytes is another name for red blood cells (RBCs). Therefore, the correct answer is option a) Red blood cells. Erythrocytes are the most abundant type of blood cell and are responsible for transporting oxygen throughout the body. White blood cells (leukocytes) and platelets (thrombocytes) are distinct types of cells with different functions in the bloodstream.

The healthy range for hemoglobin for women is typically considered to be option a) 11.6 to 15 grams per deciliter (g/dL). Hemoglobin levels can vary slightly depending on factors such as age, pregnancy, and individual health conditions. However, the range mentioned in option a is a commonly accepted range for healthy hemoglobin levels in adult women. It's important to note that specific reference ranges may vary slightly depending on the laboratory and healthcare provider.

The percentage of body weight that is blood varies depending on factors such as age, sex, and overall health. On average, blood makes up about 7-8% of a person's total body weight. So the correct answer would be option d) 8%.

There are four main blood groups: A, B, AB, and O. These blood groups are determined by the presence or absence of certain antigens on the surface of red blood cells. Additionally, blood can be further classified based on the presence or absence of the Rh antigen, resulting in the positive (+) or negative (-) designation, such as A+, A-, B+, B-, AB+, AB-, O+, and O-.

White blood cells, also known as leukocytes, play a vital role in fighting infections and protecting us from diseases. They are an essential part of the immune system and are responsible for recognizing and attacking foreign substances, such as bacteria, viruses, and other pathogens. White blood cells are involved in various immune responses, including engulfing and destroying pathogens, producing antibodies, and coordinating immune reactions.

The pH value of human blood is around 7.4, making it slightly alkaline. The pH scale ranges from 0 to 14, with values below 7 considered acidic, 7 considered neutral, and values above 7 considered alkaline or basic. The slightly alkaline pH of blood is crucial for maintaining proper physiological function and is carefully regulated by the body's acid-base balance mechanisms.