Which of the following statements is true regarding vaccines?
A. Vaccines can cause the disease they are designed to protect against
B. Vaccines work by providing passive immunity to the individual
C. Vaccines work by exposing the individual to a weakened or inactivated form of the pathogen
D. Vaccines only provide protection against bacterial infections
Vaccines are a type of preventative medicine that work by exposing the individual to a weakened or inactivated form of a pathogen (such as a virus or bacteria) or to a piece of the pathogen (such as a protein or sugar) that triggers an immune response in the body. This exposure allows the body to develop immunity to the pathogen without getting sick from the full-blown disease. Once the immune system has been primed, it can recognize and quickly respond to the pathogen if it is encountered again in the future, providing protection against the disease.
It is a common misconception that vaccines can cause the disease they are designed to protect against. This is not true. While some vaccines may cause mild symptoms such as a low-grade fever or soreness at the injection site, they do not cause the full-blown disease.
Vaccines provide active immunity, meaning that the body produces its own antibodies against the pathogen, rather than receiving pre-made antibodies as in passive immunity. Additionally, vaccines can be effective against both bacterial and viral infections, depending on the specific vaccine.
Therefore, the Correct Answer is C.
More Questions on TEAS 7 Science
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Q #1: What is the difference between isotonic and isometric muscle contractions?
A. Isotonic contractions produce no movement while isometric contractions produce movement.
B. Isotonic contractions produce movement while isometric contractions produce no movement.
C. Isotonic contractions generate tension in the muscle while isometric contractions involve shortening of the muscle fibers.
D. Isotonic contractions involve contraction of individual muscle fibers while isometric contractions involve the entire muscle.
Answer Explanation
Isotonic and isometric contractions are two types of muscle contractions that differ in the amount of force produced and the movement of the muscle. In isotonic contractions, the muscle changes length and produces movement, such as lifting a weight. The force generated by the muscle remains constant throughout the movement. Isotonic contractions can be further classified as concentric contractions, in which the muscle shortens as it contracts, and eccentric contractions, in which the muscle lengthens as it contracts.
In contrast, isometric contractions occur when the muscle generates force without changing its length or producing movement. For example, holding a weight in a fixed position without moving it requires an isometric contraction. In an isometric contraction, the force generated by the muscle increases up to a maximum and then remains constant. Isometric contractions can be used to build strength and endurance in the muscle, but they do not produce movement.
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Q #2: What is the name of the joint that allows for rotation of the arm at the shoulder?
A. Elbow joint
B. Hip joint
C. Knee joint
D. Shoulder joint
Answer Explanation
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Q #3: Which of the following statements is true regarding vaccines?
A. Vaccines can cause the disease they are designed to protect against
B. Vaccines work by providing passive immunity to the individual
C. Vaccines work by exposing the individual to a weakened or inactivated form of the pathogen
D. Vaccines only provide protection against bacterial infections
Answer Explanation
Vaccines are a type of preventative medicine that work by exposing the individual to a weakened or inactivated form of a pathogen (such as a virus or bacteria) or to a piece of the pathogen (such as a protein or sugar) that triggers an immune response in the body. This exposure allows the body to develop immunity to the pathogen without getting sick from the full-blown disease. Once the immune system has been primed, it can recognize and quickly respond to the pathogen if it is encountered again in the future, providing protection against the disease.
It is a common misconception that vaccines can cause the disease they are designed to protect against. This is not true. While some vaccines may cause mild symptoms such as a low-grade fever or soreness at the injection site, they do not cause the full-blown disease.
Vaccines provide active immunity, meaning that the body produces its own antibodies against the pathogen, rather than receiving pre-made antibodies as in passive immunity. Additionally, vaccines can be effective against both bacterial and viral infections, depending on the specific vaccine.
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Q #4: What is the role of calcium in muscle contraction?
A. Calcium binds to tropomyosin to expose the myosin-binding sites on actin.
B. Calcium is released from the sarcoplasmic reticulum to initiate the sliding of actin and myosin filaments.
C. Calcium activates the motor neurons to stimulate muscle contraction.
D. Calcium is required for the relaxation of muscles after contraction.
Answer Explanation
Muscle contraction is a complex process that involves the interaction between actin and myosin filaments in the muscle fibers. The sliding of these filaments is initiated by the release of calcium ions from the sarcoplasmic reticulum, a specialized organelle in muscle cells. The calcium ions bind to the protein troponin, which causes a conformational change in the troponin-tropomyosin complex, exposing the myosin-binding sites on actin. This allows the myosin heads to bind to actin, forming cross-bridges that pull the actin filaments towards the center of the sarcomere, resulting in muscle contraction.
Option a) is incorrect because calcium does not bind to tropomyosin directly, but rather binds to the protein troponin, causing a conformational change in the troponin-tropomyosin complex. Option c) is incorrect because calcium does not activate motor neurons, but rather is released from the sarcoplasmic reticulum in response to an action potential that travels down the motor neuron to the neuromuscular junction. Option d) is incorrect because calcium is required for muscle contraction, not relaxation. The relaxation of muscles after contraction is due to the active transport of calcium ions back into the sarcoplasmic reticulum, which allows the troponin-tropomyosin complex to return to its resting conformation, blocking the myosin-binding sites on actin and ending the cross-bridge cycle.
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Q #5: Which of the following is a chemical property of a substance?
A. Density
B. Melting point
C. Boiling point
D. Reactivity with acid
Answer Explanation
Chemical properties are characteristics of a substance that describe its ability to undergo a chemical change or reaction with another substance.
Reactivity with acid is a chemical property because it describes how a substance will react with an acid to produce a new substance. Density, melting point, and boiling point are physical properties that describe how a substance behaves under certain conditions but do not involve a chemical change or reaction.
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Q #6: What is the function of ribosomes in a cell?
A. To produce energy for the cell
B. To store genetic information
C. To transport molecules within the cell
D. To synthesize proteins in the cell
Answer Explanation
Ribosomes are small, spherical structures found in all living cells, including bacteria, archaea, and eukaryotes. Their primary function is to synthesize proteins using the genetic information stored in the cell's DNA. Ribosomes are composed of two subunits, one large and one small, that come together during protein synthesis.
Ribosomes read the genetic information stored in mRNA (messenger RNA) and use this information to assemble amino acids in the correct order to form a protein. The ribosome moves along the mRNA, adding one amino acid at a time to the growing protein chain until it reaches the end of the mRNA and the protein is complete.
Proteins are essential for a wide variety of cellular functions, including catalyzing chemical reactions, providing structural support, and transporting molecules across cell membranes. Therefore, ribosomes play a critical role in the overall function and survival of a cell.
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Q #7: What is the chemical formula for water?
A. H2O
B. CO2
C. NaCl
D. C6H12O6
Answer Explanation
The chemical formula for water is H2O. It consists of two hydrogen atoms and one oxygen atom.
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Q #8: Which part of the respiratory system is responsible for regulating breathing rate and depth?
A. Bronchi
B. Alveoli
C. Diaphragm
D. Trachea
Answer Explanation
Diaphragm is responsible for regulating breathing rate and depth. It is a dome-shaped muscle located at the
bottom of the chest cavity that contracts and relaxes to help move air in and out of the lungs.
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Q #9: Which of the following describes the function of ligaments?
A. Ligaments attach skeletal muscles to bone
B. Ligaments attach two bones
C. Ligaments attach bones to tendons
D. Ligaments attach skeletal muscles to tendons
Answer Explanation
Ligaments are tough bands of fibrous tissue that connect two bones together in a joint. They provide stability and support to the joint, preventing excessive movement and helping to maintain proper alignment of the bones.
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Q #10: What is the molecular geometry of a molecule of sulphur dioxide (SO2)?
A. Linear
B. Trigonal planar
C. Bent
D. Tetrahedral
Answer Explanation
The molecular geometry of a molecule of sulphur dioxide (SO2) is bent or V-shaped. This is because of the presence of two lone pairs on the sulfur atom, which cause repulsion and distort the bond angles in the molecule.
SO2 has a central sulfur atom bonded to two oxygen atoms by double bonds. The two double bonds and the two lone pairs of electrons on sulfur result in a trigonal planar arrangement of electron pairs around the sulfur atom. However, the repulsion between the lone pairs causes the two oxygen atoms to be pulled closer together, resulting in a bent or V-shaped molecular geometry.
The bent molecular geometry of SO2 affects its properties, such as its polarity and reactivity. SO2 is a polar molecule due to the asymmetric distribution of electrons, which results in a partial positive charge on the sulfur atom and partial negative charges on the oxygen atoms. This polarity makes SO2 a good solvent and reactant in chemical reactions, as well as a contributor to air pollution and acid rain.
