Genetics exam #1

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Genetics exam #1
2013-09-18 11:04:03
genetics class 10

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  1. linear chromosomes in nucleus are bound by
    a nuclear membrane
  2. the eukaryotic cell has a plasma membrane, no cell wall
  3. this kind of cell has complicated internal membrane structures
    eukaryotic cell
  4. what 2 things do the mitochondria and chloroplast do as organelles
    • contain small circular DNA molecules
    • synthesize many of their own proteins
  5. the prokaryotic cell is found in these two domains
    • bacteria
    • archae
  6. how do prokaryotic cells divide
    by binary fission
  7. 3 characters of bacteria cells
    • smaller than eukaryotic cells
    • have a peptidoglycen cell wall with a plasma membrane
    • singular circular chromosome
  8. bacteria cell has a singular circular chromosome condensed into a
  9. sister chromatids
    replicated chromosomes
  10. centromere
    joins the sister chromatids
  11. each chromatid contains an identical single double stranded dna molecule
  12. the centromere contains a protein structure called a
  13. kinetochore function
    required for movement to the poles during cell division
  14. centromeres can lie anywhere along the length of a chromosomes
  15. telomeres
    the ends of the chromosomes
  16. metacentric
    centromere location is in the middle of the two sister chromatids
  17. submetacentric
    centromere between the middle and end of the chromosomes
  18. acrocentric
    centromere closer to the end of the chromosome
  19. telocentric
    centromere at the end of the chromsome
  20. 2 occurances between G1 phase
    • cell mass increase
    • prep for S phase
  21. S phase
    DNA replication (synthesis)
  22. What happens in S phase
    each chromosomes in the interphase nucleus is duplicated, generating two sister chromatids
  23. 2 occurances of G2 phase
    • growth
    • prep for mitosis
  24. in diploid organisms, chromosomes occur in pairs known as
  25. where do the homologs come from in diploid organisms
    one homolog from each parent during fertilization
  26. after meiosis, how many chromosomes are in each gamete
    • half of the number of chromosomes
    • (haploid)
  27. 3 things that happen in M phase
    • sister chromatids separate from each other and enter into newly formed daughter cells
    • karyokinesis then cytokinesis
    • each cell receives a sister chromatid from each chromosome
  28. what phase do chromosomes not able to be distinguished
  29. when is the centrosome duplicated
    S phase
  30. Centrosome contains centrioles in animal cells
  31. function of the copied centrosome
    acts as a microtubule organizing center and functions as the spindle pole during mitosis
  32. the pair of centrioles at the center replicate and then separate as microtubules radiate outward forming an aster
  33. during what phase do microtubules attach to the kinetochores at the centromeres
  34. what is the function of the microtubules when they attach to the kinetochores
    guide the sister chromatid separation
  35. only fully condensed chromosomes move to the metaphase plate
  36. what phase does the chromosomes line up on the central equatorial plates between the centrosome plates
  37. 3 occurances during prophase
    • 2 centrosomes move to opp sides of the cell
    • replicated chromosomes begin condensing, sister chromatids become visible
    • nuclear membrane fragments and nucleolus disperses
  38. disjunction
    the splitting of centromeres of the sister chromatids separate to opp poles via microtubule shortening
  39. 5 occurrences of telophase
    • chromosomes stop moving to opp poles
    • microtubules disassemble
    • nuclear membrane reforms
    • nucleolus reappears
    • chromosomes decondense
  40. once the cells are done in telophase they enter G1 and interphase
  41. 5 stages that occur in prophase I
    • Leptonema
    • Zygonema
    • Pachynema
    • Diplonema
    • Diakinesis
  42. leptonema stage
    replicated chromosomes appear as a single threadlike structure
  43. zygonema stage
    chromosomes continue condensing and homologs pair to form bivalents
  44. bivalent def in meiosis
    the pairing of chromosomes
  45. when does the synaptonemal complex form
  46. ladder like structure formed in zygonema
    synaptonemal complex
  47. pairing at various sites in prophase I
  48. 3 things that occur during pachynema
    • SC further develops
    • paired homologs resolve into replicated chromosomes, each containing a pair of sister chromatids
    • crossing over occurs
  49. tetrads
    paired homologs
  50. diplonema stage
    homologs desynapse and repel from each other but remain attached at the chiasmata
  51. Chiasmata
    the location in which crossing over took place
  52. 3 things that occur in diakinesis stage
    • chiasmata move toward ends of tetrads
    • nuclear membrane and nucleolus disperse
    • microtubules attach to the kinetochore
  53. terminalization initiated in diplonema completes in diakinesis
  54. terminalization
    the movement of transverse bonds between paired chromosomes in meiosis from their points of origin toward the ends of the chromosomes
  55. a diploid cell has 6 chromosomes. During mitosis, how many chromosomes are observed during anaphase
  56. a diploid cell has 6 chromosomes. During meiosis, how many chromosomes are observed during anaphase I
  57. 3 reasons why mendel chose garden peas as his model organism
    • easy to grow
    • crossbred artificially or self fertilized
    • grows to maturity in one season
  58. seven pairs of contrasting traits were considered
    true breeding
  59. what 2 things did mendel do
    • determined that discrete units of inheritance exist
    • predicted their behavior during the formation of gametes
  60. 7 traits that were contrasted
    • seed shape
    • seed color
    • pod shape
    • pod color
    • flower color
    • flower position
    • stem height
  61. seed shape contrast
    seed color contrast
    pod shape contrast
    pod color contrast
    flower color contrast
    flower position contrast
    stem height contrast
    • rounded/wrinkled
    • yellow/green
    • full/constricted
    • green/yellow
    • violet/white
    • axial/terminal
    • tall/dwarf
  62. how mendel cross fertilized plants
    • mixed a white flower with a violet flower
    • removed anthers from violet flower plant
    • brushed pollen from white flower plant to stigma of violet flower plant
    • pollen enters stigma, moves down pistil to ovary to fertilize eggs
  63. genes
    products that direct metabolic activities of cells
  64. DNA has an underlying linear structure that possesses segments called
  65. DNA and its array of genes are organized into structures called
  66. chromosomes
    serves as vehicles for transmitting genetic info
  67. meiosis is a type of cell division that gives rise to two types of sex cells
    • gametes
    • spores
  68. chromatin
    genetic material that make up chromosomes that is unfolded and uncoiled into a diffuse network
  69. all cells are surrounded by
    plasma membrane
  70. plasma membrane
    outer covering that defines the cell boundary and protects the cell from the outer environment
  71. the cell wall in plant cells are made up of
  72. sometimes animal cells have a cover over the plasma membrane called
    glycocalyx (cell coat)
  73. 2 purposes of glycocalyx
    • biochemical identity at the surface of cells
    • establish cellular identity at the surface of the cells
  74. where are receptor molecules found
    surface of cells
  75. receptor molecules function
    act as recognition sites that trasnfer specific chemical signals across the cell membrane into the cell
  76. where is rRNA synthesized and ribosomes are assembled
  77. nucleolus organizer region
    portions of DNA that encode rRNA
  78. in the cytoplasm, the material that makes up it is called
  79. microtubules are made up of the protein
  80. microfilaments are made up of the protein
  81. functions of the ER
    site for synthesizing fatty acids and phospholipids
  82. ribosome function
    sites where genetic info contained in the mRNA is translated into proteins
  83. centrioles are located in the
  84. centrioles function
    are associated with the organization of spindle fibers in mitosis/meiosis
  85. sometimes centrioles are derived from the basal body
  86. the short arm of the chromosomes
    the longer arm of the chromosomes
    • p arm
    • q arm
  87. 2 chromosomes that pair up
    homologous chromsomes
  88. genome
    all of the genetic info contained in a set of chromosomes
  89. locus
    location of a gene on the chromosome
  90. biparental inheritance
    inheritance from 2 parents
  91. alleles
    alternative forms of genes
  92. karyokinesis
    the equal breaking up of genetic material between daughter cells
  93. 2 pathways a cell can take in the G1 phase
    • withdraw from cycle and enter G0
    • continue through G1 and go to S phase
  94. shugoshin
    protects cohesion from being degraded by separase at centromeric regions
  95. 3 things need to occur in order for disjunction to complete
    • shguoshin must be degraded
    • cohesion complex is cleaved by separase
    • sister chromatids are pulled to opp sides
  96. chromosome migration results from the activity of a series of molecules called
    molecular motors
  97. what do molecular motor need in order to function
    use energy generated by hydrolysis of ATP
  98. what do molecular motors do
    affect microtubules by shortening the spindle fibers drawing chromosomes to opp sides of the cells
  99. middle lamella
    cell plate that lays down during telophase
  100. cyclins bind to
  101. function of cyclins
    activate kinases at appropriate times during the cell cycle
  102. function of the G1/S checkpoint
    monitors the size the call has achieved and evaluates the DNA condition
  103. function of G2/M checkpoint
    DNA is monitored prior to the start of mitosis
  104. when a tetrad separates, two homologs that separate, it yields
  105. 2 sister chromatids joined at a common centromere
  106. when dyads split it yields
  107. homology search, precedes and is essential to the initial pairing of homologs occurs in what stage in prophase I
  108. chromosomes begin to shorten and thicken in this stage of prophase I
  109. synaptonemal complex
  110. this is believed to be the vehicle responsible for the pairing of homologs
    synaptonemal complex
  111. chiasma
    the area in which crossing over occured
  112. nondisjunction
    errors in meiosis and occur and separation is not achieved
  113. spermatogenesis
    production of male gametes
  114. oogenesis
    production of female gametes
  115. spermatogenesis begins with the enlargement of an undifferentiated diploid germ cell called
  116. sperm cell that is grown and used in meisis
  117. secondary spermatocyte
    products of the first division
  118. when the secondary spermatocytes undergo meiosis II, each of the cells produce
    2 haploid spermatids
  119. spermiogenesis
    spermatids go through a series of developmental changes to become specialized sperm
  120. oogensis
    formation of the ova
  121. The daughter cells of this meiotic divisions have the same amount of genetic materials but not equal amounts of cytoplasm
  122. the primary oocyte is derived from the
  123. the product of the first meiotic division in the oogenesis
    secondary oocyte
  124. the secondary oocyte will divide again unequally which will produce an
    ootid (secondary polar body)
  125. chromosomes are made up of
    long fibers of chromatin which consist of DNA and associated proteins called histones
  126. mendels postulates were accepted as the basis for the study of
    transmission genetics
  127. transmission genetics
    how genes are transmitted from parents to offspring
  128. traits
  129. monohybrid cross
    cross that involves the contrasting between one pair of traits
  130. how is a monohybrid cross made
    by mating true breeding individuals exhibiting one of two contrasting charactersitics
  131. selfing
    the self fertilization of individuals from the first filial generation
  132. The first generation with true breeding parents will give rise to an all dominant trait offspring
  133. F2 monohybrid ratio
    • 3:1
    • 3/4 dom 1/4 rec
  134. reciprocal crosses
  135. due to reciprocal crosses, mendel determined that monohybrid crosses were
    not sex dependent
  136. mendels 3 postulates
    • unit factors in pairs
    • dominance and recessive
    • segregation
  137. unit factors in pairs
    genetic characters are controlled by unit factors existing in pairs in individual organisms
  138. function of unit factors for each trait
    factors serve as the basic unit of heredity and are passed unchanged from gen to gen which determine the traits expressed by each plant
  139. dominance and recessive
    when two unlike unit factors are responsible for a character, one factor is more dominant over the other
  140. segregation
    during gamete formation, unit factors separate randomly and equally in different cells
  141. example of segregation
    gametes of tall plants all receive one tall unit factor and vice versa of short plants
  142. random fertilization of the F1 generation will result in
    3/4 dom 1/4 rec
  143. phenotype
    physical expression of a trait
  144. unit factors represent units of inheritance called
  145. genotype
    the genetic makeup on an individual trait
  146. to determine if tall plants produced in F2 gen are Dd or DD you must
    use a test cross
  147. how to perform a test cross
    the organism expression the dom phenotype but an unknown genotype is crossed with a known homozygous recessive individual
  148. mendels fourth postulate
    independent assortment
  149. ratio of dihybrid crosses
  150. product law
    2 independent events occur at the same time, the prob of 2 outcomes occuring in combo is equal to the product of their individual prob of occurance
  151. example of product law
    the prob of an F2 plant having yellow and round seeds is (3/4)(3/4) because 3/4 of all F2 plants should be yellow and 3/4 should be round
  152. indepedent assortment
    during gamete formation, segregating pairs of unit factors assort independently of each other
  153. in independent assortment, all possible combos of gametes should be formed in equal frequency
  154. mendels 9:3:3:1 dihybrid ratio
    ideal ratio based on probability events
  155. 3 Probability events of mendels dihybrid ideal ratio
    • segregation
    • independent assortment
    • random fertilization
  156. homozygous
    alleles for a trait are the same
  157. heterozygous
    alleles for a trait are different
  158. when two traits are being looked at:
    2 traits of true breeding parents give rise to F1, then selfing occurs, what does the F2 generation look like
    half will look the the parents the other half will look different
  159. in a dihybrid crossin the principle of indepedent assortment
    it predicts 4 different gametes will arise
  160. true breeding means the individual is homozygous dom/rec
  161. segregation of genes during gamete formation, maternal and paternal factors separate
  162. following independent segregation, each gamete will receive one member of each nonhomo X  independently
  163. 2^n
    number of possible gametes
  164. product law
    sum law
    • and
    • or
  165. one event depends on another, the likelihood of the desired outcome is
    conditional probabilty
  166. the idea that the genetic material
    in living organisms is contained in chromosomes
    chromosomal theory of inheritance
  167. 3 classifications that 2 chromosomes are homologous
    • same size, centromere locations
    • homologous X form pairs
    • contains identical linear order of gene loci
  168. independent assortment leads to genetic variation
  169. can
    be used to analyze cases where there are alternative ways to
    achieve a combination of events.
    binomial theorem
  170. binomial theorem formula
  171. 4 assumptions of mendels mono and dihybrid ratios hypothetical predictions
    • each allele is dom/rec
    • segregation is uninfluenced
    • independent assortment
    • fertilization is random
  172. 2 points to keep in mind when predicting or analyzing genetic outcomes
    • outcomes of independent assortment and fertilization are subject to random fluctuations
    • as the sample size increases, the average deviation expected decreases
  173. null hypothesis
    • hypothesis assumes
    • that there is no real difference between the measured
    • values (or ratio) and the predicted values (or ratio)
  174. depending on the results of null hypothesis analysis what two outcomes may either be
    • rejected
    • fail to be rejected
  175. discovered X
  176. stainable material in nuclei of cells
    also known as mitosen
  177. theodor and wife marcel boveri worked with roundworm and
    • observed he development of dispermic embryo in sea urchin
    • cell with abnormal X inheritance didn't develop normally
  178. following independent segregation of each pair of homologs in meiosis anaphase 1, each gamete receives
    one member of each nonhomo X indepedently
  179. why can eagels see further than we can
    their photoreceptors are more closely packed
  180. uses van der waals forces between a probe and an object to map a 3Dtopography of a cell
  181. detects the interference pattern of xrays entering crystal latic of a molecule
    x ray crystallography
  182. imaging provides structural info based on the magnetic properties of atomic nuclei
  183. absorption
    object blocks part of the light
  184. reflection
    the wave front of the light bounces off the surface
  185. refraction
    light bends when it hits a substance that changes its speed
  186. scattering
    small fraction of the light is scattered in all directions, when dimensions of object are close to WV of light
  187. molecules that absorb light and reemit energy as light with a long WV
  188. is the key property that enables a lens to magnify an image
  189. can use scattered light to detect microbial shapes smaller than the WV of light but can not be resolved
    dark field
  190. magnification requires refraction of light through a medium of high refractive index
  191. parallel light rays entering the lens emerge at angles so as to intersect each other at the
    focal point
  192. a plane containing the focal point of the lens
    focal plane
  193. magnification that doesn't increase in resolution
    empty magnification
  194. expansion of the detail from magnification is limited by
    interference of light waves converging at the focal point
  195. two wave fronts interact by amplitudes in and out of phase
  196. result of interference between 2 waves is a pattern of bright and darkness
  197. a disk containing a bright central peak surrounded by rings of light and dark
    airy disk
  198. the width of the airy disk and the limit to resolution detail depends on
    the WV of light and the quality of the lens
  199. interacts with an object and acquires info we can use to detect the object
    electromagnetic radiation
  200. WV of the radiation must be equal to or smaller than the size of the object if we were to resolve its shape
  201. a lens situated directly above an object or specimen that we wish to observe at high resolution
    objective lens
  202. the greater the aperture of the lens the better the resolution
  203. consists of one or more lenses that focus parallel light rays from the light source onto a small area of the slide
  204. a device to vary the diameter of the light column
  205. when the cell extends across several focal planes, different portions appear out of focus (too near or far)
  206. adds dark color specifically to cells but not to the external medium or surrounding tissues
    simple stain
  207. mordant
    binding agent
  208. carbolfuchsun specifically stains mycolic acids
    acid fast stain
  209. when samples are boiled with malachite green, the stain binds to the endospore
    spore stain
  210. particles are excluded by the thick polysaccharide capsule which appear clear against the dark background
    negative stain
  211. a tiny object who size is well below the WV can be detected by
    light scattering
  212. disadvantage of dark field
    is that any tiny particle can scatter light  and interfere with viewing the speciment
  213. this microscopy technique is useful for eukary cells that contain many intracellular compartments
    phase contrast
  214. enhances contrast by superimposing the image of the specimen on a second beam of light that generate interference fringes
    interference microscopy
  215. advantage of fluorescence microscopy
    detects only live organisms whose DNA is intact
  216. advantage of dark field
    extremely small microbes and thin extracellular structures can be detected
  217. disadvantage of phase
    less effective for smaller microbes and for organisms who cytoplasm has a low refractive index
  218. advantage of interference
    shape of cells can be defined clearly
  219. disadvantage of interference
    requires complex optical adjustments and less effective for those with low refractive index
  220. fluorescent molecule used to stain a specimen
  221. 4 things fluorescence can label
    • chemical affinity
    • antibodies
    • gene fusion
    • DNA hybridization
  222. genetic recombination can be used to create a hybrid gene expression a protein that generates fluorescence
    gene fusion
  223. a short sequence of dna attached to a fluorophore will hybridize to a specific sequence in the genome
    DNA hybridization
  224. microscopy in which both excitation and emitted light are focused together
    laser scanning confocal microscopy
  225. 3 ways a specimen is prepared to be viewed under an electron microscope
    • sprayed copper grid
    • flash frozen
    • embedded in polymer for thin sections
  226. the acquisition of projected images from different angles of a transparent specimen
  227. a microscopic structure that is interpreted incorrectly
  228. uses van der waals forces to observe cells in water solution
  229. by crystallography can only model the appearance of a molecule at atomic resolution
    molecular visualization