STRUCTURE & FUNCTION OF CELLS LECTURE #15 MS. DAY HONORS BIOLOGY

All living things are made of cells CELL THEORY All living things are made of cells Cells are the basic unit of structure and function in an organism Basic unit of life Cells come from the reproduction of existing cells Using cell division

Bacterial Cell (Prokaryote) CELL TYPES Three Basic types of cells include: Animal Cell (Eukaryote) Plant Cell (Eukaryote) Bacterial Cell (Prokaryote) **SMALLEST

Contain 4 basic cell structures: ALL CELLS… Contain 4 basic cell structures: Cell Membrane Cytoplasm Ribosomes DNA **not an organelle

PROKARYOTES: THE FIRST CELLS Simplest and smallest type of cell Ex: bacteria NO nucleus NO/FEW organelles 1 Single, circular chromosome (piece of DNA)

PROKARYOTES Nucleoid region (center) contains the DNA (NO nulceus) Surrounded by cell membrane & cell wall Contain ribosomes in their cytoplasm to make proteins Has cilia for reproduction and flagella for movement

THINK: “You carry a lot…of stuff” EUKARYOTES All eukaryotic cells HAVE: a Nucleus membrane-bound organelles These cell types (examples) includes: protists fungi plants animals More complex type of cells THINK: “You carry a lot…of stuff”

TWO MAIN TYPES OF EUKARYOTIC CELLS Animal Cell Plant Cell

ORGANELLES Very small Perform various functions for cell Mostly found in the cytoplasm May or may not be membrane- bound

BASIC ANIMAL CELL ORGANELLES Ribosome (attached) Nucleolus Ribosome (free) Nucleus Cell Membrane Nuclear envelope Mitochondrion Smooth endoplasmic reticulum Rough endoplasmic reticulum Centrioles Golgi apparatus

BASIC PLANT CELL ORGANELLES

CELL OR PLASMA MEMBRANE (aka: phospholipid bilayer) STRUCTURE Made of double layer (bilayer) of: phospholipids and proteins Surrounds outside of ALL cells FUNCTION (JOB) Controls what enters or leaves the cell Outside of cell Inside (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains

CELL WALL STRUCTURE Found in: plants Made of cellulose Fungi Made of chitin Bacteria Made of different sugar NOT IN ANIMAL CELLS!!! FUNCTION (JOB) Protect Maintain shape CELL WALL Cell wall

CYTOPLASM (aka: cytosol) STRUCTURE Jelly-like substance Mostly water aqueous solution FUNCTION (JOB) solution for chemical reactions to take place in Holds organelles cytoplasm

NUCLEUS STRUCTURE Contains the DNA Bounded by a nuclear envelope (membrane) with pores FUNCTION (JOB) Controls the normal activities of the cell Nuclear pores

NUCLEOLUS STRUCTURE Inside nucleus Cell may have 1 to 3 Disappears when cell divides FUNCTION (JOB) Makes ribosomes (ribosomal subunits)

MITOCHONDRION (PLURAL = MITOCHONDRIA) STRUCTURE Bean shape DOUBLE membrane Has its own DNA FUNCTION “Powerhouse” of cell Makes cellular energy (ATP) using CELLULAR RESPIRATION

CHLOROPLASTS STRUCTURE Bean shape DOUBLE membrane Has its own DNA FUNCTION (JOB) Found only in autotrophs Carries out photosynthesis

 RIBOSOMES STRUCTURE Made of PROTEINS and rRNA Think: “RIB”s are meat; meat is protein FUNCTION (JOB) Make proteins Hooks amino acids to make proteins Process called TRANSLATION 

RIBOSOMES (CON’T) Can be attached or bound to Rough ER Be free (unattached) in the cytoplasm

ROUGH ENDOPLASMIC RETICULUM (RER) STRUCTURE Has ribosomes on its surface FUNCTION (JOB) Helps to make proteins for export out of cell

SMOOTH ENDOPLASMIC RETICULUM (SER) STRUCTURE NO ribosomes on its surface Usually attached to RER Hollow tubes FUNCTION (JOB) Makes lipids Destroys toxins (liver)

GOLGI APPARATUS (BODIES) STRUCTURE Stacks of flat sacs (NOT CONNECTED!) Looks like pancakes with syrup drips “Pankcakes” NOT connected FUNCTION (JOB) Modify Sort Package Molecules for storage OR transport in vesicles Transport vesicle “syrup bubble”

CYTOSKELETON STRUCTURE FUNCTION (JOB) Made of proteins Microfilaments are threadlike Microtubules are tube- like FUNCTION (JOB) Help maintain cell shape Help move things around cell

CENTRIOLES STRUCTURE FUNCTION (JOB) In animal cells ONLY Inside CENTROSOMES Paired structures near nucleus (“t” shape”) Made of microtubules FUNCTION (JOB) Appear during cell division Help pull chromosomes apart

CENTRIOLES & THE MITOTIC SPINDLE **Made of MICROTUBULES (Tubulin)

CILIA & FLAGELLA STRUCTURE Made of microtubules Shorter more numerous Longer fewer (usually 1-3)

Moves fluids, gases or small particles across cell surface CILIA & FLAGELLA FUNCTION (JOB) of Flagella Moves WHOLE cells FUNCTION (JOB) of Cilia Moves fluids, gases or small particles across cell surface

LYSOSOMES STRUCTURE FUNCTION (JOB) They have a low pH (acidic!) Contain digestive enzymes FUNCTION (JOB) Break down/recycle food, bacteria & old cell parts Think= “Lysol” cleaner (a) Phagocytosis: lysosome digesting food 1 µm Lysosome contains active hydrolytic enzymes Food vacuole fuses with lysosome Hydrolytic enzymes digest food particles Digestion Food vacuole Plasma membrane Lysosome Digestive Nucleus

VACUOLES STRUCTURE Sacks for storage Small or absent in animal cells Plant cells have a large Central Vacuole No vacuoles in bacterial cells Storage for water, food, wastes, enzymes, etc…

NOW…LET’S PRACTICE 