Shared Flashcard Set

Details

Molecular cell biology
n/a
265
Biology
Undergraduate 3
02/16/2013
Click here to study/print these flashcards.

Create your own flash cards! Sign up here.

Additional Biology Flashcards

 

 

Cards

Term
What determines the rate of a reaction?
 Definition
Initial concentration of reactants.
Term
What is chemical equilibrium?
 Definition
the forward and reverse rates of reactions are happening at the same rate. There is no change in concentration of reactant and products.
Term
as a reaction proceeds, why does the rate of the forward reaction decrease?
 Definition
because the rate of the reactant decreases.
Term
How can you increase the rate of a reaction?
 Definition
Add a catalyst.
Term
Give the formula for Keq.
 Definition
Keq = ([product A]^a*[product B]^b)/([reactant C]^c*[reactant D]^d)

-[] is concentration
-exponent is the amount of molecules in the reaction.
Term
what does the Keq tell you?
 Definition
Which will be favored: products or reactants.
Term
when will you not reach equilibrium in the cell?
 Definition
when you reach a steady state instead of an equilibrium.
Term
what is a steady state?
 Definition
When one reactant creates a product which is then used as a substrate to create another product. In steady state the forward reaction is faster.
Term
How can you calculate dissociation constant?
 Definition
Kd = [A][B]/[AB]
Term
Your dissociation constant is really small, what does this say about the extent to which a protein is bound to DNA?
 Definition
The protein is bound very tightly to DNA.
Term
Your dissociation constant is very large, what does this tell you about the extent to which a protein is bound to DNA?
 Definition
The protein is not bound very tightly to DNA.
Term
Sodium Hydroxide has a pH of 14. hydrochloric acid has a pH of 0.which one has a higher concentration of H+ atoms? by how much?
 Definition
Hydrochloric acid has a 10^14 fold higher concentration of H+ ions.
Term
are bases H+ acceptors or H+ donors? Bonus: what is this definition of a base called?
 Definition
Bases are proton acceptors. Bronstead-Lowrey bases.
Term
are acids H+ acceptors or H+ donors? Bonus: what is this definition of an acid called?
 Definition
Acids are H+ donors. Bronstead-Lowrey acids.
Term
In an exergonic reaction the delta G for the products will _______ with respect to the reactants.
 Definition
decrease
Term
In an endergonic reaction the delta G of the products will ______ with respect to the reactants.
 Definition
Increase
Term
In an exergonic reaction the formation of products is ______.
 Definition
favored.
Term
in an endergonic reaction the formation of products is ______.
 Definition
not favored.
Term
what kind of reaction (endergonic or exergonic) will happen spontaneously? why?
 Definition
exergonic. because no energy must enter the system for the reaction to take place.
Term
what does an enzyme do?
 Definition
lowers the activation energy (AKA the delta G of the transition state)
Term
the ______ of the _______ of ATP releases free energy to drive many cellular processes.
 Definition
Hydrolysis of the phosphoanhydride bond...
Term
the conversion of succinate to fumarate is a red-ox reaction. when succinate is converted to fumarate, succinate is _______ and fumarate is _______.
 Definition
Succinate is oxidized.
Fumarate is reduced.
Term
What four things are attached to the alpha carbon of an amino acid?
 Definition
1) a hydrogen
2) an amino (NH3+)
3) a carboxyl (COO-)
4) an R group (Hydrocarbons)
Term
which is more hydrophobic: an amino acid with a CH3 R group (alanine) or a CH(CH3)2 R group (Valine)?
 Definition
Valine - more hydrocarbons = more hydrophobic.
Term
What is the N-terminus of a polypeptide chain?
 Definition
The end of a polypeptide chain containing the amino group (NH3+)
Term
how does a peptide bond form?
 Definition
The carboxyl (COO-) of one amino acid and the amino end (NH3+) of another amino acid react via a dehydration reaction (H2O is expelled).
Term
What is the C-terminus of an amino acid?
 Definition
The end of an amino acid that contains the carboxyl group (COO-).
Term
You are analyzing the primary structure of a polypeptide chain. What end would you start? where would you end?
 Definition
You would start at the N-terminus and end at the C-terminus.
Term
what is the directionality of an amino acid?
 Definition
N-terminus to the C-terminus
Term
What is Edman degradation?
 Definition
an early method for figuring out the structure of a polypeptide chain. You label a residue then cleave it with an acid and run a liquid chromatography and repeat with another amino acid until you have the entire structure.
Term
what is a residue?
 Definition
An amino acid that has undergone dehydration synthesis. (an amino acid in a polypeptide chain)
Term
what do we do now so we don't have to do the laborious Edman degradation?
 Definition
We sequence the genome then look at the gene sequence to figure out the amino acid sequence of the proteins.

We also use mass spec to find the molecular mass of the peptides in the protein.
Term
How do you do a mass spec of a protein?
 Definition
you digest the protein and you take a mass spec of the several peptides. you then determine the mass of these peptides and you get the peptide mass fingerprint. You can then search the database to find the data that matches your fingerprint.
Term
How can you directly sequence the protein?
 Definition
Use MSMS.
Term
What causes sickle cell anemia?
 Definition
a mutation in just one amino acid of the hemoglobin protein.
Term
why is sickle cell anemia bad? why is it good?
 Definition
Sickle cell anemia causes RBC's to clog up small blood vessels causing severe pain called crysis.

SCA puts people at an evolutionary advantage because it gives them a resistance to malaria.
Term
Linus Pauling and Robert Corey found that polypeptide chains exist in secondary structures that maximize _____.
 Definition
hydrogen bonding
Term
what is the alpha helix?
 Definition
The backbone of the polypeptide is a spiral structure in which the carbonyl oxygen bonds with the H-atom on the amino acid 4 residues away.
Term
What causes alpha-helices?
 Definition
hydrogen bonding of the carbonyl oxygen to an amino acid 4 residues away.
Term
in an alpha helix the ______ is inside and the _____ project outward.
 Definition
peptide backbone is inside
R group is projecting outward.
Term
Give 3 examples of proteins that contain alpha helices
 Definition
keratin, myoglobin, hemoglobin.
Term
in _______ the hydrogen bonds are taking place BETWEEN adjacent strands. In the ______ the hydrogen bonds are taking place WITHIN adjacent strands
 Definition
B-pleated sheets

Alpha helix
Term
What is an example of proteins in fish that has a lot of B-pleated sheets?
 Definition
circulating antifreeze proteins.
Term
about what percent of a protein is alpha helices and beta pleated sheets?
 Definition
60%
Term
how many residues are involved in a beta turn?
 Definition
4
Term
Alpha helices, beta pleated sheets, and beta turns are all part of the ______ structure of a protein
 Definition
secondary
Term
what does the beta turn do the polypeptide backbone?
 Definition
Changes the directionality.
Term
How do they determine the tertiary structure of a protein?
 Definition
X-ray crystallography
Term
What is the tertiary structure of a protein?
 Definition
The conformation of the entire protein.
Term
Covalent or noncovalent?
primary structure of a protien
Secondary structure of a protein
Tertiary structure of a protein
 Definition
primary - covalent
secondary - noncovalent (only h-bonding)
tertiary - noncovalent.
Term
what three bonding types cause the tertiary structure?
 Definition
Ionic, hydrogen, van der waals
Term
in the tertiary structure, functionally distinct modules that fold independently of one another are called ________.
 Definition
Domains
Term
what 3 protein folding motifs did we talk about?
 Definition
Coiled-coil motif, zinc-finger motif, EFhand/Helix-loop-helix motif.
Term
what are the three main classes of proteins?
 Definition
Structural
Functional
Topographical
Term
The protein tertiary structure consists of domains that can either be ______ or ______.
 Definition
Structural or functional
Term
T/F The tertiary structure is static
 Definition
False, small randome changes in the presence or absence of bonds can change the structure.
Term
proteins that are made up of more than one polypeptide chain are called ________.
 Definition
Multimeric proteins.
Term
a multimeric protein with two of the same subunits (polypeptide chains) is called ________.
 Definition
a homodimer
Term
a protein with two different subunits, four subunits total is called ______.
 Definition
a heterotetradimer
Term
an example of a heterotetradimer is _______.
 Definition
hemoglobin
Term
a protein can only have a quaternary structure if it is a ________ protein.
 Definition
multimeric
Term
What is the highest level of protein structure?
 Definition
The association of proteins into macromolecular assemblages.
Term
What is an example of a macromolecular assemblage?
 Definition
The conversion of general transcription factors and a mediator complex into a transcription preinitiation complex by RNA polymerase.
Term
Many proteins exist in _________ where different proteins with different functions physically associate.
 Definition
multiprotein complexes
Term
interacting proteins may have ________ where one molecule fits into the pocket of another.
 Definition
complementary surfaces
Term
a protein scaffold will ...
 Definition
Bring proteins together into ordered arrays
Term
transport proteins ....
 Definition
regulate the flow of ions and molecules across a membrane.
Term
regulatory proteins ....
 Definition
signals, senses and switches to control the activity of cells by altering the function of other proteins and genes.
Term
signaling proteins are...
 Definition
cell surface receptors that transmit extracellular membrane signals to the intracellular matrix
Term
motor proteins ...
 Definition
move other proteins in organelles and cells.
Term
why aren't b-pleated sheets considered tertiary structure?
 Definition
the polypeptide chains in the sheets are only 4-8 residues long.
Term
mammalian proteins tend to have ______ domains than a fruit fly.
 Definition
more
Term
similarities in domains across species indicate...
 Definition
a common evolutionary origin.
Term
what does acetylcholine esterase do?
 Definition
degrades acetylcholine left behind after transmission of an impulse from one neurone to the next.
Term
pyruvate dehydrogenase consists of ______ polypeptide chains and ____ different enzymes that catalyze a series of reactions connecting glycolysis and TCA cycle.
 Definition
60 different polypeptide chains
3 different enzymes.
Term
what is the advantage to linking associated enzymes in multiprotein complexes?
 Definition
the substrate from one enzyme can move to the next without being diluted in the cytosol.
Term
what do molecular chaperones do?
 Definition
bind and destabilize unfolded proteins. this prevents proteins from forming aggregates.
Term
are the major anabolic and catabolic pathways interconnected?
 Definition
Yes.
Term
what are the two functions of the catabolic pathway?
 Definition
To provide raw materials
to provide chemical energy
Term
T/F the cell can break down more complex molecules to make simpler molecules or it can put together simple molecules to make complex molecules.
 Definition
True
Term
what happens in an red-ox reaction?
 Definition
one molecule is oxidized and loses it's electrons, one molecule is reduced and gains the electrons lost from the oxidized molecule.
Term
what are the three classes of macromolecules?
 Definition
Proteins, lipids, polysaccharides.
Term
why is methane the most reduced state while carbon dioxide is the most oxidized state?
 Definition
because in methane the carbon is the most electronegative atom which means it gets the highest share of electrons. In CO2 the oxygens take most of the electrons because they are more electroneg.
Term
why is methane the simple compound with the potential to produce the most energy?
 Definition
Because it has 4 hydrogens with one attached to a highly electronegative oxygen. methane has 4 hydrogens but no oxygen.
Term
explain why C6H1206 + 602 --> 6CO2 + 6H2O is a red-ox reaction.
 Definition
The glucose is losing hydrogens and electrons when it is converted to CO2 and the O2 is gaining hydrogens and electrons to become H2O so it is being reduced.
Term
is energy released when bonds are formed or broken?
 Definition
formed.
Term
do cells obtain energy from oxidizing or reducing macromolecules?
 Definition
oxidizing.
Term
how does digestion take place inside of the cell?
 Definition
the lysosome breaks down macromolecules into subunits.
Term
Without oxygen, your muscle cells will breakdown _______ to produce ______ which then undergoes _______.
 Definition
glucose
lactic acid
lactic acid fermentation
Term
T/F ATP, pyruvic acid, and NADH are produced in glycolysis.
 Definition
true.
Term
The main product of glycolysis is _____.
 Definition
2 pyruvates
Term
in what stage of cellular respiration are most of the high energy electrons stripped away from organic compounds and stored in NAD and FAD?
 Definition
The citric acid cycle.
Term
What is the net gain from one molecule of glucose in glycolysis?
 Definition
2 (3C) Pyruvate, 2 ATP, and 2 NADH
Term
explain in detail the energy investment phase of glycolysis.
 Definition
one glucose molecule is turned into glucose 6 phosphate by the enzyme hexokinase which transfers a phosphate from the ATP to glucose. This makes G6P. G6P is turned into Fructose 6-phosphate by phosphoglucose isomerase (not important for exam). Fructose 6-phosphate is phosphorylated and turned into fructose 1,6-bisphosphate by phosphofructokinase using one ATP.
Term
what two enzymes in glycolysis are involved in phosphorylation?
 Definition
Hexokinase and phosphofructokinase
Term
what does kinase imply?
 Definition
phosphorylaation
Term
what is phosphorylation?
 Definition
transfer of phosphate groups from high energy donor molecules like ATP to specific substrates.
Term
what does the enzyme phosphofructokinase do?
 Definition
phosphorylates Fructose 6-phosphate to make Fructose 1,6-bisphosphate.
Term
what two three carbon molecules are Fructose 1,6-bisphosphate broken down into and by why enzyme.
 Definition
Fructose 1,6-bisphosphate is broken down into Glyceraldehyde 3-phosphate and dihydroxyacetone phosphate by aldolase.
Term
why does hexokinase have to expend ATP converting glucose into glucose 6-phosphate?
 Definition
first, if the glucose is not phosphorylated, it can not do the subsequent reactions. Second, it lowers cytosolic glucose which causes continued influx of glucose into the cell.
Term
what does the enzyme triose phosphate isomerase do?
 Definition
converts dihydroxyacetone to glyceraldehyde 3-phosphate
Term
what two important things does the enzyme Glyceraldehyde phosphate dehydrogenase do in glycolysis?
 Definition
1) adds a phosphate to turn G3P into 1,3-phosphoglycerate
2) strips the hydrogen off of G3P and gives the two electrons to NAD+
Term
To what group in NAD+ is the hydrogen added?
 Definition
to the nicatinamide group
Term
What does NAD+ stand for?
 Definition
Nicotinamide Adenine Dinuncleotide. It has two ribose groups. One ribose group has a nicotinamide and the other has an adenine.
Term
what is the principal source of ATP in aerobic organisms?
 Definition
Glycolysis
Term
considering the enzyme phosphofructo kinase-1 is an enzyme that strips a phosphate off of ATP and phosphorylates Fructose 6-phosphate to make fructose 1,6-biphosphate in glycolysis, and that ATP allosterically inhibits the phosphofructo kinase-1 enzyme, explain why the presence of ATP does not stop glycolysis.
 Definition
The active site is more reactive than the allosteric site so in low concentrations the ATP will bind the the active site of the phosphofructo kinase enzyme, but in high concentrations the ATP will inhibit the enzyme.
Term
what inhibits pyruvate kinase?
 Definition
ATP
Term
what is hexokinase inhibited by?
 Definition
It's product, Glucose 6-phosphate.
Term
how does the feed forward reaction work in glycolysis?
 Definition
The creation of Fructose 6-phosphate by phosphoglucose isomerase accelerates the formation of fructose 2,6 biphosphate which is an allosteric activator of phosphofructo kinase-1. So the abundance of this metabolite, fructose 6-phosphate will induce the acceleration of it's own metabolism into fructose 1,6-biphosphate.
Term
when in carbohydrate starvation, what happens in glycolysis?
 Definition
Glycogen is converted directly to glucose 6-phosphate. Glucose 6-phosphate from glycogen is then turned into glucose by phosphotase.
Term
how does insulin and glucagon control blood glucose?
 Definition
Insulin is released by the pancreas when blood glucose levels are high to induce phosphofructo kinase-2 activity and stimulate glycolysis
Term
what happens to pyruvate in the absence of oxygen?
 Definition
NADH donates its electrons to pyruvate to make lactic acid.
Term
what enzyme helps NADH put a hydrogen on pyruvate to make lactic acid?
 Definition
Lactate dehydrogenase
Term
how does the liver turn the lactate back into glucose?
 Definition
It does glycolysis and lactic acid fermentation in reverse, costing 6 ATP.
Term
Does the RBC have mitochondria?
 Definition
No it uses glycolysis exclusively to create energy.
Term
why does the RBC need energy?
 Definition
to maintain electrochemical and ion gradients across it's membrane.
Term
do mitochondria have ribosomes?
 Definition
Yes
Term
describe the endosymbiont theory for mitochondria in one sentence.
 Definition
The eukaryotic cell arose when a glycolytic protoeukaryotic cell engulfed a oxidative bacterium and they formed a symbiotic relationship.
Term
what is a missense mutation?
 Definition
a point mutation of one nucleotide that causes a different amino acid to be coded for.
Term
what is a nonsense mutation?
 Definition
A point mutation of one nucleotide that causes a premature stop codon.
Term
what is a silent mutation?
 Definition
a point mutation of one nucleotide that causes no change in amino acid arrangement.
Term
explain how people get Leber's hereditary optic neuropathy (LHON).
 Definition
it is inherited from the mother and causes sudden onset blindless resulting from a missense mutation in the mitochondrial DNA.
Term
most mitochondrial disorders result from ______
 Definition
mutations in the mitochondrial DNA.
Term
why is mtDNA more susceptable to genetic mutations?
 Definition
It does not have access to DNA repair systems found in nuclear DNA. 10X the mutation rate for DNA in mtDNA.
Term
why does the mitochondria affect the nervous system? give an example of a nervous system disease caused by mitochondrial dysfunction.
 Definition
Mitochondrial mutations accumulate in cells that are in our body for long periods of time. Neurons are one of these cells. Parkinson's disease is associated with a degradation of mitochondrial function.
Term
T/F mitochondrial function probably declines with age.
 Definition
TRUE
Term
what experiment showed that mitochondrial mutations may cause aging?
 Definition
One mouse that harbors a genetic alteration that allow its mitochondria to accumulate mutations at a rate of 3-8x the rate of normal mice. After 9 months it showed signs of premature aging in relation to its counterpart.
Term
what evidence is there that mtDNA dysfunction may lead to aging in humans?
 Definition
PCR of young mtDNA shows little variation. PCR of old mtDNA shows a high amount of variation and rearrangements indicating DNA mutation.
Term
if a mitochondria has a lot of cristae, what can you conclude?
 Definition
That it has an increased ability to make ATP due to the increased surface area of the inner membrane.
Term
T/F Mitochondria of the heart and skeletal muscles have three times less cristae as the liver cells.
 Definition
False, skeletal and heart muscles have 3 times more mitochondria than the liver cells.
Term
where does the citric acid or Krebs cycle take place?
 Definition
In the inner mitochondrial membrane space.
Term
what are the basic properties of cells. (9)
 Definition
They:
1. have a genetic program
2. are organized
3. can reproduce themselves
4. can acquire and use energy
5. can carry out metabolism
6. engage in mechanical activities
7. respond to the world around them
8. self regulate.
9. have evolved to take on more and more specialized functions as necessary
Term
do bacteria have a nucleus?
 Definition
No they just have a nucleoid region.
Term
What is the bacterial cell wall made of?
 Definition
Peptidoglycan
Term
what 4 organelles are common to eukaryotes and prokaryote?
 Definition
Nucleus
Endoplasmic Reticulum
Ribosomes
Vacuoles
Term
how are prokaryotes and eukaryotes similar other than some shared organelles?
 Definition
-plasma membrane is of similar construction
-genetic information is encoded in DNA using identical genetic code
-similar mechanisms for the transcription and translation of genetic material, similar ribosomes.
-same metabolic pathways (TCA and glycolysis)
-similar apparatus for the conservation of chemical energy as ATP (in plasma membrane of prokaryotes, mitochondria in eukaryotes)
-similar mechanisms of photosynthesis
-similar mechanisms for synthesizing and inserting membrane proteins.
-proteasomes are of similar construction.
Term
where in the cell are fatty acids hydrolyzed to acetyl-CoA by beta oxidation enzymes?
 Definition
in the peroxisomes (or gylcoxisome in seedlings).
Term
what is an endosome and what does it do?
 Definition
The early endosome is a conglomeration of endosomes formed by phagocytosis. The early endosome can either be recycled or can become a late endosome which may become a lysosome.
Term
which protein will coat vesicles in a polyhedral lattice so molecules can safely be transported throughout and between cells.
 Definition
Clathrin
Term
which protein is important in identifying specific cellular cargo to be engulfed?
 Definition
Adaptin
Term
what protein pinches of the endosome being formed from the membrane?
 Definition
Dynamin
Term
do prokaryotic cells have complex flagella and cilia?
 Definition
No.
Term
T/F prokaryotes have no cellular membrane
 Definition
True they only have a nucleoid region.
Term
T/F Prokaryotes have a cytoskeletal system with microfilaments, intermediate filaments, and microtubules.
 Definition
False.
Term
Can prokaryotes ingest materials by phagocytosis?
 Definition
No.
Term
Which has a larger genome prokaryotes or eukaryotes?
 Definition
eukaryotes.
Term
T/F Bacterial DNA is usually circular.
 Definition
True.
Term
what 3 layers are on the outside of prokaryotic cells?
 Definition
Plasma membrane, cell wall, capsule.
Term
T/F Eukaryotic DNA is circular.
 Definition
False, Eukaryotic DNA is linear.
Term
What is chromatin?
 Definition
DNA and histone proteins wrapped up to form chromatin fibers.
Term
what are two organelles that plant cells have that animal cells do not have?
 Definition
vacuoles and chloroplasts.
Term
T/F Bacteria can exchange genetic material with eachother
 Definition
True
Term
What is it called when a small piece of DNA is passed from one bacteria to another?
 Definition
Conjugation
Term
how do bacteria move through their environment?
 Definition
using flagella - thin protein filaments.
Term
Are bacterial and eukaryotic flagella the same thing?
 Definition
No eukaryotic flagella are much more complex.
Term
what are the two types of prokaryotes?
 Definition
Archea and Eubacteria.
Term
which lineage is probably more closely related to eukaryotes: Archea or Bacteria? why do scientist think this?
 Definition
Archea. They code for homologous histone proteins and also have similar ribosomes.
Term
How did they think the prokaryote became the eukaryote before the endosymbiont theory was postulated by Lynn Margulis?
 Definition
They thought the prokaryotic cell got gradually more complex.
Term
how did Carl Woese give evidence for the endosymbiont theory?
 Definition
He compared nucleotide sequences of RNA molecules from the ribosomes of different organisms. He found that the 16S sequence from the chloroplasts of a Euglena was more similar to the 16S sequence from cyanobacteria and eukaryotes.
Term
who figured out the tree of life showing archea closer to eukaryotes than bacteria?
 Definition
Carl Woese.
Term
what is an example of a unicellular eukaryote?
 Definition
Vorticella
Term
Stem cells show two essential properties, what are they?
 Definition
1) stem cells can self renew
2) stem cells can produce multiple different cells.
Term
What are the two types of stem cells? What term describes each of these?
 Definition
Adult stem cells - pluripotent - can give rise to many cell types but not all.

Embryonic stem cells - totipotent - can give rise to all cell types.
Term
T/F Both RBC's and WBC's originated with the same type of stem cell.
 Definition
True.
Term
When do embryonic stem cells probably stop being totipotent?
 Definition
After the 8 cell stage.
Term
T/F the inner cell mass of the 64 cell stage is totipotent
 Definition
True
Term
What is therapeutic cloning?
 Definition
You take a somatic cell from the patient then fuse it with an enucleated oocyte, let it develop into a blastocyct then culture it into the tissue the patient needs and transplant.
Term
What are obligate intracellular parasites?
 Definition
Viruses that can only replicate inside a host's cell.
Term
what kind of virus causes colds, AIDS, smallpox, influenza, measels, ebola, and hanta?
 Definition
Obligate intracellular parasites
Term
What is Koch's Postulate
 Definition
A disease could be attributed to a particular organism if:
-the microorganism could always be found in individuals with the disease
- the microorganism from the host could be grown in a pure culture
- a sample of the culture can produce the disease if injected into a new healthy host
- the microorganism can be reisolated/recovered from the diseased animal and grown in pure form again.
Term
what can Koch's postulate not be applied to?
 Definition
Viral diseases. They can not grow in a culture.
Term
Can viruses be seen with a light microscope?
 Definition
NO
Term
How did Dmitri Iwanowski discover viruses?
 Definition
He took the sap from a tobacco plant infected with tobacco mosaic virus and infect another plant with it even if the sap showed no signs of bacteria under light microscope. He filtered the sap through pores smaller than the smallest known bacterium and concluded that there must be an even smaller pathogen - viruses.
Term
what did walter reed do and how did he do it?
 Definition
Walter reed studied yellow fever in 1900 during the spanish american war. He used mice to find that mosquitoes are likely causing yellow fever.
Term
Who was Freidrich Loeffler?
 Definition
A researcher who did experiments similar to Dmitri Iwanowsky to find out that an infectious viron was causing hoof and mouth disease in cattle. He proved that the virus could affect animals as well as plants.
Term
What did Frederick Twort discover?
 Definition
Viruses that infected bacteria - Bacteriophages.
Term
What did Ernst Ruska do?
 Definition
Pioneered the development of the electron microscope in the 1930's
Term
What did Max Theiler do?
 Definition
Pioneered the growth of viruses in chicken eggs - this is how many of our vaccines are generated today.
Term
Genetic material in bacteria is surrounded by a protein coat called the ______
 Definition
capsid.
Term
T/F Viruses only have single stranded DNA
 Definition
False, they can have double stranded or single stranded DNA or RNA.
Term
What is an adenovirus?
 Definition
a hexagonal shaped floating virus with receptors on it's edges.
Term
The nucleic acid + the capsid is called...
 Definition
The nucleocapsid.
Term
What two shapes can a virus be?
 Definition
Icosahedral or helical.
Term
what two ways can a virus leave the host cell?
 Definition
Lysis or budding.
Term
What happens in the lytic cycle?
 Definition
The virus inserts it's DNA, the phage DNA circulates then hijacks cellular machinery to synthesize and assemble new viruses then the cell is lysed and the virons are released.
Term
What happens in the lysogenic cycle?
 Definition
The viral DNA is injected, it circulates then inserts itself into the cell genome and become a prophage. The cell then replicates transmitting the prophage to daughter cells.
Term
if a virus incorporates its DNA into the host cell it is a ______.
 Definition
Provirus
Term
what is an example of a provirus that goes through the lysogenic cycle?
 Definition
HIV
Term
What three things can proviruses do?
 Definition
1. they can behave normally until it is exposed to a stimulus like UV light.
2. They can bud off new progeny (HIV does this)
3. They can become malignant and unable to control their growth. (Tumor viruses)
Term
why do some viruses that leave by exocytosis have the ability to be encytosed by other cells?
 Definition
Because they have that cells glycoproteins (proteins with oligosaccharides) that function in cell to cell recognition.
Term
does the HIV virus bud or lyse?
 Definition
it buds.
Term
what are the infected cells in the influenza virus?
 Definition
The epithelium of the respiratory tract.
Term
What is the difference betweenn influenza A, B, and C?
 Definition
Influenza C infects pigs, humans, and dogs and only causes very mild infections.
Influenza B is the standard seasonal flu and is mostly found in humans. Can cause localized outbreaks - epidemics

Influenza A is usually found in non humans such as ducks, chickens and horses but can occasionally infect humans. When it does it can lead to epidemics and even pandemics because it is not expected.
Term
T/F influenza caries its genome as ssRNA.
 Definition
TRUE
Term
how many RNA sequences does influenza A and B have?
 Definition
8
Term
what two coat proteins cause influenza to have the ability to infect again after you get a vaccination?
 Definition
HA and NA
HA = hemaglutinin
NA = Neuraminidase
Term
What is antigenic drift?
 Definition
The antibodies that block a virus attack the hemaglutanin or neuroaminidase but the ssRNA in the influenza virus mutates very quickly so the NA or HA will eventually be unrecognizable to the host cell. This will cause antigenic drift.
Term
what is antigenic shift? explain how antigenic shift can be caused by subunit mixing.
 Definition
Antigenic shift is the emergence of an influenza type that didn't usually infect humans. Subunit mixing is a mixing of two different strains of the flu in an intermediate host.
Term
antigenic shift is what causes ________.
 Definition
Pandemics
Term
how do we know anything about viruses?
 Definition
We used fluorescent tags to watch viruses under a microscope.
Term
We must get a seasonal flu shot thanks to _______.
 Definition
antigenic drift
Term
Pandemics occur because of __________.
 Definition
Antigenic shift
Term
T/F viruses can be good.
 Definition
True - used in research and can kill some harmful insects and bacteria.
Term
what is gene therapy?
 Definition
the use of viruses to inject and incorporate certain genes into the host cell that are beneficial.
Term
T/F the plasma membrane can be observed with a light microscope.
 Definition
F - only 5-10nm thick must be observed with an electron microscope.
Term
what are the 7 things that plasma membranes do.
 Definition
1. compartmentalize
2. Scaffolding - a framework for the cell.
3. Selectively permeable barrier
4. Transporting solutes
5. responds to external stimuli
6. intercellular interaction
7. energy transduction - chemical energy to ATP
Term
the plasma membrane is composed of:
 Definition
Lipids, carbohydrates, and proteins.
Term
How did Gorter and Grendel figure out that there must be a lipid bilayer in cells in 1925?
 Definition
They used RBC lipids and water and a movable barrier to compress the lipids. They calculated that the surface area was only 2:1 with respect to red blood cells so there must be another layer.
Term
What did Davson and Danielli propose in 1935?
 Definition
That there are proteins in the plasma membrane.
Term
Who proposed the fluid-mosiac model of the cell membrane in 1972?
 Definition
Singer and Nicholson
Term
what organelles have double membranes?
 Definition
1) nucleus
2) mitochondria
3) chloroplast
Term
Phospholipids contain a hydrophobic carbohydrate tail and a hydrophyllic phosphate head. This makes them ___________.
 Definition
Amphipathic
Term
What are the three main types of lipids?
 Definition
1) phosphoglycerides
2) Sphingolipids
3) Cholesterol
Term
What is the backbone of the phosphoglyceride?
 Definition
A glycerol backbone esterfied to the fatty acid.
Term
what is the term for the water soluble part of a phosphoglyceride?
 Definition
Head group
Term
T/F of the two phosphoglyceride fatty acid chains - one is usually sauturated while the other is unsaturated.
 Definition
True
Term
What are sphingolipids?
 Definition
Spingosine is attached to the fatty acid by its amino group. All is connected to a phosphate and a head group.
Term
what is a glycolipid?
 Definition
A sphingolipid with a carbohydrate attached to its hydroxyl group.
Term
what is a cerebroside?
 Definition
A glycolipid that is a sphingolipid with a simple sugar carbohydrate attached to its OH group.
Term
What is a ganglioside
 Definition
A glycolipid that is a sphingolipid with a cluster of sugars attached to the OH group.
Term
Mice that lack the enzyme that adds the galactose to the ceramide sphingolipid have severe tremors and eventually become paralyzed. Why is this?
 Definition
The Nervous system is rich in glycolipids. They are especially rich in the myelin sheath which is probably why the mouse is having out of control tremors then degradation of the nervous system.
Term
T/F in certain animal cells cholesterol makes up about 50% of the plasma membrane
 Definition
true.
Term
T/F cholesterol is found in most plant and bacterial cells.
 Definition
False most plant cells have none and no bacterial cells have cholesterol.
Term
why does cholesterol interfere with the fluidity of the membrane?
 Definition
Because the rigid ring structures interfere with the movement of the phospholipids.
Term
why aren't there square animal cells?
 Definition
Because that would expose the hydrophobic lipid tails to the extracellular matrix.
Term
do the tails of all phospholipids orient parallel?
 Definition
No some phospholipids have V shaped tails which allows for a bending of the plasma membrane.
Term
T/F membranes are inflexible
 Definition
False.
Term
how do you make a liposome?
 Definition
put a small amount of phospholipids into an aqueous solution.
Term
what are the possible functions of cilia or flagella?
 Definition
Cilia can increase the surface area and allow for greater absorption. Cilia can beat to move fluids through. Flagella can allow for locomotion.
Term
How are liposomes used for research?
 Definition
They can insert membrane proteins, deliver drugs or DNA molecules into the body.
Term
What does PEG do the the liposome?
 Definition
Polyethylene glycol is a hydrophilic polymer that protects the liposome from immune cell. The earliest attempts to use liposomes for research failed because the immune system targeted and destroyed them. PEG makes the liposome a stealthy liposome.
Term
T/F membranes are covalently attached to lipids called glycolipids or proteins called glycoproteins.
 Definition
True
Term
What is it called when a oligosaccharide (glucose, galactose) is attached to a protein?
 Definition
Glycosylation.
Term
what does the attachment of an oligosaccharide to a protein do?
 Definition
helps the cell to interact with the environment.
Term
________ make up the antigens that determine which blood blood type you have
 Definition
carbohydrates
Term
all humans have the enzymes for synthesizing ______ antigen (blood).
 Definition
O
Term
those with type A blood have ______ antigen which adds a _______ to the O antigen.
 Definition
glycosyltransferase

N-acetylgalactosamine
Term
What are the three classes of proteins?
 Definition
1) integral proteins
2) Peripheral proteins
3) lipid anchored proteins
Term
What two ways can a peripheral membrane protein attach to the plasma membrane?
 Definition
1) associate with the membrane by noncovalent bonds
2) associate the the proteins
Term
T/F lipid anchored proteins are covalently bonded to the lipids
 Definition
True.
Term
what functions can an integral membrane protein have?
 Definition
-receptors
-transport channels
-enzymes
-agents that transfer e-
Term
T/F Membrane transport proteins are amphipathic.
 Definition
True.
Term
how did they prove that there were integral proteins?
 Definition
They used freeze fracturing. They froze a cell then fractured it to separate the two layers. They found that on one side there was a protein and on the other side a hole.
Term
If you want to isolate a membrane protein from the membrane should you use a ionic or nonionic detergent?
 Definition
Nonionic detergent because the ionic detergent will denature the protein.
Term
how can you solubilize a peripheral membrane protein?
 Definition
Use concentrated salt solution.
Term
how can you solubilize a GPI-anchored protein?
 Definition
You must use an enzyme called phospholipase which cleaves the inositol containing phospholipids.
Term
what is a GPI-anchored protein?
 Definition
A protein attached to the plasma membrane by an oligosaccharide attached to a phosphatidylinositol.
Term
T/F Long fatty acid tails will make the plasma membrane more fluid
 Definition
False. Short tails increase fluidity of the plasma membrane
Term
T/F Unsaturated Fatty acids make the membrane more fluid.
 Definition
True.
Term
T/F the membrane will be more fluid if you heat up its environment
 Definition
True.
Term
The glycolipids are on the side of the membrane facing the _______.
 Definition
Extracellular space
Term
How do macrophages know that a cell must be dissolved during apoptosis?
 Definition
The phosphatidylserines on the cytosol side of the plasma membrane will switch over to the extracellular side which indicated to the macrophages that the cell should be digested.
Term
What are lipid rafts?
 Definition
Potential areas of concentrated sphingolipids and cholesterol.
Term
what might the lipid rafts do?
 Definition
They might function in microdomains that could participate in signaling.
Term
what is it called when a lipid moves from the ECM monolayer to the cytosolic monolayer?
 Definition
Transverse diffusion (flip-flop)
Term
What is it called when a lipid moves laterally within its leaflet?
 Definition
Lateral shift.
Term
how did they find that proteins could move without being restricted by the plasma membrane?
 Definition
They took a human cell and a mouse cell and labeled the mouse proteins with a green fluorescent tag, and the human proteins with a red fluorescent tag. They then used a virus to make the two cells fuse then saw that the two colors were mixed in the resulting cell.
Term
in what 4 kinds of mobility could a protein have in the cell?
 Definition
- can move freely and randomly
- immobilized
- can move in a directed manner
- free movement but is restricted
Term
what is passive transport?
 Definition
Movement of ions with their concentration gradient. requires no energy. Requires no proteins.
Term
what is active transport?
 Definition
uses energy and proteins to move substances across their concentration gradient
Term
what is facilitated diffusion?
 Definition
substances are allowed to flow with their concentration gradient but a protein gate must be opened first.
Term
What are the 3 types of lipids
 Definition
fatty acids, steroids, phospholipids
Term
Carbohydrate + Protein is called...
 Definition
A glycoprotein.
Term
metal group + protein is called...
 Definition
A metalloprotein
Term
A protein + an organic group is called...
 Definition
A flavoprotein.
Supporting users have an ad free experience!