7. Over a century later, many debates about cells
began amongst scientists. Most of these
debates involved the nature of cellular
regeneration, and the idea of cells as a
fundamental unit of life. Cell theory was
eventually formulated in 1838. This is usually
credited to Matthias Schleiden and Theodor
Schwann. However, many other scientists
like Rudolf Virchow contributed to the theory.
Cell theory has become the foundation of
biology and is the most widely accepted
explanation of the function of cells.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23. The protoplasmic mass of the cell inner to plasma membrane and
excluding nucleus is called the
It comprises cytosol (the gel-like substance enclosed within the
cell membrane) – and the organelles – the cell's internal sub-
structures. All of the contents of the cells of prokaryote
organisms (such as bacteria, which lack a cell nucleus) are
contained within the cytoplasm. Within the cells of eukaryote
organisms the contents of the cell nucleus are separated from
the cytoplasm, and are then called the nucleoplasm.
24.
25.
26.
27.
28.
29.
30. The is a type of organelle in
the cells of eukaryotic organisms that forms an interconnected network of
flattened, membrane-enclosed sacs or tubes known as Cisternae. The
endoplasm is the inner core of the cytoplasm and the membranes of the ER
are continuous with the outer membrane of the nuclear envelope. ER is
present in all the cells except prokaryotes and mammalian erythrocytes.
They are of two types:-
# Rough Endoplasmic Reticulum-
It is characterized by the presence of
ribosomes on its surface. It synthesizes
lipids. It is formed of vescicles and tubules.
# Smooth Endoplasmic Reticulum-
It is devoid of ribosomes on its surface.
It synthesizes proteins. It is mainly
formed of flat sacs or cisternae.
31.
32. The GOLGI APPARATUS , also known as
the GOLGI COMPLEX, is an organelle found in
most eukaryotic cells. It was identified in 1897
by the Italian physician Camillo Golgi and
named after him in 1898.
Golgi apparatus packages proteins into
membrane-bound vesicles inside the cell before
the vesicles are sent to their destination. It
resides at the intersection of the secretory,
lysosomal, and endocytic pathways. It is of
particular importance in
processing proteins for secretion, containing a
set of glycosylation enzymes that attach
various sugar monomers to proteins as the
proteins move through the apparatus.
It is a single unit in animal cell, whereas it is
made of two separate units, called dictyosomes,
in the plant cell.
33.
34.
35.
36.
37. A LYSOSOME is a membrane-
bound cell organelle found in most
animal cells (they are absent in red
blood cells). Structurally and
chemically, they are spherical vesicles
containing hydrolytic enzymes for
intracellular digestion and waste
disposal. They are also known as
“Suicide or Digestive Bags”. Old
organelles, germs, food particle, etc.
fuse with lysosomes for disposal by
digestion. In damaged cell, lysosomes
burst to release enzymes for digestion
of cellular components. They are found
in animal cells except mammalian
RBC’S.
38.
39. The PLASTID is a major double-
membrane organelle found, among
others, in the cells of
plants and algae. Plastids are the
site of manufacture and storage of
important chemical compounds used
by the cell. They often contain
pigments used in photosynthesis,
and the types of pigments present
can change or determine the cell's
color. They have a common origin
and possess a double-stranded DNA
molecule that is circular, like that
of prokaryotes.).
