Organelles

Eukaryotic Cells The Inside Story

2 Types of Cells Prokaryotic Eukaryotic Cells Cells • No nucleus • Nucleus • No membrane- DNA • Membrane - Cells covered covered organelles organelles • Linear DNA • Circular DNA • All other cells • Bacteria

Which is which?

Cells come from.. 1 of the 3 parts of the Cell Theory states  that All cells come from pre-existing cells  So just as large multicellular organisms  like humans, dogs, and trees reproduce, your cells do as well

So What is Inside a Cell? It turns out that there is a lot more inside a cell  than Robert Hooke or Anton von Leeuwenhoek probably would have guessed. Everything, from the structures covering the  cells to the structures inside, perform tasks to help keep the cells alive. These structures are called organelles. 

Holding It All Together All cells have outer coverings that separate  what’s inside the cell from what is outside. Membrane Cell Covers all cells, both eukaryotic and prokaryotic   Duties include keeping cytoplasm inside  Allow nutrients in and waste products out  Also interacts with things outside the cell

Holding It All Together Wall Cell Only found in plant and bacteria(prokaryotic) cells  Cell wall in plants is made of cellulose  Provides strength and support to the cell membrane  The strength of billions of cell walls in plants  enables a tree to stand tall and its limbs to defy gravity

The Cell’s Library Nucleus Largest and most visible organelle   Covered by a membrane  Control center of cell  Stores the DNA Nucleolus Dark spot inside the nucleus   Stores the materials that will be used later to make ribosomes in the cytoplasm

Protein Factories Ribosomes Smallest but most abundant organelles  Their job is to hook together amino acids to make proteins  Found in both eukaryotic and prokaryotic cells  Not covered by a membrane  All cells have ribosomes because all cells need protein  to live.

The Cell’s Delivery System Reticulum Endoplasmic Internal delivery system of a cell   Is divided into Smooth and Rough ER based on appearance and function  Rough ER Ribosomes are attached making it look pebbled   Specializes in protein synthesis  Connected to nuclear membrane  Proteins synthesized by ribosomes collect in the ER for transport throughout the cell

Difference Between Rough and Smooth ER  Smooth ER Does not have ribosomes attached  Has different functions depending on the cell type  Can be responsible for lipid and hormone synthesis  Breaks down drugs and certain other chemicals that  could damage the cell

The Cell’s Power Plants Mitochondria  Convert the chemical energy stored in food into ATP which is the molecular fuel that cells use to do work  Inner membrane of mitochondria that has many folds is where most of the ATP is made.  The reason you breathe air is so that mitochondria have the oxygen they need to make ATP Highly active cells, like those in the liver and  heart, may have thousands of mitochondria while other cells may have only a few.

The Cell’s Power Plants Chloroplasts Additional kind of energy-converting organelle  found in plants and algae  Contain flattened, membrane-covered sacs that look like stacks of coins which contain chlorophyll  Chlorophyll is what makes plants green and also traps the energy in sunlight which plants use to make sugar  The sugar that is produced is used by

The Cell’s Packaging Center Apparatus Golgi Looks like ER but is located closer to the cell  membrane  Receives and modifies lipids and proteins sent from the ER  Final products are then enclosed in a piece of the Golgi’s membrane that pinches off to form small compartment  Compartment transports contents to other parts of cell or outside the cell

The Cell’s Storage Centers Vacuoles Very large in plant cells, much smaller in animal  cells  Store water and other liquids  If full of water they help support the cell Store the liquids that make roses red and  violets blue  Contain the juices you associate with oranges and other fruits

The Cell’s Storage Centers Vesicles Some form when part of the membrane  pinches off the ER or Golgi Others are formed when part of the cell  membrane surrounds an object outside the cell

Packages of Destruction Lysosomes Special vesicles in animal cells that contain  enzymes that digest food particles and wastes  Destroy worn-out or damaged organelles  Get rid of waste materials and protect cell from foreign invaders  If lysosome membrane breaks, the enzymes spill out into the cytoplasm which

Plant or Animal?

Homework You are going to create a drawing of a  eukaryotic cell. However, instead of making it a realistic  cell, your cell should be made of drawings of objects that represent the organelle’s job. For example, the Golgi Apparatus, which  transports materials, could be a bus or a car.

Organelles

by mlong24 on Apr 17, 2009

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