Microbiology Test 1
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Line of bacteria
grape cluster of bacteria
Consider the bacterium Yersinia pestis which one is the species and which one is the genus?
- species= pestis
- genus= yersinia
Name three structures that are found in all
prokaryotic cells and all eukaryotic cells.
Cytoplasma, DNA and Ribosomes
Name at least four structures that are found in
prokaryotic cells, but not in eukaryotic cells.
Cell walls, endospores, capsules and plasma DNA
Describe two ways in which the structure of
bacterial membranes is different to that of eukaryotic cell membranes.
- They don’t have cholesterol but hopanoids,
- some bacterias have lipidpolysaccirids instead of phospholipid .
What’s the function of the bacterial cell wall?
- It’s function is to help prevent bursting from
- osmotic pressure (they are usually in hypotonic enviroment)
Do all bacteria have cell walls? Explain your answer.
- Pretty much all bacterium have it except one bacterium
- called mycroplasma they have more hyponoid protecting them.
What type of link connects the sugars together
Beta 1, 4 link
Teichoic acids are found in Gram ( negative
or positive ) bacteria.
Describe three functions/characteristics of
- The bind to magnesium ions and help bring them into the cell
- which helps them replicate DNA.
Lipoteichoic acid helps anchor peptidoglycan to the cell.
Stimulates immune response.
What’s the difference between a wall techoic acid
and a lipoteichoic acid?
- Techoic acid don’t go through the cell wall they are
- closer to the surface of the bacteria while a lipoteichoic acid goes from the surface all the way through the cell wall down to the plasma membrane.
what is Periplasm?
- – it’s the space between the outer membrane and the
- inner membrane (you can find binding protiens, p-glycans and hydrolytic enzymes (breaks down nutrient molecule) found in gram negative
What's the definition of Lipoprotein and what type of bacteria have it?
- Gram negative.
- They help anchor the outter membrane to the p-
- glycan, helps transport molecules through outter membrane.
Whats the definition of Lipopolysaccharide and what bacteria cells is it found?
- Gram negative
- helps with immune response ( 2 parts to this one, Lipid A anchors it and then sugar that makes up the strand) and it makes up the second part of the bilayer.
Lipopolysaccharide molecules are made of two
parts. What are these two parts?
Lipid A and then the polysaccharide chain
Capsules and slime layers are made what type(s)
Polysaccharides or polypeptid
What is biofilm?
- A huge mass of bacteria that are growing in one place
- that have a slime layer
Describe four differences between bacterial chromosomal DNA and plasmid DNA.
- Chromosomal is all the genes for survival every bacterium has one
- The extra space between chromosomal is plasma DNA
- Only some bacteria has plasma DNA, plasma DNA isn’t needed to survive but might provide a advantage (ex. Antibiotic resistant)
- The cells that do have plasma DNA have more then one piece of plasma DNA and some of these can be exchanged.
What’s a nucleoid?
The region where the bacterial DNA is located
Give three examples of things that are normally
harmful to “normal” bacterial cells, but not harmful to endospores.
- Extreme heat (105 C)
- UV radiation
What is sporulation?
When the cell is stress it starts to create the endospore
What is germination?
When the endospore wakes up to become a regular bacterium
Name three structures/molecules that are found in endospores, but not vegetative bacterial cells. For each structure that you name, describe its function.
- Dipicolinic acid- calcium complex helps protect the DNA and dehydrates the cell
- SAPS are attached to the DNA to help stabilize it and they serve as a nutrient source when they are germinating
- Receptors for germination outside the protein coat that senses the enviroment
How does an endospore “know” when it’s time to
The receptors outside the endospore senses for sugar and amino acids in the enviroment
Consider the protein molecules that are found inside Archea that live in extremely hot environments. What prevents these proteins from becoming denatured in the hot temperature?
They are heat stable protiens so it’s hard for the heat to unfold the protein that makes up the amino acids. The R groups in the amino acids are in the middle and are highly hydrophobic so it’s hard to unfold the proteins
Describe two things that stabilize the structure of DNA found in Archea living in hot environments.
- It has heat stable DNA which means that the sugar phosphate bond is super inforced with another bond not found in other bacteria.
- It is also very compact DNA which helps it not get denatured. There are protiens that bind to the DNA that helps it compact the DNA.
How is the membrane structure of Archea different from that of other types of cells? How does this structural difference help Archea survive in extremely hot environments?
There is going to be more reinforced with physically connected and covalently linked bilayer membrane. There hydrophobic tails are double bonded hydrogen bonds unlike regular bacteria.
uses organic molecules as a electron source (green box first part)
Uses inorganic moleciles as a electron source (green box first part)
Uses a inorganic molecule as a electron acceptor with O2 present
Uses inorganic molecule without O2 for a electron acceptor
Uses organic molecules for an electron acceptor no O2 needed
uses organic molecules as a carbon source
uses inorganic molecules as a acarbon source (like CO2)
makes NADH, somes ATP, smaller carbon containing molecules used as building blocks
PPP (pentose phosphate pathway)
makes NADPH and smaller carbon containing molecules used as building blocks
CAC (citric acid cycle)
Takes glycolysis leftovers to make NADH, FADH2 some ATP and small carbon containing molecules. (uses O2) CO2 is a by product
The CCC-P is used to make...
(from glycolysis) AA which can make proteins
CC-CoA is used to make...
fatty acids which is used for lipids in cell membranes (Found in the end of glycolysis beginning of citric acid cycle)
The CAC makes...
more AA which can make protein
In the PPP they make...
the 5 carbon can make Ribose which makes nucleotide which makes nucleic acid
Lactic acid fermentation
(curcles milk ect) Add a H from the NADH onto the pyruvic acid and you have lactic acid.
From pyruvic acid take away a carbon and make CO2 the other 2 carbons and a H from the NADH and you got ethanol
Both pyruvic acids give a carbon to CO2 the pair or 2 carbons combine into 4 carbons, add a H from the NADH becomes butanediol
Mixed acid fermination
different variations of pyruvic acid that dont make butanediol, ethanol, or lactic acid
photosynthesis with chloroplasts or cyanobacteria
uses H2o as electron source it just adds P to ADH and uses ATP synthesis
Photosynthesis with purple bacteria
H2S or H2 is used as a electron source. the NADPH, P and CO2 all go to the calvin cycle to create ATP
Photosynthesis with green bacteria
Uses H2S or H2 is used as a electron source. It goes through reverse cytric acid cycle. So it doesnt use NADPH just ferredoxin; the P and CO2 goes into the reverse CAC. Acetyl CoA is a by product that is eventually made into glucose.
What is NH3 used for and what is it's byproducts?
Some C-lithiotrophs use it as a energy source and plants and algae use it as a nitrogen source. It's by products are to make amino acids and nucleic acids and to makes NO2 to make NO3.
What is N2 used for and what is it's byproducts?
Some bacteria use it as a nitrogen source. the by products are to make NH3 to make amino acids to make nucleic acid.
What is NO2 used for and what is it's byproducts?
Some anaerobic respirators use it as a final electron acceptor. The by products are NH2/N2
What is NO3 used for and what is it's byproducts?
Some anaerobic respirators use it as a final electron acceptor; it can be used as a nitrogen source from bacteria, plants and algae. the by products are NO2 to make NH3/N2 and amino acids and nucleic acids.
Converts N2 into a form that stays in the soil and it is only odne by prokaryotes
Nitrification of the soil
converting different types of nitrogen so that other bacteria can use it
The H2N from plant amino acids is removed
The H2N from a plant amino acids is taken off and is made into ammonia
Converting NO3 to N2 gas
Can only use O2 as a final electron acceptor
cannot ise O2 as a final electron acceptor
Facultative (has a example)
Can use O2 or non-O2 molecules as a final electron acceptor, can live with or without O2 (ex. E. Coli)
Cannot use O2 as a final electron acceptor but can survive exposure to O2 (they have enzymes that protect the cell from the O2 radicals)
can only use O2 as a final electron acceptor but dies if exposed to too much O2
Have their opticmuim betwween -5C and 15C (found in antartica and glacier lakes)
Optimum is 20-30C but grow well at lower temperatures (important for food spoilage)
Optimim is 45-70C (found in hot springs and water heaters)
When the bacteria run out of nutrients
when the bacteria are getting ready for the big growth (creating protiens ect.)
When the bacteria are reproducing exponentially
When death and reproduction is equal
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