DNA Organization Flashcards
What is a nucleosome and how are histones associated?
DNA is coiled coiled around bundles of 8/9 histone proteins. (beads on a string)
What is the difference between Euchromatin and Heterochromatin?
Euchromatin
- loosely bound to nucleosome and ACTIVE
Heterochromatin- areas of tightly packed nucleosomes where DNA is INACTIVE
- (condensed–>darker)
- (lots of DNA satellites_
What is another name for transposons and why?
“Jumping genes”
they are segments of DNA that can move to new location on same/different chromosome
What are the 2 components of a virus?
- nucleic acid (RNA or DNA)
- capisid (protein coat that encloses nucleic acid)
What assembles to form the capsid of a virus?
capsomeres
What is a bacteriophage?
virus that kills bacteria
What are the 2 cycles in virus replication?
Lytic cycle- virus penetrates and destroys DNA to reproduce
Lysogenic cycle- Virus penetrates and incorporates its DNA into the organisms DNA to reproduce
What 3 different viruses use the lytic cycle?
- DNA viruses
- RNA viruses
- Retroviruses
Why are retroviruses so crazy?
Give an example of a retrovirus.
DNA —> RNA using reverse transcriptase
eg. HIV
What organisms are Teichoic Acids found on and what is their function?
found only on gram-positive bacteria
- used as recognition + binding sites by bacteriophages that cause infections.
- Provide cell wall rigidity
What are prions and why can they be fatal?
not viruses or cells.
Misfolded versions of proteins in brain that can cause the normal to misfold too
What is the difference between homologous and analogous organisms.
Homologous- similar structure as a different species bc
they come from a common ancestor
Analgous- similar structure because of adaption to
environment
What is the definition of natural selection?
responsible for producing adaptions (superior inherited traits) to increase individual’s fitness
What is the definition of fitness in natural selection?
ability to survive, leave offspring
What are the 8 criteria statements of natural selection?
- populations possess an enormous reproductive
potential - population size remain stable
- Resources are limited
- individuals compete for survival
- there is variation among individuals in a population
- much variation is heritable
- only the most fit individuals survive
- evolution occurs as favorable traits accumulate in the
population
What is genetic drift?
random increase/decrease of allele by chance
small population —> larger effect
What is the Hardy-Weinberg equilibrium equation?
p^2 + 2pq + q^2 = 1
What is the criteria for the Hardy-Weinberg equilibrium?
- No mutations
- No natural selection
- No gene flow (isolated population)
- No genetic drift (Large populations)
- No net migration
- Random mating
What is the definition of polyploidy?
possession of more than normal two sets of chromosomes
What is the definition of hybridization? (animal hybrid)
two different forms of species (closely related) mate and produce along a geographic boundary called hybrid zone.
What is the definition of adaptive radiation?
rapid evolution of many species from a single ancestor
What is the difference between Directional selection, Stabilizing selection, Disruptive selection, Sexual selection and Artificial selection?
Directional selection- favors extreme traits (eg. giraffes neck)
Stabilizing selection- favors intermediate trait (average height in human is in the middle)
Disruptive selection- occurs when environment favors extreme or unusual traits while selecting against common traits.
Sexual selection- females favor superior traits in males (more beautiful peacocks get the bitches)
What are the 5 Prezygotic isolation mechanisms and what are the 3 Postzygotic isolation mechanisms?
Prezygotic
- Habitat isolation
- Temporal isolation (only mate during specific season)
- Behavioral isolation (incorrect ritual to pull bitches)
- Mechanical isolation (male/female genitalia incompatible)
- Gametic isolation (gametes are incompatible)
Postzygotic
- zygote inviability (fail to develop properly–>dies)
- Hybrid sterility (hybrids become functional adults but cant reproduce)
- Hybrid breakdown (hybrid has offsprings that have reduced viability/fertility
What is the difference between Divergent evolution, Convergent evolution, Parallel evolution and Coevolution?
Divergent evolution- 2 or more species w/ common ancestor becomes increasingly different over time (result of speciation)
Convergent evolution- 2 unrelated species that share similar traits by environment (analogous traits)
Parallel evolution- 2 related species made similar evolutionary changes after divergence from common ancestor
Coevolution- evolution of a species in response to new adaptions that appear in another species (predator/prey)
How old is the Universe?
12-15 billion yrs
How old is the Solar System?
4.6 billion yrs
How old is the Earth?
4.5 billion yrs
How long ago did the first life on Earth appear?
3.6 billion yrs
How long ago did the first photosynthetic bacteria appear?
2.3 billion yrs
How long ago did the first Eukaryote appear?
1.5 billion yrs
What is the hierarchy of the classification of organism in order from highest to lowest?
hint (Dumb Kings Play Chess On Fine Green Sand)
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What is the difference in the biological diversity of prokaryotes and eukaryotes?
Prokaryotic cells:
-single chromosome is short, circular DNA with/without histone;
-may or may not contain Plasmids
-No nucleus
-No organelles
-flagella consist of chains of protein flagellin instead of
“9+2” microtubules
Eukaryote:
- chromosomes contain long, linear DNA with histone
- Nucleus
- organelles
- 9+2 microtubule array flagella and cilia
What is the difference between, Autotrophs, Heterotrophs, and Saprobes (saprophytes)?
Autotrophs- use light to manufacture their own organic materials
Heterotrophs- obtain energy by consuming organic substances produced by autotrophs
Saprobes- obtain energy from dead, decaying matter (Decomposers)
What is the difference between Obligate aerobes, Obligate anaerobes and Facultative anaerobes?
Obligate aerobes- need O2 (top of vial)
Obligate anaerobes- Lives without O2 (bottom of vial)
Facultative anaerobes- grows in presence of O2, but can live without it. (near the top) too much O2 is toxic
