exam 2 Flashcards
viruses
not considered cells, not considered to be alive
characteristics of viruses
obligate intracellular parasites, non living, only purpose is to make more viruses
what is the purpose of viruses?
to make more viruses
why are viruses not considered living?
not cellular, can only replicate inside of a host cell, no ATP generating system, no ribosomes, only contain ONE nucleic acid, no metabolism
what are viruses made of?
protein coat, nucleic acid
protein coat
made of capsomeres, protects the nucleic acid, responsible for shape
nucleic acid
“heart” of the virus, either DNA or RNA, not both
do all viruses have an envelope?
only some, but they all have a nucleic acid and protein coat
enveloped viruses
usually have spike proteins, extra “coat” around the capsid
virus specificity (3 types)
animal viruses, plant viruses, bacterial viruses
how can we classify viruses?
size, shape, enveloped or not, type of nucleic acid, specificity
what is the purpose of viruses
the one purpose is to replicate
how do viruses enter in to host cells?
the viral envelope or capsid fuses with the plasma membrane
viral budding
NOT THE SAME as yeast budding, the viral capsid “pinches” off with the plasma membrane of the host cell
lysogenic conversion
imparting a new characteristic to lysogenic cell from the prophage in the host cell
what is an oncogenic virus?
a cancer causing virus; the virus will enter into the body and change genetic material
what are ways to control viral infections
vaccination, anti viral medication (not antibiotics)
viroid
“naked” RNA, no protein coat, this is NOT a virus
example: potato spindle tuber disease
prions
infectious protein, not a virus and not a viroid
prion diseases (5)
scrapie, kuru, chronic wasting disease, mad cow disease, creutzfeldt Jakob disease
what is mad cow disease scientific name?
bovine spongiform encephalopathy
apply enzymatic activity to the reaction of lactose to glucose and galactose
if we were to put lactose in water, it would take over a year to break down, with an enzyme, reaction time is sped up
ribozymes
catalytic RNA
can enzymes catalyze all reactions
no, they can catalyze spontaneous reactions ONLY
are all enzymes proteins
yes, but not all proteins are enzymes
what is the purpose of a cofactor
to “help” the enzyme bind to the substrate
what is the difference between a cofactor and a coenzyme?
a cofactor is inorganic, a coenzyme is organic (hydrocarbon)
is a coenzyme a protein?
no
what 3 factors affect enzymatic activity?
temperature, pH, substrate concentration
how does enzyme concentration affect activity?
it doesn’t, only substrate concentration does
denaturation of a protein
enzyme will unfold and not come back together if conditions are too extreme (ex: pH or temp)
what is the energy currency of the cell?
ATP
why doesn’t the body use PEP/pyruvate?
it has twice the energy but it costs too much energy to make it, energy currency must be intermediate
what nutrients are required by the cell?
carbon source, nitrogen source, certain inorganic ions, essential metabolites, water
carbon sources
carbohydrates, amino acids, CO2
nitrogen sources
amino acids, NH4, N2
inorganic ion sources
Mg2+, PO43-
why isn’t oxygen considered a nutrient?
it is not broken down for energy, it only serves at the final electron acceptor
nitrogen fixation
some microorganisms can convert atmospheric molecular nitrogen into organic nitrogen
is protein a nutrient for a cell?
NO, but amino acids are, proteins are too large to get in to the cells
how do we measure growth of microorganisms?
measure increase in numbers
is binary fission the same thing as mitosis?
no (no nucleus)
what are the three conditions for growth of a microorganism
temperature, pH, oxygen
how are optimal conditions for growth and enzyme activity related
an organism will grow well if its enzymes are functioning well
aerobic
requires oxygen
anaerobic
requires lack of oxygen
what do all organisms produce in the presence of oxygen?
superoxide, it is deadly, organisms that can survive produce superoxide dismutase
direct microscope count
measures growth by counting individual cells
dilution and plating
counts by multiplying by dilution factor
what is metabolism?
sum of all chemical reactions in a cell
catabolism
break down
anabolism
build up
what is biological oxidation?
when electrons and HYDROGEN atoms are removed
what is substrate level phosphorylation (reaction)
C-C-C-P + ADP –> C-C-C + ATP
what kind of respiration does streptococcus perform?
it is missing an enzyme, so it can only ferment (anaerobic)
in what events is ATP produced by substrate level phosphorylation?
in glycolysis and Krebs cycle
what are the 2 products of glycolysis?
pyruvate (pyruvic acid) and NADH
chaim weizmann
discovered process by which microbes produced acetone and butanol (fermentation)
what kind of reaction is the ETC
oxidation reduction
how does chemiosmosis lead to ATP synthesis?
as electrons lose their energy, they force protons to the outside, they get back in through ATP synthase, the force is the energy that joins ADP to Pi
how does cyanide kill us
it binds and interferes with electron transport
what are the core pathways?
Glycolysis and the Kreb’s cycle
what do the core pathways provide
the building blocks for anabolism of nucleic acids, proteins and other nutrients
the core pathways are critical for…
catabolism and anabolism
