B/B Practice test review Flashcards
RNA polymerase
deals with transcriptional regulation.
transcribes mRNA from the DNA template
doesn’t have good editing ability.
DNA polymerase
the only enzyme that synthesizes DNA
can make cDNA double stranded
- What is a resting potential? what is a typical value?
- what is hyperpolarization?
- What is depolarization?
- What is repolarization?
- Resting potential is the potential across the membrane. A typical neuron has a resting potential of -60 to -70 millivolts implying that the interior of the cell is negatively charged relative to the outside.
- Hyperpolarization is when the membrane potential becomes more negative
- depolarization is when the membrane potential becomes less negative (more positive) - once threshold is reached, cell can depolarize up to about +30 or +40 mV.
- depolarization and hyperpolarization occur when ion c hannels in the membrane open or close and alter the ability of particular types of ions to enter/exit the cell.
- opening channels to let + ions out or - ions in (ex: K+ exit the cell or letting Cl- into the cell) encourages hyperpolarization. Opening channels that let + ions flow into the cell can cause depolarization (ex: letting in Na+)
- Repolarization is like the “calm down” period after depolarization where the cell is trying to correct itself (ex: when voltage gated potassium channels open, allowing K+ to rush out of the cell which rapidly decreases the membrane potential to bring it back towards its resting state)
what lymphocytes are made upon exposure to viruses and pathogens
both B and T lymphocytes
- humoral immunity
- cell-mediated immunity
- passive immunity
- immunity through fluid (ex: blood)where B cells release antibodies into the bloodstream
- the process that T cells are involved in
- an injection of antibodies to act as a temporary supply and help fight off a disease until a person’s own immune system can start producing antibodies
what will happen if an individual is reinfected with the same virus
the immune system will destroy the pathogen before it has time to cause disease
response to a 2nd infection with the same antigen is much more rapid than the primary response and also requires much less antigen
What are antibpdies produced by?
why is there a latent period in the production of antibodies during the primary response?
How do antigens interact with B cells?
What are antigens?
antibodies are made by the B lymphocytes
the latent period is the time required for lymphocytes to divide and differentiate into plasma membrane cells.
antigens do not infect the B cells but binds to them
Antigens are “identifiers” that are specific to pathogens and help the immune system know what is a threat
what are lymphocytes?
a type of immune system cell that can perform phagocytosis
Which pathways produce NADPH?
Which pathways produce NADH?
NADPH is produced in PPP Pentose phosphate pathway
NADH is produced in glycolysis and TCA
What is the difference between anabolism and catabolism?
Anabolism is biosynthesis. Anabolic reactions require energy. Endergonic. Requires NADPH (reducing agents- things that oxidize).
- example: PPP, gluconeogenesis, FA synthesis
Catabolism is breakdown. Catabolic reactions release energy. Require NAD+
- example: Glycolysis, TCA, ETC & OxPhos, Beta oxidation
Where do the following metabolic processes occur?
- FA synthesis
- TCA
- glycolysis
- Gluconeogenesis
- Pentose Phosphate Pathway
- Beta/FA oxidation
- ETC/Oxphos
- GLYCOgenesis (glycogen formation)
- FAS- cytosol
- TCA- mitochondrial matrix
- Glycolysis- cytosol
- Gluconeogenesis- mitochondrial matrix
- PPP- cytosol
- Beta/FA oxidation- mitochondrial matrix
- ETC/Oxphos- mitochondrial martix (inner membrane/ cristae and intermembrane space)
- GLYCOgenesis- cytosol
What does saponification of linolein (a triacylglycerol with linoleic acid as the FAs) produce?
Saponification yields one glycerol backbone molecule from the TAGs as well as 3 acid salts, in this case 3 linoleic acid salts called potassium linoleate/.
FAs do not remain protonated under basic (saponification) conditions
What is saponification>
a process where TAGs are reacted with sodium or potassium hydroxide (lye) to produce glycerol and a fatty acid salt called “soap” ;)
(Soaps are just salts of fatty acids!)
What is competitive inhibition? Uncompetitive inhibition? Mixed inhibition? Noncompetitive inhibition?
-
competitive: the inhibitor “competes” with the substrate for the enzyme. Only the inhibitior OR the substrate can be bound at a given time.
- NO effect on Vmax but increases Km
-
uncompetitive: binds ONLY to enzyme-substrate complex and NOT to the free enzyme.
- reduces Vmax and Km
-
mixed inhibition: displays behavior of competitive and uncompetitive inhibitors. Binds to both the free enzyme and enzyme-substrate complex but has a higher affinity for one form than the other
- reduce Vmax , can increase or decrease Km
-
noncompetitive: inhibitor doesn’t block the substrate from binding to the active site. Instead, it attaches at another site and blocks the enzyme from doing its job. Both can be bound at the same time.
- like a special case of mixed inhibition
- decreases Vmax but doesn’t change Km1 since it has equal affinity for enzyme and enzyme-substrate complex
what does the graph look like for cooperative binding?
sigmoidal curve. “switch-like” transition from low to high reaction rate as substrate concentration increases
What is competitive inhibition? How does it affect Km and Vmax?
Competitive inhibition is where the inhibitor resembles the substrate and will bind to the enzyme’s active site in order to prevent the substrate from binding there
Km is increased since the affinity of the substrates has decreased because of the competition with the inhibitor
Vmax stays the same because a high concentration of substrate can overcome inhibition
What is uncompetitive inhibition? How does it affect Km and Vmax?
uncompetitive inhibition is when the binding of the substrate to the active site of an enzyme changes the enzyme’s confirmation to open up a new allosteric site for the uncompetitive inhibitor to bind. Inhibitor ONLY binds to enzyme-substrate complex
Km is decreased since the substrate gets “locked in” the enzyme and the enzyme has “increased affinity” with substrate
Vmax is decreased since this form of inhibition cannot be overcome by increasing substrate concentration
What is mixed inhibition? How does it affect Km and Vmax?
Mixed inhibition is very similar to noncompetitive inhibition. Inhibitor can bind either to the allosteric site of the enzyme or enzyme-sub complex but now has a different affinity of each of these states
Km is higher if the mixed inhibitor binds more readily to the enzyme
Km is lower if the mixed inhibitor binds more readily to the enzyme-substrate complex (“locked-in”)
Vmax decreases because increasing substrate concentration wouldn’t lead to more enzymes being available
