Chapter 17, Problem 8STP

Summary Introduction

Introduction:

The eukaryotic cells have membrane-bound cell organelles and prokaryotic cells do not have membrane-bound cell organelles. The eukaryotic cells have a well-defined nucleus while Prokaryotes have no nucleus and its genetic material is scattered into the cell. Examples of prokaryotes are blue-green algae, bacteria and mycoplasma.

Answer to Problem 8STP

Correct answer:

Option (A), chloroplast.

Explanation of Solution

Explanation correct answer:

Option (A): Chloroplast. The endosymbiont theory was proposed by Evolutionist Lynn Margulis. His theory states that certain organelles of the eukaryotic cells were once prokaryotic microbes. Mitochondria and chloroplasts are the same in eukaryotes as that of prokaryotic cells and divide by binary fission. Mitochondria and chloroplasts have their own DNA which is circular, not linear.

Chloroplasts have their own DNA, generally denoted as cpDNA. The chloroplast DNA contains genes for 28 thylakoid proteins and the large Rubisco subunit for photosynthesis. Additionally, its genes encode eleven subunits of a protein complex which facilitates redox reactions to recycle electrons, which is similar to the enzyme NADH dehydrogenase found in mitochondria. Hence, this option is correct.

Explanation correct answer:

Option (B): The Golgi apparatus packages molecules processed by the endoplasmic reticulum to be transported out of the cell. Hence, this option is incorrect.

Option (C): The Nucleus assists the cell as a command center, send directions to the cell to grow, mature, divide, or die. It also houses DNA (deoxyribonucleic acid), the cell’s genetic material. The nucleus is enclosed by a membrane called the nuclear envelope, which guards the DNA and separates the nucleus from the rest of the cell. Hence, this option is incorrect.

Option (D): Ribosomes are cell organelles that process the cell’s genetic instructions to form proteins. These organelles can float easily in the cytoplasm or be associated with the endoplasmic reticulum. Hence, this option is incorrect.