What is a primer in DNA sequencing?
A. A short piece of double-stranded DNA that binds to the template DNA and acts as a "starter" for the polymerase.
B. A short piece of double-stranded DNA that binds to the primer and acts as a "starter" for the template.
C. A short piece of single-stranded DNA that binds to the template DNA and acts as a "starter" for the polymerase.
D. A short piece of single-stranded DNA that binds to the polymerase and acts as a "starter" for the template.
A primer is a short single-stranded DNA fragment used in certain laboratory techniques, such as the polymerase chain reaction (PCR).
In the PCR method, a pair of primers hybridizes with the sample DNA and defines the region that will be amplified.
Choice A) A short piece of double-stranded DNA that binds to the template DNA and acts as a “starter” for the polymerase is incorrect because primers are single-stranded, not double-stranded.
Choice B) A short piece of double-stranded DNA that binds to the primer and acts as a “starter” for the template is incorrect because it does not make sense for a primer to bind to itself.
Choice D) A short piece of single-stranded DNA that binds to the polymerase and acts as a “starter” for the template is incorrect because primers bind to the template DNA, not to the polymerase.
Note: DNA primers are used instead of RNA primers in DNA sequencing and PCR because DNA is more stable, specific, and compatible with the enzymes and processes involved in these techniques.
Therefore, the Correct Answer is C.
More Questions on TEAS 7 Science
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Q #1: Which hormone is responsible for the development of female secondary sexual characteristics such as breast development, menstrual cycle, and widening of hips?
A. Progesterone
B. Testosterone
C. Estrogen
D. FSH
Answer Explanation
The correct answer is choice C. Estrogen.
Estrogen is a steroid hormone responsible for the development of female secondary sexual characteristics such as breast development, menstrual cycle, and widening of hips.
Choice A, Progesterone, is not the correct answer because it is required to maintain pregnancy and delivery.
Choice B, Testosterone, is not the correct answer because it is a hormone produced by the testes which controls the development of male secondary sexual characteristics.
Choice D, FSH (Follicle Stimulating Hormone), is not the correct answer because it stimulates the growth of ovarian follicles in females and regulates spermatogenesis in males.
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Q #2: What is the relationship between viruses and their host cells during replication?
A. Viruses use the host’s replication processes to produce progeny virus particles.
B. Viruses divide inside the host cell to produce progeny virus particles.
C. Viruses have their own replication processes and do not need the host cell.
D. Viruses infect the host cell and destroy it completely.
Answer Explanation
Viruses use the host’s replication processes to produce progeny virus particles.
Viruses are obligate intracellular parasites, meaning that they require a host cell to replicate.
They hijack the host cell’s machinery to produce new virus particles.
Choice B is incorrect because viruses do not divide inside the host cell.
Instead, they use the host cell’s machinery to produce new virus particles.
Choice C is incorrect because viruses do not have their own replication processes and rely on the host cell for replication.
Choice D is incorrect because while some viruses may destroy the host cell during replication, this is not always the case and is not the primary relationship between viruses and their host cells during replication.
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Q #3: Which of the following organelles is responsible for modifying, sorting and packaging proteins and lipids?
A. Golgi apparatus
B. Mitochondria
C. Ribosomes
D. Endoplasmic reticulum
Answer Explanation
The correct answer is choice A. Golgi apparatus.
The Golgi apparatus is a membrane-bound organelle that is responsible for transporting, modifying, and packaging proteins and lipids into vesicles for delivery to targeted destinations.
Choice B is incorrect because mitochondria are responsible for energy production.
Choice C is incorrect because ribosomes are responsible for protein production.
Choice D is incorrect because the endoplasmic reticulum is responsible for lipid production and protein production, but not for modifying, sorting and packaging proteins and lipids.
