Chapter 4 - Cell Structure and Function
The printed out notes are more detailed than these slides, you are expected to read the chapter and your notes - anything is fair game on the test, but the cell chapter is largely review.
Lab: microscopes and membranes Thurs: 10/9
A. The Cell Theory 1. Every living organism is made of one or more cells. 2. The cell is the basic unit of structure and function. It is the smallest unit that can perform life functions. 3. All cells arise from preexisting cells.
*Why is the Cell Theory called a Theory and not a Fact?
Cells need a large surface area to volume ratio
If there a person was at the very center of each house and accidently started a fire, the person in which house would have a better chance of escaping?
Figure 4.3
Early Contributions Hooke Leeuwenhoek Schleiden Schwann Virchow
http://htwins.net/scale2/
B. ALL CELLS HAVE: 1. Cell Membrane a) Phospholipid Bilayer (double layer) b) Proteins c) Carbohydrates
2. Genetic Material 3. Cytoplasm (cytosol)
ORGANELLES float within cytoplasm and perform specific functions
Prokaryote Cells
Figure 4.4a
Eukaryotes
Endosymbiosis : All organelles seem to share many properties with bacteria. Lynn Margulis proposed:
endosymbiosis hypothesis: that ancient colonization of large bacteria (became the eukaryotic cell) engulfed smaller bacteria (became the mitochondria, chloroplast, etc.) Symbiosis = "living together".
*Mitochondria & Chloroplasts have their own DNA Animation at Microbiological Concepts https://www.youtube.com/watch?v=3ESXvLHceDc
Endosymbiosis Theory that ancient colonization of large bacteria (became the eukaryotic cell) engulfed smaller bacteria (became the mitochondria, chloroplast, etc.)
http://www.youtube.com/watch?v=-FQmAnmLZtE
In your notes:
Create a diagram comparing prokaryotic and eukaryotic cells. Include examples of each and anything you can remember
When done, use ch 4 to label the pictures on your notes outline handout pg 65 and 68
Prokaryote
No Organelles Simple Mostly single cells Archaea and bacteria
both Cells DNA
Eukaryote
Membrane Bound Organelles
Cytoplasm
Nucleus
Plasma Membrane
Complex Specific in function
Ribosome Cell wall
Multicellular Plants, Animals, fungi
Quick Recap....... 1. What are the two main types of cells? 2. Which one is larger? 3. Which one does not have a membrane bound nucleus? 4. What are the three main parts of the cell (that all cells have)? 5. What are the 3 components of the cell theory? 6. What theory best explains how eukaryotes evolved? Label the pictures on the top of your notes outline: use 65, 68-69 to help
Prokaryotic or Eukaryotic? 1 2 1. Has membrane bound organelles 2. Includes plant and animals cells 3. Bacteria P 4.
E 5.
P 6. Has no organelles
P
E E
cell biology is a huge area, and is divided into many branches that biologists specialize in... 1) Oncology 2) Microbiology 3) Genetics 4) Paleobiology 5) Pathology ............to name a few Here's an older video that compares prokaryotes and eukaryotes and discusses how cells evolved, film by the Phoenix Learning Group (17 minutes) And a shorter video on the main parts of The Cell
The Parts of the Cell
Cell Diagram Directions: 1. You will get a picture of a animal or plant cell, label the cell. 2. label as many parts as you can remember 3. Then look in your book to label the rest 4. Write a 2-5 word description of the function of each part
II. Nucleus: • Nucleoplasm: semifluid matrix • Chromatin: uncoiled, fluid DNA and proteins • Chromosomes: coiled, rodlike DNA structures • Gene: unit of heredity located on DNA
• Nucleolus: dark region of chromatin where rRNA joins with proteins to form ribosomal subunits (parts to make ribosomes) • nuclear envelope contains nuclear pores for some things to enter and exit
III. Endomembrane System:
Includes: a. Nuclear envelope b. Membrane of the ER c. Golgi apparatus d. Several types of lysosomes
I am a reticulated python. Ask me what I have to do with the endoplasmic reticulum.
A. Nuclear Envelope/ Membrane: RNA leaves nucleus to instruct production of proteins
B. Endoplasmic Reticulum (endoplasm= "within cytoplasm", reticulum= "little net" --divides cell into compartments --channels molecules through the cell's interior, like a little highway, make vesicles
Figure 4.10a
Rough ER --has ribosomes --functions in protein synthesis -- ER transports newly assembled proteins to the Golgi Apparatus Smooth ER --no ribosomes --mostly contains enzymes that act in lipid synthesis (such as hormones like estrogen and testosterone) Vary depending on location
C. Golgi Apparatus: Delivery System
-flattened stacks of membranes -functions in collection, modifying, packaging and distribution of molecules made in the cell and used elsewhere
-unprocessed proteins enter the front end (cis) near the ER, and are exported near the cell membrane, at the back end (trans) --the folded stacks are called cisternae
Jobs of the Golgi Apparatus (aka Golgi Complex) 1. separates proteins according to their destinations 2. modifies proteins (adds sugar and makes glycoproteins) 3. packages materials into vesicles which are exported outside the cell - secretion
Lysosomes - Intracellular Digestion Centers --contain high levels of degrading enzymes (to "lyse" means to dissolve) --recycle old and worn out cell parts - apoptosis "suicide sac” -digest other particles taken in by phagocytosis --this "food" is stored in food vacuoles, the lysosomes fuse with the vacuoles and release digestive enzymes
Lysosomes - Intracellular Digestion Centers
TAY-SACHS disease – What do lysosomes have to do with this deadly disease? Article and Video on Tay Sachs http://6abc.com/archive/9036458/ https://www.youtube.com/watch?v=RzEpkBU-ITA
Tay-Sachs disease is caused by the absence or significantly reduced level of a enzyme called beta-hexosaminidase (Hex-A). Normally, Hex A is a digestive enzyme that is part of the lysosome. Without the correct amount of the Hex-A enzyme, a fatty substance or lipid called GM2 ganglioside accumulates abnormally in cells, especially in the nerve cells of the brain.
Ribosomes - Sites of Protein Synthesis -each is composed of two subunits, one large and one small -mRNA is "read" by the ribosomes and amino acids are assembled into proteins -ribosomes are manufactured by the nucleolus, assembles by ER --polyribosomes – strings of ribosomes in the cytoplasm that work to make a protein
Free vs Bound Ribosome Free ribosomes: produce proteins that are used by the cell. - ex: for metabolism of food. Bound ribosomes: produce proteins that are transported out of the cell. - ex: for a specific function, such as digestive enzymes and polypeptide hormones.
Mitochondria
--contains its own DNA, support for Endosymbiosis Theory • mitochondria divide before cell division, they are not synthesized like other cell parts --function: store energy for cell use. Energy is stored in the form of ATP adenosine triphosphate
-2 membranes, one smooth outer membrane, and an inner membrane folded into layers called cristae --Cristae has two compartments: the matrix and the intermembrane space
What happens if your mitochondria don’t work? Mitochondrial Disease Video Why is mitochondrial disease so devastating to children? Consider the mitochondria have their own DNA separate from the parental DNA. How could you cure this disease?
https://www.youtube.com/watch?v=6_ylLEhRG30
QOD: Cells 1. What parts of the cell are involved with protein production and what role does each part play? 2. Compare and contrast plant and animal cells use a graphic organizer: (venn, tree map, etc)
• Plant Cell • Animal cell • Eukaryote • Plasma Membrane • Nucleus • Ribosome • ER • Mitochondria • Chloroplast
• Cell wall • Cytoplasm • Golgi Apparatus • Vacuole • Centrioles • Fern Cells • Muscle Cells • Human Cells
Focus on Plant Cells
Chloroplasts - Where Photosynthesis Takes Place Plants only
--has its own DNA, like mitochondrion --functions: to convert light energy to carbohydrates --carbohydrates then broken down in mitochondria to produce ATP
Parts of chloroplast --thylakoids are the individual disk shaped compartments -- Grana: stack of thylakoids --stroma is the fluid surrounded the thylakoids
*Chloroplasts are a type of plastid Chromoplasts – red, yellow and orange pigment Leucoplasts – colorless (potatoes)
Cytoskeleton- support system a. Microfilaments (now called actin filament) – occur in bundles, form tracks within the cell for the movement of organelles, used to form pseudopods (ameba) b. Intermediate filaments - support membrane, cell to cell junctions c. Microtubules - (little pipe) radiate from the centrosome - form the spindle during cell division
Centrioles – used during cell division to move and separate chromosomes, only found in animal cell
Cytoskeleton How do cells maintain their shape? How do they move? - pseudopod - cilia - flagella
Pseudopod – extensions of the cell that allow for movement (ameba), depend on actin filaments Cilia (hair) & Flagella (whip) --function in movement -- 9 + 2 Arrangement of microtubules http://www.youtube.com/ watch?v=7pR7TNzJ_pA
Hey....remember enzymes? The Peroxisome Found in plant and animal cells, this organelle plays a critical role in normal cell functioning. In human cells, peroxisomes house
some
sixty enzymes, involved in metabolic processes such as bile acid, cholesterol, and plasmalogen biosynthesis, as well as ß-oxidation peroxisome produces hydrogen peroxide as a by-product of its normal function. -To neutralize this potentially toxic compound, a peroxisome imports the hydrogen peroxidemetabolizing enzyme catalase, from the cytosol of the cell. Catalase converts hydrogen peroxide to water and oxygen
Vacuole
-- mainly storage or specific functions (contractile vacuole, fat vacuole) -- Plant cells have a CENTRAL VACUOLE - used for storage and help to maintain hydrostatic pressure
Cell Diagram Directions: 1. You will get a picture of a animal or plant cell, label the cell. 2. label as many parts as you can remember 3. Then look in your book to label the rest 4. Write a 2-5 word description of the function of each part
QOD: Cells 1. What parts of the cell are involved with protein production and what role does each part play? 2. Compare and contrast plant and animal cells use a graphic organizer: (venn, tree map, etc)
• Plant Cell • Animal cell • Eukaryote • Plasma Membrane • Nucleus • Ribosome • ER • Mitochondria • Chloroplast
• Cell wall • Cytoplasm • Golgi Apparatus • Vacuole • Centrioles • Fern Cells • Muscle Cells • Human Cells
Plant
Animal
Tree Map
Double Bubble (like a venn diagram)
Cell wall Eukaryote vacuole
centrioles
Nucleus Mitochondria
Plant Cell Chloroplast Fern
Cytoplasm
Animal Cell
Muscle cells
Plasma Membrane Ribosome ER lysosome Golgi apparatus
humans
Eukaryote Plant Cell
Animal Cell
Central vacuole
centrioles Nucleus
Cell wall Chloroplast Fern
Mitochondria
Muscle cells
Cytoplasm
Plasma Membrane Ribosome ER lysosome Golgi apparatus
humans
What parts of the cell are involved with protein production and what role does each part play?
Most of the Endomembrane: • Nucleolus • Rough ER • Golgi • Vesicles • Free Ribosome
Mini Quiz 1. What part of the cell produces vesicles for export? 2. What part of the cell makes proteins? 3. What part of the cell produces ATP? 4. What part of the cell transports materials throughout the cytoplasm? 5. What part of the cell has a cis and a trans face?
https://www.youtube.com/watch? v=1Z9pqST72is&feature=youtu.be
a. ________________ b. ________________ c. _________________ d. _________________ e. _________________ f. __________________
f.
Find the: a. Nucleolus b. Centriole c. Vesicle d. Smooth ER e. Lysosome
Figure 4.7b
A
B C D E AB AD AC
What is this structure?
What is this structure?
Terms / Concepts for Show, Don't Tell cell_theory mitochondria chloroplast prokaryote protein_synthesis eukaryote nucleus lysosome ribosome endoplasmic_reticulum cytoskeleton golgi_apparatus enzyme messenger_RNA chromatin phospholipid_bilayer
cilia flagella microscope peroxisome
Single Cheek Cell - at different illuminations
Light Microscope
10X
40X
4X 10X
7
8 8 9 13
5
1. eyepiece 2. body tube 3. fine adjustment knob 4. nosepiece 5. scanning objective 6. low power objective 7. high power objective 8. diaphragm 9. light 10. coarse adjustment 11. arm 12. stage clip 13. base
Functions
1. eyepiece (ocular) – contains a lens capable of 10X magnification 2. body tube-the long tube that holds the eyepiece and connects it to the objectives 3. fine adjustment knob- brings objects slowly into fine focus 4. nosepiece – rotates to change from one lense to another 5. scanning objective - contains a lens capable of 4X magnification 6. low power objective -- contains a lens capable of 10X magnification 7. high power objective – contains a lens capable of 40X magnification 8. diaphragm- controls the amount of light 9. light – directs light into the scope. 10. coarse adjustment knob – brings objects into rapid focus - DO NOT use with high power objective 11. arm-part of the microscope that is held to carry the scope. 12. stage - holds the slide 13. base - supports the microscope, hold to carry.
Using Microscopes List the 6 steps to focus the microscope. 1. Place the prepared slide on the stage. 2. Move the slide so the beam of light goes through the middle. 3. Turn the coarse adjustment knob so the stage is all the way at the top. 4. Use the scanning 4X power objective and the coarse adjustment knob, focus down until you see the object. 5. Using the 10X power objective focus again until you see the object. To Focus on high power: Before you turn in the 40X objective: make sure the specimen is in the middle of the field of view. 6. Turn in the 40X objective. Focus only using the fine adjustment knob Turn off light and clean up when finished.
A good example of how to sketch from your microscope
raw this on the back of your handout.
Rules for Microscope Drawings" "
1. 2. 3. 4.
All drawings in pencil." use color only when you see a specific color." Draw a circle to represent the field of vision." Label outside the circle, include magnification and name of what you are looking at." 5. Be neat, label when possible " Magnification will always be 40x, 100x, or 400x
Magnification = Eyepiece X Lenses 10
4x, 10x, or 40x
Ameba with 40X lens
Ameba
400X 10 X 40 = 400
Other Rules! 1. Be very careful they are fragile 2. You break, you buy (and microscopes are expensive) 3. Don’t force anything, if the scope is not working, stop and ask for help
