Genetics Exam 1

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Genetics Exam 1
2012-09-27 23:29:32
genetics exam

genetics exam 1
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  1. Genetics is the study of...
    finding the genotype that causes the phenotype
  2. The Genotypic function of a gene is
    Storage for genetic material so that it may be transmissable to the next generation
  3. Phenotypic function is...
    How genes control a phenotype
  4. Evolutionary function is when..
    genes mutate and organisms are able to evolve because the mutations can enhance adaptation
  5. You control phenotype through...
    gene expression
  6. Gene expression is when....
    gene turns into a gene product
  7. two example of gene products
    proteins and RNA
  8. The _________ actually does the function of the gene because the gene itself does not have function and needs to be expressed.
    gene product
  9. DNA is expressed by _______, to be converted into RNA
  10. 3 basic kinds of RNA are...
    • mRNA
    • tRNA
    • rRNA
  11. mRNA go through the extra step _________, to be made into a protein
  12. Reverese transcription is when _____ is translated back into _____.
    • RNA
    • DNA
  13. 3 types of genetic analysis are...
    • Mutation
    • Recombination
    • Complementation
  14. Mutation is a genetic analysis in which you...
    change a gene sequence or the regions that are controlling the gene, (physical change in gene sequence)
  15. Recombination is a genetic anaylsis that involves..
     a mixing up of DNA, (mixing genetic material)
  16. Complementation is a genetic analysis in which you...
    • make a gene whole.
    • (used after a recombinant or mutation, to restore normal function)
  17. The chemical definition of a gene is..
    in its Simplest form, the nucleotides in your DNA have a direct correlation with the nucleotides in the RNA and to the amino acids in the proteins.
  18. the functional definition of a gene is...
     Gene expression. The control of the gene.
  19. You can preform analysis by two methods, which are...
    screening and selection
  20. Analysis by screening is when ...
    All organisms are inspected, but you are looking for different phenotypes (change in phenotype) Everyone survives
  21. Analysis by selection is when...
    Everyone is killed off but a subset that survives.
  22. Posistive selection is when...
    the cells that are left will have the gene that you are interested in
  23. _____ are the most common source of mutations
    UV rays
  24. In order for a mutation to occur the change has to be....
    a transmissible change in gene sequence  or its controlling sequence
  25. A gene could look "normal" but the ______ around it might be mutated.
  26. Mot mutations kill the _____ of a gene
  27. most mutations are a loss of _______.
  28. mutations that kill the function of a gene are considered to be _________.
  29. Some mutations are dominant, so gene has a difficult function that overcomes the ______ of the normal gene
  30. Happens every time we have meiosis, and sometimes in mitosis
  31. We have ________ within our own cells, but you can also have it between external DNA and you (HIV).
  32. the most common from of recombination is
    Within an organism's genome
  33. external recombination is common in...
    • plants and those with HIV
    • (genome inserts into host genome)
  34. Complementation can be done by...
    adding the genetic material back (adding external DNA) or by mating of two mutants, so you can look for complementation
  35. complementation analysis is most common when you...
    • cross two mutants
    • (ex: melanin production)
  36. aaBBCC x AAbbCC

    What Is the genotype of the offspring?
    Offspring will be heterozygous for a and b and homozygous for c (aBC  x  AbC)
  37. Complementation analysis will give....
    Complementation analysis will give the minimum number of genes for some phenotypeuse lots of mutants
  38. A complementation group is...
    a gene
  39. If mutants are in the same gene they are in the same ________ group
  40. If mutants are in the same gene they can not...
    complementation group
  41. mutants in the same gene cannot complement each other because...
    they are in the same complementation group
  42. For complementation analysis to be possible each mutant
    must be __________ in 1 gene but ____________ in all others for the phenotype we are after.
    • homozygous recessive
    • homozygous dominant
  43. what are the four major chemicals in the gene structure?
    • Proteins
    • Nucleic Acids
    • Polysaccharides
    • Lipids
  44. A bacteriophage is...
    viruses that infect bacteria
  45. the T2 phage had a protein coat with _________ inside it
    nucleic acid
  46. In the hershey chase exp. sulfur 35 was used because it was only found in....
  47. In the hershey chase exp. Phosphorous 32 was used because it was mainly found in....
    nucleic acid
  48. Set 1 of the hershey-chase exp incuded hot ....
  49. Set 2 of the hershey-chase exp incuded hot ....
    nucleic acids
  50. What are the 4 steps of the hershey chase exp?
    • 1) phage* + bacteria
    • 2) blender -> slough off phage w/o lysing the bacteria(bacteria are infected with phage genes)
    • 3)centrifuge (phage -> in supernatant/ bacteria and phage genes-> in pellet)
    • 4) count supernatant and pellet
  51. in the hersey chase exp. ______ was in the pellet
  52. in the hersey chase exp. _____ was in the supernatant
  53. The hersey chase exp, shows us that ______ in genetical material.
    nucleic acid
  54. What are the building blocks of nucleic acids?
  55. The three parts to a nucleotide are...
    (base, sugar, a phosphate)
  56. the parts in a nucleoside are...
    Base and sugar
  57. the sugars parts in nucleic acids are either _____ or ____.
    deoxyribose or ribose
  58. The structure (shape) of a nucleic sugar is?

  59. number the carbons

  60. What is this?

  61. Number the carbons

  62. What is this?
  63. In ribose what are the hydroxyl groups numbered?
    3' and 2'
  64. In 2'deoxyribose what is the number of the prime hydroxyl?
  65. When the phosphates link to the sugar in nucelic acids, the phosphate group closest to the sugar is called...
  66. When the phosphates link to the sugar in nucelic acids, the phosphate group second closest to the sugar is called...
  67. When the phosphates link to the sugar in nucleic acids, the phosphate group third closest to the sugar is called...
  68. Each phosphate has a ____ charge on them
  69. What is responsible for the nucleic acid's charge?
  70. The bases of nucleic acids can either be a ______ or a ______
    • purine
    • pyrimidine
  71. The abbreviation for purines is...
  72. The abbreviation for pyrimidine is...
  73. Purines have ____ ring(s)
  74. pyrimidines have _____ ring(s)
  75. The two purines bases are...
    Adenine and guanine
  76. The two pyrimidine bases are...
    Cytosine and Thymine (Or Uracil if no methyl group)

  77. What is this?

  78. What is this?

  79. What is this?

  80. What is this?

  81. What is this?

  82. Which nitrogen attaches to the sugar?

  83. Which nitrogen does the sugar attach to?

  84. Which nitrogen attaches to the sugar?

  85. Which nitrogen does the sugar attaches to?

  86. Which Nitrogen does the sugar join at?
  87. a gene is a region that correlates with...
  88. Gene controlling regions are..
     Region outside of the area of transcription (upstream/downstream/both)
  89. Alpha phosphate from the __' of one sugar, gets connected to the __' OH of the other sugar
    • 5'
    • 3'
  90. ___________from the 5'of one sugar, gets connected to the 3' _______ of the other sugar
    • Alpha phosphate
    • OH
  91. the correct order in the DNA is from...
    From 3' OH to 5' Alpha Phosphate
  92. The correct way to write the nucleic acid sequence is...
    Left to right, 5' to 3'

    (in this sequence what is the 5' and 3')?
    • First G = 5' phosphate
    • Last T= 3' OH
  94. Complementary bases are..
    purines next to Pyrimidines, or vice versa, with hydrogen bonds.
  95. Guanine and cytosine have ____ bonds together
    3 Hydrogen
  96. Adenine and thymine have ______ bonds together
    Two Hydrogen
  97. DNA is almost always ______-stranded, Whereas RNA is almost always ______-stranded.
    • double
    • single
  98. DNA is a ___deoxyribose
  99. RNA is a ribose and has primes at positions
    2',3' and 5'
  100. DNA has thymine, While RNA has ....
  101. RNA has uracil while DNA has...
  102. Is DNA stable or unstable?
  103. Is RNA stable or unstable?
  104. What factor makes the difference in ribose stability?
    the ribose chemistry
  105. DNA is a double helix with ___ strands.
  106. DNA is ____-handed.
  107. The 5' to 3' Direction in DNA is.....
  108. DNA Strands are antiparallel or parallel?
    antiparallel or parallel
  109. The top DNA strand is always left to right ___ to ___
    5' to 3'
  110. the bottom DNA strand is always left to right ___ to ___
    3' to 5'
  111. What is important about the major and minor grooves in DNA?
    makes a difference to our gene expression where they are located and it also which proteins bind to it makes a difference.
  112. The three DNA types are...
    A,B and Z
  113. The main Type of DNA is type...
  114. If RNA base pairs with itself, the DNA form is...
  115. The B-form DNA is _____-handed.
  116. The A-form DNA is _____-handed.
  117. The Z-form DNA is _____-handed.
  118. Which form of DNA is most often found in double stranded regions of RNA?
  119. Which DNA form is more tightly wound?
  120. How is the Z-form DNA created?
    Created by separating the strands and making a double helix out of each single strand.
  121. Supercoil is..
    knots produced by further twisting of a helix
  122. If the supercoil is twisted in the sam direction of the helix it is called....
    • "+" Supercoil
    • (overwound)
  123. If the supercoil is twisted in the opposite direction of the helix it is called...
    • "-" supercoil
    • (underwound)
  124. _________ of a supercoil is needed to get to the bases to perform transcription and replication.
  125. The two physical properties of DNA are...
    • Hydrophobic interactions (base stacking)
    • Hydrogen bonds
  126. Hydrophobic interactions of DNA increases....
  127. Hydrophobic interactions of DNA increases entropy because...
    we get more disorder of water
  128. G-C pairs  are more stable than A-T or A-U because...
    G-C has more hydrogen bonds
  129. probability =
    (chance of 1 event) / (total possible events)
  130. The sum rule is used when you have a _____ event
  131. The probability rule you use when you have one choice or another (mutually exclusive) is...
    Sum Rule
  132. The different probabilities that can be added using the sum rule, should equal...
  133. The product rule is used when you have a _____ event
  134. The probability rule you use when you have a single event of independent choices that will both happen is...
    the product rule
  135. Conditional probability is...
    probability of an event when conditions are met
  136. Conditional probability formula=
    (probability of the event) / (probabililty of the condition)
  137. Multiple events have ___ choices per event.
  138. Binomial expansion predicts...
    the probability of an unordered combination of events
  139. Binomial expansion equation...
    P = (n!/s! t!) (psqt)
  140. in the binomial expansion, p stands for..
  141. in the binomial expansion, n stands for
    total # of events
  142. in the binomial expansion, s stands for...
    # of events with probability p
  143. in the binomial expansion, t stands for
    # of events with probability q
  144. in the binomial expansion, q stands for..
    the probability of the other category
  145. Each diploid can encode how many alleles for each different gene?
  146. What determines parentage?
    • locus
    • gene
    • alleles
    • MHC
  147. in parentage determination, the locus is the...
    position on the chromosome
  148. in parentage determination, the genes are found...
    at one locus
  149. in parentage determination, alleles are...
    multiple forms of the same gene found on the same chromosomes
  150. MHC stands for...
    major histocompatibility complex
  151. the function of the MHC is to...
    encode proteins on cell surfaces
  152. The humans MHC consists of/is called...
    HLA proteins
  153. HLA stands for...
    Human Leukocyte entigen
  154. HLA proteins are found...
    on our cell surfaces
  155. HLA allows cells to...
    interact with the immune system
  156. What happens if HLA is not recognized properly....
    autoimmune diseases occur
  157. theres a multiple of ___ HLA genes
  158. Each HLA gene have ____ of alleles
  159. The reason why transplants don't work is because...
    each HLA gene has lots of alleles
  160. in _________, there are many combinations of HLA genes
  161. are alleles randomly distributed?
  162. ________ are most likely to have most of the same alleles as you.
    family members
  163. Donors, NEVER macthes your _____ entirely.
  164. The effect you see in a dominant gene is...
    the effect of dominant whether mutant or normal
  165. the diversity of mechanisms by which alleles affects traits depends on what four factors?
    • 1) individuals sex
    • 2) Level of protein expression
    • 3) Presence of multiple genes
    • 4) environmental effects
  166. A dominant negative gene is a gene that
    interferes negatively with action of normal gene product.
  167. an example of a dominant negative gene is....
    huntington's chorea
  168. the example of dominant genes is..
    ear wax
  169. dominant negative genes only make a difference if you are...
  170. the mutation in the huntington's chorea is necessary for ____ function.
  171. the normal and mutant geness in huntington's chorea are...
  172. the mutant in huntington's chorea interferes with...
    normal neuoronal function
  173. in incomplete/partial dominance, the heterozygotes, phenotype is different from...
    either homozygote
  174. in incomplete/partial dominance, the phenotype of the progeny  is...
    in between (intermediate)
  175. in codominance, the heterozygote phenotype is different from the...
    homozygote phenotytpe
  176. dominance depends on the...
    level of inspection
  177. organismal level dominance =
  178. cellular level dominance =
    incompletely dominant
  179. molecular level dominance =
  180. homozygotes have no dominance....
  181. Sequential dominace have...
    multiple alleles
  182. Pleiotrophy is when...
    one gene has multiple phenotypes
  183. Most lethal genes are...
  184. Example of the lethal gene is...
    the Manx cat. (Mm=tail-less), (mm=spineless and dead)
  185. Penetrance is...
    the percentage of individuals with the genotype that express the phenotype.
  186. the Retinoblastoma gene is a....
    tumor suppressing gene.
  187. 90% of people who are heterozygous for retinoblastoma get
    eye cancer
  188. 90% of the time, 90% of individuals mutate the normal copy of the_________  gene.
  189. ______ is our most common mutagen
    U.V light
  190. In conditional mutations, the function of the gene product is affected by...
    the environment
  191. XY =
  192. XX=
  193. ZW=
    female birds
  194. ZZ=
    Male birds
  195. What chromosomes are not present in bees?
  196. female bees are ______ and males bees are _____.
    • diploid
    • haploid
  197. in the fruitfly "Y" does not...
    determine "male"ness
  198. XX/2=
    Female fruitflies
  199. X/2=
    male fruitflies
  200. Dosage compensation is when...
    everyone gets the same amount of gene product
  201. dosage compensation in flies are...
    Male specific protein that doubles the expression of X
  202. dosage compensation in mammals are..
    • X-inactivation (only happens if you have
    • more than one X) (Embryonic around day 12)Females are mosaic for there X chromosomes (gene products).
  203. dosage compensation for cats are...
    (Xo Xb -> either a mix of orange and black or calico cats)
  204. every calico cat is a ....
  205. a random re-inactivated X is called a ....
    barr body
  206. Y chromosome determines maleness because
    it contains an SRY (sex region on the Y= Contains TDS, testes determining factor.)
  207. a Pseudo autosomal region is a...
    Y evolved from X that still has some "X" on it.
  208. pseudo autosomal regions are necessary for...
  209. sex-linked genes are...
    genes on the chromosome
  210. Sex-linked genes are found on ....
    only one type of sex chromosome
  211. Hemizygous genes is when...
    you only have 1 allele in a genome
  212. males are hemizygous because
    they only have one X chromosome - XY
  213. Holandric genes are..
    genes that are on the Y chromosome.
  214. Sex-limited genes are..
    genes that everybody has, autosomals expressed by one sex. (ex. Everyone can make ovaries)
  215. sex-influeneced genes are...
    autosomal genes, but their expression is affected by the gender of the organism. (male patterned baldness)
  216. Epitasis is...
    multiple gene for one phenotype
  217. complementary epitasis is when....
    multiple different genes code for the same phenotype. (melanin production)
  218. Duplicate epistasis is when you have...
    multiple copies of the same gene
  219. 3 types of non-medelian genetics (inheritance) are...
    • internal/maternal effect
    • epigenetic inheritance
    • extra-nuclear inheritance
  220. in early development there is no...
  221. All of the mRNA in early development are from ...
    the female egg
  222. Early development in phenotypes depend upon...
    the mother's genotype
  223. if the mRNA carrys recessive genes the phenotype of the children will be
    the recessive gene
  224. epigenetic inheritance is when you have...
    chemical modification of the chromosome
  225. the DNA sequence in epigenetic inheritance is the same, but the _____ changes.
  226. When you modify DNA you are turning off...
    it's expression of that gene, most of the time
  227. Turning off the gene expression happens alot in ...
    somatic cells
  228. turning off the gene expression in gametes are...
  229. the two types of epigenetic inheritance are...
    • dosage compensation
    • genomic imprinting
  230. genomic imprinting is when...
    Sex-specific DNA modifications occur during gametogenesis
  231. gametogenisis process...
    • 1) strip off prior modifications (de-methylated) 
    • 2) re-modify in a sex-specific way
  232. female genes in mice are...
  233. extra-nuclear inheritance deals wof..ith the DNA
    Organelles (mitochondria, chloroplasts)
  234. Organalles included in extra-nuclear inheritance, encode all ______ and _____ necessary for translation within organelles.
    tRNA and rRNA
  235. in extra-nuclear inheritance, a few essential _____ can be ecoded.
  236. the mRNAs in extra-nuclear inheritance are usually ______ in heritance
  237. a karyotype is...
    whole set of chromosomes in nucleus
  238. Each chromosome has a ...
  239. if the centromere is at the middle position it is called...
  240. if the centromere is at an end position it is called...
    telo-centric or acro-centric
  241. short arm=
  242. long arm=
  243. somatic cell chromosomal changes (aoterations) are...
    not heritable (may be cancerous)
  244. germ cell chromosomal changes are....
  245. 5 types of chromosomal changes are...
    • duplication
    • indel
    • inversions
    • SNPs
    • translocations
  246. 3 types of duplications are...
    • tandem
    • reverse
    • displaced
  247. -> -> duplication =
  248. -> <- duplication =
  249. displaced duplication =
    far seperated even on different chromosome.
  250. Indel =
    insertion or deletion
  251. Inversions is when....
    you break off a piece of chromosome, turn it around (change orientaiton) then stick it back on
  252. SNPs stand for...
    Small nucletoide polymorphisms
  253. SNPs are..
    single nucleotide changes/mutations
  254. translocations are...
    exchanges between chromosomes
  255. the four types of translocations are...
    • reciprocal
    • non-reciprocal
    • balanced
    • unbalanced
  256. reciprocal translocation is...
    a trade of chromosomal fragments
  257. non-reciprocal translocation is...
    no trade of chromosomal fragments (usually a fusion)
  258. a balanced translocation is...
    no change in the amount of genetic material
  259. an unbalanced translocation is...
    a change in the total amount of genetic material
  260. what two things can cause an unblanced translocation?
    deletion or duplication
  261. What are four types of mechanisms?
    • recombination
    • chromosomal breaks
    • insertions
    • single-base mutations
  262. recombination is when...
    you have an exchange of genetic material
  263. chromosomal breaks is caused ...
    when we're exposed to high energy (x-rays)
  264. insertions are when...
    • foreign things will insert into genome host,
    • (like transposons that transpose their selves)
  265. single-base mutations are caused by...
    • the environment
    • chemicals we eat
    • light
    • mistakes in replication
  266. duplications are a source of...
  267. A paralog is...
    two different genes (that will probably) form duplication
  268. Homologs are...
    genes in different organisms that are probably evolved from the same ancestor.
  269. deletions can result in..
  270. pseudodominance is...
    deleted one gene, so only have one gene that’s recessive, but now apparently dominant due to deletion of other gene.
  271. pseudodominance is when you have ______ instead of normal two...
    one copy of a gene
  272. deletions/psedodominance can be used for...
    location mapping (gene location identification)
  273. Two kinds of inversions are..
    • paracentric
    • paricentric
  274. paracentirc inversion is...
    inversion does not include the centromere
  275. paricentric inversion is...
    inversion does include the centromere
  276. Robertsonian translocation is...
    Non reciprocal translocation where two chromosomes fuse at their centromeres.
  277. in Robertsonian translocation you keep...
    one centromere and the other goes away
  278. Robertsonian translocation can happen in what types of cells?
    • somatic
    • germ
  279. fusion between chromosomes 14 and 21 results in...
    familial down syndrome
  280. fusion between chromosomes 14 and 21 has to happen in...
    the gametes
  281. inherited down syndrome is when you have...
    3 copies of chromosomes 21
  282. translocation in somatic cells is...
    the philadelphia chromosome
  283. the philadelphia chromosome is when you have a reciprocal between...
    9 & 22
  284. hematopoietic stem cells are involved in...
    chronic leukemia
  285. five kinds of changes in ploidy are...
    • eupolid
    • aneuploid
    • polyploid
    • autopolyploid
    • allopolyploid
  286. euploid variants=
    changes in whole number of sex
  287. aneuploid=
    changes in less than whole sets
  288. polyploid=
    greater than two sets of chromosomes
  289. autopolyploid=
    multiple sets from the same species
  290. allopolyploid=
    multiple sets are from different species
  291. sex chromosomal nomenclature...
    # of chromosomes, sex chromosomes, + /- a particular chromosome

    • (46,XX, 46 XY)
    •  47 XY + 21(<---extra chromosome)
  292. Large salmon over express...
    growth hormone
  293. large salmon are ____ while normal salmon are diploid.
  294. triploidy makes large salmon
    effectively sterile
  295. haploid salmon = ____ chromosomes
  296. female salmon = ___ eggs
  297. Autosomal gene is...
    the gene responsible for the phenotype is located on one of the 22 pairs of autosomes (non sex-determining chroosomes)
  298. X-linked gene is...
    the gene that encodes for the trait is located on the X chromosome.
  299. if you have an autosomal dominant pedigree, affected indivual have one _______ of the gene and one _______ of the gene.
    • Normal copy
    • mutant copy
  300. if you have an autosomal dominant pedigree, each offspring has a ____ chance of inheriting the mutant allele.

  301. what type of disease is this?
    autosomal dominant
  302. in a pedigree with an autosomal recessive disease when two carriers mate each child has a ____ chance of being homozygous wild-type, a ____ chance of being homozygous mutant or a ____ chance of being heterozygous.
    • 25%
    • 25%
    • 50%
  303. homozygous wildtype in an autosomal recessive  are...
  304. homozygous mutants in an autosomal recessive are...
  305. heterozygous in the autosomal recessive makes you...
    an unaffected carrier

  306. what type of disease is this?
    autosomal recessive
  307. All X-linked recessive traits are fully evident in males because....
    they only have one copy of the X chromosome
  308. Women are rarely affected by X-linked recessive diseases because...
    they have two X chromosomes
  309. Because the X-linked recessive gene is on the X chromosome there is no ________ transmission
    father to son
  310. in x-linked recessive genes, the father can transmit to..
  311. in x-linked recessive genes, the mother can transmit to...
    daughter and son
  312. If a man is affected with an X-linked recessive condition, all his daughters will inherit....
    one copy of the mutant allele from him.

  313. What type of disease is this?
    X-linked recessive
  314. In the x-linked dominant gene, Because the gene is located on the X chromosome, there is no transmission from father to....
  315. In X-linked dominant, all daughters of an affected male will be affected since....
    the father has only one X chromosome to transmit
  316. In the x-linked dominant, Children of an affected woman have a ____ chance of inheriting the X chromosome with the mutant allele

  317. What type of disease is this?
    X-linked Dominant
  318. huntington disease and acondroplasia are ___________ conditions.
    autosomal dominant
  319. 1% Recombination = ____ map unit(s)
  320. Two ways to find recombinants (recombinant progeny ID) is?
    • Looking at the phenotype
    • Looking at the numbers
  321. Recombinants do not have the same ________ as the grandparents.
  322. Recombinants are less ______ than non-recombinants
  323. What is an example of multiple gene mapping?
    3 point cross map
  324. In multiple gene mapping, the _____ gene moves.
  325. in recombinants, Big numbers are the genes that did not....
  326. in recombinants, Small numbers are the genes that ....
  327. The least frequent progeny in a 3 pt. cross are ....
    the double recombinants
  328.  (+++/y vg w) these are....
    parental chromosomes
  329. (++w/yvg +) these are...
    double recombinants
  330. Parental chromosomes (+++/yvg w)
    Double recombinants (++w/y vg+)

    What is the gene order?
    (y w vg)

    *middle always moves*
  331. Interference is...
    • when crossovers interfere with each other, the
    • closer they are
  332. Interference equation=
    1 - (observed double recombinants/expected double recombinants)
  333. The ______ the genes are, the more interference they have.
  334. Measure of interference called....
    coefficient of coincidence
  335. for close genes, I approaches ...
  336. for far genes, I approaches...
  337. Neurospora has __haploids of opposite mating types
  338. what has 2 haploids of opposite mating type?
  339. In neurospora, cells ____ creating __ spores
    • fuse
    • 8
  340. If recombination happed before replication, all the spores....
  341. If recombination happens before meiosis(what amount of genes are recombined?)
    • Half spores look like parental
    • Other half recombined
  342. If recombination happens after meiosis(what amount of genes are recombined?)
    All spores will look the same
  343. What kind of recombination causes red-green color blindness?
    non-reciprocal recombination (unequal)
  344. when you have unequal (non-reciprocal) recombination, products are different....
  345. can you determine the maximum number of genes involved in a phenotype?
  346. Why can't you determine the maximum number of genes involved in a phenotype?
    we can never be sure that we have isolated a mutant in every gene involved
  347. What are the building blocks of a nucleotide?
    • a nitrogenous base
    • a sugar (deoxyribose or ribose)
    • a phosphate group
  348. With regard to the 5ʹand 3ʹ positions on a sugar molecule, how are nucleotides linkedtogether to form a strand of DNA?
    The phosphate group is already linked to the 5' position on the sugar in one nucelotide. That nucleotide has a covalent bond with the 3' hydroxyl group on another nucleotide.
  349. What parts of a nucleotide occupy the major and minor grooves of double-stranded DNA?
    The nucleotide bases
  350. What parts of a nucleotide are found in the DNA backbone?
    Phosphate and sugar
  351. If a DNA binding protein does not recognize a specific nucleotide sequence,do you expect that it recognizes the major groove, the minorgroove, or the DNA backbone?
    If a DNA-binding protein does not recognize a nucleotide sequence, it is not binding in the grooves but instead is binding to the DNA backbone.
  352. Why would a DNA-binding protein that does not recognize a nucleotide sequence bind to the DNA backbone instead of the  grooves?
    because a nucleotide sequence consists of nucleotide bases. The protein will choose the alternative which is the backbone because it has phophates and sugars as opposed to the nucleotide bases.
  353. DNA-binding proteins that recognize a bas esequence must bind into a...
    major or minor groove of the DNA
  354. In a DNA doublehelix, what does the term antiparallel mean?
    Antiparallel means that the backbones are running in the opposite direction. In one strand, the sugar carbons are oriented in a 3' to 5' direction, while in the otherstrand they are oriented in a 5' to 3' direction.
  355. If you knew that a DNA-binding protein was recognizing the DNA backbone rather than base sequences, which amino acids in the protein would be good candidates for interacting with theDNA?
    The positive amino acids (Lysines and Arginines) and polar amino acids because it will attract to the negatively charged back bone.
  356. Would single stranded genetic material contain equal amounts of A andT and equal amounts of G and C?
    No, because the AT/GC rule is required only of double-stranded DNA molecules.
  357. Why were 32P and 35S chosen as radioisotopes to label thephages in the Hershey Chase experiment?
    because phosphorous is found in nucleic acids, while sulfur isfound only in proteins.
  358. Describe the characteristics of highly repetitive DNA.
    • is a DNA sequence thatis repeated many times, throughout the genome.
    • It can be interspersed in the genome or foundclustered in a tandem array
    • renatures at a much faster rate
  359. Highly repetitive DNA renatures at a much faster rate because..
    there are many copies of the complementary sequences.
  360. A tandem array is...
    a short nucleotide sequence isrepeated many times in a row.
  361. With regard to genotypes, what is a true-breeding organism?
    A homozygote that has two copies of the same allele
  362. suppose a recessive allele encodes a completely defectiv eprotein. If the functional allele is dominant, what does that tell you about the amount of the functional protein that is sufficient to cause the phenotype?
    that one copy of the geneproduces a sufficient amount of the protein encoded by the gene.Having twice as much of this protein, as in the normal homozygote,does not alter the phenotype
  363. suppose a recessive allele encodes a completely defectiv eprotein. If the functional allele is incompletely dominant, what does that tell you about the amount of the functional protein that is sufficient to cause the phenotype?
    that one copy of the normal allele does not produce the same trait as the homozygote.
  364. Assuming that such a fly would be viable, what would be the sex of a fruit fly with the following chromosomal composition?

    One X chromosome and two sets of autosomes
    The fly is a male because the ratio of X chromosomes to sets of autosomes is 1/2, or 0.5.
  365. Assuming that such a fly would be viable, what would be the sex of a fruit fly with the following chromosomal composition?

    Two X chromosomes, one Y chromosome, and two sets ofautosomes
    The fly is female because the ratio of X chromosomes to sets ofautosomes is 1.0.
  366. Assuming that such a fly would be viable, what would be the sex of a fruit fly with the following chromosomal composition?

    Two X chromosomes and four sets of autosomes
    The fly is male because the ratio of X chromosomes to sets ofautosomes is 0.5.
  367. Assuming that such a fly would be viable, what would be the sex of a fruit fly with the following chromosomal composition?

    Four X chromosomes, two Y chromosomes, and four sets of autosomes
    The fly is female because the ratio of X chromosomes to sets of autosomes is 1.0.
  368. Describe the inheritance pattern of maternal effect genes...
    A maternal effect gene is one in which the genotype of the motherdetermines the phenotype of the offspring.
  369. Explain how the maternal effect occurs at the cellular level.
    this happens because maternal effect genes are expressed in diploidnurse cells and then the gene products are transported into the egg.
  370. What are the expected functional roles of the proteins that are encoded bymaternal effect genes?
    These gene products play key roles in the early steps of embryonicdevelopment.
  371. Suppose a maternal effect gene exists as a normal dominant allele and an abnormal recessive allele. A mother who is phenotypicallyabnormal produces all normal offspring. Explain the genotype ofthe mother...
    • The mother must be heterozygous.
    • She is phenotypically abnormal because her mother must have been homozygous for the abnormal recessive allele.
    • Because she produces all normal offspring,she must have inherited the normal dominant allele from her father.
    • She produces all normal offspring because this is a maternal effect gene, and the gene product of the normal dominant allele is transferred to the egg.
  372. How many Barr bodies would you expect to find in humans withthe following abnormal composition of sex chromosomes?

  373. How many Barr bodies would you expect to find in humans with the following abnormal composition of sex chromosomes?

  374. How many Barr bodies would you expect to find in humans with the following abnormal composition of sex chromosomes?

  375. How many Barr bodies would you expect to find in humans with the following abnormal composition of sex chromosomes?

    X0 (single x chromosome)
  376. A black female cat (XBXB) and an orange male cat (X0 Y) weremated to each other and produced a male cat that was calico.Which sex chromosomes did this male offspring inherit from its mother and father?
    The offspring inherited XB from its mother and XO and Y from itsfather. It is an XXY animal, which is male (but somewhat feminized).
  377. As a hypothetical example, a trait in mice results in mice with verylong tails. You initially have a true-breeding strain with normal tails and a true-breeding strain with long tails. You then make thefollowing types of crosses:

    Cross 1: When true-breeding females with normal tails are crossedto true-breeding males with long tails, all F1 offspring have longtails.

    Cross 2: When true-breeding females with long tails are crossedto true-breeding males with normal tails, all F1 offspring havenormal tails.

    Cross 3: When F1 females from cross 1 are crossed to truebreedingmales with normal tails, all offspring have normal tails.

    Cross 4: When F1 males from cross 1 are crossed totrue-breeding females with long tails, half of the offspringhave normal tails and half have long tails.

    Explain the pattern of inheritance of this trait.
    The pattern of inheritance is consistent with imprinting. In every cross, the allele that is inherited from the father is expressed in the offspring, but the allele inherited from the mother is not.
  378. Two phenotypically normal parents produce a phenotypically abnormal child in which chromosome 5 is missing part of its long arm but has a piece of chromosome 7 attached to it. The child also has one normal copy of chromosome 5 and two normal copies of chromosome 7. With regard to chromosomes 5 and 7, what do you think are the chromosomal compositions of the parents?
    One of the parents may carry a balanced translocation betweenchromosomes 5 and 7. The phenotypically abnormal offspring has inherited an unbalanced translocation due to the segregation oftranslocated chromosomes during meiosis.
  379. A person is born with one X chromosome, zero Y chromosomes,trisomy 21, and two copies of the other chromosomes. How many chromosomes does this person have altogether? Explain whether this person is euploid or aneuploid.
    This person has a total of 46 chromosomes. However, this person would be considered aneuploid rather than euploid, because one ofthe sets is missing a sex chromosome and one set has an extra copy ofchromosome 21.
  380. Which of the following terms should not be used to describe ahuman with three copies of chromosome 12?

    A. Polyploid
    B. Triploid
    C. Aneuploid
    D. Euploid
    E. 2n + 1
    F. Trisomy 12
    Polyploid, triploid, and euploid should not be used.
  381. The karyotype of a young girl who is affected with familial Down syndrome revealed a total of 46 chromosomes. Her olderbrother, however, who is phenotypically unaffected, actually had45 chromosomes. Explain how this could happen. What would you expect to be the chromosomal number in the parents of these twochildren?
    The boy carries a translocation involving chromosome 21: probably a translocation in which nearly all of chromosome 21 is translocatedto chromosome 14. He would have one normal copy of chromosome14, one normal copy of chromosome 21, and the translocated chromosome that contains both chromosome 14 and chromosome 21.This boy is phenotypically normal because the total amount of geneticmaterial is normal, although the total number of chromosomes is 45(because chromosome 14 and chromosome 21 are fused into a singlechromosome). His sister has familial Down syndrome because shehas inherited the translocated chromosome, but she also must haveone copy of chromosome 14 and two copies of chromosome 21. Shehas the equivalent of three copies of chromosome 21 (i.e., two normalcopies and one copy fused with chromosome 14). This is why she has familial Down syndrome. One of the parents of these two childrenis probably normal with regard to karyotype (i.e., the parent has 46normal chromosomes). The other parent would have a karyotype thatwould be like the phenotypically normal boy.

  382. What is the outcome of this single crossover event? If a second crossover occurs somewhere between A and C, explain which two chromatids it would involve and where it would occur (i.e.,between which two genes) to produce the types of chromosomes shown here:

    A. A B C, A b C, a B c, and a b c
    B. A b c, A b c, a B C, and a B C
    C. A B c, A b c, a B C, and a b C
    D. A B C, A B C, a b c, and a b c
    A single crossover produces A B C, A b c, a B C, and a b c.

    • A. Between 2 and 3, between genes B and C
    • B. Between 1 and 4, between genes A and B
    • C. Between 1 and 4, between genes B and C
    • D. Between 2 and 3, between genes A and B
  383. In humans, a rare dominant disorder known as nail-patella syndromecauses abnormalities in the fingernails, toenails, and kneecaps. Researchers have examined family pedigrees with regard tothis disorder and, within the same pedigree, also examined theindividuals with regard to their blood types. (A description ofblood genotypes is found in Chapter 4 .) In the following pedigree,individuals affected with nail-patella disorder are shown with filled symbols. The genotype of each individual with regard to their ABO blood type is also shown. Does this pedigree suggest any linkage between the gene that causes nail-patella syndrome and thegene that causes blood type?

    The pedigree suggests a linkage between the dominant allele causingnail-patella syndrome and the IB allele of the ABO blood type gene. Inevery case, the individual who inherits the IB allele also inherits thisdisorder.
  384. Except for fungi that form asci, in most dihybrid crosses involving linked genes, we cannot tell if a double crossover between the two genes has occurred because the offspring will inherit the parental combination of alleles. How does the inability to detect doublecrossovers affect the calculation of map distance? Is map distance underestimated or overestimated because of our inability to detect double crossovers?
    The inability to detect double crossovers causes the map distance to be underestimated. In other words, more crossovers occur in the region than we realize. When we have a double crossover, we do not get are combinant offspring (in a dihybrid cross). Therefore, the second crossover cancels out the effects of the first crossover.
  385. Two genes are located on the same chromosome and are known tobe 12 mu apart. An AABB individual was crossed to an aabb individualto produce AaBb offspring. The AaBb offspring were thencrossed to aabb individuals.

    A. If this cross produces 1000 offspring, what are the predictednumbers of offspring with each of the four genotypes: AaBb,Aabb, aaBb, and aabb?

    B. What would be the predicted numbers of offspring with these four genotypes if the parental generation had been AAbb and aaBB instead of AABB and aabb?
    A. Because they are 12 mu apart, we expect 12% (or 120) recombinantoffspring. This would be approximately 60 Aabb and 60 aaBb plus440 AaBb and 440 aabb.

    B. We would expect 60 AaBb, 60 aabb, 440 Aabb, and 440 aaBb.