Nokea
Which of the following is not true about antibiotics?
- A. They can interfere with the bacteria's ability to survive
- B. They can affect how bacteria multiply
- C. They can cause more bacteria to grow
- D. They only work on bacteria
Correct Answer: C
Rationale: The correct answer is C. Antibiotics do not cause more bacteria to grow. They work by interfering with the bacteria's ability to survive, affecting how they multiply, or killing the bacteria cells. Antibiotics specifically target bacteria, so they do not promote the growth of more bacteria. Choices A, B, and D are true statements about antibiotics as they accurately describe how antibiotics work and their specific action on bacteria.
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Which is true of gametes?
- A. They are diploid cells
- B. They are haploid cells
- C. They are somatic
- D. A & C are true
Correct Answer: B
Rationale: Gametes are sex cells (sperm and eggs) that are involved in sexual reproduction. They are haploid cells, meaning they have half the number of chromosomes (n) compared to diploid cells. This is necessary for the formation of a diploid zygote when two gametes unite during fertilization. Somatic cells are non-reproductive cells in the body, so they are not gametes. Choice A is incorrect because gametes are not diploid but haploid. Choice C is incorrect because gametes are not somatic cells.
DNA bases include all but which of the following?
- A. Adenine
- B. Thymine
- C. Uracil
- D. Cytosine
Correct Answer: C
Rationale: The correct answer is C: Uracil. Uracil is not a DNA base; it is a base found only in RNA. The four bases in DNA are Adenine, Thymine, Cytosine, and Guanine. Choice A, Adenine, is a correct DNA base. Choice B, Thymine, is a correct DNA base. Choice D, Cytosine, is a correct DNA base. Therefore, Uracil is the only incorrect choice among the options provided.
Which of the following arrangement is seen in the plasma membrane?
- A. Lipids with embedded proteins
- B. An outer lipid layer and an inner lipid layer
- C. Proteins embedded in lipid bilayer
- D. Altering protein and lipid layers
Correct Answer: C
Rationale: The correct arrangement seen in the plasma membrane is proteins embedded in the lipid bilayer. The plasma membrane is composed of a lipid bilayer with embedded proteins. These proteins perform various functions such as transport, signaling, and structural support within the cell membrane. This arrangement allows for the selective permeability of the membrane and facilitates communication between the cell and its environment. Choices A, B, and D are incorrect because the primary arrangement in the plasma membrane involves proteins being embedded in the lipid bilayer, not lipids with embedded proteins, an outer and inner lipid layer, or altering protein and lipid layers.
Which two bases are purines?
- A. Adenine (A)
- B. Cytosine (C)
- C. Thymine (T)
- D. Guanine (G)
Correct Answer: A
Rationale: Adenine (A) and guanine (G) are the two bases that are purines. Purines are characterized by a double-ring structure containing two carbon rings, distinguishing them from pyrimidines. Adenine and guanine are purines because they possess this unique double-ring structure. Therefore, choices A and D, adenine and guanine, respectively, are the correct answers. Choices B and C, cytosine and thymine, are pyrimidines and do not exhibit the double-ring structure characteristic of purines.
A cell from heart muscle would more than likely contain an unusually high proportion of which of the following?
- A. lysosomes
- B. mitochondria
- C. mRNA
- D. ribosomes
Correct Answer: B
Rationale: A cell from heart muscle would more than likely contain an unusually high proportion of mitochondria because the heart muscle requires a significant amount of energy to function properly. Mitochondria are the powerhouse of the cell and are responsible for producing energy in the form of ATP through cellular respiration. Therefore, to meet the high energy demands of the heart muscle, it would need a higher concentration of mitochondria compared to other cell types. Choices A, C, and D are incorrect because while lysosomes, mRNA, and ribosomes are essential components of a cell, they do not play as direct a role in meeting the high energy demands of heart muscle as mitochondria do.