Micro Exam 1 Review Sheet PDF

IMPORTANT CONCEPTS FROM CHAPTER 1: Naming: Genus species or Genus species When naming species, you name the Genus first, then the species. You then either underline or Italicize it. After naming it for the first time, you can put just the initial of the genus and the full species name. Histo...

IMPORTANT CONCEPTS FROM CHAPTER 1: Naming: Genus species or Genus species When naming species, you name the Genus first, then the species. You then either underline or Italicize it. After naming it for the first time, you can put just the initial of the genus and the full species name. History Spontaneous generation ​ Spontaneous generation is the idea that life can form from non-living matter. An example would be frogs spawning from the mud. Evidence disproving ​ This was proven untrue by Francesco Redi. This was done by taking two jars and filling one of them with decaying meat. The flies would land on the meat, and later on, maggots would appear. The other jar was sealed, and maggots never grew. However, then the idea of that the lack of oxygen is the reason for the lack of growth. The experiment was done a second time; one jar was left open, allowing flies to come in and out, while the other had a mesh lining put on top. This allowed oxygen in but kept the flies out. No maggots appeared either. ​ Biogenesis After the disproving spontaneous generation, the theory of biogenesis was developed. This is the idea that living cells come from other living cells. ​ Germ theory of disease Germ theory is the idea that “invisible” microbes can travel through the air to infect animals and plants. ​ IMPORTANT CONCEPTS FROM CHAPTER 3: Microscope Parts: ​ Ocular lens: Remagnifies the image formed by the objective lens. ​ Body Tube: Transmits the image from the objective lens to the ocular lens ​ Arm ​ Objective lens: Primary lenses that magnify the specimen ​ Stage: Holds the microscope slide in position ​ Condenser: Focuses the light through the specimen ​ Diaphragm: Controls the amount of light entering the condenser ​ Illuminator: The light source ​ Course focusing knob ​ Base ​ Fine focusing knob ​ Oil Why needed? How does it work?  You use oil at 100x because it aids in the resolution. There is less refraction of the light rays because oil’s refractive index is similar to glass. The oil prevents light from scattering, allowing it to easily go into the objective lens; without the oil, it would be too dark, or you would need a wider objective. Calculate magnification ​ -Objectives are 4,10,40,and 100. You would multiply the objective by 10. Limit of resolution -​ How much you can see Stains ​ Purpose in general – why necessary? Staining helps to see the shape and arrangement of the cells. This is needed because cells are usually colorless. Purpose for each stain specifically? What does each stain tell you? Which organisms for which stains? Simple stains: Simple stains use a single basic dye. You start off by fixing the specimen to slide. You then apply the stain and rinse it off. After that, you can view it from a microscope. This will stain the entire cell. Gram stain: A gram stain will show you which stains are gram-negative and gram-positive. To do a gram stain, you apply crystal violet to your cells. You then apply a mordant (the cells will still be purple), you then decolorize with alcohol and add Safranin. This will turn any clear cells pink. Gram-positive will be purple, and gram-negative will be pink. Negative stain: Negative staining stains the background instead of the cells themselves. Staining the background can allow the colorless capsules surrounding the cells to be seen. Acid-fast stain: Acid stains are used for cells that can’t be gram-stained; this is because of their waxy coating. To acid stain, you add carbolfuchsin dye to the cells to stain them red. You then decolorize with acid-alcohol and counter-stain with methylene blue. IMPORTANT CONCEPTS FROM CHAPTER 4: Functional anatomy ​ All cells have a plasma membrane and contain cytoplasm. They have DNA and RNA. All the cells get raw materials and energy from the environment. Shape and arrangement Diplococci Streptococci Staphylococci Single / Diplobacilli ​ Streptobacillis Coccobacillius Vibrio  Spirochete Structures ​ Glycocalyx If the glycocalyx is organized and tightly attached, it's a capsule if it's unorganized and loose, it's a slime layer. Function: adhesion and protection; It protects against dehydration and antibiotics. ​ Flagella ​ ​ Arrangements include: ​ ​ ​ Peritrichous: ​ ​ ​ ("peri": around or enclosing) ​ ​ ​ Monotrichous and polar: ​ ​ ​ ("mono": one) Lophotrichous and polar: ("lopho" : tuft or crest) Amphitrichous and polar: ("amphi": on both sides)  The flagella are worm-like structures attached to the cell wall. These help the cell move in many different directions. Rotation is to run or tumble and taxis which is away or towards something. ​ Pili Pili can transfer DNA between cells; this is called conjugation. The donor cell will attach its pilus to the recipient cell. The donor cell will then give its DNA to the recipient cell, allowing the recipient cell to have new traits, such as its own pilus. ​ Cell wall Cell walls are made of peptidoglycan. Gram-positive cells have a thick peptidoglycan layer, while gram-negative cells have an outer membrane made up of lipopolysaccharide. After the outer membrane, there is a thin layer of peptidoglycan. The cell wall is a protective barrier to protect the cell. Lps-> lipid A (endotoxin- fever, shock, etc.) Cell walls can be damaged by things such as penicillin. Penicillin will interfere with the linking of the peptidoglycan rows, weakening the cell. ​ Plasma membrane All cells have a plasma membrane. They are where diffusion occurs; this controls what comes in and out of the cell. Plasma membranes have selective permeability. This means that it can actively pass some molecules while others will have to be passed over. It also anchors enzymes for ATP production. ​ Nucleoid ​ ​ A nucleoid is a bacterial chromosome. ​ Ribosomes ​ ​ Similar to mitochondria and chloroplasts Ribosomes float freely in the cytoplasm. Prokaryotic ribosomes are 70s, which means they are made up of a small subunit (30s) and a large unit (50s). ​ Endospores An endospore is a resting cell. They can protect DNA for hundreds of years and are resistant to desiccation, heat, and chemicals. They will “reactivate” when the conditions around them are suitable for them.