Singer and Nicolson (1972) proposed fluid mosaic model of plasma membrane. According to this model plasma membrane contains a lipid bilayer, which are interrupted by protein molecules. Some proteins attached at the polar surface of lipid (called, extrinsic proteins) while other partialy penetrate the lipid bilayer (called, intrinsic proteins). Intrinsic proteins are tightly binded whereas the extrinsic proteins are loosely binded to the lipid bilayer. The nature of the lipid which helps in the lateral movement of protein molecules through the membrane bilayer is called quasi fluid nature of lipid The protein can move through the membrane by the help of this characteristic of lipid Answer:(b)

Dinoflagellates are called fire algae because some forms of these protists are bioluminescent, meaning that they are living organisms that produce and emit light. They are luminescent algae; their pigment luciferin is acted upon by the enzyme luciferase causing production of light without any heat, thus the name fire algae. Option C is correct. Answer:(c)

Glycosomes: In liver cells, SER appears as tubular networks which are rich in glycogen and observed as dense particles. It contains glycogen and enzymes involved in glycogen synthesis. a = 4. The sarcoplasmic reticulum is a special type of smooth ER found in smooth and striated muscle, b=3 Baker's bodies is also called Golgi bodies, Golgi complex, Golgi some, Golgi membrane, dictyosomes, lipochondria, Dalton Complex, c= 5 Polymorphism, i.e. existence of a structure in more than one form, is an important feature of lysosomes. d= 1 Myeloid bodies are believed to be differentiated areas of smooth endoplasmic reticulum membranes, and they are found within the retinal pigment epithelium. e=2 Answer:(d)

The fluid mosaic model describes the structure of the plasma membrane as a mosaic of components —including phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character. It is sometimes referred to as a fluid mosaic because it has many types of molecules which float along the lipids due to the many types of molecules that make up the cell membrane. Thus Reason is NOT the correct explanation of Assertion Answer:(b)

In prokaryotes, nonviral extrachromosomal DNA are primarily found in plasmids whereas in eukaryotes extrachromosomal DNA are primarily found in organelles. Assertion is true and reason is false Answer:(c)

Paramural bodies are membranous or vesicular structures located between the cell walls and cell membranes of plant and fungal cells. When these are continuous with the cell wall, they are termed lomasomes Answer:(b)

A kinetochore is a disc-shaped protein structure associated with duplicated chromatids in eukaryotic cells where the spindle fibers attach during cell division to pull sister chromatids apart Answer:(a)

Answer:(b)

The membrane contains membrane proteins, including integral proteins that go across the membrane serving as membrane transporters Answer:(a)

Answer:(d)

The plasma membrane is composed of a phospholipid bilayer, which is two layers of phospholipids back-to-back. Phospholipids are lipids with a phosphate group attached to them. The phospholipids have one head and two tails. The head is polar and hydrophilic Answer:(b)

typical eukaryotic cell. (10 -20μm) typical bacteria. (1- 2 μm) PPLO ( about 0.1 μm) Viruses ( 0.02 – 0.2 μm) Answer:(a)

Endomembrane system does not include mitochondria, chloroplasts, or peroxisomes they are semi - autonomous organelle and have functions other than vesicular transport. Therefore, these are not part of endomembrane system. Answer:(b)

Each stack of cisternae forms a dictyosome which may contain 5 to 6 Golgi cisternae in animal cells or 20 or more cisternae in plant cells. Answer:(a)

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

Answer:(a)

Dictyosome organelle is found in plant cells and functionally equivalent to the Golgi apparatus of animal cells. Glyoxysomes are specialized peroxisomes found in plants. Answer:(a)

Polymorphic cell organelle is lysosome because of its different forms and functions. Peroxisomes are small, membrane-enclosed organelles. The structure of the Golgi Complex is pleomorphic Answer:(b)

In cilia and flagella, the microtubules are organized as a circle of nine double microtubules on the outside and two microtubules in the center. Answer:(a)

Chloroplasts work to convert light energy of the Sun into sugars that can be used by cells. Mitochondria, using oxygen available within the cell convert chemical energy from food in the cell to energy Answer:(b)

Telocentric Chromosomes. Telocentric chromosomes are not seen in healthy humans, since they are unstable and arise by misdivision or breakage near the centromere and are usually eliminated within a few cell divisions. Answer:(d)

Answer:(a)

Centriole is organized like a wheel containing nine triplets at about 40° angle arranged in peripheral region Answer:(a)

Answer:(a)

Answer:(a)

Answer:(b)

A Gram positive organism lacks an outer (LPS) membrane but has a thick layer of peptidoglycan and no LPS outer membrane. This facilitates access of cell-wall active antibiotics (eg. penicillin/betalactam or vancomycin-type antibiotics) to their site of action (the peptidoglycan). Statement ‘c’ is incorrect statement Porin are present in the outer membrane of gram-negative bacteria and some gram-positive mycobacteria (mycolic acid-containing actinomycetes), the outer membrane of mitochondria, and the outer chloroplast membrane. Statement ‘a’ is correct statement Chemically, 60 to 90% of the Gram-positive cell wall is peptidoglycan or murein is a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria. Statement ‘b’ is correct statement In Gram-negative bacteria there are two pairs of rings i.e. four rings are L-(lipopolysaccharide) ring, P-(peptidoglycan) ring, S-(super membrane) ring, and M-(membrane) ring. Outer membrane in Gram negative bacteria is made up of Lipopolysacchride (LPS). It is this layer which contributes to the pathogenicity in Gram negative bacteria which is absent in Gram positive bacteria.Gram-positive bacteria have a single pair of rings. The S-ring is attached to inside thick layer of peptidoglycan and M-ring is attached to cell membrane Answer:(c)

Cell dies if lysosomes get ruptured in a cell Answer:(a)

Thylakoid - Flattened membranous sacs forming the grana of chloroplasts. Option c is correctly matched. Centrioles are involved in the formation of the spindle apparatus, which functions during cell division. RNA Synthesis takes place within the nucleus of eukaryotic cells. Option a is not correct match. Lysosomes enzymes are active in acidic conditions, requiring the organelle to maintain an optimal luminal pH between 4 and 5. Option b is not correct match. Ribosomes in chloroplast are 70 s type while those of cytoplasm in eukaryotic cells are 80 S type. The enzymes of lysosome (called suicidal bag) function at acidic pH (i.e., 5). Option d is not correct match. Answer:(c)

Answer:(c)

Anthocyanins are water-soluble vacuolar pigments that, depending on their pH, may appear red, purple, blue or black. Answer:(d)

Answer:(b)

Meristematic cells are packed closely together without intercellular spaces. The cell wall is a very thin primary cell wall. Answer:(b)

Steroid hormones are derivatives of cholesterol that are synthesized by a variety of tissues, most prominently the adrenal gland and gonads. Answer:(d)

Answer:(b)

The major component of the bacterial cell wall is peptidoglycan or murein. a = 4 Hopanoids have been found in membranes of bacteria, lichens, bryophytes, ferns and fungi. b = 3 Cells were found to contain metachromatic granules (also called volutin granules) consisting of inclusion bodies of inorganic polyphosphates, c = 2 a fimbria also referred to as an "attachment pilus" d =1 Answer:(d)

The secondary walls of woody tissue and grasses are composed predominantly of cellulose, lignin, and hemicellulose (xylan, glucuronoxylan, arabinoxylan, or glucomannan) Statement (i) correct Statement (iv) false. Meristematic cells are packed closely together without intercellular spaces. The cell wall is a very thin primary cell wall. Statement (ii) correct. Primary and secondary walls contain cellulose, hemicellulose and pectin. Statement (iii) correct Answer:(a)

Answer:(d)

Centrioles are cylindrical structures that composed of groupings of microtubules arranged in 9+3 pattern. Statement “i” false. The centrosome is the main microtubule organizing center in animal cells. It consists of a pair of centrioles (an older mother centriole and a newer daughter centriole) surrounded by amorphous pericentriolar material. Statement “ii” is true Each centriole has an organization like the cartwheel. They are made of nine evenly spaced peripheral fibrils of tubulin. Each of the peripheral fibril is a triplet. The adjacent triplets are also linked to each others. Statement “iii” is false Centrioles form the basal bodies of cilia and flagella and spindle fibres. The centrioles give rise to spindle apparatus during cell division in animal cells.. Statement “iv” true Answer:(a)

Answer:(d)

Answer:(b)

Answer:(b)

Answer:(d)

Answer:(a)

Answer:(a)

Answer:(c)

Answer:(b)

Answer:(c)

Answer:(a)

Answer:(a)