the term barn is a unit commonly used in nuclear physics to quantify

ATI TEAS 7

TEAS 7 science study guide free

1. In nuclear physics, the term 'barn' is a unit commonly used to quantify:

A. Energy
B. Radioactivity
C. Nuclear cross-section
D. Half-life

Correct answer: C

Rationale: In nuclear physics, the term 'barn' is a unit used to quantify nuclear cross-section. Nuclear cross-section is a measure of the probability of a nuclear reaction occurring when an atomic nucleus interacts with a particle or another nucleus. The barn is a unit of area equal to 10^-28 square meters; it is commonly used to describe the cross-sectional area of atomic nuclei for nuclear reactions. Choice A, 'Energy,' is incorrect because a barn is not a unit for measuring energy; it is a unit of area. Choice B, 'Radioactivity,' is incorrect as radioactivity is typically measured in units like becquerels. Choice D, 'Half-life,' is also incorrect as half-life is a measure of the time it takes for half of a substance to decay, not related to the concept of a barn as a unit of nuclear cross-section.

2. Differentiate between gene therapy and genetic engineering in the context of human intervention.

A. Gene therapy aims to modify existing genes within body cells, while genetic engineering manipulates genes in embryos to be passed on to offspring.
B. Gene therapy focuses on treating genetic diseases, while genetic engineering enhances desirable traits or eliminates undesirable ones.
C. Both involve directly altering the DNA sequence, but gene therapy targets somatic cells and genetic engineering modifies germline cells.
D. There is no fundamental difference; both terms are synonymous.

Correct answer: B

Rationale: A) Incorrect. Gene therapy does aim to modify existing genes within body cells, but genetic engineering does not necessarily manipulate genes in embryos to be passed on to offspring. Genetic engineering can involve modifying genes in any type of cell, not just embryos. B) Correct. Gene therapy is a medical intervention that aims to treat genetic diseases by correcting or replacing faulty genes within an individual's body cells. On the other hand, genetic engineering involves modifying genes to enhance specific traits or eliminate undesirable ones, often in the context of agriculture or biotechnology. C) Incorrect. While both gene therapy and genetic engineering involve altering DNA sequences, the distinction lies in the target cells. Gene therapy targets somatic cells (non-reproductive cells), while genetic engineering typically involves modifying germline cells (reproductive cells that can pass on genetic changes to offspring). D) Incorrect. There is

3. What is the primary function of DNA polymerase?

A. Packaging DNA
B. Replicating DNA
C. Transcribing DNA
D. Translating mRNA

Correct answer: B

Rationale: The correct answer is B: Replicating DNA. DNA polymerase is an enzyme responsible for synthesizing new DNA strands during DNA replication. It adds nucleotides to the growing DNA strand based on the template provided by the existing DNA strand. This process ensures that genetic information is accurately copied and passed on to daughter cells during cell division. Option A, Packaging DNA, refers to the coiling and organization of DNA into chromatin, a process involving histones and other proteins. Option C, Transcribing DNA, involves the synthesis of RNA from a DNA template, a process carried out by RNA polymerase. Option D, Translating mRNA, refers to the process of protein synthesis where the information encoded in mRNA is used to assemble amino acids into a polypeptide chain.

4. Which type of cell has a nucleus but lacks membrane-bound organelles?

A. Plant cell
B. Prokaryotic cell
C. Animal cell
D. Fungal cell

Correct answer: B

Rationale: The correct answer is B: Prokaryotic cell. Prokaryotic cells are characterized by having a nucleus that is not enclosed within a membrane (nuclear envelope) and lacking membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus. Plant, animal, and fungal cells are eukaryotic cells, which have a true nucleus enclosed within a nuclear envelope and contain membrane-bound organelles. Therefore, options A, C, and D are incorrect as they all represent eukaryotic cells that possess membrane-bound organelles.

5. What is the primary function of the mucous membrane lining the muscular tube connecting the mouth to the stomach?

A. Secretion of digestive enzymes
B. Absorption of nutrients
C. Lubrication and protection
D. Storage of bile

Correct answer: C

Rationale: The primary function of the mucous membrane lining the muscular tube connecting the mouth to the stomach is to provide lubrication and protection. This mucous membrane serves to protect the esophageal lining from damage caused by the passage of food and liquids. It also aids in facilitating the smooth passage of food from the mouth to the stomach by lubricating it, ensuring easier movement. Choices A, B, and D are incorrect as the mucous membrane does not secrete digestive enzymes, absorb nutrients, or store bile. Its main role is primarily related to lubricating and protecting the lining of the tube.