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bio test 6
| Question | Answer |
|---|---|
| all cells in the body have how many chromosomes except for reproductive cells | 46 chromosomes |
| if all cells have 46 chromosomes then... | all cells have the same genes |
| gene expression is regulated by | 1. turning genes on or off with transcription 2. varying rate of transcription or translation |
| genes are turned on or off depending on | 1. developmental stage 2. type of tissue 3. stage of physiological cycle 4. external environmental cues |
| RNA polymerase in gene expression | binds to promoter starting the process of transcription |
| promoter in gene expression | sequence of DNA that promotes transcription |
| transcription factors in gene expression | regulate attachment of RNA polymerase to the promoter (activator/repressor proteins) |
| activator proteins | recruit RNA polymerase to the promoter; initiate transcription |
| repressor proteins | block RNA polymerase from the promoter; prevents transcription |
| describe the importance of the human SRY gene | regulatory gene that codes for an activator protein which turns on other genes needed to develop testes |
| gene families | groups of similar proteins; similar AA sequence's and similar heme group attachment |
| protein families | genes are on 3 chromosomes and all genes on one chromosome have the same AA length |
| pseudogens | damaged genes without transcription; cant be turned on or expressed |
| where do genes/ gene families come from | gene duplication |
| definition of gene duplication | extra copy of a gene that can mutate and acquire a new function |
| causes of gene duplication | 1. unequal crossing over during myosis 2. duplication of entire chromosome 3. mutation of a new start codon 4. viral genes |
| how do proteins change | mutations |
| basic structure of fetal blood vessels in placenta and how it contributes to their lack of O2 | vessels extend into a pool of mothers blood which is both oxygenated and deoxygenated so it has low PO2 |
| If the fetus has low PO2 | it experiences high altitude conditions in the womb |
| how does the fetus get sufficient O2 | reduction of 2,3-BPG--> increases HbO2 affinity |
| embryonic vs. fetal Hb | embryonic Hb has a higher O2 affinity than HbF |
| what is the molecular mechanism the increases the O2 affinity of HbF | 2,3 BPG does not bind with HbF creating a gap between subunits that allows O2 to easily enter |
| recall the succession of Hb variants during human development | embryonic: ends about 10 weeks HbF: ends about 6 months HbA: after about 6months |
| how could the succession of Hb variants be used to possibly treat sickle cell anemia | artificially express the HBG gene and suppress the HBB gene which could result in a higher Hb affinity that is not as effective at low altitudes but will lack the sickle cell trait |
| what problem do high altitude geese face at the beach and how does it affect their fitness | high altitude Hb has reduced efficiency at low altitudes because O2 does not release easily which is a problem for sustained flight and will reduce their fitness |
| two possible theories for a solution to geese wintering at the beach | 1. increase the level of 2,3-BPG in RBC--> lowers O2 affinity 2. express a gene for Hb variant with lower HbO2 affinity |
| where does the Andean goose live | Andes mountains +3000m |
| how does the Hb of Andean and bar-headed geese compare | both high altitude Hb, bar headed: proline is replaced by alanine, Andean: leucine is replaced by serine, both mutations cause a gap between subunits (relaxed state)--> high affinity, have the same affect on the quaternary structure |
| why is meat red | muscles contain myoglobin |
| what is the function of myoglobin | O2 storage in endurance muscles |
| does myoglobin have a sigmoidal curve | no, the sigmoidal shape comes from cooperative binding and because myoglobin only has one heme this is not possible and has a regular curve |
| what color is oxy-myglobin | bright red |
| what color is deoxy- myglobin | dark red |
| compare the dissocation curve between myglobin and hemoglobin | myglobin is shifted left relative to Hb and has a much higher affinity |
| if H2 binds to myglobin instead of O2 the meats color will be | brown |
| If CO or NO binds to myglobin instead of O2 the meats color will be | pink |
| why is meat color not an indication of the freshness of the meat | They can be packaged with gas to give it a fresh color or a O2 permeable film |
| node | point of divergence |
| clade | all of the decedent's of a common ancestor |
| convergent evolution | organisms share the same phenotype or trait but are unrelated in every other way |
| what are two possible explanations of convergent evolution | 1. trait inherited from a common ancestor 2. trait developed independently from the same selection pressures |
| biological species concept | group of organisms that have the potential to breed with each other and produce live and fertile offspring |
| define a species according to biological species concept | dogs and different breeds |
| speciation | one population evolves into two different populations |
| steps of speciation | 1. a population is divided into two isolated populations 2. genetic differences build up between populations until they are two great the two populations can no longer breed |
| chemical compounds strongly implicated in climate change | carbon dioxide, methane, nitrous oxide, chlorofluorocarbons, water vapor |
| describe how warming is from greenhouse gas and not increased energy from the sun | in the past 20 years irradiance has decreased while temperatures continue to increase |
| How does climate change correlate to events during carboniferous | burning of fossil fuels or during this time lignin from trees resulted in more CO2 in the environment |
| describe paramo ecosystem | above 12,500ft, temperature fluctuations, collects water, 5000 species home |
| likely response of the Andean humming bird due to climate change | migrating further up the mountain towards colder temperature's |
Created by:
mrmhky
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