Cells (Chapter 7.1 & 7.2) 1

Introduction to Cells Cells are the basic units of organisms Cells can only be observed under microscope Basic types of cells: Animal Cell Plant Cell Bacterial Cell 2

Early cell biologists  Robert Hooke( ) England saw first cells under a microscope looked at cork  Anton van Leeuwenhoek( ) Netherlands Saw 1 st living cells 3

Number of Cells Organisms may be: Unicellular Multicellular 4

Cell Theory  All living things are made of cells  All cells come from pre-existing cells  Cells are the basic unit of structure and function 5

Prokaryotes  lack a nucleus & membrane-bound organelles  examples: bacteria  Eukaryotes  have a nucleus & membrane bound organelles  example: plants, animals, fungi & protists Cells May be Prokaryotic or Eukaryotic 6

Prokaryotes Has DNA but no nuclear membrane Cell membrane,cell wall,ribosomes 7

Eukaryotic Cell Contain 3 basic cell structures: nucleus cell membrane cytoplasm (with organelles) 8

Two Main Types of Eukaryotic Cells Plant Cell Animal Cell 9

Organelles Can only be observed under a microscope Have specific functions Found throughout cytoplasm 10

Controls the normal activities of the cell Bounded by a nuclear membrane Contains chromosomes (DNA) Nucleus 11

Each cell has fixed number of chromosomes Nucleus More on the Nucleus 12

Nucleolus  Cell may have 1 to 3 nucleoli  Inside nucleus  Makes ribosomes 13

Surrounds cytoplasm in both animal and plant cells Cell Membrane 14

Controls the movement of materials into and out of the cell Selectively permeable Cell Membrane 15

Jelly-like substance enclosed by cell membrane Cytoplasm Cytoplasm of a Cell 16

Contains organelles to carry out specific jobs More on Cytoplasm The actual fluid in the cell is called cytosol. 17

Ribosomes  Where proteins are made  Free or attached to Rough ER  Free ribosomes make proteins that will be used by that cell 18

Smooth & Rough Endoplasmic Reticulum Smooth ER lacks ribosomes & makes lipids(phospholipids & steroids) Rough ER has ribosomes makes proteins that are often secreted out of the cell 19

Golgi Bodies  Receives,modifies, & packages proteins  Transport vacuole with modified proteins pinch off the ends Transport vacuole 20

Rod shape Site of Cellular respiration Mitochondria Mitochondrion ( mitochondria ) 21

Active cells like muscles have more mitochondria Use organic compounds to produce energy In Animal Cells: Mitochondria 22

Lysosome  Contain digestive enzymes  Break down food and worn out cell parts for cells  Programmed for cell death 23

Cilia & Flagella  Used for movement  Cilia small hair-like extensions  Flagella one or two whip-like extensions 24

Cytoskeleton 25 Microtubules & Microfilaments: they help a cell maintain shape and move organelles around in cell.

Centrioles  Found in pairs  Help cells divide 26

Different kinds of animal cells white blood cell red blood cell cheek cells sperm nerve cell muscle cell Amoeba Paramecium 27

Dead layer Freely permeable (open spaces in wall) Cell wall Cell Wall 28

Cell Wall Made of cellulose Strong and rigid Gives shape to cell 29

Contain the green pigment chlorophyll Traps sunlight for photosynthesis Contain DNA Plant Cell Organelles Chloroplast 30

*Plants have a large central vacuole *Animal cells have small vacuoles Both use for storage Vacuoles 31

Different kinds of plant cells Onion Epidermal Cells Root Hair Cell root hair Guard Cells 32

Differences between plant cells and animal cells Animal cellsPlant cells Size Shape Cell Wall 33

Animal cellsPlant cells Food storage Nucleus position Vacuoles Differences between Plant Cells and Animal Cells 34