which of the following structures helps filter pathogens from the blood

ATI TEAS 7

Practice Science TEAS Test

1. Which of the following structures helps filter pathogens from the blood?

A. Lymph nodes
B. Kidneys
C. Spleen
D. Pancreas

Correct answer: C

Rationale: The spleen is the correct answer. The spleen is a vital organ in the immune system responsible for filtering pathogens from the blood. It contains specialized immune cells that aid in recognizing and eliminating harmful substances. Additionally, the spleen plays a role in recycling old red blood cells. Choices A, B, and D are incorrect. Lymph nodes primarily filter lymph fluid, not blood. Kidneys are involved in filtering waste and regulating fluid balance, not specifically filtering pathogens from the blood. The pancreas functions in hormone regulation and digestion, unrelated to filtering pathogens from the blood.

2. What is the role of RNA interference in silencing genes?

A. Increases protein production
B. Promotes gene mutation
C. Inhibits the expression of specific genes
D. Repairs damaged DNA

Correct answer: C

Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, 'Inhibits the expression of specific genes,' is the correct role of RNA interference in silencing genes. Options A, B, and D are incorrect because RNA interference does not increase protein production, promote gene mutation, or repair damaged DNA; its primary function is to inhibit gene expression by degrading or interfering with mRNA.

3. What is the role of transfer RNA (tRNA) in protein synthesis?

A. Transcribes DNA into mRNA
B. Decodes the genetic code on mRNA
C. Carries specific amino acids to the ribosomes
D. Modifies the structure of proteins

Correct answer: C

Rationale: A) Transcribes DNA into mRNA: This is the function of RNA polymerase, not transfer RNA (tRNA). tRNA is involved in protein synthesis, not transcription. B) Decodes the genetic code on mRNA: This is the function of tRNA during translation. tRNA molecules carry specific amino acids and recognize the codons on mRNA, ensuring the correct amino acid is added to the growing polypeptide chain. C) Carries specific amino acids to the ribosomes: This is the primary role of tRNA in protein synthesis. Each tRNA molecule is specific for a particular amino acid and carries it to the ribosome, where it is added to the growing protein chain. D) Modifies the structure of proteins: This is not a function of tRNA. Protein modification can occur after translation is complete and involves other cellular processes and molecules.

4. Which of the following is an example of a weak acid?

A. Hydrochloric acid (HCl)
B. Sulfuric acid (H2SO4)
C. Acetic acid (CH3COOH)
D. Nitric acid (HNO3)

Correct answer: C

Rationale: The correct answer is Acetic acid (CH3COOH) because it is a weak acid that only partially dissociates in water, resulting in a lower concentration of H+ ions compared to strong acids like hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid (HNO3) which completely dissociate in water. Weak acids do not fully ionize in water, leading to a lower concentration of H+ ions in solution. Hydrochloric acid, sulfuric acid, and nitric acid are strong acids that completely dissociate in water, producing a higher concentration of H+ ions. Therefore, they are not examples of weak acids.

5. Following successful heart transplant surgery, the patient's body will need to take medications to:

A. Suppress the immune system and prevent rejection of the new heart.
B. Reduce overall blood pressure.
C. Dissolve any remaining blood clots.
D. Stimulate the growth of new heart tissue.

Correct answer: A

Rationale: After heart transplant surgery, the patient's body will need to take medications to suppress the immune system and prevent rejection of the new heart. This is essential to ensure that the body does not identify the transplanted heart as a foreign entity and mount an immune response against it, which could lead to transplant rejection and failure. Choices B, C, and D are incorrect because post-heart transplant medications primarily focus on preventing rejection by suppressing the immune system, rather than reducing blood pressure, dissolving blood clots, or stimulating the growth of new heart tissue.