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Chapter 3 cell
1. Joel G. Soria, MD
Chapter 3
Cell Structures
and Their Functions
2. Cell
The cell is the basic
structural, functional and
biological unit of all known
living organisms.
It is the smallest unit of life that is classified as a living
thing (except virus, which consists only of DNA/RNA
covered by protein and lipids), and is often called the
building block of life
3. Functions of the Cell
1. Cell Metabolism and Energy Use
2. Synthesis of molecules
3. Communication
4. Reproduction and Inheritance
4. The cell theory states:
All organisms are composed of one or more cells
Cells are the basic unit of structure and function in
organisms.
All cells come only from other cells.
The observations of Hooke, Leeuwenhoek, Schleiden,
Schwann, Virchow, and others led to the development of the
cell theory
8. Cell Membrane
The outermost component of a cell
Extracellular / Intracellular
Selective permeable wall which determines what moves
into and out of the cell
Double phospholipid layer
9.
10. Diffusion - with the concentration gradient through the lipid
portion of the cell membrane or through membrane channels
No ATP required
Solution – Generally composed of one or more substances, called
Solutes, dissolved in a predominantly liquid or gas called Solvents.
Solutes tend to move from higher to lower area of concentration
Concentration Gradient is the difference in the concentration of a
solute in a solvent divided by the distance between the two points.
Diffusion
36. Rough Endoplasmic Reticulum
involved in some
protein production,
protein folding,
quality control and
despatch. It is called
'rough' because it is
studded with
ribosomes
37. Smooth Endoplasmic Reticulum
Smooth E R (SER) is
associated with the
production and
metabolism of fats
and steroid
hormones. It is
'smooth' because it is
not studded with
ribosomes and is
associated with
smooth slippery fats
39. Golgi apparatus
The Golgi apparatus is
integral in modifying,
sorting, and packaging
these macromolecules for
cell secretion or use
within the cell
43. • Lysosomes are
Lysosomes and Peroxisomes
•Filled with digestive enzymes
•Responsible for autolysis of injured cells
•Peroxisomes
•Carry enzymes that neutralize toxins
45. Mitochondria
Several characteristics make
mitochondria unique. The number
of mitochondria in a cell varies
widely by organism and tissue type
Mitochondria are sometimes described as "cellular power
plants" because they generate most of the cell's supply of
adenosine triphosphate (ATP)
involved in other tasks such as signaling, cellular
differentiation, cell death, as well as the control of the
cell cycle and cell growth.
52. Late Prophase
• One centriole pair of the
centrosome is moved
toward opposite pole of
spindle
centriole
Mitotic
spindle
kinetochore
• Mitotic spindle forms
• Spindle fibers attach to sister chromatids
• Nuclear envelope starts to break up
53. Metaphase
• All chromosomes are lined
up at the metaphase plate
(equator)
• Chromosomes are
maximally condensed
54. Anaphase
• Sister chromatids are pulled apart
at the centromere
• Once separated, each chromatid is
a chromosome
• Each identical chromosome moves
toward opposite poles
55. Telophase
• Chromosomes uncoil, return to
chromatin
• Two nuclear membranes form, one
around each set of new chromosomes
• Nucleoli reappear
56. Results of Mitosis
• Two daughter
nuclei
• Each with same
chromosome
number as parent
57. • Cytokinesis is the division of
the cytoplasm
• In animals, cytokinesis
occurs by cleavage
• This process pinches the
cell apart
Cleavage
furrow
Cleavage
furrow
Contracting ring of
microfilaments
Daughter cells
58. • Cancer cells have abnormal cell cycles
• They divide excessively and can form abnormal masses
called tumors
• Cancer cells ignore the control signals of normal cells -
ignore STOP signals
• Radiation and chemotherapy are effective as cancer
treatments because they interfere with cell division
Cancer:
cells growing out of control
