Test 3 - Lecture 24 Flashcards
Lysosomes:
membrane - enclosed organelles that contain enzymes to break down all types of biological polymers.
Lysosomes are the ______ system of the cell
diestive
Lysosomes can vary in _____ and _____ depending on the materials that have been taken up for ______.
size
shape
digestion
Lysosomes contain about ___different degradative enzymes
60
Mutations n genes that encode these enzymes result in _____ _____ ______ - undergraded material accumulated in the lysosomes of affected individuals
lysosomal
storage
diseases
______ ______ : The enzyme deficiency in ______ ______ prevents the hydrolysis of __________ to glucose and ceramide.
Gaucher Disease
Gaucher Disease
glucosylceramide
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 _________.
macrophages
phagocytosis
Most lysosomal enzymes are ____ _______ - active at pH 5 in lysosomes, but not in the _______ (pH 7.2)
acid hydrolases
cytoplasm
This prevents uncontrolled digestion of cell contents if the _______ ________ breaks down.
lysosome membrane
To maintain the acidic pH, a ______ ______ in the lysosomal membrane actively transports protons into the lysosome.
proton pump
Lysosomes digest material taken up from outside the cell by _______
endocytosis
Lysosomes are formed when transport vesicles from the ____ - _____ network fuse with a late endosome.
trans - Golgi
Three types of endosomes: ______, _______, and ______ endosomes
early
recycling
late
Early endosomes receive _______ vesicles directly from the plasma memebrane
endocytic
They separate molecules targeted for ______ from those destines for _______ in lysosomes.
reclycling
degradation
The molecules to be recycled are passed to ______ endosomes and back to the plasma membrane
recycling
Molecules destined for degradation are transported to mulitvesicular bodies ad then to ______ endosomes
late
Transport vesicles carrying ____ ______ from the trans - Golgi network then fuse with late endosomes, which mature into _______
acid hydrolases
lysosomes
____ _______ 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
Acid hydrolases
clathrin - coated
Phagocytosis:
specialized cells such as macrophages take up and degrade large particles, including bacteria, cell debris , and aged cells.
The particles are taken up in phagocytic vacuoles (__________), which fuse with lysosomes to become __________
phagosomes
phagolysosomes
Autophagy:
turnover of the cell’s own componenets
Autophagy -
Important in embryonic development and programmed cell _____
death
A small area of cytoplasm or organelle is enclosed in a vesicle (_________) which fuses with a lysosome, and its contents are digested
autophagosome
Autophagy leads to continuous ________ of cellular constituents
turnover
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
stress
starvation
reutilized
- The generation of ________ energy is a major activity of all cells
metabolic
- _______ generate energy from breakdown of lipids and carbohydrates
Mitochondria
- _______ use sunlight energy to generate ATP and reducing power to synthesize carbohydrates form CO2 and H2O
Choloropasts
- _______ contain enzymes involved in a variety of metabollic
Peroxisomes
Mitochondria, Chloroplasts and Peroxisomes -
Proteins are synthesized on _____ ribosomes and imported to these organelles as completed ________
free
polypeptides
- Mitochondria and chloroplasts also have their own _______, including some genes that are transcribed and translated within the organelle
genomes
- Mitochondria are surrounded by a _______ - ________ system
double - membrane
Mitochondria -
Inner and outer membranes are separated by an _________ space
intermembrane
Mitochondria -
The inner membrane has numerous folds (______), which extend into the interior (______)
cristae
matrix
Mitochondria -
1. The matrix : contains _______ system and ______ for oxidative metabolism
genetic
enzymes
Mitochondria -
2. _______ (form glycolysis) is transported to mitochondria, (1) complete oxidation to CO2; (2) yields the bulk of energy (ATP)
Pyruvate
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 _______ ________
matrix
oxidation
glucose metabolism
Glycolysis takes place in the ______
cytosol
In eukaryotic cells, pyruvate is then transported into ________, where it is completely oxidized
mitochondria
Pyruvate undergoes oxidative decarboxylation in the presense of ______ _ (____ - __), forming ______ ____; generation of _____
coenzyme A (CoA - SH)
acetyl CoA
2NADH
Acetyl CoA enter the ____ _____ cycle (_____ cycle)
citric acid
Krebs
The 2 - carbon acetyl group combines with oxaloacetate ( ___ carbons) to yield ____ ( 6 carbons)
4
citrate
In the remaining reactions, 2 carbons of citrate are completely ______ to CO2 and oxaloacetate is _______
oxidized
regenerated
2 carbons of citrate:
2 CO2 1 oxaloacetate 1 GTP 3 NADH and 1 FADH2
Oxidation of glucose:
6 molecules of CO2, 4 ATP, 10 NADH, 2 FADH2
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
2 ATP
8 NADH
3
FADH2
- _______ _ receives _______ from the citric acid cycle intermediate succinate
Complex II
electrons
- These electrons are transferred to FADH2, rather than NADH, and then to _______ _
coenzyme Q
True/False:
The first step of transfer does not yield free energy
True
Mitochondria -
1. The enzymes of the ____ _____ _____ are in the mitochondrial matrix
citric acid cycle
Mitochondria -
2. Most of the energy is
produced by _________ _________,
takes place in the ______ mitochondrial membrane
oxidative phosphorylation
inner
Mitochondria -
3. _____ - energy electrons form NADH and FADH2 are transferred through a series of carries in the _______ to molecular oxygen
High
membrane
Mitochondria -
4. The energy derived from this is converted to potential energy stored in a ______ ______, which drives ATP synthesis
proton gradient
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
ATP generation
folding
proteins
impermrable
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 ______
Highly
small
porins
cytosol
Mitochondria -
3. Position; often near locations of ____ - _____ use, such as synapses in nerve cells
high - energy
In most mitochondria form an ___________ network, and are constantly ______ and _______ to remodel this network, and modify mitochondrial ________ and function
interconnected
fusing
dividing
morphology
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
circular multiple oxidative phosphorylation rRNAs tRNAs
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
13 electron transport respiratory complexes 16S tRNAs
True/False:
The mitochondrial genetic code is the same form the universal code
False -
It is different
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 _____ ______
third
single tRNA
Some codons specify different amino acids in ________ than in the universal code
mitochondrua
