3. All things on earth can be classified into
2 groups. Can you group these items
into these 2 main groups?
LIVING or NON LIVING
4. All things on earth are either
living or non-living.
non-living
So... What makes living things different from Non-
living things? Let’s see
5. There are 7 characteristics:
• Movement
• Respiration
• Sensitivity
• Growth
• Reproductio
n
• Excretion
• Nutrition
6. Movement
• An action by an organism or part of an
organism causing a change of position or
place.
7. Respiration
• The chemical reactions that break down
nutrient molecules in living cells to release
energy (break down + O2)
Respiration
is NOT
*gaseous
exchange
*BREATHING
8.
9. Sensitivity
• The ability to detect or sense changes in
the environment (stimuli) and to make
responses (react to them)
10. Growth
• A permanent increase in size and dry
mass by an increase in cell number or cell
size or both.
12. Excretion
• The removal from organisms of toxic
materials, the waste products of
metabolism (chemical reactions in cells
including respiration) and substances in
excess of requirements.
13. Nutrition
• The taking in of
nutrients (from
environment)which are
organic substances
and mineral ions,
containing raw
materials or energy for
growth and tissue
repair, absorbing and
assimilating them.
14. Quiz
Guess which characteristic is being
demonstrated by the following animations:
21. Question 7
So far you should have
named a total of five
different characteristics.
However there are 7
characteristics in total.
Name the two remaining
characteristics.
36. CELL THEORY
1. The basic unit of life is the cell. (Hooke)
• In 1665, an English scientist
named Robert Hooke made
an improved microscope and
viewed thin slices of cork
viewing plant cell walls
• Hooke named what he saw
"cells"
Slide from: http://www.worldofteaching.com
37. CELL THEORY
2. All living things are made of 1 or more cells.
• Matthias Schleiden (botanist studying plants)
• Theodore Schwann (zoologist studying
animals) stated that all living things were
made of cells
Slide from: http://www.worldofteaching.com
Schwann
Schleiden
38. CELL THEORY
3. All cells divide & come from old cells. (Virchow)
Virchow
39. Prokaryotes and Eukaryotes CELLS
Eukaryotic cell = with nucleus
Prokaryotic cell = without nucleus
BACTERIA
Prokaryotic cell
Cell membrane
Eukaryotic cell
Cytoplasm
Cell membrane
Cytoplasm
Organelles
Nucleus
40. Eukaryotic
• Contain organelles surrounded by membranes
• Most living organisms
Plant Animal
http://library.thinkquest.org/C004535/eukaryotic_cells.html
41. What are the main parts of a cell?
• Cell membrane
• Cytoplasm
• Nucleus
49. A section through a liver cell (animal
cell):
cell membrane nucleus
controls what contains the
enters and DNA and so
leaves the cell controls the cell
cytoplasm DNA
metabolic contains the
(chemical) coded
reactions instructions to
occur here make proteins
50. Section through a palisade cell of a leaf
(plant cell)
chloroplast
cell membrane
Site of
photosynthesis
large sap vacuole
nucleus
Storage of
nutrients and
waste products.
cellulose cell wall
cytoplasm Provides
protections and
support for cell
51. Comparing animal and plant cells
Found in both animal Found only in plant
and plant cells cells
cell membrane cellulose cell wall
nucleus large sap vacuole
cytoplasm chloroplast
52. 13
Plant and animal cells
• All cells have cytoplasm, a nucleus and a
cell membrane.
• Plant cells have also a cell wall, a central
vacuole and in many cases, chloroplasts.
• Animal cells do not have these structures
55. Red blood cells transport oxygen
cell surface membrane cytoplasm contains
no nucleus
allows more room for
haemoglobin
cytoplasm contains
haemoglobin
haemoglobin is a
protein which carries bi-concave disc shape
the oxygen molecules increases surface area
over which absorption of
oxygen can occur
56. Muscle cells contract and enable
movement of the body
muscle
Muscle cells have
many nuclei
cell surface membrane
nucleus
The strands of protein
slide over each other
making the muscle cell
(fibre) shorter and causing
the muscle to contract
protein strands
57. Ciliated cells move bacteria and dust
away from the lungs
cilia
Cilia are small extensions of
the cell. They beat rhythmically
to sweep mucus, which has
trapped bacteria and dust,
away from the lungs
nucleus
magnification X3000
58. Xylem vessels transport water and
minerals up the plant
xylem vessels are continuous tubes
xylem vessel
no cytoplasm
hollow: allows for
continuous flow of water
and dissolved mineral
ions
lignin
water-proof and strong;
helps support the plant
cross-section longitudinal section
59. Root hair cells absorb minerals and
water from the soil
Cross-section of a root hair cell
cell membrane semi-permeable, so will
allow water and mineral
cytoplasm ions into the cell
contains no
chloroplasts as no
photosynthesis is
needed
root hair cell
increases surface area for absorption
of water and mineral ions
61. A tissue is a group of cell of similar
structure that form a shared function
Tissues found in the leaf Animal tissues:
muscle tissue
upper epidermal
tissue
palisade mesophyll
tissue
spongy mesophyll nervous tissue
tissue
lower epidermal
tissue
Cross-section of a leaf
62. An organ is a structure made of a
group of tissues working together to
perform specific functions
heart lungs liver
stomach brain kidneys
Plant organs include the stem and the leaves
63. An organ system is a group of organs that
coordinate to perform related functions
lymphatic digestive reproductive skeletal endocrine
system system system system system
respiratory excretory muscular nervous circulatory
system system system system system
In plants the shoot is an organ system consisting of leaves and the stem
64. Levels of organisation
cell tissue organ organ organism
systems
nerve cell nervous brain nervous Homo sapiens
tissue system
smallest largest
65. 15
Organs, cells and tissues
The stomach is an
organ, part of the
digestive system
The stomach wall contains muscle
tissue
The muscle tissue consists of
muscle cells
66. 4
A group of cells from
animal tissue
cell membrane
cytoplasm nucleus
69. 7
Cell membrane
The cell membrane encloses the
cytoplasm and stops it flowing out
It also controls which substances
can get into and out of the cell
It is only about 0.00001mm thick
Double layer
cell membrane
If it is damaged, the cell will die
70. Cell Wall
• Most commonly found
in plant cells &
bacteria
• It is made of
cellulose.
• It supports & protects
cells
http://library.thinkquest.org/12413/structures.html
73. 5
Cytoplasm
The cytoplasm is a living,
semi-liquid material cytoplasm
Although it looks structureless
it contains many structures
which are not visible at this
magnification
All the processes which keep
the cell alive, take place in the
cytoplasm or nucleus
74. Cytoskeleton
- Composed of
microtubules
- Supports cell and
provides shape
- Aids movement of
materials in and out of
cells
http://library.thinkquest.org/12413/structures.html
75. 6
Nucleus
*The nucleus is a specialised region
of cytoplasm which regulates all
the chemical changes which take nucleus
place in the cytoplasm
*It sends chemical signals to the
cytoplasm which start or stop the
chemical processes going on in it
*The nucleus also controls cell division
*Separated from cytoplasm by nuclear
membrane
Contains genetic material - DNA
76. Nuclear Membrane
• Surrounds nucleus
• Made of two layers
• Openings allow
material to enter and
leave nucleus
http://library.thinkquest.org/12413/structures.html
77. Chromosomes
• In nucleus
• Made of DNA
• Contain instructions
for traits &
characteristics
http://library.thinkquest.org/12413/structures.html
79. Endoplasmic Reticulum
• Moves materials around
in cell
• Smooth type: lacks
ribosomes
• Rough type (pictured):
ribosomes embedded in
surface
http://library.thinkquest.org/12413/structures.html
80. Ribosomes
• Each cell contains
thousands
• Make proteins
• Found on ribosomes
& floating throughout
the cell
http://library.thinkquest.org/12413/structures.html
81. Mitochondria
• Produces energy through
chemical reactions –
breaking down fats &
carbohydrates
• Controls level of water and
other materials in cell
• Recycles and decomposes
proteins, fats, and
carbohydrates
http://library.thinkquest.org/12413/structures.html
82. Golgi Bodies
• Protein 'packaging
plant'
• Move materials within
the cell
• Move materials out of
the cell
http://library.thinkquest.org/12413/structures.html
83. Lysosome
• Digestive 'plant' for
proteins, fats, and
carbohydrates
• Transports undigested
material to cell
membrane for removal
• Cell breaks down if
lysosome explodes
http://library.thinkquest.org/12413/structures.html
84. Vacuoles
• Membrane-bound
sacs for storage,
digestion, and waste
removal
• Contains water
solution
• Help plants maintain
shape
http://library.thinkquest.org/12413/structures.html
85. Chloroplast
• Usually found
in plant cells
• Contains green
chlorophyll
• Where
photosynthesis
takes place
http://library.thinkquest.org/12413/structures.html
86. Centrioles
• Centrioles are found in
animal cells and help to
organize the assembly
of microtubules during
cell division.
88. 9
Plant cells
nucleus
cytoplasm
vacuole
cell wall
Plant cells differ from animal cells in having a cell wall
outside the cell membrane, and a large, fluid-filled vacuole
90. 17
Question 1
Which of these structures controls cell
division?
• Cytoplasm
• Nucleus
• Cell membrane
• Cell wall
91. 18
Question 2
In a plant cell, which of these describes the
vacuole?
• A semi-liquid living material
• A specialized region of cytoplasm
• A region containing chloroplasts
• A solution of salts and sugars
92. 19
Question 3
The cell structure which controls the entry or
exit of substances is
• the nucleus
• The cell wall
• The cell membrane
• The cytoplasm
93. 20
Question 4
Which one of these statements is correct?
•Plant cells do not have cell walls
•Plant cells have no vacuoles
•Plant cells have nuclei
•All plant cells have chloroplasts
1-striated muscle cells 2-macrophage engulfing a bacterium 3- plant cell 4- nervoes cell 5- red blood cell 6- stem cell
There are exceptions to these general statements. Red blood cells, for example, do not have a nucleus. Animal cells often have vacuoles but these are small and scattered throughout the cytoplasm.
Very few tissues consist of a single cell type. There are usually nerve fibres and blood vessels supplying the tissue
All cells consist of cytoplasm, nucleus and a cell membrane. The next three slides explain the function of each of these
A cell needs to take up oxygen and food substances to keep it alive. The cell membrane allows these substances to pass into the cytoplasm but keeps unwanted, and possibly harmful, substances out.
Under the ordinary microscope, the cytoplasm appears to be a semi-liquid gel. In some plant cells it can be seen streaming around the cell. Small particles and granules can be observed in the cytoplasm but, under higher magnification, a complex arrangement of microscopic tubules and vacuoles is revealed. These structures enable the chemical reactions, which make the cell alive, to take place in an orderly and controlled manner
The nucleus contains a substance called DNA. This substance controls what kind of a cell is produced, such as a liver cell, muscle cell or blood cell. Chemicals produced by the DNA escape from the nucleus and regulate all the chemical reactions in the cytoplasm. Cells without a nucleus cannot divide.
These cells have been scraped from the inside of the cheek. They are not .stained but viewed by a special type of lighting. The magnification on the print-out is about x 950
The cell membrane is pressed up against the inside of the cell wall by the pressure of the vacuole and is difficult to see.. The cell wall is made of cellulose . It is permeable , that is, it lets water and dissolved substances pass in and out freely. The vacuole contains a solution of chemicals such as salts, sugars and, sometimes, coloured substances (pigments). This solution is called ‘cell sap’. Its outward pressure on the cell wall keeps the cell firm.
These cells are from a moss leaf. The magnification on this page is about x400. Chloroplasts contain a green pigment, chlorophyll , which absorbs sunlight and helps the plant to make its food