Midterm 2 Flashcards
what is the difference in the structure of gram negative and gram positive bacteria?
gram negative has two pairs of rings in the basal body, gram positive has only an inner pair of rings attached to the plasma membrane.
how is movement in bacteria achieved?
through the rotation of flagellum from ht e basal body clockwise or counter clockwise
what is the difference between a run or a tumble in flagellar movement?
run is one directional and a tumble is an abrupt change in direction
what are the 4 main types of bacterial movement and describe each?
1) taxis: toward or away from a stimulus
2) chemotaxis: toward or away from a chemical
3) phototaxis: toward or away from light
4) magneto taxis: toward or away from a magnetic feild
what is bacterial movement based on?
chemotactic signal
what are the two chemotactic signals?
positive(attractant), negative (reppellant)
are structures external to the cell wall on gram negative or positive bacteria?
-
what is the difference between pilli and fimbriae?
both external structures:
pilli-> longer, one or two per cell, role where two bacterial cells are joined for transfer of dna from one cell to another
finbriae-> few or several hundred, adherence to other cells
what is the difference between micro and macronutrients?
micro are needed in trace elements, macro are C,N,P
What are growth facotrs?
vitamins
what are the two classes of culture media and what is the difference?
chemically defined: the exact chemical composition is known
undefined or complex: uses digests of animal or plant products, composition not known
what is a selective medium?
has compounds that selectively inhibit the growth of some microorganisms but not others
what is a differential medium?
contains and indicator that distinguishes between chemical reactions
how many organisms does a pre culture contain?
one
what is an amphibolic pathway?
uses both catabolism and and anabolism
what does it mean by microbial metabolism being differentiating?
the chemical composition is always changing
what is free energy
energy released available to do work
what is the reaction rate?
frequency of collisions containing sufficient energy to create a reaction
what is the enzyme substrate complex?
temporary binding of enzyme and reactants, lowers activation energy
what are 4 conditions in which enzyme activity can be affected?
1) ph
2) temp
3) [ ] of substrate
4) inhibitors
what is feedback inhibition?
prevents cell from wasting chemical resources, the end product can inhibit one enzyme earlier in the pathway
what is a dehydration reaction?
oxidation reaction where H are lost
what is phosphorylation?
addition of P
what is SLP?
ATP by high energy phosphate transfer from a phosphorylated substrate to ADP
what is oxidative phosphorylation?
electrons are transferred to electron carriers to oxidized molecules
where does oxidative Phosphorylation occur?
plasma membrane of prokaryotes
where does photophosphorylation occur and what is it?
photosynthetic cells, light energy converted to atp and nadph
what is carbohydrate catabolism?
breakdown of carbohydrate molecules to produce energy
what processes are involved in glucose catabolism?
cellular resp, and fermentation
in what 3 systems in glucose used?
glycolysis, krebs and etc
what are the two alternatives to glycolysis?
pentose phosphate pathway and the enter doudoroff pathway
what leads to plasmolysis?
intolerant bacteria suffer loss of H2O internally to external environment
what is an obligate aerobe?
requires O
what is a facultative anaerobe?
can or cannot use O
what are 4 toxic forms of Oxygen?
singlet oxygen, superoxide free radicals, peroxide anion, hydroxyl radical
what are aerotolerant anaerobes?
cannot use oxygen for growth, but can live in it
what are micronucleophiles?
grow at low oxygen tension but don’t require for growth
what are 3 enzymes that destruct toxic oxygen?
catalase, peroxidase, superoxide dismutase
what is nitrogen useful for?
formation of amino acids
what is Sulfur usefor for?
used in amino acids and vitamins
what is phsphate essential for?
nucleic acid synthesis, phospholipid membrane structure
