Eukaryotic Cells Ch3.2 7th Pdf

Eukaryotic Cells Chapter 3 Section 2

Objectives • Identify the different parts of a eukaryotic cell • Explain the function of each part of a eukaryotic cell

Cool Background info… • “Protein” Therapy (i.e. gene therapy) – Use of genetic material to cure disease – A gene is the recipe for the proteins essential to life

• For example: Duchenne muscular dystrophy – Lack dystrophin (muscle protein that maintains the structure of muscle) – Researchers are using viruses to deliver dystrophin to muscle cells http://www.biosci.ohio-state.edu/~prg/protein1.gif

Eukaryotic Cells • 2 types: – Animal cells – Plant cells

*Many cell parts in common, some differences…

Cell Wall • Outermost structure on a plant cell • Rigid structure that gives support to the cell • Made of a complex sugar called: cellulose

http://www.uvm.edu/~inquiryb/webquest/fa06/mvogenbe/plantcell.jpg

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/cellulosem.jpg

Cell Wall • Fungi (yeasts & mushrooms) have cell walls • Made of a complex sugar called: chitin • Prokaryotic cells (bacteria/archaea) have cells walls too, but they are different)

http://nutrition.jbpub.com/resources/images/images/fiber.gif http://home.earthlink.net/~ggda/yeast_cell_final_resample.jpg

Cell Membrane • All cells have a cell membrane • Protective barrier that encloses the cell • Location of the membrane (depends on cell wall) • Contains: – Proteins – Lipids – Phospholipids

Cell Membrane • Phospholipid (contain phosphorus) bi-layer • Lipids: “water fearing” or hydrophobic – Hydrophilic heads – Hydrophobic tails

http://www.biologycorner.com/resources/lipidbilayer.gif

Cell Membrane • Some of the proteins and lipids control the movement of materials in and out of the cell • Some proteins form passageways • Nutrients move into the cell, wastes move out

Cytoskeleton • • • •

Web of proteins in the cytoplasm Acts as both a muscle and a skeleton Keeps the cell’s membranes from collapsing 3 types of protein: hollow tube, stringy fibers

http://www.bio.miami.edu/~cmallery/255/255hist/mcb1.15.cytoskeleton.jpg

Nucleus • Large organelle in all eukaryotic cells • Contains cell’s DNA (how to make a cell’s proteins) • Proteins control the chemical reactions of a cell • Proteins provide structural support for cells and tissues • Proteins are not made in the nucleus

Nucleus • Covered by 2 membranes • Materials cross the double membrane through pores • Dark area: nucleolus (ribosome production beings here)

http://kconline.kaskaskia.edu/bcambron/Biology%20117/Cells_files/image004.jpg

Ribosomes • Organelles that make proteins • Ribosomes are made of RNA and protein • Smallest of all organelles • More ribosomes in a cell than any other organelle • Some float freely, others are attached to membranes or the cytoskeleton

Ribosomes • Proteins are made within the ribosomes – “site of protein synthesis” • Proteins are made of amino acids

• Amino acids are one of about 20 different organic molecules that are used to make proteins • Cells need proteins to live

Ribsomes

http://s3cg8biology_project.tripod.com/ribosomes.gif

http://www.molecularexpressions.com/cells/ribosomes/images/ribosomesfigure1.jpg

Endoplasmic Reticulum (ER) • Where many chemical reactions within the cell take place • System of folded membranes in which proteins, lipids, and other materials are made • Internal delivery system of the cell (tubes and passageways)

Endoplasmic Reticulum (ER) • Rough ER – Covered with ribosomes – Found near the nucleus – Make many of the cell’s proteins

• Smooth ER – Make lipids – Break down toxic materials that could damage the cell

Endoplasmic Reticulum (ER)

https://illnessesanimalsplants.wikispaces.com/file/view/smooth_&_rough_ER.jpg

Mitochondria • Main power source of the cell (site of cellular respiration) • Sugar is broken down to produce energy • Covered by 2 membranes • Energy is stored in ATP (adenosine triphosphate) • Mitochondria are the size of some bacteria • Have their own DNA, can divide within a cell

Mitochondria

http://giantshoulders.files.wordpress.com/2007/10/mitochondria.jpg

Chloroplasts • Organelles in plant and algae cells which photosynthesis takes place • 2 membranes and their own DNA • contain chlorophyll, a green pigment • Chlorophyll traps the energy of sunlight to make sugar • Sugar produced by photosynthesis then used by mitochondria to make ATP

Chloroplasts

http://virtualbiologytutor.co.uk/images/chloroplast.jpg

Golgi Complex • Organelle that packages and distributes proteins • Looks like smooth ER • Lipids & proteins from the from the ER are delivered here • “bubbles” are pinched off to be transported to other parts of the cell

Golgi Complex

http://bioweb.wku.edu/courses/Biol22000/11Organelles/images/F05-49.JPG

Cell Compartments • “bubble” formed from Golgi complex is called a vesicle • Vesicles more material in and out of cells

http://www.williamsclass.com/SeventhScienceWork/ImagesCells/vesicle.jpg

Cellular Digestion • Lysosomes are responsible for digestion inside a cell • Lysosomes are organelles that contain digestive enzymes • Destroy old organelles, rid cell of waste, and protect from invaders • Found mainly in animal cells • Bump into vesicles, pour enzymes in, and digest the particles

http://www.easthaven.k12.ct.us/dcmoore/Grade%206/Cell%20Websites/angelica_files/lysosome.png

Vacuoles • A vacuole is a vesicle • In plants and fungi: – Store digestive enzymes – Aid in digestion – Large central vacuole stores water & other liquids – Support the cell

http://www.odec.ca/projects/2004/mcgo4s0/public_html/t4/plantcell.gif

Quick Quiz • Why do scientists sometimes say that some plant cell vesicles are just large lysosomes? • What is the difference between the cytoskeleton and the cytoplasm?