chapter 1 - cell as a basic unit of life - part 1
DESCRIPTION
NoteTRANSCRIPT
OBJECTIVES
• By the end of the lesson, students should be able to :1.Explain 4 basic principles in Cell Theory– Describe the cell as the smallest
independent unit of life & form the basis of living organism.
2. Prokaryotic and eukaryotic cells– Describe & compare the structure of
prokaryotic cell & eukaryotic cell
•All organisms are composed of one or more cells.
Semua benda hidup berasal daripada sel.
1.1) Cell Theory
1
Sel ialah unit asas kehidupan.
•Cells are the “basic unit of life”.
Lesson Objective:
1.Explain 4 basic principles in Cell Theory1.0 CELL AS A UNIT OF LIFE
•New cells are produced from the earlier cells (mother cells)/pre existing cell through cell division.
Sesuatu sel baru berasal daripada sel yang terdahulu melalui pembahagian sel.
2
Lesson Objective:
1.Explain 4 basic principles in Cell Theory1.0 CELL AS A UNIT OF LIFE
•Cell is a unit in which all metabolic processes take place.
Sel berfungsi sbg satu unit di mana semua proses metabolisme berlaku di dalamnya.
3
Lesson Objective:
1.Explain 4 basic principles in Cell Theory1.0 CELL AS A UNIT OF LIFE
•Each cell carries heritable/genetic information that can be passed on to the daughter cells during the cell division. Setiap sel mempunyai maklumat
genetik/pewarisan yang boleh diturunkan kepada sel anak semasa pembahagian sel.
4
Lesson Objective:
1.Explain 4 basic principles in Cell Theory1.0 CELL AS A UNIT OF LIFE
1.2) Prokaryotic and eukaryotic cells
Prokaryotic Cell
e.g. bacteria, cyanobacteria (blue-green algae)
pro- = early(before), primitive, first karyo- = nucleus
prokaryotic cell =
cell that bears primitive nucleus, or nuclear material that is not enclosed by
nuclear membrane
prokaryotic organisms prokaryotes
?
Lesson Objective:
2. Prokaryotic and eukaryotic cells1.0 CELL AS A UNIT OF LIFE
• A major difference between prokaryotic and eukaryotic cells is the location of chromosomes.
• In an eukaryotic cell, chromosomes are contained in a membrane-enclosed organelle, the nucleus.
• In a prokaryotic cell, the DNA is concentrated in the nucleoid without a membrane separating it from the rest of the cell.
BACK
Lesson Objective:
2. Prokaryotic and eukaryotic cells1.0 CELL AS A UNIT OF LIFE
(1.2) Prokaryotic Cell Typical Structure (i)
capsulepili
cell wall
plasma membrane
stored foodDNA without nucleo envelope
flagellum
cytoplasm
polysomes
ribosomes
MesosomeCarry out respiration
Lesson Objective:
2. Prokaryotic and eukaryotic cells1.0 CELL AS A UNIT OF LIFE
(1.2) Prokaryotic Cell Typical Structure (ii)
Lesson Objective:
2. Prokaryotic and eukaryotic cells1.0 CELL AS A UNIT OF LIFE
Prokaryotic Cells
Lesson Objective:
2. Prokaryotic and eukaryotic cells1.0 CELL AS A UNIT OF LIFE
(1.2) Prokaryotic Cell
Typical Features
•small (diameter: 0.5 - 10m)•cytoplasm surrounded by a plasma membrane and•encased within a rigid cell wall •no distinct interior compartment•nuclear material: DNA•no membrane bound organelles•contain simple structures like ribosome•membrane folds contain pigments for photosynthesis
Lesson Objective:
2. Prokaryotic and eukaryotic cells1.0 CELL AS A UNIT OF LIFE
(1.2) Prokaryotic Cell
Typical Features (Cell walls)
•composed of peptidoglycan* •protect the cell •maintain its shape•prevent excessive water uptake
peptidoglycan* •consists of a carbohydrate matrix that is cross-
linked by short polypeptide units •characterizes different types of bacteria:
Gram positive and Gram negative
Lesson Objective:
2. Prokaryotic and eukaryotic cells1.0 CELL AS A UNIT OF LIFE
(1.2) Prokaryotic Cell
Typical Features (Flagella)•some bacteria use a flagellum for locomotion and feeding•long, threadlike structures•protruding from the surface of the cell•move in rotation (why?)
Lesson Objective:
2. Prokaryotic and eukaryotic cells1.0 CELL AS A UNIT OF LIFE
(1.3) Eukaryotic Cell
e.g. Protoctists;protozoa cells, plant cells, fungus cells, animal cells, algae,
eu- = true/after karyo- = (something to do with)
nucleus eukaryotic cell =
cell that bears true nucleus, or nuclear material that is enclosed by a nuclear
membrane
eukaryotic organisms eukaryotes?
1.0 CELL AS A UNIT OF LIFELesson Objective:
2. Prokaryotic and eukaryotic cells
Eukaryotic Cell Typical Structure (i)
cytoplasm
plasma membrane
nucleus
nuclear membrane
nucleoplasmachromatinnucleolus
mitochondrion
Golgi apparatuscentrosome
temporary small vacuole
secretive granules
protoplasm
Cytoplasm
1.0 CELL AS A UNIT OF LIFELesson Objective:
2. Prokaryotic and eukaryotic cells
Typical Features•diameter: 10 - 100m)•within the cytoplasm is a variety of membrane bounded organelles of specialized forms and functions (compartmentalization)•nuclear material: DNA + proteins•contain vesicles, small sacs that store and transport a variety of materials•supported by internal protein scaffold, cytoskeleton
A network of fibers permeating the matrix of eukaryotic cell that provides a supporting frame work for organells, organells movements etc
1.0 CELL AS A UNIT OF LIFELesson Objective:
2. Prokaryotic and eukaryotic cells
• In eukaryote cells, the chromosomes are contained within a membranous nuclear envelope.
• The region between the nucleus and the plasma membrane is the cytoplasm.– All the material (organelles) within the plasma
membrane is known as cytoplasm.
• Within the cytoplasm of a eukaryotic cell is a variety of membrane-bounded organelles of specialized form and function.
• These membrane-bounded organelles are absent in prokaryotes.
1.0 CELL AS A UNIT OF LIFELesson Objective:
2. Prokaryotic and eukaryotic cells
The Differences between Prokaryotic and Eukaryotic Cell. Prokaryotic
Cell size
(2.2) Prokaryotic Cell
Eukaryotic Cell small (0.5-10.0)
larger (10 -100)
true nucleus absent present*
chromosome circular helix DNA
linear helix DNA with histone prot.
cell wall peptidoglycan cellulose ribosomes small large
cytoskeleton absent presentflagella helix flagellin &
lack of microtubule. microtubules (9+2) structure
1.0 CELL AS A UNIT OF LIFELesson Objective:
2. Prokaryotic and eukaryotic cells
Cell / organism size compare to Organism Sizes• Most cells are much smaller than one millimeter.
– Some as small as one micrometer.
• Small cells are likely to have an adequate surface area for exchanging wastes for nutrients.
– Cells that specialize in absorption have modifications that greatly increase the surface area per volume of the cell.
1.0 CELL AS A UNIT OF LIFELesson Objective:
2. Prokaryotic and eukaryotic cells
1.3) Microscopic Structure of Plant & Animal Cells
OBJECTIVES
• By the end of the lesson, students should be able to :
- Illustrate the detailed structures of typical plant & animal cells.
- Compare between plant & animal cells
1.3) Structure of animal & plant cells
1.0 CELL AS A UNIT OF LIFELesson Objective:
Illustrate the detailed structures of typical plant & animal cells.
ANIMAL CELLS• As seen under light microscope, animal cells
contain protoplasm (nucleus + Cytoplasm )• Cytoplasm=cytosol+organelles)• Large central nucleus surrounded by cytoplasm.• Nucleus contains coiled DNA called Chromatin +
protein called histone. • Cytoplasm contains;organelles & glycogen
granules (food storage polysaccharide)• Have either small vacuole or none at all.
1.0 CELL AS A UNIT OF LIFELesson Objective:
Illustrate the detailed structures of typical plant & animal cells.
Typical Structure (ii): Plant Cells
middle lamella
1.0 CELL AS A UNIT OF LIFELesson Objective:
Illustrate the detailed structures of typical plant & animal cells.
Plant cells• Protective, rigid, cellulose cell wall
surrounding the cell.
• Chloroplasts in the cytoplasm contain chlorophyll pigments which carry out photosynthesis.
• Large vacuole. Central vacuole, filled with sap (photosynthesis product)
• Contain starch granules
1.0 CELL AS A UNIT OF LIFELesson Objective:
Illustrate the detailed structures of typical plant & animal cells.
The Differences between Plant and Animal Cells (i)
Plant Cells shape
Animal Cells
rigid not rigid lysosomes usually absent present
chloroplasts in photosynthetic cells
absent
cell wall plasmodesmata middle lamella
absent
1.0 CELL AS A UNIT OF LIFELesson Objective:
Compare between plant & animal cells.
The Differences between Plant and Animal Cells (ii) Plant Cells Animal Cells
vacuoles large contain cellular fluid tonoplast
too small @ absent
centrioles absent, except in more primitive plants
present
stored carbohydrat
e
starch glycogen
cilia absent, except in more primitive plants
present
1.0 CELL AS A UNIT OF LIFELesson Objective:
Compare between plant & animal cells.