Test: Cell: The Unit of Life - 1 - NEET MCQ

The shapes of bacteria are bacillus (rod like), coccus (spherical), vibrio (comma shaped) and spirillum (spiral).

Line in NCERT: "The four basic shapes of bacteria are bacillus (rod like), coccus (spherical), vibrio (comma shaped) and spirillum (spiral)."

The cytoskeleton in a cell is involved in functions like mechanical support, motility, maintenance of the shape of the cell.

Line in NCERT: "The cytoskeleton in a cell are involved in many functions such as mechanical support, motility, maintenance of the shape of the cell."

Evaluating each statement for accuracy:

Statement A: This is correct. The lipid component of the plasma membrane does primarily consist of phosphoglycerides.
Statement B: This is incorrect. Polar molecules generally cannot pass through the lipid bilayer easily due to their polarity and typically require carrier proteins or channels to facilitate their transport.
Statement C: This is incorrect. The secondary cell wall is rigid and provides structural integrity; it does not grow once laid down and is formed on the inner side of the primary cell wall.
Statement D: This is correct. The quasi-fluid nature of lipids in the plasma membrane does allow for the lateral movement of proteins within the membrane.
Statement E: This is correct. The middle lamella, rich in pectins, acts like a glue that holds neighboring plant cells together.
Thus, two statements (B and C) are incorrect. Hence, the correct answer is Option D: Two.

Line in NCERT: "As the polar molecules cannot pass through the nonpolar lipid bilayer, they require a carrier protein of the membrane to facilitate their transport across the membrane."

Anton Von Leeuwenhoek first saw and described a live cell.

Line in NCERT: "Anton Von Leeuwenhoek first saw and described a live cell."

Ribosomes are granules formed of rRNA and protein. Ribosome provide space for protein synthesis during translation.

Line in NCERT: "Ribosomes are composed of ribonucleic acid (RNA) and proteins and are not surrounded by any membrane."

Mitochondria contain cristae, finger like projection of inner layer, thylakoid is present in chloroplast and lysosome is a digestive enzyme but RNA is absent in Chromosome.

Leucoplasts are involved in storing oils and fats, carbohydrates (starch), and proteins in plant cells. They can differentiate into various types depending on what they store: amyloplasts (storing starch), elaioplasts (storing oils), and proteinoplasts (storing proteins).

Line in NCERT: "The leucoplasts are the colourless plastids of varied shapes and sizes with stored nutrients: Amyloplasts store carbohydrates (starch), e.g., potato; elaioplasts store oils and fats whereas the aleuroplasts store proteins."

Mitochondria are the sites of aerobic respiration. They producecellular energy in the form of ATP

Line in NCERT: "Mitochondria are the sites of aerobic respiration. They produce cellular energy in the form of ATP, hence they are called 'power houses' of the cell."

In plant cells, the chloroplasts are responsible for trapping light energy essential for photosynthesis. The grana, in the plastid, is the site of light reactions.

Line in NCERT: "The grana, in the plastid, is the site of light reactions and the stroma of dark reactions."

Lysosomes are single membrane structures containing enzymes for digestion of all types of macromolecules.

The cytoskeleton of a cell is made up of microtubules, actin filaments,and intermediate filaments. These structures give the cell its shape and help organize the cell’s parts. They also provide a basis for movement and cell division

Line in NCERT: "The cytoskeleton is made of microtubules, microfilaments and intermediate filaments present in the cytoplasm."

Golgi apparatus is the important site of formation of glycoproteins and glycolipids.

Line in NCERT: "Golgi apparatus is the important site of formation of glycoproteins and glycolipids."

Mitochondria are present in both plant as well as animal cells. Plastids and central vacuoles are present in plant cells and centrioles are present in only animal cells.

Line in NCERT: "Mitochondria divide by fission."

Cilia present in prokaryotic organisms consist of microtubules. These microtubules are arranged in 9+2 order in which 2 forms the center and 9 are arranged at periphery.

Line in NCERT: "The axoneme usually has nine doublets of radially arranged peripheral microtubules, and a pair of centrally located microtubules. Such an arrangement of axonemal microtubules is referred to as the 9+2 array."

(A) is incorrect because only the ER, particularly the smooth ER, is known for synthesizing lipids and steroidal hormones, while the Golgi apparatus is involved in their modification and transport
 (B) is correct as both the ER and Golgi apparatus are structured from cisternae, tubules, and vesicles.

 (C) is also correct as both are integral components of the cell's endomembrane system, facilitating various cellular processing and transport tasks.

( D) is incorrect as the primary involvement in the formation of the plasma membrane during cytokinesis is attributed to the Golgi apparatus through its vesicles, whereas the ER's role is indirect, through the provision of necessary lipids.

Thus, the correct answer is Option B: Only (B) and (C), as these are the features common to both the ER and the Golgi apparatus.

Line in NCERT: "While each of the membranous organelles is distinct in terms of its structure and function, many of these are considered together as an endomembrane system because their functions are coordinated. The endomembrane system include endoplasmic reticulum (ER), golgi complex, lysosomes and vacuoles."

The diagram provided appears to be of a mitochondrion, based on the structure shown including cristae and membranes. Here's the evaluation of each statement according to typical mitochondrial anatomy and function:

1. 'C' possesses DNA molecule, RNA molecule and 80 S ribosomes: This statement is incorrect because mitochondria contain their own DNA and RNA, but the ribosomes are 70S, not 80S, which are typical of eukaryotic cytoplasm.

2. 'A' and 'B' have their own specific enzymes: This statement is likely correct as these areas, presumably representing the inner membrane (A) and the matrix (B) of the mitochondrion, indeed contain specific enzymes critical for mitochondrial functions such as the electron transport chain in the inner membrane and the enzymes for the Krebs cycle in the matrix.

3. 'E' made by inner membrane towards the intermembrane space: This statement seems incorrect. If 'E' is labeling a part of the structure extending from the inner membrane, it is likely a cristae, which is an infolding of the inner membrane into the matrix, not towards the intermembrane space.

4. 'B' forms the continuous limiting boundary of the organelle: This statement is incorrect as 'B' likely represents the matrix or perhaps part of the inner membrane structures; it does not form the continuous outer boundary of the mitochondrion. The outer membrane would be the continuous boundary.

Given these evaluations, the correct answer is:

2. 'A' and 'B' have their own specific enzymes

A cell membrane shows fluid behavior due to mosaic of lipid and proteins. Fluid mosaic model of plasma membrane is most accepted and recent model.

Line in NCERT: "According to this, the quasi-fluid nature of lipid enables lateral movement of proteins within the overall bilayer."

The staining procedure developed by Gram viz., those that take up the gram stain are gram positiveand the others that do not are called gram negative bacteria.

Line in NCERT: "by Gram viz., those that take up the gram stain are Gram positive and the others that do not are called Gram negative bacteria."

• A. Thylakoids are described as flat membranous sacs, but specifically, they are located within the chloroplasts, not the Golgi apparatus. The correct match here would be (iii) Flat membranous sacs in stroma, which more accurately describes the location of thylakoids in the chloroplast stroma.

• B. Cristae are the infoldings in mitochondria, where the mitochondrial membrane is folded inward to increase the surface area. Therefore, the correct match is (iv) Infolding in mitochondria.

• C. Cisternae are flat membranous sacs found in the Golgi apparatus. Thus, the correct description is (i) Disc-shaped sacs in Golgi apparatus.

• D. Chromatin refers to the material of which chromosomes are composed, including DNA and proteins. It represents the condensed structure of DNA, so it matches with (ii) Condensed structure of DNA.

• A with iii
• B with iv
• C with i
• D with ii

The correct sequence for the pathway of a secretory product typically follows these steps:

Synthesis in the Rough Endoplasmic Reticulum (RER) - Proteins are synthesized and undergo initial modifications.
Transport via Vesicles - Proteins are packed into vesicles that bud off from the RER.
Cis Face of the Golgi Apparatus (GB) - Vesicles fuse with the cis face of the Golgi body, where further modification of proteins occurs.
Transit Through Golgi Apparatus - Proteins move from the cis to the trans region of the Golgi, undergoing further modifications.
Vesicles to Plasma Membrane - Finished proteins are packaged into vesicles that bud off from the trans face of the Golgi and are transported to the plasma membrane.
Therefore, Option A accurately describes the typical secretory pathway, starting from the Endoplasmic Reticulum (ER), moving through the Golgi body from the cis to the trans region, and finally to the plasma membrane.

Line in NCERT: "Materials to be packaged in the form of vesicles from the ER fuse with the cis face of the golgi apparatus and move towards the maturing face."

The correct order from smallest to largest is virus, PPLO (Mycoplasma), typical bacteria, and typical eukaryotic cell. Viruses are the smallest, usually only visible with an electron microscope. PPLOs are slightly larger than the largest viruses but smaller than typical bacteria. Typical bacteria are larger than viruses and PPLOs and are visible under light microscopes. Eukaryotic cells are the largest, significantly bigger than viruses, PPLOs, and typical bacteria, making Option A the correct choice.

Line in NCERT: "Typical bacteria (1-2 µm) PPLO (about 0.1 µm) A typical eukaryotic cell (10-20 µm) Viruses (0.02-0.2 µm)"

Rudolf Virchow(1855) first explained that cells divided and new cells are formed .

Line in NCERT: "Rudolf Virchow (1855) first explained that cells divided and new cells are formed from pre-existing cells (Omnis cellula-e cellula)."

The leucoplasts are the colourless plastids of varied shapes and sizes with stored nutrients. Leucoplast includes: a) Amyloplasts storing carbohydrates. b) Elaioplastsstoring oils and fats and c) Aleuroplasts storing proteins.

Line in NCERT: "the leucoplasts are the colourless plastids of varied shapes and sizes with stored nutrients: Amyloplasts store carbohydrates (starch), e.g., potato; elaioplasts store oils and fats"

Mitochondria are double membranous structure. The inner membrane of mitochondria thrown into folds to form finger-like structureis called cristae.

Line in NCERT: "The inner membrane forms a number of infoldings called the cristae (sing.: crista) towards the matrix."

Reserve material in prokaryotic cells are stored in the cytoplasm in the form of inclusion bodies.

Line in NCERT: "Inclusion bodies: Reserve material in prokaryotic cells are stored in the cytoplasm in the form of inclusion bodies."