SfC - PASTE Flashcards
(199 cards)
1
Q
What is a mitochondrion?
A
An organelle found in the cells of most eukaryotes, such as animals, plants, and fungi.
2
Q
What is the primary function of mitochondria?
A
To generate adenosine triphosphate (ATP) through aerobic respiration.
3
Q
Who discovered mitochondria and in what year?
A
Albert von Kölliker in 1857.
4
Q
What does the term ‘mitochondrion’ mean?
A
A thread-like granule.
5
Q
Who coined the term ‘mitochondrion’?
A
Carl Benda in 1898.
6
Q
What nickname is commonly used for mitochondria?
A
“Powerhouse of the cell.”
7
Q
True or False: All multicellular organisms have mitochondria in every cell.
A
False.
8
Q
Which multicellular organism is known to have retained mitochondrion-related organelles despite losing its mitochondrial genome?
A
Henneguya salminicola.
9
Q
What is the size range of mitochondria?
A
Between 0.75 and 3 μm² in cross section.
10
Q
What are the five distinct parts of a mitochondrion?
A
- Outer mitochondrial membrane
- Intermembrane space
- Inner mitochondrial membrane
- Cristae
- Matrix
11
Q
What is the outer mitochondrial membrane composed of?
A
Phospholipid bilayers and proteins.
12
Q
What is the primary transporter of nucleotides, ions, and metabolites in the outer mitochondrial membrane?
A
Voltage-dependent anion channel (VDAC).
13
Q
What are porins?
A
Integral membrane proteins found in the outer mitochondrial membrane.
14
Q
What is the intermembrane space?
A
The space between the outer membrane and the inner membrane.
15
Q
What is the primary function of the inner mitochondrial membrane?
A
Contains proteins for the electron transport chain, ATP synthase, and metabolite transport.
16
Q
What is cardiolipin?
A
An unusual phospholipid rich in the inner mitochondrial membrane.
17
Q
What is the function of cristae in mitochondria?
A
To increase surface area for ATP production.
18
Q
What is contained in the mitochondrial matrix?
A
- Enzymes
- Mitochondrial ribosomes
- tRNA
- Mitochondrial DNA
19
Q
What cycle is involved in ATP production in mitochondria?
A
Citric acid cycle (Krebs cycle).
20
Q
What type of respiration do mitochondria primarily use?
A
Aerobic respiration.
21
Q
What is the role of pyruvate in the mitochondria?
A
It is oxidized to form acetyl-CoA and NADH.
22
Q
What happens to acetyl-CoA in the citric acid cycle?
A
It is oxidized to produce CO2 and ATP.
23
Q
What are the major energy-releasing reactions in mitochondria associated with?
A
Protein complexes I, III, and IV in the inner mitochondrial membrane.
24
Q
Fill in the blank: The mitochondrial DNA is similar to _______.
A
[bacterial genomes].
25
What are the main products of the citric acid cycle?
* CO2
* NADH
* FADH2
* GTP (converted to ATP)
26
What is the relationship between the citric acid cycle and ATP production?
The cycle produces reducing equivalents for the electron transport chain, leading to ATP generation.
27
True or False: The inner mitochondrial membrane is highly permeable to all molecules.
False.
28
What is the significance of the endosymbiotic hypothesis?
It suggests that mitochondria evolved from free-living prokaryotic ancestors.
29
What is an anaplerotic reaction in the context of the citric acid cycle?
A reaction that increases the amount of cycle intermediates.
30
What is the role of the electron transport chain?
To transfer electrons from NADH and FADH2 to oxygen, releasing energy.
31
What are the protein complexes involved in energy-releasing reactions in mitochondria?
Complexes I, III, and IV
## Footnote
These include NADH dehydrogenase (ubiquinone), cytochrome c reductase, and cytochrome c oxidase.
32
What is the reaction at complex IV in the electron transport chain?
O2 + 4H+ (aq) + 4Fe2+ (cyt c) ⟶ 2H2O + 4Fe3+ (cyt c)
## Footnote
The ΔrGo' for this reaction is -218 kJ/mol.
33
What is the significance of the free energy released during mitochondrial reactions?
It is used to pump protons (H+) into the intermembrane space.
34
What is chemiosmosis?
The process where protons return to the matrix through ATP synthase, synthesizing ATP from ADP and Pi.
35
Who first described chemiosmosis?
Peter Mitchell.
36
What is mitochondrial uncoupling?
Protons re-enter the mitochondrial matrix without contributing to ATP synthesis, releasing energy as heat.
37
What protein mediates proton leak in mitochondria?
Thermogenin (UCP1).
38
What is the main product of mitochondrial fatty acid synthesis (mtFASII)?
Octanoyl-ACP (C8).
39
What role does mitochondrial fatty acid synthesis play in metabolism?
It is essential for cellular respiration and mitochondrial biogenesis.
40
How do mitochondria regulate intracellular calcium levels?
They can transiently store calcium and act as cytosolic buffers.
41
What protein allows calcium uptake into the mitochondrial matrix?
Mitochondrial calcium uniporter.
42
What is the role of calcium in mitochondrial bioenergetics?
It helps regulate the electrochemical potential across the membrane.
43
How does ATP production relate to cellular proliferation?
Tumor cells require ATP for rapid proliferation, primarily generated via oxidative phosphorylation.
44
What is programmed cell death (PCD)?
A mechanism crucial for organ development and cellular homeostasis.
45
What role do mitochondria play in apoptosis?
They release cytochrome c, which induces the formation of apoptosomes.
46
What are damage-associated molecular patterns (DAMPs)?
Mitochondrial elements that can trigger immune responses.
47
What is the mitochondrial-associated ER membrane (MAM)?
A structure that plays a critical role in cellular physiology and homeostasis.
48
What is the estimated percentage of the mitochondrial outer membrane comprising the MAM?
Up to 20%.
49
What is the relationship between mitochondria and the endoplasmic reticulum?
They are physically coupled at the MAM, facilitating lipid exchange and calcium signaling.
50
What is the role of mitochondrial reactive oxygen species?
They are involved in signaling processes within the cell.
51
What types of metabolic tasks do mitochondria perform?
Regulation of membrane potential, calcium signaling, steroid synthesis, and more.
52
How do mitochondrial proteins vary?
They vary depending on the tissue and species.
53
What is the chondriome?
The population of all the mitochondria of a given cell.
54
What cellular structures determine the shape and distribution of mitochondria?
Microtubules and the cytoskeleton.
55
What is the significance of mitochondrial dynamics such as fission and fusion?
They allow mitochondria to form a highly dynamic network.
56
What does MAM stand for?
Mitochondria-associated membranes
## Footnote
MAM plays a critical role in cellular physiology and mitochondrial function.
57
What physiological processes does the MAM provide insight into?
* Intrinsic apoptosis
* Propagation of calcium signaling
## Footnote
These processes highlight the importance of MAM in cell survival and signaling.
58
What role does the MAM play in lipid biosynthesis?
Enriched in enzymes such as phosphatidylserine synthase and phosphatidylserine decarboxylase
## Footnote
These enzymes are crucial for maintaining mitochondrial membrane integrity.
59
How do mitochondria receive phospholipids?
Through inter-organelle trafficking and lipid transfer facilitated by the MAM
## Footnote
Mitochondria are dynamic and require a constant supply of phospholipids.
60
What is the mechanism of lipid transfer at the MAM?
Lipid flipping between opposed bilayers due to close proximity of ER and mitochondrial membranes
## Footnote
This process is energy-efficient and does not require ATP.
61
What is the role of the ER-mitochondria encounter structure (ERMES)?
Facilitates lipid transfer and maintains close membrane proximity
## Footnote
Its exact role in lipid transfer remains under investigation.
62
What is VLDL?
Very-low-density lipoprotein
## Footnote
MAM is an intermediate destination in VLDL assembly and secretion.
63
What is the role of the MAM in calcium signaling?
Facilitates efficient Ca2+ transmission from the ER to mitochondria
## Footnote
The close physical association between ER and mitochondria allows for Ca2+ microdomains.
64
What are Ca2+ puffs?
Spontaneous clustering and activation of IP3R at the ER membrane
## Footnote
They are crucial for the transmission of calcium signals to mitochondria.
65
How does the MAM buffer Ca2+ puffs?
Acts as a sink for free ions released into the cytosol
## Footnote
This buffering helps in regulating calcium levels and preventing excessive exposure to mitochondria.
66
What is SERCA?
Sarcoplasmic reticulum Ca2+ ATPase
## Footnote
It regulates calcium uptake into the ER and is influenced by mitochondrial feedback.
67
What is the significance of calcium signaling in mitochondria?
Stimulates metabolism and can trigger intrinsic apoptosis if threshold is exceeded
## Footnote
Proper regulation is crucial for cellular homeostasis.
68
What is the CoRR hypothesis?
Proposes that co-location of mitochondrial DNA and respiratory chain proteins is necessary for redox regulation
## Footnote
This highlights the functional integration of mitochondria in cellular metabolism.
69
What is the endosymbiotic hypothesis?
Suggests that mitochondria originated from prokaryotic cells that became endosymbionts in eukaryotic cells
## Footnote
This theory is widely accepted due to similarities between mitochondria and bacteria.
70
How many genes does the human mitochondrial genome encode?
37 genes
## Footnote
These include genes for subunits of respiratory complexes and tRNAs.
71
What is the structure of mitochondrial DNA?
Circular double-stranded DNA molecule
## Footnote
The human mitochondrial genome is approximately 16 kilobases long.
72
What are the two strands of mitochondrial DNA called?
* Heavy strand (H strand)
* Light strand (L strand)
## Footnote
The H strand has a higher ratio of adenine and guanine.
73
What are hydrogenosomes and mitosomes?
Organelles derived from mitochondria found in some unicellular eukaryotes
## Footnote
They represent vestigial forms of mitochondria.
74
What is the role of mitochondrial ribosomes?
Similar in size and structure to bacterial ribosomes
## Footnote
They are involved in the translation of mitochondrial mRNAs.
75
What is the significance of the endosymbiotic relationship?
Provided evolutionary advantages by allowing aerobic respiration in eukaryotic cells
## Footnote
This relationship likely developed 1.7 to 2 billion years ago.
76
What is the typical structure of the mitochondrial genome in animals?
A single circular chromosome approximately 16 kb long with 37 genes
## Footnote
This structure may vary, as seen in the human body louse, which has 18 minicircular chromosomes.
77
How does mitochondrial DNA contribute to human population genetics?
It is inherited as a single unit (haplotype) and can represent relationships through gene trees
## Footnote
This allows the inference of evolutionary history, such as the concept of mitochondrial Eve.
78
What does the term 'molecular clock' refer to in mitochondrial genetics?
The rate of mutations in mitochondrial DNA over time, used to estimate dates for common ancestors
## Footnote
For example, a mutation rate of 1 every 7884 years.
79
What are some exceptions to the standard genetic code observed in mitochondria?
Variations include:
* AGA, AGG codons as stop codons in mammals
* CUA codon as threonine in fungi
* UGA as tryptophan in some organisms
## Footnote
These variations can lead to pseudo-changes due to RNA editing.
80
What is mitochondrial fission?
A form of binary fission where mitochondria divide, regulated by the host eukaryotic cell
## Footnote
This process involves communication with other organelles and can occur in response to the cell's energy needs.
81
From whom are mitochondrial genes typically inherited?
Only from the mother
## Footnote
In humans, paternal mitochondria are usually marked for destruction after fertilization.
82
What is the mtDNA bottleneck?
A developmental process that increases variability in mutant load among cells during development
## Footnote
It helps avoid the accumulation of deleterious mutations in mitochondrial DNA.
83
How do mitochondria repair oxidative DNA damage?
Through pathways like base excision repair, double-strand break repair, direct reversal, and mismatch repair
## Footnote
Proteins for repair are encoded by nuclear genes and transported to mitochondria.
84
Which organisms have lost their mitochondrial DNA?
Cryptosporidium and some dinoflagellates such as A. cerati
## Footnote
These organisms have adapted their metabolism to function without mitochondrial DNA.
85
What are some diseases caused by mitochondrial dysfunction?
Conditions include:
* Kearns–Sayre syndrome
* MELAS syndrome
* Leber's hereditary optic neuropathy
## Footnote
Mitochondrial disorders can manifest as neurological disorders, among others.
86
What role do mitochondria play in aging?
They are linked to oxidative stress and mitochondrial DNA mutations, contributing to age-related dysfunction
## Footnote
The mitochondrial free radical theory of aging suggests a vicious cycle of damage and dysfunction.
87
Fill in the blank: Mitochondrial replacement therapy (MRT) uses _______ to avoid transmission of mitochondrial diseases.
[donor mitochondria]
88
What effect does mitochondrial dysfunction have on cardiac efficiency in type 2 diabetics?
It leads to reduced ATP synthesis and energy deficit, causing contractile dysfunction
## Footnote
Increased reactive oxygen species can also contribute to this dysfunction.
89
True or False: Mitochondria can be inherited from both parents.
False
## Footnote
Mitochondrial DNA is typically inherited only from the mother.
90
What is the significance of mitochondrial dynamics?
It involves the balance between mitochondrial fusion and fission, impacting various diseases
## Footnote
Dysregulation can contribute to pathologies associated with mitochondrial dysfunction.
91
What is the primary mechanism of repair for oxidative DNA damage in mitochondria?
Base excision repair
## Footnote
This pathway involves several enzyme-catalyzed steps to correct damaged DNA.
92
What pivotal role do mitochondria play in ovarian function?
Providing ATP necessary for the development from germinal vesicle to mature oocyte
93
What can decreased mitochondrial function lead to in the context of ovarian health?
Inflammation, resulting in premature ovarian failure and accelerated ovarian aging
94
What are the three types of dysfunction reflected in mitochondrial issues?
* Quantitative (mtDNA copy number and mtDNA deletions)
* Qualitative (mutations and strand breaks)
* Oxidative damage (dysfunctional mitochondria due to ROS)
95
What genetic disorder is linked to mitochondrial dysfunction in ovarian aging?
Fragile X
96
Who published the first observations of structures that likely represented mitochondria?
Albert von Kolliker in 1857
97
What term did Carl Benda coin for mitochondria, and what does it derive from?
'Mitochondria', derived from Greek μίτος (mitos, 'thread') and χονδρίον (chondrion, 'granule')
98
In what year did Leonor Michaelis discover a supravital stain for mitochondria?
1900
99
What significant observation did Friedrich Meves make in 1904?
The first recorded observation of mitochondria in plant cells
100
What did Benjamin F. Kingsbury relate mitochondria to in 1912?
Cell respiration
101
Who linked respiration to particles obtained from guinea-pig liver in 1913?
Otto Heinrich Warburg
102
What discovery did David Keilin make in 1925?
He discovered cytochromes and described the respiratory chain
103
What did experiments in 1939 demonstrate about cellular respiration?
Using one oxygen molecule can form four ATP molecules
104
Who developed the concept of phosphate bonds of ATP being a form of energy in cellular metabolism?
Fritz Albert Lipmann in 1941
105
What important technique did Albert Claude introduce for studying mitochondria?
Tissue fractionation
106
What did Eugene Kennedy and Albert Lehninger discover in 1948?
Mitochondria are the site of oxidative phosphorylation in eukaryotes
107
What advancement in microscopy occurred in 1952 regarding mitochondria?
The first high-resolution electron micrographs appeared
108
What popular term was coined by Philip Siekevitz in 1957?
Powerhouse of the cell
109
What significant discovery was made about mitochondria in 1967?
Mitochondria contained ribosomes
110
When was the genetic and physical map of yeast mitochondrial DNA completed?
1976
111
What discovery was made by researchers in November 2024 regarding mitochondria?
Mitochondria divide into two distinct forms when cells are starved
112
What is a mitochondrion?
An organelle found in the cells of most eukaryotes, involved in aerobic respiration and ATP generation
## Footnote
Mitochondria are often referred to as the 'powerhouse of the cell'.
113
Who discovered mitochondria and when?
Albert von Kölliker in 1857
## Footnote
He discovered them in the voluntary muscles of insects.
114
What is the term 'mitochondrion' derived from?
A thread-like granule
## Footnote
The term was coined by Carl Benda in 1898.
115
What is the main function of mitochondria?
To generate ATP through aerobic respiration
## Footnote
They also play roles in signaling, cellular differentiation, and cell death.
116
What is the typical size range of mitochondria?
0.75 to 3 μm² in cross section
## Footnote
Their size can vary considerably.
117
What are the compartments of a mitochondrion?
* Outer membrane
* Intermembrane space
* Inner membrane
* Cristae
* Matrix
118
What is the outer mitochondrial membrane composed of?
Phospholipid bilayers and proteins
## Footnote
It has a protein-to-phospholipid ratio similar to that of the cell membrane.
119
What is the role of porins in the outer mitochondrial membrane?
They form channels that allow the passage of small molecules
## Footnote
The voltage-dependent anion channel (VDAC) is a major trafficking protein.
120
What is the purpose of the intermembrane space in mitochondria?
It serves as a compartment for certain proteins and ions
## Footnote
Its protein composition differs from that of the cytosol.
121
What type of proteins are found in the inner mitochondrial membrane?
* Proteins for electron transport chain reactions
* ATP synthase
* Specific transport proteins
122
What is cardiolipin and where is it found?
A phospholipid characteristic of mitochondrial and bacterial membranes
## Footnote
It contains four fatty acids and contributes to membrane impermeability.
123
What are cristae in mitochondria?
Folds of the inner membrane that increase surface area for ATP production
## Footnote
They are more abundant in cells with higher ATP demands.
124
What is contained within the mitochondrial matrix?
* Enzymes
* Mitochondrial ribosomes
* tRNA
* Mitochondrial DNA
125
What is the primary function of the citric acid cycle?
To oxidize acetyl-CoA and produce ATP and reduced cofactors
## Footnote
It is also known as the Krebs cycle.
126
What are the main energy-releasing reactions in mitochondria?
* Reactions at protein complexes I, III, and IV in the inner mitochondrial membrane
* Reactions involving NADH and FADH2
127
True or False: Mitochondria have their own genome.
True
## Footnote
The mitochondrial genome is similar to bacterial genomes.
128
Fill in the blank: Mitochondrial biogenesis is temporally coordinated with _______.
cellular processes
129
What is the role of the ATP synthase in mitochondria?
To generate ATP from ADP and inorganic phosphate in the matrix
## Footnote
It utilizes the proton gradient established by the electron transport chain.
130
What are the protein complexes where energy-releasing reactions occur in mitochondria?
Protein complexes I, III, and IV
## Footnote
These include NADH dehydrogenase (ubiquinone), cytochrome c reductase, and cytochrome c oxidase.
131
What is the reaction that occurs at complex IV of the electron transport chain?
O2 + 4H+ (aq) + 4Fe2+ (cyt c) ⟶ 2H2O + 4Fe3+ (cyt c)
## Footnote
ΔrGo′ = -218 kJ/mol, releasing a lot of free energy.
132
What is the reaction that occurs at complex III involving cytochrome c?
2Fe3+ (cyt c) + QH2 ⟶ 2Fe2+ (cyt c) + Q + 2H+ (aq)
## Footnote
ΔrGo′ = -30 kJ/mol.
133
What is the reaction at complex I involving NADH?
Q + H+ (aq) + NADH ⟶ QH2 + NAD+
## Footnote
ΔrGo′ = -81 kJ/mol.
134
What mechanism allows protons to return to the mitochondrial matrix and synthesize ATP?
Chemiosmosis
## Footnote
This process was first described by Peter Mitchell.
135
What is mitochondrial uncoupling or proton leak?
Protons re-enter the mitochondrial matrix without contributing to ATP synthesis
## Footnote
Mediated by the proton channel thermogenin (UCP1).
136
What is the primary end product of mitochondrial fatty acid synthesis (mtFASII)?
Octanoyl-ACP (C8)
## Footnote
It is also involved in lipoic acid biosynthesis.
137
What is the role of mitochondria in calcium ion regulation?
Mitochondria can transiently store calcium and regulate cellular calcium homeostasis
## Footnote
They act as cytosolic buffers for calcium.
138
How do mitochondria influence cellular proliferation?
Mitochondria generate ATP via oxidative phosphorylation, which is vital for cell division and differentiation
## Footnote
Interference with OxPhos can cause cell cycle arrest.
139
What is programmed cell death (PCD) and its role?
PCD is crucial for organ development and cellular homeostasis
## Footnote
It prevents malignant transformation and aids in immunity.
140
What role do mitochondria play in apoptosis?
Mitochondria release cytochrome c, which induces the formation of apoptosomes
## Footnote
They also release damage-associated molecular patterns (DAMPs).
141
What are some additional functions of mitochondria?
* Signaling through mitochondrial reactive oxygen species
* Regulation of the membrane potential
* Calcium signaling
* Regulation of cellular metabolism
## Footnote
Mitochondria are involved in heme and steroid synthesis, hormonal signaling, and immune cell development.
142
What is the chondriome?
The population of all mitochondria in a given cell
## Footnote
Mitochondria vary in number and location according to cell type.
143
What is the mitochondria-associated ER membrane (MAM)?
A structural element that plays a critical role in cellular physiology and homeostasis
## Footnote
It is the interface between mitochondria and the ER.
144
What is the significance of the physical coupling between mitochondria and the ER?
It regulates cellular lipid stores and signal transduction
## Footnote
MAM may comprise up to 20% of the mitochondrial outer membrane.
145
What is the role of the MAM in cellular physiology?
The MAM integrates mitochondria and endomembrane systems, influencing processes such as intrinsic apoptosis and calcium signaling
## Footnote
MAM stands for Mitochondria-Associated Membranes
146
What enzymes are enriched in the MAM?
Phosphatidylserine synthase and phosphatidylserine decarboxylase
## Footnote
These enzymes are involved in lipid biosynthesis
147
What is the significance of lipid transfer at the MAM?
It facilitates the transfer of lipid intermediates between organelles without requiring ATP
## Footnote
This process occurs through lipid flipping between opposed bilayers
148
What is the ER-mitochondria encounter structure (ERMES)?
A multiprotein tethering structure that may facilitate lipid transfer and maintain close proximity between ER and mitochondrial membranes
## Footnote
ERMES is crucial for lipid transfer at the MAM
149
How does the MAM function in calcium signaling?
It creates Ca2+ microdomains that facilitate efficient Ca2+ transmission from the ER to mitochondria
## Footnote
This occurs during cellular events called 'Ca2+ puffs'
150
What role does VDAC1 play at the MAM?
VDAC1 serves as a low-affinity Ca2+ receptor that aids in Ca2+ tunneling from the cytosol to mitochondria
## Footnote
VDAC1 is physically tethered to IP3R clusters on the ER membrane
151
True or False: Calcium signaling is unidirectional at the MAM.
False
## Footnote
Calcium signaling at the MAM is bidirectional, involving feedback regulation
152
What happens when Ca2+ signaling in mitochondria exceeds a certain threshold?
It stimulates the intrinsic pathway of apoptosis by collapsing the mitochondrial membrane potential
## Footnote
This process is influenced by pro- and anti-apoptotic factors such as Bcl-2
153
What are the two hypotheses regarding the origin of mitochondria?
* Endosymbiotic hypothesis
* Autogenous hypothesis
## Footnote
The endosymbiotic hypothesis is more widely accepted due to the similarities between mitochondria and prokaryotes
154
How is mitochondrial DNA structured?
It is a circular double-stranded DNA molecule containing 37 genes
## Footnote
The genes include those for respiratory complexes, tRNA, and rRNA
155
What is the significance of the heavy and light strands in mitochondrial DNA?
The heavy strand has a higher ratio of adenine and guanine, allowing separation by centrifugation
## Footnote
This difference helps in the identification of mitochondrial DNA strands
156
What are MROs and which organelles are classified as such?
* Hydrogenosomes
* Mitosomes
* Other related organelles
## Footnote
MROs are mitochondrion-related organelles found in some unicellular eukaryotes
157
What is the circular human mitochondrial genome's approximate length?
About 16 kilobases
## Footnote
This genome encodes essential genes for mitochondrial function
158
What is the role of mitochondrial tRNA compared to nuclear tRNA?
Mitochondrial tRNA has different sequences but resembles bacterial tRNA
## Footnote
This difference is crucial for mitochondrial protein synthesis
159
What is a unique feature of mitochondrial genomes in animals?
Typically a single circular chromosome approximately 16 kb long
## Footnote
This pattern differs in some species, such as the human body louse
160
What is the main function of the MAM in relation to VLDL?
It serves as an intermediate destination between the rough ER and Golgi for VLDL assembly and secretion
## Footnote
VLDL stands for very-low-density lipoprotein
161
What is the typical structure of the mitochondrial genome in animals?
A single circular chromosome that is approximately 16 kb long and has 37 genes.
162
How does the mitochondrial genome of the human body louse differ from typical animal mitochondrial genomes?
It is arranged in 18 minicircular chromosomes, each 3–4 kb long with one to three genes.
163
What is the significance of mitochondrial DNA in population genetics?
It is a useful source for studying population genetics due to its near-absence of genetic recombination.
164
What is a haplotype in the context of mitochondrial DNA?
A single unit of inherited mitochondrial DNA.
165
What does the molecular clock in mitochondrial genetics suggest about human evolution?
It supports a recent modern human expansion out of Africa.
166
What is a classic example of mitochondrial DNA studies related to human ancestry?
The sequencing of mitochondrial DNA from Neanderthal bones.
167
True or False: Mitochondrial DNA reflects both male and female ancestry.
False.
168
What is the mutation rate for mitochondrial DNA as reported in recent studies?
1 mutation every 7884 years.
169
What are some exceptions to the standard genetic code found in mitochondria?
In mammals: AGA, AGG are stop codons instead of arginine.
170
What process do mitochondria use to divide?
Mitochondrial fission.
171
How are mitochondria inherited in humans?
Mitochondrial genes are inherited only from the mother.
172
What is the mtDNA bottleneck?
A process that increases cell-to-cell variability in mutant load during development.
173
What is the primary DNA repair mechanism employed in mitochondria?
Base excision repair.
174
Which organisms have completely lost mitochondrial DNA?
Cryptosporidium.
175
What are some diseases associated with mitochondrial dysfunction?
Kearns–Sayre syndrome, MELAS syndrome, Leber's hereditary optic neuropathy.
176
What is mitochondrial replacement therapy (MRT)?
A form of in vitro fertilization that uses donor mitochondria.
177
What role do mitochondria play in aging?
They are involved in oxidative stress and high mutation rates of mitochondrial DNA.
178
Fill in the blank: Mitochondrial dysfunction has been linked to diseases such as _______.
Parkinson's disease.
179
What is the impact of mitochondrial dysfunction on cardiac health in type 2 diabetics?
It leads to reduced cardiac efficiency and contractile dysfunction.
180
What is the relationship between mitochondrial function and ovarian aging?
Decreased mitochondrial function can lead to inflammation and premature ovarian failure.
181
What genetic changes can occur in mitochondria during aging?
Decreased enzymatic activity and accumulation of mutated mtDNA.
182
True or False: Mitochondria can undergo recombination.
True.
183
What is the main function of the proteins involved in mtDNA repair?
They are encoded by nuclear genes and translocated to the mitochondria.
184
What is the primary role of mitochondria in ovarian function?
Providing ATP necessary for the development from germinal vesicle to mature oocyte
185
What can decreased mitochondrial function lead to in ovarian health?
Inflammation, resulting in premature ovarian failure and accelerated ovarian aging
186
What are the three types of dysfunction associated with decreased mitochondrial function?
* Quantitative dysfunction (mtDNA copy number and deletions)
* Qualitative dysfunction (mutations and strand breaks)
* Oxidative damage (dysfunctional mitochondria due to ROS)
187
How do mitochondrial dysfunctions affect oocyte-cumulus crosstalk?
They perturb oocyte-cumulus crosstalk in the ovary
188
What genetic disorder is linked to mitochondrial dysfunction?
Fragile X
189
Who published the first observations of intracellular structures that likely represented mitochondria?
Albert von Kolliker in 1857
190
What term did Carl Benda coin for mitochondria in 1898?
Mitochondria
191
What was the significance of Friedrich Meves' observation in 1904?
First recorded observation of mitochondria in plants
192
What did Benjamin F. Kingsbury relate to mitochondria in 1912?
Cell respiration
193
Who discovered cytochromes and when?
David Keilin in 1925
194
What did Eugene Kennedy and Albert Lehninger discover about mitochondria in 1948?
Mitochondria are the site of oxidative phosphorylation in eukaryotes
195
When were the first high-resolution electron micrographs of mitochondria produced?
1952
196
What popular term was coined by Philip Siekevitz in 1957?
Powerhouse of the cell
197
In what year was it discovered that mitochondria contain ribosomes?
1967
198
What was completed in 1976 regarding mitochondrial DNA?
The genetic and physical map of yeast mitochondrial DNA
199
What discovery did researchers make in November 2024 regarding mitochondria?
Mitochondria divide into two distinct forms when cells are starved
