Molecular Biology I Flashcards
What is the extra- and intra-cellular concentrations (mM) of K+?
Extra: 3.5-5
Intra: ~150
What is the extra- and intra-cellular concentrations (mM) of Na+?
Extra: 135-150
Intra: ~15
What is the extra- and intra-cellular concentrations (mM) of Ca2+?
Extra: ~1.3
Intra: ~0.1 (or ~100microMolar)
What is the extra- and intra-cellular concentrations (mM) of Mg2+?
Extra: ~0.6
Intra: ~0.8
What is the extra- and intra-cellular concentrations (mM) of H+?
Extra: 35-45nM (pH = 7.35-7.45)
Intra: ~100nM (ph ~ 7)
What is the extra- and intra-cellular concentrations (mM) of Cl-?
Extra: 100-120
Intra: ~5 - ~80
What is the extra- and intra-cellular concentrations (mM) of HCO3-?
Extra: 22-27
Intra: ~10
What are the two major types of epithelial cells?
Stratified: mechanical protection (skin)
Simple: secretion and absorption (lungs)
Where is the epithelia specialized for exchange?
The lungs. 02 and CO2
Where is epithelia specialized for absorption?
The gut and kidneys.
How many cells are in our body?
37 trillion
What are two proteins used in proof reading?
EF-Tu and EF-G
When are the proofreading proteins used?
- EF-Tu comes in with the new tRNA and AA and make sure it fits into the A site of the ribosome.
- After chain has been elongated, EF-G comes in to make sure it’s all good. When A site is restored, EF-G gets kicked off.
What are the three sites in the ribosome? Function?
- A: where new tRNA comes in with new AA (when this happens, rRNA in E site gets kicked out.)
- P: where chain is actually elongated.
- E: exit chamber for no longer needed tRNA.
Does proofreading require energy?
Yes. GTP to GDP for use of both EF-Tu and EF-G.
What percent of the cell’s membrane is the plasma membrane?
About 5%.
How does transportation to the cell membrane change a protein?
- often makes them active
- lots of conformational changes as they enter the membrane.
- bind with other proteins.
What is the life cycle of a protein? (what can go wrong?)
i) Conception: Replication and Transcription (mutations)
ii) Birth: Translation (misincorporation, premature termination)
iii) Maturation: Folding (misfolding)
iv) Death: Degradation (accumulation)
What determines a proteins 3D structure?
The 1D AA sequence. (however, sometimes the environment can influence it.)
How is protein folding determined?
The protein moves towards a lower free energy, and that determines structure.
Describe the analogy of a protein’s intermediate state.
UF protein is like an atom in gaseous state.
Intermediate protein is like an atom as a liquid, more structure but very mobile.
Folded proteins are like a crystal.
Do most proteins have an intermediate state?
yes.
Who does the ribosome give a new protein to?
Chaperone Proteins.
What is the role of chaperones?
They facilitate the folding of proteins.
When are proteins unfolded?
- translocation
- degradation
- post translation modification
- stress can unfold proteins.
What are heat shock proteins?
Chaperone proteins.
What are the 5 families of HSPs?
- sHSPs (small)
- HSP60
- HSP70
- HSP90
- HSP100
What do sHSPs do?
Provide an alternate surface for mis/unfolded proteins to bind to so that the cell can deal with them more easily. Help refold misfolded proteins.
What do HSP90s do?
fold steroid hormone receptors and oncogenic kinases.
What does HSP100 do?
Disaggregate large aggregates.
What does HSP70 do?
It works with HSP90 and HSP100. Binds to new proteins very early on as it leaves the ribosome.
What do HSP60 do?
?
What are the two major degradation pathways?
- Proteasomes
2. Autophagosomes
What causes Cystic Fibrosis?
the CFTR protein does not fold properly, so it is degraded.
What is a prion?
A misfolded protein that can cause other of the same type of proteins to also become misfolded. It is infectious and the cause of Mad Cow’s Disease.
What are epithelium?
- avascular tissue, covers exterior body and closed cavities
- polar: apical, basal and lateral
- cell junctions: adherents, tights junctions, desmosomes
- basal lamina
- microvilli, cilia, other special appendages
What are two classifications of epithelia?
- Layers: simple, stratified, pseudo-stratified
2. Shape: squamous, cuboidal, columnar
What are 2 types of epithelia?
- Endothelium: lines lumen of blood vessels
2. Mesothelium: lines all cavities of the body and surfaces of abdominal organs.
Flux is proportional to?
R squared
Concentration is proportional to?
1/r