Correct Answer: A

Rationale: The cellular membrane is primarily composed of a phospholipid bilayer, which consists of two layers of phospholipid molecules. These molecules have a hydrophilic (water-attracting) head and hydrophobic (water-repelling) tail, creating a barrier that separates the internal cellular environment from the external surroundings. While proteins are embedded within this bilayer and act as transport channels, receptors, and structural support, carbohydrates are found on the outer surface of the membrane for cell recognition and signaling purposes.
Therefore, the correct answer is a bilayer of phospholipid molecules.

Correct Answer: C

Rationale: The correct answer is C: Binary fission. This is the main process through which most bacteria reproduce asexually. During binary fission, a single cell divides into two identical cells, each containing a copy of the genetic material.

Choices A and B, meiosis and mitosis, are processes involved in sexual reproduction and are not used by bacteria for asexual reproduction.
Choice D, interphase, is a stage of the cell cycle where the cell prepares for division and is not a method of reproduction.

Correct Answer: A

Rationale: The correct answer is A, Punnett square. A Punnett square is a tool specifically designed to predict the genotype and phenotype combinations of offspring resulting from a particular cross or breeding experiment. It helps in understanding the probability of different genotypes and phenotypes appearing in the offspring.
Choice B, Chi-square, is a statistical test used to determine if there is a significant difference between the expected frequencies and the observed frequencies in a study.
Choice C, Microscope, is used for viewing tiny structures and organisms, not for predicting genetic outcomes.
Choice D, None of these, is incorrect as Punnett square is a valid tool for predicting genetic outcomes in offspring.

Correct Answer: C

Rationale: The correct answer is C: Uracil. Uracil is found in RNA, not DNA. The four nitrogenous bases in DNA are adenine, thymine, cytosine, and guanine.
Choice A, Adenine, is a nitrogenous base in DNA.
Choice B, Guanine, is another nitrogenous base in DNA.
Choice D, Thymine, is also one of the four nitrogenous bases in DNA.
Therefore, the correct answer is Uracil (
Choice
C).

Correct Answer: D

Rationale: The correct answer is D: In the nucleus. Transcription, the initial step of protein synthesis, takes place in the nucleus where DNA is transcribed into mRNA. This mRNA then leaves the nucleus and enters the cytoplasm where translation occurs on the ribosomes.

Choices A, B, and C are incorrect because transcription specifically occurs in the nucleus, not in the cytoplasm, nuclear envelope, or ribosome unit.