Brainscape's Knowledge GenomeTM

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


See full index

FOM > Week 2-Cell structure > Flashcards

Week 2-Cell structure Flashcards

1
Q

What is the most charged membrane phospholipid?

A

phosphatidyl serine

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

What are the 4 major membrane phospholipids?

A

phosphatidyl-ethanolamine, phophatidyl-serine (both amino phospholipids)
phosphatidyl-choline, sphingomyelin (both choline phospholipids)
first 3 are all phosphoglycerides

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

Functions of cholesterol

A

stiffens membrane, reduces permeability, inhibits phase changes; head is hydrophilic and points outward

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

Where are glycolipids present on cell membranes?

A

non-cytosolic side

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

What is the main function of phosphatidylinositol phospholipids?

A

6 carbon ring can be phosphorylated/dephosphorylated differently to bind different proteins that take part in various intercellular functions

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

Where are phosphoglycerides made?

A

ER, but sphingosine synthesized in Golgi for sphingomyelin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What occurs during plasma membrane translocation to phospholipid distribution?

A

initially evenly distributed, choline-containing phospholipids are flipped to non-cytosolic leaflet, amino phospholipids shifted to cytosolic leaflet

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

What are the components of lipid rafts?

A

sphingolipids, cholesterol, proteins

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

What exactly comprises a glycocalyx? and what is its function?

A

It is made of membrane proteins that have sugars covalently attached; function in protection, identification, and adhesion

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

What are the four mechanisms to organize integral membrane proteins?

A

1- self-assembly into aggregates
2- tethered to extracellular molecules
3- tethered to intracellular molecules
4- bind to proteins on adjacent cells

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

What is the function of the rough ER?

A

protein synthesis of membrane bound proteins (not cytosolic proteins)

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

What are the functions of the smooth ER?

A

lipid synthesis, Ca++ regulation, detoxification

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

Give an example of a cell that would have a lot of rough ER and a cell that would have a lot of smooth ER

A 
RER = B cells because they produce a lot of Abs
SER = liver cells, detoxifying
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What determines if a polyribosome is attached to an ER membrane?

A

polypeptide chain will possess an ER signal sequence, signaling polysome to remain attached

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

What determines if a polypeptide is released into the ER lumen or made into a single/multipass membrane protein?

A

determined by number and orientation of start/stop sequences in polypeptide chain; also determines which end is orientated toward which side

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

What is the directionality of vesicular transport through golgi?

A

products fuse with cis face, packaged and released through trans face

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

What are the three pathways for materials to enter the golgi?

A

endocytosis, phagocytosis, autophagy

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

How to endosomes mature before fusion with Golgi vesicles?

A

pump protons into lumen –> decrease pH –> activates hydrolyses –> condense and are now lysosomes

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

What is the signal to identify lysosomal enzymes?

A

phosphorylated mannose residues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the constitutive secretory pathway?

A

way for vesicles to leave golgi through direct exocytosis – lack of signal leads to this

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where does N-linked glycosylation of proteins occur and where is the sugar linked?

A

linked to asparagine, occurs in lumen of ER, modified in golgi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where does O-linked glycosylation occur and where is the sugar linked?

A

linked to serine or threonine, occurs in golgi or outside of cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the class of heavily O-linked glycosylated proteins and what are their sugar chains?

A

proteoglycans, made of glycosaminoglycan (GAG)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What gives the extracellular matrix its properties?

A

sugars on proteoglycans are sulfated, negative charge – attracts water to form hydragels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Where are misfolded proteins degraded?

A

misfolded proteins are ubiquinated and destroyed by proteosomes in the cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What disease is associated with lysosomal dysfunction?

A

Tay-sachs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the three pathways out of the Golgi?

A

two secretory (constitutive and regulated) and one lysosomal pathway

28
Q

What are caveolae and what is their purpose?

A

invaginations that can lead to uncoated vesicles –> vesicles can transport cargo from one side of cell to the other through transcytosis

29
Q

What is characteristic of clathrin coated vesicles?

A

honeycomb look due to polymerization of clathrin proteins which are shapped like triskelions

30
Q

What are coatamer (COP) 1 and 2 associated with?

A

transport back and forth between Golgi and ER

31
Q

What is the main purpose of clathrin coated vesicles?

A

receptor mediated endocytosis; transport from Golgi to endosome/lysosome and from plasma membrane to endosome/lysosome

32
Q

What removes the clathrin coat from vesicles?

A

ATPases (members of heat shock protein family)

33
Q

What proteins functions as molecular switches and take part in COP1 and COP2 vesicle coating?

A

G proteins; become active and unactive through GTPases (active=GTP, inactive=GDP)

34
Q

What is KEDL?

A

an amino acid sequence on ER proteins that allows them to be returned to ER if they end up in the Golgi

35
Q

What proteins play an important role in delivery and fusion of vesicles?

A

Rabs, Rab effectors, SNAREs

36
Q

What is the system by which SNAREs work?

A

the vesicle has a v-SNARE protein and the target has a corresponding t-SNARE; must recognize each other

37
Q

How do Rab proteins know which membranes to bind to?

A

inositol phospholipids – specificity in their phosphorylation leads to recognition of membrane for Rab binding

38
Q

Where do mitochondria tend to localize?

A

near site of high ATP utilization and along microtubules; often close connection to ER

39
Q

How are proteins brought into mitochondria from cytoplasm?

A

through translocator complexes that recognize alpha-helical protein structure with hydrophobic residues along one side (for TOMS and TIMS)

40
Q

What are TOMS and TIMS?

A

transporters of outer mitochondrial membrane or inner, respectively

41
Q

What is OXA?

A

transports protein from matrix OUT of mitochondria

42
Q

What inserts lipids into the mitochondrial membrane?

A

exchange proteins remove lipids from ER to insert into mitochondrial membranes

43
Q

What are the functions of peroxisomes?

A

detox, beta-oxidation of some fatty acids, formation of myelin phospholipids

44
Q

What is the outer edge of the nuclear matrix lined with?

A

lamins make up the scaffolding of the nuclear matrix; they are part of the intermediate filament family

45
Q

What exactly is the nucleolus?

A

ribosome producing factory; contains the chromosomes that have the duplicated genes of rRNA –tons of transcription and production of rRNA

46
Q

What size proteins can diffuse through nuclear pores?

A

5000 daltons - 60K daltons

47
Q

What type of protein will most quickly be transported to the nucleus?

A

any protein with a nuclear localization signal (NLS)

48
Q

How do proteins larger than 60kDaltons get into the nucleus?

A

through active transport that uses energy and receptor proteins

49
Q

What are the characteristics of imported proteins (to nucleus)?

A

Bind import receptors in the presence of GDP, and dissociate in the presence of GTP

50
Q

What are the characteristics of exported proteins (to nucleus)?

A

Bind export receptors in the presence of GTP, and dissociate in the presence of GDP

51
Q

What controls the directionality of transport of proteins to and from the nucleus?

A

small G-protein called Ran

52
Q

Where are Ran-GEF and Ran-GAP found?

A

Ran-GEF (exchange factor) - nucleus

Ran-GAP (activating protein) - cytoplasm

53
Q

What is the protein microfilament and what are its functions?

A

actin; cell shape, division and motility, also support/organize plasma membrane

54
Q

What is the microtubule protein and what are its functions?

A

tubulin; organize cytoplasm, intracellular transport (railroad), cell division, cilia/flagellae motility

55
Q

What are the functions of intermediate filaments?

A

strengthen cytoplasm/tissues, support nucleus, epidermal appendages

56
Q

Where are microtubules localized?

A

near nucleus by spanning out from their centrosome

57
Q

How are actin filaments constructed/deconstructed?

A

remove monomers from - end and add to the + end

58
Q

How are tubulin filaments constructed/deconstructed?

A

ossicilations of slow growth and rapid breakdown (called dynamic instability) – determined by whether the end units have hydrolyzed their GTP; occurs on + end

59
Q

What regulates polymerization of intermediate filament proteins?

A

polymerize when unphosphorylated, depolymerize when phosphorylated; do NOT have an inherent polarity

60
Q

What is the arrangement of tubulin filaments?

A

alpha-beta dimers form protofilaments, 13 protofilaments form hollow cylinder

61
Q

What is the arrangement of intermediate filament proteins?

A

two alpha helices wrap together to form coil-coil –> two dimers form tetramer (doesn’t have an inherent polarity to it due to opposite association of dimers)

62
Q

How do actin filaments move forward?

A

polymerization causes the head to move forward ; associated with myosin for muscle contraction

63
Q

What does the Rho family of proteins do?

A

activate various actin-binding proteins for microfilament organizaton; includes Rho, Rac, and Cdc42

64
Q

What microtubule-associated (tubulin) proteins are motor proteins?

A

dynein, kinesin

65
Q

What family of cytoskeleton proteins connect epithelial cells at cell-cell junctions?

A

intermediate filaments; also found in nucleus to support nuclear envelope

FOM (11 decks)

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