Mitochondria Flashcards
What types of lifeforms combined via endosymbiosis to eventually give rise to mitochondria?
free-living aerobic heterotrophic prokaryotic bacteria was engulfed by an anaerobic archaea
Mitochondria are often ___ like organelles located in the cells of almost all _______
rod, eukaryotes
What is one eukaryote that does not have mitochondria?
monocercomonoides
Why do people believe mitochondria originated from bacteria?
The little amount of DNA they contains is most likely bacterial DNA
What does sequencing of numerous mitochondrial DNA confirm?
- All mitochondria originated from the integration of a eubacterial ancestor into a host cell related to asgard archaea
- The transition to permanent organelles entailed a massive number of evolutionary changes
- The above changes occurred incrementally as the endosymbiont and the host became integrated
What is symbiosis?
A typically advantageous interaction between two different organisms living in close physical association
How is the archaea and bacteria merging symbiotic?
The archaea was anaerobe. By combining with aerobic bacteria, it can do respiration
Bacteria gained protection by living inside archaea
Describe how the DNA of the bacteria and archaea merged gradually over time
Each prokaryote has its own set of DNA (a genome). The bacteria’s genome remains
separate (curved blue line) from the archaea’s genome (curved purple line). The bacteria
continued to replicate within the host cell. Over time, during errors of replication or
perhaps when the bacteria lyses and loses its membrane separation from the host, genetic
material becomes separated and merges with the host cell genome. Eventually, the host
genome becomes a mixture of both genomes, and it ultimately becomes enclosed in an
endomembrane, a membrane within the cell that creates a separate compartment. This
compartment eventually evolves into a nucleus.
What are the 4 benefits of the bacteria merging into the archaea?
- Extra energy allowed archaea to focus on other things, like membrane bound organelles and a nuclear envelope
- Specialized functionality for each organelle
- Mitochondrial division occurred, merging some of it’s DNA into the eukaryotic cell
- Evolution of the nucleus
What are nuclear pores? What do they do?
They are tiny pores in the nuclear envelope. They selectively permit certain macromolecules to enter and leave the nucleus, including RNA
Why are eukaryotic cells able to more intricately regulate protein production?
The separation of the DNA from the protein synthesis
How to prokaryotic cells multiply?
Binary fission process, since they don’t have a nucleus. It’s fast and hard to control, which is problematic when a cell forms part of a larger organism
What happens when cell replication coordination fails in a multicellular organism?
cancer
Cellular respiration gives around __ ATP per glucose molecule while fermentation gives _ ATP
30, 2
What is an autotroph and heterotroph?
Autotroph: Organism that makes complex org compounds using carbon from substances such as CO2. generally uses light or inorganic chemical reactions
Heterotroph: Organism that cannot produce its own food and consumes autotrophs
What’s the 2nd law of thermodynamics?
In a closed system of reactions, entropy increases. Energy is always lost as heat in a reaction
What prevents the universe to disintegrate?
Influx of energy from the sun.
What is energy from the sun stored as?
Organic molecules such as carbs and fats. Also converted into ATP
What is ATP?
The energy currency the powers any non-spontaneous reaction
What produces ATP?
Mitochondria
What percentage of ATP do mitochondria supply?
~90%
What is the process of turning oxygen and food into ATP called?
Cellular respiration
~1890, who showed strings of granules in cells and called them bioblasts?
Richard Altmann
When did Carl Benda coin the term mitochondria?
1898
When and who linked mitochondria to cellular respiration?
1913, Otto Heinrich Warburg. From guinea-pig liver
When and who discovered cytocrhomes?
1925 David Keilin
Around what time did scientists discover that mitochondria could produce ATP and that one oxygen atom produces 2 ATP molecules
1930s and 40s
Describe the mitochondria’s structure according to 1952 information
Surrounded by outer membrane
Inner membrane folds inwards to form cristae, which are surrounded by the fluid matrix
What are 2 byproducts from cellular respiration?
Water and CO2
When and who proposed the chemiosmotic theory for ATP production
1960, Peter Mitchell
What is Chemiosmosis
movement of ions (charged particles) across a semipermeable membrane, down their electrochemical gradient
What is ATP synthase?
Enzymes located on the inner membrane of the mitochondria that create ATP molecules
How does ATP synthase make ATP?
Via the movement of hydrogen ions across the membrane during cellular respiration. H+ ions are moved from a region of high concentration (space between membranes) to low concentration (matrix)
Describe the electron transport chain and how ATP is generated
Refer to slide 5-32
The citric acid cycle help pump H+ into the intermembrane space, which is then used to produce ATP
What kinds of cells can require lots of ATP and have about 1000-2000 mitochondria per cell
Muscle and Liver tissue cells
Describe mitosomes, aerobic mitochondria, anaerobic mitochondria, and hydrogenosomes
mitosomes: Do not generate ATP
aerobic mitochondria: Uses O2 to make energy
anaerobic mitochondria: Do not produce H2
hydrogenosomes: Do not possess electron transport chain
What functions do mitochondria serve besides energy production
Heat production (protons re enter matrix without making ATP. This generates heat)
Storage of calcium ions
Regulation of cellular proliferation
Involved in Apoptosis
What are mitochondrial diseases?
Inherited disorders caused by dysfunctional mitochondrial
Where do mitochondrial diseases hit the hardest. Why?
Muscles, brain, digestive system, and kidneys as they all use lots of energy
What are symptoms of mitochondrial diseases?
- poor growth
- loss of muscle coordination, muscle weakness
- visual and hearing problems
- learning disabilities
- heart, liver, kidney diseases
- gastrointestinal and respiratory disorders
- neurological problems
- autonomic dysfunction and dementia
What are examples of mitochondrial diseases?
- diabetes
- Huntington’s disease
- cancer
- Alzheimer’s disease, Parkinson’s disease
- bipolar disorder, schizophrenia, anxiety disorders
- aging and senescence
- cardiovascular disease, chronic fatigue syndrome
Describe Parkinson’s disease
A neurological disorder caused by diminished energy production, which affects neuron function. In addition, calcium ion homeostasis is also disrupted
How is mitochondria linked to the aging process?
Mitochondrial dysfunction and disruption of the balance between the generation of new and removal of damaged mitochondria is linked to the aging process.
