The Cell

How big is a cell? Rearrange these items in order from LARGEST to SMALLEST: Mitochondrion E coli bacterium grain of rice red blood cell Glucose Sperm carbon atom water molecule skin cell

Cell Size How big is a cell? http://learn.genetics.utah.edu/content/begin/cells/scale/

Biological Levels of Organization • Atom • Molecule • Macromolecule • Organelle • Cell • Tissue • Organ • Organ system • Organism • Population • Community • Ecosystem • Biome • Biosphere Small BIG!!

• Remove wastes (CO2, etc.) • Reproduce Needs of a Cell • Get food • Get oxygen • Remove wastes (CO2, etc.) • Reproduce – Limits to cell size...when too big, split in two • Maintain homeostasis.

Two Basic Cell Types Prokaryote Lacks internal compartments. No true nucleus. Most are single-celled (unicellular) organisms. Examples: bacteria

Two basic cell types Eukaryote Has several internal structures (organelles). True nucleus. Either unicellular or multi-cellular. • unicellular example: yeast • multi-cellular examples: plants and animals

Organelles Small, membrane-bound structures in a cell Specialized Like organs in the human body

Organelles Cell Membrane Separates the interior of the cell from the exterior (outside) environment. Selectively permeable: Allows certain materials to pass in and out of the cell. Function: Protects the cell from its surroundings Found in plants and animal cells

ORganelles Cell Wall Surrounds the plasma membrane Found in plant, bacteria and fungi cells. NOT ANIMAL CELLS Function: Provides rigid layer, does not allow over-expansion when water enters. Have students chat in table groups to come up with a group role for these two.

ORganelles Nucleus Function: Regulates cell function-acts as a control center Surrounded by a double-layered membrane (nuclear envelope) with large pores that allow materials to pass in and out of the nucleus. Contains genetic material, chromatin – long tangles of DNA and chromosomes: coils of DNA.

ORGANELLES Chromosomes and Chromatin Structures made of DNA (Nucleic Acid) FUNCTION: holds the instructions for how to make the cell’s proteins

organelles Nucleolus Found in the nucleus and responsible for ribosome production Ribosomes are the sites of protein production.

organelles Cytoplasm The jelly-like material that surrounds the organelles. Function: support

Organelles Ribosome FUNCTION: synthesize (makes) protein

organelles Endoplasmic reticulum Folded membrane that acts as a network for transportation. Smooth E.R. contains enzymes for lipid synthesis. Rough E.R. is studded with ribosomes for protein synthesis. Function: cell’s delivery system.

Organelles Golgi apparatus (or Golgi body) A series of flattened sacs where newly made lipids and proteins from the E.R. are repackaged and shipped to the plasma membrane. Function: packaging & shipping

Organelles Vacuoles A sac of fluid surrounded by a membrane Function: used to store food, fluid, or waste products. Plants-1 large vacuole Animals-few small or no vacuole

Organelles Lysosomes Contain a digestive enzyme. Fuse with vacuoles to digest contents. Function: breakdown food, waste, worn out organelles, viruses and bacteria. Also known as “suicide sacs” because they can also destroy the whole cell.

Organelles Mitochondria Produce the energy for the cell. Function: powerhouse of the cell. Has a highly folded inner membrane called cristae

Organelles Chloroplasts Found in plant cells and some protists. Transforms light energy into chemical energy which is stored in food molecules. Function: photosynthesis Contain chlorophyll – a green pigment that traps light energy and gives plants their green color. Part of a group of plant organelles called Plastids

Microtubules – hollow filaments of protein. Organelles Cytoskeleton A network of thin, fibrous materials called Microtubules and Microfilaments that act as a scaffold Function: support the organelles Microtubules – hollow filaments of protein. Microfilaments – solid filaments of protein.

Organelles Centrioles Star-like structures made of microtubules. play a role in the splitting of the cell into two cells. Function: cell division found in animal and fungi cells.

organelles Cilia Short, numerous, hair-like projections from the plasma membrane. Move with a coordinated beating action.

Organelles Flagella Longer, less numerous projections from the plasma membrane. Move with a whip-like action.

when cells don’t work properly Cystic Fibrosis-(hereditary) A defective gene makes a protein that doesn’t work to control the movement of salt and water in and out of your body's cells. Causes thick, sticky mucus to build up in the lungs, digestive tract, and other areas of the body. It is one of the most common chronic lung diseases in children and young adults.

when cells don’t work properly Tay-Sachs Disease-(hereditary) Tay-Sachs disease occurs when the body lacks a protein that helps break down a chemical found in nerve tissue. Without this protein, the chemical builds up in cells, especially nerve cells in the brain.

when cells don’t work properly Sickle Cell Anemia-(hereditary) red blood cells form an abnormal sickle or crescent shape. Red blood cells carry oxygen to the body and are normally shaped like a disc. The fragile, sickle-shaped cells deliver less oxygen to the body's tissues.