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What is the name of the regulatory region in a gene that controls its expression?
- A. Exon
- B. Intron
- C. Promoter
- D. Enhancer
Correct Answer: C
Rationale: A) Exon: Exons are the coding regions of a gene that are transcribed into mRNA and eventually translated into proteins. Exons do not regulate gene expression.
B) Intron: Introns are non-coding regions of a gene that are removed during RNA processing and do not play a direct role in controlling gene expression.
C) Promoter: The promoter is a regulatory region located at the beginning of a gene that initiates the process of transcription by binding transcription factors and RNA polymerase. It plays a crucial role in controlling gene expression.
D) Enhancer: Enhancers are regulatory regions that can be located far from the gene they regulate and can increase the transcription of a gene. While enhancers are important for gene expression, the specific region that controls gene expression is the promoter.
Therefore, the correct answer is C) Promoter, as it is the regulatory region in a gene that controls its expression by initiating transcription.
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Which type of RNA carries the genetic code from DNA to ribosomes?
- A. Ribosomal RNA (rRNA)
- B. Transfer RNA (tRNA)
- C. Messenger RNA (mRNA)
- D. Deoxyribonucleic acid (DNA)
Correct Answer: C
Rationale: - Messenger RNA (mRNA) carries the genetic information from DNA in the cell's nucleus to the ribosomes in the cytoplasm, where protein synthesis occurs.
- Ribosomal RNA (rRNA) is a component of the ribosomes where protein synthesis takes place.
- Transfer RNA (tRNA) is responsible for bringing amino acids to the ribosomes during protein synthesis.
- Deoxyribonucleic acid (DNA) is the genetic material that contains the instructions for building and maintaining an organism. DNA is transcribed into mRNA before being translated into proteins.
What is the difference between a sensory neuron and a motor neuron?
- A. Sensory neurons carry signals from sensory receptors towards the central nervous system, while motor neurons carry signals away from the central nervous system to muscles and glands.
- B. Sensory neurons control voluntary muscles, while motor neurons control involuntary muscles.
- C. Sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system.
- D. Sensory neurons detect light, while motor neurons detect sound.
Correct Answer: A
Rationale: Sensory neurons are responsible for carrying signals from sensory receptors towards the central nervous system (brain and spinal cord), allowing the brain to receive information about the external environment. On the other hand, motor neurons carry signals away from the central nervous system to muscles and glands, enabling the brain to control voluntary and involuntary movements. Choice B is incorrect because sensory neurons do not control muscles, and motor neurons control both voluntary and involuntary muscles. Choice C is incorrect as sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system. Choice D is incorrect because sensory neurons detect various stimuli such as touch, taste, smell, and sound, while motor neurons are not involved in detecting sensory stimuli.
In physics, what does the term 'terminal velocity' refer to?
- A. Maximum velocity reached by an object in free fall
- B. Velocity when the object is at rest
- C. Instantaneous velocity of an object
- D. Velocity only reached by heavy objects
Correct Answer: A
Rationale: Terminal velocity in physics refers to the maximum velocity achieved by an object in free fall when the force of gravity equals the force of air resistance. At terminal velocity, the object stops accelerating and maintains a constant speed. This occurs when the opposing forces are balanced, leading to no further increase in speed. Choice B is incorrect as velocity when the object is at rest is zero, not at terminal velocity. Choice C is incorrect as instantaneous velocity refers to the velocity at a specific moment in time, not the maximum speed reached in free fall. Choice D is incorrect because terminal velocity is not exclusive to heavy objects; all objects in free fall can reach terminal velocity under the right conditions.
What are the three main types of muscle tissue in the human body?
- A. Smooth, cardiac, and voluntary skeletal
- B. Smooth, skeletal, and involuntary cardiac
- C. Voluntary smooth, cardiac, and skeletal
- D. Striated, non-striated, and epithelial
Correct Answer: A
Rationale: The three main types of muscle tissue in the human body are smooth muscle (involuntary), cardiac muscle (involuntary), and voluntary skeletal muscle. Smooth muscle is found in the walls of hollow organs, cardiac muscle is found in the heart, and skeletal muscle is attached to bones and is under voluntary control. Option A correctly identifies these three main types of muscle tissue in the human body. Choice B is incorrect because it lists skeletal muscle as involuntary, which is not accurate. Choice C is incorrect because it lists voluntary smooth muscle, which does not exist as smooth muscle is involuntary. Choice D is incorrect because it uses terms like striated, non-striated, and epithelial, which are not the main types of muscle tissue but rather descriptions related to muscle characteristics and location.
How does an increase in temperature generally affect the solubility of most solid solutes in a liquid solvent?
- A. It increases solubility
- B. It decreases solubility
- C. It has no effect on solubility
- D. It depends on the nature of the solute
Correct Answer: A
Rationale: In general, increasing temperature tends to increase the solubility of most solid solutes in liquid solvents. This occurs because higher temperatures provide more energy for the solvent molecules to break the solute-solvent attractive forces and allow more solute to dissolve. The increase in temperature facilitates the dissolution process by overcoming the intermolecular forces that hold the solute particles together. Choice B is incorrect because higher temperatures typically lead to greater solubility. Choice C is incorrect as temperature changes usually impact solubility. Choice D is incorrect because although the nature of the solute can influence solubility, the general trend is that higher temperatures enhance solubility for most solid solutes in liquid solvents.