The document provides an overview of cell structure and function. It defines the cell and outlines the cell theory. The major components of plant cells are described, including organelles like the nucleus, chloroplasts, mitochondria, and cell membrane. It also discusses the cytoskeleton and movement of substances across the cell membrane through passive diffusion, facilitated transport, osmosis, and active transport processes like endocytosis and exocytosis. The overall purpose is to introduce learners to key aspects of cell biology.

1. CELL STRUCTURE AND FUNCTION
Presented by:
Fasama Hilton Kollie
Lecturer, Department of Biology
Mother Patern College of Health Sciences
CHP’T-2
September 17, 2018

2. LESSON OUTLINE
1. Overview of cell
• Definition and Discovery of the cell
• Cell Theory and Principle of the Cell Theory
• Characteristic of Cell
• Types of Cell
2. Major Plant Cell Organelles
• Overview of Organelles (Bacteria-like & Membranous Organelles)
• Nucleus, Ribosomes, Endoplasmic Reticulum, Golgi Apparatus,
Chloroplast, Mitochondria, Cytoplasm, Microbodies, Vacuole…

3. 3. Cytoskeleton
• Overview of cytoskeleton
• Microtubules, Microfilaments, Motor proteins
• Intermediate Filament
4. Membrane and Cell Wall
• Cell membrane
• Cell wall
LESSON OUTLINE CONT.

4. 5. Movement Across Cell Membrane
• Passive Transport
• Simple diffusion
• Facilitated diffusion
• Osmosis
• Hypotonic, Isotonic and Hypertonic solutions
• Active Transport
• Endocytosis
• Pinocytosis and Phagocytosis
• Exocytosis
LESSON OUTLINE CONT.

5. LESSON OBJECTIVE
• By the end of this session, the learners will be able to;
1. Define cell, cell theory, and organelle
2. Demonstrate plant and animal cell
3. Identify and describe the major plant cell organelles
4. Discuss cytoskeleton
5. Describe plant cell wall and membrane
6. Describe the movement of substance across the cell
membrane

6. What is cell?

7. CELLS
• From latin - cella, meaning "Small
room“
• The basic structural, functional, and
biological unit of all known living
organisms
• Often called the "building blocks of life"Plant cells

8. DISCOVERY OF CELLS
• Robert Hooke (Mid-1600s)
̶ Observed sliver of cork
̶ Saw “row of empty boxes”
̶ Coined the term “Cell”

9. CELL THEORY
• Matthias Schleiden (1838)
All plants are made up of cell
Schleiden
Schwann
Virchow
• Theodor Schwann (1839)
All animals are made up of cell
• Rudolf Virchow (1855)
All cells comes from preexisting
cells

10. PRINCIPLES OF CELL THEORY
1. All living things are made of one or more cells
2. The Cell is the smallest living unit of structure and function of
all organisms
3. All cells arise from preexisting cells through cell division
Schleiden SchwannVirchow

11. Cell Size
CHARACTERISTICS OF CELL

12. Cells Have Large Surface Area-to-Volume Ratio

13. Cell Shape
• A cell’s shape reflects its function
Bacteria cell
Plant cell
Red blood cell

14. CELL TYPES
1.Prokaryotic
2.Eukaryotic

15. PROKARYOTIC CELLS
• First form of life on earth
• Single-celled organisms
• Cell type of bacteria and archaea
• A prokaryotic cell contain three
architectural regions:
̶ Cell envelop
̶ Cytoplasmic region
̶ Flagella and pili

16. PROKARYOTIC CELLS
• Lack membrane-bound organelles
• Nucleoid :region of DNA
concentration
• Most are the smallest of all
organisms ranging from 0.5 – 2.0
µm in diameter

17. EUKARYOTIC CELLS
• Nucleus bound by
membrane
• Include fungi, protist,
plant, and animal cells
• Possess many organelles
Animal cell

18. Representative Animal Cell

19. Representative Plant Cell

20. CHARACTERISTICS OF ALL
CELLS
• Contain a surrounding membrane (plasma membrane)
• Protoplasm – cell contents in thick fluid
• Control center with DNAs

21. Plasma
Membrane
Nucleus
(DNA)
Protoplasm
Organelles
CHARACTERISTICS OF ALL CELLS CONT.

22. MAJOR PLANT CELL ORGANELLES
• “Little organs”
• Specialized subunit within a cell
that has specific function
• Cellular machinery
• Two general kinds:
̶ Bacteria-like organelles
̶ Derived from membranes

23. Bacteria-Like Organelles
• Derived from symbiotic bacteria
• Ancient association
• Endosymbiotic theory
̶ Evolution of modern cells from
cells & symbiotic bacteria

24. • Release & store energy
• Types:
̶ Mitochondria
(release energy)
̶ Chloroplasts
(store energy)
Bacteria-Like Organelles
Mitochondria
Chloroplast

25. Cytoplasm
• Viscous fluid containing organelles
• Components of cytoplasm:
̶ Interconnected filaments & fibers
̶ Fluid = cytosol
̶ Organelles (not nucleus)
̶ Storage substances (Examples)
Cytoplasm

26. Membranous Organelles
• Functional components within cytoplasm
• Bound by membranes
̶ Nucleus
̶ Ribosomes
̶ Endoplasmic reticulum
̶ Golgi Apparatus
̶ Lysosomes
̶ Vacuole
̶ Microbodies

27. Nucleus
• Control center of cell
• Double membrane
• Contains:
̶ Chromosomes (DNA)
̶ Nucleolus
̶ Nuclear envelop
̶ Nuclear pole

28. Nucleus and It’s Components
Nucleus
1. Nuclear envelop
• Outer membrane
• Inner membrane
2. N
3. Chromatin
4. Nucleolus
5. Nuclear pore
Nuclear envelop
Nucleoplasm
Chromatin
Nucleolus
Nuclear pole

30. • Site of protein synthesis
• Usually exit in large numbers in
living cells
Ribosomes
• Organelles that direct the synthesis of
proteins using genetic instruction in the
form of messenger RNA
Ribosomes

31. • Free ribosomes
• Suspended in the cytosol
• Synthesize proteins that function in cytosol
Types of Ribosomes
Free Ribosomes
Bound Ribosomes
• Bound ribosomes
• Attached to endoplasmic reticulum
• Synthesize proteins for export or for
membranes
• Proteins work within endomembrane system or
outside cell

32. • Network of interconnected
membranes
• Helps move substances within cells
• Serves as assembly site for making
proteins, lipids …
• Two types;
– Rough Endoplasmic Reticulum
– Smooth Endoplasmic Reticulum
Endoplasmic Reticulum
ER

33. • Ribosomes attached to surface
̶ Manufacture protein
̶ Contain cisternae
• May modify proteins from
ribosomes
Rough Endoplasmic Reticulum
Rough ER

34. Smooth Endoplasmic Reticulum
• No attached ribosomes
• Has enzymes that help build
molecules
̶ Carbohydrates
̶ Lipids
Smooth ER

35. Golgi Apparatus
• A complex of vesicles and folded
membranes involved in secretion and
intracellular transport
• Transport vesicles
• Consist of stacks of cisternae, known as Golgi
stacks
• Consist of two main networks:
̶ Cis Golgi Network (CGN)
̶ Trans Golgi Network (TGN)

36. 1. It modify, sort and package the
macromolecules that are synthesized
by the cell
2. They are also involved in the transport
of lipid molecules around the cell
3. It is also a major site of carbohydrate
synthesis
Golgi Apparatus Function

37. Molecules Transport Via GA

39. Lysosomes
• Spherical vesicles that contain
hydrolytic enzymes that can break
down many kinds of biomolecules
• Contain digestive enzymes
• Functions:
̶ Aid in cell renewal
̶ Break down old cell parts
̶ Digests invaders

40. • Membrane bound storage sacs
• Single membrane structure
• Contents:
̶ water, food, wastes, enzymes
• Function:
̶ Isolating harmful materials
̶ Storing waste products
̶ Storing valuable water in a plant cell
̶ Balancing the ph of a cell
̶ Storing proteins for seed
germination
Vacuole

41. • Single membrane–enclosed organelles
• Found in cells of plants, protozoa, and animals
• Usually a vesicle with spherical shape
• Constitute: peroxisomes, glyoxysomes…
• Function:
̶ Contain enzymes that participate in biochemical reactions in cells
̶ Detoxification of peroxides
̶ Photorespiration in plants
Microbodies

42. Chloroplasts
• Organelle within the cells of plants and
green algae that is the site of
photosynthesis
• Contains green chlorophyll pigment
• Double membrane structure
• Chloroplast is a type of plastid
̶ Include leucoplasts and
chromoplasts

43. Chloroplast Cont.
• Endosymbiotic theory explains
the origin of chloroplast
̶ Which has a two
membranes and;
̶ A small circular
chromosome

44. Endosymbiotic
Theory

45. Mitochondria
• Organelles that are the cell’s “power plant”
• It breaks down sugar to store its chemical
energy in ATP
• Consist of;
̶ Double membrane, Matrix, Thylakoids,
̶ Stoma, Mitochondria DNA
• Production of energy for cell is its most
prominent function

46. CYTOSKELETON
• Filaments & fibers
• Made of 3 fiber types
̶ Microtubules
̶ Microfilaments
̶ Intermediate filaments
• 3 functions:
̶ Mechanical support
̶ Anchor organelles
̶ Help move substances

47. • Long hollow tubes in the cytoskeleton
• Made up of a protein called Tubulin
• Function;
• Helps maintain cell shape
• Movement of multicellular
organisms through water
– Cilia and Flagella
• All movement controlled by microtubules
involves “walking molecules”
Microtubules:

48. Cilia & Flagella
Cilia:
• Short hair-like projections
• Used to move substances outside
human cells
Flagella:
• Whip-like extensions
• Found on sperm cells

49. • Made up of globular protein called
actin
• Function:
→ Helps living cell change shape
→ Help in the movement of cell
content around the vacuole in a
circular motion known as
cytoplasmic streaming
Microfilaments:

50. • A type of cytoskeletal elements
made of multiple strands of fibrous
proteins wound together
• Average diameter of 8-10nm
• Function:
→ Help in holding the nucleus in
its permanent position
→ Control the shape of the
nucleus
Intermediate Filaments:

51. • “Walking molecule”
• Motor proteins require
energy for movement
• Involve in many movement
in cells
• These include;
̶ Chloroplast moving from
the bottom to the side of a
cell
̶ Cyclosis
Motor Proteins

52. • “ Plasma membrane”
• Membranes are barriers that
control what enters and leaves the
cell
• Fluid mosaic model provides a
broader description of the cell
membrane
MEMBRANES AND CELL WALLS
Cell Membrane:

53. Fluid Mosaic Model

54. • Protective layer that surrounds the
plasma membrane
• Plant cell wall consist primary of
cellulose
• Plant cell wall consist of two
components:
̶ Primary cell wall
̶ Secondary cell wall
Cell Wall

55. MOVEMENT ACROSS CELL MEMBRANES
1. Passive Transport
2. Active Transport
3. Endocytosis
Phagocytosis & Pinocytosis
4. Exocytosis

56. Passive Transport
• No energy required
• Move due to gradient
• Movement is down the concentration
gradient
̶ High moves toward low
• Consist of 3 types:
̶ Simple Diffusion
̶ Facilitated diffusion
̶ Osmosis

57. Simple Diffusion:
• Molecules move to equalize concentration

58. • Movement of specific molecules down a concentration gradient
• Pass through membranes via specific carrier protein
• Selection is by size, shape, charge
Facilitated Diffusion:

59. • Channels (are specific) help molecule or ions enter or leave the cell
Facilitated Diffusion Cont.
• Channels usually are transport
proteins
• (Aquaporin facilitate the movement
of water)

60. Process of Facilitated Transport

61. Osmosis:
• Special form of diffusion
• Fluid flows from lower
solute concentration to
higher
• Requires selective
permeable membrane

62. Solvent + Solute = Solution
• Hypotonic
̶ Solutes in cell more than outside
̶ Outside solvent will flow into cell
• Isotonic
̶ Solutes equal inside & out of cell
• Hypertonic
̶ Solutes greater outside cell
̶ Fluid will flow out of cell
Solution Difference & Cell

63. Effect of Osmosis On Cells

64. Active Transport
• Molecular movement
• Requires energy (against concentration gradient)
• Eg: Sodium-potassium
pump

65. Endocytosis
• Movement of large material
– Particles, organisms ,large
molecules
• Movement is into cell
Cytoplasm
Vesicle
Outside cell

66. Forms of Endocytosis
• Phagocytosis – “cell eating”
• Pinocytosis – “cell drinking”

67. Exocytosis
• Reverse of endocytosis
• Cell discharges material

68. REFERENCE
• Nabor, Murray W., INTRODUCTION TO BOTANY, Copyright 2004 Pearson
Education, Inc., publishing as Benjamin Cummings, 1301 Sansome St., San
Francisco, CA 94111
• Kingsley R. Stern, James E. Bidlack & Shelley H. Jansky.,
INTRODUCTORY PLANT BIOLOGY, Copyright © 2008 by The McGraw-
Hill Companies, Inc. Published by McGraw-Hill, 1221 Avenue of the
Americas, New Yours, NY 10020. www.mhhe.com
• Movement across membranes
http://www.biologymad.com/resources/diffusionrevision.pdf
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