Cellular Biology Sarah Bruemmer Cell Organelles Cellular Biology Sarah Bruemmer

Cell Theory The cell theory states: All organisms are composed of one or more cells. Cells are the basic unit of structure and function in organisms. All cells come only from other cells. Robert Hook: Looked through microscope and call the cork a “cell” - like a monk cell.

Cell Size

Cell Types Prokaryote Eukaryotes Small Cell (5<m) Larger cells (10> m) unicellular Uni or multicellular No nucleus or membrane bound organelles Nucleus and membrane bound organelles Circular DNA, without proteins Linear DNA, chromatin Small ribosomes (70S) Large ribosomes (80S) No Cytoskeleton Has cytoskeleton Motility by flagellum Various motility Binary Fission Mitosis or Meiosis Asexual Reproduction Asexual or sexual Reproduction Various metabolic pathways Similar metabolic pathways

Cell Membrane Both prokaryotic and eukaryotic cells have this cell membrane Holds the CYTOPLASM inside the cell and keeps unwanted things out of the cell Gives cells their shape and flexibility Helps to maintain HOMEOSTASIS by allowing certain substance to flow in and out of the cell = SELECTIVE PERMIABILITY

PHOSPHOLIPID BILAYER Hydrophilic head Fluid Mosaic Model: Phospholipids, cholesterol, and proteins that make up the cell membrane all flow like the surface of a wavy lake, moving and shifting.

Cell Wall Located outside the cell membrane Can be made of thick fibers of cellulose (plants), chitin (fungi), or peptodoglycan (some bacteria)--all of these are carbs Animal cells DO NOT have cell walls Provide rigid support

Nucleus Control Center of the cell Contains DNA used in cell replication Contains CHROMATIN (loose DNA) Enclosed by nuclear envelope with nuclear pores (small openings) Contains a NUCLEOLUS, which is made up of a mass of nucleotides used for making DNA and RNA

Nucleolus Part of the nucleus Makes ribosomes and sends them to the rough endoplasmic reticulum or cytoplasm

Cromatin Located in nucleus Bundles into CHROMOSOMES when cell is ready to divide (it packs before moving) Directs Protein Synthesis It contains the blueprints for the organism; this is the DNA

Cytoplasm Jelly like substance that fills the cell Mostly water, but contains a little bit of whatever has been eaten Incoming nutrients often dissolve directly into the cytoplasm

Endoplasmic Reticulum The endoplasmic reticulum (ER) is a system of membrane channels and little sacs that acts as a workspace for cellular reactions.

Smooth ER has no ribosomes and is where the cell makes phospholipids and packages proteins into vesicles (small storage sacs), among other functions. Rough ER is studded with ribosomes and is where proteins are made and processed. Ribosomes can be attached to ER or free. They are tiny organelles that make proteins. Ribosomes are made of RNA and protein

Glogi A flattened set of membranes called cisternae The “post office” of the cell Recieves protein from ER, processes and packages proteins for export via vesicles Makes lysosomes

Vesicle Eukaryotic Cells Membrane “bubbles”use to transport proteins “taxi cabs”

Lysosomes Small sacs full of hydrolytic (digestive) enzymes Break apart (digest) foreign substances Important to remove damaged or worn out cells.

Vacuoles Used for: storage of waste products, food and water, enzymes, etc. In plants, this is usually very large, called a central vacuole For shape

Mitochondria

The “powerhouse” of the cell Double membrane Endosymbiosis Theory plural = mitochondria The “powerhouse” of the cell Double membrane Endosymbiosis Theory Folded inner membrane (cristae) increase surface area for chemical reactions. Site of CELLULAR RESPIRATION: Releases energy from food molecules Creates ATP, an energy containing molecule that acts as a “battery” to power other cell reactions ATP is the energy currency of the cell

Chloroplast

Only found in green plant cells Cholophyll is a pigment which gives leaves their green color. Trap energy from sunlight to build food molecules and store for later use = site of photosynthesis Double membrane Endosymbiosis Theory Has a highly folded inner membrane (thylakoids) which increase surface area for chemical reactions.

Cytoskeleton The eukaryotic cytoskeleton is a network of microfilaments and microtubules that extends from the nucleus to the plasma (cell) membrane. Give cell its shape Help organelles move within the cell Examples: microtubules, microfilaments, intermediate fibers

Cilia and Flagella Cillia : Flagella: Tiny hair like structures surrounding the cell Made of microtubules “sweeping” motion Flagella: Whip-like tail attached at one end Made of micotubules “whip” motion

Centrioles Centrioles are short cylinders made of microtubules. Centrioles are only found in animal cells and are involved in building and taking apart microtubules during cell division and in the organization of cilia and flagella.