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Molecular Cell Biology > Test 3 - Lecture 24 > Flashcards

Test 3 - Lecture 24 Flashcards

1
Q

Lysosomes:

A

membrane - enclosed organelles that contain enzymes to break down all types of biological polymers.

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2
Q

Lysosomes are the ______ system of the cell

A

diestive

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3
Q

Lysosomes can vary in _____ and _____ depending on the materials that have been taken up for ______.

A

size
shape
digestion

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4
Q

Lysosomes contain about ___different degradative enzymes

A

60

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5
Q

Mutations n genes that encode these enzymes result in _____ _____ ______ - undergraded material accumulated in the lysosomes of affected individuals

A

lysosomal
storage
diseases

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6
Q

______ ______ : The enzyme deficiency in ______ ______ prevents the hydrolysis of __________ to glucose and ceramide.

A

Gaucher Disease
Gaucher Disease
glucosylceramide

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7
Q

Gaucher Disease:
In the most common form of the disease, _____ are the only cells affected. Their function is to eliminate aged and damaged cells by _________.

A

macrophages

phagocytosis

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8
Q

Most lysosomal enzymes are ____ _______ - active at pH 5 in lysosomes, but not in the _______ (pH 7.2)

A

acid hydrolases

cytoplasm

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9
Q

This prevents uncontrolled digestion of cell contents if the _______ ________ breaks down.

A

lysosome membrane

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10
Q

To maintain the acidic pH, a ______ ______ in the lysosomal membrane actively transports protons into the lysosome.

A

proton pump

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11
Q

Lysosomes digest material taken up from outside the cell by _______

A

endocytosis

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12
Q

Lysosomes are formed when transport vesicles from the ____ - _____ network fuse with a late endosome.

A

trans - Golgi

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13
Q

Three types of endosomes: ______, _______, and ______ endosomes

A

early
recycling
late

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14
Q

Early endosomes receive _______ vesicles directly from the plasma memebrane

A

endocytic

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15
Q

They separate molecules targeted for ______ from those destines for _______ in lysosomes.

A

reclycling

degradation

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16
Q

The molecules to be recycled are passed to ______ endosomes and back to the plasma membrane

A

recycling

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17
Q

Molecules destined for degradation are transported to mulitvesicular bodies ad then to ______ endosomes

A

late

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18
Q

Transport vesicles carrying ____ ______ from the trans - Golgi network then fuse with late endosomes, which mature into _______

A

acid hydrolases

lysosomes

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19
Q

____ _______ are targeted to late endosomes by mannose - 6 - phosphate residues, whic are recognozed by mannose - 6 - phosphate receptors in the trans Golgi network ans packaged into _____ - _____ vesicles

A

Acid hydrolases

clathrin - coated

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20
Q

Phagocytosis:

A

specialized cells such as macrophages take up and degrade large particles, including bacteria, cell debris , and aged cells.

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21
Q

The particles are taken up in phagocytic vacuoles (__________), which fuse with lysosomes to become __________

A

phagosomes

phagolysosomes

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22
Q

Autophagy:

A

turnover of the cell’s own componenets

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23
Q

Autophagy -

Important in embryonic development and programmed cell _____

A

death

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24
Q

A small area of cytoplasm or organelle is enclosed in a vesicle (_________) which fuses with a lysosome, and its contents are digested

A

autophagosome

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25
Q

Autophagy leads to continuous ________ of cellular constituents

A

turnover

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26
Q

Autophagy -
It can also be regulated during development in response to ______
It nutrient _______ occurs, autophagy degrades nonessential macromolecules so their components can be ______
Autophagy also plays an important role in programmed cell death

A

stress
starvation
reutilized

27
Q
  1. The generation of ________ energy is a major activity of all cells
A

metabolic

28
Q
  1. _______ generate energy from breakdown of lipids and carbohydrates
A

Mitochondria

29
Q
  1. _______ use sunlight energy to generate ATP and reducing power to synthesize carbohydrates form CO2 and H2O
A

Choloropasts

30
Q
  1. _______ contain enzymes involved in a variety of metabollic
A

Peroxisomes

31
Q

Mitochondria, Chloroplasts and Peroxisomes -

Proteins are synthesized on _____ ribosomes and imported to these organelles as completed ________

A

free

polypeptides

32
Q
  1. Mitochondria and chloroplasts also have their own _______, including some genes that are transcribed and translated within the organelle
A

genomes

33
Q
  1. Mitochondria are surrounded by a _______ - ________ system
A

double - membrane

34
Q

Mitochondria -

Inner and outer membranes are separated by an _________ space

A

intermembrane

35
Q

Mitochondria -

The inner membrane has numerous folds (______), which extend into the interior (______)

A

cristae

matrix

36
Q

Mitochondria -

1. The matrix : contains _______ system and ______ for oxidative metabolism

A

genetic

enzymes

37
Q

Mitochondria -
2. _______ (form glycolysis) is transported to mitochondria, (1) complete oxidation to CO2; (2) yields the bulk of energy (ATP)

A

Pyruvate

38
Q

Mitochondria -
3. The enzymes of the citric acid cycle are in the mitochondrial _____
Glycolysis occurs in the cytosol: pyruvate is transported into mitochondria, where its complete _______ to CO2 yields the bulk of usable energy (ATP) obtained from _______ ________

A

matrix
oxidation
glucose metabolism

39
Q

Glycolysis takes place in the ______

A

cytosol

40
Q

In eukaryotic cells, pyruvate is then transported into ________, where it is completely oxidized

A

mitochondria

41
Q

Pyruvate undergoes oxidative decarboxylation in the presense of ______ _ (____ - __), forming ______ ____; generation of _____

A

coenzyme A (CoA - SH)
acetyl CoA
2NADH

42
Q

Acetyl CoA enter the ____ _____ cycle (_____ cycle)

A

citric acid

Krebs

43
Q

The 2 - carbon acetyl group combines with oxaloacetate ( ___ carbons) to yield ____ ( 6 carbons)

A

4

citrate

44
Q

In the remaining reactions, 2 carbons of citrate are completely ______ to CO2 and oxaloacetate is _______

A

oxidized

regenerated

45
Q

2 carbons of citrate:

A 
2 CO2
1 oxaloacetate
1 GTP
3 NADH and
1 FADH2
46
Q

Oxidation of glucose:

A

6 molecules of CO2, 4 ATP, 10 NADH, 2 FADH2

47
Q

Total ATP yields from oxidation of glucose: 38 ( in some cells 36)
Glycolysis: _ ____ + 2 NADH
Citric acid cycle: 2 ATP + _ _____ + 2 FADH2
Oxdative phophorylation: each NADH yields _ ATP, each _____ yields 2 ATP
Total: 2 ATP + 2 ATP + 103 (NADH) + 22 (FADH2) = 38

A

2 ATP
8 NADH
3
FADH2

48
Q
  1. _______ _ receives _______ from the citric acid cycle intermediate succinate
A

Complex II

electrons

49
Q
  1. These electrons are transferred to FADH2, rather than NADH, and then to _______ _
A

coenzyme Q

50
Q

True/False:

The first step of transfer does not yield free energy

A

True

51
Q

Mitochondria -

1. The enzymes of the ____ _____ _____ are in the mitochondrial matrix

A

citric acid cycle

52
Q

Mitochondria -
2. Most of the energy is
produced by _________ _________,
takes place in the ______ mitochondrial membrane

A

oxidative phosphorylation

inner

53
Q

Mitochondria -
3. _____ - energy electrons form NADH and FADH2 are transferred through a series of carries in the _______ to molecular oxygen

A

High

membrane

54
Q

Mitochondria -

4. The energy derived from this is converted to potential energy stored in a ______ ______, which drives ATP synthesis

A

proton gradient

55
Q

Mitochondria -
1. The inner membrane
The principal site of ____ _______
Surface area is increased by _______ into cristae
Contains a high percentage of _______ involved in oxidative metabolism and transport
________ to most ions and small molecules - this helps maintain the proton gradient

A

ATP generation
folding
proteins
impermrable

56
Q

Mitochondria -
2. The outer mitochondrial membrane
______ permeable to ______ molecules
Contains _______, which form channels that allow the free diffusion of small molecules
Composition of the intermembrane space is similar to the ______

A

Highly
small
porins
cytosol

57
Q

Mitochondria -

3. Position; often near locations of ____ - _____ use, such as synapses in nerve cells

A

high - energy

58
Q

In most mitochondria form an ___________ network, and are constantly ______ and _______ to remodel this network, and modify mitochondrial ________ and function

A

interconnected
fusing
dividing
morphology

59
Q

Mitochondrial genomes
usually ______ DNA molecules, present in ________ copies
encode only a few proteins that are essential for ________ __________
encode all the _____ and most of the _____ needed for translating the protein - coding sequences

A 
circular
multiple
oxidative phosphorylation
rRNAs
tRNAs
60
Q

The human mitochondrial genome
encodes __ proteins involved in _______ _______ and oxidative phosphorylation
The sequences are designed as _________ ________ I, II, III, IV or V
Plus ___ and 12S rRNAs; and 22 _____, which are required for translation of the proteins

A 
13
electron transport
respiratory complexes
16S
tRNAs
61
Q

True/False:

The mitochondrial genetic code is the same form the universal code

A

False -

It is different

62
Q

U in the tRNA anticodon can pair with any of the four bases in the ____ codon position of mRAN; thus four codons are recognized by a _____ ______

A

third

single tRNA

63
Q

Some codons specify different amino acids in ________ than in the universal code

A

mitochondrua

Molecular Cell Biology (17 decks)

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