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DIT > 1C Foundations 3 - Organelles > Flashcards

1C Foundations 3 - Organelles Flashcards

1
Q

Embryologic origin of the tissue just proximal to the pectinate line?

A

Endoderm

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2
Q

The origin of the tissue just distal to the anal canal?

A

Surface ectoderm

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3
Q

What is the general amino acid sequence of Nuclear Localization Signals?

A

4-8 amino acids

Rich in Lysine, Arginine and Proline

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4
Q

What are Nuclear Localization Signals a part of?

A

Essential component of proteins bound for or residing in the nucleus (e.g. histones)

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5
Q

How are Nuclear Localization Signals transported to the nucleus?

A

Through recognition by nuclear pores and by ATPase

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6
Q

What happens if there is a single amino acid mutation in Nuclear Localization Signals?

A

It may prevent nuclear transport of the protein

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7
Q

What regulates the cell cycle?

A

Tumor suppressor proteins
Cyclins
Cyclin-dependent kinases

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8
Q

Tumor suppressor proteins between G1 and S phase?

A

Rb

p53

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9
Q

Cancers associated with mutations in the Rb gene?

A

Retinoblastoma

Osteosarcoma

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10
Q

Tumor suppressor gene and gene product that regulates G2 to M phase?

A

p53

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11
Q

Cyclin-dependent kinases’ properties?

A

Constitutive (use ATP to phosphorylase things)

Inactive (must be activated)

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12
Q

Cyclins properties?

A

Regulatory proteins that control cell cycle events

They activate CDKs and are phase specific?

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13
Q

Cyclins + cyclin-dependent kinases –>?

A

phosphorylate target proteins to drive the cell cycle

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14
Q

What are cyclins degraded by when their cell-cycle specific job is complete?

A

Ubiquitin protein ligase

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15
Q

What is ubiquitin?

A

A protein that marks other proteins for destruction by ubiquitin protein ligase

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16
Q

Ubiquitin is important because?

A

It degrades cyclins and hence regulate the cell cycle

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17
Q

What does the tumor suppressor p21, p27 and p57 have in common?

A

They bind to and inactivate cyclin-CDK complexes

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18
Q

Who controls the activation of p21?

A

p53

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19
Q

Molecular process in which cell moves from G1 to S phase?

A

Cyclin D binds and activates CDK4. Then CDK4 phosphorylates the Rb protein –> release of Rb protein from transcription factor E2F. With E2F unbound cell is now free to transcribe and synthesize proteins needed for progression through the S phase. Next: Cyclin E binds to CDK2. After this the cell is allowed to move into S phase.

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20
Q

What proteins are needed through S phase?

i.e. they are needed to synthesize DNA

A

DNA polymerase
Thymidine kinase
Dihydrofolate reductase
Cyclin E

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21
Q

What happens when moving from G2–>M

A

Cyclin A - CDK2 complex –> mitotic prophase. Also: Cyclin B - CDK1 complex activated by cdc25 –> breakdown of nuclear envelope (specifically nuclear lamin breakdown) and initiation of mitosis.

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22
Q

What is the nuclear lamin?

A

Like a skeleton framework inside the nucleus.
Type of intermediate filament.
Has to be broken down in order for the nucleus to be able to break down –> division of cell

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23
Q

Rough Endoplasmic Reticulum (RER) is rough because?

A

It has a lot of ribosomes on it.

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24
Q

What is produced in the RER?

A

Secretory (exported) proteins

N-linked oligosaccharide addition to many proteins also happen here

25
Where are cytosolic and organellar proteins synthesized?
Free ribosomes
26
What are Nissl bodies?
RER of neurons
27
What does Nissl bodies produce?
Enzymes (e.g. Choline acetyltransferase (ChAT)) ACh Peptide neurotransmitters
28
Where in the neuron can you find Nissl bodies?
Dendrite. Not axon
29
What does Smooth Endoplasmic Reticulum produce? | It has another function as well?
Synthesizes Steroids and detoxifies drugs and poisons
30
Where do you find a lot of smooth ER?
Liver hepatocytes | Steroid producing cells of the adrenal cortex
31
Where do you find a lot of RER?
Mucus-secreting goblet cells of the small intestine | Antibody-secreting plasma cells
32
Where does post-translational modifications take place?
Golgi apparatus
33
What is the role of Coat protein 2 (COP2) proteins?
Anterograde trafficking. | From ER to cis-Golgi
34
What is the role of Coat protein 1 (COP1) proteins?
Retrograde trafficking. | From Golgi to ER
35
What is the role of Clathrin?
Helps transport hydrolase enzymes from trans-Golgi --> lysosomes. Also: helps in transport from the plasma membrane --> endosomes (in receptor mediated endocytosis)
36
Golgi Apparatus. Function?
Distribution center of protein and lipids from ER to plasma membrane, lysosomes and secretory vesicles Post-translational modification of proteins and proteoglycans
37
What kind of tissue are proteoglycans important in?
Connective tissue
38
Glycosylation process is where and how?
Golgi. | Core proteins + (e.g. chondroiton sulphate, Heparin suplphate)
39
Golgi can modify what on asparagine?
N-oligosaccharides
40
The Golgi apparatus can add what to Serine and Threonine?
O-oligosaccharides
41
Golgi can can add what to sugars, proteoglycans and tyrosine?
Sulfate groups ("sulfation")
42
Golgi can add what to lysosomal enzymes?
mannose-6-phosphate
43
I-cell Disease
Deficiency in mannose phophorylation. No mannose-6-phosphate to target lysosomal proteins --> secretion out of cell instead of into lysosomes -- > High levels of lysosomal enzymes in plasma. Death by age 8- Corneal clouding, coarse facies, Hepatosplenomegaly (HSM), skeletal abnormalities, restricted joint movementm +/- intellectual disability Similar to Mucoplysaccharidosis like (Hurler or Hunter syndromes)
44
Function of Chaperones in the ER and Golgi?
Assist in proper folding and transport of polypeptides
45
Some chaperones are synthesized constantly and are involved in?
Normal intracellular protein trafficking
46
What is the function of heat shock proteins (also a kind of chaperone). Mention two.
"Rescue" shock-stressed proteins from misfolding (They are sent for degradation). hsp70 and hsp90
47
If a protein is unable to be rescued (it's abnormally folded) what happens?
The heat shock proteins will attach ubiquitin (also a heat shock protein) to them --> degradation
48
Mention the different types of proteolysis
1. Lysosomal degredation (Lysosomal enzymes). 2. Proteasomal degradation (Ubiquitin-tagged protein is recognized by ubiquitin-protein-ligase which is a part of the proteosome complex --> destruction of protein). 3. Calcium-dependent enzymes
49
Function of sarcoplasmic reticulum?
Store calcium and help manipulate Ca2+ balance to regulate muscle contraction
50
Where do you find sarcoplasmic reticulum?
Striated muscle and smooth muscle cells
51
What does Ca2? trigger?
Muscle contraction and exocytosis of neurotransmitters and hormones
52
ATP production happens in which organelle?
Mitochondria
53
ATP happens in which processes?
TCA cycle and Electron transport chain
54
Mitochondria self-replicate. Why?
They have their own DNA
55
Mitochondrial DNA comes from mother or father?
Mother
56
How does the mitochondria relate to Ca2+
It can absorb Ca+ if excess exist in the cytoplasm
57
Function of the membrane-enclosed organelle peroxisomes?
Beta-oxidation of very long chain fatty acids and branched fatty acids and amino acids. Synthesis of plasmalogens. Oxidases and catalase for meatabolizing ethanol and other toxic substances.
58
What are plasmalogens?
Important phospholipid found in myelin
59
What is the proteasome?
Barrel-shaped protein complex that degrades damaged and unnecessary proteins tagged for destruction with ubiquitin.

DIT (11 decks)

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