lecture exam 2 Flashcards
- obligate intracellular parasite
- nonliving and is not made of cells
virus
only purpose of a virus is to _____
replicate
where can viruses only function?
inside a living cell
- not cellular
- can only replicate inside of a host cell
- no ATP generating system
- no ribosomes
- contain only one nucleic acid
- no metabolism
why are viruses not living?
A virus that infects bacteria
Bacteriophage
viruses are diverse in ___ and ___
size / morphology
does size correlate to severity of a virus?
no
what are viruses made of?
- protein coat (capsid)
- nucleic acid
- made of capsomeres
- protects the nucleic acid
- responsible for the shape
capsid protein coat
all viruses have ____ ___ and one ___ ___
some viruses have an ____
protein coats / nucleic acid;
envelope
viruses whose capsids are not covered by an envelope
nonenveloped viruses
virus that contains additional layers around the nucleocapsid
enveloped virus
- Animal Viruses
- Plant Viruses
- Bacterial Viruses (Bacteriophages or Phages)
Virus Specificity
the formation of biological viruses during the infection process in the target host cells
Viral Replication
with a virus, the ____ ____ ____ causes damage and symptoms not the virus
immune system’s response
1) ATTACHMENT
2) PENETRATION
3) UNCOATING
4) BIOSYNTHESIS
5) late translation
6) MATURATION
7) RELEASE
steps of viral replication
in an enveloped virus, the envelope fuses with ___ ___ of the cell membrane of the host cell
lipid bilayer
what is the purpose of a virus?
to replicate more viruses
viruses release from the host cells by ____
budding
T4 bacteriophage is a very ____ virus and only infects ____
complex / E. coli B
- animal cell has entire nucleic acid and coat in cell / bacteriophage only has a nucleic acid injected into a host cell
- animal cell lysis may survive or die / bacteriophage always lyse and die
what are the 2 differences in bacteriophage viruses and animal cell viruses?
a state in which phage DNA is incorporated into the host cell without lysis
Lysogeny
the lytic cycle is ___
the lysogenic cycle is ___
common / rare
process in which a virus enters a cell, makes a copy of itself, and causes the cell to burst
lytic cycle
a viral reproductive cycle in which the viral DNA is added to the host cell’s DNA and is copied along with the host cell’s DNA
lysogenic cycle
when a bacterium acquires a new trait from its temperate phage
lysogenic conversion
bacteria that release _____, _____, and ____ must be lysogenized in order to be able to produce the toxins
botulinum toxin / scarlet fever toxin / diphtheria toxin
in general, viruses do not produce _____
toxins
what is an oncogenic virus?
cancer-causing virus in animals
how do we control viral infections?
- vaccines
- antivirals
- masks
small circular RNA molecules that infect plants and disrupt their growth
naked RNA
Viroids
potato spindle tuber disease
disease caused by viroids
infectious proteins
Prions
What does prion stand for?
proteinaceous infectious particle
how are prion diseases usually contracted?
eating prions in your diet
there are no treatment or cures for _____ diseases
prion
scrapie
Kuru
Chronic Wasting Disease
Mad Cow Disease
Creutzfeldt-Jakob disease
prion diseases
prion disease in sheep
Scrapie
Prion disease that infects humans (cannibalism - common in Papa New Guinea)
Kuru
prion disease in elk and deer
Chronic Wasting Disease
prion diseases in cattle
- cow brain (feeding cows w/ scrapie)
mad cow disease (bovine spongiform encephalopathy)
prion disease in humans (human variant of mad cow disease)
Creutzfeldt-Jakob disease
prions cause proteins to _____
misfold into infectious forms
Catalysts for chemical reactions in living things
Enzymes
all enzymes are ____ but not all ____ are enzymes
proteins
enzymes catalyze ____ reactions ONLY
sponataneous
A reaction that will proceed without any outside energy (proceed on its own)
spontaneous reaction
the region of an enzyme that attaches to a substrate
Active site of an enzyme
A temporary complex formed when an enzyme binds to its substrate molecule(s).
enzyme-substrate complex
nonprotein enzyme helpers required by some enzymes for activity
Cofactors
organic cofactor
- ex: vitamin B
coenzyme
the enzymatic activity increases with ____ temperature until the enzyme is ___ by heat and inactivated
increasing / denatured
optimal pH for enzymes
pH between 6 and 8
with increasing substrate concentration, the rate of the reaction ___ until the active sites on all enzymes are filled
increases
after an enzyme is denatured, can it become active again?
no
energy currency of the cell
ATP
PEP (phosphoenolpyruvate) has ____ the amount of energy of ATP
twice
why is PEP (molecule in gylcolisis) not the energy currency of ATP?
it costs too much energy to make
- carbon source (amino acids, CO2)
- nitrogen source (amino acids, NH4, N2)
- certain inorganic ions (MG2+, PO4 -3)
- essential metabolites (vitamins)
- water
nutrients that is required by the cell to produce
what bacteria can make every vitamin and nutrients that it needs to function?
E. coli
why is oxygen not a nutrient?
it is not broken down for energy or used in biosynthesis
what is the only reason our body needs oxygen?
as a final electron acceptor in metabolism
converting atmospheric molecular nitrogen into organic nitrogen compounds which can be used by many organisms
nitrogen fixation
is a protein a nutrient for a cell?
no they are too big to get into cells
proteins get nutrients from their breakdown products called
amino acids
how do we measure growth of microorganisms?
measure increase in numbers (exponential growth)
bacteria reproduces by ___ ___
binary fission
- temperature
- pH
- oxygen
conditions for growth
when bacteria are in low temperatures, they grow ____
slowly or not at all
when bacteria are in high temperatures, proteins _____
denature
Aerobic
requires oxygen
Anaerobic
requires lack of oxygen
grow in the presence or absence of oxygen
facultative anaerobes
in the presence of oxygen, all organisms produce ____ which is deadly
superoxide
aerobe organisms produce ___ ___ to get rid of superoxide (O2-)
superoxide dismutase
Counting the number of cells while looking through a microscope
direct microscopic count
what is a disadvantage to using direct microscopic count?
you count all cells including dead ones
method that dilutes cells to singular colonies to make it easier to count
dilution and plating count method
when using the dilution and plating count method, you want to measure an agar plate with less than ___ colonies but more then ___ colonies
300 / 30
in the dilution and plating count method, individual colonies arose from ___ ___
1 cell
most convenient counting method that uses a spectrophotometer to count cells
Turbidity measurements
in the dilution and plating count method, aerobic bacteria are found ____ the agar and anaerobic bacteria are found ____ the agar
on top of / inside
in turbidity measurements, the more bacteria that are present the ____ percentage of light
lower
lag phase, log phase, stationary phase, death phase
Bacterial growth curve phases
phase of a “flat” period of adjustment, enlargement; little growth
lag phase
The period of exponential growth of bacterial population.
log phase
phase in which a period of equilibrium occurs ; microbial deaths balance production of new cells
stationary phase
phase in which population is decreasing at a logarithmic rate
death phase
sum of all chemical reactions in a cell
Metabolism
about _____ metabolic reactions in a cell are POSSIBLE
1000-2000
Metabolic pathways that break down molecules, releasing energy.
Catabolism
Metabolic pathways that construct molecules, requiring energy.
Anabolism
any chemical change in which one species is oxidized (loses electrons) and another species is reduced (gains electrons); also called redox reaction
oxidation-reduction reaction
oxidized
loses electrons
reduced
gains electrons
in biological x, what is typically removed from an organic molecule?
H atoms
the key to all metabolism because it carries the energy
electron
obtain energy from chemicals
Chemotrophs
An organism that must consume organic molecules for both energy and carbon.
Chemoheterotrophs
An organism that needs only carbon dioxide as a carbon source but that obtains energy by oxidizing inorganic substances.
Chemoautotrophs
Chemoheterotrophs with oxygen as final electron acceptor are ____
Most animals, fungi, protozoa, many bacteria
Chemoheterotrophs with organic compound as final electron acceptor is ____
fermentative
Chemoheterotrophs with inorganic compound as final electron acceptor is ____
electron transport chain
Organisms that use light as a source of energy to synthesize organic substances.
Phototrophs
Energy from sunlight, carbon from organic compounds
Photoheterotrophs
An organism that harnesses light energy to drive the synthesis of organic compounds from carbon dioxide.
Photoautotrophs
Photoautotrophs that use water to reduce CO2 are ___ ___
oxygenic photosynthesis
Photoautotrophs that do not use water to reduce CO2 are____ ___
anoxygenic photosynthesis
- substrate-level phosphorylation
- oxidative phosphorylation
- photophosphorylation
methods of ATP generation
The formation of ATP by directly transferring a phosphate group to ADP from an intermediate substrate in catabolism.
substrate-level phosphorylation
The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.
oxidative phosphorylation
The process of generating ATP from ADP and phosphate by means of a proton-motive force generated by the thylakoid membrane of the chloroplast during the light reactions of photosynthesis.
Photophosphorylation
the majority of CO2 is produced in the ___ ___
Krebs cycle
every carbon in glucose is oxidized to ____
CO2
respiration can be ____ or ____
aerobic / anaerobic
- final electron acceptor is not present
- organism may be missing enzyme in Krebs cycle
why wouldn’t a molecule go into respiration?
____ is missing an enzyme in the kreb’s cycle which does not allow it to go through respiration
streptococcus
what are the end products of glycolysis?
2 pyruvic acid / 2 NADH / 2 ATP
- glucose enters cell and 2 ATP go in and 2 ADP come out
- Glucose molecule is split into 2 3-carbon molecules (G3P)
- Electrons are transferred to NAD+ to make NADH
- 2 ADP go in and 2 ATP come out
- Produces pyruvic acid
glycolysis steps
final electron acceptor in fermentation
pyruvic acid
- regenerate NAD+
- getting rid of pyruvic acid by converting it to fermentation end products
2 accomplishments of fermentation
the fermentation end product of streptococcus, lactobacillus, and bacillus
lactic acid
the fermentation end product of saccharomyces (yeast)
ethanol and CO2
in 1914, Chaim Weizmann discovered process by which microbes produce
acetone and butanol
important in production of cordite (a smokeless form of gunpowder)
acetone
what molecule has the highest energy in the electron transport chain?
NADH
which molecule has the most amount of energy in metabolism?
glucose
anaerobic respiration has a ____ ____ energy produced than aerobic respiration and fermentation has ____ ___ energy
little less / alot less
where does most of the energy come from in cellular respiration?
proton motive force
1) electrons from NADH
2) electron transport chain (out of the cell with high concentration of H+)
3) H+ on outside of cell go through proton pump and ATP synthase back into the cell
4) ATP is created from ATP synthase
steps of chemiosmosis
most protons are used to make ATP, but some are used to do work directly like …
- bring AA into cell
- force drives the flagella
cyanide binds at _____ and blocks the electron transport chain process and die
cytochrome a3
proteins/ amino acids can enter the cycle at ____, ____, or ___
glycolysis / acetyl CoA / Kreb’s cycle
lipids can enter the cycle at ____ or ___
glycolysis, kreb’s cycle
carbohydrates enters the cycle at ____ and go through entire metabolic pathway
glycolysis
Core metabolic pathway
glycolysis and the kreb’s cycle
core metabolic pathways DOES NOT INCLUDE ____
the electron transport chain
if only ____ glucose in the metabolic pathway, it will be taken out in glycolysis
1
during glycolysis, glucose is _____ and electrons are removed that go to _____ and reduce to ____
oxidized / NAD+ / NADH
during glycolysis, ATP is made through _____
substrate-level phosphorylation
in fermentation, there is ___ ___ ____ and ___ is regenerated by donating electrons to _____ ____ to form end products
no electron acceptor / NAD+ / pyruvic acid
when the final electron acceptor is present, every carbon in glucose is oxidized to ___ in the ____ ___
CO2 / krebs cycle
in kreb’s cycle, ATP is produced during ___ ___ ___ and removes electrons that go to ___ and ____
substrate-level phosphorylation / NADH / FADH2
end products of the kreb’s cycle
CO2 / ATP / NADH / FADH2
electrons in respiration are transferred to electron transport chain by ___ and ____
NADH / FADH2
when O2 is final electron acceptor it is _____ respiration
when sulfate, nitrate, or sulfur is final electron acceptor it is _____ respiration
aerobic / anaerobic
is streptococcus weaker because it produces less energy in fermentation than it would in respiration?
NO
what can happen under anaerobic conditions with a final electron acceptor?
more energy is produced then fermentation but not as much energy as produced in aerobic conditions
proteins that make up the capsid
capsomeres
viral budding has to do with ____ viruses
enveloped
clostridium botulinum produces a toxin because it contains a ___
prophage
prions are ___ ___ proteins
altered brain
enzyme activity ____ ___ at temperatures below and greater than optimal temperature
slows down
Organisms that grow in warm temperatures (37 degrees C)
Mesophiles
E. coli is a _____ while most Archaea are ____
Chemoheterotrophs / chemoautotrophs
one purpose of fermentation is to ____ pyruvic acid
reduce
NAD+ is a ____
coenzyme
fermentation uses an ____ final electron acceptor
organic
E. coli predominantly carries out ___ respiration
aerobic
the fate of pyruvic acid in an organism that uses anaerobic respiration
it is ultimately oxidized in the kreb’s cycle
viral envelopes are derived from the ___ ___ of the host cell
cell membrane
when an animal DNA virus infects a cell DNA replication takes place ___ the host cell
inside
lysogeny sometimes results in the host cell producing ____
toxins
optimal grow temperature in bacterium is most closely related to the optimal temperature for _____
functioning of enzymes
disadvantage of dilution and plate counting method
may not count aerobes buried in the agar
stationary growth phase is achieved because??
cells run out of nutrients and end products build up
when lactic acid is converted into pyruvic acid, NADH is formed through ____
reduction
microorganisms that are relatively deep below the earth’s surface
chemoautotrophs
organisms that eat decaying organic matter
Chemoheterotrophs
streptococcus gets its energy from _____ and ferments ___ ___
glycolysis / lactic acid
phosphorylation is the ____ of a phosphate to a molecule
addition
catabolism involves ___ and ____ reactions
oxidation / reduction
- substrate concentration
- acidity/alkalinity
- temperature
3 factors enzyme activity is influenced by
nitrogen fixation may one day put an end to what?
world hunger
microorganism that prefers a temperature of 20 C and can cause food spoilage at refrigeration temperatures
pyschotroph
oxidation in biological systems typically do what?
removes hydrogen atoms
microorganism that can “eat” sulfur (inorganic compound)
chemoautoroph
majority of organisms on earth and most common type of life
chemoautotrophs
humans and e.coli are ___
chemoheterotrophs
chemiosmosis/proton motive force relies on an ____ ____
intact membrane
some fermenting bacteria can only produce ___ fermentation product
1
the reason we do not use enzymes to convert the lead to gold is that the conversion is not ____
spontaneous
which categories of nutrients includes amino acids?
- essential metabolites
- carbon source
- nitrogen source
Organisms that grow in extremely high temperatures (90 degrees C)
Hyperthermophiles
cold loving bacteria
Psychrophiles
NADH is a coenzyme and electron ____
donor
the COMPLETE oxidation of glucose results in ___
CO2
The energy to drive protons out through the bacterial cell membrane comes from ____
electrons
the negative effects of viruses on an animal host are usually associated with what 2 things?
Effects of the immune system and/or cell lysis following replication
organism that can use the Kreb’s cycle and can make fermentation products
facultative anaerobes
which bacterium made Chase Weizmann famous?
Clostridium
which types of phosphorylation require electron transport chains?
oxidative phosphorylation / photophosphorylation
what organism can respire aerobically and anaerobically and carry out fermentation?
E. coli
lactic acid converting to pyruvic acid is a _____ reaction
reduction
