CELL PHYSIOLOGY.ppt.....................

very helpful

1. Cell Physiology

2. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
An Introduction to Cells
Cell Theory
Developed from Robert Hooke’s research
Cells are the building blocks of all plants and
animals
All cells come from the division of preexisting cells
Cells are the smallest units that perform all vital
physiological functions
Each cell maintains homeostasis at the cellular
level

3. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
An Introduction to Cells
Somatic cells (soma = body)
All body cells except sex cells
Sex cells (germ cells)
Reproductive cells
Male sperm
Female oocyte (a cell that develops into an egg)

4. CELL
The study of cells is called Cytology
Cells vary greatly in SIZE and
STRUCTURE: ( 5 um - 10 nm)
Cells have two main parts - NUCLEUS &
CYTOPLASM

5. Cell differentiation
Mechanism: differential gene
activation allows creation of
specialized cells
From 1 zygote to 200 different types of cells

6. Definition
Cells are the basic unit of life within the human body
Approximately 100 trillion cells make up the typical
human, each specially adapted to perform one or a
few particular functions
25 trillion red blood cells act to transport oxygen from
the lungs to all tissues in the body
All cells have some basic commonalities
Oxygen reacts with carbohydrates, fat, and protein to
release energy
Nutrient consumption and energy production
mechanisms are similar
Nearly all cells have the ability to reproduce
additional, similar cells

7. Basic Cell Functions
Sensing and responding to changes in surrounding
environment
Control exchange of materials between cell and its
surrounding environment
Obtain nutrients and oxygen from surrounding environment
Eliminate carbon dioxide and other wastes to surrounding
environment
Perform chemical reactions that provide energy for the
cell
Synthesize needed cellular components

8. Cell Functions
Metabolism
–Use molecules for cellular functions, to make ATP and heat
Molecule synthesis
–Different cells synthesize different molecules. Structural
and functional characteristics are based on molecules they
produce.
Communication
–Cells produce and respond to chemical and electrical
signals
Reproduction and inheritance
–Most cells have a complete copy of all of our genetic
information. This is passed down from cell to cell and from
parent to child

9. An Introduction to Cells
A cell is surrounded by a watery medium known as
the extracellular fluid
Extracellular fluid is interstitial fluid + plasma +
cerebrospinal fluid + synovial fluid
The plasma membrane separates cytoplasm
(intracellular fluid) from the extracellular fluid (ECF)
Cytoplasm= cytosol + organelles
Cytosol = liquid
Organelles are intracellular structures

11. **Components are indicated by blue color

12. Parts of the cell
Cell membrane
Cytoplasm
Nucleus and nucleolus
Organelles- smooth and rough
endoplasmic reticulum, mitochondria,
lysosomes, golgi Apparatus, peroxisomes,
Centrosomes, cilia, flagella,
Microfilaments, microtubules etc

13. Cytoplasm
Cytosol (watery matrix)
Dissolved materials:
–nutrients, ions, proteins, and waste products
High potassium/low sodium levels compared to ECF
High protein content compared to ECF
High carbohydrate/low amino acid and fat inside cell
Fluids
Organelles=“little organs”
Structures with specific functions
Inclusions
stored nutrients (e.g., glycogen) in plasma membrane

15. Cell/Plasma membrane
Protective sheath of cell body
Phospholipid bilayer made of hydrophobic
and hydrophilic parts
https://www.online-sciences.com/biology/
histolgy-molecular-structure-of-the-cell-
membrane-cell-function-structure/

16. Cell/Plasma membrane

17. Cell membrane cont.
Components of cell membrane
Proteins -55%
Lipids-25%
Cholesterol-13%
Other lipids-4%
Carbohydrates-3%

18. Functions of the cell membrane
•Selective Permeability: The cell membrane regulates the
entry and exit of substances, allowing nutrients, gases, and
water in while keeping harmful substances out. It maintains
homeostasis by being selectively permeable.
•Protection: It serves as a barrier, protecting the cell’s internal
components from the external environment, maintaining the
integrity of the cell.
•Communication: The cell membrane contains receptor
proteins that allow the cell to receive and respond to signals
from its environment, such as hormones, neurotransmitters, or
other chemical signals.

19. Functions of the cell membrane
•Cell Recognition: Glycoproteins and glycolipids on the
membrane help in cell recognition, allowing cells to identify
each other and communicate for immune responses or tissue
formation.
•Transport: It facilitates the transport of materials through
passive (diffusion, osmosis) and active (endocytosis,
exocytosis, active transport) mechanisms.
•Structural Support: The membrane provides structural
support by anchoring the cytoskeleton, which helps maintain
the shape of the cell.
•Cell Adhesion: It plays a role in cell-to-cell adhesion, enabling
the formation of tissues and communication between cells in
multicellular organisms.

20. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Functions (Summary)
Functions of the Plasma Membrane
Physical isolation
Barrier
Regulates exchange with environment
Ions and nutrients enter
Wastes eliminated and cellular products released
Monitors the environment
Extracellular fluid composition
Chemical signals
Structural support
Anchors cells and tissues

21. More about Plasma Membrane
Comprised of a phospholipid bilayer-double layer of
phospholipid molecules
Hydrophilic heads—toward watery environment, both sides
Hydrophobic fatty-acid tails—inside membrane, some are
kinked to enhance fluidity of membrane.
Cholesterol (amphipathic) stabilizes membrane.
It is selectively permeable (semi-permeable). It is a barrier
to large molecules, ions and water soluble compounds.

22. Plasma Membrane

23. Plasma Membrane
Fluid Mosaic Model-describes the plasma
membrane as fluid, not static.
Movement of plasma membrane due to:
Unsaturated hydrophobic fatty acid tails-kink
The fluid mosaic model describes the membrane as a
dynamic and flexible structure composed of a fluid lipid
bilayer with various proteins embedded in or attached to
it. Watch this video
https://www.youtube.com/watch?v=ipa1vmQ7H_4

24. Membrane Fluidity Demonstrated:

25. Membrane Fluidity

26. Plasma Membrane
Membrane Proteins
Integral proteins
Span the membrane
They are amphipathic-polar and nonpolar
Peripheral proteins
Bound to inner or outer surface of the membrane

27. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Plasma Membrane
Figure 3–2 The Plasma Membrane.

28. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Plasma Membrane
Several Types of Membrane Proteins
Anchoring proteins (stabilizers)
Attach to inside or outside structures
Recognition proteins (identifiers)
Label cells as normal or abnormal
Enzymes
Catalyze reactions
Receptor proteins
Bind and respond to ligands (ions, hormones)
Carrier proteins
Transport specific solutes through membrane
Channels
Regulate water flow and solutes through membrane

29. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Plasma Membrane
Figure 3–2 The Plasma Membrane.

30. Plasma Membrane
Membrane Carbohydrates
Proteoglycans, glycoproteins, and glycolipids
Extend outside cell membrane
Form sticky protection “sugar coat” (glycocalyx)
Functions of the glycocalyx
Lubrication and protection
Anchoring and locomotion
Specificity in binding (receptors)
Recognition (immune response & tissue growth)

31. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Plasma Membrane
Figure 3–2 The Plasma Membrane.

32. II. Organelles
Nonmembranous organelles
No membrane
Direct contact with cytosol
Includes the cytoskeleton, microvilli, centrioles, cilia,
ribosomes, and proteasomes
 Membranous organelles
Covered with plasma membrane
Isolated from cytosol
Includes the nucleus, endoplasmic reticulum (ER), the
Golgi apparatus, lysosomes, peroxisomes, and
mitochondria

33. The Cytoskeleton
The Cytoskeleton — structural proteins for
shape and strength
Microfilaments
Intermediate filaments
Microtubules

34. Figure 3.16Figure 3.16

35. Microfilaments
Microfilaments—thin filaments composed of
the protein actin
Provide additional mechanical strength
Interact with proteins for consistency
Pair with thick filaments of myosin for muscle
movement

36. Intermediate filaments
Intermediate filaments—mid-sized between
microfilaments and thick filaments
Durable (collagen)
Strengthen cell and maintain shape
Stabilize organelles
Stabilize cell position

37. Microtubules
Microtubules—large, hollow tubes of tubulin
protein
Strengthen cell and anchor organelles
Change cell shape
Move vesicles within cell (kinesin and dynein)
During cellular division they form the spindle
apparatus that attaches to chromosomes to pull
them to opposite ends of the dividing cell

38. Cytoskeleton

39. Centrioles and centrosomes
https://
biologydic
tionary.ne
t/wp-
content/
uploads/
2017/09/
OSC-
Microbio-
03-04-
Centroso
me.jpg

40. Centrioles
Two Short cylinders only visible during cell division
Formed by à ring of nine microtubule triplets
Two pairs in cells that undergo mitosis
Not présent in cells/egg that undergo meiosis
Usually lié next to each other at right angles
Housed in the centromere
Barrel-shaped, composed of nine microtubule
triplets
Forms spindle apparatus during cellular division and
used in cilia and sperm flagella for movement

41. Major microtubule organizing centre of
most cells
Site at which New microtubules are
formed
Centrosomes

42. Cellular Extensions
Microvilli
Extension of the cell to increase surface area of the cell
Found in brush border of small intestine, stereocilia of ear,
WBC, and oocyte.
Cilia
Small, whip-like, motile extensions of the cell surface
Ciliary movement move fluids across the cell surface
Found in bronchioles and fallopian tubes
Flagella
Tail of sperm that consists of microtubules

43. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Microvilli
Figure 3–3 The Cytoskeleton.

44. Cilia

45. Ribosomes
Ribosomes
Composed of two subunits containing protein + RNA
Made in nucleus and shipped to cytoplasm
Build polypeptides in protein synthesis
Two types
Free ribosomes in cytoplasm:
–manufacture proteins for cell
Fixed ribosomes attached to ER:
–manufacture proteins for cell membrane, lysosomes, or secretion

46. Figure 3.12Figure 3.12

47. Largest Organelle
Nucleus (stained yellow)

48. Nucleus
Houses the DNA
Serves as the cell’s control center
Surrounded by two membranes, together called
the nuclear envelope
The nuclear envelope is studded with nuclear pores.
Nuclear pores regulate traffic into and out of the
nucleus.
Nucleus

49. Inside the nucleus:
Chromatin – composed of DNA + proteins
Nucleolus – site of ribosome manufacture
Nucleoplasm – fluid inside the nucleus
Figure 3.9Figure 3.9
Nucleus

50. Nucleus
Nuclear Envelope: A double membrane that
surrounds the nucleus, separating it from the
cytoplasm. It contains nuclear pores that regulate
the movement of molecules in and out of the
nucleus.
Nucleoplasm: The semi-fluid substance inside
the nucleus, also known as nuclear sap, which
provides a medium for the diffusion of molecules.

51. Chromatin: DNA molecules wrapped around proteins
(histones). Chromatin exists in two forms:
Euchromatin: Loosely packed chromatin, accessible
for transcription (active gene expression).
Heterochromatin: Densely packed chromatin,
transcriptionally inactive.
Nucleolus: A dense region within the nucleus
responsible for producing and assembling ribosomal
RNA (rRNA) and ribosome subunits.
Nuclear Matrix: A network of fibers within the nucleus
that provides structural support and organizes the
chromatin.
Nuclear Pores: Large complexes that regulate the
exchange of materials (such as RNA and proteins)
between the nucleus and cytoplasm.

52. Functions of the nucleus
Genetic Information Storage: The nucleus houses
the cell’s DNA, which contains the genetic instructions
needed for the development, functioning, and
reproduction of the organism.
Gene Expression Regulation: The nucleus controls
the transcription of DNA into messenger RNA (mRNA),
which determines which proteins are made, thereby
regulating cellular functions.
Ribosome Production: Within the nucleolus (a
structure inside the nucleus), ribosomal RNA (rRNA) is
synthesized and combined with proteins to form the
subunits of ribosomes, which are essential for protein
synthesis

53. Functions of the nucleus
DNA Replication: The nucleus oversees the replication of
DNA during the cell cycle, ensuring that each daughter cell
receives an exact copy of the genetic material during cell
division (mitosis or meiosis).
Cell Growth and Reproduction: By controlling gene
expression and DNA replication, the nucleus regulates cell
growth and the reproduction of cells.
Chromatin Organization: The nucleus is responsible for
packaging DNA into chromatin, organizing it into
chromosomes during cell division, and maintaining its
structural integrity.
RNA Processing: Precursor mRNA (pre-mRNA) is
processed within the nucleus to form mature mRNA, which is
then transported out of the nucleus for protein synthesis in
the cytoplasm.

54. Endoplasmic reticulum
Endoplasmic reticulum (ER)
Continuous with outer nuclear envelope
Has cisternae are storage chambers within
membranes
Functions
Synthesis of proteins, carbohydrates, cholesterol and lipids
Storage of synthesized molecules and materials
Transport of materials within the ER, to Golgi Apparatus, and
extracellularly
Detoxification of drugs or toxins

55. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Endoplasmic reticulum
Figure 3–5 The Endoplasmic Reticulum.

56. Smooth endoplasmic reticulum (SER)
Smooth endoplasmic reticulum (SER)
No ribosomes attached
Synthesizes lipids and carbohydrates:
–phospholipids and cholesterol (membranes)
–steroid hormones (reproductive system)
–glycerides (storage in liver and fat cells)
Metabolizes lipids ad breaks down glycogenglucose
Absorbs, synthesizes and transports lipids
Detoxifies drugs, pesticides and carcinogens (liver/ kidney)
Modified SER in skeletal muscle and cardiac muscle for
storage of Ca
+2

57. Rough endoplasmic reticulum (RER)
Rough endoplasmic reticulum (RER)
Surface covered with ribosomes:
–active in protein and glycoprotein synthesis
–folds polypeptides protein structures
–encloses products in vesicles that go to Golgi apparatus

58. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Rough endoplasmic reticulum (RER)
Figure 3–5 Rough Endoplasmic Reticulum.

59. Basis Smooth ER Rough ER
Ribosomes
In the case of Smooth
ERs, the ribosomes are
absent
In the case of Rough
ERs, the ribosomes are
present
Location
The location of the
Smooth ER is basically
near the cell membrane
The location of the
Rough ER is mainly
near the cytoplasm
Origin
The origin of Smooth ER
occurs by the process of
ribosome shedding
The origin of Rough ER
occurs from the nuclear
membranes
Key Differences Between Smooth ER and Rough ER

60. Key Differences Between Smooth ER and Rough ER
Composition
The main components of
Smooth ER are tubules
The main component of
Rough ER is cisternae
Function
The Major function of
Smooth ER is lipids
synthesis and storing of
proteins and lipids
The major function of
Rough ER is the
synthesis and storage of
proteins
Localization
The main form of
Smooth ER is in lipid
form cells like glycogen
storing cells in the liver,
adipocytes, interstitial
cells of the testis,
muscle cells, adrenal
cortex cells, leukocytes,
etc.
The main form of Rough
ER is the protein-
forming cells like the
goblet cells, pancreatic

61. Golgi Apparatus
A stack of membranous sacs
Vesicles pinch off from the ER to fuse with the
Golgi apparatus and empty their digestive enzyme,
protein or lipid contents.
The lipids and proteins are then modified, sorted,
and sent to their appropriate destination in new
vesicles that bud off from the Golgi apparatus.
The digestive enzyme contents remain in the cell
as lysosomes
Golgi Apparatus

62. Golgi Apparatus
© 2016 Pearson Education, Inc.
Cisterns
New vesicles
forming
Transport
vesicle
from
trans face
Cis
­­face—­
“receiving” side of
Golgi apparatus
Transport vesicle
from rough ER
Trans face—
“shipping” side of
Golgi apparatus
Newly secreted
proteins
Secretory vesicle
New vesicles forming
Golgi
apparatus
Transport vesicle at
the trans face
Electron micrograph of the Golgi
apparatus (90,000)
Many vesicles in the process of pinching off
from the Golgi apparatus

63. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Golgi Apparatus
Figure 3–7 Functions of the Golgi Apparatus.

64. Lysosomes
Lysosomes=powerful, acidic, enzyme containing
vesicles
Clean up inside cells
Break down large molecules
Digest ingested bacteria, viruses and toxins
Recycle damaged organelles
Eject wastes by exocytosis
Autolysis
Auto- = self, lysis = break
Self-destruction of damaged cells:
–lysosome membranes break down
–digestive enzymes released
–cell decomposes
–cellular materials recycle

65. Figure 3.11Figure 3.11

66. Peroxisomes
Peroxisomes
Enzyme containing vesicles (oxidases + catalases)
Oxidases use O
2 to detoxify harmful substances and
neutralize byproducts of metabolism
 free radicals (unpaired e
-
) + hydrogen peroxide  H
2
O
Breakdown and synthesize fatty acids

67. Mitochondria
Uses carbs, lipids, and proteins to synthesize ATP
Has outer and inner membranes separated by the
intermembrane space
Inner membrane carries proteins involved in ATP
production
Matrix is site of reactions that release energy from
nutrients
Mitochondria

68. Figure 3.10Figure 3.10

70. Assignment
Describe 10 structural and functional
adaptations that help mitochondria in
performing their functions.
Describe the fluid mosaic model of the cell
membrane.
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings