Human Biology Practice Quiz: Discover Your Inner Biologist
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Our Human Biology Practice Quiz Test is designed to assess your understanding of the fascinating world of human biology. This quiz covers a wide range of topics, from the basics of cellular structure to the complexities of the human organ systems. Test your knowledge and enhance your grasp of key concepts related to anatomy, physiology, genetics, and more. This quiz offers a valuable learning experience, allowing you to identify areas where you excel and those that need further study.
Each question is crafted to challenge your understanding, making this a perfect resource for students and biology enthusiasts alike. Read moreLearn about the intricate details of human biology and challenge yourself with this comprehensive practice quiz. Good luck, and let's explore the wonders of the human body! Take the human biology test today and see how you fare in the captivating study of life!
Human Biology Practice Questions and Answers
- 1.
If the neutrons in the nucleus of an atom are more numerous than the number of protons in the nucleus, then:
- A.
The atom is considered to be an ion.
- B.
The nucleus is not possible.
- C.
The atomic weight will always be the same as the number of electrons in the atom.
- D.
The atom has extra electrons.
- E.
None of the above is true.
Correct Answer
E. None of the above is true.Explanation
If the neutrons in a nucleus of an atom are more numerous than the number of protons in the nucleus, it does not necessarily mean that the atom is considered to be an ion. An ion is formed when an atom gains or loses electrons, not due to the number of neutrons. Additionally, the statement that the nucleus is not possible is incorrect as neutrons are essential components of the nucleus. The atomic weight is determined by the combined mass of protons and neutrons, not the number of electrons. Lastly, the statement that the atom has extra electrons is also not true as the number of electrons in an atom is determined by the number of protons. Therefore, the correct answer is that none of the above statements are true.Rate this question:
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- 2.
In the human body, the food we eat is ultimately stored in what form of energy?
- A.
ATP
- B.
Carbon Dioxide
- C.
Fructose
- D.
Heat
- E.
Oxygen
Correct Answer
A. ATPExplanation
ATP (adenosine triphosphate) is the correct answer because it is the primary form of energy used by cells in the human body. When we eat food, it is broken down into smaller molecules, such as glucose, which are then converted into ATP through cellular respiration. ATP is used by cells to carry out various functions, including muscle contractions, nerve impulses, and synthesis of molecules. It acts as a "currency" for energy transfer within cells, providing the necessary energy for cellular processes to occur. Therefore, ATP is the form in which energy is stored and utilized in the human body.Rate this question:
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- 3.
What is a non-polar molecule?
- A.
The atoms bond by neutrons instead of electrons.
- B.
Only those which contain hydrogen.
- C.
Water.
- D.
The atoms share the electrons equally.
- E.
Ions that become neutral from bonding.
Correct Answer
D. The atoms share the electrons equally.Explanation
A non-polar molecule refers to a molecule in which the electrons are shared equally between the atoms. This means that there is no separation of charge within the molecule, resulting in a balanced distribution of electrons. In contrast, polar molecules have an uneven distribution of electrons, leading to partial positive and negative charges. Therefore, the correct answer is that a non-polar molecule is one in which the atoms share the electrons equally.Rate this question:
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- 4.
Which organelle is the site of most ATP formation in the cell?
- A.
Mitochondrion
- B.
Nucleus
- C.
Ribosomes
- D.
Smooth Endoplasmic Reticulum
- E.
None of the above
Correct Answer
A. MitochondrionExplanation
The mitochondrion is the site of most ATP formation in the cell. This organelle is often referred to as the "powerhouse" of the cell because it is responsible for producing the majority of the cell's energy in the form of ATP (adenosine triphosphate). Through a process called cellular respiration, the mitochondria use oxygen and nutrients to generate ATP, which is then used by the cell for various energy-requiring processes. The other options listed (nucleus, ribosomes, smooth endoplasmic reticulum) are not directly involved in ATP production.Rate this question:
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- 5.
The name of the process shown here is:
- A.
Active Transport
- B.
Condensation Reactions
- C.
DNA Synthesis
- D.
Facilitated Diffusion
- E.
Osmosis
Correct Answer
A. Active TransportExplanation
Active transport is the process shown here because it involves the movement of molecules or ions against their concentration gradient, from an area of lower concentration to an area of higher concentration. This process requires the use of energy in the form of ATP to transport the molecules or ions across the cell membrane. Unlike passive transport mechanisms such as facilitated diffusion or osmosis, active transport requires energy expenditure and is therefore the correct answer.Rate this question:
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- 6.
This is found in the membrane and forms ATP.
- A.
ATP Synthase
- B.
Glycolysis of cellular respiration
- C.
Krebs cycle of cellular respiration
- D.
Protein complexes which pass electrons
- E.
None of the above
Correct Answer
A. ATP SynthaseExplanation
ATP Synthase is the correct answer because it is an enzyme found in the membrane that is responsible for synthesizing ATP. It uses the energy from a proton gradient across the membrane to convert ADP and inorganic phosphate into ATP. This process is known as oxidative phosphorylation and is a crucial step in cellular respiration, where ATP is produced as the main energy currency of the cell. The other options, glycolysis, Krebs cycle, and protein complexes that pass electrons, are all involved in cellular respiration but do not directly form ATP.Rate this question:
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- 7.
Which of the following is a characteristic of living organisms?
- A.
Living organisms respond to the environment.
- B.
Living organisms are composed of one or more cells.
- C.
Living organisms use energy.
- D.
Living organisms reproduce.
- E.
All of the above are characteristics of living things.
Correct Answer
E. All of the above are characteristics of living things.Explanation
All of the options listed in the question are characteristics of living organisms. Living organisms respond to the environment by adapting and changing their behavior or physiology. They are composed of one or more cells, which are the basic building blocks of life. Living organisms use energy to carry out their life processes, such as growth, movement, and reproduction. Speaking of reproduction, living organisms have the ability to produce offspring and pass on their genetic information to the next generation. Therefore, all of these characteristics are true for living things.Rate this question:
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- 8.
Which bond is the weakest?
- A.
Covalent
- B.
Hydrogen
- C.
Ionic
- D.
Peptide
- E.
Both C and D are the least strong (weakest)
Correct Answer
B. HydrogenExplanation
Hydrogen bonds are the weakest type of bond among the options given. While covalent bonds involve the sharing of electrons between atoms, hydrogen bonds are formed when a hydrogen atom is attracted to a highly electronegative atom, such as oxygen or nitrogen. This attraction is relatively weak compared to the strong electrostatic forces present in ionic bonds, which involve the complete transfer of electrons between atoms. Peptide bonds, on the other hand, are a type of covalent bond specifically found in proteins and are stronger than hydrogen bonds. Therefore, the correct answer is hydrogen.Rate this question:
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- 9.
The last heart chamber to which blood flows before going to the body is the:
- A.
Left atrium
- B.
Left ventricle
- C.
Aorta
- D.
Right ventricle
- E.
Right atrium
Correct Answer
B. Left ventricleExplanation
The left ventricle is the last heart chamber to which blood flows before going to the body. It receives oxygenated blood from the left atrium and then pumps it out through the aorta, which is the main artery that carries oxygen-rich blood to the rest of the body. The left ventricle is responsible for generating the force needed to propel the blood throughout the body, making it an essential part of the circulatory system.Rate this question:
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- 10.
The ______ causes contractions of the ventricles of the heart.
- A.
Vena cava
- B.
AB Node
- C.
AV Node
- D.
Aorta
- E.
Air pressure in the lungs
Correct Answer
C. AV NodeExplanation
The AV Node is responsible for causing contractions of the ventricles of the heart. It receives electrical signals from the SA Node and delays them before transmitting them to the ventricles. This delay allows the atria to fully contract and fill the ventricles with blood before the ventricles contract. The AV Node acts as a gatekeeper, ensuring that the electrical signals are properly timed and coordinated for efficient pumping of blood throughout the body.Rate this question:
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- 11.
What is a characteristic of DNA?
- A.
DNA can be replicated.
- B.
DNA contains phosphate (P).
- C.
DNA contains ribose as its sugar.
- D.
A and B are correct, C is incorrect.
- E.
B and C are correct, A is incorrect.
Correct Answer
D. A and B are correct, C is incorrect.Explanation
DNA can be replicated, meaning that it can make copies of itself. This is a fundamental characteristic of DNA and is essential for cell division and the transmission of genetic information from one generation to the next. Additionally, DNA contains phosphate (P) in its backbone, which helps to stabilize its structure. However, DNA does not contain ribose as its sugar. Instead, it contains deoxyribose, which is a slightly different molecule. Therefore, the correct answer is that A and B are correct, while C is incorrect.Rate this question:
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- 12.
After an mRNA molecule has been produced:
- A.
A complementary mRNA copy must be made so that the mRNA has two strands.
- B.
It leaves the nucleus.
- C.
It must be made into a circle by joining the ends.
- D.
It digests a ribosome.
- E.
None of the above is correct.
Correct Answer
B. It leaves the nucleus.Explanation
After an mRNA molecule has been produced, it leaves the nucleus. This is because mRNA is synthesized in the nucleus during transcription and then it is transported out of the nucleus into the cytoplasm where it can be used as a template for protein synthesis during translation. The mRNA molecule carries the genetic information from the DNA in the nucleus to the ribosomes in the cytoplasm, where proteins are synthesized. Therefore, the correct answer is that the mRNA molecule leaves the nucleus.Rate this question:
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- 13.
DNA replication occurs during:
- A.
Interphase
- B.
Prophase
- C.
Metaphase
- D.
Anaphase
- E.
Telophase
Correct Answer
A. InterpHaseExplanation
DNA replication occurs during interphase. Interphase is the longest phase of the cell cycle, where the cell prepares for division by growing and replicating its DNA. During interphase, the DNA is duplicated in the nucleus, resulting in two identical copies of each chromosome. This ensures that each new daughter cell will have a complete set of genetic information. After DNA replication is complete, the cell enters the next phase of the cell cycle, which includes mitosis or cell division.Rate this question:
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- 14.
If A is dominant to a, the offspring of the cross AA x aa will:
- A.
Be homozygous.
- B.
Have the same genotype as the AA parent.
- C.
Have the same genotype as the aa parent.
- D.
Display the same phenotype as the AA parent.
- E.
Display the same phenotype as the aa parent.
Correct Answer
D. Display the same pHenotype as the AA parent.Explanation
When A is dominant to a, it means that the presence of A will determine the phenotype. In this case, AA represents a homozygous dominant genotype, and aa represents a homozygous recessive genotype. When these two genotypes are crossed, all of the offspring will inherit one dominant A allele from the AA parent, resulting in the same phenotype as the AA parent. Therefore, the offspring will display the same phenotype as the AA parent.Rate this question:
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- 15.
What is a codon?
- A.
A codon is three amino acids in a row.
- B.
A three amino acid portion of mRNA.
- C.
A three nucleotide base sequence in mRNA which codes for an amino acid.
- D.
The sugar phosphate backbone.
- E.
Three DNA bases which code for a tRNA molecule.
Correct Answer
C. A three nucleotide base sequence in mRNA which codes for an amino acid.Explanation
A codon is a three nucleotide base sequence in mRNA that codes for a specific amino acid. This sequence acts as a genetic code that instructs the ribosomes during protein synthesis to link the appropriate amino acids together in the correct order. Each codon corresponds to a specific amino acid, allowing for the precise translation of the genetic information carried by mRNA into the sequence of amino acids that make up a protein.Rate this question:
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- 16.
Air enters the human lung because of:
- A.
Suction from the lung capillaries.
- B.
Vacuum in the pharynx.
- C.
Blood pressure.
- D.
Squeezing of the trachea.
- E.
Atmospheric air pressure.
Correct Answer
E. AtmospHeric air pressure.Explanation
Air enters the human lung due to atmospheric air pressure. When we breathe in, the diaphragm and intercostal muscles contract, causing the volume of the thoracic cavity to increase. This decrease in pressure inside the lungs creates a pressure gradient between the atmosphere and the lungs. As a result, air flows from an area of higher pressure (atmosphere) to an area of lower pressure (lungs), allowing air to enter the lungs. The other options mentioned in the question, such as suction from lung capillaries, vacuum in the pharynx, blood pressure, and squeezing of the trachea, are not accurate explanations for the entry of air into the lungs.Rate this question:
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- 17.
This causes the membrane potential to rise (depolarize) all along the axon.
- A.
K+
- B.
Na+
- C.
Ca++
- D.
Neurotransmitter chemical
- E.
Na+/K+ pump (Sodium/Potassium pump)
Correct Answer
B. Na+Explanation
The given answer states that the rise or depolarization of the membrane potential along the axon is caused by Na+. This suggests that the influx of sodium ions into the axon is responsible for the change in membrane potential. Sodium ions have a positive charge, and their entry into the axon can lead to a shift in the electrical charge of the membrane, causing depolarization. This depolarization is an important step in the propagation of nerve impulses along the axon.Rate this question:
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- 18.
This changes shape to move actin.
- A.
Actin
- B.
ADP/ATP
- C.
Myosin
- D.
Tropomyosin
- E.
Troponin
Correct Answer
C. MyosinExplanation
Myosin is a protein that plays a crucial role in muscle contraction. It interacts with actin, another protein, to generate force and cause movement. Myosin has a unique structure that allows it to change shape and bind to actin, forming cross-bridges. This interaction, fueled by the hydrolysis of ATP, leads to the sliding of actin filaments, resulting in muscle contraction. Therefore, myosin is responsible for changing shape to move actin and facilitate muscle movement.Rate this question:
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- 19.
Glucose is removed from the nephron and reabsorbed into the blood from the:
- A.
Bowman's capsule.
- B.
Collecting tubule.
- C.
Distal tubule.
- D.
Loop of Henle.
- E.
Proximal tubule.
Correct Answer
E. Proximal tubule.Explanation
Glucose is removed from the nephron and reabsorbed into the blood in the proximal tubule. This is because the proximal tubule is responsible for the majority of reabsorption in the nephron. Glucose is actively transported from the tubular fluid into the cells lining the proximal tubule, and then it is transported out of the cells and into the blood vessels surrounding the tubule. This process ensures that glucose, an important nutrient, is not lost in the urine and is instead returned to the bloodstream for use by the body.Rate this question:
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- 20.
The waste product urea is formed in the:
- A.
Bowman's capsule.
- B.
Collecting tubule.
- C.
Gall bladder.
- D.
Liver.
- E.
Red blood cells.
Correct Answer
D. Liver.Explanation
Urea is a waste product that is formed in the liver. It is produced as a result of the breakdown of proteins and amino acids. The liver plays a crucial role in the metabolism of nitrogenous waste, converting ammonia into less toxic urea. Urea is then transported to the kidneys through the bloodstream, where it is filtered out and excreted in urine. Therefore, the liver is responsible for the formation of urea, making it the correct answer.Rate this question:
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- 21.
A specific immune response means that:
- A.
Antibodies are produced only by T cells rather than B cells.
- B.
The response is towards a specific antigen.
- C.
Activated B cells are produced but memory B cells are not produced.
- D.
It occurs only during specific times of the day.
- E.
Only specific cuts or wounds are protected.
Correct Answer
B. The response is towards a specific antigen.Explanation
A specific immune response refers to the immune system's ability to recognize and respond to a specific antigen. This means that when the body encounters a particular antigen, such as a virus or bacteria, the immune system produces a targeted response to eliminate or neutralize that specific antigen. This response involves the activation of specific immune cells, such as T cells and B cells, which produce antibodies or other immune molecules that specifically bind to the antigen, leading to its elimination. This specificity allows the immune system to effectively combat different types of pathogens and protect the body from infections.Rate this question:
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- 22.
One thing which helps make a vaccination work is:
- A.
A mast cell.
- B.
Platelets.
- C.
Memory B cells.
- D.
A slower response to a specific antigen the second time it invades the body.
- E.
Non-specific defense mechanisms.
Correct Answer
C. Memory B cells.Explanation
Memory B cells are a crucial component in making a vaccination work. When the body is exposed to a specific antigen for the first time, B cells produce antibodies to fight against it. However, some of these B cells transform into memory B cells, which "remember" the antigen. If the body is exposed to the same antigen again, memory B cells quickly recognize it and produce a rapid and robust immune response. This quick response helps eliminate the infection before it can cause significant harm, providing long-term immunity.Rate this question:
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- 23.
Cell membrane proteins called Major Histocompatability Complex (MHC) serve to:
- A.
Stimulate release of antibodies from helper T cells.
- B.
Allow the attachment of a muscle to a bone.
- C.
Prevent the backflow of blood in the arteries.
- D.
Slow the clotting of blood to prevent a scar.
- E.
None of the above is correct.
Correct Answer
E. None of the above is correct.Explanation
The correct answer is "none of the above is correct" because Major Histocompatibility Complex (MHC) proteins do not serve any of the mentioned functions. MHC proteins are responsible for presenting antigens to T cells and play a crucial role in the immune system by helping the immune system recognize self from non-self cells. They are not involved in stimulating antibody release, muscle attachment, preventing backflow of blood, or slowing blood clotting.Rate this question:
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- 24.
Which of the following type of bond is used when a peptide bond is formed?
- A.
Covalent
- B.
Ionic
- C.
Both covalent and ionic bonds.
- D.
Bond formed by removing CO2 (carbon dioxide).
- E.
None of the above is used when a peptide bond is formed.
Correct Answer
A. CovalentExplanation
A peptide bond is formed through a covalent bond. Covalent bonds involve the sharing of electrons between atoms, which is exactly what happens when a peptide bond is formed between two amino acids. This bond forms between the carboxyl group of one amino acid and the amino group of another amino acid, resulting in the formation of a peptide chain. Ionic bonds involve the transfer of electrons, which is not the case in a peptide bond formation. Therefore, the correct answer is covalent.Rate this question:
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- 25.
A common characteristic of the formation of polymers is that:
- A.
All types of polymers are made only by plants.
- B.
All types of polymers use peptide bonds.
- C.
All types of polymers are produced using one or more dehydration(=condensation) reactions.
- D.
All types of polymers form CO2 (carbon dioxide) as they form.
- E.
All types of polymers use the same monomers, only arranged in different ways.
Correct Answer
C. All types of polymers are produced using one or more dehydration(=condensation) reactions.Explanation
All types of polymers are produced using one or more dehydration (condensation) reactions. Dehydration reactions occur when monomers join together to form polymers, with the removal of a water molecule. This process allows the monomers to bond together and form longer chains, resulting in the formation of polymers. This characteristic is common to all types of polymers, regardless of their specific composition or arrangement of monomers.Rate this question:
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- 26.
Which of the following statements is NOT true?
- A.
Covalent bonds are strong bonds.
- B.
Covalent bonds form during polymer formation
- C.
The mitochondrion has as its function to produce lipids (= fats).
- D.
A mitochondrion has two separate membranes.
- E.
All membranes are made of a phospholipid bi-layer.
Correct Answer
C. The mitochondrion has as its function to produce lipids (= fats).Explanation
The mitochondrion is an organelle responsible for energy production in the cell through a process called cellular respiration. It is not involved in the production of lipids. Lipid synthesis primarily occurs in the endoplasmic reticulum and the Golgi apparatus.Rate this question:
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- 27.
The tissue type that can be found covering organs and lining openings in the body is:
- A.
Bone
- B.
Epithelium
- C.
Muscle
- D.
Nervous
- E.
Skull
Correct Answer
B. EpitheliumExplanation
Epithelium is the correct answer because it is a tissue type that covers organs and lines openings in the body. Epithelial tissues form the outer layer of the skin and line the respiratory, digestive, and reproductive tracts. They provide protection, absorption, and secretion functions. Bone, muscle, and nervous tissues have different functions and do not cover organs or line openings. The skull is a specific bone structure and does not represent a tissue type.Rate this question:
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- 28.
Which of the following is a lipid (= fat) and is found in cell membranes?
- A.
Amino Acid
- B.
Cholesterol
- C.
Cytoplasm
- D.
Glucose
- E.
Lysosome
Correct Answer
B. CholesterolExplanation
Cholesterol is a lipid that is found in cell membranes. It plays a crucial role in maintaining the fluidity and stability of the membrane. Cholesterol is an essential component of cell membranes and helps regulate the permeability of the membrane, allowing certain molecules to enter or exit the cell. It also acts as a precursor for the synthesis of other important molecules such as hormones and bile acids.Rate this question:
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- 29.
The smallest unit of matter which cannot be broken down chemically is:
- A.
Atom
- B.
Cell
- C.
Molecule
- D.
Organ
- E.
Tissue
Correct Answer
A. AtomExplanation
An atom is the smallest unit of matter that retains the chemical properties of an element. It consists of a nucleus, containing protons and neutrons, surrounded by electrons. Atoms are indivisible and cannot be broken down into simpler substances by chemical means. Cells, molecules, organs, and tissues are all composed of multiple atoms bonded together, making them larger and more complex than atoms. Therefore, the correct answer is atom.Rate this question:
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- 30.
In the following diagram, water is entering the cell. Which of the following is a true statement concerning that diagram, or is (e) the correct reply?
- A.
Water is moving because of active transport.
- B.
Water is moving from low concentration to high concentration.
- C.
Water is moving through an aquaporin, a water pore.
- D.
This water movement produces ATP.
- E.
More than one of the above statements is correct.
Correct Answer
C. Water is moving through an aquaporin, a water pore.Explanation
The diagram shows water entering the cell, indicating that water is moving. The statement "Water is moving through an aquaporin, a water pore" is the only statement that directly relates to the diagram and explains the mechanism of water movement. The other statements do not provide any information about the specific process shown in the diagram. Therefore, the correct answer is "Water is moving through an aquaporin, a water pore."Rate this question:
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- 31.
If one sees the chromosomes of a cell aligned at the center of the cell in a straight line, this cell will be in:
- A.
The G1 phase
- B.
The G2 phase
- C.
This occurs in both the G1 and G2 phases.
- D.
Metaphase
- E.
Prophase
Correct Answer
D. MetapHaseExplanation
During metaphase, the chromosomes of a cell align at the center of the cell in a straight line. This is a crucial step in cell division, specifically during mitosis or meiosis. In metaphase, the spindle fibers attach to the centromeres of the chromosomes and align them along the metaphase plate. This alignment ensures that each daughter cell will receive the correct number of chromosomes during cell division. Therefore, if one sees the chromosomes aligned at the center of the cell in a straight line, it indicates that the cell is in the metaphase stage.Rate this question:
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- 32.
Which of the following diagrams would accurately depict how water molecules form hydrogen bonds with each other? [The squiggle represents a hydrogen bond].
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
C. 3Explanation
Diagram 3 correctly illustrates how water molecules form hydrogen bonds, with the "squiggle" representing the bond between the slightly positive hydrogen of one molecule and the slightly negative oxygen of another. The other diagrams show incorrect bonding between two hydrogens or two oxygens, or hydrogen bonding to a hydrogen atom, which are not how hydrogen bonds form in water.Rate this question:
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- 33.
If a parent cell (assume 1 pair of chromosomes) is to undergo normal mitosis, then each of the daughter cells will have:
- A.
1 pair of chromosomes
- B.
1 chromosome
- C.
4 DNA molecules
- D.
2 chromatids
- E.
1 DNA molecule
Correct Answer
A. 1 pair of chromosomesExplanation
During normal mitosis, the parent cell divides into two daughter cells. Each daughter cell receives an exact copy of the parent cell's chromosomes. Since the parent cell has 1 pair of chromosomes, each daughter cell will also have 1 pair of chromosomes. A pair of chromosomes consists of two chromatids, which are identical copies of each other. Therefore, each daughter cell will have 2 chromatids. The other options, such as 1 chromosome, 4 DNA molecules, or 1 DNA molecule, do not accurately represent the outcome of normal mitosis.Rate this question:
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- 34.
Which of the following regions which are indicated by letters, is a nitrogenous base of a DNA nucleotide?
- A.
A
- B.
B
- C.
C
- D.
D
Correct Answer
C. CExplanation
Region C is a nitrogenous base of a DNA nucleotide. Nitrogenous bases are the building blocks of DNA and there are four types: adenine (A), thymine (T), cytosine (C), and guanine (G). In the given options, only region C is labeled, and therefore it is the correct answer. Without further information about the specific base, it is not possible to determine which specific base it represents (A, T, C, or G).Rate this question:
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- 35.
A ribosome has 3 sites, An E, a P and an A site. Into which site does tRNA enter in order to attach to mRNA?
- A.
E
- B.
P
- C.
A
- D.
TRNA may enter either the E or the A site, but usually the A.
- E.
Except for the first tRNA, tRNA usually enters the A site.
Correct Answer
E. Except for the first tRNA, tRNA usually enters the A site.Explanation
A ribosome has three sites - the E site, the P site, and the A site. The tRNA enters the A site in order to attach to mRNA. However, it is important to note that while tRNA usually enters the A site, there are exceptions. The first tRNA, for example, may enter either the E or the A site.Rate this question:
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- 36.
Assume 2 pair of chromosomes in the parent cell, which have already undergone DNA replication. This diagram below illustrates the Mendel's Law of Segregation because:
- A.
Both members of a pair are in the form of an X like structure, as shown in the diagram.
- B.
One pair of chromosomes are found in one cell, the other pair in the other cell.
- C.
One chromosome of each pair is found in each cell.
- D.
All four chromatids in one of the above cells are identical, same with the other cell.
- E.
Crossing over has occurred.
Correct Answer
C. One chromosome of each pair is found in each cell.Explanation
The correct answer is "one chromosome of each pair is found in each cell." This answer is supported by the statement in the question that there are 2 pairs of chromosomes in the parent cell, which have already undergone DNA replication. During cell division, each pair of chromosomes separates and one chromosome from each pair goes into each new cell. This process is known as the law of segregation, which is a fundamental principle in Mendelian genetics.Rate this question:
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- 37.
The following diagram is of 2 chromosomes of one pair, even though they are of different colors. A true statement concerning this diagram is that:
- A.
The genes A and B, as pictured, will be never found in the same gamete after meiosis.
- B.
The chromosomes can never undergo crossing over during meiosis.
- C.
The chromosomes, as pictured, have been replicated already for mitosis.
- D.
The genes A B and a b are linked.
- E.
The genes A and b cannot ever be on the same chromosome.
Correct Answer
D. The genes A B and a b are linked.Explanation
The correct answer is that the genes A, B, and a, b are linked. This means that they are located close together on the same chromosome and are likely to be inherited together. This can be inferred from the fact that the two chromosomes in the diagram are of different colors, indicating that they are homologous chromosomes from the same pair. Since the genes A and B are on one chromosome and the genes a and b are on the other chromosome, it suggests that these genes are linked and tend to be inherited together.Rate this question:
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- 38.
In the following molecule of mRNA, the number underneath the start codon(s) is (are):
- A.
1
- B.
2
- C.
3
- D.
Both 2 and 3 are START codons.
- E.
The first to start the chain (2 or 3) depending on the direction will be the START codon.
Correct Answer
E. The first to start the chain (2 or 3) depending on the direction will be the START codon.Explanation
The explanation for the given answer is that the number underneath the start codon(s) in the mRNA molecule indicates the position of the start codon(s) in the sequence. The start codon is the codon that signals the beginning of protein synthesis. In this case, there are two possible start codons, 2 and 3. The actual start codon will depend on the direction of the mRNA chain.Rate this question:
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- 39.
There is a mistake in the following DNA. Which numbered arrow points to this mistake?
- A.
1
- B.
2
- C.
3
- D.
4
- E.
None of the arrows points to a mistake.
Correct Answer
D. 4Explanation
Arrow 4 in the diagram highlights a critical error in the DNA sequence where a Thymine (T) base is incorrectly paired with a Guanine (G) base. This violates the fundamental principle of DNA base pairing, where Adenine (A) always bonds with Thymine (T), and Guanine (G) always bonds with Cytosine (C). This specific type of error, where the wrong bases are matched together, is known as a mismatch. Mismatches can arise naturally during the process of DNA replication when the cell makes a copy of its genetic material. However, cells possess sophisticated repair mechanisms to detect and correct these mismatches to maintain the integrity of the DNA sequence. If these mismatches are not repaired, they can potentially lead to mutations, which are permanent alterations in the DNA code. These mutations can have varying consequences, ranging from harmless changes to significant alterations in cellular function.Rate this question:
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- 40.
Assume A is normal vision, a is colorblind vision. In the cross XAXa x XaY, one can say that:
- A.
All possible boys will be colorblind.
- B.
No possible boys will be colorblind.
- C.
All possible girls will be colorblind.
- D.
No possible girls will be colorblind.
- E.
None of the above are true.
Correct Answer
E. None of the above are true.Explanation
The given cross XAXa x XaY involves the inheritance of two traits: normal vision (A) and colorblind vision (a). The genotype of the first parent is XAXa, meaning they have one normal vision allele (A) and one colorblind allele (a). The genotype of the second parent is XaY, meaning they have one colorblind allele (a) and one Y chromosome.
When these parents are crossed, the possible genotypes of their offspring are XAXa (normal vision, carrier), XAY (normal vision, not a carrier), XaXa (colorblind), and XaY (colorblind).
Therefore, it is not true that all possible boys will be colorblind, no possible boys will be colorblind, all possible girls will be colorblind, or no possible girls will be colorblind. The correct answer is that none of the above statements are true.Rate this question:
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- 41.
The epiglottis functions to prevent food from entering the trachea. It is necessary to do this because:
- A.
The esophagus is behind the trachea and food must pass over the trachea to reach the esophagus.
- B.
Otherwise blood enters the trachea.
- C.
One cannot get air into the trachea unless it comes through the mouth. The epiglottis allows this to happen.
- D.
It prevents breathing in (inhalation) while chewing.
- E.
Oxygen cannot enter the trachea otherwise.
Correct Answer
A. The esopHagus is behind the trachea and food must pass over the trachea to reach the esopHagus.Explanation
The epiglottis functions to prevent food from entering the trachea because the esophagus is located behind the trachea. In order for food to reach the esophagus, it needs to pass over the trachea. If the epiglottis did not close off the trachea, food could potentially enter the airway and cause choking or other respiratory issues. Therefore, the role of the epiglottis is crucial in ensuring that food and liquids are directed towards the esophagus and not the trachea.Rate this question:
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- 42.
When an immune system cell ingests an antigen, it may become an antigen-presenting cell. This means that:
- A.
The cell will completely destroy the antigen and then stimulate other cells, kind of like giving them a present.
- B.
A fragment of the antigen is moved into the MHC proteins of the membrane.
- C.
A fragment of the antigen is given to each of two other cell types.
- D.
It must be a macrophage.
- E.
It must be a B cell.
Correct Answer
B. A fragment of the antigen is moved into the MHC proteins of the membrane.Explanation
When an immune system cell ingests an antigen, it may become an antigen-presenting cell. This means that a fragment of the antigen is moved into the MHC proteins of the membrane. This process allows the immune system to recognize the antigen and present it to other immune cells, such as T cells. By presenting the antigen fragment on the MHC proteins, the antigen-presenting cell can activate other immune cells and initiate an immune response against the antigen. This mechanism is crucial for the coordination and regulation of the immune system's response to foreign substances.Rate this question:
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- 43.
Where would one find MHC proteins?
- A.
On a bacterium which contains one or more antigens.
- B.
Floating free in the plasma of the blood.
- C.
In mast cells.
- D.
Only associated with the immune system cells
- E.
On all cells of the body, they denote "self".
Correct Answer
E. On all cells of the body, they denote "self".Explanation
MHC proteins, also known as major histocompatibility complex proteins, can be found on all cells of the body. These proteins play a crucial role in the immune system by presenting antigens to immune cells, helping to identify and eliminate foreign substances. The presence of MHC proteins on all cells helps to distinguish "self" from "non-self" and is essential for proper immune function.Rate this question:
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- 44.
Which of the following releases amylase?
- A.
Esophagus
- B.
Large Intestine
- C.
Pancreas
- D.
Small Intestine
- E.
Stomach
Correct Answer
C. PancreasExplanation
The pancreas releases amylase. Amylase is an enzyme that helps in the breakdown of carbohydrates. It is produced by the pancreas and secreted into the small intestine. Once in the small intestine, amylase breaks down complex carbohydrates into simpler sugars, which can then be absorbed by the body. The other options listed, such as the esophagus, large intestine, stomach, and small intestine, do not release amylase.Rate this question:
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- 45.
The pharynx is:
- A.
The same as the epiglottis.
- B.
The same as a nostril.
- C.
The storage site for feces (= poop).
- D.
The area shared by both digestive and respiratory systems at the back of the mouth.
- E.
A muscle which controls release of material from the gall bladder.
Correct Answer
D. The area shared by both digestive and respiratory systems at the back of the mouth.Explanation
The pharynx is the area shared by both the digestive and respiratory systems at the back of the mouth. It serves as a passageway for both air and food. The epiglottis, on the other hand, is a flap of cartilage that prevents food from entering the trachea during swallowing. The pharynx is not the same as a nostril, the storage site for feces, or a muscle that controls the release of material from the gall bladder.Rate this question:
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- 46.
The material which acts upon pepsinogen to change it to pepsin is:
- A.
Amylase
- B.
Urea
- C.
HCl (hydrochloric acid)
- D.
Bicarbonate from the parietal cells.
- E.
Proteins in the stomach
Correct Answer
C. HCl (hydrochloric acid)Explanation
HCl (hydrochloric acid) is the correct answer because it is the main component of gastric acid in the stomach. HCl activates pepsinogen, an inactive enzyme, and converts it into pepsin, an active enzyme that breaks down proteins. This process is essential for proper digestion of proteins in the stomach. Amylase is an enzyme that breaks down carbohydrates, urea is a waste product excreted by the kidneys, bicarbonate from the parietal cells helps neutralize stomach acid, and proteins in the stomach are broken down by pepsin.Rate this question:
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- 47.
A tendon is indicated by arrow number _____?
- A.
1
- B.
2
- C.
3
- D.
4
- E.
5
Correct Answer
C. 3Explanation
Tendons are tough, fibrous cords of connective tissue that attach muscles to bones. In the image provided, arrow 3 is clearly pointing to the structure connecting the muscle to the bone in the lower leg. Tendons are strong, flexible connective tissues that attach muscles to bones. They play a crucial role in facilitating movement by transmitting the force generated by muscles to the skeletal system, allowing joints to move. Tendons are composed primarily of collagen fibers, which provide tensile strength, enabling them to withstand the stress and strain of muscle contractions.Rate this question:
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- 48.
What can one say about the membrane protein in the following illustration:
- A.
Only K+ is moved by this protein.
- B.
Only Na+ is moved by this protein.
- C.
It usually releases neurotransmitters at the end of the axon.
- D.
It requires ATP to function properly.
- E.
Both Na+ and K+ are moved by this protein, Na+ goes in, K+ goes out.
Correct Answer
D. It requires ATP to function properly.Explanation
The illustration depicts the sodium-potassium pump, a vital active transport protein embedded within the cell membrane. This pump plays a critical role in maintaining the proper balance of sodium (Na+) and potassium (K+) ions inside and outside the cell. Unlike passive transport, which moves molecules along their concentration gradients, this pump works against the concentration gradients. This means it moves Na+ out of the cell and K+ into the cell, even though Na+ is already more concentrated outside the cell and K+ is more concentrated inside. To achieve this, the pump requires energy, which is obtained by breaking down ATP (adenosine triphosphate) into ADP (adenosine diphosphate). This energy fuels the protein's shape changes that allow it to bind, transport, and release the ions. The sodium-potassium pump is essential for a variety of cellular processes, including maintaining cell volume, generating electrical impulses in nerve cells, and facilitating muscle contractions.Rate this question:
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- 49.
__________ hormones have receptors which bind the hormone and then the hormone/receptor complex attaches to DNA.
- A.
All
- B.
No
- C.
Very Large
- D.
Peptide
- E.
Steroid
Correct Answer
E. SteroidExplanation
Steroid hormones have receptors that bind the hormone and form a hormone/receptor complex. This complex then attaches to DNA, allowing the steroid hormone to regulate gene expression. Unlike peptide hormones, which typically bind to cell surface receptors and activate secondary messengers, steroid hormones are able to directly affect gene transcription and protein synthesis. Therefore, the correct answer is "Steroid."Rate this question:
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- 50.
In the hormonal stimulation of cAMP formation, the molecule which is activates adenylyl cyclase to form cAMP is:
- A.
A steroid
- B.
A G protein
- C.
ATP
- D.
A receptor
- E.
A cAMP molecule
Correct Answer
B. A G proteinExplanation
In the hormonal stimulation of cAMP formation, a G protein activates adenylyl cyclase to form cAMP. G proteins are a family of proteins that act as molecular switches inside cells, transmitting signals from various receptors to different cellular pathways. In this case, when a hormone binds to its receptor on the cell surface, it activates a G protein, which then activates adenylyl cyclase. Adenylyl cyclase converts ATP into cAMP, a secondary messenger that further transmits the hormonal signal within the cell. Therefore, a G protein is the molecule that activates adenylyl cyclase to form cAMP in this process.Rate this question:
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![Which of the following diagrams would accurately depict how water molecules form hydrogen bonds with each other? [The squiggle represents a hydrogen bond].
- ProProfs](https://media.proprofs.com/images/QM/user_images/2503852/4.webp "Which of the following diagrams would accurately depict how water molecules form hydrogen bonds with each other? [The squiggle represents a hydrogen bond].")
.webp "Which of the following regions which are indicated by letters, is a nitrogenous base of a DNA nucleotide?")
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