Plasmodesmata are connections between adjacent cells. Plasmodesmata are narrow channels that act as intercellular cytoplasmic bridges to facilitate communication and transport of materials between plant cells. Plasmodesmata are formed during cell division, when trace of the endoplasmic reticulum become caught in the new wall that divides the parent cell.
Which of the following statements support the cell theory?
Cells can be cultured by tissue culture supports the statement that cells arise from pre-existing cells.
The function of centriole is
During cell division spindle fibres are formed by centriole.
Membrane surrounding vacuole is called :
Tonoplast also shows fluid mosaic model and is similar to plasma membrane.
Choose the incorrect match.
Protein synthesis takes place in ribosomes, which are attached to surface of endoplasmic reticulum by ribophorin-I and ribophorin-II. About 50 hydrolytic enzymes are found in the lysosome. These include proteases, nucleases, glycosidases, lipases, phospholipases, phosphatases and sulphatases. All lysosomal enzymes are acid hydrolases and optimally active at pH-5.0
DNA which is present above the secondary constriction is called____.
Repeated sequences of DNA which is present above the secondary constriction is called the satellite DNA.
How are cells formed?
Cells are formed from pre existing cells by the process of cell division which could be amitosis,mitosis or meiosis.
Cell wall shows
Cell wall shows complete permeability because it helps in the transport of substances in and out of the cell.
The latest model for plasma membrane is
Fluid mosaic model is the most recent of a biomembrance proposed by Singer and Nicolson(1972,74).
Microtubules absent in
Microtubules are formed of dimers of tubulin. Microtubules are present in centriole, flagella, spindle fibres but not in mitochondria.
Fluid mosaic model of cell membrane was put forward by
Fluid mosaic model of cell membrane was put forward by Singer and Nicolson.
Who proposed the theory that "cells arise only from the pre-existing cells"?
Virchow gave 'Omnis cellula a cellula' theory.
Lysosomes have a high content of
Lysosomes are single membrane bound vesicular organelles rich in acid hydrolases. They are involved in phagocytosis.
The cytoskeleton in cells is composed of ____.
Cytoskeleton is made of an elaborate network of proteinaceous microtubules.
Resolution power is the ability to
The ability to distinguish two close objects is called resolution power.
Mitochondria divide by the process of ____.
Mitochondria divide by the process of fission.
"Power house" of the cell is called :
Power house of the cell is mitochondria as it is the site for oxidation of food material (cellular respiration) to release energy.
Which of the following is not true regarding the pili?
Pili have no role to play in motility. It is the flagella which helps in movement.
The function of rough endoplasmic reticulum is
Rough endoplasmic reticulum bears ribosomes on its outer surface. These ribosomes take part in protein synthesis.
Nucleoproteins are synthesised in
Nucleoproteins are conjugated proteins. They are deoxyribonucleoproteins and ribonucleoproteins synthesised in cytoplasm of the cell.
The main function of the Golgi apparatus is____.
The main function of the Golgi apparatus is to package the materials like proteins prepared by the ER.
Which one of the following is not considered as a part of the endomembrane system ?
Polar molecules cannot pass through the nonpolar bilayer , so they require carrier protein to facilitate their transport across the membrane.
Lysosomes sre synthesised by____.
Lysosomes are vesicular structures which are formed by the process of packaging in the Golgi apparatus.
What is required for osmosis to occur?
Osmosis requires a solute concentration gradient.It is a passive process and does not require ATP. Enzymes are also not required for this process.
Chromosomes, having equal arms are called
Metacentric chromosomes are 'V' shaped in which centromere is situated in the mid portion of chromatids.
The site for ribosome synthesis is ____.
The nucleolus is the site for active ribosomal RNA synthesis.
Cytoskeleton is made up of:
The Cytoskeleton is made up of three kinds of ptotein flaments actin flaments (also called microfilaments), intermediate filaments, and microtubules whose major constituents are tubulin protein.
Green pigment (Chlorophyll) present in plants is
The green colour of plants is due to chlorophyll, which is found in chloroplast.
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