what is a mutation

ATI TEAS 7

TEAS 7 science practice questions

1. What is a mutation?

A. A change in the DNA sequence
B. A type of protein
C. A normal part of the DNA replication process
D. A harmless variation in DNA

Correct answer: A

Rationale: A mutation is defined as a change in the DNA sequence, which can occur due to various factors such as errors during DNA replication, exposure to mutagens (e.g., chemicals, radiation), or spontaneous changes. These alterations can lead to modifications in the genetic information carried by an organism, resulting in effects that can range from harmless variations to causing genetic disorders or diseases. Mutations play a crucial role in genetic diversity and evolution. Choices B, C, and D are incorrect as they do not accurately define what a mutation is. Option B is incorrect because mutations are not a type of protein but rather changes in DNA. Option C is incorrect because while mutations can occur during DNA replication, they are not considered a 'normal' part of the process as they can lead to genetic variations. Option D is incorrect because mutations can have a wide range of effects and are not always harmless variations.

2. Which of the following organs is responsible for the mechanical breakdown of food into smaller pieces?

A. Esophagus
B. Stomach
C. Small intestine
D. Mouth

Correct answer: D

Rationale: The correct answer is D: Mouth. The mouth is responsible for the mechanical breakdown of food through chewing and mixing with saliva. This process is essential for breaking down food into smaller, more digestible pieces before swallowing. The esophagus (choice A) is a muscular tube that transports food from the mouth to the stomach and does not participate in the mechanical breakdown of food. The stomach (choice B) primarily functions to further break down food using acids and enzymes, rather than mechanical means. The small intestine (choice C) is responsible for absorbing nutrients from the digested food, not for the mechanical breakdown of food.

3. Which vitamin is crucial for calcium absorption and synthesized in the skin upon sun exposure?

A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin E

Correct answer: C

Rationale: The correct answer is Vitamin D. Vitamin D is essential for calcium absorption as it helps regulate calcium and phosphorus levels in the body. When the skin is exposed to sunlight, UVB rays convert a compound in the skin to vitamin D. This vitamin is vital for maintaining bone health and ensuring the overall calcium balance in the body. Choices A, B, and D are incorrect. Vitamin A is important for vision and immune function, Vitamin C is essential for collagen synthesis and immune function, and Vitamin E is an antioxidant that helps protect cells from damage by free radicals. However, none of these vitamins are primarily responsible for calcium absorption and synthesized in the skin upon sun exposure.

4. Which hormone, produced by the adrenal glands, plays a crucial role in the body's response to stress, including the regulation of salt and water balance?

A. Aldosterone
B. Epinephrine
C. Cortisol
D. Insulin

Correct answer: A

Rationale: Aldosterone is the correct answer. It is a hormone produced by the adrenal glands that plays a crucial role in the body's response to stress by regulating salt and water balance. Aldosterone acts on the kidneys to increase the reabsorption of sodium and water, helping to maintain blood pressure and electrolyte balance during stressful situations. Epinephrine, also known as adrenaline, and cortisol are other hormones produced by the adrenal glands, but they have different functions in the stress response. Epinephrine primarily acts to increase heart rate and blood flow in response to stress, while cortisol helps regulate metabolism, immune response, and inflammation. Insulin, on the other hand, is produced by the pancreas and is involved in regulating blood sugar levels, not salt and water balance.

5. Which vitamin is produced when the skin is exposed to sunlight?

A. Vitamin A
B. Vitamin D
C. Vitamin K
D. Vitamin E

Correct answer: B

Rationale: Vitamin D is the correct answer. When the skin is exposed to sunlight, it triggers a process where a form of cholesterol in the skin is converted into vitamin D. This vitamin plays a crucial role in aiding calcium absorption in the gut, which is essential for maintaining strong and healthy bones. Vitamin A (Choice A) is important for vision and immune function but is not produced by sunlight exposure. Vitamin K (Choice C) is known for its role in blood clotting and bone metabolism, but it is not produced by sunlight. Vitamin E (Choice D) is an antioxidant that protects cells from damage but is not synthesized in the skin through sunlight exposure.