ATI TEAS 7
Chemistry
1. An element with atomic number 26 and mass number 56 is most likely to be:
- A. Iron (Fe)
- B. Cobalt (Co)
- C. Nickel (Ni)
- D. Manganese (Mn)
Correct answer: A
Rationale: Iron (Fe) - Fe-56 has 26 protons and aligns with the given atomic number and mass number.
2. Melanin, the pigment responsible for skin color, is produced by
- A. Keratinocytes (These cells produce keratin)
- B. Melanocytes
- C. Sebocytes (These cells produce sebum)
- D. Langerhans cells (These cells are part of the immune system)
Correct answer: B
Rationale: The correct answer is B: Melanocytes. Melanin, the pigment responsible for skin color, is produced by melanocytes, which are specialized cells located in the skin's epidermis. Melanocytes transfer melanin to keratinocytes, the predominant cell type in the epidermis, where it provides protection against UV radiation. Sebocytes produce sebum, an oily substance that helps moisturize the skin and hair. Langerhans cells are a type of immune cell that play a role in the skin's immune response. Therefore, the correct answer is B as melanocytes are specifically responsible for producing melanin.
3. What is the difference between polygenic inheritance and pleiotropy?
- A. Polygenic inheritance involves multiple genes influencing one trait, while pleiotropy involves one gene affecting multiple traits.
- B. Polygenic inheritance is found in simple Mendelian traits, while pleiotropy is found in complex traits.
- C. Polygenic inheritance is always quantitative, while pleiotropy can be qualitative or quantitative.
- D. Both involve multiple genes and multiple traits, but the specific mechanisms differ
Correct answer: A
Rationale: Rationale: - Polygenic inheritance refers to the situation where a trait is influenced by multiple genes, each contributing a small effect to the phenotype. These traits often show continuous variation and are not easily categorized into discrete categories. - Pleiotropy, on the other hand, occurs when a single gene influences multiple, seemingly unrelated traits. This means that a mutation in one gene can lead to multiple phenotypic effects across different traits or characteristics. - Therefore, the key difference between polygenic inheritance and pleiotropy lies in the number of genes involved in influencing a trait (multiple genes in polygenic inheritance vs. one gene in pleiotropy) and the direction of influence (one trait affected by multiple genes in polygenic inheritance vs. multiple traits affected by one gene in pleiotropy).
4. 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. The other choices do not accurately describe the effect of temperature on solubility.
5. Which type of brain wave activity is often seen during REM sleep, associated with dreaming?
- A. Delta waves
- B. Alpha waves
- C. Beta waves
- D. Theta waves
Correct answer: D
Rationale: During REM (rapid eye movement) sleep, the brain is highly active, and theta waves are the dominant brain wave pattern. Theta waves are associated with deep relaxation, creativity, and dreaming. Delta waves are typically seen in deep sleep stages, not during REM sleep. Alpha waves are present when we are awake but relaxed, while beta waves are associated with active thinking and concentration. Therefore, theta waves are the correct answer for brain wave activity during REM sleep.
6. What is the purpose of the periosteum, the tough outer layer of bone?
- A. Produces red blood cells
- B. Provides protection and nourishment to bone
- C. Forms the joint surface
- D. Stores minerals
Correct answer: B
Rationale: The correct answer is B: 'Provides protection and nourishment to bone.' The periosteum is a tough outer layer of bone that serves multiple functions. It provides protection by acting as a barrier against infections and injuries. Additionally, the periosteum contains blood vessels that supply nutrients to the bone cells, aiding in bone growth, repair, and maintenance. While red blood cells are produced in the bone marrow, not in the periosteum, the periosteum's primary role is to support the overall health and integrity of the bone structure.
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