Ribosome number for archea and eukaryotes
80s
Subunits of archea and eukaryotic ribosomes
40s and 60s
Ribosome number for bacteria
70s
Subunits for bacteria ribosomes
30 and 50s
What is the ribosome number based on
Sedimentation
Shape of DNA in mitochondria and chloroplasts
Circular
What do mitochondria come from
Prokaryotes
What causes genes to be lost in mitochondria
Mitochondria are recycled and their genes spill into the cytoplasm and go into the nucleus
Why can mitochondria no longer survive outside the cell
Genes lost to nuclear DNA
Endosymbiont theory
Bacteria (mitochondria) wound up in archea and fed off its nutrients. Energy it produced spilled out into the cell. Both benefitted
What was caused by chloroplasts living inside a host for the first time
Early algae
How do mitochondria lead the way to multicellularity
Mitochondria with electron transport introduced into cells that only went through fermentation
How do we know fermentation is still in our genes
Skeletal muscles still use it
How are codons different in mitochondria
Different start and stop codons
What is the start codon in mitochondria
AUU (methaiamine, but encodes ile during elongation)
Why do chloroplasts have 2 membranes
They lost their cell wall
What cells have the most mitochondria/chloroplasts
The cells that need the most energy
How mant chromosomes do mitochondria have
One
What happens to mitochondria if the cell doesnt need them anymore
They fuse together
What does rupture of mitochondria cause
Apoptosis
Gene gun
Delivers DNA molecules into certain organelles through a gold bead that has flanking regions that match up to the part of the cell where you want to insert it
How is DNA inserted by a gene gun integrated into the genome
Homologous recombination
mtDNA mutations
Occur slowly over time and are more common in somatic cells
How is maternal inheritence tracked
Mitochondria
How is paternal lineage tracked
Y chromosome (can only be tracked in males)
Where is mitochondria found in a sperm
Neck
Why are the mitochondria stacked in the sperm
To fit a lot of them to power the flagellum
Why don’t the paternal mitochondria get transferred to the offspring
Only the head of the sperm enters the egg
What causes white and green leaves on a plant
Abnormal chloroplasts
Heteroplasmic
2 types of mitochondria. Some mutant and some normal
Homoplasmic
One type of mitochondria
What does a pedigree look like with mitochondrial diseases
All females offspring of females will have the disease
Oxidative phosphorelation
Production of ATP and free radicals (accelerates mutation rates over time)
How can a mother with mitochondrial disease have a child without it
Can’t without genetic engineering. Put mothers nucleus from cell with diseased mitochondria into a cell without diseased mitochondria
What types of cells do cancers originate in
Somatic cells
Characteristics of cancer cells
- Telomerase allows them to live indefinitely
- Cancer cells clear checkpoints
- Genes that induce apaoptosis must be damages
- Loses contact
How is cancer inherited
If you are heterozygous for gene that controls cell cycle and the other normal one becomes mutated
Why is oxygen not required for cancer cell growth
They only undergo fermentation
How does cancer spread
Cancer cells produce substances to cause blood vessels to enter tumor
Why is cancer generally a disease of old age
Mutations accumulate
Signals that signal cells to divide
- Extracellular
- Cell bound signals
- Autocrine
Extracellular signals
Hormones (cell receptors get turned on even when the hormone isnt there to proliferate)
Cell bound signals
Comes from cell to cell attachment
Autocrine signals
Cells can self stimulate until it contacts other cells
CDK
Cyclin dependent kinase
-Adds phosphates to other proteins needed for cell cycle. Activated by cyclin
What happens when cyclin is always at the CDK
CDK is always active. Cells keep growing
Genetic predisposition to cancer
Heterozygous. Only need one gene to mutate rather then 2
What is the first step in cancer development
Errors in repair mechanisms
Signaling
Growth factors
Receptors
Signal transducers
Transcription factors
Growth factors
Hormones (bind to cell and stimulate it to grow)
Receptors
Recieve signals
Signal tranducers
Single signal activates many pathways
Transcription factors
Activate expression of genes needed for cell division (or preventing cell division)
Type of transcription factor
Kinases
What do checkpoints prevent
Point mutations
Translocation
Gene amplification
Oncogenes
Promote cancer when mutated
- “gain of function”
Tumor suppressors
Slow down the cell cycle
-“loss of function”
Types of oncogenes
Ras and Her2
How does radiation not affect the normal cells it passes through
Low doses are shot from all different angles and meet in the middle
Population genetics
Distribution of alleles
How many alleles in a population
Double the amount of people (ex: 20 people, 40 alleles)
Hardy weinberg formula
P^2+2pq+Q^2=1
What does p stand for
Frequency of A
What does q stand for
Frequency of a
What does the hardy weinburg formula state
Allele frequencies should eventually reach equilibrium
Fixation
When one allele is removed from a population
What populations is genetic drift more common in
Small populations
If there are 10 people in a population, when will most alleles be lost by
Within 20 generations
Bottleneck
Allele frequency shifts due to a large portion of the population dying off and having to repopulate
Founder effect
People mate with only other people in their area (allele loss)
Mitochondrial genome
- Genes encode tRNA, rRNA, proteins for oxidative phosphorelation
- No introns
Function of chloroplasts
Captures solar energy and stores it in chemical bonds
Chloroplast genome
- Has introns
- Have more genes than mitochondria
- Can be branched, circular or linear
Transplasmatonic plant
Cells with gene inserted by gene gun cultured into a plant
Cytochrome oxidase c
Functions in mitochondrial electron transport
- 7 subunits. 3 encoded by mitochondrial genome. 4 by nuclear genes
What do mtDNA mutations cause
Slow cell growth (small cell colonies and weak tissues)
What do cpDNA mutations cause
Changes in leaf color
What is a plant called with cpDNA mutations
Variegated
How are mitochondrial diseases passed
From mother to children
What cells do mutations occur in that cause cancer
Somatic
3 ways cancer cells evade normal growth
Produce cell division signals
Lose contact
Avoid apoptosis
How do cancer cells live indefinitely
Expression of telomerase (maintains length of chromosome ends)
Gene pool
Total of all alleles carried in members of a population
Assumptions of hardy weinburg
- Population has infinite number of individuals
- Individuals mate at random
- No new mutations appear
- No migration
- Genotypes have no effect on the ability to survive and transmit alleles to the next generation
What is hardy weinburg useful for
Estimating population changes through a few generations, not long term
Monte Carlo simulations
Use a computer program to model possible outcomes of randomly chosen matings over a designated number of generations