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Unit 3: Microscopes, cells and Viruses
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What about Viruses? Are They Alive?
Based on what we learned in Unit 1, viruses would be considered non-living because they do not exhibit all the characteristics of life: Do not contain____________ for ____________ Not made of ________; lack a ______________ Do contain______________________________ Cannot _____________ without a ________ cell Typically referred to as a ______________ or __________ enzymes metabolism cells Cell membrane Genetic material reproduce host particle virion
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Structures of Viruses The following structures are found in all viruses: Genetic material- The genome of a virus may be either ____ or ____, but never both. It can be ____________ or ________________, _________________ or ____________. DNA RNA Single-stranded circular Double-stranded linear
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Protein coat- The DNA or RNA is surrounded by a protein coat called a capsid. The proteins making up the capsid are known as ___________ and play an important role in the _____________ of the virus. In addition, the capsid has ___________ ID tags known as _______________ which can __________ to enable the virus to escape detection by a host cell’s immune system. capsomeres pathogenicity carbohydrate glycoprotein mutate
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The following additional structures may be present:
Viral envelope- Many viruses have an outer membrane known as an envelope. A viral particle “steals” the components for its envelope from the host cell membrane, so a viral envelope is primarily composed of _________________. It aids in the attachment of the virus to the host cell, but a virus enclosed by an envelope is also more sensitive to ______________. phospholipids drying Examples of viruses with envelopes are: _________________________________ HIV, flu virus, cold virus
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Tail Fibers- Viruses that infect _________ are known as ____________
Tail Fibers- Viruses that infect _________ are known as ____________. They have “tail fibers” to aid in attachment. bacteria bacteriophages
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Viral Reproduction Two ways viruses reproduce using a host cell
Lytic infection- _____________ cycle in which viruses ____________ host cell DNA. Examples are _________________________ ___________ Lysogenic infection - _____________ cycle in which viral DNA is incorporated into ________________. Examples are __________________ symptomatic destroys Cold, flu, rabies, measles, etc… most viruses asymptomatic Host cell DNA HIV, chicken pox virus
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Viral Reproduction There are two initial steps that are common to all types of viral infections: Virus attaches to _____________ of _____________. Virus releases____________ into cell, either by _______________ typically through ____________ or ___________ genetic material into it. Cell membrane host Genetic material Entering cell endocytosis injecting
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Eu = “true” Nowadays Eubacteria usually just called Bacteria, and archaebacteria called Archaea Bacteria Bacterial make up two kingdoms, the ____________ and ____________. In this unit, we will focus on the kingdom that has the greater impact on our lives, the ________. _______________&_________________ Archaebacteria Eubacteria Eubacteria prokaryotic unicellular Pro = “before” Karyon = “kernel” (the nucleus)
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Cell Structures Cell wall composed of ________________
__________________________ ____________________ ________________________ Found in region known as ___________ peptidoglycan Eubacteria only DNA Single, circular chromosome nucleoid Cell membrane Ribosomes (protein factories) Cytosol (cell fluid or “cell gel”)
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Most bacteria are motile and have one or more ______________.
Many have hair-like appendages called _________ that allow bacteria to ________ to surfaces or other _________ Some bacteria have an outer _________; helps bacterial cells attach to a substrate or deter the host’s infection-fighting cells. flagella fimbriae bacteria adhere capsule
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Eukaryotic cell structures
Eukaryotes: “true nucleus”
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What’s inside a cell? Cell organelles which means “little organs” 1st a little clarification of a couple of terms: _______________- includes the ___________ or “cell gel” and the ________ cytoplasm cytosol organelles
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Nucleus _____________ of the cell. Genetic information stored as ____________, which is _______wrapped in ________________. Control center chromatin DNA protein Found in Both Plants & Animals
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Nucleolus Small, dense region in the nucleus. Site of ________________ production ribosome Found in Both Plants & Animals
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Nuclear Envelope Double _________________ membrane. Has nuclear ___________ which allow _______ to leave the nucleus phospholipid pores RNA Found in Both Plants & Animals
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Ribosomes Tiny, granular organelles located on _________________ or suspended in _________. Site of _________________. All cells (pro & euk) have ribosomes. Endoplasmic Reticulum cytosol protein production Found in Both Plants & Animals
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Rough Endoplasmic Reticulum
Extensive network continuous with _________________. Called “rough” because it has ________________ all along the membrane. Function of the rough ER is to _____________________. Most of these proteins are packaged into _____________ (like bubbles or sacs) and shuttled to the ____________ nuclear envelope ribosomes modify & transport proteins vesicles Golgi apparatus Found in Both Plants & Animals
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Smooth Endoplasmic Reticulum
Similar to rough ER in structure, except that it lacks ___________. The smooth ER: 1. manufactures ______, 2. breaks down _______, 3. detoxifies ________, and 4. _____________. ribosomes lipids glycogen poisons stores calcium Found in Both Plants & Animals
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Golgi Apparatus Flattened, round sacs that look like a sack of ________________. Receives, modifies, and ships products by way of ___________ into the ____________________________ pancakes vesicles cytosol → cell membrane_ Found in Both Plants & Animals
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Lysosome Found in __________ cells only. Round sacs containing __________ that _______________ and ______________ used cell components. Also used as defense against _______ and _______________ animal enzymes break down recycle bacteria viruses
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Vacuole Sacs that may be used as storage for _______, _________, _________________, or wastes. Plants have a large central vacuole. water Salts, proteins carbohydrates
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Mitochondria Double-walled organelle with inner folds ____________. ____________Uses _______ to manufacture energy in the form of ______. Mitochondria have their own _______. to increase surface area glucose ATP DNA
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Chloroplast Found in ______ cells. Contain __________ (green pigment) and their own ______. Chloroplasts harvest energy from the ____ to produce ____ through __________. plant chlorophyll DNA sun ATP photosynthesis
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Centrioles Found in _________ cells only. Bundles of _________________ that play a role in _________________ animal microtubules cell division
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Cytoskeleton Composed of protein fibers known as _______________ and ______________. Anchor _______________ and provide ______________. Also provide motility for some cells in the form of ___________ or ____________. More extensive cytoskeleton found in __________ cells. microtubules microfilaments organelles structure cilia flagella animal
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Cell Wall Cell walls are the outermost boundary in __________, _______, and ___________. They are not found in _____________________. The primary function of the cell wall is to provide ___________________________. The cell wall does not regulate what _________________________ the cell. 1. Cell walls of plants are composed of ____________ 2. Cell walls of fungi are composed of _____________ bacteria fungi plants Animal cells Structure and support Enters and leaves cellulose chitin
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Cell Membrane Every cell is surrounded by a cell membrane made of ___________________. The cell membrane is selectively permeable which means ____________________________________________. This characteristic is critical in helping the cell maintain _______________. The cell membrane is also called the ____________________ membrane Phospholipid bilayer It only allows certain substances in and certain out. homeostasis Plasma
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