1.
What is the outer layer of the kidney?
Correct Answer
B. Cortex
Explanation
The correct answer is cortex. The cortex is the outer layer of the kidney. It contains the glomeruli, which are responsible for filtering the blood and producing urine. The cortex also contains the renal tubules, which reabsorb nutrients and water from the filtrate. The medulla, on the other hand, is the inner part of the kidney and contains the renal pyramids. The nephron is the functional unit of the kidney, responsible for filtering and regulating the composition of urine. However, in this question, the outer layer of the kidney is specifically being referred to, which is the cortex.
2.
What is the middle layer of the kidney?
Correct Answer
C. Renal Medulla
Explanation
The middle layer of the kidney is called the renal medulla. It is located between the outer layer called the cortex and the innermost part called the pyramids. The medulla contains structures called renal pyramids, which are responsible for collecting urine and transporting it to the renal pelvis. Additionally, the medulla plays a crucial role in regulating the concentration of urine and maintaining the balance of water and electrolytes in the body.
3.
Deficiency of which vitamin can lead to irritability, loss of appetite, and beriberi?
Correct Answer
C. Vitamin B1
Explanation
Deficiency of Vitamin B1 can lead to irritability, loss of appetite, and beriberi. Beriberi is a condition characterized by muscle weakness, nerve damage, and heart problems. Vitamin B1, also known as thiamine, is essential for the proper functioning of the nervous system and the metabolism of carbohydrates. It is commonly found in foods such as whole grains, legumes, and nuts.
4.
What are the plasma-soluble substances that are secreted by gram-positive bacteria called?
Correct Answer
B. Exotoxin
Explanation
Exotoxins are soluble substances that are secreted by gram-positive bacteria. These toxins are released into the surrounding environment by the bacteria and can cause damage to host cells or tissues. Unlike endotoxins, which are part of the bacterial cell wall and are released when the bacteria die, exotoxins are actively secreted by living bacteria. Therefore, the correct answer is exotoxin.
5.
What are the soluble proteins secreted by bacteria that enter host cells called?
Correct Answer
C. Effector Proteins
Explanation
The soluble proteins secreted by bacteria that enter host cells are commonly referred to as "effector proteins." These proteins are part of the bacterial type III secretion system, which allows bacteria to inject these proteins directly into the host cell. Effector proteins play a crucial role in manipulating host cell processes to benefit the invading bacteria, such as suppressing immune responses or altering cellular signaling pathways. This ability to directly modulate host cell functions is a key virulence mechanism employed by many pathogenic bacteria.
6.
What are the components of the Gram-negative bacterial cell wall called?
Correct Answer
A. Endotoxins
Explanation
Gram-negative bacterial cell walls contain lipopolysaccharides (LPS), which are known as endotoxins. These endotoxins are released when the bacterial cell wall is damaged or destroyed, and they can cause a strong immune response in the host organism. Exotoxins, on the other hand, are toxic substances secreted by bacteria that can cause damage to the host even in the absence of the bacteria themselves. Therefore, the correct answer is endotoxins.
7.
What causes direct damage to the cells?
Correct Answer
A. Cytotoxins
Explanation
Cytotoxins directly damage cells. They are substances that are toxic to cells and can cause cell death or dysfunction. These toxins can disrupt cellular processes, leading to tissue damage and organ dysfunction. They can also trigger an immune response, causing inflammation and further damage to surrounding cells. Overall, cytotoxins have a direct harmful effect on cells and are responsible for causing cellular damage.
8.
What causes intestinal symptoms?
Correct Answer
C. Enterotoxins
Explanation
Enterotoxins cause intestinal symptoms. These toxins are produced by certain bacteria and are responsible for causing gastrointestinal issues such as diarrhea, vomiting, and abdominal pain. Enterotoxins work by disrupting the normal functioning of the intestinal cells, leading to increased fluid secretion and decreased absorption, resulting in the characteristic symptoms. These toxins are commonly produced by bacteria like Escherichia coli, Vibrio cholerae, and Staphylococcus aureus, among others. Understanding the role of enterotoxins is crucial in diagnosing and treating bacterial infections that affect the gastrointestinal system.
9.
What is an organism with chloroplast in its cell?
Correct Answer
B. Autotroph
Explanation
An organism with chloroplast in its cell is probably an autotroph. Autotrophs are capable of producing their own food through photosynthesis, which requires chloroplasts. Chloroplasts contain chlorophyll, a pigment that captures sunlight and converts it into energy for the synthesis of organic compounds. This process allows autotrophs to convert inorganic substances, such as carbon dioxide and water, into organic molecules like glucose. Therefore, an organism with chloroplasts is likely to be an autotroph, capable of producing its own food.
10.
What property of water allows someone to fill a glass slightly above the rim without the water flowing over?
Correct Answer
D. Surface tension
Explanation
Surface tension is the property of water that allows someone to fill a glass slightly above the rim without the water flowing over. Surface tension is caused by the cohesive forces between water molecules, which create a "skin" or "film" on the surface of the water. This cohesive force creates a strong bond between water molecules at the surface, preventing the water from easily flowing over the rim of the glass.
11.
What are the spaces between neurons?
Correct Answer
A. Synapses
Explanation
Synapses are the correct answer because they refer to the spaces between neurons where communication occurs. Neurons transmit signals across these small gaps, allowing information to be transferred from one neuron to another. Synapses play a crucial role in the functioning of the nervous system, enabling the transmission of electrical and chemical signals that are essential for processes such as learning, memory, and coordination.
12.
Which group of chemicals is not normally found in most living things?
Correct Answer
C. Silicates
Explanation
Silicates are not normally found in most living things. Silicates are compounds that contain silicon and oxygen and are commonly found in minerals such as quartz and feldspar. While silicon is an essential element for some organisms, it is not typically found in the form of silicates within living organisms. Instead, living things primarily consist of carbohydrates, proteins, and nucleic acids, which are the essential building blocks for various biological processes.
13.
With what system is the alimentary canal associated?
Correct Answer
B. Digestive system
Explanation
The alimentary canal refers to the entire pathway through which food passes in the body, including the mouth, esophagus, stomach, small intestine, and large intestine. It is responsible for the digestion and absorption of nutrients. The digestive system is closely associated with the alimentary canal as it includes all the organs and structures involved in the process of digestion, such as the salivary glands, liver, gallbladder, and pancreas. Therefore, the correct answer is digestive system.
14.
What purpose do the numerous villi in the small intestine serve?
Correct Answer
D. Provide greater surface for absorption.
Explanation
The numerous villi in the small intestine provide a greater surface area for absorption. Villi are small finger-like projections that line the walls of the small intestine. Their purpose is to increase the surface area available for the absorption of nutrients from digested food. This increased surface area allows for a more efficient absorption of nutrients into the bloodstream, ensuring that the body receives the necessary energy and nutrients from the food we consume.
15.
What is the bending of light called when it passes obliquely from air to water?
Correct Answer
A. Refraction
Explanation
When light passes obliquely from air to water, it changes direction due to the change in its speed. This phenomenon is called refraction. Refraction occurs because light travels at different speeds in different mediums, and when it enters a medium with a different optical density, it bends. In this case, as light enters water from air, it slows down and changes direction, causing the bending effect. Diffraction refers to the spreading out of light waves when they encounter an obstacle or pass through a narrow opening. Reflection is the bouncing back of light waves when they hit a surface. Dispersion refers to the separation of white light into its constituent colors.
16.
Which of the following organelles is not involved in protein synthesis?
Correct Answer
B. Mitochondrion
Explanation
Mitochondria, while they do have their own ribosomes and can synthesize some proteins, these are mostly mitochondrial-specific proteins. They are not traditionally involved in the general cellular protein synthesis pathway that uses mRNA produced by the nucleus. Therefore, among the options given, the mitochondrion is the correct answer as it is least involved in the broader context of cellular protein synthesis described here.
17.
What must proteins be changed to in order to be absorbed by cells?
Correct Answer
A. Amino acids
Explanation
Proteins are large molecules made up of amino acids. In order for cells to absorb and utilize proteins, they must be broken down into their individual amino acid components. This process is carried out by enzymes in the digestive system. Once proteins are broken down into amino acids, they can be transported into cells and used for various cellular functions such as building new proteins, repairing damaged tissues, and providing energy. Therefore, the correct answer is amino acids.
18.
What is a neuron called that transmits impulses from the receptors to the spinal cord?
Correct Answer
D. Sensory neuron
Explanation
A sensory neuron is responsible for transmitting impulses from the receptors to the spinal cord. These neurons are specialized to detect and transmit sensory information from various parts of the body to the central nervous system. They play a crucial role in allowing us to perceive and respond to different stimuli such as touch, temperature, pain, and pressure. Sensory neurons are essential for our ability to sense and interact with the world around us.
19.
Which group of organisms helps prevent the accumulation of organic waste in nature?
Correct Answer
C. Bacteria
Explanation
Bacteria help prevent the accumulation of organic waste in nature. Bacteria play a crucial role in the decomposition process, breaking down organic matter and recycling nutrients back into the ecosystem. They are responsible for breaking down dead plants, animals, and other organic materials, converting them into simpler compounds that can be used by other organisms. Without bacteria, organic waste would accumulate, leading to imbalances in ecosystems and nutrient deficiencies. Therefore, bacteria are essential for maintaining a healthy and sustainable environment.
20.
How is the sound perceived when the eardrum is made to vibrate more rapidly?
Correct Answer
C. Higher in pitch
Explanation
When the eardrum vibrates more rapidly, it means that the sound waves have a higher frequency. The frequency of a sound wave determines its pitch. Therefore, when the eardrum vibrates more rapidly, the sound is perceived as higher in pitch.
21.
In a field of pure white asters, a grower noticed a single blue aster. How could the grower test whether this change affected the gamete-producing cells of the plant?
Correct Answer
A. Self pollinate the flower and plant the resulting seeds.
Explanation
The grower can test whether the change affected the gamete-producing cells of the plant by self-pollinating the flower and planting the resulting seeds. If the blue color trait is inherited in the offspring, it indicates that the change affected the gamete-producing cells and is heritable. This method allows for the observation of the trait in subsequent generations, providing evidence of its presence in the gametes.
22.
A human egg will develop into a female if it is fertilized by a sperm containing which chromosome?
Correct Answer
A. X chromosome
Explanation
When a human egg is fertilized by a sperm containing an X chromosome, it will develop into a female. This is because females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The presence of the X chromosome determines the development of female reproductive organs.
23.
In a food chain involving grass, grasshoppers, birds, and mammals, the original source of energy is:
Correct Answer
B. Sunlight
Explanation
In a food chain involving grass, grasshoppers, birds, and mammals, the original source of energy is sunlight. Sunlight is essential for photosynthesis, a process in which plants, such as grass, convert sunlight into glucose, a form of chemical energy. This glucose is then consumed by grasshoppers, which are in turn consumed by birds, and eventually by mammals. Thus, sunlight is the initial source of energy that fuels the entire food chain.
24.
Which of these are good sources of protein?
Correct Answer
A. Nuts
Explanation
Nuts are a good source of protein because they contain a significant amount of this macronutrient. They are particularly rich in plant-based proteins, such as almonds, cashews, and peanuts. These proteins are essential for building and repairing tissues, supporting immune function, and producing enzymes and hormones. Nuts also provide other beneficial nutrients like healthy fats, fiber, vitamins, and minerals, making them a nutritious choice for protein intake.
25.
A reading on the Celsius scale is 5, a reading on the Fahrenheit would be:
Correct Answer
C. 41
Explanation
To convert a temperature from Celsius (°C) to Fahrenheit (°F), you can use the following formula:
°F = (°C × 9/5) + 32
In this case, if the Celsius reading is 5:
°F = (5 × 9/5) + 32
°F = (9) + 32
°F = 41
So, a reading of 5 degrees Celsius is equivalent to 41 degrees Fahrenheit.
26.
Which of the following is the primary function of the lymphatic system?
Correct Answer
B. Protecting the body against infections.
Explanation
The lymphatic system plays a key role in the immune system by defending the body against infections. It consists of lymph nodes, lymphatic vessels, and lymph, a fluid that carries white blood cells to fight infections. The system filters pathogens, toxins, and waste products from the blood, ensuring that harmful substances do not spread throughout the body. Additionally, it transports fats from the digestive system and is involved in maintaining fluid balance. Disorders of the lymphatic system, such as lymphedema or lymphoma, can compromise immune function.
27.
Which of these nitrogenous bases may be found in RNA but not DNA?
Correct Answer
A. Uracil
Explanation
Uracil is the correct answer because it is a nitrogenous base that is found in RNA but not in DNA. RNA contains uracil instead of thymine, which is found in DNA. Uracil pairs with adenine in RNA, while thymine pairs with adenine in DNA. Therefore, uracil is unique to RNA and is not present in DNA. This difference in nitrogenous bases is one of the key distinctions between RNA and DNA, contributing to their different functions within the cell. Understanding this distinction is crucial for comprehending the processes of transcription and translation in molecular biology.
28.
A substance with a ph of 8 is a:
Correct Answer
D. Weak base
Explanation
A substance with a pH of 8 indicates that it is slightly basic or alkaline. pH values range from 0 to 14, with 7 being neutral. As the pH increases above 7, the substance becomes more basic. Therefore, a substance with a pH of 8 would be considered a weak base. A pH of 8 means that the substance has a lower concentration of hydrogen ions compared to a stronger base with a higher pH value. This makes it less reactive and less likely to cause irritation or damage.
29.
Binary fission in paramecium and budding in yeast cells are examples of:
Correct Answer
A. Asexual reproduction
Explanation
Binary fission in paramecia and budding in yeast cells are both examples of asexual reproduction. Asexual reproduction involves the production of offspring without the involvement of gametes or the combination of genetic material from two parents. In binary fission, the parent organism divides into two equal-sized daughter cells, each with the same genetic material as the parent. Similarly, in budding, a small bud or outgrowth forms on the parent organism and eventually detaches to become a new individual. Both processes result in the production of genetically identical offspring, making them examples of asexual reproduction.
30.
Which of these substances forms an alkaline solution in water?
Correct Answer
A. Mg(OH)2
Explanation
Mg(OH)2, also known as magnesium hydroxide, forms an alkaline solution in water. When Mg(OH)2 is dissolved in water, it dissociates into magnesium ions (Mg2+) and hydroxide ions (OH-). The presence of hydroxide ions increases the pH of the solution, making it alkaline. This is because hydroxide ions are a base and can accept protons (H+) from water molecules, resulting in the formation of OH- ions. Therefore, Mg(OH)2 is the only substance among the given options that forms an alkaline solution in water.
31.
Certain seaweeds accumulate in iodine in a concentration as much as a million times greater than the surrounding ocean. How must this intake be accomplished?
Correct Answer
C. Active transport
Explanation
Certain seaweeds accumulate iodine in a concentration as much as a million times greater than the surrounding ocean. This indicates that the intake of iodine by the seaweeds must be accomplished through active transport. Active transport is a process that requires energy and moves substances against their concentration gradient, from an area of low concentration to an area of high concentration. Since the concentration of iodine in the seaweeds is much higher than the surrounding ocean, it suggests that the seaweeds actively transport iodine into their cells, using energy to maintain this high concentration.
32.
Hydrogen can be prepared in the lab by combining Zn and HCl; the resulting reaction is metallic zinc:
Correct Answer
C. Replaces the combined hydrogen in the acid.
Explanation
In the lab, hydrogen can be prepared by combining zinc (Zn) and hydrochloric acid (HCl). In this reaction, the metallic zinc replaces the combined hydrogen in the acid. This means that the zinc atoms take the place of the hydrogen atoms in the hydrochloric acid, resulting in the formation of hydrogen gas. The zinc atoms react with the acid, causing a displacement of the hydrogen atoms and ultimately leading to the production of hydrogen gas.
33.
Which of the following organisms has a nutritive process most similar to that of animals?
Correct Answer
D. Bread mold
Explanation
Bread mold has a nutritive process most similar to that of animals because it is a type of fungus that obtains its nutrients by breaking down organic matter through the process of decomposition. Similarly, animals obtain their nutrients by consuming other organisms or organic matter. Seaweed, oak tree, and grass, on the other hand, are all photosynthetic organisms that obtain their nutrients through the process of photosynthesis, which is different from the nutritive process of animals and bread mold.
34.
The solubility of a solid in a liquid generally increases with:
Correct Answer
A. Increase in temperature
Explanation
The solubility of a solid in a liquid generally increases with an increase in temperature because higher temperatures provide more energy for the particles in the solid to break apart and mix with the liquid. This increased kinetic energy helps overcome the attractive forces between the solid particles, allowing them to dissolve more easily. Therefore, as the temperature rises, more solid can dissolve in the liquid, leading to an increase in solubility.
35.
Which of these substances has the highest boiling point?
Correct Answer
D. Glycerol
Explanation
Glycerol has the highest boiling point among the substances listed. This is due to its molecular structure, which allows for extensive hydrogen bonding, leading to a higher boiling point compared to ether, ethanol, and water. Additionally, glycerol has three hydroxyl groups that can form hydrogen bonds with surrounding molecules, further increasing its boiling point. This strong intermolecular attraction results in glycerol requiring more energy to break apart and transition into a gas phase.
36.
In humans, if the diaphragm is pushed upward, there is a decrease in chest volume. The decrease is followed by:
Correct Answer
B. Increase in pressure in the chest cavity and exhalation.
Explanation
When the diaphragm is pushed upward in humans, it decreases the volume of the chest cavity. This decrease in volume leads to an increase in pressure in the chest cavity. As a result, the air is forced out of the lungs, causing exhalation. Therefore, the correct answer is an increase in pressure in the chest cavity and exhalation. The diaphragm plays a crucial role in the process of breathing by creating changes in pressure within the chest cavity. This mechanism allows for the exchange of gases necessary for respiration to occur efficiently.
37.
Which of these biological processes includes the other three?
Correct Answer
A. Cell respiration
Explanation
Cell respiration is the correct answer because it encompasses the other three processes mentioned. The Krebs cycle and electron transport chain are both part of cell respiration, which is the process by which cells convert glucose into energy. Anaerobic splitting of glucose is also a part of cell respiration, specifically referring to the breakdown of glucose in the absence of oxygen. Therefore, cell respiration includes all of these processes within its overall mechanism.
38.
A 5-year-old and her father each lifted identical chairs from the floor to a tabletop. Which person did the most work?
Correct Answer
C. Both did equal amount of work.
39.
An excess of which of these ions tends to make a solution acidic:
Correct Answer
C. Hydronium
Explanation
An excess of hydronium ions tends to make a solution acidic because hydronium ions are formed when water molecules accept protons (H+) from other substances. In an acidic solution, there is a higher concentration of hydronium ions compared to hydroxide ions, resulting in a lower pH value. The presence of hydronium ions indicates the presence of an acidic solution.
40.
In the classification of two organisms, which of the following is the best evidence of a close relationship?
Correct Answer
B. Similar sequences of amino acids in their proteins.
Explanation
Similar sequence of amino acids in their proteins is the best evidence of a close relationship between two organisms. This is because the sequence of amino acids in proteins is determined by the genetic code, which is highly conserved among related species. Therefore, if two organisms have a high degree of similarity in the sequence of amino acids in their proteins, it suggests that they share a common ancestor and have a close evolutionary relationship.
41.
What is the primary purpose of a Foley catheter?
Correct Answer
C. Draining urine from the bladder.
Explanation
A Foley catheter is a medical device used to drain urine from the bladder. It is typically inserted through the urethra and into the bladder, where it allows for continuous drainage of urine. This type of catheter is commonly used in patients who are unable to urinate on their own due to conditions such as urinary retention, surgery, or severe illness. The catheter is often used in hospitalized patients for short-term or long-term management of urinary function.
42.
Suppose cube 'a' is 10 cm along each edge and cube 'b' is 5 cm along each edge. What is the relationship of the volume of cube 'a' to that of cube 'b'?
Correct Answer
D. Cube a has 8x the volume of cube b
Explanation
Cube A has 8 times the volume of Cube B because the volume of a cube is calculated by multiplying the length of one side by itself three times. Cube A has sides that are twice as long as Cube B, so when we calculate the volume of Cube A (10 cm x 10 cm x 10 cm), it is 1000 cubic cm. The volume of Cube B (5 cm x 5 cm x 5 cm) is 125 cubic cm. Therefore, Cube A has 8 times the volume of Cube B (1000 cubic cm ÷ 125 cubic cm = 8).
43.
The organ in the human female that develops to nourish the embryo is called
Correct Answer
D. Placenta
Explanation
The organ in the human female that develops to nourish the embryo is called the placenta. The placenta is a temporary organ that forms during pregnancy and connects the developing fetus to the uterine wall. It provides oxygen, nutrients, and removes waste products from the baby's blood. The placenta also produces hormones that are essential for maintaining pregnancy.
44.
Which of these substances is a product of cellular respiration in animals?
Correct Answer
A. ATP
Explanation
ATP (adenosine triphosphate) is a product of cellular respiration in animals. During cellular respiration, glucose is broken down in the presence of oxygen to produce ATP, which is the main energy currency of cells. ATP is used by cells for various energy-requiring processes, such as muscle contraction, active transport, and synthesis of molecules. Therefore, ATP is the correct answer as it is directly involved in the energy production process of cellular respiration in animals.
45.
What would be a likely result if all the bees and butterflies in an area were destroyed?
Correct Answer
D. Fewer plant seeds would be produced.
Explanation
If all the bees and butterflies in an area were destroyed, there would be fewer plant seeds produced. Bees and butterflies are important pollinators that help in the process of pollination, which is crucial for plant reproduction. They transfer pollen from the male parts of flowers to the female parts, leading to seed production. Without bees and butterflies, the pollination process would be significantly hindered, resulting in a decrease in plant seed production.
46.
The tiny projections in the small intestine adapted for absorption are called:
Correct Answer
B. Villi
Explanation
The tiny projections in the small intestine that are adapted for absorption are called villi. These finger-like structures increase the surface area of the small intestine, allowing for more efficient absorption of nutrients from digested food. The villi are covered in microvilli, which further increase the surface area and enhance absorption. This adaptation is essential for the absorption of nutrients such as carbohydrates, proteins, and fats into the bloodstream for distribution throughout the body.
47.
A student wants to grow a bacterial culture. Which of these environments is best suited for growing most kinds of bacteria?
Correct Answer
C. An incubator at 37 degrees Celsius
Explanation
Bacteria generally thrive in warm temperatures, and an incubator set at 37 degrees Celsius provides the ideal conditions for their growth. This temperature closely resembles the human body temperature, which is why it is often used to culture bacteria in laboratory settings. The other options, such as a lighted window at 72 degrees Fahrenheit, a refrigerator at 45 degrees Fahrenheit, and a freezer at 10 degrees Fahrenheit, are either too cold or too variable in temperature to support optimal bacterial growth.
48.
A closed container of hydrogen gas is warmed from 20c to 25c. If the volume remains the same, what will happen to the pressure in the container?
Correct Answer
D. It will increase.
Explanation
When a closed container of gas is warmed, the molecules of the gas gain kinetic energy and move faster. This increased movement leads to more frequent collisions between the gas molecules and the walls of the container. As a result, the pressure exerted by the gas on the container increases. Therefore, when the container of hydrogen gas is warmed from 20°C to 25°C, and the volume remains the same, the pressure in the container will increase.
49.
Most of the work done by the human kidney occurs in the:
Correct Answer
A. Nephron
Explanation
The correct answer is nephron. The nephron is the functional unit of the kidney and is responsible for filtering waste products from the blood, reabsorbing essential substances, and maintaining the balance of fluids and electrolytes in the body. It consists of several structures, including the glomerulus, proximal tubule, loop of Henle, and distal tubule. These structures work together to regulate blood pressure, produce urine, and maintain homeostasis in the body.
50.
Equal armed balance is balanced when 20 washers are on one side, and 10 bolts are on the other. Four bolts are added to one side. How many washers must be added to the next side to maintain balance?
Correct Answer
B. 8
Explanation
To maintain balance in equal armed balance, the weight on both sides should be equal. Initially, there are 20 washers on one side and 10 bolts on the other side. If four bolts are added to one side, the weight on that side will increase. To maintain balance, an equal number of washers should be added to the other side. Since the weight of one bolt is equal to the weight of two washers, adding four bolts is equivalent to adding eight washers. Therefore, to maintain balance, eight washers must be added to the next side.