Unit 3: Microscopes, cells and Viruses pp. 191-200

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

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

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

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

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

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

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

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)

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”)

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

Eukaryotic cell structures Eukaryotes: “true nucleus”

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

Nucleus _____________ of the cell. Genetic information stored as ____________, which is _______wrapped in ________________. Control center chromatin DNA protein Found in Both Plants & Animals

Nucleolus Small, dense region in the nucleus. Site of ________________ production ribosome Found in Both Plants & Animals

Nuclear Envelope Double _________________ membrane. Has nuclear ___________ which allow _______ to leave the nucleus phospholipid pores RNA Found in Both Plants & Animals

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

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

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

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

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

Vacuole Sacs that may be used as storage for _______, _________, _________________, or wastes. Plants have a large central vacuole. water Salts, proteins carbohydrates

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

Chloroplast Found in ______ cells. Contain __________ (green pigment) and their own ______. Chloroplasts harvest energy from the ____ to produce ____ through __________. plant chlorophyll DNA sun ATP photosynthesis

Centrioles Found in _________ cells only. Bundles of _________________ that play a role in _________________ animal microtubules cell division

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

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

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