Test: Plastids, Cilia & Flagella - NEET MCQ

The chlorophyll pigment is present in Chloroplasts.
Chlorophyll is involved in absorbing sunlight for plants. 

The centrosome is present in the cytoplasm of the animal cell. It is made up of two centrioles and helps to organize microtubules and pull chromatids apart during cell division. So, the correct answer is option C.

The Calvin cycle, Calvin–Benson–Bassham (CBB) cycle, reductive pentose phosphate cycle or C₃ cycle is a series of biochemical redox reactions that take place in the stroma of chloroplast outside the thylakoid membranes, in photosynthetic organisms. The Calvin cycle is a chemical reaction that converts carbon dioxide and other compounds into glucose. This reaction takes the products (ATP and NADPH) of light-dependent reactions and perform further chemical processes on them.

Ribosomes are the cell organelles involved in the process of protein synthesis. In a eukaryotic cell, ribosomes present in the cytoplasm synthesize proteins, which are required by the cell and the ribosomes present on rough endoplasmic reticulum, synthesize secretory proteins. Most of the enzymes are protein molecules and are synthesized on the ribosomes.

Ribophorins are transmembrane glycoproteins which are located in the membrane of the rough endoplasmic reticulum. These are absent in smooth Endoplasmic Reticulum. It helps in the attachment of larger subunit of ribosomes to endoplasmic reticulum.

Spherosomes or oleosomes are small cellular organelles enclosed by a single membrane that is responsible for the storage and synthesis of lipid. 
They are obtained from the endoplasmic reticulum, they are surrounded by a single phospholipid monolayer and are found in only plant cells.
So, the correct answer is 'Involved in photorespiration'.

MITOCHONDRIA - ii) Cristae : Mitochondrial cristae are folds of the mitochondrial inner membrane that provide an increase in the surface area. Having more cristae gives the mitochondrion more locations for ATP production to occur. In fact, without them, the mitochondrion would not be able to keep up with the cell's ATP needs. 

vi) 55-S : Mammalian mitochondrial ribosomes (55S) differ unexpectedly from bacterial (70S) and cytoplasmic ribosomes (80S), as well as other kinds of mitochondrial ribosomes.

ENDOPLASMIC RETICULUM - iv) Cytochrome P-450 : Cytochrome P450 (CYP) is a large family of well-conserved integral membrane proteins localized primarily in the membrane of the endoplasmic reticulum (ER), where these enzymes metabolize a variety of both endogenous and exogenous compounds. 

x) Detoxification: In most cells the smooth endoplasmic reticulum (abbreviated SER) is scarce.  It carries out the metabolism of carbohydrates, detoxification of natural metabolism products and of alcohol and drugs, attachment of receptors on cell membrane proteins, and steroid metabolism.

CHLOROPLAST - i) Flat membranous sacs in stroma : The flat membranous sacs in stroma of chloroplasts are called thylakoids. 

ix) Ribulose bisphosphate: Ribulose bisphosphate is a compound that plays an important role in the Calvin-Benson cycle. Layman's explanation : The process of incorporating carbon dioxide into cell carbon is called carbon fixation. Ribulose bisphosphate is found in the stroma of a chloroplast where the Calvin-Benson cycle takes place.

CENTRIOLES - iii) 9 + 0 microtubules : The centrosome is made up of 2 centrioles which are right angled to each other and is composed of a protein known as tubulin. Each centriole has 9 peripheral groups of microtubules (triplet) with no central microtubules thus, this type of arrangement in centriole is called 9+0 pattern. 

v) Membraneless structures :  Nonmembranous organelles are those cytoplasmic structures that (like membranous organelles) perform vital physiological functions for the cell but are not enclosed in membranes. These include ribosomes, centrioles, and proteasomes.

GLYOXYSOME - vii) Glucogenesis : Glyoxysomes (as all peroxisomes) contain enzymes that initiate the breakdown of fatty acids and additionally possess the enzymes to produce intermediate products for the synthesis of sugars by gluconeogenesis. 

viii) Microbody : Glyoxysomes are micro- bodies that contain isocitrate lyase and/or malate synthetase, two enzymes of the glyoxylate cycle.

Plastids are the double wall membranous organelles, which are mostly present in the plant cell. It is stores oil, starch, and proteins inside it. The plastid which stores oil is known as elaioplast. Starch storing plastids are known as amyloplast while the aleuroplast stores proteins. Potato is a rich source of starch so, it contains amyloplast as a major plastid.
So, the correct answer is option A.

• Plastids are the organelles present only in plant cell and bear color imparting pigments.
• Plastids are of three kinds, namely, leucoplasts, chromoplasts and chloroplasts.
• Chloroplast is a double membrane bound organelles with stroma which contains a stack of thyllakoids called grana.

Owing to its abundance and highest charge density among all biological ions, magnesium is most suitable for neutralizing the negative charge density of RNA nucleotide backbone. Ribosomal subunits associate to form complete ribosome in presence of Mg ion.

• Nucleus: DNA is primarily found in the nucleus of a cell, where it plays a crucial role in storing genetic information.


• Mitochondria: Mitochondria have their own DNA, known as mitochondrial DNA, which is separate from the nuclear DNA.


• Chloroplast: In plant cells, DNA is found in chloroplasts, where it is involved in photosynthesis and other cellular functions.


• Ribosome: Ribosomes are cellular organelles responsible for protein synthesis. They do not contain DNA.

Mitochondria and chloroplast are the organelles which possess their own DNA and ribosomes and considered as endosymbionts of a cell. They are originated by the endosymbiosis  fro proteobacteria and cyanobacteria respectively.

Peroxisomes contain oxidases. A major function of the peroxisome is the breakdown of very long chain fatty acids through β-oxidation. In animal cells, the very long fatty acids are converted to medium chain fatty acids, which are subsequently shuttled to mitochondria where they are eventually broken down to carbon dioxide and water.

Spherosomes also are known as plant lysosomes, single half unit membrane covered small spherical organelles which synthesize and store fats. They develop from the endoplasmic reticulum. They are spherical bodies with a diameter of about 0.5-1 mm. They contain granular contents, rich in lipids but also have some proteins. Some proteins are probably enzymatic and take part in the synthesis of fat and lipids. Thus, the correct answer is option A.

The correct option is Option C.

Each ribosome consists of 2 subunits called large and smaller subunits. The association and dissociation of subunits of ribosomes depend on Mg ion concentration. 

Mitochondria and chloroplasts can grow and divide to reproduce themselves due to the presence of its own DNA and partially depend on other cellular components. So, called as semi-autonomous organelles.

During cell division, the nuclear envelope disappears in prophase and reappears in telophase stage. 

Cytochrome P-450 is present in mitochondria and endoplasmic reticulum and absent in Golgi. It is an important protein which is involved in the metabolism.

Nucleolus is the largest structure in the nucleus of a cell. It acts as a site for synthesis of ribosomes. They also have other important functions like assembly of signal recognition particles and plays an important role in the cell's response to stress.

The centrosome is located in the cytoplasm usually close to the nucleus. It consists of two centrioles oriented at right angles or 90^o to each other embedded in a mass of amorphous material containing more than 100 different proteins. It is duplicated during S-phase of the cell cycle. Just before mitosis, the two centrosomes move apart until they are on opposite sides of the nucleus. As mitosis proceeds, microtubules grow out from each centrosome with their plus ends growing toward the metaphase plate. These clusters of microtubules are called spindle fibers.

So, the correct answer is option D.

Mitochondria and chloroplast are the semi autonomous organelles because they have their own DNA which helps them to replicate on their own. Centrioles also duplicate during the process of cell division when the DNA replicates. Ribosomes are not capable of self-duplication.
so, the correct answer is option D.

• Ribosome attached with rough E.R: Ribosomes are cellular organelles responsible for protein synthesis. The rough endoplasmic reticulum (E.R.) is a network of membranes involved in protein synthesis and sorting.


• Attachment through Glycoprotein (Ribophorin): Ribophorins are glycoproteins that help in the attachment of ribosomes to the rough endoplasmic reticulum. These glycoproteins play a crucial role in stabilizing the connection between the ribosome and the E.R.


• Function of Glycoproteins: Glycoproteins are proteins that contain carbohydrate chains attached to them. These carbohydrate chains help in cell recognition, cell signaling, and protein folding. In the case of ribosomes, glycoproteins like ribophorin assist in the attachment to the E.R.


• Importance of Attachment: The attachment of ribosomes to the rough endoplasmic reticulum is essential for the proper folding, modification, and transport of proteins. This process ensures that proteins are correctly synthesized and directed to their functional locations within the cell.

• Plasma membrane: Tubulin protein is not present in the plasma membrane.


• Cilia: Tubulin protein is present in cilia, which are hair-like structures on the surface of cells.


• Flagella: Tubulin protein is present in flagella, which are tail-like structures used for movement in some cells.


• Microtubules: Tubulin protein is a major component of microtubules, which are part of the cytoskeleton and involved in various cellular processes such as cell division and intracellular transport.

Therefore, tubulin protein is not present in the plasma membrane, while it is present in cilia, flagella, and microtubules.

Centriole is absent in nerve cells. Once nerve cells and red blood cells become specialized they leave the cell cycle and will no longer divide so there is no need for centrioles.

The axoneme of cilia and flagella typically has nine doublets of radially arranged peripheral microtubules and a pair of centrally located microtubules, forming the 9+2 array.

Spherosomes, also referred to as lipid bodies or oleosomes, are vesicles that stores triacylglycerol in the form of oil (during seed development). They are surrounded by a phospholipid monolayer - derived from ER. It is the cell organelle responsible for synthesis of cutin and wax.

• The single stranded flagella occurs in prokaryotes e.g. Bacteria etc.
• They contain only single stranded and not contain 9 + 2 system.

Factory for synthesis of sugars in autotrophic is chloroplast. Chloroplasts are organelles, specialized subunits, their main role is to conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight, and stores it in the energy storage molecules ATP and NADPH while freeing oxygen from water. They then use the ATP and NADPH to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, much amino acid synthesis, and the immune response in plants.

• Centrioles: Basal bodies of cilia and flagella are derived from centrioles, which are organelles found in animal cells. Centrioles play a crucial role in the organization of microtubules and are involved in the formation of spindle fibers during cell division.


• Structure: Centrioles consist of nine sets of triplet microtubules arranged in a cylindrical structure. These structures serve as the basis for the formation of basal bodies of cilia and flagella.


• Transformation: During the process of ciliogenesis or flagellogenesis, the centrioles migrate to the cell membrane and act as the template for the formation of basal bodies. These basal bodies then extend and give rise to microtubular structures of cilia and flagella.


• Function: Basal bodies play a crucial role in anchoring and organizing microtubules in cilia and flagella, allowing for their movement and function in cellular processes such as cell motility, sensory perception, and fluid movement.

• Aleuroplast: These are colorless plastids that store proteins and starch.


• Amyloplast: These are plastids that store starch.


• Etioplast: These are plastids that are involved in the synthesis of chlorophyll in plants that are grown in the dark.


• Elaioplast: These are plastids that store fats and oils. They are important in storing lipids in plant cells.

• Tubulin: Tubulin is the principal protein found in cilia and flagella.

• Structure: Cilia and flagella are hair-like structures found on the surface of many cells. They are composed of microtubules made up of the protein tubulin.


• Function: Tubulin plays a crucial role in the movement of cilia and flagella. It forms the structural framework that allows these organelles to bend and move in a coordinated manner, facilitating processes such as cell motility and the movement of substances across the cell surface.


• Importance: As the primary protein component of cilia and flagella, tubulin is essential for their proper function and is involved in various cellular processes that are vital for the survival and functioning of the cell.

Ribosome biogenesis is the process of making ribosomes. In prokaryotic cells, it takes place in the cytoplasm with the transcription of many ribosome gene operons. In eukaryotes, it takes place both in the cytoplasm and in the nucleolus. It involves the coordinated function of over 200 proteins in the synthesis and processing of the three prokaryotic or four eukaryotic rRNAs, as well as assembly of those rRNAs with the ribosomal proteins.