Biology · Science General

Cell Biology and Structure

3,221 Questions

Cell biology focuses on the structure and function of cellular organelles. Key topics include cellular respiration, DNA inheritance, and energy production. These fundamental biology concepts are crucial for medical entrance and state service examinations.

Cell organelles functionsCellular respiration sitesDNA and ribosomesAnimal cell structurePlant cell components

Cell Biology and Structure Questions

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Which of the following would not be considered part of a cell's cytoplasm? 

  1. Ribosome

  2. Nucleus

  3. Mitochondrion

  4. Microtubule
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The nucleus is the largest and important part of the cell. It surrounded by the two layers of membrane. These membranes separates the nuclear content to get mixed with cytoplasm. Cytoplasm is the proteinaceous fluid in the cell which holds organelles like ribosomes, mitochondria, ER etc. Thus, the correct answer is option B.

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

The nucleus is separated from surrounding cytoplasm by a nuclear envelope which is 

  1. Single and porous

  2. Double and porous

  3. Single and non-porous

  4. Double and non-porous
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A nuclear membrane, also known as the nuclear envelope, is a double lipid bilayer membrane, which surrounds the nucleus containing genetic material and nucleolus in eukaryotic cells. The nuclear membrane consists of two lipid bilayers- the inner nuclear membrane and the outer nuclear membrane and consists pores called as nuclear pores for the transportation of DNA, RNA and proteins. Thus, the correct answer is option B.

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Nucleus of a cell

  1. Contains ribosomes

  2. Contains the genetic material

  3. Contains Golgi body

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The nucleus controls the functioning of a cell. It is generally located in the center of the cell and is spherical in shape. It has a double-walled membrane which separates it from the cytoplasm. It contains the genetic material DNA and RNA in it. This porous membrane allows the transfer of material in the nucleus and cytoplasm. The nucleus contains a dense body called as nucleolus, which actually contains chromosomes, the genetic material. 

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

.......... is the control centre of the cell.

  1. Nucleus

  2. Mitochondria

  3. Lysosome

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The nucleus is the membrane bound important structure of the cell. Nucleus regulates all the cellular activities by controlling the enzymes required for cellular processes. Enzymes are proteins and protein synthesis is controlled by nucleus as mRNA required for protein synthesis is made from DNA which is situated in the nucleus. It controls all the cellular activities and thus, called as brain of the cell.

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Which one of the following contains the genetic material of a eukaryotic cell?

  1. Golgi apparatus

  2. Mitochondria

  3. Nucleolus

  4. Nucleus
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Golgi apparatus is an organelle present in the cell and structurally possess series of compartments. Golgi apparatus has the main function of modifying, sorting and packaging the proteins which are synthesized by cells. Golgi bodies are also involved in the transport of lipid molecules across the cell. Golgi bodies also create lysosomes.  
Mitochondria produce the energy in the form of ATP of the cell. It consists its own DNA and called as mitochondrial DNA and not the DNA of the cell.
The nucleolus is the largest structure present in the nucleus. Ribosome synthesis and assemblage occurs in nucleolus region. The nucleus is bound with the double membrane in a eukaryotic cell in which most of the genetic material is present. The genetic material contains DNA and RNA. Thus, the correct answer is option D.

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

The nucleus has a double layered covering called as

  1. Cell membrane

  2. Cytoplasmic membrane

  3. Nuclear membrane

  4. Capsule
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A eukaryotic cell has a nucleus bounded by a double wall membrane structure known as a nuclear membrane. The nuclear membrane is a discontinuous membrane having nuclear pores, which act as a protein channel for regulating the exchange of materials between cytoplasm and nucleoplasm. The gap between the inner and outer membrane is known as perinuclear space.

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

................ is present inside the nucleus of a cell.

  1. Mitochondrion

  2. Ribosome

  3. Endoplasmic reticulum

  4. Chromatin

  5. Centriole
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chromatin is a complex of DNA and proteins that form chromosomes within the nucleus of eukaryotic cells. Nuclear DNA does not appear in free linear strands. 

It is highly condensed and wrapped around nuclear proteins in order to fit inside the nucleus. 
So option D is correct. 

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Cell nucleus is the site for

I. RNA synthesis 
II. Proteins synthesis 
III. DNA synthesis

  1. I only

  2. II only

  3. III only

  4. I and III only

  5. I, II and III
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The nucleus is the important structure of the cell and fully enclosed in a nuclear membrane. It contains the cells' genetic material organized as DNA and variety of proteins to form chromosomes. This is major site for cell reproduction. The genes are first transcribed, where DNA is read by RNA polymerase to produce messenger RNA (mRNA). The nucleus is therefore the site of RNA and DNA synthesis. Whereas protein is synthesized from the mRNA in the cytoplasm. Thus, the correct answer is option D.

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

All of the following organelles are associated with an endomembrane except

  1. Nucleus

  2. Vesicles

  3. Golgi apparatus

  4. Endoplasmic reticulum

  5. Plasma membrane
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The eukaryotic endomembrane system has a nuclear membrane, endoplasmic reticulum, Golgi apparatus, plasma membrane and various small vesicles which are constantly reorganized and serve to segregate specific metabolic processes and to provide surfaces for enzyme-catalyzed reactions.
So, the correct answer is option A.

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Abhi conducted an experiment to investigate what would happen when different cell organelles of a balsam plant leaf are removed. The results are recorded in the table given.

Cell parts Out comes
P The cell cannot function properly.
Q Iodine solution remains yellowish brown.
R The cell cannot control the entry and exit of the substances.
S The cell loses its regular shape

Identify the cell parts P, Q, R and S.

(P) (Q) (R) (S)
(A) Nucleus Chloroplast Cell wall Cytoplasm
(B) Cytoplasm Chloroplast Nucleus Cell membrane
(C) Nucleus Chloroplast Cell membrane Cell wall
(D) Nucleus Chloroplast Cell wall Cell membrane

  1. A

  2. B

  3. C

  4. D
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The label P is the nucleus is the controlling centre of the cell. All the activities of the cell are controlled and regulated by the nucleus and the cell cannot function properly in the absence of this organelle. 
The label Q is the chloroplast which is responsible for making food in the form of starch which turns the iodine solution to bluish black. In the absence of chloroplast, the solution remains yellowish brown.
The label R is the cell membrane which controls the entry and the exit of the molecules.
The label S refers to the cell wall which maintains the shape of the cell.
Thus, the correct answer is option C. 

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Function of the cell is controlled by

  1. Protoplasm

  2. Cytoplasm

  3. Nucleolus

  4. Nucleus
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Nucleus is a membrane-bound organelle containing the genetic material in the form of DNA molecule coiled to form the chromosomes.
  • It is also known as the control centre of the cell.
  • The DNA molecule gets transcribed into an mRNA template which is translated into a variety of proteins. 
  • These translated proteins help in performing all the important functions within the cell.
  • So, the answer is 'Nucleus'.
Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Dense fibrous complex lying adjacent to inner membrane of nuclear envelope is

  1. Chromatin

  2. Fibrous lamina

  3. Nuclear lamina

  4. Both B and C.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • The nuclear membrane or karyotheca is a double membrane having pores at intervals.
  • The nuclear membrane on its inside has a supporting membrane called the nuclear lamina or the fibrous lamina having a uniform thickness.
  • It is a dense network of fibres present inside the nucleus of cells and are made up of intermediate filaments and membrane-associated proteins.
  • It provides mechanical support to the nucleus and also regulates DNA replication and cell division 
  • So, the correct answer is 'Both B and C.'
Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Nucleus is covered by

  1. Porous double membrane

  2. Porous single membrane

  3. Non-porous single membrane

  4. Non-porous double membrane
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • A nucleus is a membrane-bound organelle containing the genetic material in the form of DNA molecule coiled to form the chromosomes.
  • The nuclear membrane or the nuclear envelope is a lipid bilayer membrane (porous double-membrane) that encloses the nucleus.
  • Nuclear membranes have protein-based channels known as nuclear pores which allow the transport of molecules across the nuclear envelope.
  • So, the correct answer is 'Porous double membrane'.
Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Nucleoplasm is also called

  1. Nuclear sap

  2. Karyolymph

  3. Both A and B

  4. Nuclear matrix
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Nucleoplasm refers to the soluble materials present within the nucleus that is enclosed by the nuclear envelope.
  • It is made up of enzymatic proteins (for replication of DNA and transcription RNA), ribonucleoproteins, enzymes, ions etc.
  • It is also known as karyolymph or nuclear sap.
  • So, the correct answer is 'Both A and B'.