Nucleolus MCQ

The nucleolus is a unique structure seen in eukaryotic cells’ nuclei. It is basically involved in the assembly of ribosomes, the modification of transfer RNA, and also in the detection of cellular stress. RNA and proteins help in the formation of the nucleolus, which is formed around particular chromosomal areas. It is one of the nucleus’s most important components. The structural components are the RNA and DNA chains, as well as other components. Deoxyribonucleic acid, ribonucleic acid, and proteins are the main components of the nucleolus.

Q1. What is the name of the eukaryotic cell’s control centre?

1. Ribosome

2. Nucleus

3. Cytoplasm

4. Golgi complex

Answer. The correct answer is option ‘2’ nucleus. The nucleus, also known as the control centre of the eukaryotic cell, houses the majority of the cell’s genetic material. A single nucleus (uninucleate) or several nuclei (multinucleate) eukaryotic cell (multinucleate).

Q2. State true or false whether Red blood cells are multinucleated in nature. 

1. True

2. False

Answer. The correct answer is option ‘2’ false. Because mature red blood cells lack a nucleus, they are neither multinucleated or uninucleate.

Q3. Which of the microorganisms below has two nuclei?

1. Slime moulds

2. Paramecium

3. Amoeba

4. Cyanobacteria

Answer. The correct answer here is option ‘3’ paramecium. Paramecium is a unicellular ciliate protozoa that possesses two nuclei, one is macronucleus and other is micronucleus. Genes that are required for everyday function of the cell is stored in macronucleus and sexual reproduction is controlled mainly by the micronucleus.

Q4. Which among the following organelles contain genetic material?

1. Endoplasmic reticulum

2. Nucleolus

3. Nucleus

4. Nucleus and mitochondria

Answer. The correct answer is option ‘4’ nucleus and mitochondria. Each individual’s genetic code is stored in the nucleus, while mitochondrial DNA is stored in a semi autonomous organelle called the mitochondria (passed through the maternal line). The proteins involved in the electron transport chain are coded specifically in mDNA, allowing them to be implanted in the inner mitochondrial membrane without needing to be manufactured elsewhere in the cell.

Q5. Which among the following is the direct role of the nucleolus in the cell?

1. DNA synthesis

2. Protein synthesis

3. rRNA production

4. ATP production

Answer. The correct answer is option ‘3’ rRNA production. The nucleolus, which is found in the nucleus, has a direct role in rRNA production. The ribosome structure is made up of rRNA, which is directly engaged in protein synthesis.

Q6. The structure where ribosomes are produced and where it is transcribed is known as the 

1. Nucleolus . . . miRNA

2. Nucleolus . . . rRNA

3. Nuclear pore . . . mRNA

4. Nuclear pore . . . tRNA

Answer. The correct answer is option ‘2’ nucleolus . . . rRNA. The nucleolus is a unique structure within the nucleus that is important for rRNA gene transcription and ribosomal subunit production. Other parts of the nucleus are used for mRNA, tRNA, and miRNA transcription. Nuclear pores are tightly controlled structures that allow elements to enter and exit the nucleus.

Q7. Which cellular structure is responsible for the formation of ribosomal subunits?

1. Smooth endoplasmic reticulum

2. Rough endoplasmic reticulum

3. Golgi apparatus

4. Nucleolus

Answer. Correct answer is option ‘4’ nucleolus. The nucleolus is a structure within the eukaryotic nucleus. It is in charge of producing ribosomal subunits as well as the rRNA that will be incorporated into ribosomes. Ribosomal subunits are made in the nucleolus and exported to the cytoplasm, where they can be put together to form functional translation complexes.

Q8. A nuclear pore complex can pass through which of the following 

1. Pre-mRNA

2. Ribosomal subunits

3. Transcription factors

4. Mitochondria

1. I, II, and III

2. I, II, III, and IV

3. I, III, and IV

4. I and III

Answer. The correct answer is option ‘1’ i.e. I, II, and III. Mitochondria are the sole option that cannot pass the nuclear envelope from the nucleus. Mitochondria have a diameter of 0.5-1.0 micrometres, while nuclear pore complexes have a diameter of 120 nanometers. Mitochondria, on the other hand, are too big to pass through a nuclear pore complex. Given the right conditions, ribosomes, pre-mRNA, and proteins (such as transcription factors) are all capable of passing through nuclear pore complexes.

Q9. A physician discovers that a patient has a deficiency in the genetic material that codes for ribosomes after doing a genetic analysis. Where does this genetic material reside in the cell?

1. Nuclear envelope

2. Nucleolus

3. Periplasm

4. Histones

Answer. The correct answer is option ‘2’ nucleolus. The nucleolus contains genetic information that codes for ribosomes. Remember that the nucleolus is a specialised structure within the nucleus that is responsible for assembling ribosomes from proteins and ribosomal RNA (rRNA). The rRNA-coding DNA is found on the nucleolus or in close proximity to it.In gram-negative bacteria, the periplasm is the gap between the inner and outer cell membrane; it has no bearing on this subject. The phospholipid bilayer that covers the nucleus is known as the nuclear envelope. It doesn’t have any genetic information in it. Histones are non-genetically encoded proteins that arrange and shape DNA strands.

Q10. The nucleus’s non-membrane bound body that vanishes in late prophase and reappears in telophase

1. Nucleoplasm

2. Chromosome

3. Nucleolus

4. Nuclear pore

Answer. 3.The nucleolus is a non-membrane bound structure created by the nucleolar-organising region of a chromosome and is a component of the nucleus. It vanishes during late prophase and reappears during cell division’s telophase stage.

Q11. Nucleoli were discovered by

1. Robert Hooke

2. Felice Fontana

3. Robert Brown

4. Leeuwenhoek

Answer. The correct answer is option ‘2’ Felice Fontana. 

Q12. What is the name of the signal that allows proteins to enter or exit the nucleus?

1. Notch signal

2. Paracrine signal

3. Nuclear localization signal

4. Chemical signals

Answer. The correct answer is option ‘4′ nuclear localisation signal. Nuclear localization signals, also called nuclear-export signals, aid protein import and export in the nucleus via nuclear pores. Specific amino acid sequences on the proteins serve as these signals.