VERY IMPORTANT Flashcards
What is the difference between Allopatric and Sympatric speciation?
Allopatric- population is divided by geographic barrier—> interbreeding between 2 resulting populations is prevented—> gene frequencies in 2 population can diverge due to natural selection, mutation, genetic drift. If gene pool is sufficiently diverge—> will not interbreed when barrier is removed—> new species formed.
Sympatric- formation of new species in absence of geographic barrier; (balanced polymorphism, polyploidy, and hybridization)
How did the earth’s atmosphere form?
through volcanoes (CH4, NH3, CO, CO2, H2, N2, H2O, S, HCl, HCN, and little/no O2)
What was Oparin and Haldane’s hypothesis of the origin of life?
organic soup theory, if there was O2 (very reactive), no organic molecules would have formed.
***Operin’s hypothesis was that origin earth environment was reducing (providing chemical requirements to produce complex molecules from simple building blocks. In an oxidizing environment you’d break complex molecules apart)
What did Stanley Miller discover while tested Oparin’s theory?
Miller and Urey used ammonia, methane, water and hydrogen sealed + simulated lighting—> saw several organic molecules, AA’s, starting material, but no NAs (nucleic acids).
What theory explains how eukaryotes formed and what evidence proves this theory?
endosymbiotic theory
Thylakoid membranes of chloroplasts resemble photosynthetic membranes of cyanobacteria
What is gel electrophoresis primarily used for and what else is can be used in gel electrophoresis?
Used for distributing DNA by size to identify location of specific sequence of DNA.
you can also do gel electrophoresis on PROTEINS by adding SDS to denature, linearize, and add negative charge
What restrictive enzymes are used by bacteria to protect against viral DNA and how do these enzymes do this?
EcoRI and BamHI
done by methylation to very tightly condense chromatin protecting is from viral DNA
What organism is the Lac operon found and what is the purpose and mechanisms of it?
E. coli
controls breakdown of lactose; regulatory gene produces active repressor (bind operator) and block RNA pol.
When lactose is available, lactose binds repressor and inactivates it—> RNA pol can now transcribe
Lactose induces the operon. The enzymes that the operon produces are said to be inducible enzymes.
Note: consists of three lac genes (Z, Y, A) which code for B-galactosidase, lactose permease, and thiogalactoside transacetylase.
Also know that low glucose means high cAMP levels—> cAMP binds to CAP binding site of promoter—> RNA pol more efficiently transcribes—> high lactose levels
What organism is the trp operon found and what is their function?
E. coli
Produces enzyme for tryptophan synthesis; regulatory genes produce an inactive repressor—> RNA pol produces enzymes.
When tryptophan is available, no longer need to synthesize it internally: it binds to inactive repressor and activates repressor—> able binds operator and block RNA pol. Tryptophan is corepressor
What are the differences between the 3 genetic variations of bacteria?
(Conjugation, Transduction, Transformation)
- Conjugation- donor has the F plasmid, which produce a
bridge (pilus) and connect to recipients;
send chromosome/plasmid to recipient and recombinant can occur; F plasmid allowing pilus to occur; once recipient receives, it is now F+ and can donate as well. R plasmids provide bacteria with antibiotic resistance. Pili are also used for cell adhesion
- Transduction- DNA is introduced into genome by a virus.
When a virus is assembled during lytic cycle, some bacterial DNA is incorporated in place of viral DNA. When virus infects another host, the bacterial DNA part that it delivers can recombine with the resident DNA.
- Transformation- bacteria absorb DNA from surrounds
and incorporate into genome
What organism contains Teichoic Acids and what is it’s functions?
Gram-positive bacteria only!!! (cell walls)
used as recognition + binding sites by bacterial viruses that cause infxns; also provide cell wall rigidity.
What does a Nucleosome look like and why?
“beads on a string”
DNA is coiled around bundles of 8/9 histone proteins
What is the start codon in bacteria opposed to humans?
Bacteria: n-formylmethionine
Humans: methionine
What is the difference between a silent mutation, nonsense mutation and missense mutation?
Silent mutation- new codon still codes for the same amino acid
***Nonsense mutation- new codon codes for a stop codon
Missense mutation- new codon codes for new amino acid—————————–> minor or fatal results as in sickle cell (val(new) for glu(old))
Which syndromes cause mental retardation and which one doesn’t?
Mental retardation- Down syndrome, Kline, and Cri Du Chat (deletion on chromosome 5)
Does NOT cause mental retardation—> Turner’s syndrome
