Presentation on theme: "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."— Presentation transcript:
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 pre- existing 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?
Early Contributions Hooke Leeuwenhoek Schleiden Schwann Virchow
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
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.)
Create a diagram comparing prokaryotic and eukaryotic cells. Include examples of each and anything you can remember In your notes: When done, use ch 4 to label the pictures on your notes outline handout pg 65 and 68
Prokaryote Eukaryote Cells DNA Cytoplasm Nucleus Plasma Membrane Ribosome Cell wall Membrane Bound Organelles Specific in function Complex Multicellular Plants, Animals, fungi No Organelles Mostly single cells Simple Archaea and bacteria both
Quick Recap 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, to help
Prokaryotic or Eukaryotic? 1.Has membrane bound organelles 2.Includes plant and animals cells 3.Bacteria Has no organelles 12 P P P E 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) Phoenix Learning Group And a shorter video on the main parts of The CellThe 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
Includes: a. Nuclear envelope b. Membrane of the ER c. Golgi apparatus d. Several types of lysosomes III. Endomembrane System:
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
Figure 4.10a Rough ER --has ribosomes --functions in protein synthesis 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 -- 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 SachsArticle and Video on Tay Sachs 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
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)
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 Cytoskeleton- support system
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 Arrangement of microtubules 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 peroxide- metabolizing 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
QOD: 1. What does the cell theory state? 2. Explain why cells are so small using the idea surface- area- to- volume ratio. 3. 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
QOD: Proteins in the Cell 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=1Z9p qST72is&feature=youtu.be
a. ________________ b. ________________ c. _________________ d. _________________ e. _________________ f. __________________ f.
Find the: a. Nucleolus b. Centriole c. Vesicle d. Smooth ER e. Lysosome