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Cell Types and Organelles
The cell is like your house
Cells are like houses. Form= Function An organelle’s shape has a lot to do with what job it does, much like the Lock and Key model in enzymes. This is like the rooms in a house. Each has a specific purpose. Just like not all houses have the exact same rooms, not all cells have the same organelles.
Prokaryotes vs. Eukaryotes Use the Venn Diagram below to fill-in the house diagram in your notes. prokaryote No nucleus No membrane. Bound organelles both eukaryote DNA nucleus Cell membrane organelles Ribosomes Multi- or single-celled All single-celled cytoplasm
3. 2 Cell Organelles
Cells have an internal structure • Eukaryotic cells have a cytoskeleton, a framework of proteins that is constantly changing to meet the needs of the cell.
• The cytoskeleton helps the cell maintain its shape and moves organelles around
When cytoskeleton goes bad… Amyotrophic lateral sclerosis, or ALS, or Lou Gehrig’s disease occurs when there are defective cytoskeleton in the nerve cells in the brain and spinal cord.
Cytoplasm • A jelly-like substance that also helps the cell maintain shape. • Contains the organelles in eukaryotic cells • Composed mostly of water • Many chemical reactions occur in the cytoplasm where water acts as a solvent.
Organelles involves in proteinmaking • Proteins are important molecules in the body that are made up of amino acids.
NUCLEUS Largest organelle in eukaryotic cells
Organelles involved in making and processing proteins Contains the cell’s genetic information (DNA)
NUCLEUS Surrounded by the NUCLEAR ENVELOPE (also called NUCLEAR MEMBRANE)
Organelles involved in making and processing proteins NUCLEUS DNA is scrunched up as CHROMOSOMES in dividing cells DNA is spread out as CHROMATIN in non-dividing cells
The DNA in the nucleus must be protected, yet certain materials need to get in and out of the nucleus.
The special structure of the nucleus protects it and allows it to perform its functions.
The nuclear envelope is pierced with holes called nuclear pores that allow large molecules to pass in and out of the nucleus.
Organelles involved in making and processing proteins • The nucleus contains the nucleolus- a dense region where organelles called ribosomes are made.
Electron microscope Image of a cell
Let’s Review cytoskeleton nucleus Nuclear envelope Cytoplasm Nuclear pore Nucleolus
Ribosomes link amino acids together to make proteins.
Organelles involved in making proteins Ribosomes • Some ribosomes are bound to the ER. • Some are suspended in the cytoplasm.
Organelles involved in making proteins Endoplasmic Reticulum A network of thin folded membranes.
Organelles involved in making proteins Endoplasmic Reticulum
Creases and folds allow the ER to pack tightly into the cell.
Organelles involved in making proteins Endoplasmic Reticulum • There are two kinds of ER – Rough ER – Smooth ER
ROUGH ENDOPLASMIC RETICULUM (Rough ER) Rough ER is where proteins are produced, processed and distributed within the cell.
Rough ER are studded with organelles called ribosomes. Rough ER
ROUGH ENDOPLASMIC RETICULUM (ER) • Proteins are made on ribosomes and inserted into Rough ER to be modified and transported to another organelle
Rough endoplasmic reticulum (with ribosomes)
Smooth ER The smooth ER does not have ribosomes. It is the site where lipids are made.
Figure 7 -5 Plant and Animal Cells Animal Cell Section 7 -2 Cytoplasm Nucleolus Cell Membrane Nucleus Rough Endoplasmic Reticulum Go to Section: Smooth Endoplasmic Reticulum
Organelles involved in making proteins: Golgi Apparatus Their function is to modify, sort, & package proteins received from the ER for storage or transport out of cell
GOLGI APPARATUS (BODY) • Closely layered stacks of flattened membranes.
Animation from: http: //www. franklincollege. edu/bioweb/A&Pfiles/week 04. html See a Golgi movie
ER and Gogi Apparatus
Figure 7 -5 Plant and Animal Cells Animal Cell Section 7 -2 Cytoplasm Nucleolus Nucleus Rough Endoplasmic Reticulum Golgi apparatus Go to Section: Ribosomes Cell Membrane Smooth Endoplasmic Reticulum
Other organelles Mitochondria The mitochondria are beanshaped organelles that supply energy to the cell
MITOCHONDRIA are Surrounded by a DOUBLE membrane Folded inner membrane increases surface area for more chemical reactions
It is within these inner folds that chemical reactions occur that converts food molecules into usable energy.
The folds inside of the mitochondria are called cristae. Nickname “Powerhouse of the cell” The chemical reaction is called cellular respiration.
Animal Cell Cytoplasm Nucleolus Nucleus Ribosomes Cell Membrane Mitochondria Rough Endoplasmic Reticulum Golgi Bodies Smooth Endoplasmic Reticulum
Vesicles • Vesicles are small membrane-bound sacs that keep reactants from various chemical reactions separated from the rest of the cell. • They also transport these materials from place to place within the cell.
Vesicles are temporary and are formed and recycled by the cell as needed.
Vacuole A vacuole is a fluid-filled sac used for the storage of materials needed by the cell.
Vacuole • The vacuole stores materials such as – Water – Food molecules – Ions – Enzymes
Figure 7 -5 Plant and Animal Cells Section 7 -2 Vacuole Go to Section: Plant Cell
Lysosomes Membrane bound sacs that contain PROTEINS called digestive enzymes
Functions of Lysosomes • Lysosomes defend a cell from invading bacteria. • They break down damaged or worn-out cell parts. • Contain digestive enzymes. It is important that they are surrounded by a membrane.
“PROGRAMMED CELL DEATH” APOPTOSIS = ___________ Lysosomes digest unwanted cells
Lysosome problem… Tay Sach’s Disease • People with Tay Sach’s disease lack a lipid dissolving enzyme in their vesicles. • Causes lipids to accumulate in the brain.
Centrioles • Centrioles are cylinder-shaped organelles • Involved in animal cell division • Not found in plant cells
CENTRIOLES They appear during cell division to guide chromosomes apart
• Animal cells contain many small vacuoles. • Plants usually have one large, central vacuole.
FLAGELLA & CILIA help cells move
WHAT’S THE DIFFERENCE? CILIA • Many • short FLAGELLA • Few • Long
PLANT CELLS WHAT’S SPECIAL ABOUT THEM? • • Cell wall HUGE vacuoles Chloroplasts No centrioles
The central vacuole in a plant cell is filled with water which helps to support the plant. If there is not enough water, the plant will wilt.
Some organisms have a contractile vacuole to pump excess water out
• Chloroplasts are organelles that use sunlight to produce sugars.
• They are the organelles in which photosynthesis occurs.
Chloroplasts are only found in plant cells and in green algae.
CELL WALL A cell wall is a rigid layer that protects, supports and shapes the cell.
Cell Walls • Cell walls are found mostly in plant cells.
Cell walls are also found in some algae cells and…
…in most bacteria and…
…in fungal cells a yeast cell reproducing by budding Candida albicans
• Plants cell walls are composed of the carbohydrate cellulose
Tree bark is mostly made up of dead cell walls
Plant Cell Review Cytoplasm Vacuole Smooth ER Ribosomes Chloroplasts Cell Membrane Cell Wall Nucleolus Golgi Bodies Nucleus Mitochondria Rough ER
WHICH IS BIGGER? Plant cell Animal cell bacteria _________ > ___________
No membrane bound organelles Organelles with membranes BACTERIA are PROKARYOTES PLANTS & ANIMALS are EUKARYOTES
USE WORDS FROM THE WORD BANKS TO COMPLETE THE VENN DIAGRAM COMPARISON
Endoplasmic Reticulum • Connected to nuclear membrane • Highway of the cell • Rough studded with ribosomes; it makes proteins • Smooth no ribosomes; it makes lipids
Golgi Apparatus • Looks like a stack of plates • Stores, modifies and packages proteins • Molecules transported to and from the Golgi by means of vesicles
Name the organelles that are circled mitochondria
Centriole • Aids in cell division • Usually found only in animal cells • Made of microtubules Where else have we talked about microtubules?
Ribosome • Site of protein synthesis • Found attached to rough ER or floating free in cytosol • Produced in a part of the nucleus called the nucleolus
Cytoskeleton • Acts as skeleton and muscle • Provides shape and structure • Helps move organelles around the cell • Made of three types of filaments
Cell Membrane • Boundary of the cell • Made of a phospholipid bilayer
Mitochondria • “Powerhouse of the cell” • Cellular respiration occurs here to release energy for the cell to use • Bound by a double membrane
Water, food, waste, enzymes • What type of substances might be found in part C?
Lysosomes • Garbage disposal of the cell • Contain digestive enzymes that break down wastes
Cell Wall • Found in plant and bacterial cells • Rigid, protective barrier • Located outside of the cell membrane • Made of cellulose (fiber)
Nucleus • Control center of the cell • Contains DNA • Surrounded by a double membrane • Usually the easiest organelle to see under a microscope • Usually one per cell
Name part A chloroplast
Chloroplast • Found only in plant cells • Contains the green pigment chlorophyll • Site of food (glucose) production