Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Is a Virus ? All living things are made of cells, are able to grow and, and are guided by information stored in their are segments of nucleic acids contained in a protein coat. Viruses are not cells. Viruses are —agents that cause disease. Viruses do not grow, do not have homeostasis, and do not Viruses

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Viral Structure The virus protein coat, or, may contain either RNA or DNA, but not both. Many viruses have a membrane, or, surrounding the capsid. The envelope helps the virus enter cells. It consists of proteins, lipids, and, which are proteins with attached carbohydrate molecules that are derived from the host cell. Viruses

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Viral Reproduction Viruses must rely on living cells ( ) for replication. Before a virus can, it must first infect a living cell. An animal virus enters its host cell by A bacterial virus, or bacteriophage, punches a hole in the bacterial cell wall and injects its into the cell. Viruses

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Viruses

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Important Viral Diseases – like (vaccinations can help prevent some) Viruses

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bacterial Structure Bacteria differ from in at least seven ways. Bacteria are prokaryotes. Unlike eukaryotes, prokaryotes lack a cell nucleus. Most bacterial cells are about 1 µm in diameter; most eukaryotic cells are more than times that size. Bacteria

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bacterial Structure, continued All bacteria are Bacterial chromosomes consist of a single circular piece of. Eukaryotic chromosomes are linear pieces of DNA that are associated with proteins. Bacteria reproduce by, a process in which one cell pinches into two cells. Bacteria

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bacterial Structure, continued Bacteria have many metabolic abilities that eukaryotes lack. For example, bacteria perform several different kinds of and aerobic processes, while are mostly aerobic organisms. Bacteria

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bacterial Cell Shapes A bacterial cell is usually one of three basic shapes:, a rod-shaped cell;, a round-shaped cell; or, a spiral cell. Members of the kingdom Eubacteria have a made of peptidoglycan, a network of polysaccharide molecules linked together with chains of Outside the cell wall and membrane, many bacteria have a gel-like layer called a Bacteria

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bacteria

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bacterial Cell Shapes, continued Eubacteria can have two types of cell walls, distinguished by a dye staining technique called the Positive = purple, negative = pink. Gram staining is important in medicine because the two groups of eubacteria differ in their susceptibility to different Antibiotics are chemicals that interfere with life processes in Bacteria

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bacteria

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Important Bacterial Diseases – ( ) Bacteria

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Importance of Bacteria Food and Production Many of the foods that we eat, such as pickles, cheese, sauerkraut, olives, vinegar, and sourdough bread, are processed by specific kinds of Humans are able to use different bacteria to produce different kinds of chemicals for uses. Genetic engineering companies use genetically engineered bacteria to produce their many products, such as drugs for medicine and complex chemicals for Bacteria

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Diversity Characteristics The kingdom consists of an unusually diverse assortment of eukaryotes that exhibit a broad array of characteristics. Some protists are photosynthetic (like plants), some ingest food (like animals), and some absorb their Protists are found almost everywhere there is water. Many live in lakes and oceans, floating as plankton or anchored to rocks. There are about protista species Characteristics of Protists

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Protist – algae Classified in phyla based on color. Some cause red tide. Some are microscopic, some large seaweed. Diatoms = have flagella Spirogyra = & spiral shaped Volvox =, green algae – moves like a little animal, but has chlorophyll like a plant, has sexual & asexual reproduction Characteristics of Protists

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Structure of Euglena – has chlorophyll, moves like an, also eats other things Protist Diversity

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Diversity, continued What Unites Protists? The kingdom Protista contains all that cannot be classified as animals, plants, or fungi. The major phyla of protists are very different from one another and, with a few exceptions, are only distantly Historically, scientists have referred to heterotrophic protists as protozoa and to photosynthetic protists as Characteristics of Protists

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Protozoa Protozoa means first animals. They are Some are free living and some Most are heterotrophic. The respond using and eyespots. Some are classified according to Some cause malaria, african sleeping sickness, dysentary (caused by amoeba – protist, moves by )

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ameboid Movement Amoebas, members of the phylum Rhizopoda, are protists that move by using flexible, These extensions are called from the Greek words pseudo, meaning “false,” and podium, meaning “foot.” During movement, a pseudopodium bulges from the cell surface, stretches outward, and anchors itself to a nearby surface. Protist Diversity

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Paramecium (reproduce by ) has cilia – eat smaller organisms Protist Diversity

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Diseases Caused by Protists and Health

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Protists and Humans, continued Beneficial Protists Cattle could not digest the cellulose in the hay and grass they eat without the aid of in their digestive tract. Protists are also the single largest group of on the planet. Many protists are also detritivores, so they help recycle important chemicals, such as nitrogen, carbon, and phosphorus, in the Protists and Health

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Kingdom Single celled or many celled Not Many are (break down dead things) Reproduce sexually or asexually (some both ways) Ex.: mushrooms, Used for making blue cheese, beer, wine, bread, penicilin Some cause diseases like athlete’s foot,