All living things are made of organized parts, obtain energy from their surroundings, perform chemical reactions, respond to their environment, grow and develop, change with time, and reproduce All organisms are made of cells All cells are produced from other cells (all cells arise from pre-existing cells by cell division) The cell is the most basic unit of life

1. What are characteristics of living things?
Organisation
Response to stimuli
Homeostasis (maintaining stable
internal conditions),
Change through the time…
Metabolism
Growth and development
Reproduction

2. CELL STRUCTURE ANDCELL STRUCTURE AND
FUNCTIONSFUNCTIONS

3. All living things are made of organized
parts, obtain energy from their
surroundings, perform chemical reactions,
respond to their environment, grow and
develop, change with time, and reproduce
A cell is the smallest unit that can
carry on all of the processes of life

4. Cell TheoryCell Theory
• The cell theory grew out of the work of many
scientists and improvements in the microscope.
• The cell theory is a unifying concept of biology.
• In 1665, Robert Hooke discovered cells in slices of cork.
• In 1673, Anton van Leeuwenhoek was the first to observe living cells
in microorganisms; Leeuwenhoek called these organism animalcules
(now called protists).

5. Cell Theory
• All organisms are made of cells
• All cells are produced from other cells (all cells
arise from pre-existing cells by cell division)
• The cell is the most basic unit of life

6. What is a cell?
How do cells organise in
living things?

7. Cell Diversity
Amoeba Proteus
Nerve Cell
Bacteria
Plant Stem
Red Blood Cell

8. All cells share certain characteristics
• Cells tend to be microscopic
• All cells are enclosed
by a membrane
• All cells are filled with
cytoplasm
• Unicellular organisms are made up of one cell
• Multicellular organisms are made up of many cells that
often specialize according to function - differentiation
cell membrane
cytoplasm

9. Cell Size
– Cell size is limited by a cell’s surface
area–to-volume ratio.

10. Cell size differs amongst species

11. Cell Shape
– A cell’s shape reflects its function

12. Two Types of Cells
Prokaryotic cells (without membrane-bound structures)
Eukaryotic cells (with membrane-bound structures)

14. Prokaryotic cell (‘pro’ - before, ‘karyon’ – nucleus)

15. Prokarotic cells
• Do not have a nucleus and membrane-bound organelles
• Have few internal structures
• Single, circular chromosome in nucleoid region
• Surrounded by cell membrane and a cell wall made up
of peptidoglycan
• Prokaryotic cells are one-celled
organisms: bacteria
• Divided into two domains,
i.e., Archaea and Bacteria

16. Eukaryotic cell (‘eu’ - proper, ‘karyon’ – nucleus)

17. Eukaryotic cells
• Cells have a nucleus and membrane-bound organelles
• Incudes protists, fungi, plants, and animals
• The three basic parts of a cell are the plasma
membrane, the cytoplasm, and the nucleus.

18. Prokaryotic cell Eukaryotic cell
Organisms
bacteria protists, fungi, plants,
animals
Size ~ 1-10 µm ~ 10-100 µm
Structure
• Most have a cell wall
and some have a
capsule surrounding it
• Lack nucleus and
many organelles
• Ribosomes 70S (50S
+ 30S)
• Only plant cells have cell
wall
• Has typical nucleus and
many organelles
• Ribosomes 80S (60S +
40S)
Prokaryotic cell vs. Eukaryotic cell

19. Virus
• No nucleus
• No membranes
• No organelles
• Cannot reproduce on its
own
• Generally not considered
alive by most standards
Flu virus

20. T4 Bacteriophage

21. HIV

22. A cellA cell is a basic unit of life, that is capable of
performing life functions
A cell can be
likened to a factory

23. Each part of the
cell has their own
structure and
function

24. Cell membrane
Endoplasmic
reticulum (ER)
Nucleus
Ribosome
Lysosome
Mitochondrion
Golgi body

25. Animal Cell

26. Plant Cell

27. Surrounding the Cell

28. Cell Membrane
 Cover the cell’s surface
 Act as a barrier between inside and outside of the cell
 Controls the transport of materials in and out of the cell

29. cell membrane outside cell
inside cell
Cell Membrane
• Double layer of
phospholipids that
is highly fluid
without breaking.
• Embedded
proteins in the
lipid layer and give
the membrane its
mosaic character -
fluid mosaic.
• Selectively
permeable
protein
cholesterol
protein
carbohydrate
chain
protein channel

30. Phospholipid bilayer
• The fluid portion of the membrane
• Phospholipid molecules have:
* A polar head group, hydrophilic and points
toward the aqueous environment on both sides
of the membranes
* A pair of nonpolar tails, hydrophobic and
point away from the aqueous environments
and toward each other

31. Membrane
structure

32. Phospholipid bilayer
• Establish the physical integrity of the membrane
• Create an effective barrier to the rapid passage of
hydrophilic materials such as water and ions
• Serves as a lipid “lake” in which a variety of proteins
“float”
Membranes also contain cholesterol, which is
important to membrane integrity and fluidity.
Cholesterol prevents the phospholipid from packing
tightly together, thus make the cell surface more
flexible and stable and prevents freezing in low
temperatures

33. Membrane Proteins
– Cell membranes often contain proteins embedded
within the phospholipid bilayer.
– Proteins help move large molecules or aid in cell
recognition (peripheral and integral)

34. Cell Wall
• Most commonly found in
plant cells & bacteria
• Outermost layer of a plant
cell (made of cellulose)
• Permeable, contains small
pores to move water and
oxygen and carbon dioxide
in and out.
• Maintains structure,
supports & protects the
cell

35. Inside the Cell

36. Protoplasm: a clear substance like jelly which forms the
living part of an animal or plant cell including the nucleus
Protoplasm: cytoplasm + nucleus
Cytoplasm: cytosol + many organelles
Cytoplasm: all the living material in a cell, not including
the nucleus
Organelle: a membrane-bound structure within a cell
which carries out a particular function

37. Nucleus
• Separate from cytoplasm by double membrane
• Contains genetic material - DNA
• Controls all the activities of the cell

38. Nuclear Membrane (nuclear envelope)
• Surrounds nucleus
• Made of two layers
• Pores allowing material to enter and leave nucleus
Chromosomes
 Made of DNA and proteins
 Contain instructions for traits & characteristics
 Chromatin condenses to form discrete chromosomes as
a cell prepares to divide.
Nucleolus
 The site of ribosomal RNA synthesis

39. Cytoplasm
• Jelly-like substance
• Contains organelles, cytoskeleton, fluid including
molecules (proteins, water, food and wastes)
• Medium for chemical reaction
– Cytosol includes molecules and small particles, such as
ribosomes, but not membrane bound organelles. About 20%
of the cytosol is made up of protein

40. Cytoskeleton
• Maintains cell shape and support
• Helps position and transport organelles
• Provides strength
• Assists in cell division
• Aids in cell movement

41. Cytoskeleton

42. Cytoskeleton
• Consists of microtubules, microfilaments and
intermediate filaments
• The microtubules assist in cell division by moving
the cells apart.
• Microfilaments are made of protein and help with
muscle contractions.
• Both help support the cell and give structure but do
allow for movement.

43. Cilia and Flagella
• Hairlike structures that
extend from the surface
of the cell, where they
assist in movement
• Some cells have flagella.
(usually only one)
• Many cells have cilia
(thousands)
• A flagella is like a whip.
• Cilia are like tiny
paddles.
• Cilia and flagella are
made of microtubules.
Cilia
Flagella

44. Endoplasmic Reticulum

45. Endoplasmic Reticulum
• Continuous with the nuclear membrane
• Involved in cell product transport of proteins and
lipids
• The rough and smooth ER are sometimes attach to
each other.
• Rough ER: surface covered with ribosomes and
prepares proteins for export or insertion into the cell
membrane.
– Most abundant in cells that produce large amounts of
protein for export, such as digestive glands and
antibody-producing cells

46. Endoplasmic Reticulum
• Smooth ER: lacks ribosomes and makes lipids such as
steroids participates in detoxification of toxins.
– In ovaries and testes, smooth ER produces estrogen
and testosterone, respectively
– In skeletal and heart muscle cells, smooth ER releases
calcium, which stimulates contraction
– Abundant in liver and kidneys for detoxification

47. Ribosomes
Nucleus

48. Ribosomes
• Each cell contains thousands
• Float freely in cytoplasm or attached to rough
endoplasmic reticulum
• Made of protein and rRNA. Ribosome assembly begins
in the nucleolus and is completed in the cytoplasm
• Site of protein synthesis

49. Ribosomes

50. Golgi Body
• A system of membranes
that work closely with the
ER
• Consists of flattened
membranous sacs called
cisternae
• Involves in processing,
packaging and secreting of
proteins/lipids

51. cis face
(“receiving” side of
Golgi apparatus)
trans face
(“shipping” side of
Golgi apparatus)
0.1 m
TEM of Golgi apparatus
Cisternae
The Golgi apparatus

53. Vesicle
Vesicles are membrane-bound sacs that hold materials

55. Lysosome
• Surrounded by single
membrane
• Contains hydrolytic enzyme
• Digestive 'plant' for proteins,
fats, carbohydrates and
nucleic acid as well as old
organelles, viruses and
bacteria.
• Transports undigested
material to cell membrane for
removal
• Cell breaks down if lysosomeLysosomes are rare in plant cells

57. Peroxisome
• Small organelles with
a single membrane
and a granular interior
containing specialized
enzymes
• Collect the toxic
peroxides (eg. H2O2)
that are the
unavoidable by-
products of chemical
reactions and break
them down without
mixing with other
Glyoxysome, a structurally similar organelle found only in plants
especially in young plants, are the sites where stored lipids are
converted into carbohydrates for transport to growing cells

58. Mitochondrion
• Rod-shaped organelle
with double membrane
• Produces energy (ATP)
through chemical
reactions
• Have their own DNA
which only comes from
the mother.

60. Vacuoles
• Large and permanent in
plants
• Contains sap fluid
• Storage areas for
cellular products and
substances such as
water, waste, enzymes
and poisons
• Help plant cells
maintain shape

61. Plastid
• Plastids store starch and pigments.
– Chloroplasts – contain green pigment, chlorophyll that
absorbs light energy to make carbohydrates
– Chromoplasts – contain colorful pigments
– Amyloplasts – store starch

63. Chloroplast
• Found only in plant
cells and some
protists
• Have double
membrane and
their own DNA
• Contains
chlorophyll
• Carry out
photosynthesis in
the presence of
sunlight, water and

66. Centrioles
• Only in animal cell
• Found near nucleus
• Tubes found in the
centrosomes
• Consist of two short cylinders
of microtubules at right
angles to each other
• Involved in cell division
• Centrioles form cilia and
flagella

67. Are plant cells like animal cells? With the
same structure?
A typical plant cell has a more regular and rigid
shape as compared to a typical animal cell.
They contain other organelles that are not found in
animal cells such as cell wall, chloroplasts

68. Animal Cell and Plant Cell

69. Plant Cells Vs. Animal Cells
• Contain chloroplasts for
photosynthesis
• Have a cell wall to maintain
structure and rigidity
• Centrioles are absent
• Usually do not contain
lysosomes
• Have one large central
vacuole
• Cells are square and rigid
or geometric shaped
• No chloroplasts
• No cell wall
• Centrioles are present
• Contain lysosomes
• Has small and few vacuoles
• Cells are fluid and flexible,
many shapes

70. 1. Which organelle synthesizes proteins?
A. Nucleus B. Ribosome
C. Centriole D. All above
2. Most of a cell's ATP is synthesized by membrane-bound
organelles called
A.Vacuole B. Ribosome
C. Mitochondria D. Nucleus
3. Which organelle modifies, packages, and sorts proteins
for secretion or use within the cell?
A. Mitochondria B. Golgi body
C. Nucleus D. Endoplasmic
reticulum

72. In Humans

73. In Plants

74. Cell
↓
Tissue
↓
Organ
↓
System
↓
Organism

75. How big is a cell?

76. Kính hiển vi quang học
Kính hiển vi điện tử
Tế bào trứng cá
Đa số
tế bào thực vật
và
động vật
Lục lạp
Đa số vi khuẩn
Phage T2
Lipits
Proteins
Nguyển tử
Các phân tử nhỏ
Cell size

77. The Microscope in Cell Studies
• 2 different types of microscopes:
i) light microscope – uses light as a source of
radiation
ii) electron microscope – uses electrons
UNSWFYBIO/2008JK

78. Magnification and Resolution
• Magnification
- the number of times larger an image is compared
with the real size of the object
- magnification = size of image
actual size of specimen
• Resolution
- the ability to distinguish between two separate
points
UNSWFYBIO/2008JK

79. Light microscope

80. Electron microscope

81. Electron microscope

82. Comparison of advantages and disadvantages of the
light and electron microscope
LIGHT MICROSCOPE ELECTRON MICROSCOPE
Advantages Disadvantages
Cheap to purchase Expensive to purchase
Cheap to operate – uses a little electricity where
there is a built-in light source
Expensive to operate – requires up to 100 000
volts to produce the electric beam
Small and portable Very large and must be operated in special
rooms
Unaffected by magnetic fields Affected by magnetic fields
Preparation of material is relatively quick and
simple, requiring only a little expertise
Preparation of material is lengthy and requires
considerable expertise and sometimes complex
equipment
Material rarely distorted by preparation Preparation of material may distort it
Living as well as dead material may be viewed A high vacuum is required and living material
cannot be observed
Natural colour of material can be observed All images are in black and white
Disadvantages Advantages
Magnifies objects up to 1500X Magnifies objects over 500 000X
Can resolve objects up to 200 nm apart Has a resolving power for biological specimens
of around 1 nm
The depth of field is restricted It is possible to investigate a greater depth of
field