What Does DNP Actually Do? - ✔✔ DNP is a weak acid due to its -OH group, •This means that some of the time it can shed its proton, becoming -O-+
... [Show More] H+. This is unlike HCl, which is a strong acid, and thus completely dissociates in water.
You have created some artificial membrane vesicles that have a higher pH inside than the aqueous solution outside. To sample 1 of these vesicles you add a little HCl, and to the other (sample 2) you add some DNP and then measure the internal pH of the vesicles. What do you predict would happen? - ✔✔ remain unchanged in 1 but decrease in 2.
When protonated (carrying its H+proton) as you saw in the figure, DNP will be uncharged and very hydrophobic. It is hence readily soluble in lipid bilayers such as those enclosing these vesicles (and those of the mitochondrial inner membrane).Thus DNP can readily carry protons across the membrane from a higher concentration (lower pH) outside, and release them to the lower concentration (higher pH) inside. This equilibrates the pH inside and outside. HCl cannot do this, because it is not hydrophobic, and its charged ion species (H+and Cl-) cannot cross lipid bilayer structures.
You incubate isolated intact mitochondria in a buffered solution with succinate, and ADP plus Pi. You add oligomycin(the ATP synthase inhibitor), then the compound DNP (2,4-dinitrophenol), and examine the effect on oxygen consumption and the production of ATP. What do you predict? Hint: On taking DNP as a weight-loss drug, people experienced weakness, sweating, and hyperventilation - ✔✔ Oxygen will be consumed but no ATP will be produced. DNP acts as an uncoupler!
And working like crazy' needs a lot of________, and generates a lot of___________ (fill in the blanks) - ✔✔ Increased Oxygen consumption -to pump all those protons back out, oxygen has to be there to accept the electrons passing through the ETC.•Heat generation -Energy converted from one form to another (second law of thermodynamics) •
Does this fit with the effects you know that DNP has on people? Yes! rapid breathing because they need oxygen, sweating from the increase in body temperature due to the heat generated, and fatigue because ATP stops being made, even though lots of calories are being burned.
DNA polymerase - ✔✔ is an enzyme that catalyzes DNA synthesis
DNA Polymerase II - ✔✔ extends the leading strand
DNA Polymerase III - ✔✔ extends Okazaki fragments
DNA Polymerase I - ✔✔ Removes primer and replaces it with DNA
primase - ✔✔ catalyzes the synthesis of the RNA primer
primer - ✔✔ Is a short strand of RNA or DNA (generally about 18-22 bases) that serves as a starting point for DNA synthesis. It is required for DNA replication because the enzymes that catalyze this process, DNA polymerases, can only add new nucleotides to an existing strand of DNA.
helicase - ✔✔ catalyzes the breaking of hydrogen bonds between base pairs to open the double helix
single-strand DNA binding proteins - ✔✔ stabilizes single strand DNA
sliding clamp - ✔✔ holds DNA polymerase in place during strand extension
topoisomerase - ✔✔ breaks and rejoins the DNA duble helix to relieve twisting forces caused by the opening of the helix.
Makes sure DNA doesn't overwind or underwind
How Does Replication Start? - ✔✔ A replication bubble forms in a chromosome that -Is actively being replicated -Grows as DNA replication proceeds because synthesis is bidirectional•In bacterial chromosomes, the replication process -Begins at a single location (origin of replication)•Eukaryotes also have bidirectional replication-But they have multiple origins of replication -And they have multiple replication bubbles•A replication fork is the Y-shaped region where the DNA is split into two separate strands for copying
How Is the Leading Strand Replicated? - ✔✔ DNA polymerase requires a primer-A few nucleotides are bonded to the template strand-This provides a free 3' hydroxyl (OH) group that can combine with an incoming dNTPto form a phosphodiesterbond
Primase-A type of RNA polymerase-Synthesizes a short RNA segment that serves as a primer -DNA polymerase III then adds bases to the 3' end of the primer•One product is called the leading strand, or continuous strand-It leads into the replication fork -It is synthesized continuously in the 5ʹ--3ʹ direction
What about the Lagging Strand? - ✔✔ The other DNA strand is called the lagging strand-It is synthesized discontinuously-In the direction away from the replication fork-It occurs because DNA synthesis must proceed in the 5' ---3' direction
How Is the Lagging Strand Replicated? - ✔✔ Is synthesized as short discontinuous fragments called Okazaki fragments•Synthesis starts when primasesynthesizes a short stretch of RNA that acts as a primer•DNA polymerase III then adds bases to the 3' end of the primer•DNA polymerase moves away from the replication fork -Helicase continues to open the replication fork -And expose single-stranded DNA on the lagging strand•DNA polymerase I removes the RNA primer at the beginning of each Okazaki fragment and fills in the gap •The enzyme DNA ligase joins the Okazaki fragments to form a continuous DNA strand
Side effect - ✔✔ nearly unavoidable secondary drug effect produced at therapeutic doses
Toxicity - ✔✔ degree of detrimental physiologic effects caused by excessive drug dosing
Adverse effects - ✔✔ any noxious, unintended, and undesired effect that occurs at normal drug doses
Schedule I drug - ✔✔ have no accepted medical use in the US and are deemed to have a high potential for abuse
Schedules II through V drugs - ✔✔ have accepted medical applications but also have a high potential for abuse
How do drugs cross cell membranes? - ✔✔ 1. pass through channels or pores (least common)
2. pass with aid of transport system
3. direct penetration of membrane (most common)
What has the ability to pass through channels or pores? - ✔✔ potassium and sodium
What are membranes primarily composed of? - ✔✔ lipids
To directly penetrate a membrane, a drug must be? - ✔✔ lipid soluble (lipophilic)
What group cannot penetrate membranes? - ✔✔ polar molecules and ions
Example of a polar drug? - ✔✔ gentamicin
Factors that affect drugs absorption - ✔✔ 1. rate of dissolution
2. surface area
3. blood flow
4. lipid solubility
5. pH partitioning
Factors that affect drug distribution - ✔✔ 1. blood flow to tissues
2. ability of drug to exit vascular system
3. ability of drug to enter cell [Show Less]