Important Questions (1 mark): Cell The Fundamental Unit of Life

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Besides cellulose microfibrils, the other two cell wall networks are :-


The three important cell wall networks in a plant cell are cellulosic, pectin and glycoprotein networks.
Cellulose is an important component of plant cell walls that make the plant stems, leaves and branches rigid, they are present in the form of cellulosic microfibrils (fibre-like strands) in the inner layer of primary wall.
Pectin is an essential polysaccharide present in the plant cell wall that allows the extension of a primary cell wall and in plant growth.
Hydroxyproline-rich glycoproteins form an important structural component of cell walls.
So, the correct answer is 'Pectic and glycoprotein'.


Where are the essential proteins and lipids required for cell membrane, manufactured?


The proteins and lipidsessential for building the cell membrane, are synthesized by the rough endoplasmic reticulum (RER). The ribosomes attached to the RER help in this process.


Hydrophilic chemical of cell wall is :-

Solution: Pectic acid: It is the major component of the middle lamella but is also found in the primary walls. Pectic acid is the polymer of about 100 galacturonic acid molecules. It is hydrophilic in nature. It forms salt bridges with calcium and magnesium ions. The carboxyl groups of the galacturonic acid molecules are weak acids so they can exist in negatively charged and uncharged states depending on the protonation.

Structural element of cell wall is :-


In the primary walls of growing plant cells, the glucose polymer cellulose is assembled into long microfibrils a few nanometers in diameter. The rigidity and orientation of these microfibrils control cell expansion. Therefore, cellulose synthesis is a key factor in the growth and morphogenesis of plants.
So, the correct answer is 'Microfibrils'.


Different layers of cell wall are :-


All cell walls contain two layers, the middle lamella  and the primary cell wall, and many cells produce an additional layer, called the secondary wall. The middle lamella serves as a cementing layer between the primary walls of adjacent cells. 


The first wall layer of the cell is:-


Plant cell wall consists of three layers: the primary cell wall, secondary cell wall and the middle lamella. The middle lamella - It is first layer formed during cell division. This layer is rich in pectin. It is the outermost layer, joins together adjacent plant cells and holds them together.


Plant cells are distinguishable from animal cell in containing :-

Solution: Cell wall because animal cells contain only plasma membrane while plant cells contain both plasma membrane and cell wall which helps them to withstand extreme conditions

Ripe fruits soften due to :-


Pectin is a naturally occurring heteropolysaccharide  present in the primary cell walls of plants. It is a natural fibre found in the cell walls of plants and is mainly found in the fruit skin. It is a major component of fruit cell walls that extensively modified during fruit ripening. This structural component undergoes partial solubilisation, and the loss of neutral side chains that causes ripening of the fruits.


Ribosomes contain large quantities of :-


The correct option is C.
Ribosomes are macromolecular machines, found within all living cells, that perform biological ... RNA known as ribosomal RNA as well as dozens of distinct proteins (the exact number varies slightly between species)


The glycocalyx is:-


The correct answer is B as Glycocalyx or pericellular matrix is a carbohydrate-enriched coating of glycoprotein and a glycolipid that covers the cell membranes of few bacteria, epithelial cells and other cells.


Which of the following organelles lack membranes ?


Following are the cell organelles that are not bounded by the unit membrane:
Ribosomes, Cytoskeletal structures, Centrioles, Basal bodies, Cilia and flagella.


eRF1 is the release factor in eukaryotes that requires 


The correct option is Option B.
Termination of translation in eukaryotes is governed by two polypeptide chain release factors, eRF1 and eRF3 on the ribosome. eRF1 promotes stop-codon-dependent hydrolysis of peptidyl-tRNA, and eRF3 interacts with eRF1 and stimulates eRF1 activity in the presence of GTP. Here, we have demonstrated that eRF3 is a GTP-binding protein endowed with a negligible, if any, intrinsic GTPase activity that is profoundly stimulated by the joint action of eRF1 and the ribosome. Separately, neither eRF1 nor the ribosome display this effect. Thus, eRF3 functions as a GTPase in the quaternary complex with ribosome, eRF1, and GTP. From the in vitro uncoupling of the peptidyl-tRNA and GTP hydrolyses achieved in this work, we conclude that in ribosomes both hydrolytic reactions are mediated by the formation of the ternary eRF1-eRF3-GTP complex. eRF1 and the ribosome form a composite GTPase-activating protein (GAP) as described for other G proteins.


When did J.E Purkinje coin the term "protoplasm"?


Purkinje coined the term protoplam in 1839 for plant sap which is living fluid inside the cell. Initially Dujardin in 1835 observed the living juice inside the animal cell.


A unit of protoplasm having a nucleus and covered by plasmalemma is called :-


A cytoplast is a medical term which is defined as cell membrane plus cytoplasm. It is occasionally used to describe a cell in which the nucleus has been removed. 
Protoplasm = Cytoplasm + Nucleoplasm. 
Protoplast = Protoplasm + Plasma membrane.


The term cytoplasm was coined by :-


Cytoplasm refers to the living the material or the protoplast within a cell excluding the nucleus.
The term cytoplasm was coined by Eduard Strasburger in the year 1882.
So, the correct answer is 'Strasburger'.


Which of the following is correct for prokaryotic ribosome :-


Ribosomes are naked ribonucleoprotein particles found in both prokaryotic and eukaryotic cells. The ribosomes of prokaryotic cells are of 70S type, made up of two subunits - 30S and 50S. In an eukaryotic cell, the ribosomes present outside the cell organelles are of 80S type. They are made up of two subunits 40S and 60S.  
The 70S ribosome is made up of 3 molecules of RNA - 16S RNA in 30S subunit and 23S and 5S RNA in 50S subunit.
The 80S ribosome is made up of 4 molecules of RNA - 18S in 40S subunit and 28S, 5.8S and 5S in 60S subunit.
So, the correct answer is 'It dissociates into 30S and 50S subunits'.


Golgi apparatus takes part in synthesis of :-


The correct option is Option D. 
Golgi apparatus is a cellular organelle which consists of folded and flattened membranes within the cytoplasm.
It helps in modifying, sorting and packaging of proteins for secretion and also helps in the transportation of lipid and forms lysosomes. 
Proteins and lipids synthesised by the endoplasmic reticulum combine with carbohydrates to form glycoproteins and glycolipids.
The hormones produced by endocrine glands is mediated by Golgi bodies.
The complex carbohydrates (mucopolysac­charides, hyaluronic acid and hemicelluloses etc.).
So, the correct answer is 'All of the above'.


In a cell DNA is found in :-


In eukaryotic cells, most DNA is located in the cell nucleus (though some DNA is also contained in other organelles, such as in the mitochondria and the chloroplast in plants). Nuclear DNA is organized into linear molecules called chromosomes. The size and number of chromosomes varies significantly between species.


Cartilage matrix is digested during its osteogenesis through :-


Option (b) extracellular lysosomal activity is the right answer.


Which one is lysosomal activity :-

Solution: Lysosomes.know to be the suicidial bag of cells secreats many digestive explanation to bit c.removal of obstruction. now it secreats digestive refers that it has the chemical secreation which can digest things..when a cell is dead it needs to be decomposed and this is done by lysomes. It brusts out and digests out the unwanted things.. now explanation to bit b. mobilisation. These cell organelle are made by rough endoplasmic this helps in transportation of proteins and lipids to different parts of the repair worn out parts.. explanation to point a. now disintegration of tail of tadpole requires digestion of tail part cell regions.

“All cells arise from per existing cells” who said this?


Rudolf Virchow famously stated “Omnis cellula e cellula”… “All cells only arise from pre-existing cells. “The parts of the theory that did not have to do with the origin of cells, however, held up to scientific scrutiny and are widely agreed upon by the scientific community today.


Which of the following is known as “physical basis of life”?

Solution: Protoplasm is known as the physical basis of life.According to Huxley the protoplasm is the physical basis of life. Inside the cell wall of living cell the living substance is known as protoplasm. The protoplasm is a thick fluid or jelly like substance It is a very complex substance and found to be dispersed in the medium of water. Life is not possible without protoplasm hence called physical basis of life.

The term protoplasm was coined by


Purkinje coined the term protoplasm in 1839 for plant sap which is living fluid inside the cell. Initially Dujardin in 1835 observed the living juice inside the animal cell.


Find the incorrect statement


The correct option is Option C.
Animal cells are generally smaller than plant cells with their cells ranging from 10-30um in length. Animal cells shape and sizes vary greatly from irregular shapes to round shapes, most defined by the function they perform. Plant cells are larger than animal cells with the cell size ranging from 10um-100um in length.


The largest cell in the human body is


Neurons are the largest cells-

Even among those, the ones which come out of the spine and reach every part of your body.

And every part of your body is attached to your spine with a single neuron, which is also a single cell.

So from the tips of your finger runs a single neuron which goes all the way to your spine, yes, a single cell which is few feet in length.