Nucleus: Structure and Function - Cell Biology for Doctor of Medicine

Question 1

Within the nucleus, which structure is dedicated to the synthesis of ribosomes?

Accepted Answer

Nucleolus

Answer

Nuclear envelope

Answer

Chromatin

Question 2

Which of the following is NOT a component of the nuclear envelope?

Accepted Answer

Ribosomes on the cytoplasmic face

Answer

Double lipid bilayer membrane

Answer

Nuclear pore complexes

Answer

Lamin proteins of the nuclear lamina

Question 3

The decondensed form of DNA surrounded by proteins within the nucleus is called:

Accepted Answer

Chromatin

Answer

Chromosome

Answer

Histone

Answer

Nucleosome

Question 4

Which of the following proteins is primarily responsible for packaging DNA into chromatin fibers?

Accepted Answer

Histones

Answer

Nucleolin

Answer

Polymerase

Answer

Helicase

Question 5

The primary function of the nucleolus is to:

Accepted Answer

Synthesize ribosomal RNA

Answer

Produce proteins

Answer

Regulate cell division

Answer

Store genetic material

Question 6

The process by which the nuclear envelope breaks down during cell division is called:

Accepted Answer

Nuclear disassembly

Answer

Karyokinesis

Answer

Cytokinesis

Answer

Karyorrhexis

Question 7

The structure within the nucleus that forms during mitosis to organize and segregate chromosomes is called the:

Accepted Answer

Spindle apparatus

Answer

Centrosome

Answer

Nucleolus

Answer

Nuclear envelope

Question 8

Which component provides structural support to the nuclear envelope?

Accepted Answer

Nuclear lamina

Answer

Ribosomes

Answer

Golgi apparatus

Answer

Mitochondria

Question 9

What elements constitute the chromatin fiber?

Accepted Answer

DNA and histones

Answer

RNA and histones

Answer

DNA and lipids

Answer

RNA and proteins

Question 10

Which nuclear region synthesizes ribosomes?

Accepted Answer

Nucleolus

Answer

Nuclear matrix

Answer

Nuclear lamina

Answer

Chromosomes

Question 11

Gene expression involves:

Accepted Answer

Transcription and translation

Answer

Translation and replication

Answer

Replication and transcription

Answer

Transcription only

Question 12

Which enzyme unwinds the DNA double helix during transcription?

Accepted Answer

Helicase

Answer

RNA polymerase

Answer

Ligase

Answer

Primase

Question 13

The nuclear pore complex enables the exchange of:

Accepted Answer

Molecules between the nucleus and cytoplasm

Answer

Ions between the nucleus and cytoplasm

Answer

Proteins between the nucleus and cytoplasm

Answer

Only RNA between the nucleus and cytoplasm

Question 14

Which type of cell division results in two genetically identical daughter cells?

Accepted Answer

Mitosis

Answer

Meiosis

Answer

Binary fission

Answer

Budding

Question 15

Which protein binds to centromeres and facilitates chromosome segregation?

Accepted Answer

Cohesin

Answer

Kinesin

Answer

Myosin

Answer

Actin

Question 16

What is the primary function of chromatin?

Accepted Answer

Storage and expression of genetic information

Answer

Protein synthesis

Answer

Ribosome assembly

Answer

RNA processing

Question 17

Which of the following is NOT a primary function of the nucleolus?

Accepted Answer

Protein translation

Answer

Ribosome assembly

Answer

rRNA synthesis

Answer

Formation of nuclear lamina

Question 18

What are the thread-like structures visible in the nucleus during cell division called?

Accepted Answer

Chromosomes

Answer

Chromatin

Answer

Nucleoli

Answer

Ribosomes

Question 19

Which enzyme is responsible for separating the DNA strands during transcription initiation?

Accepted Answer

Helicase

Answer

RNA polymerase

Answer

Ligase

Answer

Topoisomerase

Question 20

What is the primary protein component of the nuclear pore complex?

Accepted Answer

Nucleoporins

Answer

Histones

Answer

Nuclear lamina

Answer

Cytosol

Question 21

Which of the following is NOT one of the three main types of RNA polymerase?

Accepted Answer

RNA polymerase IV

Answer

RNA polymerase I

Answer

RNA polymerase II

Answer

RNA polymerase III

Question 22

Which enzyme extends the 3' overhangs of telomeres?

Accepted Answer

Telomerase

Answer

Helicase

Answer

Ligase

Answer

Topoisomerase

Question 23

What is the process called by which the nucleus divides into two genetically identical daughter nuclei?

Accepted Answer

Mitosis

Answer

Meiosis

Answer

Cytokinesis

Answer

Karyokinesis

Question 24

The nucleus's shape and stability are primarily maintained by which structural component?

Accepted Answer

Nuclear envelope

Answer

Nuclear matrix

Answer

Nucleolus

Answer

Chromatin

Question 25

Identify the principal molecular component of chromatin:

Accepted Answer

DNA

Answer

RNA

Answer

Protein

Answer

Carbohydrate

Question 26

Which of the following processes is a primary function linked to the nucleolus?

Accepted Answer

Ribosome synthesis

Answer

Protein degradation

Answer

DNA replication

Answer

Lipid metabolism

Question 27

The mechanism by which the nuclear envelope controls substance exchange between the nucleus and cytoplasm is:

Accepted Answer

Through nuclear pores

Answer

By active transport

Answer

By passive diffusion

Answer

Exclusively through endocytosis

Question 28

Which enzyme plays a role in modifying the structure of chromatin?

Accepted Answer

Histone acetyltransferase

Answer

RNA polymerase

Answer

DNA helicase

Answer

Proteasome

Question 29

Chromatin is composed of:

Accepted Answer

DNA, histones, and non-histone proteins

Answer

DNA and histones only

Answer

RNA and histones

Answer

RNA and non-histone proteins

Question 30

Which structure within the nucleus is responsible for synthesizing ribosomal subunits?

Accepted Answer

Nucleolus

Answer

Nuclear envelope

Answer

Chromatin

Answer

Nuclear lamina

Question 31

During mitosis, the nuclear envelope:

Accepted Answer

Disassembles and then reassembles

Answer

Remains intact throughout the process

Answer

Partially disassembles, but remains in place

Answer

Completely disassembles and does not reform

Question 32

Which of the following is a characteristic of euchromatin?

Accepted Answer

Loosely packed and transcriptionally active

Answer

Tightly packed and transcriptionally inactive

Answer

Contains only non-coding DNA

Answer

Found only in prokaryotic cells

Question 33

Which of the following is a key event that occurs during interphase of the cell cycle?

Accepted Answer

DNA replication

Answer

Chromosome condensation

Answer

Nuclear envelope breakdown

Answer

Spindle fiber formation

Question 34

Which of the following proteins is responsible for unwinding DNA during transcription?

Accepted Answer

Helicase

Answer

RNA polymerase

Answer

Primase

Answer

Topoisomerase

Question 35

The process by which RNA is synthesized from a DNA template is called:

Accepted Answer

Transcription

Answer

Replication

Answer

Translation

Answer

Reverse transcription

Question 36

Which component of the nuclear pore complex allows molecules to pass through the nuclear envelope?

Accepted Answer

Nucleoporins

Answer

Histones

Answer

Ribosomes

Question 37

Which structure encloses the nuclear material and regulates material exchange with the cytoplasm?

Accepted Answer

Nuclear envelope

Answer

Chromatin

Answer

Nucleolus

Answer

Centrosome

Question 38

Which molecule constitutes chromatin and plays a vital role in gene regulation?

Accepted Answer

DNA

Answer

RNA

Answer

Protein

Answer

Lipid

Question 39

What is the primary function of the nucleolus?

Accepted Answer

Ribosome production

Answer

RNA processing

Answer

Protein synthesis

Answer

Mitochondrial biogenesis

Question 40

Which enzyme unwinds chromatin during gene transcription?

Accepted Answer

Helicases

Answer

RNA polymerase

Answer

Topoisomerases

Answer

DNA ligase

Question 41

What structure segregates chromosomes during cell division?

Accepted Answer

Spindle apparatus

Answer

Nuclear envelope

Answer

Centrosome

Answer

Ribosome

Question 42

Which protein regulates gene expression by interacting with specific DNA sequences?

Accepted Answer

Transcription factors

Answer

Histones

Answer

RNA polymerase

Answer

DNA methyltransferases

Question 43

Which cell cycle checkpoint monitors proper chromosome attachment to the spindle apparatus?

Accepted Answer

Metaphase checkpoint

Answer

G1 checkpoint

Answer

G2 checkpoint

Answer

S checkpoint

Question 44

Which technique visualizes the nucleus and its components in cells?

Accepted Answer

Fluorescence microscopy

Answer

Electron microscopy

Answer

X-ray diffraction

Answer

Mass spectrometry

Question 45

Which RNA type is produced by RNA polymerase I?

Accepted Answer

rRNA

Answer

mRNA

Answer

tRNA

Answer

snRNA

Question 46

During DNA replication, which enzyme is responsible for unwinding the DNA double helix to facilitate the synthesis of new strands?

Accepted Answer

Helicase

Answer

Ligase

Answer

Primase

Answer

Topoisomerase

Question 47

Chromatin is composed of:

Accepted Answer

DNA and histone proteins

Answer

RNA and histone proteins

Answer

RNA and non-histone proteins

Answer

DNA and non-histone proteins

Question 48

The primary function of the nucleolus is to assemble:

Accepted Answer

Ribosomes

Answer

RNA

Answer

DNA

Answer

Proteins

Question 49

Which of the following is a function of the nuclear lamina?

Accepted Answer

Provides structural support and shape

Answer

Facilitates DNA replication

Answer

Transports materials into the nucleus

Answer

Regulates gene expression

Question 50

Within the nucleus, the site of RNA polymerase II transcription is primarily the:

Accepted Answer

Chromatin

Answer

Nuclear envelope

Answer

Nuclear matrix

Answer

Nucleolus

Question 51

Nuclear pore complexes primarily facilitate:

Accepted Answer

Selective exchange of molecules between the nucleus and cytoplasm

Answer

Degradation of nuclear material

Answer

Transport of genetic material out of the nucleus

Question 52

Which histone is NOT part of the nucleosome structure?

Accepted Answer

H1

Answer

H2A

Answer

H2B

Answer

H3

Question 53

The process by which a cell divides its nuclear genetic material into two identical sets of chromosomes is known as:

Accepted Answer

Mitosis

Answer

Transcription

Answer

Meiosis

Answer

Replication

Question 54

Which of the following describes a characteristic of heterochromatin?

Accepted Answer

Transcriptionally inactive

Answer

Contains actively transcribed genes

Answer

Found only in the nucleolus

Answer

Uncoiled and accessible for transcription

Question 55

The organelle widely recognized as the control center of the cell, regulating gene expression and cell division, is the:

Accepted Answer

Nucleus

Answer

Lysosome

Answer

Cytoplasm

Answer

Golgi apparatus