BASIC STRUCTURE OF A CELL MS. DAY HONORS GENETICS

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

PROKARYOTES…in detail Nucleoid region (center of cytosol) contains the DNA (NO nucleus) Surrounded by cell membrane & cell wall (made of peptidoglycan) Contain ribosomes in their cytoplasm to make proteins Has cilia for reproduction and flagella for movement PROKARYOTES…in detail

TWO MAIN TYPES OF TYPICAL EUKARYOTIC CELLS Animal Cell Plant Cell

CELL ORGANELLES MS. DAY HONORS GENETICS

ORGANELLES Very small Perform various functions for cell 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 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 peptidoglycan NOT IN ANIMAL CELLS!!! FUNCTION (JOB) Protect Maintain shape CELL WALL Cell wall

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

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

NUCLEAR ENVELOPE (membrane) STRUCTURE Double membrane  surrounds nucleus Contains nuclear pores (holes) Connected to the rough ER FUNCTION (JOB) pores (holes) allow materials to enter & leave nucleus Nuclear pores

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

CYTOSKELETON STRUCTURE FUNCTION (JOB) Made of proteins Microfilaments are threadlike Microtubules are tube-like FUNCTION (JOB) Network of fibers that help cell maintain cell shape Also help move organelles around

Table 6.1

MITOCHONDRION (PLURAL = MITOCHONDRIA) STRUCTURE Bean shape DOUBLE membrane Has its own DNA and ribosomes FUNCTION (JOB) “Powerhouse” of cell Makes cellular energy (ATP) Site of CELLULAR RESPIRATION (burning glucose)

INTERESTING FACT --- Mitochondria Come from cytoplasm in the EGG cell during fertilization Therefore … You inherit your mitochondria from your mother!

CHLOROPLASTS STRUCTURE Bean shape DOUBLE membrane Has its own DNA and ribosomes FUNCTION (JOB) Carries out photosynthesis NOT in animal OR fungi cells In plants and some protists

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

RIBOSOMES (CON’T) Can be attached to Rough ER (makes proteins that exit cell) **Think: “a”ttached = “a”way OR Be free (unattached) in the cytoplasm (proteins made stay INSIDE cell)

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 Has NO ribosomes on its surface Usually attached to RER FUNCTION (JOB) Makes lipids (membranes) Regulates calcium (muscles) Destroys toxins (Liver)

GOLGI APPARATUS (Bodies) STRUCTURE Hollow flattened sacs Looks like a stack of pancakes with syrup dripping off FUNCTION (JOB) Receives cell products (like proteins) from Rough ER Modifies (changes) and packages proteins for shipment OUT of the cell Proteins are packages into vesicles (the “syrup drips”) Transport vesicle

ENDOMEMBRANE SYSTEM Includes nuclear membrane connected to ER connected to cell membrane (transport)

CENTRIOLES STRUCTURE FUNCTION (JOB) Found only in animal cells inside CENTROSOMES Paired structures near nucleus (“t” shape”) Made of microtubules FUNCTION (JOB) Appear during cell division Help to pull chromosome pairs apart to opposite ends of the cell

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

LYSOSOMES STRUCTURE FUNCTION (JOB) Have a low pH (acidic) Contain digestive enzymes FUNCTION (JOB) Break down food, bacteria & old cell parts Help carry out cell death (APOPTOSIS) Think= “Lysol” cleaner Usually only in animal cells (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

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

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

NOW…LET’S PRACTICE 