Who proposed the theory that Cells arise only from the pre-existing cells?
Mohl
Virchow
Haeckel
Brown
Correct Answer :
B. Virchow
Rudolf Virchow (1855) first explained that cells divided and new cells are formed from pre-existing cells (omnis cellula-ecellula). It is also know as law of cell lineage.
Related Questions
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.
Which one of the following pairs is not correctly matched?
Cristae The tubular structure formed by the folding of the inner membrane of the mitochondrion.
Plasmodesmata The membrane surrounding the vacuole in plants.
Grana Membrane bound discs in chloroplasts that contain chlorophylls and carotenoids.
Middle lamella Layer between adjacent cells walls in plants derived from cell plate.
Match column I (cell type) with column II (size) and choose the correct option.
| Column-I | Column-II |
|---|---|
| (Cell type) | (Size) |
| A. Viruses | I. 1-2 ??m |
| B. PPLO | II. 10-20 ??m |
| C. Eukaryotic cell | III. About 0.1 ??m |
| D. Bacterium | IV. 0.02 - 0.2 ??m |
A I, B II, C III, D IV
A IV, B III, C II, D I
A I, B III, C II, D IV
A IV, B II, C III, D I
Which one of the following is not considered as part of the endomembrane system?
Golgi complex
Peroxisome
Vacuole
Lysosome
Basal bodies are associated with the formation of
phragmoplast
cilia and flagella
cell plate
kinetochore
Consider the following statements and choose the correct statement.
- The endomembrane system includes mitochondria, chloroplast and peroxisomes.
- Smooth endoplasmic reticulum is the major site for synthesis of lipid.
- Rough endoplasmic reticulum is actively involved in protein synthesis.
- Mitochondrial matrix possesses single circular DNA, a few RNA and 80S ribosomes. Of the above statements.
(i) and (iii)
(ii) and (iv)
(iii) and (iv)
(ii) and (iii)
Satellite means
terminal part of the chromosome beyond secondary constriction.
terminal part of the chromosome beyond primary constriction.
terminal part of chromosome beyond tertiary constriction.
none of the above
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.
Match column-I with column-II and select the correct option.
| Column - I | Column - II |
|---|---|
| A. RER | I. Intracellular and extracellular digestion |
| B. Cell wall | II. Provide structural support to the cell |
| C. Flagella | III. Protein synthesis and secretion |
| D. Lysosomes | IV Responsible for cell movement |
A III, B II, C IV, D I
A II, B III, C IV, D I
A I, B III, C II, D IV
A IV, B II, C III, D I
The given diagram shows the types of chromosomes (labelled as A, B, C & D) based on the position of centromere.
Which one is the correct option for the labelled chromosomes. A, B, C and D ?
A Telocentric chromosome, B Acrocentric chromosome, C Submetacentric chromosome, D Metacentric chromosome
A Acrocentric chromosome, B Telocentric chromosome, C Metacentric chromosome, D Submetacentric chromosome
A Submetacentric chromosome, B Metacentric chromosome, C Telocentric chromosome, D Acrocentric chromosome
A Metacentric chromosome, B Submetacentric chromosome, C Acrocentric chromosome, D Telocentric chromosome.
Centrioles and centrosomes occur in the cells of
green plants
animals
bacteria and cyanobacteria
both (b) and (c)
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
Which of these is wrongly matched?
Chloroplasts Chlorophyll
Elaioplasts Starch
Chromoplasts Carotenoids
Amyloplasts Carbohydrates
Polysome is a chain of
oxysomes
sphaerosomes
ribosomes
dictyosomes
What would happen if lysosomes get ruptured in a cell?
Cell dies
Cell shrinks
Cell swell up
Nothing would happen
Microtubules are absent in
mitochondria
centriole
flagella
spindle fibres
Select the statements which are related to Schwann.
- He reported that cells have a thin outer layer which is today known as plasma membrane
- Cell wall is a unique character of the plant cell.
- Body of plants and animals are composed of cells and products of cells.
Only (i)
Only (iii)
(i) and (iii)
All of these
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
Golgi apparatus is concerned with
excretion
secretion
ATP synthesis
RNA synthesis
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
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
8.A student was given cell samples (A and B) to identify parts which are highlighted. He observed the samples under the microscope and list down the function of the part of cell sample. The information collected by the student is listed in the table below, on the basis of which the student infers that the samples contain the organelles.
| Sample A | Sample B |
|---|---|
| Make energy available for cellular metabolism | Generates ATP and synthes izes s ugar |
| Absent in cell that carry oxygen throughout the body | Present in plant cell |
| Called the energy currency of cell | Source o f all the food energy |
Identify the part highlighted in the sample A and B and explain why they were called as semi-autonomous organelles?
Sample A - Mitochondria, Sample B - Chloroplast; because both the organelles are double membrane bound structure.
Sample A- Mitochondria, Sample B - Chloroplast; because they both are capable of synthesis of their own proteins only.
Sample A - Mitochondria, Sample B - Chloroplast; because they are capable of synthesis of their own proteins and contain their own DNA.
Sample A- Mitochondria, Sample B - Chloroplast; because they contain their own DNA to transfer the genetic information from one generation to another.
Most of water, in mature plant cells occurs in
nucleus
cell wall
vacuoles
cytoplasm
The cytoskeleton is a proteinaceous network of fibres in the cytoplasm. It is involved in
mechanical support.
motility.
maintenace of cell-shape.
all of the above
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 is incorrect ?
Mycoplasma is the smallest cell (0.3 �).
Bacteria are 3 to 5 �m in size.
The largest cell is the egg of an ostrich.
Nerve cells are some of the smallest cells.
Read the statements given below with regard to the functions performed by Golgi apparatus ?
- Transport and chemically modify the materials contained within it.
- Performs the function of packaging materials.
- Important site of formation of glycoproteins and glycolipids.
Which of the following is the correct answer ?
(i) is wrong but (ii) and (iii) are correct
(ii) is wrong but (i) and (iii) are correct
(ii) and (iii) are wrong but (i) is correct
All are correct.
Which of the following statements are correct ?
- In prokaryotic cells, a special membranous structure formed by the extension of the plasma membrane into the cell is known as polysome.
- The smooth endoplasmic reticulum is the major site for synthesis of glycoproteins.
- RuBisCO is the most abundant protein in the whole biosphere.
- Mitochondria, chloroplasts and peroxisomes are not considered as part of endomembrane system. Of the above statements
(iii) and (iv)
(i) and (ii)
(ii) and (iii)
(i) and (iv)
Which one of the following structures between two adjacent cells is an effective transport pathway?
Plasmodesmata
Plastoquinones
Endoplasmic reticulum
Plasmalemma
Read the folowing statements and identify the correct option.
- Contractile vacuole takes part in osmoregulation and excretion.
- Food vacuole is formed by engulfing the food particles.
- The vacuole is bound by a double membrane called tonoplast.
- Vacuole can occupy upto 90 percent of the volume of the cell.
(i) and (ii)
(ii) and (iv)
(i), (ii) and (iv)
None of the above