Cycle 6 BMP Workshop Flashcards
Define:
Endosymbiosis
Organelles coming together to live together within the cell
(Endo - “Within”, Syn - “Come together”, Biosis - “Living”)
Explain:
Specialization in the Cell
- Prokaryotic energy production is inefficient
- Specialization of certain organelles increases efficiency
- Specialized organelles allow for more efficient eukaryotic cells
True or False:
Organelles do not have their own electron transport chains
False. Organelles do have their own electron tranport chains and own ways of synthesizing proteins, similar to free floating prokaryotes
Do organelles divide separately from the cell?
Yes, organelles divide separately from the cell. Furthermore, organelles cannot be created by the cell once destroyed
True or False:
Organelles RNA is different from cellular DNA
True. Mitochondrial genome resembles that of heterotrophic bacteria while chloroplast genome resembles that of cyanobacteria
True or False:
The genome sizes of the modern mitochondria and chloroplast are larger than genome sizes of the ancestral organisms they originate from
False, the are significantly SMALLER than the genome sizes of the ancestral organisms they originate from
Where the genes from ancestral organisms of mitochondria and chloroplast go?
- Redundancy: Many genes found in aerobic bacteria and cyanobacteria are already found in the host cell
- Horizontal Gene Transfer (HGT): Overtime, genes of one genome can be relocated to another genome
What changes in HGT?
Gene location, not gene function
What is required for proteins encoded by nuclear genes that need to be transported to other organelles?
A signal peptide
Why is HGT performed?
- Integrative control: The nuclear genome is the main boss, giving it more genes means more control
- Safety: Nucleus is much safer compared to the highly reactive environments of the mitochondria and chloroplast
How are the environments of mitochondria and chloroplast reactive? (Give example)
The electron transport chain creates reactive oxygen series, which can cause DNA damage
How is Horizontal Gene Transfer detected?
DNA Hybridization
Desribe:
The process of DNA hybridization
- Make labelled probe; SS DNA probe that identifies gene of interest
- Allow for hybridization of labelled probe with SS nuclear and mitochondrial DNA
- If gene of interest is present in genome, labelled probe will bind to the SS DNA
How can we tell if the gene of interest is present in a DNA Hybridization?
There is a band present
What are proteins uniquely found in eukaryotes called?
Eukaryotic signature proteins (ESPs)
Where are ESPs also found? What do they do?
Found in a group of archaea called Asgard
* DNA packaging, nuclear proteins, protein synthesis, cell signalling, cytoskeleton
True or False:
Eukaryotes have a mixture of archeal and bacterial genes
True
What do the genes from Archaea and Bacteria do in a Eukaryote?
- Archaea: Genes for information processing and structure
- Bacteria: Genes for Metabolism
What characteristics do bacteria have as a prokaryote?
- Fast doubling time
- No nucleus, but circular chromosomal DNA
- Plasmids non chromosomal DNA
How are bacteria categorized? Explain the difference
Gram +ve/-ve; by using staining procedures:
* Gram +ve stains purple
* Gram -ve stains pink
Describe:
The wall and membrane structure of Gram +ve/-ve bacteria
- Gram +ve bacteria have a thick peptidoglycan wall with a cell membrane
- Gram -ve bacteria have a thinner peptidoglycan wall sandwiched between two membranes (cell membrane and outer membrane)
Describe:
Penicillin Mechanism of Action
- Mimics the substrate in the active site
What kind of inhibitor is penicillin?
Competitive inhibitor (irreversible; forms a covalent bond)
Describe:
Bacterial cell wall (Peptidoglycan)
- Peptide + Sugar (polysaccharide)
- Cross-linking of peptide chains catalyzed by transpeptidase
List:
Modes of Action by Antibiotics
- Attack cell wall formation (e.x. penicillin, vancomycin)
- Attack metabolic pathways (e.g. sulfonamides attack folate biosynthesis)
- Attack protein synthesis (e.x. kanamycin, tetracycline, lincomycin)
- Attack DNA replication/transcription (e.x. ciprofloxacin)
How do we determine the proper antibiotic to use?
Exploit the biochemical differences between bacterial vs. our cells
List:
Methods that differences between bacterial cells and our cells that antibiotics exploit
- Humans do not make folate, thus antibiotics can be used to attack folate synthesis in bacteria
- Antibiotics for attacking the ribosome for protein synthesis in bacteria
- Human chromosomes are not circular, thus antibiotic can attack the processes required for DNA replication and synthesis
Define:
DNA Gyrase
Circular genomes
True or False:
Antiobiotic use will harm the mitochondria
Not necessarily
* Mitochondria divide VERY slowly
* Long term use of antibiotics may affect mitochondrial function but not for very long
* Can switch antibiotics for long-term use
How is antibiotic resistance detected?
By seeing if there is a deadzone (no bacterial growth) when antibiotic is dripped onto bacteria in culture plate
How is antibiotic resistance developed?
- Random mutations
- DNA from already ressistant cells
True or False:
Mutations in DNA are rarely deleterious
False. Mutations from DNA are usually deleterious or neutral, rarely advantageous
If most mutations are deleterious or neutral, how do bacteria develop advantageous mutations?
Bacteria has a fast generation time (20 minutes), meaning there is a very high rate of mutations increasing the likelihood of advantageous mutations
* REMEMBER: Mutations are NOT a response to antibiotics, they are RANDOM
List:
Antibiotic Resistance Mechanisms (Intrinsic resistance)
- Increase expression of efflux pumps (pumps antibiotic out of bacteria)
- New protein with same function (antibiotic does not target that protein)
- Decrease expression of porin - influx (prevents antibiotic from getting in)
- Inactivation by modifying enzymes (targeting and breaking down antibiotics)
- Target site modification (antibiotic cannot inhibit protein)
Define:
Intrinsic resistance
The ability to resist the action of that antibiotic as a result of inherent structural or functional characteristics
What is the “last resort” antibiotic used?
Carbapenems (carb), a highly effective antibiotic
True or False:
Bacteria can become carbapenem resistant
True; a change in expression of one of three proin genes can prevent the antibiotic from entering
