The document provides an introduction to cells. It states that cells are the basic building blocks of living things and the human body contains trillions of cells. Cells provide structure, take in nutrients, produce energy, and perform specialized functions. Cells also contain hereditary material and can replicate themselves. Cells have various internal parts called organelles that each perform different tasks.

1. AN INTRODUCTION
TO CELL
MRS POONAM SINGH
ASSISTANT PROFESSOR
PG DEPARTMENT OF ZOOLOGY
MAGADH UNIVERSITY

2.  Cells are the basic building blocks of all living things.
 The human body is composed of trillions of cells.
 They provide structure for the body, take in nutrients from food,
convert those nutrients into energy, and carry out specialized functions.
 Cells also contain the body’s hereditary material and can make copies of
themselves.
 Cells have many parts, each with a different function.
 Some of these parts, called organelles, are specialized structures that
perform certain tasks within the cell.

4. WHAT ARE THESE?

7. STRUCTURE OF ANIMAL CELL

8. NUCLEUS SRUCTURE 2-D

9. NUCLEUS STRUCTURE 3-D

10. WHAT IS CELL CYCLE
• A cell cycle is a series of events that takes place in a cell as it grows and
divides.
• A cell spends most of its time in what is called interphase, and during this
time it grows, replicates its chromosomes, and prepares for cell division.
• The cell then leaves interphase, undergoes mitosis, and completes its
division.
• The resulting cells, known as daughter cells, each enter their own interphase
and begin a new round of the cell cycle.

12. STRUCTURE OF CHROMOSOME

14. A chromatid is a condensed DNA subunit of a chromosome.
The two chromatids of a duplicated chromosome are held together at a
region of DNA called the centromere.
Centromeres are the attachment points for microtubules, which are
responsible for the guiding the movement of chromosomes during mitosis
and meiosis.
 The nuclei of most human cells contain 46 chromosomes.
 These 46 chromosomes consist of 23 pairs of homologous chromosomes, or
homologs, meaning each of these pairs are alike, but not necessarily
identical.
 The 23rd pair of chromosomes in humans determines sex; these two
chromosomes may be very different from each other, depending on gender
(XX produces females, XY produces males).
 The convention is to describe the chromosome number in humans as 2n =
46 because the cells are diploid, meaning they have two complete sets of
chromosomes.

19. STRUCTURE OF DNA