The cell theory was given in year 1839 by Schleiden and Schwann. According to this theory all organisms are composed of cell and cells are the basic unit of life.
How did this theory help in the field of science?
It helped to study the working of cells.
It helped in curing diseases caused by cell.
It helped in restating the earlier theories on cell.
It helped in introducing the use of microscopes to study cell.
Correct Answer :
A. It helped to study the working of cells.
Cell theory explains the general principles of construction for all living things by focusing on studying the working of cells. The use of microscopes to study cell was in practice way before the cell theory was formulated.
Related Questions
Basal bodies are associated with the formation of
phragmoplast
cilia and flagella
cell plate
kinetochore
The following diagram represents a structure chromosome.
Identify the structures marked as A, B and C.
A - Satellite, B - Primary constriction, C - Acrocentric
A - Satellite, B - Secondary constriction, C - Metacentric
A - Satellite, B - Centromere, C - Telocentric
A - Satellite, B - Centromere, C - Submetacentric
Axoneme with 9 + 2 microtubular arrangement occurs in
cilia
flagella
both (a) and (b)
centriole
Select the incorrect statement about prokaryotic ribosomes.
50S and 30S subunits unite to form 70S ribosomes.
Polysome/polyribosome consists of many ribosomes only.
Ribosome is the site of protein synthesis.
Polysome indicate the synthesis of identical poolypeptide in multiple copies.
Match column-I with column-II and choose the correct option.
| Column-I | Column-II |
|---|---|
| A. Tonoplast | I. Contain digestive enzyme |
| B. Contractile vacuole | II. Store metabolic gases |
| C. Food vacuole | III. Excretion |
| D. Air vacuole | IV. Transport of ions in plants |
A IV; B III; C I; D II
A II; B III; C IV; D I
A IV; B II; C III; D I
A I; B III; C II; D IV
Which of the following statement of a bacterial cell is/are correct?
- Mesosome is formed by the extensions of plasma membrane into the cell.
- The pili are elongated tubular structures made up of a protein.
- Flagellum is composed of filament, hook and basal body.
- Ribosomes are about 30 nm by 50 nm in size.
(i), (ii), (iii)
All of the above
(ii) & (iv)
None of the above
Cell sap is a
living content of cytoplasm.
nonliving content of cytoplasm.
nonliving content of vacuole.
living content of vacuole.
Which of the following statement is correct regarding vacuole?
It is membrane-bound and contains storage proteins and lipids.
It is membrane-bound and contains water and excretory substances.
It lacks membrane and contains air.
It lacks membrane and contains water and excretory substances.
Protein synthesis in an animal cell occurs
on ribosomes present in cytoplasm as well as in mitochondria.
on ribosomes present in the nucleolus as well as in cytoplasm.
only on ribosomes attached to the nuclears envelope and endoplasmic reticulum.
only on the ribosomes present in cytosol.
Which of the following pair are correctly matched ?
(I) Amyloplasts Store proteins
(II) Mitochondrion Power house of the cell
(III) Stroma Chlorophyll pigment
(IV) Axoneme 9 + 2 array
(I) and (III) only
(II), (III) and (IV) only
(III) and (IV) only
(II) and (IV) only
Choose the wrong statements regarding bacterial cell
- Glycocalyx is the outermost envelope in bacteria.
- The glycocalyx could be a loose sheath called capsule.
- The glycocalyx may be thick and tough called slime layer.
- A special structure formed by the plasma membrane is called mesosome.
- Small bristle like fibres sprouting out of the cell are called fimbriae.
(i) and (iii)
(i) and (ii)
(ii) and (iii)
(i) and (iv)
Match the items given in column-I with their role given in column-II and choose the correct option.
| Column-I | Column-II |
|---|---|
| A. SER | I. Increase the surface area |
| B. Golgi apparatus | II. Store oils or fats |
| C. Cristae | III. Excretion |
| D. Peroxisome | IV. Photorespiration |
| E. Elaioplasts | V. Synthesis of lipid |
A V; B III; C I; D IV; E II
A V; B III: C II; D IV; E I
A II; B III; C I; D IV; E V
A III; B IV; C I; D V; E II
Function of RER is
autolysis
protein synthesis
lipid synthesis
carbohydrate synthesis
The figure below shows the structure of a mitochondrion with its four parts labelled (A), (B), (C) and (D).
Select the part correctly matched with its function.
Part (D): Outer membrane Gives rise to inner membrane by splitting.
Part (B): Inner membrane Forms infoldings called cristae.
Part (C): Cristae Possess single circular DNA molecule and ribosomes.
Part (A): Matrix Major site for respiratory chain enzymes.
Identify the components labelled as A, B, C, D and E in the diagram given below from the list (i) to (viii).
- Cristae of mitochondria
- Inner membrane of mitochondria
- Cytoplasm
- Smooth endoplasmic reticulum
- Rough endoplasmic reticulum
- Mitochondrial matrix
- Ribosome
- Nucleus
A - (viii), B - (v), C - (vii), D - (iii), E - (iv)
A - (i), B - (iv), C - (vii), D - (vi), E - (iii)
A - (vi), B - (v), C - (iv), D - (vii), E - (i)
A - (v), B - (i), C - (iii), D - (ii), E - (iv)
Which of the following statements is/are correct ?
- The shape of the cells may vary with the function they perform.
- Human RBC is about 7.0 ??m in diameter.
- Cytoplasm is the main area of cellular activities.
- Various chemical reactions occur in cytoplasm to keep the cell in the living state.
(i), (ii), (iii) and (iv)
Only (i) and (ii)
Only (iv)
None of the above
Centrifugation of a cell results in the rupture of the cell membrane and the contents compacting into a pellets in the bottom of the centrifuge tube. Bathing this pellet with a glucose solution yields metabolic activity including the production of ATP. One of the contents of this pellet is most likely which of the following?
Cytosol
Mitochondria
Lysosomes
Golgi bodies
In which of the following the cells are held together by a Ca-pectate layer?
Primary cell wall
Secondary cell wall
Middle lamella
Tertiary cell wall
Given below are some characters of a cell organelle identify the correct organelle which shows all the characters described above.
- It is a membrane bound space found in the cytoplasm.
- It is bound by a single membrane called tonoplast.
- It contains water, sap, excretory products and other materials not useful to the cell.
- It has higher concentration of sap than the cytoplasm.
Golgi apparatus
Lysosomes
Endoplasmic reticulum
Vacuoles
Match column-I (scientists) with column-II (discovery) and select the correct option.
| Column-I | Column-II |
|---|---|
| A. Leeuwenhoek | I. First saw and described a living cell |
| B. Robert Brown | II. Presence of cell wall is unique to plant cells |
| C. Schleiden | III. Discovered the nucleus |
| D. Schwann | IV. All plants are composed of different kind of cells |
A I, B III, C IV, D II
A I, B III, C II, D IV
A III, B I, C IV, D II
A I, B IV, C II, D III
Difference between the prokaryotic and eukaryotic cells in having
cell wall
nuclear membrane
ribosome
none of these
Microtubules are absent in
mitochondria
centriole
flagella
spindle fibres
Study the following statements on cilium or flagellum and answer the question.
- Cilium / Flagellum contains an outer ring of nine doublet microtubules surrounding two singlet microtubules.
- Cilia are smaller which work like oars, causing the movement of either the cells or surrounding fluid.
- Flagella are comparatively longer and responsible for cell movement.
- Cilium and flagellum are covered with plasma membrane.
Which of the above statements are correct?
(i) and (ii)
(i), (ii), (iii) and (iv)
(i) and (iv)
(ii) and (iii)
According to widely accepted fluid mosaic model cell membranes are semi-fluid, where lipids and integral proteins can diffuse randomly. In recent years, this model has been modified in several respects. In this regard, which of the following statements is incorrect?
Proteins in cell membranes can travel within the lipid bilayer.
Proteins can also undergo flip-flop movements in the lipid bilayer.
Proteins can remain confined within certain domains of the membrane.
Many proteins remain completely embedded within the lipid bilayer.
_______________ is the important site of formation of glycoproteins and golycolipids.
SER
Lysosome
Golgi apparatus
Mitochondria
Which one of the following is not considered as part of the endomembrane system?
Golgi complex
Peroxisome
Vacuole
Lysosome
The best way to identify a cell as either prokaryotic or eukaryotic is to determine whether
it came from a single-celled or multicellular organism.
it has a nucleus.
it has a plasma membrane.
it has cytosol.
Plastids are found in
all animal cells.
some animal cells.
all plant cells.
all plant cells and euglenoides.
Which one of the following combination is mismatched?
Glycocalyx May be capsule or slime layer
Pili Reproduction
Cell wall Protective, determines shape, prevents from bursting
Flagella, pili and fimbriae Surface structures of bacterial cell
The given figures show two types of cell. Which structures are common to both the cells?
Nucleus and cell wall
Nucleus and cytoplasm
Ribosomes and flagella
Ribosomes and cell wall