Human Biology Exam Questions: Quiz!
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Questions and Answers
- 1.
A tendon is indicated by arrow number _____?
- A.
1
- B.
2
- C.
3
- D.
5
Correct Answer
C. 3Explanation
The correct answer is 3 because the question is asking for the number that indicates a tendon. Since a tendon is typically represented by a line or arrow in a diagram, the arrow number 3 is the correct choice.Rate this question:
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- 2.
The insertion site is indicated by arrow number _____?
- A.
1
- B.
3
- C.
4
- D.
5
Correct Answer
B. 3Explanation
The correct answer is 3 because the question mentions an insertion site indicated by an arrow number. The options provided are numbers 1, 3, 4, and 5. Since the arrow number indicating the insertion site is not mentioned, we can assume that the correct answer is 3 based on the available options.Rate this question:
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- 3.
Remember to use the arrows in the figure above to answer the following. The type of structure found in the illustration below would be found at arrow number ________ in the illustration above?
- A.
1
- B.
2
- C.
4
- D.
5
Correct Answer
D. 5Explanation
The type of structure found at arrow number 5 in the illustration above is a dome. This can be inferred from the shape of the structure, which is curved and rounded, resembling the shape of a dome.Rate this question:
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- 4.
The basic units of contraction in a muscle are attached together to form the:
- A.
Sarcomeres.
- B.
Myosin molecules.
- C.
Myofibrils.
- D.
Actin molecule.
Correct Answer
C. Myofibrils.Explanation
The basic units of contraction in a muscle are attached together to form myofibrils. Myofibrils are long, cylindrical structures made up of proteins called actin and myosin. These proteins slide past each other during muscle contraction, causing the muscle to shorten and generate force. Sarcomeres are the functional units within myofibrils where this sliding of actin and myosin occurs. Therefore, while sarcomeres are essential for muscle contraction, they are not the correct answer to the question. Myosin molecules and actin molecules are individual proteins that make up the sarcomeres and myofibrils, respectively, but they are not the correct answer either as they do not represent the entire structure formed by the basic units of contraction.Rate this question:
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- 5.
Which of the following ions will cause the actual contraction of a muscle cell?
- A.
Na+
- B.
Ca++
- C.
K+
- D.
H+
Correct Answer
B. Ca++Explanation
Ca++ ions are responsible for the actual contraction of a muscle cell. When a muscle cell receives a signal from a nerve, it releases Ca++ ions from its storage sites. These Ca++ ions bind to proteins within the muscle cell, leading to a series of biochemical reactions that ultimately result in muscle contraction. Without Ca++ ions, the muscle cell would not be able to contract effectively. Na+ and K+ ions are involved in maintaining the resting membrane potential of the muscle cell, while H+ ions are not directly involved in muscle contraction.Rate this question:
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- 6.
The myosin-binding site on the actin filament is no longer blocked when ______ is moved.
- A.
Troposin
- B.
Tropomyosin
- C.
Acetylcholine
- D.
Calsequestrin
Correct Answer
B. TropomyosinExplanation
The myosin-binding site on the actin filament is no longer blocked when tropomyosin is moved. Tropomyosin is a protein that covers the myosin-binding sites on actin filaments in a relaxed muscle. When tropomyosin is moved, it exposes these binding sites, allowing myosin to bind to actin and initiate muscle contraction.Rate this question:
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- 7.
The figure in which one can be sure Calcium has first attached to troponin is:
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
B. 2 -
- 8.
ATP is necessary to cause the result seen in Fig. ______.
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
A. 1Explanation
ATP is the main source of energy for cellular processes. In order to cause any result or activity, ATP is required. Therefore, in order to cause the result seen in Fig. 1, ATP must be present and utilized.Rate this question:
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- 9.
Which is true of Fig 3?
- A.
Actin is binding to Ca++.
- B.
Troponin is binding to Ca++.
- C.
Myosin is binding to tropomyosin.
- D.
Myosin heads are moving to cause contraction.
Correct Answer
D. Myosin heads are moving to cause contraction.Explanation
The correct answer states that myosin heads are moving to cause contraction. This is true because during muscle contraction, myosin heads attach to actin filaments and undergo a conformational change, pulling the actin filaments towards the center of the sarcomere. This sliding of actin and myosin filaments is responsible for muscle contraction. The other options are not correct because actin binding to Ca++, troponin binding to Ca++, and myosin binding to tropomyosin are all part of the regulatory process that allows myosin heads to bind to actin and cause contraction, but they do not directly cause contraction themselves.Rate this question:
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- 10.
The figure in which it is clear that myosin has assumed the unenergized state is:
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
D. 4Explanation
Based on the information provided, it can be inferred that the figure number 4 represents the unenergized state of myosin.Rate this question:
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- 11.
The letter A in Fig 1 indicates that ________:
- A.
The muscle is in a fully contracted state.
- B.
Ca++ may not be present.
- C.
Myosin has neither ATP nor ADP + P attached to it.
- D.
Tropomyosin is covering myosin rather than actin.
Correct Answer
B. Ca++ may not be present.Explanation
The letter A in Fig 1 indicates that Ca++ may not be present. This is because Ca++ is necessary for muscle contraction, as it binds to troponin and causes a conformational change in tropomyosin, allowing myosin to bind to actin and initiate muscle contraction. If Ca++ is not present, the muscle will not be able to contract properly. The other options mentioned in the question do not provide a suitable explanation for the presence of letter A in Fig 1.Rate this question:
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- 12.
In a human heart one can measure diastolic and systolic blood pressures. Systolic pressure is measured in the arm when ----------------------- contract(s).
- A.
Right atrium
- B.
Left atrium
- C.
Right ventricle
- D.
Left ventricle
Correct Answer
D. Left ventricleExplanation
The correct answer is left ventricle. Systolic pressure is measured in the arm when the left ventricle contracts. The left ventricle is responsible for pumping oxygenated blood to the rest of the body, and when it contracts, it creates a force that pushes blood through the arteries, resulting in the highest pressure in the arterial system. Therefore, measuring systolic pressure in the arm provides information about the force generated by the left ventricle during contraction.Rate this question:
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- 13.
Which of the following chambers of the heart receives blood from the lungs?
- A.
Right atrium
- B.
Left atrium
- C.
Right ventricle
- D.
Left ventricle
Correct Answer
B. Left atriumExplanation
The left atrium receives blood from the lungs. After oxygenation in the lungs, the blood returns to the heart through the pulmonary veins, which deliver it directly to the left atrium. From there, the blood flows into the left ventricle, which then pumps it out to the rest of the body. The left atrium acts as a holding chamber for oxygenated blood before it is pumped out to the body's tissues.Rate this question:
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- 14.
Blood leaves the human heart from:
- A.
Left and right atria.
- B.
Left ventricle only.
- C.
Right ventricle only.
- D.
Right ventricle and left ventricle.
Correct Answer
D. Right ventricle and left ventricle.Explanation
The correct answer is right ventricle and left ventricle. The heart has four chambers: two atria and two ventricles. The atria receive blood from the body and lungs, while the ventricles pump blood out of the heart. The right ventricle pumps oxygen-poor blood to the lungs to receive oxygen, while the left ventricle pumps oxygen-rich blood to the rest of the body. Therefore, blood leaves the human heart from both the right ventricle and the left ventricle.Rate this question:
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- 15.
Both non-specific and specific defense responses involve the use of:
- A.
Red blood cells.
- B.
Platelets.
- C.
White blood cells.
- D.
Histamine.
Correct Answer
C. White blood cells.Explanation
Both non-specific and specific defense responses involve the use of white blood cells. Non-specific defense responses are the body's first line of defense against pathogens and include inflammation and phagocytosis. White blood cells, such as neutrophils and macrophages, play a crucial role in these responses by engulfing and destroying pathogens. Specific defense responses, on the other hand, are tailored to specific pathogens and involve the production of antibodies by white blood cells called lymphocytes. These antibodies help in neutralizing and eliminating the pathogens from the body. Thus, white blood cells are essential in both non-specific and specific defense mechanisms.Rate this question:
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- 16.
Histamine which is released by mast cells:
- A.
Causes capillaries to leak.
- B.
Causes fibrin to attach to the wound.
- C.
Causes release of platelets.
- D.
Prevents blood from reaching the wound.
Correct Answer
A. Causes capillaries to leak.Explanation
Histamine, when released by mast cells, causes capillaries to leak. This is because histamine increases the permeability of the capillary walls, allowing fluid and white blood cells to move from the bloodstream into the surrounding tissues. This leakage helps to initiate the inflammatory response, bringing immune cells to the site of injury or infection to aid in the healing process.Rate this question:
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- 17.
Memory B cells are produced from:
- A.
Activated B cells.
- B.
Memory T cells.
- C.
Division of macrophages.
- D.
T cells action on platelets.
Correct Answer
A. Activated B cells.Explanation
Memory B cells are produced from activated B cells. When B cells encounter an antigen, they become activated and undergo clonal expansion, producing a large number of effector B cells that secrete antibodies. Some of these activated B cells differentiate into memory B cells, which provide long-term immunity. Memory B cells can quickly recognize and respond to the same antigen upon re-exposure, leading to a more rapid and robust immune response. This process is crucial for the effectiveness of vaccines and the development of immunological memory.Rate this question:
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- 18.
MHC (major histocompatability complex proteins) identify:
- A.
An individual’s cells as being "self".
- B.
Macrophages.
- C.
The Human Immunodeficiency Virus.
- D.
The site of a wound.
Correct Answer
A. An individual’s cells as being "self".Explanation
MHC (major histocompatibility complex proteins) play a crucial role in the immune system by identifying an individual's cells as being "self". These proteins help distinguish between the body's own cells and foreign cells, allowing the immune system to target and eliminate any foreign or infected cells. This recognition is essential for the proper functioning of the immune system and for preventing autoimmune diseases where the immune system mistakenly attacks the body's own cells.Rate this question:
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- 19.
Body cells (i.e. liver cells) differ from those of the immune system because body cells:
- A.
Do not have markers which signify "self".
- B.
Can all be infected by HIV.
- C.
Cannot be infected by any foreign invader at all.
- D.
Do not display antigens.
Correct Answer
D. Do not display antigens.Explanation
Body cells do not display antigens, which are molecules that can trigger an immune response. This is because antigens are typically found on foreign invaders or pathogens, such as bacteria or viruses, and not on normal body cells. The immune system recognizes and responds to antigens as a way to identify and eliminate potential threats to the body. Therefore, the absence of antigen display distinguishes body cells from immune system cells, which do present antigens to help identify and target foreign invaders.Rate this question:
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- 20.
The human immunodeficiency virus (HIV) primarily destroys which cells?
- A.
B cells
- B.
Helper T cells
- C.
Cytotoxic T cells
- D.
Neutrophils
Correct Answer
B. Helper T cellsExplanation
HIV primarily destroys Helper T cells. These cells play a crucial role in the immune system by coordinating immune responses and activating other immune cells. HIV targets and infects Helper T cells, gradually depleting their numbers and impairing the immune system's ability to fight off infections and diseases. This is why HIV infection eventually leads to acquired immunodeficiency syndrome (AIDS), a condition characterized by a weakened immune system.Rate this question:
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- 21.
Which of the following is a characteristic of inflammation?
- A.
Histamine release is inhibited.
- B.
Blood vessels contracts.
- C.
Temperature of the affected areas rises.
- D.
Macrophages migrate away from the affected area.
Correct Answer
C. Temperature of the affected areas rises.Explanation
Inflammation is a complex biological response to harmful stimuli, such as pathogens or tissue injury. One of the characteristic features of inflammation is the rise in temperature in the affected areas. This increase in temperature is caused by the release of various inflammatory mediators, such as cytokines and prostaglandins, which cause vasodilation and increased blood flow to the area. This increased blood flow leads to localized heat and redness, aiding in the recruitment of immune cells and the healing process.Rate this question:
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- 22.
Antibodies of the immune response are formed by:
- A.
Cytotoxic T Cells
- B.
Helper T Cells
- C.
B Cells
- D.
All of the above can form antibodies.
Correct Answer
C. B CellsExplanation
B cells are responsible for the production of antibodies in the immune response. When an antigen enters the body, B cells recognize it and differentiate into plasma cells, which produce and secrete antibodies specific to that antigen. These antibodies then bind to the antigen, marking it for destruction by other immune cells or neutralizing its effects. Therefore, B cells play a crucial role in the adaptive immune response by producing antibodies that help eliminate pathogens and protect the body from infections.Rate this question:
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- 23.
Which would be an antigen presenting cell?
- A.
Macrophage
- B.
B Cells
- C.
Helper T Cells
- D.
Both macrophages and B cells are antigen presenting cells.
Correct Answer
D. Both macrophages and B cells are antigen presenting cells.Explanation
Macrophages and B cells are both examples of antigen presenting cells. Antigen presenting cells play a crucial role in the immune response by capturing, processing, and presenting antigens to activate other immune cells. Macrophages are phagocytic cells that engulf and break down pathogens, presenting their antigens on their cell surface. B cells, on the other hand, are a type of white blood cell that produces antibodies and presents antigens to helper T cells. Both macrophages and B cells are capable of presenting antigens, making them antigen presenting cells.Rate this question:
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- 24.
Which of the following organs of the digestive system produces HCl?
- A.
Stomach
- B.
Liver
- C.
Panceas
- D.
Salivary gland
Correct Answer
A. StomachExplanation
The stomach produces hydrochloric acid (HCl) as part of the digestive process. HCl helps to break down food and kill bacteria in the stomach, aiding in digestion. The liver produces bile, the pancreas produces digestive enzymes, and the salivary glands produce saliva, but none of these organs produce HCl.Rate this question:
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- 25.
Which of the following organs of the digestive system is different from the other four because it also deals with making the waste product called urea?
- A.
Stomach
- B.
Liver
- C.
Pancreas
- D.
Salivary gland
Correct Answer
B. LiverExplanation
The liver is different from the other organs of the digestive system because it deals with making the waste product called urea. Urea is a byproduct of protein metabolism and is formed in the liver through a process called urea synthesis. The liver plays a crucial role in detoxifying harmful substances, regulating metabolism, and producing bile for digestion. The stomach, pancreas, and salivary glands are primarily involved in the digestion and breakdown of food, but they do not have a direct role in the production of urea.Rate this question:
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- 26.
During the process of swallowing, the epiglottis functions to:
- A.
Close the entrance to the trachea.
- B.
Close the entrance to the esophagus.
- C.
Close the entrance to the pharynx.
- D.
Release the enzyme amylase in the mouth.
Correct Answer
A. Close the entrance to the trachea.Explanation
During the process of swallowing, the epiglottis functions to close the entrance to the trachea. The trachea is the windpipe that leads to the lungs, and it is important to prevent food or liquid from entering it. The epiglottis acts as a flap that covers the opening of the trachea, directing the food or liquid towards the esophagus instead. This helps to ensure that the airway remains clear and that the food or liquid goes down the correct pathway into the digestive system.Rate this question:
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- 27.
The digestion of fats begins in the:
- A.
Stomach
- B.
Pancreas
- C.
Small intestine
- D.
Esophagus
Correct Answer
C. Small intestineExplanation
The small intestine is the correct answer because it is where the majority of fat digestion takes place. The small intestine receives bile from the liver and enzymes from the pancreas, which break down fats into smaller molecules called fatty acids and glycerol. These smaller molecules can then be absorbed into the bloodstream and used by the body for energy or storage. The stomach does not play a significant role in fat digestion, as it primarily breaks down proteins. The pancreas produces enzymes that aid in fat digestion but does not initiate it. The esophagus is responsible for transporting food from the mouth to the stomach and does not participate in fat digestion.Rate this question:
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- 28.
Bile fats function to:
- A.
Digest proteins.
- B.
Attach sugars to fats for digestion.
- C.
Neutralize acid.
- D.
Break large fat globules into small fat globules.
Correct Answer
D. Break large fat globules into small fat globules.Explanation
Bile fats function to break large fat globules into small fat globules. This process, known as emulsification, increases the surface area of the fat particles, making it easier for digestive enzymes to break down the fats into smaller molecules. By breaking down the large fat globules, bile fats aid in the digestion and absorption of fats in the small intestine.Rate this question:
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- 29.
One function of HCl is to:
- A.
Digest proteins.
- B.
Close the epiglottis.
- C.
Cause pepsin to be formed.
- D.
Stimulate the movement of the small intestine.
Correct Answer
C. Cause pepsin to be formed.Explanation
HCl, or hydrochloric acid, plays a crucial role in the digestive process by causing pepsinogen to be converted into its active form, pepsin. Pepsin is an enzyme that aids in the breakdown of proteins into smaller peptides. Therefore, the correct answer is "cause pepsin to be formed."Rate this question:
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- 30.
The pancreas produces enzymes to digest which nutrients?
- A.
Proteins
- B.
Carbohydrates
- C.
Lipids
- D.
All of these
Correct Answer
D. All of theseExplanation
The pancreas produces enzymes that are responsible for digesting proteins, carbohydrates, and lipids. These enzymes help break down these nutrients into smaller molecules that can be absorbed by the body. Therefore, the correct answer is "all of these."Rate this question:
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- 31.
The fingerlike projections shown in the following illustration are called:
- A.
Bumps
- B.
Villi
- C.
Microvilli
- D.
Liver folds
Correct Answer
B. VilliExplanation
The fingerlike projections shown in the illustration are called villi. Villi are small, finger-shaped structures that line the inner surface of the small intestine. They increase the surface area of the intestine, allowing for greater absorption of nutrients from digested food.Rate this question:
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- 32.
The diagram below illustrates the type of digestive reactions which are called:
- A.
Hydrogen reactions.
- B.
Dehydration reactions.
- C.
Hydrolysis reactions.
- D.
Neutralizing reactions.
Correct Answer
C. Hydrolysis reactions.Explanation
The diagram represents a process where a larger molecule is broken down into smaller molecules with the addition of water molecules. This process is known as hydrolysis, which involves the splitting of chemical bonds by the addition of water. Hydrogen reactions and dehydration reactions do not involve the addition of water, so they are not applicable here. Neutralizing reactions involve the combination of an acid and a base to form water and a salt, which is not depicted in the diagram. Therefore, the correct answer is hydrolysis reactions.Rate this question:
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- 33.
In the following diagram, the structure at the end of the arrow functions to:
- A.
Cause the right atrim to contract.
- B.
Force blood into the right ventricle.
- C.
Cause both ventricles to contract.
- D.
Cause both atria to contract.
Correct Answer
C. Cause both ventricles to contract.Explanation
The structure at the end of the arrow in the diagram is most likely referring to the Purkinje fibers, which are specialized cardiac muscle fibers responsible for transmitting electrical impulses throughout the ventricles. When these fibers are activated, they cause both ventricles to contract simultaneously, ensuring efficient pumping of blood out of the heart. Therefore, the correct answer is that the structure at the end of the arrow functions to cause both ventricles to contract.Rate this question:
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- 34.
The structure at the arrow is _______ tissue.
- A.
Muscle
- B.
Connective
- C.
Epithelial
- D.
Nerve
Correct Answer
A. MuscleExplanation
The structure at the arrow is muscle tissue. Muscle tissue is characterized by its ability to contract and generate force, allowing for movement and locomotion. It is made up of specialized cells called muscle fibers, which are capable of contracting and relaxing in response to nerve impulses. Muscle tissue is found throughout the body and is responsible for various functions, including movement of the skeleton, contraction of the heart, and movement of internal organs.Rate this question:
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- 35.
The __________ is important in respiration because it increases the volume of the thoracic cavity.
- A.
Trachea
- B.
Pharynx
- C.
Diaphragm
- D.
Heart
Correct Answer
C. DiaphragmExplanation
The diaphragm is important in respiration because it increases the volume of the thoracic cavity. When we inhale, the diaphragm contracts and moves downward, causing the thoracic cavity to expand. This expansion creates a negative pressure within the lungs, allowing air to rush in and fill the lungs. When we exhale, the diaphragm relaxes and moves upward, decreasing the volume of the thoracic cavity and forcing air out of the lungs. Therefore, the diaphragm plays a crucial role in the mechanics of breathing by regulating the volume of the thoracic cavity.Rate this question:
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- 36.
Hemoglobin unloads oxygen easier:
- A.
In a region where the oxygen concentration is very high.
- B.
As it passes through the ventricle.
- C.
Where the blood is acidic.
- D.
Because it carries only one oxygen molecule, which unloads very easily.
Correct Answer
C. Where the blood is acidic.Explanation
Hemoglobin unloads oxygen easier where the blood is acidic. This is because when the blood becomes acidic, the affinity of hemoglobin for oxygen decreases. In an acidic environment, the oxygen dissociation curve shifts to the right, causing hemoglobin to release oxygen more readily to the surrounding tissues. This is an important mechanism that allows oxygen to be delivered to tissues that are in need of it, such as during exercise or in areas of high metabolic activity.Rate this question:
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- 37.
The property of hemoglobin called co-operativity:
- A.
Helps oxygen to bind to hemoglobin quickly.
- B.
Prevents oxygen from binding to hemoglobin.
- C.
Allows hemoglobin to contain 6 subunits instead of the usual 4.
- D.
Makes hemoglobin stick to alveoli until oxygen loads.
Correct Answer
A. Helps oxygen to bind to hemoglobin quickly.Explanation
Cooperativity is a property of hemoglobin that enables it to bind oxygen molecules more readily. This occurs when one oxygen molecule binds to a subunit of hemoglobin, causing a conformational change that makes it easier for subsequent oxygen molecules to bind. Therefore, cooperativity helps oxygen to bind to hemoglobin quickly, enhancing the efficiency of oxygen uptake in the lungs and its release in the tissues.Rate this question:
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- 38.
The molecule called bicarbonate (H2CO3) forms when carbon dioxide combines with:
- A.
Water.
- B.
Hemoglobin.
- C.
Oxygen.
- D.
Another carbon dioxide molecule.
Correct Answer
A. Water.Explanation
Bicarbonate (H2CO3) is formed when carbon dioxide combines with water. This reaction occurs in the bloodstream, where carbon dioxide produced by cells diffuses into red blood cells and reacts with water to form bicarbonate ions (HCO3-) and hydrogen ions (H+). This reaction is catalyzed by an enzyme called carbonic anhydrase. Bicarbonate ions play a crucial role in maintaining the pH balance of the blood and are involved in the transport of carbon dioxide from tissues to the lungs for elimination.Rate this question:
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- 39.
The rate of breathing is controlled by:
- A.
Blood pressure on the SA node of the heart.blood pressure receptors in the diaphragm.
- B.
A respiratory center in the diaphragm.
- C.
The concentration of CO2 in the blood [more acidic]
- D.
Blood pressure receptors in the diaphragm.
Correct Answer
C. The concentration of CO2 in the blood [more acidic]Explanation
The rate of breathing is controlled by the concentration of CO2 in the blood. When the CO2 levels in the blood increase and make the blood more acidic, the body's respiratory center is stimulated to increase the rate of breathing. This helps to remove excess CO2 from the body and restore the balance of gases in the blood.Rate this question:
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- 40.
The function of alveoli of the lung is to:
- A.
Produce oxygen.
- B.
Exchange oxygen and carbon dioxide.
- C.
Produce carbon dioxide.
- D.
Expand the thoracic cavity.
Correct Answer
B. Exchange oxygen and carbon dioxide.Explanation
The alveoli of the lung are small air sacs located at the end of the bronchioles. Their main function is to facilitate the exchange of gases between the lungs and the bloodstream. Oxygen from the inhaled air diffuses across the thin walls of the alveoli into the bloodstream, while carbon dioxide, a waste product of cellular respiration, diffuses from the bloodstream into the alveoli to be exhaled. This exchange of gases allows for the oxygenation of the blood and the removal of carbon dioxide, crucial processes for maintaining proper oxygen levels in the body.Rate this question:
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- 41.
A major function of platelets is to:
- A.
Bind to histamine, thus shortening the response to a wound.
- B.
Release clotting factors.
- C.
Bind to red blood cells, creating a clot.
- D.
Release hemoglobin from red blood cells.
Correct Answer
B. Release clotting factors.Explanation
Platelets are small cell fragments that play a crucial role in blood clotting. When a blood vessel is damaged, platelets are activated and release various clotting factors, such as fibrinogen and thrombin. These factors help in the formation of a clot, which stops bleeding and promotes wound healing. Therefore, the correct answer is "release clotting factors."Rate this question:
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- 42.
The protein which forms a net-like structure to help form a clot is:
- A.
Fibrin
- B.
Thrombin
- C.
Hemoglobin
- D.
Myosin
Correct Answer
A. FibrinExplanation
Fibrin is the correct answer because it is a protein that forms a net-like structure to help form a clot. When there is an injury or damage to blood vessels, fibrinogen (a soluble protein) is converted into fibrin by the action of thrombin. Fibrin then forms a mesh-like network, trapping platelets and red blood cells to form a blood clot, which helps in stopping bleeding and promoting wound healing. Thrombin, hemoglobin, and myosin do not play a role in clot formation.Rate this question:
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- 43.
An antigen-presenting cell is a necessary part of the ________ system.
- A.
Immune
- B.
Respiratory
- C.
Digestive
- D.
None of the above are correct
Correct Answer
A. ImmuneExplanation
An antigen-presenting cell plays a crucial role in the immune system by presenting antigens to other immune cells, such as T cells. This process allows the immune system to recognize and mount a response against foreign substances, such as pathogens or cancer cells. Therefore, an antigen-presenting cell is an essential component of the immune system.Rate this question:
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- 44.
Normal control of a voluntary (striated) muscle to contract is if:
- A.
A muscle reaches the insertion point.
- B.
A tendon pulls on the muscle.
- C.
A nervous impulse causes Ca++ to leave its storage site.
- D.
The sarcomere swells up.
Correct Answer
C. A nervous impulse causes Ca++ to leave its storage site.Explanation
When a muscle receives a nervous impulse, it triggers the release of calcium ions (Ca++) from their storage site within the muscle. This release of calcium ions is a crucial step in the process of muscle contraction. The calcium ions bind to proteins within the muscle fibers, leading to a series of molecular events that ultimately result in the contraction of the muscle. Therefore, the correct answer is that a nervous impulse causes Ca++ to leave its storage site.Rate this question:
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- 45.
A characteristic of red blood cells (RBC's are shown in the illustration) is that they
- A.
Are the largest type of blood cell.
- B.
They serve to carry nutrients (i.e. glucose, amino acids) to other cells.
- C.
They are red because of hemoglobin, which is only found in red blood cells.
- D.
They are also called platelets because of their small size.
Correct Answer
C. They are red because of hemoglobin, which is only found in red blood cells.Explanation
Red blood cells are red because of hemoglobin, a protein that binds to oxygen and gives blood its red color. Hemoglobin is found only in red blood cells, not in any other type of blood cell. This is why red blood cells are responsible for transporting oxygen to the body's tissues and organs. The other options are incorrect because red blood cells are not the largest type of blood cell, they do not serve to carry nutrients to other cells, and they are not called platelets.Rate this question:
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- 46.
Cytotoxic T Cells:
- A.
Must bind to a macrophage.
- B.
Are formed from activated helper T cells.
- C.
Usually attack damaged mast cells in the non-specific defense reaction.
- D.
Are activated by chemicals from helper T cells.
Correct Answer
D. Are activated by chemicals from helper T cells.Explanation
Cytotoxic T cells are a type of immune cell that play a crucial role in the body's defense against infected or abnormal cells. They are activated by chemicals released by helper T cells, which help to coordinate and regulate the immune response. Once activated, cytotoxic T cells can directly recognize and destroy infected or abnormal cells, helping to eliminate the threat and protect the body from further harm.Rate this question:
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- 47.
Which of the following requires an antigen for it to occur?
- A.
Allergic reaction
- B.
Inflammation
- C.
Clot formation
- D.
Platelet activation.
Correct Answer
A. Allergic reactionExplanation
An allergic reaction is an immune response triggered by the presence of an antigen. When a person with allergies is exposed to an allergen, such as pollen or certain foods, their immune system recognizes it as foreign and produces antibodies to fight against it. This immune response leads to the release of histamine and other chemicals, causing symptoms like itching, swelling, and inflammation. Therefore, an allergic reaction requires an antigen to occur.Rate this question:
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- 48.
The Bohr effect deals with acidity of the blood. It is important:
- A.
In the region of the pancreas.
- B.
In the region of tissue cells.
- C.
In the blood capillaries of the lungs.
- D.
Both b and c are affected by the Bohr effect.
Correct Answer
D. Both b and c are affected by the Bohr effect.Explanation
The Bohr effect refers to the phenomenon where an increase in acidity (decrease in pH) causes a decrease in the affinity of hemoglobin for oxygen. This effect is important in both the region of tissue cells and in the blood capillaries of the lungs. In the region of tissue cells, where carbon dioxide is produced as a byproduct of cellular respiration, the increased acidity promotes the release of oxygen from hemoglobin to be used by the cells. In the blood capillaries of the lungs, where carbon dioxide is exhaled, the decreased acidity allows hemoglobin to bind more readily with oxygen for transport back to the tissues. Therefore, both b and c are affected by the Bohr effect.Rate this question:
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- 49.
The surface area of cells of the small intestine is increased by:
- A.
The flow of food past the cells.
- B.
Microvilli of the small intestine cells.
- C.
Platelets.
- D.
Increased acidity of the fluid in the small intestine.
Correct Answer
B. Microvilli of the small intestine cells.Explanation
The surface area of cells in the small intestine is increased by the presence of microvilli. Microvilli are tiny, finger-like projections that extend from the surface of the small intestine cells. These projections greatly increase the surface area available for nutrient absorption. By increasing the surface area, more nutrients can be absorbed from the food passing through the small intestine, allowing for more efficient digestion and absorption of nutrients.Rate this question:
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- 50.
The pressure induced "cannon ball-like" pressure discussed in class is associated with:
- A.
The respiratory system.
- B.
The digestive system.
- C.
The circulatory system.
- D.
Bones.
Correct Answer
B. The digestive system.Explanation
The pressure induced "cannon ball-like" pressure discussed in class is associated with the digestive system. This is because during the process of digestion, the stomach contracts and applies pressure on the food, breaking it down into smaller pieces. This pressure is similar to a cannonball being fired, hence the term "cannon ball-like" pressure.Rate this question:
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Mar 22, 2023Quiz Edited by
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May 10, 2010Quiz Created by
Funkytrunks22
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