Tag: organelles in cell

Questions Related to organelles in cell

The nucleus possessed the ability to control phenotype was first determined by

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

  1. Experiments with radiolabelled phages

  2. Experiments with bacteria that identified DNA polymerase

  3. Transformation experiments with Streptococcus pneumoniae

  4. Identification of restriction endonucleases

  5. Grafting experiments with Acetabularia

Show answer
Correct Option: E
Explanation:

Acetabularia consists of a rootlike holdfast, a long, cylindrical stalk; and a cuplike cap. The nucleus is present in the holdfast. Acetabularia exhibits regeneration of the cap after any injury. A. mediterranea has a smooth cap and A. crenulata, has a cap with fingerlike projections. Danish biologist J. Hämmerling and Belgian biologist J. Brachet performed grafting experiment on above mentioned species and showed that type of caps that regenerated were determined by the type of the donor species of the holdfasts, not by those donating the stalks. It was concluded, that nucleus in the holdfast of Acetabularia controls the shape of the caps. The correct answer is E.

All of the following organelles are associated with an endomembrane except

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

  1. Nucleus

  2. Vesicles

  3. Golgi apparatus

  4. Endoplasmic reticulum

  5. Plasma membrane

Show answer
Correct Option: A
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.

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

  1. A

  2. B

  3. C

  4. D

Show answer
Correct Option: C
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. 

Pick the odd one out giving the suitable reasons.

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

  1. Nucleus

  2. Nucleolus

  3. Chromosome

  4. Ribosome

Show answer
Correct Option: D
Explanation:
Ribosomes and chromosomes. A ribosome is a component of cells that synthesizes protein chains.

Karyology is the study of

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

  1. Cytoplasm

  2. Cell

  3. Mitochondria

  4. Nucleus

Show answer
Correct Option: D
Explanation:
  • A karyotype is the number and appearance of chromosomes in the nucleus of a eukaryotic cell. The term is also used for the complete set of chromosomes in a species or in an individual organism. The study of whole sets of chromosomes is sometimes known as karyology. Hence, the karyology is the study of the nucleus.
  • So, the correct answer is 'nucleus'.

Role of nucleus in morphological differentiation was discovered in _______________.

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

  1. Acetabularia by Hammerling

  2. Drosophila by Morgan

  3. Neurospora by Beadle and Tatum

  4. Garden Pea by Mendel.

Show answer
Correct Option: A
Explanation:

Answer is option (A) Acetabularia by Hammerling.

In his experiments, Hammerling grafted the stalk of one species of Acetabularia onto the foot of another species.
In all cases, the cap that eventually developed on the grafted cell matched the species of the foot rather than that of the stalk.
 In this example, the cap that is allowed to grow on the grafted stalk looks like the base species one... A. mediterranea
This experiment shows that the base is responsible for the type of cap that grows. The nucleus that contains genetic information is in the base, so the nucleus directs cellular development.



















Nucleus was discovered by

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

  1. Purkinje

  2. Nageli

  3. Robert Brown

  4. Hofmeister

Show answer
Correct Option: C
Explanation:
  • A 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.
  • Within the nucleus, 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.
  • It was discovered by Robert Brown in the year 1831.
  • So, the correct answer is 'Robert Brown'.

Function of the cell is controlled by

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

  1. Protoplasm

  2. Cytoplasm

  3. Nucleolus

  4. Nucleus

Show answer
Correct Option: D
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'.

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

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

  1. Chromatin

  2. Fibrous lamina

  3. Nuclear lamina

  4. Both B and C.

Show answer
Correct Option: D
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.'

Nucleus is covered by

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

  1. Porous double membrane

  2. Porous single membrane

  3. Non-porous single membrane

  4. Non-porous double membrane

Show answer
Correct Option: A
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'.