Brainscape's Knowledge GenomeTM

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


See full index

Exam 2 > Cell Structure 2 > Flashcards

Cell Structure 2 Flashcards

1
Q

What is membrane flow? What organelles are responsible for membrane flow?

A

The transfer of lipids and proteins from the ER to Golgi, lysosomes and the plasma membrane

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

What is the main function of ER, Golgi and lysomes?

A

Formation and transport of membrane bound vesicles.

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

How does the plasma membrane bring materials in and out of the cell?

A

Endocytosis and exocytosis

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

What is familial hyercholesterolemia?

A

An example of a dficit in an endocytic pathway

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

How is the golgi apparatus the “post office” of the cell?

A

It directs material to be transporter along 3 primary routes:

Lysosomes
Secretory vesicles
Plasma membrane

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

What is the golgi apparatus?

A

Consists of: Series of flat cisternae with memranes and tubules

  • Entry, cis face, receives product from ER in form of membrane bound vesicles.
  • The material fuses with golgi cisternae and moves through the apparatus, modified along the way
  • Most lipids and proteins are packaged and released from trans face EXIT.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the functions of the Golgi?

A
  • receives lipid and protein products from ER
  • returns escaped proteins that should be resident in ER
  • Modifies glycoproteins (trimming and additoin)
  • Sulfation and other post-translational modifications
  • Glycolipid and shingomyelin production
  • Adds O linked oligosaccharides to proteoglycans
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does transport between ER, Golgi, lysosomes and plsama occur?

A

Vesicular transport: Fusion of lipid bilayers. MAINTAINS TEH TOPOLOGICAL ORIENTATION OF MEMBRANE PROTEINS AND LIPIDS.

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

What are COPI and COPII and what do they do?

A

They are proteins that coat the ER and golgi membranes to help with vesicle formation and transfer between sites.
COPII- ER to GOLGI
COPI- Intra Golgi and golgi to ER transport.

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

Describe the formation of COPI and COPII coated vesicles. What is KDEL?

A
  1. GEF (Guanine nucleotide exchange factor) catalyzes Sarl-GDP to Sarl GTP (turning it ON!). Sarl then extends a hydrophobic tail into the lipid bilayer
  2. Sarl recruits ADAPTOR PROTEINS and CARGO RECEPTOR proteins that concentrate the cargo and begins to curve the membrane
  3. Sec13/31 is recruited and forms a cage like structure helping hte vesicle to form and pinch off
  4. KDEL bind proteins that escape from ER to Golgi and sends them back
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What mechanisms determine where vesicles go and how they fuse with their appropriate targets?

A
  1. Rabs: MARKERS large subfamily small GTP binding proteins (like Sarl and Arf). Rabs bind to membranes and are markers of each protein type
  2. GTP Rab: TRANSPORT and BIND vesicles to correct target site. Some associated with cytoskleton and help transport vesicles through cytoplasm
  3. Rab effector: TETHERS
  4. Snares: SNARE target and brings it in closer to fuse intergral membrane proteins present in both vesicles and the target membranes MORE
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does the lipid content of a membrane serve as a critical identifier for where vesicles form?

A

Helps determine where vesicles form and fuse.

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

What are the options for Golgi proteins and lipids?What are the three routes out of the golgi?

A
  1. Remain in place (golgi resident)
  2. Returned to ER
  3. Take one of the three paths out:
  4. Signal mediated diversion to lysosomes
  5. signal mediated diversion to secretory vesicles (regulated secretion)
  6. Constitutive secretory Pathyway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are lysosomes?

A

Membrane bound compartments filled with hydrolytic enzymes that carry out intracellular digestion. The acid hydrolases that make up the hydrolytic enzymes are maximally active at low pH, which protects the cell if they escape.

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

Why are lysosomal membranes special?

A
  1. Glycosylated (highly!) for protection
  2. H pumps to create acidic lumen
  3. Transporters to shuttle breakdown products to cytoplasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 3 paths to lysosomes?

A

Autophagy
Phagocytosis
Endocytosis

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

What is Phagocytosis?

A

A form of endocytosis.

Engulfs large particles into large specialized endosomes called phagosomes

(macrophages and neutrophils in humans)

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

What is Endocytosis and how does it work?

A

Process by which cells take up extracellular material by surrounding it with plasma membrane and engulfing it.

Two types: Phagocytosis-ingestion of large particles of bacteria
Pincocytosis- internalization of small particles (can be coated (clathrin) or uncoated (caveolae)

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

How is material digested by endosomes/lysosomes brought into the cell?

A
  1. Pinocytosis (cell drinking):

2. Phagocytosis

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

What is pinocytosis? What is receptor mediated endocytosis? What is transytosis?

A

A continuous process in most cells in which small particles/ECF are brought into the cell.
Receptor mediated endocytosis can bring specific molecules into the cell.
Transytosis- molecules are transported across cell.

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

What is phagocytosis?

A

Ingestion of large particles or bacteria

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

What is the difference between coated and uncoated vesicles?

A

Coated endocytotic vesicle have clathrin as a transient peripheral membrane protein. Forms cage like structure to deform membrane and begin process of vesicle formation.
Uncoated vesicles contain caveolin as a permanent integral protein. “Pits” in plasma membrane that invanginate to form endocytotic vessels.

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

How does Clathrin and receptor mediated endocytosis work?

A
  1. Adaptor protein binds to receptor ligan complexes
  2. Clathrin assembles on adaptor proteins, deforms membrane and formes coated pit
  3. Vesicle invaginates and dynamin piches off neck of vesicle
  4. Uncoating ATPase removes clathrin coat which is recycled
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is exocytosis?

A

Delivers material produce by cell to plasma membrane and extracellular environment. Material to be exocytosed is processed by the Golgi body.

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

What is the difference between a regulated pathway and a constitutive pathway?

A
  1. Constitutive: DEFAULT pathway, materials form with no signals are exocytosed
  2. Regulated: The aggregation and concentration of protein in vesicles that is secreted when the cell receives the right stimulus.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a major function of the golg related to sugars?

A

THe oligosaccharide processing of N linked glycoproteins made in the ER to complex oligosaccharides

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

What are the 3 prominent types of coat proteins involved in vesicular trafficking and what do they do?

A
  1. COP1 Golgi to ER
  2. COP II ER to GOLGI
  3. Clathrin: endocytosis, Golgi to endosomes/lysosomes
28
Q

Recognition of the vesicle and target membranes as well as membrane fusion is mediated by what three proteins?

A
  1. Rabs
  2. Rab effectors
  3. Snares
29
Q

What is transcytosis?

A

Moving material from the extracellular compartment of one side of the epithelium to the extracellular compartment on the other side of the epithelium

30
Q

What is the function of the mitochondria?

A

Convert the oxidation of food into ATP

31
Q

Describe mitochondrial morphology.

A

Mitochondria re localized along MICROTUBULES and establish close connections with the ER.

32
Q

Where are mitochondria located?

A

Sites where there is high ATP utilization: contractile myofibers in cardiac muscle, the sperm tail

33
Q

Describe the mitochondrial network.

A

HIghly dynamic, continually changing undergoing fission and fusion

34
Q

Describe the mitochondrial genome.

A
  1. Small and encodes only a small amount of proteins needed. Most are made in nucleus.
  2. Proteins from the nucleus are moved to the membrane and inserted through specific transporters
35
Q

How do the proteins know to go to the mitochondria?

A
  1. Signal sequence identifier on the polypeptide chain

2. Sequence is not specific, but has a alpha helical structure with hydrophobic residues along one side of the helix.

36
Q

What are the three translocator complexes?

A
  1. TOM- Transporter of the outer mitochondrial membrane
  2. TIM- transpoorters of inner mitochondrial membrane
  3. OXA- Transports porteins synthesized IN matrix
37
Q

What do exchange proteins do?

A

Move lipids from ER and insert in mitochondrial membrane. This is easier because the ER and mitochondria are usually CLOSE together.

37
Q

What do exchange proteins do?

A

Move lipids from ER and insert in mitochondrial membrane. This is easier because the ER and mitochondria are usually CLOSE together.

38
Q

What makes the inner membrane of the mitochondrial special?

A

It has a large amount of cardiolipin.

38
Q

What makes the inner membrane of the mitochondrial special?

A

It has a large amount of cardiolipin.

39
Q

What are peroxisomes?

A
  1. Spherical structures bound by a single membrane
  2. Involved in oxidation reactions: production and removal of hydrogen peroxide
  3. Contains high concentrations of enzymes catalase and urate oxidase
39
Q

What are peroxisomes?

A
  1. Spherical structures bound by a single membrane
  2. Involved in oxidation reactions: production and removal of hydrogen peroxide
  3. Contains high concentrations of enzymes catalase and urate oxidase
40
Q

What are the two important functions of peroxisomes?

A
  1. Detoxification rxns (oxidation of ethanol to acetalaldehyde)
  2. Beta oxidation of fatty acids into acetyl CoA
  3. Formation of myelin phospholipids
40
Q

What are the two important functions of peroxisomes?

A
  1. Detoxification rxns (oxidation of ethanol to acetalaldehyde)
  2. Beta oxidation of fatty acids into acetyl CoA
  3. Formation of myelin phospholipids
41
Q

How are peroxisomes made?

A

Hybrid process of budding from the er and import of proteins made in the cytoplasm and fission.

41
Q

How are peroxisomes made?

A

Hybrid process of budding from the er and import of proteins made in the cytoplasm and fission.

42
Q

What is the nucleus?

A
  1. Holds the genetic material of the cell
  2. Site of DNA synthesis and DNA expression
  3. Consists of chromatin, protein and RNA
  4. Protected by a double membrane = NUCLEAR ENVELOPE
  5. Specialized environment separate from cytoplasm
42
Q

What is the nucleus?

A
  1. Holds the genetic material of the cell
  2. Site of DNA synthesis and DNA expression
  3. Consists of chromatin, protein and RNA
  4. Protected by a double membrane = NUCLEAR ENVELOPE
  5. Specialized environment separate from cytoplasm
43
Q

What is the nuclear matrix?

A
  1. Filament scaffolding made up of lamins/proteins/RNA

2. Provides sites of attachment for specific spots along chromosomes, this helps regulate gene expression

43
Q

What is the nuclear matrix?

A
  1. Filament scaffolding made up of lamins/proteins/RNA

2. Provides sites of attachment for specific spots along chromosomes, this helps regulate gene expression

44
Q

What are the specialized region of chromosomes?

A
  1. telomeres
  2. origins of replication
  3. centromere
  4. heterochromatin
  5. euchromatin
  6. nucleolar organizing region–repeat of ribosomal RNA genes
    * *chromosomes occupy discrete territories in the nucleus
44
Q

What are the specialized region of chromosomes?

A
  1. telomeres
  2. origins of replication
  3. centromere
  4. heterochromatin
  5. euchromatin
  6. nucleolar organizing region–repeat of ribosomal RNA genes, cluster out and form nucleolus (where ribosomal rna is made)
    * *chromosomes occupy discrete territories in the nucleus
45
Q

What are MARS and SARS?

A
  1. Areas specialized to bind to the nuclear matrix
  2. Matrix/scaffold Attachment Regions
  3. Mars are “hot spots” for topoisomerase activity and relieve torisional stress
45
Q

What are MARS and SARS?

A
  1. Areas specialized to bind to the nuclear matrix
  2. Matrix/scaffold Attachment Regions
  3. Mars are “hot spots” for topoisomerase activity that relieve torisional stress during replication and transcription
46
Q

What happens when chromosomes attach to the nuclear matrix at MARS?

A
  1. Formation of large looped domains that function as transcriptional units.
46
Q

What happens when chromosomes attach to the nuclear matrix at MARS?

A
  1. Formation of large looped domains that function as transcriptional units.
  2. Fxnal features of MARS (AT rich sequences) allow them to attach to nuclear matrix
47
Q

What happens to active regions of chromosomes during transcription?

A

They move to preferred locations.

48
Q

What is the nucleolus?

A
  1. Ribosome producing factory
  2. Consists of: rRNA genes, precursor rRNAs, mature rRNAs, rRNA processing enzymes, ribosomal proteins, partially assembled ribosomes
49
Q

What are nucleolar organizing regions?

A
  1. Clusters of rRNA genes that have been dublicated

2. This helps to attract related protein and RNA machinery for ribosome production and form the nucleolus

50
Q

What are the components of the nuclear envelope?

A
  1. Inner nuclear membrane
  2. outer nuclear membrane–connected to ER at multiple sites, perinuclear space of outer membrane is continuous with er lumen
  3. nuclear pores
  4. nuclear lamina- proteinaceous mash-work of filaments that underly inner nuclear membrane
51
Q

What are nuclear pore complexes?

A
  1. Assemblies of pore proteins called nucleoporins
  2. Pores can transport in both directions and are semipermeable
  3. Transport across the pore requires specific receptor proteins
  4. Permeable to molecules 5000 daltons or less, impermeable to 60,000 daltons
52
Q

Where are nuclear proteins made? How do they end up in the nucleus?

A
  1. The cytoplasm
  2. Proteins destined for the nucleas have a NLS (nuclear localiation signal) a short region of aa, not specific by have structural motifs (lysine-rich)
53
Q

What are import and export proteins?

A
  1. Recognition of NLS by nuclear import receptors (recognize different cargo), brings proteins in and out of nucleus
  2. Import proteins: bind import receptors in the presence of GDP and dissociate in presence of GTP
  3. Export: Bind export receptors in the presence of GTP and dissociate in the presence of GDP
  4. G proteins are called RAN– outside GDP Ran cytoplasm, inside GTP nucleus
64
Q

Where is ran GEF concentrated? Where is Ran GAP concentrated?

A
  1. Ran GEF- Nucleus, high in ran-GTP low in Ran GDP

2. Ran GAP-cytoplasm, high GDP, low in GTP

65
Q

What is added to proteins destined for lysosomes?

A

MAN6 PHos

Exam 2 (7 decks)

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