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207 Cards in this Set
- Front
- Back
What can only be viewd by electron microscopy?
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Viruses
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What is true of enzymes?
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They are a specific biological catalyst, were originally known as ferments, and may function separately from cells
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The limit of resolution can best be defined by?
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The distance that two objects must be apart in order to be distinguished as separate objects
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What microscopic technique is least likely to be used to view alive, motile protozoa?
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electron microscopy
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What is true of a nanometer?
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a nanometer is also called a millimicron
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what organelle is round and derives its name from the latin work of kernel?
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nucleus
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What is closest to a micrometer in size?
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a typical bacteria cell
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gregor mendel was most influential in what field of biology
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genetics
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hereditary factors is an old name for?
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genes
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what is not a tenet of the cell theory?
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all cells have a membrane bound nucleus
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cell biology emerged from what field of biology?
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genetics, biochemistry, and cytology
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what type of microscopy has the greatest resolving power?
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electron
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the ___ model of DNA structure was proposed by ___
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double helix, watson and crick
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what biological polymer is mismatched with its monomer?
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cellulose - amino acid
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the heirarchical nature of cellular structure is best illustrated in what list of substances?
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nucleotide, DNA, chromosome, nucleus, cell
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what is not a structural polysaccharide?
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glycogen
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what is the best explanation for the lack of activity of the synthesized enzyme?
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the synthesized enzyme was not folded correctly because molecular chaperones were not present
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what is not true of phosopholipids?
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sphingolipids are the predominant phosopholipid in membranes
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the primary structure of a protein
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all of the above
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cellulose belongs to which group of macromolecules?
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carbohydrates
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what has the greatest number of glycosidic bonds?
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amylose
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hydrogen bonding is most important in stabilizing the ___ structure of many proteins?
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secondary
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what is not true of amino acids?
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all amino acids exist in two steroisomeric forms
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what is not a major functional class of proteins?
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trifunctional
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frederick sanger recieved a nobel prize for his work on the structure of what?
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insulin
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whatis not characteristic of DNA?
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contains ribose
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what is not a base used in DNA replication?
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uracil
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what is true of purines?
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purines have a double ringed structure
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what describes the number of carbon atoms in glucose?
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hexose
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what is a disaccharide?
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lactose
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what is not one of the six classes of lipds?
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pectins
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what is true of fatty acids?
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saturated fatty acids have no double bonds between carbons
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what is true of glycolipids?
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glycolipids are usually found on the exterior surface of the plasma membrane
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which of the following are components of chargaffs rules of bases?
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all of the above
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an example of a purine is
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guanine
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DNA is different from RNA in that
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RNA contains an additional oxygen atom on the ribose sugar
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DNA has an adenine contant of 25%. what is the %G+C in this DNA?
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50%
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Which of the following shoes Chargaff's equivalence?
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synthetic DNA (one strand all A, the other all T)
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what regarding the watson-crick model of DNA is not accurate?
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it is a left-handed helix
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what is not a characteristic of prokaryotic genomes?
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presence of introns
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you and your neighbor have how much difference in DNA sequence?
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0.1%
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The phase of cell cycle associated with replication of DNA is
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interphase
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fractionation of cell organlles shows that
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each organelle is responsible for specific cell activities, there is some degree of autonomy in cells, and we can study each organelle individually outside the cell
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what bonding statement is incorrect?
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peptide bonds hold nucleic acids together
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denaturation of proteins results in
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breakdown of the teriary structure
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what statement about protein is correct?
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peptide bonds are resonsible for teh primary structure, H-bonds for the secondary structure, ionic bonds for the tertiary structure, and sulfhydryl bonds for tertiary structure
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all of the following are present in DNA except
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sulfur
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what kind of chemical bonds are found between paried bases of the DNA double helix?
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hydrogen
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all of the following statements apply to the watson and crick model of DNA except:
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the two strands of the helix are held together by covalent bonds
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what statement about enzymes is incorrect?
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enzymes can make a thermodynamically impossible reaction possible
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what is Km in enzyme mediated reaction?
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a measure of enzyme-substrate affinity, the lower the Km the higher the affinity and the concentration of substrate needed for reaching 1/2 Vmax
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Mitochondria is absent in what cells?
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E.coli
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What statement about cell culture is correct?
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plant cell culture medium is the simplest
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what organism is not most commonly used in molecular biology research?
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earthworm
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in evolution of life on earth what is the correct order of emergence?
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bacteria, protista, plant, animal
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enzymes work in the presence of vitamins and minerals because
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coenzymes are vitamins which enhance enzyme-mediated reactions, and vitamins and minerals help the enzyme to become active
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what technique is used to fractionate cellular organelles?
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gradient centrugutins
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which of the following is found in bacterial cells?
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ribosome
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One of the most important parts of meiosis?
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recombinations
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what is the nature of DNA replication?
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semi-conservative
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how was the semi-conservative nature of DNA replication discovered?
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N15 labelling and centrifuging (3 bands)
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what bases are needed for replication?
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ATP, GTP, CTP, and TTP
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why does replication need triphosphates?
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the energy they release when broken down allows the reaction to proceed (3.5 vs. 7.5 bond energy)
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Where does replication start?
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at the replication orgin which is ~1000 nucleotides long all A-T
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Eukaryotic vs. Prokaryotic orgins of replication
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prokaryotes have only one, but eukaryotes may have up to 10,000
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why is the replication origin all A-T?
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A-T bonds have only 2 hydrogen bonds as opposed to G-C's 3. so its easier to break there
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Where does DNA synthesis occur?
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at the replication fork
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What do you need for DNA to start synthesizing?
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a primer (a short legnth RNA)
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primer + helicase =?
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primosome
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DNA polymerase works in what direction?
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5' to 3'
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What quality is the replication fork?
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assymetric because of leading and lagging strand
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How accurate is DNA polymerase?
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its only makes 1 in 10^7 mistakes
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DNA polymerase has 2 sites for what functions?
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DNA synthesis and proof-reading
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proofreading is in what direction?
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3' to 5'
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what is nuclease's function?
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to remove the primers off the lagging strands so they cna be joined by ligase
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what mutation does sicle cell anemia involve?
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a single nucleotide change from A to T
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Kornberg could make ___, but not ___
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synthetic and biologically active DNA and viruses, but not DNA polymerase
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To finish replication these must be replicated
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telomeres
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What makes the end parts of DNA?
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telomerase (an RNA polymerase)
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Telomerase is what type of enzyme?
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a synthesizing enzyme, it doesnt break anything
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How many cell divisions in a cell life?
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80-100
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DNA polymerase is what quality?
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self-replicating (because it makes the gene for itself)
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Damage to DNA can happen by what?
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chemical and physical agents (ex. electromagnetic radiation)
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There is a low chance of getting cancer at a young age because?
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the immune system is better at recognizing foreign cells and DNA polymerase is better
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DNA repair involes 3 steps
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excision, resynthesis, and ligation
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transposable elements are also called
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jumping genes
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A large fraction of the human genome is made of?
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2 families of transposable elements
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Transposable elements can be identified by?
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the teriminal inverted repeats next to flanking direct repeats
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Jumping genes are responsible for?
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verigated kernels and chromosome rearragements (like inversion)
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transposable elements need?
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DNA polymerase
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Two types of transpositions?
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cut and paste and copy and paste
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Bacterial transpsans move by?
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cut and paste
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Retrotransposons are unique to?
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eukaryotes
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retrotransposons function to?
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make RNA copies of transposable elements using RNA polymerase and reverse transcriptase
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Two enzymes that help to unwind?
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helicase and gyrase
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How viruses vary?
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they can be DNA or RNA, and there are plant, bacterial, and animal viruses
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Viruses that attack bacteria are called?
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bacteriophages
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Viruses only attack their specific cell because of?
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their protein coat
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What is the Molecular Conspiracy?
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the viruses genetic material make an infected cell replicate the virus DNA (~50 viruses) until the cell explodes
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Two processes going on inside a viruses host cell?
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Replication making more virus DNA and transciption--> translation that makes protein coat
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Viruses can mutate frequenty because
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they do not have repair machanisms
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How many genes in E.coli, yeast, and humans?
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4000, 15000, and 30000
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What percentage of genes are continually functioning?
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10%
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Transciption needs?
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RNA polymerase (does not need a primer)
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4 types of RNA?
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mRNA (gene copy), tRNA (for transfer), rRNA (plus a protein gives a robozome), and snRNA (is a ribozyme)
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What is the difference between ribose and deoxyribose?
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ribose has an OH where deoxyribose has an H
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What is the difference between uracil and thymine?
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Uracil has an H where thymine has a CH3
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What at the beginning and end of a gene in DNA?
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a promoter and a terminator
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What initiates transciption?
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the sigma factor binding to the promotor
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In which direction does transciption move?
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5' to 3'
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About how long does it take to transcibe one gene?
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50 seconds
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What must RNA have to make it more stable?
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a cap and a tail
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What is the max life span of RNA?
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up to 1/2 hour
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DIfference between eukaryotic mRNA and prokaryotic?
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Prokaryotic can transcibe several genes at once
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What does the cap and tail of mRNA look like?
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The cap is 3 phosphates, a G, and CH3. A tail is 5 As
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What process is used to cut out introns?
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splicing
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What is a splicesome?
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a combination of snRNA and proteins that make a complex called a SnRNP (involved in splicing)
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What is the age range of mRNA?
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3 minutes to 10 hours (average is 30 minutes)
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Where does transciption and translation occur?
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Transciption is inside the nuclues, translation is outisde on a ribosome (in eukaryotes)
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What is making the tail of mRNA called?
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polyadenylation
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What do types 1, 2, and 3 RNA polymerase make?
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1-rRNA, 2-mRNA, 3-tRNA
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Who cracked the genetic code of translation?
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Nirenburg
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Which two amino acids are only coded for by one codom]n?
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Met and Trp
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There are 64 codon combinations, but only 20 amino acids which displays the quality of?
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redundancy
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The sigma factors purpose is to allow
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the RNA polymerase to stick to the DNA
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Some genes can be spliced in different ways to make different mRNAs, like...
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alpha-tropomyosin
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What is the initiation codon and the terminator codons?
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initiation-AUG (Met)
terminator-UAA, UAG, UGA |
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The fact that some amino acids are coded for by several codons displays what quality?
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degeneracy
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How many tRNA's are there?
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30 in prokaryotes, 50 in eukaryotes. tRNAs are iso-accepting
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What is the reading frame set by?
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the initiator codon
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In order to attach to a ribosome mRNA needs?
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a Shine-Delgarno box
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tRNA consists of?
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3' end, T loop, D loop, and the anticodon loop
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Where are ribosomes assembled?
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within the nucleolus of the nucleus
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How big are the large and small subunits in eukaryotic vs. prokaryotic DNA?
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eukaryotic-40s and 60s
prokaryotic-30s and 50s |
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What does the s stand for in mesauring ribosome subunits?
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svedberg unit (involves the density in a centrifuge)
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What are ribosomes made of?
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rRNA and proteins
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How many rRNAs and proteins in the large and small subunits of ribosomes in eukaryotes?
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large-3 rRNA, 49 proteins
small-1 rRNA, 33 proteins |
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How do the ribosome parts fit together?
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no chemical bonds, just sit together
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What does the initiation of translation in bacterial cells require?
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several initiation factors and GTP
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What are the 3 steps of translation?
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initiation, elongation, termination
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What are the three sites on the ribosome?
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A, P, and E site
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What does the termination codon do?
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It attracts release factors that disassemble the ribosome
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What are the two types of ribosomes?
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Free ribosome (if protein is for inside of the cell) and membrane-bound ribosome (if protein will be used in the membrane or ouside of the cell)
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How does a cell quickly degrade a protein?
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It gets labelled with ubiquitin that attracts proteasomes to degrade (called polyubiquitination)
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How do antibiotics work?
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They interfere with the translation of prokaryotes
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What is contact inhibition?
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As soon as cells touch they stop replicating
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What plays the most important role in limiting cell replication?
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the telomere
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When cells are diving what is it called before they specialize? And after?
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Morula, then a Gastrula
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Where do stem cells establish?
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On the mesoderm
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What will happen to genes without a purpose put into an organism through recombinant DNA technology?
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it will eventually be lost throughout the generations
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What molecules are needed for PCR?
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DNA polymerase and nucleotides
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What bacteria are used to prevent DNA polymerase from denaturing?
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thermophilic bacteria (Taq)
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What is the technique of transfering gel information to nitrocellulose paper?
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Southern Blotting
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What blotting technique is used for RNA? For proteins?
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RNA-Northern Blotting
Proteins-Western Blotting |
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What are small DNA Probes made of and what is their purpose?
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They are made of radioactive nucleotides and are used to locate specific DNA on a blot
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What is autoradiography?
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When probes made DNA visible on a blot next to XRay film
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What is the hardest part of molecular biology?
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Figuring out the sequence of genes
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What molecules are involved in the Sanger Sequencing Method?
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dideoxyribonucleosides (missing an OH)
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RFLP = ?
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Restriction Fragment Length Polymorphism
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If you used a restriction enzyme on the human genome how many pieces would you get?
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about 6 billion
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What is a hypervariable microsatellite?
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a small part of DNA that can be used to tell people apart (used in forensics)
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What is a genomic library comprised of?
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Millions of recombinant DNA molecules in plasmids inserted into bacteria
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How is a cDNA library made?
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derived from mRNA using reverse transcriptase (so it has only exons)
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Denaturation of DNA can be done at what temperatures and pHs?
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100 degrees and 10-11 pH
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What is in situ Hybridization?
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Make naked DNA by removing the histones, denature the DNA, add the gene with a probe and see where it binds
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What do hemophilliac patients lack?
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Protein VIII (Factor F Protein)
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What is an expression vector?
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A plasmid carrying gene that is expressed by the bacteria
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What is a cloning vector?
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A plasmid carrying gene that is replicated by the bacteria
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What is the only way to make a transgenic animal?
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Introduce the genes into the gametes
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What time period did we learn a lot about the cell membrane?
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1960s-1970s
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What are all membranes made of?
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Phospholipids and proteins (different types and percentages)
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What is the most complex and important part of the cell?
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cell membrane
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What does the membranes structure allow it to do?
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Sense the physical environment
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How wide is the phospholipid bilayer?
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5 nm
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What is the head and the tail of a phospholipd made of?
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Head-glycerol and phosphoric acid
Tail-fatty acid |
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What does amphipathetic mean?
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One side if hydrophillic and the other hydrophobic
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What is a two-layered circle of phospholipids called?
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A liposome
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Where are membranes made?
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Smooth ER
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What are membranes made for?
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cell expansion, repair, new organelles
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What organelle specializes membranes?
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golgi
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What correctly positions proteins in the membrane?
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Flippase enzyme
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What are carbohydrates attached to peripheral proteins called?
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antenna molecules (or gycoproteins)
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the most common phospholipid has?
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choline
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How is the fluidity of the membrane increased?
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More unsaturated fatty acid tails (like in animals in cold regions)
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What molecule keeps the membrane stable?
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cholesterol
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What quality is the membrane?
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assymetric
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What are the 4 functions of proteins in the membrane?
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transporters, anchors, receptors, and enzymes
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What is the hydrate layer?
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The coating of carbohydrates on the cell surface that serve as recognition molecules
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What does the cell fusion experiment show?
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Protein lateral mobility in the membrane
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What is the phospholipid bilayer permeable to?
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small, hydrophobic molecules (such as O2, CO2, N2, H2O, gycerol, and ethanol)
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Which part of the membrane causes it to be semi-permeable?
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the hydrophobic tails
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How can water pass so quickly through the membrane?
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aquaporins
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Suction of Water =
|
Osmotic Pressure - Wall pressure
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How do protista get water out of the cell?
|
Vacuoles pump water out
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What are teh 3 types of passive transport?
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simple passive transport, carrier mediated, and channel mediated
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In animals about how much of the bodies energy is used for basal metabolism? And how much for active transport?
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basal metabolism-2/3
active transport-1/3 |
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How much oxygen is used for humans brain?
|
1/5
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How do channel and carrier mediated proteins specify between molecules?
|
shape and size
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What are the 3 types of active transport?
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coupled, ATP-drived, and light driven
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What does semi-permeable mean?
|
its only permeable to water
|
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What does osmotic pressure depends on?
|
molarity
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In dilute solutions what can affect osmotic pressure in addition to molarity?
|
number of ions
|
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What are the three types of proteins for glucose diffusion in red blood cells?
|
G1, G2, G3
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What are the three types of gates on channel gated proteins?
|
voltage gated, ligand gated, and mechanically gated
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What do plant, fungi, and bacteria have instead of a Na-K pump?
|
H+ pump
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What are the two driving forces in passive transport?
|
concentration gradeint and electrochemical gradient
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What cells can do pinocytosis and phagocytosis?
|
only specialized cells in animals
|