NS6: BBCF Flashcards
pH and pI relationship
ignore R for a second
pH < pI means both end are protonated
pH = pI means that only the amide is protonated
pH > pI means that both are deprotonated
same rules hold for pKa
thus, at a pH below its pI, the protein will move toward the right, toward the cathode. Since the cathode is negative, this means that the protein must be positive.
glucagon pI
Glucagon has 3 acidic and 4 basic side groups. This tells us that we would expect the pI to be near neutral or slightly basic
note: basic AA’s have a pI greater than 7 while acidic AA’s have a pI less than 7 (just like pH)
alanine pI
While alanine has no acidic or basic side groups, it still does have an amino terminus and a carboxy terminus that contribute to the pI calculation. A basic understanding of pI leads us to the recognition that in an amino acid like alanine, we can simply take the average of the pKas of the amine and carboxy termini. This gives us (2 + 9) / 2 = 5.5.
Which of the following sequences identifies the cellular locations of a secreted protein product after its release from the ribosome?
Release from RER Ribosome → Rough endoplasmic reticulum → Golgi apparatus → plasma membrane → extracellular space
What’s in the cytoplasm of a eukaryotic cell, incl organelles?
- n3
NUCLEUS
Nuclear envelop: membrane enclosing the nucleus; protein lined pores allow material to move in and out
Chromatin: DNA plus associated proteins (histones) that allow for condensing or loosening during DNA transcription
Nucleolus: condensed region where ribosomes are formed
What’s in the cytoplasm of a eukaryotic cell, incl organelles?
- c4
CYTOSKELETON
Microtubules: form the mitotic spindle and maintain cell shape; involved in pulling chromosomes or chromatids apart during anaphase
Centrosome: microtubule organizing center
Intermediate filaments: fibrous proteins that hold organelles in place
Microfilaments: fibrous proteins from the cellular cortex
What’s in the cytoplasm of a eukaryotic cell, incl organelles?
- er2
- everything else (6)
Endoplasmic reticulum:
- Rough: studded w ribosomes that make secreted or membrane bound proteins
- Smooth: make lipids
Lysosome: digests food and waste materials
Peroxisome: metabolizes waste using hydrogen peroxide
Golgi apparatus: modifies and packages secreted / membrane bound proteins
Mitochondria: produce energy via aerobic respiration processes
Plasma membrane
Vacuole
In what way does the synthesis of phage proteins in the infected cell differ from protein synthesis in a eukaryotic cell?
Eukaryotic protein synthesis occurs on 80S ribosomes.
These are distinct in their subunit composition from 70S ribosomes, which are found exclusively in prokaryotes.
Recall that “Phage” is short for “bacteriophage,” meaning a virus that reproduces using the host prokaryotic machinery.
what makes up PCR?
PCR uses DNA primers, thus do not use uracil.
Additionally, primers will look exactly like the gene that is intended to be transcribed – why?
- Primer is initially DNA, but will transcribe a mRNA complement.
- This mRNA complement is then reverse-transcribed … thus yielding the original primer strand (which matches the target gene strand!)
what direction does DNA poly read?
Eukaryotic DNA polymerases ε and δ are principally responsible for the elongation of the leading and lagging strands, respectively, during DNA replication.
Both polymerases read the parental nucleotide template in the 3’ → 5’ direction, adding nucleotides to the growing strand in the 5’→ 3’ (antiparallel) direction.
Which of the following correctly identifies the order of development from fertilization to differentiation of the GI system?
Zygote → morula → blastula → endodermal cells → lining of archenteron → GI system
how are lipid peroxides formed?
by free-radical attack on a lipid
Thus, we expect the location with the most lipid peroxidation to be someplace where oxygen is participating in a redox reaction.
- As it so happens, the electron transport chain, which is located on the inner mitochondrial membrane, has oxygen as its terminal electron acceptor.
- The electron transport chain can “leak,” producing free radicals such as superoxide that react with nearby lipids to make lipid peroxides.
electron carriers in ETC (5)
NADH-Q reductase, ubiquinone, cytochrome reductase, cytochrome c, and cytochrome oxidase
Each carrier in the electron transport chain is only capable of carrying one or two electrons at a time.
lymphatic system
part of both the circulatory and immune systems; acts as a parallel circulatory system that drains interstitial fluid from the space surrounding the cells of the tissue
Collects lymph from the capillaries and returns them to the circulatory system at the intersection of the internal jugular veins and subclavian veins
Also connected to the digestive system bc used to transport lipids, in the form of chylomicrons, to the circulatory system
lymph nodes
filtration points for the lymphatic fluid where reservoirs of B and T cells are stored
Located at the head, neck, chest, underarms, abdomen, and groin
swollen lymph nodes (felt upon palpation) may be a sign of conditions such as systemic infections or cancers
