PPT-Chapter 20 Viruses and Prokaryotes

Viruses A nonliving particle made of proteins nucleic acids and sometimes lipids fats Viruses only reproduce by infecting living cells Most viruses can only be seen with an electron microscope. Eubacteria & . Archarbacteria. Prokaryotes. Unicellular organisms that lack a nucleus. Prokaryotes are identified by characteristics such as shape, the chemical nature of their cell walls, the way they move, and the way they obtain energy.. Prokaryotic . Structure. size1-5. m. m (resolution of the human eye ~750. m. m). . Cell wall. . main component is peptidoglycan (modified sugar polymers). . can be further differentiated performing a gram stain . 21.4 Prokaryotes—Enduring, . Abundant, and Diverse. Prokaryotes. Structurally simple cells that lack a nucleus. Evolved before eukaryotes . Abundance and Metabolic Diversity. Prokaryotes are Earth’s most abundant organisms. Cellular organisms. In one of two domains: . Archaea. and Eubacteria. Generally smaller than eukaryotes. Most are unicellular, some form colonies or filaments. No membrane-enclosed organelles. Ribosomes are located in the cytoplasm. . Copyright © Houghton Mifflin Harcourt Publishing Company. Unit 2. . Lesson 1 . Archaea, Bacteria, and Viruses. Sized Extra-Small. Copyright © Houghton Mifflin Harcourt Publishing Company. All living things are either prokaryotes or eukaryotes.. © 2017 Pearson Education, Inc.. Introduction. A . virus . is an obligate, intracellular parasite . Viruses enter a . host. . cell. and use the host’. s biosynthetic machinery to reproduce and synthesize its proteins. 0. PROKARYOTES. 16.7. Prokaryotes have inhabited Earth for billions of years. Prokaryotes are the oldest life-forms. And remain the most numerous and widespread organisms . Colorized SEM 650. . . Chapters 27 and 19. YOU MUST KNOW. The key ways in which prokaryotes differ from eukaryotes with respect to genome, membrane-bound organelles, size, and reproduction. How horizontal acquisition of genetic information occurs in prokaryotes via transformation, conjugation, and transduction. GET READY TO USE THEM. STAND UP NOW . WITH CLICKERS IN HAND. WHEN I GIVE THE SIGNAL,. HOLD YOUR BREATH AS LONG AS YOU CAN.. I will count the time off.. When you can’t hold your breath any longer,. microscopic single celled organisms. collective biomass – . 10x of all eukaryotes!!!!!. vast genetic diversity among members. physical diversity. shapes: . spheres (. coccus. ), rods (bacilli) and spirals. Study Material for. . . B.Sc. Part II. . Botany . Hons. .. . . Paper IV. . Dr. Pushpanjali Khare. Sr. . What makes these two cell classes different?. Cells. The . cell. is the smallest unit of life in the universe.. ALL cells have two things in common:. They have . cell membranes. , which are barriers that separate the inside of a cell from the outside.. As a group discuss for 1 minute. Be able to defend your answer for the class!. Are . VIRUSES. alive?. Growth and Development. Reproduce. Change Over Time. Obtain and Use Energy. Maintain Homeostasis. Classifying Prokaryotes. The smallest and most abundant microorganisms on Earth are . prokaryotes. —unicellular organisms that lack a nucleus. . Prokaryotes have DNA, like all other cells, but their DNA is not found in a membrane-bound nuclear envelope as it is in eukaryotes. Prokaryote DNA is located in the cytoplasm. .