Cell Structure and Function - mgaughan …

1 Cell Structure and FunctionChapter 7 Freshwater diatoms unicellular algae with hard silica cell wall come in many shapes and OverviewLife Is CellularChapter Mystery Death Michelle was a healthy 25-year-old running in her first marathon. The hot and humid weather had made all the runners sweat profusely, so Michelle made sure to drink water at every opportunity. Gradually, she began to feel weak and confused. At the end of the marathon, Michelle staggered into a medical tent. Complaining of a headache and nausea, she collapsed onto the floor.

2 Volunteers quickly gave Michelle water for dehydration Soon, her condition worsened and Michelle was rushed to the hospital, where she was gripped by a seizure and went into a coma. Why did treating Michelle with water make her condition worse?As you readthis chapter, look for clues to help you predict how water made Michelle is CellularSection diatoms unicellular algae with hard silica cell wall come in many shapes and OverviewLife Is Cellular The building blocks of living things Some organisms are made of 1 cell Unicellular (bacteria) Some organisms are made of many cells Multi-cellular (plants, animals)

3 Lesson OverviewLife Is CellularEarly Microscopes 1665 Robert Hooke, Englishman used microscope to observe piece of corkcoined the term cells -Made of many tiny compartments, like rooms in a monastery called cells Lesson OverviewLife Is CellularEarly Microscopes Anton van Leeuwenhoek: the first to observe living microorganisms. using a microscope, found organisms in pond water, drinking water, and even his mouth-The drawings on the above show bacteria in the human OverviewLife Is CellularThe Cell Theory cells basic unit of life cells are many different shapes and sizes But all cells have a Cell membrane thin, flexible barrier that surrounds the cell Cell Theory:-All living things are made up of are the basic units of Structure and Function in living cells are produced from existing OverviewLife Is CellularLight Microscopes Light microscopes.

4 Allow light to pass through a specimen and uses two lenses to form an image Light microscopes can see cells and cell structures use stains Can be magnified up to 500x Using chemical stains or dyes can allow us to see structures within living cell, which are nearly transparent -Some of these stains are so specific that they reveal only compounds or structures within the OverviewLife Is CellularElectron Microscopes Electron microscopes use beams of electrons, not light, that are focused by magnetic fields. Electron microscopes offer much higher resolution than light microscopes.

5 Electron microscopes (2 types) electron microscope produces dramatic 3D images-Have 3750x magnification2. Transmission electron microscope samples are cut in thin slices, making a flat 2D image-Have 4375x magnificationLesson OverviewLife Is CellularElectron Microscopes Scanning electron microscope: use a pencil-like beam of electrons that is scanned over the surface of a specimen-specimens do not have to be cut into thin slices-can only view nonliving cells and tissues that have been preserved-produce 3D images of specimen s surface Lesson OverviewLife Is CellularElectron Microscopes Transmission electron microscope.

6 Make it possible to explore cell structures and large protein molecules-samples must be cut into ultra thin slices-produce flat, 2D imagesLesson OverviewLife Is Cellular cells fall into 2 broad categories, based on the presence or absence of a _____ _____ = large, membrane-enclosed Structure that contains genetic material called DNA Prokaryotes (bacteria) Eukaryotes (animals, plants)Lesson OverviewLife Is CellularProkaryotes and Eukaryotes* All cells contain the molecule that carries biological information DNA. * All cells are surrounded by a thin, flexible barrier called a cell OverviewLife Is CellularProkaryotes and Eukaryotes* cells fall into two broad categories, depending on whether they contain a nucleus.

7 * Nucleus:a large membrane-enclosed Structure that contains the cell s genetic material in the form of DNA. -The nucleus controls many of the cell s activities. Lesson OverviewLife Is CellularProkaryotes and EukaryotesEukaryotes: cells that enclose their DNA in nuclei. Prokaryotes: cells that do not enclose DNA in OverviewLife Is CellularProkaryotes Smaller Simple Grow, reproduce, and respond to environment Some can move by gliding along surfaces or swimming through liquids Example: bacteria Lesson OverviewLife Is CellularEukaryotes Larger More Complex Highly specialized Contain dozen of structures and internal membranes Examples.

8 Plants, animals, fungi, protistsLesson OverviewLife Is CellularProkaryotes No nucleus (DNA floats freely) Unicellular Small and simple Some swim or glide along surfacesEukaryotes Nucleus (contains DNA) Multi-cellular Large and complexLesson OverviewLife Is Cellular No, it is not a cell, and it is not alive Viruses are nonliving particles Made of proteins, nucleic acids (DNAor RNA), and sometimes lipids (fats) Can ONLY reproduce by infecting living cells (remember cell theory?)Lesson OverviewLife Is Cellular Many shapes and sizes All very small need what type of microscope.

9 ? Viruses have a protein coat called a capsid Bacteriophages virus that infects bacteria Once inside bacteria, it makesmany copies of itself Breaks open and infects other cellsLesson OverviewLife Is CellularMystery Clue #1 At the hospital, a sample of Michelle s blood was drawn and examined. The red blood cells appeared swollen. What kind of microscope was most likely used to study the blood sample?Cell StructureSection diatoms unicellular algae with hard silica cell wall come in many shapes and OverviewLife Is CellularCell Organization* Cytoplasm: fluid portion of the cell outside the nucleus, contains all the organelles of the cell* Organelle: specialized cellular structureLesson OverviewLife Is CellularComparing the Cell to a Factory The eukaryotic cell is much like a living version of a modern factory.

10 The specialized machines and assembly lines of the factory can be compared to the different organelles of the cell. cells , like factories, follow instructions and produce OverviewLife Is CellularThe Nucleus In the same way that the main office controls a large factory, the nucleus is the control center of the :-all the cell s DNA-instructions for making proteins and other moleculesLesson OverviewLife Is CellularThe Nucleus -Nuclear Envelope: two membrane Structure that surrounds the nucleus-Nuclear Pores: dot the nuclear envelope, allows substances to pass into and out of nucleus-Nucleolus.