Introduction to Cells Cell Theory Cell Organelles Organization

Introduction to Cells Cell Theory ~ Cell Organelles ~ Organization

Review of Cell Theory Principles of Cell Theory: All living things are made of cells. Cells carry out the functions needed to support life. Cells come only from other living cells.

Review of Cell Theory Contributing Scientists Anton von Leeuwenhoek: Invented the microscope and observed tiny living things in water Robert Hooke: Coined the term “cell” after observing that cork consisted of tiny chambers Louis Pasteur: Discovered that cells come only from other living cells

Cell Introduction Two types of cells Prokaryotic Cell Eukaryotic Cell

Cell Introduction Two types of cells Prokaryotic Cell • First cells to evolve • No nucleus • Hereditary info is contained within cytoplasm – nucleoid region Ex: Archaea, Bacteria

Cell Introduction Two types of cells Eukaryotic Cell • Evolved from prokaryotes • Have a nucleus • Hereditary info is contained within the nucleus • Ex: Animals, Protists, Fungi, Plants

Cell Introduction Cells can only be observed under microscope Two basic types of eukaryotic cells: Animal Cell Plant Cell

ORGANELLES IN CELLS Plant Cell • Cell wall Made of cellulose which forms very thin fibres Strong and rigid In plant cells only

ORGANELLES IN CELLS Plant Cell • Cell wall – Protect and support the enclosed substances (protoplasm) – Resist entry of excess water into the cell – Give shape to the cell

ORGANELLES IN CELLS Plant Cell • Cell wall – A dead layer – Large empty spaces present between cellulose fibers freely permeable

ORGANELLES IN CELLS Plant Cell • Cell membrane – Lies immediately against the cell wall – Made of protein and lipid – Phospholipid Bilayer – Hydrophobic tails and hydrophylic heads

ORGANELLES IN CELLS Plant Cell • Cell membrane – A living layer – Can control the movement of materials into and out of the cell Selectively permeable

ORGANELLES IN CELLS Plant Cell • Cytoplasm – Jelly-like substance enclosed by cell membrane – Provide a medium for chemical reactions to take place

ORGANELLES IN CELLS Plant Cell • Cytoplasm – Contains organelles: • e. g. chloroplast • e. g. mitochondrion

ORGANELLES IN CELLS Organelles f very small size – can only be observed under electron microscope f has specific functions f in cytoplasm

ORGANELLES IN CELLS Plant Cell • Chloroplast – Contain the green pigment chlorophyll • To trap light energy, to make food by photosynthesis

ORGANELLES IN CELLS Plant Cell • Chloroplast – Contain starch grains (products of photosynthesis)

ORGANELLES IN CELLS Plant Cell • Mitochondrion – Rod shape – For respiration which provides energy for all cell processes – Powerplant

ORGANELLES IN CELLS Plant Cell • Mitochondrion ( mitochondria ) – Active cells ( eg. sperms, liver cells) have more mitochondria

ORGANELLES IN CELLS • Vacuole Plant Cell – large central vacuole – Storage space for WATER, salts, proteins (enzymes), carbohydrates, and waste

ORGANELLES IN CELLS Plant Cell • Nucleus – Control the normal activities of the cell – Bounded by a nuclear membrane – Contains thread-like chromosomes

ORGANELLES IN CELLS Plant Cell • Nucleus – Each cell has fixed number of chromosomes • Chromosomes carry genes – genes control cell characteristics

ORGANELLES IN CELLS Plant Cell • Nucleolus – The dark in the nucleus • Makes RNA for ribosomes

Animal cell • No cell wall and chloroplast

ORGANELLES IN CELLS Animal Cell • Cytoskeleton – Helps cell maintain shape – Help move organelles around Made of PROTEINS: MICROFILAMENTS (Actin) & MICROTUBULES (Tubulin)

ORGANELLES IN CELLS Animal Cell • Centriole – Appear during cell division to guide chromosomes apart – Only in animal cells

ORGANELLES IN CELLS Animal Cell • Ribosome – Made of proteins and RNA – Protein factory for cells – remember that DNA tells the ribosome which proteins to make to have genetic traits show up

ORGANELLES IN CELLS Animal Cell • Endoplasmic Reticulum – Network of hollow tubes – Smooth ER – Rough ER – Like a highway for transporting

ORGANELLES IN CELLS Animal Cell • Endoplasmic Reticulum – Smooth ER – Makes membrane lipids (steroids) – Regulates calcium (muscle cells) – Destroys toxic substances (Liver)

ORGANELLES IN CELLS Animal Cell • Endoplasmic Reticulum – Rough ER – Makes membrane proteins and proteins for export out of cell

ORGANELLES IN CELLS Animal Cell • Golgi Apparatus – Pancake like membrane stacks – Modify, sort, & package molecules from ER for storage OR transport out of cell

ORGANELLES IN CELLS Animal Cell • Lysosome – Membrane bound sacs that contain PROTEINS called digestive enzymes – Digest food, unwanted molecules, old organelles, cells, bacteria, etc

ORGANELLES IN CELLS Animal Cell

ORGANELLES IN CELLS Similarities between plant cells and animal cells ¶Both have a cell membrane surrounding the cytoplasm ¶Both have a nucleus ¶Both contain mitochondria

ORGANELLES IN CELLS Differences between plant cells and animal cells Animal cells Plant cells Relatively smaller in size Relatively larger in size Irregular shape Regular shape No cell wall Cell wall present

ORGANELLES IN CELLS Differences between plant cells and animal cells Animal cells Plant cells Vacuole small or absent Large central vacuole Glycogen granules as food store Starch granules as food store Nucleus at the center Nucleus near cell wall

ORGANIZATION Levels of organization Cells are grouped together and work as a whole to perform special functions

ORGANIZATION Tissue A group of similar cells to perform a particular function Animals : epithelial tissue, muscular tissue Plants : vascular tissue, mesophyll

ORGANIZATION Organ Different tissues group together to carry out specialized functions Heart: consists of muscles, nervous tissue and blood vessels Leaf: consists of epidermis, mesophyll and vascular tissue

ORGANIZATION Level of Organization ³ cells (e. g. muscle cells, nerve cells) ³ tissues (e. g. muscle, epithelium) ³ organs (e. g. heart, lungs, stomach) ³ systems (e. g. circulatory system) ³ organisms (e. g. man)

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