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End Show Slide 1 of 31 Copyright Pearson Prentice Hall Cells: Prokaryotes v. Eukaryotes (extracts of 7-1 & ch19)

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Presentation on theme: "End Show Slide 1 of 31 Copyright Pearson Prentice Hall Cells: Prokaryotes v. Eukaryotes (extracts of 7-1 & ch19)"— Presentation transcript:

1 End Show Slide 1 of 31 Copyright Pearson Prentice Hall Cells: Prokaryotes v. Eukaryotes (extracts of 7-1 & ch19)

2 End Show 7-1 Life Is Cellular Slide 2 of 31 Copyright Pearson Prentice Hall The Discovery of the Cell In 1665, Robert Hooke used an early compound light microscope to look at a thin slice of cork, a plant material. Early Microscopes

3 End Show 7-1 Life Is Cellular Slide 3 of 31 Copyright Pearson Prentice Hall The Discovery of the Cell At the same time, Anton van Leeuwenhoek used a microscope to observe pond water and other things. Early Microscopes Daphnia – water insect

4 End Show 7-1 Life Is Cellular Slide 4 of 31 Copyright Pearson Prentice Hall The Discovery of the Cell In 1838, Matthias Schleiden – all plants were made of cells. In 1839, Theodor Schwann – all animals were made of cells. In 1855, Rudolph Virchow – new cells were created only from division of existing cells. These discoveries led to the cell theory. What is the cell theory?

5 End Show 7-1 Life Is Cellular Slide 5 of 31 Copyright Pearson Prentice Hall The Discovery of the Cell Scientific Theory: A well tested explanation that unifies a broad range of observations. Scientific Theory used to make accurate predictions about new observations and situations. Scientific Theory can be revised according to new evidence Cell Theory is a SCIENTIFIC THEORY!

6 End Show 7-1 Life Is Cellular Slide 6 of 31 Copyright Pearson Prentice Hall The Discovery of the Cell All living things are composed of one or more cells. Cells are the basic units of structure and function in living things. »Use genetic code (DNA) »Over generations mutations accumulate and lead to changes over time »Get energy and materials from environment to run cellular metabolism »Respond to the external environment »Maintain homeostasis (stable internal environment) New cells are produced from existing cells. »Grow and develop cell theory

7 End Show 7-1 Life Is Cellular Slide 7 of 31 Copyright Pearson Prentice Hall Exploring the Cell Light microscope V. Electron microscope Electron Microscope Up to 100,000X Preserved cells only Scanning EM (3D image) Transmission EM (2D cross section) Light micrograph (LM) Up to 1000X Live or preserved cells TEM SEM

8 End Show 7-1 Life Is Cellular Slide 8 of 31 Copyright Pearson Prentice Hall Figure 4.4 DNA kept separate from the cell’s cytoplasm by the nuclear membrane

9 First cells (prokaryotic) 3.5 billion years ago Eubacteria: common bacteria UC First Eukaryotes (Has nucleus) Scientist’s study of different organisms’ cell structure and DNA lead them to group organisms into 3 different domains Archae- bacteria : Oldest bacteria type UC Protists Plants Fungi Animals UC&MC MC UC&MC MC UC = unicellular MC= multicellular

10 End Show 7-1 Life Is Cellular Slide 10 of 31 Copyright Pearson Prentice Hall Prokaryotes and Eukaryotes Prokaryote focus: The smallest, simplest life forms are prokaryotes—unicellular organisms that lack a nucleus. Biologists divided them into two different domains: the Eubacteria and the Archaebacteria.

11 End Show 19–1 Bacteria Slide 11 of 40 Copyright Pearson Prentice Hall Classifying Prokaryotes Archaebacteria- Ancient bacteria Achaebacteria’s DNA is more similar to eukaryotes than eubacteria!. They live in extreme environments (why also known as extremeophiles) ●Methanogens live in oxygen- free environments, such as thick mud and animal digestive tracts. ●Other archaebacteria live in salty environments ● or in hot springs where water temperatures approach the boiling point.

12 End Show 19–1 Bacteria Slide 12 of 40 Copyright Pearson Prentice Hall Classifying Prokaryotes Thermophiles of Yellowstone Produce Beautiful colors This type of Extremophile requires temperatures above 45oC (113oF) to survive. Wow: for most organisms, proteins and nucleic acids would denature at these hot temperatures. Thermophiles source of enzymes used in DNA biotechnology Grand Prismatic Spring Yellowstone.

13 End Show 19–1 Bacteria Slide 13 of 40 Copyright Pearson Prentice Hall Classifying Prokaryotes Eubacteria include organisms that live in a variety of environments, including: ●in fresh and salt water ● on land ●in the human body

14 Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings Structures of Prokaryotic Cells Nucleoid region – area where DNA is coiled in the cytoplasm. DNA is in direct contact with the rest of the cell Plasmid – smaller circular DNA molecules – stores genes easily shared with other bacteria Ribosomes – where proteins are made cell membrane – encloses the cytoplasm of the prokaryotic cell, regulates what chemicals enter and leave the cell. DNA Pili Plasmid Ribosome Flagella

15 Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings Structures of the Prokaryotic Cell Cell wall – rigid, composed of lipids, carbohydrates and protein. Protects the cell and maintains its shape Pili – short surface projections found in some prokaryotes. Helps attach bacteria to surfaces Flagella – long whiplike extensions found in some prokaryotes. Propel cell through liquid environments Not all bacteria the a same shape! Bacilli (rod) Cocci (round) Spirilla (spiral)

16 End Show 19–1 Bacteria Slide 16 of 40 Copyright Pearson Prentice Hall Importance of Bacteria Bacteria are vital to the living world. Autotrophs: Some are producers that capture energy by photosynthesis. Heterotrophs: using living organisms as food source. ●decomposers ●Nitrogen fixing bacteria ●Pathogens: cause disease Some bacteria damage the cells and tissues directly by breaking down the cells for food. Others By produce toxins that makes you sick

17 End Show Slide 17 of 29 Copyright Pearson Prentice Hall Bacterial Disease in Humans Bacterial Disease Growth of pathogenic bacteria disrupts the body’s equilibrium by interfering with its normal activities and producing disease. Antibiotics Chemicals that kill bacteria w/o harming your cells –Ex: Penicillin disrupts bacterial cell wall production –Does not work on Viral infections 19–3 Diseases Caused by Bacteria and Viruses Bacterial Diseases

18 End Show 19–1 Bacteria Slide 18 of 40 Copyright Pearson Prentice Hall Importance of Bacteria Still other bacteria have human uses. ●foods ●Genetically engineered bacteria used to produce medicine ●production of some vitamins especially vitamins K in human intestines

19 End Show 7-1 Life Is Cellular Slide 19 of 31 Copyright Pearson Prentice Hall Prokaryotes and Eukaryotes Compare & Contrast: What are the characteristics of prokaryotes and eukaryotes?

20 End Show 7-1 Life Is Cellular Slide 20 of 31 Copyright Pearson Prentice Hall Prokaryotes and Eukaryotes Prokaryotes Prokaryotic cells have genetic material that is not contained in a nucleus. –do not have membrane-bound organelles. –cells are generally smaller and simpler than eukaryotic cells. –Bacteria (both archaebacteria and eubacteria) are prokaryotes.

21 End Show 7-1 Life Is Cellular Slide 21 of 31 Copyright Pearson Prentice Hall Prokaryotes and Eukaryotes All cells have DNA to store hereditary information but where is it in the cells? Eukaryotes have a nucleus – DNA surrounded by a a nuclear envelope membrane separating DNA from the rest of the cell Eukaryotes have membrane bound organelles – like mitochondria and Endoplasmic Reticulum

22 End Show 7-1 Life Is Cellular Slide 22 of 31 Copyright Pearson Prentice Hall Prokaryotes and Eukaryotes Eukaryotes ●Cells highly specialized ●In multicellular species groups of cells can form tissues

23 End Show 7-1 Life Is Cellular Slide 23 of 31 Copyright Pearson Prentice Hall Prokaryotes and Eukaryotes Eukaryotic cells: Build the structures of Plants, animals, fungi, and protists.

24 End Show 7-1 Life Is Cellular Slide 24 of 31 Copyright Pearson Prentice Hall Prokaryotes and Eukaryotes Compare and contrast ProBoth Eu


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