Molecular Biology I

Question 0

What is the extra- and intra-cellular concentrations (mM) of K+?

Answer 0

Extra: 3.5-5

Intra: ~150

Question 1

What is the extra- and intra-cellular concentrations (mM) of Na+?

Answer 1

Extra: 135-150

Intra: ~15

Question 2

What is the extra- and intra-cellular concentrations (mM) of Ca2+?

Answer 2

Extra: ~1.3

Intra: ~0.1 (or ~100microMolar)

Question 3

What is the extra- and intra-cellular concentrations (mM) of Mg2+?

Answer 3

Extra: ~0.6

Intra: ~0.8

Question 4

What is the extra- and intra-cellular concentrations (mM) of H+?

Answer 4

Extra: 35-45nM (pH = 7.35-7.45)

Intra: ~100nM (ph ~ 7)

Question 5

What is the extra- and intra-cellular concentrations (mM) of Cl-?

Answer 5

Extra: 100-120

Intra: ~5 - ~80

Question 6

What is the extra- and intra-cellular concentrations (mM) of HCO3-?

Answer 6

Extra: 22-27
Intra: ~10

Question 7

What are the two major types of epithelial cells?

Answer 7

Stratified: mechanical protection (skin)
Simple: secretion and absorption (lungs)

Question 8

Where is the epithelia specialized for exchange?

Answer 8

The lungs. 02 and CO2

Question 9

Where is epithelia specialized for absorption?

Answer 9

The gut and kidneys.

Question 10

How many cells are in our body?

Answer 10

37 trillion

Question 11

What are two proteins used in proof reading?

Answer 11

EF-Tu and EF-G

Question 12

When are the proofreading proteins used?

Answer 12

1. EF-Tu comes in with the new tRNA and AA and make sure it fits into the A site of the ribosome.
2. 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.

Question 13

What are the three sites in the ribosome? Function?

Answer 13

1. A: where new tRNA comes in with new AA (when this happens, rRNA in E site gets kicked out.)
2. P: where chain is actually elongated.
3. E: exit chamber for no longer needed tRNA.

Question 14

Does proofreading require energy?

Answer 14

Yes. GTP to GDP for use of both EF-Tu and EF-G.

Question 15

What percent of the cell’s membrane is the plasma membrane?

Answer 15

About 5%.

Question 16

How does transportation to the cell membrane change a protein?

Answer 16

• often makes them active
• lots of conformational changes as they enter the membrane.
• bind with other proteins.

Question 17

What is the life cycle of a protein? (what can go wrong?)

Answer 17

i) Conception: Replication and Transcription (mutations)
ii) Birth: Translation (misincorporation, premature termination)
iii) Maturation: Folding (misfolding)
iv) Death: Degradation (accumulation)

Question 18

What determines a proteins 3D structure?

Answer 18

The 1D AA sequence. (however, sometimes the environment can influence it.)

Question 19

How is protein folding determined?

Answer 19

The protein moves towards a lower free energy, and that determines structure.

Question 20

Describe the analogy of a protein’s intermediate state.

Answer 20

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.

Question 21

Do most proteins have an intermediate state?

Answer 21

yes.

Question 22

Who does the ribosome give a new protein to?

Answer 22

Chaperone Proteins.

Question 23

What is the role of chaperones?

Answer 23

They facilitate the folding of proteins.

Question 24

When are proteins unfolded?

Answer 24

1. translocation 2. degradation 3. post translation modification 4. stress can unfold proteins.

Question 25

What are heat shock proteins?

Answer 25

Chaperone proteins.

Question 26

What are the 5 families of HSPs?

Answer 26

1. sHSPs (small) 2. HSP60 3. HSP70 4. HSP90 5. HSP100

Question 27

What do sHSPs do?

Answer 27

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.

Question 28

What do HSP90s do?

Answer 28

fold steroid hormone receptors and oncogenic kinases.

Question 29

What does HSP100 do?

Answer 29

Disaggregate large aggregates.

Question 30

What does HSP70 do?

Answer 30

It works with HSP90 and HSP100. Binds to new proteins very early on as it leaves the ribosome.

Question 31

What do HSP60 do?

Answer 31

?

Question 32

What are the two major degradation pathways?

Answer 32

1. Proteasomes | 2. Autophagosomes

Question 33

What causes Cystic Fibrosis?

Answer 33

the CFTR protein does not fold properly, so it is degraded.

Question 34

What is a prion?

Answer 34

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.

Question 35

What are epithelium?

Answer 35

- 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

Question 36

What are two classifications of epithelia?

Answer 36

1. Layers: simple, stratified, pseudo-stratified | 2. Shape: squamous, cuboidal, columnar

Question 37

What are 2 types of epithelia?

Answer 37

1. Endothelium: lines lumen of blood vessels | 2. Mesothelium: lines all cavities of the body and surfaces of abdominal organs.

Question 38

Flux is proportional to?

Answer 38

R squared

Question 39

Concentration is proportional to?

Answer 39

1/r