Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FBS1 > Cell Biology & Signalling > Flashcards

Cell Biology & Signalling Flashcards

1
Q

What is tyrosine the precursor of?

A

Epinephrine, dopamine and melanin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is tryptophan the precursor of?

A

Serotonin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the essential amino acids?

A 
Phenylalanine, F
Valine, V
Tryptophan, W
Threonine, T
Isoleucine, I
(Methionine, M)
Histidine, H
(Arginine, R)
Leucine, L
Lysine, K
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Anchored membrane proteins examples

A 
Alkaline phosphatase (glycolipid anchored)
RAS (fatty acyl anchored)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Peripheral proteins example

A

Spectrin (interacts with ankyrin)

Phospholipase A2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the different phospholipases?

A 
PLA1,2= FA from phospholipid
PLC= phosphate group from glycerol
PLD= phosphate group from polar head group
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the effect of pH on the affinity of Hb for oxygen?

A

Increase in pH —> increase in affinity

Decrease in pH —> decrease in affinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the effect of BPG on Hb affinity to O2?

A

Increased BPG —> decreased affinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where on hemoglobin does heme bind?

A

Histidine residues from helixes E7 (distal) and F8 (proximal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What mutation causes sickle cell anemia?

A

Glu6 (acidic) to Val (nonpolar) in beta-chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are porphyria and thalassemia?

A

Porphyria: inherited defect in synthesis of heme group
Thalassemia: reduced synthesis of alpha or beta chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does protein targeting to the ER happen?

A

signal sequence at N-terminus, recognised by signal recognition particle (SRP), SRP receptor in ER membrane, translocation channel, signal peptidase cleaves signal sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the tag for proteins that form lysosomes?

A

mannose-6-phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does protein targeting to mitochondria happen?

A

translated but unfolded protein, chaperones take it to the mitochondria, signal sequence recognised by receptor –> translocation across outer and inner m, cleavage of signal sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does protein targeting to the nucleus happen?

A

Translation and folding in cytoplasm, nuclear localisation signal (NLS; basic) binds to importin and transported through the nuclear pore, requires G-protein Ran and GTP,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are glycosyltransferases?

A

Golgi enzymes that add sugars to proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How many actin monomers are needed for a full turn and what is the diameter of the filament?

A

13; 7 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the major functions of actin?

A

Mechanical support, cell shape changes and maintenance, cell motility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the diameter of intermediate filaments and what are some examples?

A

10 nm; keratin, vimentin, glial fibrillary acidic protein, neurofilamin

20
Q

What is plectin?

A

protein links IFs to actin and microtubules

21
Q

How many columns of tubulin polymer are arranged to form the microtubule and what is its diameter?

A

15; 25 nm

22
Q

What is required for the assembly of actin filaments and microtubules?

A

Actin filaments: ATP

Microtubules: GTP

23
Q

What is responsible for shape of microvilli and stereocilia?

A

Actin filaments

24
Q

What is responsible for the organisation the ER of a cell, nucleus support and synaptic vesicle positioning?

A

ER: microtubules
Nucleus: intermediate filaments
Synaptic vesicles: actin filaments

25
Q

What molecules are responsible for focal adhesion?

A

Integrins

26
Q

What are examples of microtubule based movements?

A

Cilia and flagellae

9+2 structure + dynein

27
Q

What motor protein is responsible for movement of lamellipodia?

A

Myosin II (requires ATP, not processive)

28
Q

Which motor proteins are responsible for movement of organelles and intracellular contents?

A

Kinesin (processive motor protein, requires ATP) and dynein (both have heavy and light chain) on microtubules

29
Q

What are colchicine, vinblastine and taxol?

A

Anti-cancer therapeutics;
Colchicine and vinblastine: destabilise microtubules
Taxol: stabilises microtubules

30
Q

What is Tau and what happens to it in Alzheimer’s disease?

A

Microtubule associated protein

In AD it is hyperphosphorylated and thus cannot bind to MTs

31
Q

How does the Listeria bacteria interfere with the cytoskeleton of the cell?

A

F-actin is polymerised at the back of the bacterium providing mobility

32
Q

What is sphingomyelin composed of?

A

Ceramide (sphingosine + fatty acyl chain) + phosphate group + choline

33
Q

What is the partition coefficient?

A

Equilibrium constant for the partitioning of a molecule between oil and water (the higher the more lipid soluble)

34
Q

What are the characteristics of GLUT1, 2, 3, 4, 5?

A

GLUT1: low Km, many tissues, highly expressed in erythrocytes and blood-brain barrier
GLUT2: high Km and large Jmax (high capacity), hepatocytes and pancreatic beta cells.
GLUT3: low Km, high expression in neurons
GLUT4: muscles and adipocytes, regulated by insulin.
GLUT5: fructose transporter

35
Q

How does ouabain work?

A

blocks Na+/K+ ATPase –> increase in intracellular sodium –> Na+/Ca2+ antiporter is inhibited –> increase in intracellular Ca2+ –> cardiac muscle contraction

36
Q

What is SGLUT1 and where is it located?

A

Na+/glucose transporter; intestinal epithelial cells and proximal tubules of the kidney for reabsorption of glucose

37
Q

What is the method of action of cholera?

A

Overacting Gsalpha –> increased cAMP levels –> increased transport of Cl- out of the cell through CFTR –> diffusion of Na+ and water out of the cell –> glucose replacement therapy drives Na+ back through SGLUT1

38
Q

What type of receptor is the beta adrenergic receptor?

A

G-protein coupled receptor

39
Q

How are G-proteins activated?

A

GTP binds to alpha subunit –> dissociates from beta and gamma subunits

40
Q

How is PKA activated?

A

cAMP binds to regulatory subunits (2) –> tetramer dissociates and catalytic monomers are now active

41
Q

How is glycogen breakdown activated?

A

Glucagon activates GPCR –> cAMP –> PKA
PKA: phosphorylates and thus activates phosphorylase kinase
Phosphorylase kinase: phosphorylates and thus activates glycogen phosphorylase
Glycogen phosphorylase: phosphorylates glycogen and thus produces glucose-1-phosphate

42
Q

How is gene transcription activated through GPCR?

A

PKA phosphorylates CREB –> binds to specific target sequences in target genes and stimulates transcription

43
Q

How is PLC activated and what does it do?

A

PLC is activated by GPCRs with Gq subunits (alpha1 adrenergic receptors)
PLC cleaves inositol phospholipids into IP3 and DAG
IP3: activates Ca2+ channels in ER
DAG: together with Ca2+ activates PKC

44
Q

What receptor does EGF bind to and what cascade does it initiate?

A

Receptor tyrosine kinase (RTK);
Binding leads to autophosphorylation of tyrosine residues
Adaptor proteins contain phosphotyrosine binding domains: SH2 and PTB
Binding of adaptor proteins (Grb2, Sos) –> activation of Ras through GDP to GTP exchange

45
Q

What is Ras?

A

Monomeric G-protein
GTP-Ras triggers kinase cascade:
MAPKKK –> MAPKK –> MAPK –> transcription factor

FBS1 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions