A close analysis of Botany Chapter ‘Cell : The unit of Life‘ based on previous 22 years exam questions ( between 2000-2021) suggests that suggests that overall weightage of this chapter in the NEET Exam is 5% which means on an average 4-5 questions are asked from this chapter each year. The high priority topics of the chapter ‘Cell : The unit of Life‘ from which there is greater chance of occurrence in the NEET Exam are listed below. 1.Eukaryotic Cells 2.Overview of a Cell 3.Cell Theory 4.Introduction and Microscopy The students are advised to practice at least 200-300 questions from the high priority topics mentioned above.

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Introduction:
A close analysis of Botany Chapter ‘Cell : The unit of Life‘ based on previous 22 years exam
questions ( between 2000-2021) suggests that suggests that overall weightage of this chapter
in the NEET Exam is 5% which means on an average 4-5 questions are asked from this chapter
each year.
The high priority topics of the chapter ‘Cell : The unit of Life‘ from which there is greater chance
of occurrence in the NEET Exam are listed below.
1.Eukaryotic Cells
2.Overview of a Cell
3.Cell Theory
4.Introduction and Microscopy
The students are advised to practice at least 200-300 questions from the high priority topics
mentioned above.

2. Phone :- 0141 4005482 Exampraxis.com Email :- support@exampraxis.com
Noteworthy Points of the Chapter :
1. Cell is the fundamental structural and functional unit of all living organisms.
2. Anton Von Leeuwenhoek first saw and described a living cell and Robert Brown discovered
the nucleus.
3. Schleiden and Schwann together formulated the cell theory.
4. ‘Omnis cellula-e-cellula’ was explained by Rudolf Virchow.
5. Cells that have membrane bound nuclei are called eukaryotic whereas cells that lack a nucleus
are called prokaryotic.
6. Ribosomes are non-membrane bound cell organelles found in all cells.
7. The smallest cell is Mycoplasma of 0.3 m in length.
8. The four basic shapes of bacteria are bacillus (rod like), coccus (spherical), vibrio (comma
shaped) and spirillum (spiral).
9. A typical eukaryotic cell is of 10-20 m and the size of viruses is 0.02-0.2 m.
10. Many bacteria have small circular DNA in addition to genomic DNA and is called plasmid.
11. In bacteria, the infoldings of cell membrane is called mesosome, which is the characteristic
of prokaryotes.
12. The cell envelope of prokaryotic cell consists of three layers glycocalyx, cell wall and plasma
membrane.
13. In some prokaryotes, glycocalyx could be loose sheath called slime layer and sometimes it
may be thick and tough called capsule.
14. In bacteria, cell wall determines the shape of cell and provides structural support.
15. In cyanobacteria, the membranous extensions into cytoplasm called chromatophores
contains pigments.

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16. Motile bacteria have thin filamentous extension from their cell wall called flagella, which is
composed of three parts filament, hook and basal body in which filament is the longest
portion and extend from cell surface to the outside.
17. Surface structure present in bacteria are flagella, pili and fimbriae.
18. Ribosomes are about 15 nm by 20 nm in size and are made up of two subunits. Prokaryotes
have 70S ribosome (50S + 30S subunits) whereas eukaryotes have 80S ribosome (60S
+ 40S subunits).
19. Several ribosomes may attach to a single mRNA and form a chain called polyribosomes (or)
polysomes.
20. Reserve material in prokaryotic cells are stored in cytoplasm in the form of inclusion bodies.
21. The cell membrane is composed of lipids that are arranged in a bilayer. The membrane also
Contains protein and carbohydrates.
22. In humans, the membrane of the erythrocyte has approximately 52% proteins and 40% lipids.
23. According to fluid mosaic model , the quasi-fluid nature of lipid enables lateral movement of
proteins within the overall bilayer. This model was given by Singer and Nicolson in 1972.
24. Movement of water by diffusion across plasma membrane is called osmosis.
25. Na+
/K+
pump is an example of active transport.
26. The primary cell wall of a plant cell is capable of growth and secondary cell wall is formed
on inner (towards membrane) side of the cell.
27. The middle lamella is a layer chiefly made up of calcium pectate which glues neighbouring
cells together and plasmodesmata connect the cytoplasm of neighbouring cells.
28. The endomembrane system includes ER, golgi complex , lysosomes and vacuoles.
29. The ER, bearing ribosomes on their surface is called RER.
30. The SER is the major site of synthesis of lipids.
31. The Golgi cisternae are concentrically arranged near the nucleus with distinct convex ‘cis’ or
the forming face and concave ‘trans’ or maturing face.

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32. The vesicles from the ER fuse with cis face of golgi apparatus and move towards the
maturing/trans face.
33. Golgi apparatus is the important site of formation of glycoproteins and glycolipids.
34. The lysosomal vesicles are rich in hydrolytic enzymes that are optimally active at acidic pH.
35. The vacuole is bounded by a single membrane called tonoplast.
36. In Amoeba, the contractile vacuole is important for excretion and in protists, food vacuoles
are formed by engulfing the food particles .
37. Mitochondria and chloroplast are double membrane-bound structures.
38. The inner compartment of mitochondria is called matrix and possesses a single circular DNA
molecule.
39. The cell organelle mitochondria is the site of aerobic respiration and it divides by fission.
40. Plastids are classified, based on the pigments into chloroplasts, chromoplasts and
leucoplasts.
41. Amyloplasts, type of leucoplasts store starch (carbohydrate), elaioplasts store oils and fats
whereas aleuroplasts store proteins.
42. Chlamydomonas, a green alga has one chloroplast per cell.
43. The space limited by inner membrane of the chloroplast is called stroma .
44. Thylakoids are arranged in stacks like the piles of coins called grana and are connected to
other thylakoids of different stacks by membranous tubules called stroma lamellae.
45. The grana in the plastid is the site of light reactions and the stroma is of dark reaction.
46. The ribosomes of chloroplast and mitochondria are of 70S type.
47. Ribosomes are composed of ribonucleic acid and proteins.
48. Eukaryotic ribosomes are 80S type. Here ‘S’ is Svedberg’s unit which stands for the
sedimentation coefficient.

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49. The core of eukaryotic flagella is called axoneme which consists of nine pairs of doublets of
radially arranged peripheral microtubules and one pair of centrally located microtubules.
The arrangement of microtubules in eukaryotic flagella is referred to as 9+2 .
50. In flagella, the central tubules are connected by bridges and is enclosed by central sheath,
which is connected to one of each peripheral doublets by radial spoke.
51. The cilium and flagellum emerge from centriole-like structures called the basal bodies.
52. Centriole is made up of nine evenly spaced peripheral triplet fibrils of tubulin protein.
53. The central part of the proximal region of the centriole is called the hub, which is connected
with tubules of peripheral triplets by radial spokes.
54. The space between two parallel membranes of nuclear envelope is called perinuclear space.
55. The nuclear matrix is called nucleoplasm, which contain nucleolus and chromatin.
56. Nucleolus is a site for ribosomal RNA synthesis.
57. The interphase nucleus has a loose and indistinct network of nucleoprotein fibres called
chromatin, which contains DNA and some basic proteins called histones.
58. Based on position of centromere, chromosomes are metacentric, submetacentric,
acrocentric and telocentric.
59. The primary constriction of chromosome is called centromere. Sometimes a few
chromosomes have secondary constriction which gives the appearance of a small
fragment called the satellite.