which of the following is not true about dna

ATI TEAS 7

Practice Science TEAS Test

1. Which of the following statements is NOT true about DNA?

A. DNA contains the nucleotides A, T, C, G and is read 5' to 3'.
B. DNA contains genetic information and is tightly coiled with proteins to form chromosomes.
C. DNA contains the nucleotides A, T, C, G and is read 3' to 5'.
D. DNA is a double-stranded molecule connected by hydrogen bonds.

Correct answer: C

Rationale: The correct answer is C because DNA is typically read from the 5' end to the 3' end, not from 3' to 5'. Choices A, B, and D are all true statements about DNA. DNA contains the nucleotides A, T, C, G and is read in a 5' to 3' direction. DNA also contains genetic information and is tightly coiled with proteins to form chromosomes. Additionally, DNA is a double-stranded molecule connected by hydrogen bonds.

2. What is the body's primary defense against pathogens?

A. Phagocytes
B. Antibodies
C. Memory B cells
D. T lymphocytes

Correct answer: A

Rationale: The correct answer is A: Phagocytes. Phagocytes are the body's first line of defense against pathogens. They are innate immune cells that engulf and digest foreign particles like bacteria and viruses, preventing infections. Phagocytes act as the initial barrier to invading pathogens and are part of the innate immune response. Choice B, Antibodies, are produced by B cells in the adaptive immune response. Choice C, Memory B cells, are also part of the adaptive immune response and provide a faster and stronger response upon re-exposure to pathogens. Choice D, T lymphocytes, are part of the adaptive immune response, particularly involved in cell-mediated immunity.

3. Which vitamin deficiency can lead to a condition called pernicious anemia, affecting vitamin B12 absorption in the digestive system?

A. Vitamin A
B. Vitamin B12 (cobalamin)
C. Vitamin D
D. Vitamin E

Correct answer: B

Rationale: Pernicious anemia is caused by a deficiency in vitamin B12 (cobalamin). Vitamin B12 is essential for the production of red blood cells and for the proper functioning of the nervous system. Pernicious anemia occurs when there is a lack of intrinsic factor, a protein produced in the stomach that is necessary for the absorption of vitamin B12 in the digestive system. Vitamin A, Vitamin D, and Vitamin E deficiencies do not lead to pernicious anemia. Vitamin A deficiency can cause night blindness and skin issues, Vitamin D deficiency can lead to rickets or osteomalacia, and Vitamin E deficiency can result in neurological problems and muscle weakness.

4. How does the amplitude of a wave relate to its intensity or loudness?

A. They are inversely proportional.
B. They are directly proportional.
C. They have no relationship.
D. Amplitude affects frequency, not intensity.

Correct answer: B

Rationale: The amplitude of a wave is directly related to its intensity or loudness. In general, the larger the amplitude of a wave, the greater its intensity or loudness. This relationship is due to the fact that the amplitude of a wave represents the maximum displacement of particles in the medium from their rest position. The greater the displacement, the more energy the wave carries, leading to higher intensity or louder sound. Choice A is incorrect because the relationship between amplitude and intensity is direct, not inverse. Choice C is incorrect as there is a clear relationship between amplitude and intensity. Choice D is incorrect as amplitude primarily affects intensity or loudness, not frequency.

5. In ecology, what defines a closed system?

A. Exchanges energy but not matter
B. Exchanges both energy and matter
C. Exchanges neither energy nor matter
D. Recycles nutrients efficiently

Correct answer: A

Rationale: In ecology, a closed system is one that does not exchange matter with its surroundings but can exchange energy. This means that while energy can enter or leave the system, the amount of matter within the system remains constant. Option A correctly defines a closed system in ecology. Choices B and C are incorrect as a closed system does not exchange matter or energy. Option D is unrelated to the concept of a closed system in ecology.