BASIC STRUCTURE OF A CELL MS. GAYNOR HONORS GENETICS

CELL THEORY 1. All living things are made of cells 2. Cells are the basic unit of structure and function in an organism Basic unit of life 3. Cells come from the reproduction of existing cells Using cell division

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

NUMBER OF CELLS Although ALL living things are made of cells, organisms may be: Unicellular – composed of one cell Multicellular - composed of many cells that may organize into tissues, etc. I look BIG here, I’m very small!

MULTICELLULAR ORGANISMS Cells in multicellular organisms often specialize (take on different shapes & functions)

CELL SPECIALIZATION Cells in a multi- cellular organism become specialized by turning different genes on and off This is known as DIFFERENTIATION

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 (made of peptidoglycan) Contain ribosomes in their cytoplasm to make proteins Has cilia for reproduction and flagella for movement

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

TWO MAIN TYPES OF EUKARYOTIC CELLS Plant Cell Animal Cell

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

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 of cell (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 NO IN ANIMAL CELLS!!! FUNCTION (JOB) Protect Maintain shape 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

20 NUCLEAR ENVELOPE Double membrane surrounding nucleus Also called nuclear membrane Contains nuclear pores for materials to enter & leave nucleus Connected to the rough ER Nuclear pores

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

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

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 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 amino acids to make proteins Process called TRANSLATION 

RIBOSOMES (CON’T) Can be attached to Rough ER (proteins made exit cell) 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

GOLGI APPARATUS 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 CIS TRANS

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

NOW…LET’S PRACTICE