Biology Practice Test S2 2016

Carbohydrates are organic compounds made up of carbon, oxygen, and hydrogen atoms. They are one of the main sources of energy for the body and can be found in various foods such as grains, fruits, and vegetables. The chemical formula for carbohydrates is typically represented as (CH2O)n, where "n" represents the number of carbon atoms. Therefore, the statement that carbohydrates are made out of carbon, oxygen, and hydrogen is true.

The three primary reasons for a skeleton are movement, protection, and support. The skeleton provides a framework for the body, allowing it to move and perform various activities. It also protects vital organs and delicate tissues from external forces and injuries. Additionally, the skeleton provides support to the body, maintaining its shape and structure. Style and comfort are not primary reasons for a skeleton, as they are subjective and secondary factors in comparison to the essential functions of movement, protection, and support.

The alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide occurs. Oxygen from the inhaled air enters the bloodstream through the thin walls of the alveoli, while carbon dioxide, a waste product, is removed from the bloodstream and exhaled. This process is known as gaseous exchange and is essential for respiration. Therefore, the statement that alveoli is where gaseous exchange takes place is true.

The statement is true because the proper name for the food pipe is indeed the esophagus, or oesophagus in British English. The esophagus is a muscular tube that connects the throat to the stomach, allowing food and liquids to pass from the mouth to the stomach for digestion.

The small intestine is responsible for absorbing soluble food molecules from the digestive system and releasing them into the blood. It is a long, narrow tube located between the stomach and the large intestine. The inner lining of the small intestine is covered in tiny finger-like projections called villi, which increase the surface area for absorption. This allows for efficient absorption of nutrients such as sugars, amino acids, and fatty acids into the bloodstream, where they can be transported to cells throughout the body for energy and growth.

The statement is true because a normal blood pressure reading is typically defined as having a systolic pressure of 120 mmHg (millimeters of mercury) and a diastolic pressure of 80 mmHg. Systolic pressure represents the force of blood against artery walls when the heart contracts, while diastolic pressure represents the force when the heart is at rest between beats. These values are considered within the normal range and indicate a healthy blood pressure level.

Iodine is used to test for starch. When iodine comes into contact with starch, it forms a blue-black color. This reaction occurs due to the formation of a complex between iodine molecules and the helical structure of starch molecules. Therefore, by using iodine solution, we can easily identify the presence of starch in a substance.

The human heart is a muscular organ that pumps blood throughout the body. It is divided into four chambers: two atria and two ventricles. The atria receive blood from the body and lungs, while the ventricles pump blood out to the rest of the body. This division of chambers allows for efficient circulation of oxygenated and deoxygenated blood, ensuring that the body receives the necessary nutrients and oxygen. Therefore, the correct answer is 4.

Biuret solution is used to test for the presence of protein. When biuret solution is added to a sample containing protein, it reacts with the peptide bonds in the protein molecules, forming a purple color complex. This color change indicates the presence of protein in the solution. Benedict's solution is used to test for reducing sugars, while iodine solution is used to test for the presence of starch.

The correct answer is Benedict. Benedict's solution is used to test for the presence of glucose. It is a blue-colored solution that changes to green, yellow, orange, or brick-red in the presence of glucose, indicating a positive result. This solution is commonly used in laboratory tests and diagnostic procedures to detect the presence of reducing sugars, including glucose, in various biological samples.

The liver is responsible for producing bile. Bile is a greenish-yellow fluid that aids in the digestion and absorption of fats in the small intestine. It is produced by the liver cells and stored in the gallbladder until it is needed for digestion. Bile contains bile salts, which help break down fats into smaller droplets, making it easier for enzymes to break them down further. Additionally, bile helps in the elimination of waste products, such as bilirubin, from the body.

Fats are actually made up of carbon, hydrogen, and oxygen, but not nitrogen. Therefore, the statement is false.

Proteins are organic compounds made up of carbon, oxygen, nitrogen, and hydrogen atoms. These elements combine in various ways to form amino acids, which are the building blocks of proteins. Therefore, it is correct to say that proteins are made out of carbon, oxygen, nitrogen, and hydrogen.

The bottom two chambers of the heart are called ventricles. The heart is divided into four chambers: two atria (upper chambers) and two ventricles (lower chambers). The ventricles are responsible for pumping blood out of the heart and into the rest of the body. They have thicker walls compared to the atria, as they need to generate more force to push the blood through the circulatory system.

The correct answer is Natural openings, Mouth, and inhalation. Diseases can enter the body through natural openings such as the nose, ears, and genitals. The mouth is another common entry point for diseases, as it is where we consume food and drink. Inhalation refers to breathing in pathogens or harmful substances, which can then enter the body and cause diseases.

The gall bladder stores bile, which is then released through the bile duct. Bile is a digestive fluid produced by the liver and stored in the gall bladder. It plays a crucial role in the digestion and absorption of fats in the small intestine. When food containing fats enters the small intestine, the gall bladder contracts and releases bile into the bile duct. From there, it travels to the small intestine to aid in the breakdown and absorption of fats.

The correct body temperature for the body is 37 degrees Celsius. This is considered the normal body temperature for a healthy adult. It is important for the body to maintain this temperature in order for its physiological processes to function properly. Deviations from this temperature can indicate an underlying health issue.

The acid present in the stomach is hydrochloric acid. This acid is secreted by the cells lining the stomach walls and plays a crucial role in the digestion of food. It helps in breaking down proteins, activating enzymes, and killing bacteria that may enter the stomach through ingested food. Hydrochloric acid also creates an acidic environment in the stomach, which is necessary for the proper functioning of digestive enzymes.

Gaseous exchange is the process in which oxygen and CO2 move between the blood and lungs. During respiration, oxygen is taken in by the lungs and transported to the bloodstream, where it binds to hemoglobin in red blood cells. At the same time, carbon dioxide, a waste product of cellular respiration, is released from the blood into the lungs to be exhaled. This exchange occurs across the thin walls of the capillaries in the lungs, allowing for the oxygenation of the blood and the removal of carbon dioxide.

The body uses various physical defenses to protect against diseases. Hair acts as a barrier, preventing pathogens from entering the body through the skin. The skin itself acts as a protective layer, preventing the entry of harmful microorganisms. Ear wax traps and prevents the growth of bacteria and fungi in the ear canal. Stomach acid kills many pathogens that are ingested through food or drink. Mucus traps and removes pathogens from the respiratory system. Tears contain enzymes and antibodies that help to fight off infections in the eyes. Saliva contains antimicrobial compounds that help to prevent the growth of bacteria in the mouth.

The suspected glucose solution with Benedict's solution should be left in the water bath at a temperature of 85 degrees Celsius.

The correct answer is "atrium" because the heart is divided into four chambers: two atria and two ventricles. The atria are the top chambers, with the left atrium and right atrium. The atria receive blood returning to the heart and then pump it into the ventricles for further circulation.

Phagocytes are a type of white blood cells that play a crucial role in the immune system. They are responsible for engulfing and destroying harmful bacteria, viruses, and other foreign substances in the body. By doing so, phagocytes help in preventing infections and maintaining overall health.

During gaseous exchange, alveoli are assisted by a vast network of blood capillaries. Capillaries are tiny blood vessels with thin walls that are located close to the alveoli in the lungs. The close proximity of capillaries to alveoli allows for efficient exchange of gases between the air in the alveoli and the blood in the capillaries. Oxygen from the air diffuses into the capillaries and binds to red blood cells, while carbon dioxide, a waste product, diffuses out of the capillaries into the alveoli to be exhaled. This network of capillaries ensures that oxygen is delivered to the body's tissues and carbon dioxide is removed efficiently.

Lymphocytes are a specific type of white blood cells that play a crucial role in the immune system. They are responsible for recognizing and attacking foreign substances, such as bacteria, viruses, and other pathogens. Lymphocytes are produced in the bone marrow and can be found in the blood, lymph nodes, and lymphatic tissues. They are divided into three main types: B cells, T cells, and natural killer cells, each with its own unique function in defending the body against infections and diseases.