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Molecular Cell Biology > Test 3 - Lecture 25 > Flashcards

Test 3 - Lecture 25 Flashcards

(56 cards)

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1
Q

Mitochondria -

Mitochondrial DNA can be _______ by mutations

A

altered

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2
Q

Mitochondria -
Almost all of the mitochondria of fertilized eggs are contributed by the ______, so germ - line mutations are transmitted to the next generation by the ______

A

oocyte

mother

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3
Q

Mitochondria -
True/False
Mutations in mitochondrial genes are associcated with several dieseases

A

True

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4
Q

Mitochondria -
______ hereditary ______ _______, which leads to blindness, is caused by mutations in mitochondrial genes that encode components of the ______ transport chain

A

Leber’s
optic
neuropathy
electron

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5
Q

Mitochondria -
1. Mammalian mitochondria genomes encode only __ proteins but contain about _____ different proteins encoded by the nuclear genome

A

13

1500

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6
Q

Mitochondria -
2. Proteins encoded by nuclear genes include:
Proteins needed for _______ and ________ of mitochondrial DNA
Most Proteins needed for _______ ________
All the ______ involved in _________ metabolism

A 
replication 
expression
oxidative phosphorylation
enzymes 
mitochondrial
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7
Q

Mitochondria -

3. Most of the proteins are synthesized of ____ ribosomes and imported as complete ________

A

free

polypeptides

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8
Q

Mitochondria -

1. Because of the _____ - ______ structure of mitochondria, import of proteins is complex

A

double - membrane

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9
Q

Mitochondria -
Proteins are targeted to the matrix by _____ - _______ sequences (presequences) that are removes by proteolytic cleavage after import

A

amino - terminal

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10
Q

Mitochondria -
2. _______ bind to receptors on the mitochondria that are part of a ______ complex (translocase of the outer membrane, or ____ complex)

A

Presequences
protein
Tom

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11
Q

Mitochondria -
3. Proteins are then transferred to another complex in the inner membrane (translocase of the inner membrane , or ____ complex)

A

Tim

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12
Q

Mitochondria -

Some proteins cross the matrix via ____ ; others exit laterally and are inserted into the inner membrane

A

Tim23

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13
Q

Mitochondria -

Protein translocation requires the ________ potential across the inner membrane during _______ transport

A

electrochemical

electron

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14
Q

Mitochondria -

Proteins must be _____ and require _____ chaperones

A

unfolded

Hsp70

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15
Q

Mitochondria -
Presequences are cleaved by ______ processing _______ (MPP) and the polypeptide is bound by other Hsp70 chaperones that facilitate ______

A

matrix
peptidase
folding

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16
Q

Mitochondria -

Some proteins with multiple trans- membrane domains have ______ import ______ instead of presuequences

A

internal

signals

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17
Q

Mitochondria -
After translocation across the outer membrane, they are bound by mobile _____ - ______ chaperones, which bring them to _____. The protein is transferred ______ to the _____ membrane

A

Tim9 - Tim10
Tim22
laterally
inner

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18
Q

Mitochondria -
1. Somme inner membrane proteins are encoded by the ________ _______
They are synthesized on ______ in the mitochondrial matrix and targeted to the ____ _________ in the inner membrane
The exit Oxa laterally to insert into the inner membrane

A

mitochondrial genome
ribosomes
Oxa translocase

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19
Q

Mitochondria -
2. Proteins designed for the outer membrane or ________ space also pass through the Tom complex
Proteins with ______ transmembrane domains are inserted via the outer membrane protein ______

A

intermembrane
single
Mim1

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20
Q

Mitochondria -
3. _____ - ______ proteins pass through Tom, are bound by Tim9 - Tim10 and carried to another translocon called the ____ (soting and assembly machinery)
SAM mediates their insertion into the outer membrane

A

Beta - barrel

SAM

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21
Q

Mitochondria -

Mitochondria catalyze synthesis of the _______ cardiolipin

A

phospholipid

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22
Q

Mitochondria -

Cardiolipin improves _______ of oxidative phosphorylation by _______ proton flow across the membrane

A

efficiency

restricting

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23
Q

Mitochondria -

Lipid transfer between Er and mitochondria is mediated by _______ ______ _______

Study These Flashcards
A

phospholipid transfer proteins

24
Q

Mitochondria -

The lipids are transported through the _______ and released at a new _______, such as that of mitochondria

Study These Flashcards
A

cytosol

membrane

25
Mitochondria - | Many small molecules, such as ATP, ADP, and Pi must be ______ __ and _____ of the mitochondria
moved in and out
26
Mitochondria - Energy is provided by the electrochemical gradient generated by _____ pumping across the inner mitochondrial membrane during oxidative phophorylation
proton
27
Mitochondria - 1. Transport of ___ and ____ is mediated by an integral membrane protein, the _____ nucleotide translocator One molecule of ADP moves into the _______ in exchange for ___ molecule of ATP transferred to the cytosol ATP carries a more ______ charge than ADP (-4 compared to -3), so exchange is driven by the _______ component of the electrochemical gradient
``` ATP ADP adenine mitochondrion one negative voltage ```
28
Mitochondria - 2. Pi is brought in as ______ (H2PO4-) in exchange for hydroxyl ions (OH-) This exchange is ______ ______, but is driven by the proton concentration gradient
phosphate electrically neutral
29
Mitochondria - 3. Higher pH within mitochondria corresponds to a ______ concentration of hydroxyl ions, favoring their trasnlocation to the ______
higher | outside
30
Chloroplasts - | 1. Chloroplasts:
the organelles responsible for photosynthesis.
31
Chloroplasts - True/False Chloroplasts are similar to mitochondria
``` True: They are similar in many ways: Both generate metabolic energy Evolved by endosymbiosis Contain their own genetic systems Replicate by division ```
32
Chloroplasts - 2. Chloroplasts are ______ and more complex They convert CO2 to _________; plus synthesize amino acids, fatty acids, and lipid components of their own membranes ______ (NO2-) _______ to ammonia (NH3), essential for incorporation of N into organic compounds, also occurs here
larger carbohydrates Nitrite reduction
33
Chloroplasts - | 1. Chloroplasts are bounded by a ______ _________ - the chloroplast envelope
double membrane
34
Chloroplasts - 2. An internal membrane systems, the ________ ________, forms a network of flattened discs (_______), which are frequently arranged in stacks called _______
thylakoid membrane thylakoids grana
35
Chloroplasts - 1. Chloroplasts have three internal compartments: _____________ space between the two membranes of the envelope ______ : inside the envelope but outside the thylakoid membrane _________ ________
Intermembrane Stroma Thylakoid lumen
36
Choroplasts - 2. Chloroplast membranes are ______ similar to those of mitochondria The _____ membrane contains ______ and is freely permeable to small molecules The _____ membrane is impermeable to ions and _______, which must move through specific transporters.
``` functionally outer porins inner metabolites ```
37
Chloroplasts - | The _____ is equivalent in function to the _________ matrix
stroma | mitochondrial
38
Chloroplasts - Stroma It contains the ______ system and _______ enzymes, including those needed to convert CO2 to carbohydrates during photosynthesis.
genetic | metabolic
39
Chloroplasts - | Electron transport and __________ generation of ATP takes place in the _______ membrane
chemiosmotic | thylakoid
40
Chloroplasts - | Protons are pumped across this membrane from the _____ to the ______ lumen
stroma | thylakoid
41
Chloroplasts - | The thylakoid membrane is thus equivalent to the _____ membrane of the mitocjomdria
inner
42
Chloroplasts - | 1. The chloroplast genetic system reflects the _________ origin from photosynthetic bactria
evolutionary
43
Chloroplasts - | 2. _______ DNA molecules are present in ________ copies, but are larger and more complex than those of mitochondria
Circular | multiple
44
Chloroplasts - | 3. The genes encoded in both _____ and ______ involved gene expression and photosynthesis
RNAs | proteins
45
Chloroplasts - | 4. Chloroplast tRNAs are sufficient to translate all the _____ codons using the _______ genetic code
mRNA | universal
46
Chloroplasts - 1. One subunit of ______ is encoded by chloroplast DNA Rubisco _______ addition of CO2 to ribulose - 1, 5 - bisphosphate in the ______ cycle Rubisco is critical for ________, and it is thought to e the single most abundant ______ on Earth
``` Rubisco catalyzes Calvin photosynthesis protein ```
47
Chloroplasts - | 2. Other proteins are _______ on _____ ribosomes and imported into chloroplasts as completed polypeptides
synthesized | free
48
Chloroplasts - _ - _____ sequences (transit peptides), direct translocation across the two membranes of the envelope and are then removed by _______cleavage
N - terminal | proteolytic
49
Chloroplasts - | Transit peptides direct ______ to the translocase of the chloroplast outer membrane (the ___ ______)
proteins | Toc complex
50
Chloroplasts - | Hsp70 molecules keep the polypeptide in an ________ state. Some also hydrolyze ___), providing energy for translocation
unfolded | GTP
51
Chloroplasts - Proteins then enter the Tic complex on the _____ membrane and are transported to the _____, drawn by action of an Hsp93 chaperone
inner | stroma
52
In the stroma, the transit peptide is cleaved by _______ _______ ________ (SPP)
stromal processing peptidase
53
Chloroplasts - Proteins that must cross the thylakoid membrane have a _______ ______ sequence, exposed after cleavage of the transit peptide.
second signal
54
Chloroplasts - Proteins are translocated into the thylakoid lumen by two different pathways: 1. _____ 2. _____
1. Sec pathway | 2. Tat (twin - arginine translocation)
55
Chloroplasts - 1. Sec pathway: ATP - _______ ; signal sequence is recognized by _____ protein Protein is translocated as as an ______ protein through the Sec translocon
dependent SecA unfolded
56
Chloroplasts - 2. Tat (twin- arginine translocation): Proteins have a twin - arginie signal sequence: translocated in fully - ______ state Energy comes from the _____ _______ Signal sequences are cleaves by ______ ________ ________ (TPP)
folded proton gradient thylakoid processing protease

Molecular Cell Biology (17 decks)

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