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GRE Chromosomal And Molecular Basis Of Inheritance

Subjects : gre, science, biology
Instructions:
  • Answer 50 questions in 15 minutes.
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  • Match each statement with the correct term.
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This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. A molecule that binds unpaired DNA strands - after its been separated by helicase - and stabilizes them until they serve as templates for the synthesis of new complementary strands.






2. A type of change in chromosome structure as a result of some sort of chromosomal breakage. Occurs when a chromosomal fragment repeats a segment. In some cases - if meiosis is in progress - a deleted fragment may become as an extra segment to a sister






3. A result of nondisjuction of sex chromosomes. Females are healthy and cannot be distinguished phenotypically from other females.






4. An enzyme that joins the sugar-phosphate backbones of the Okazaki fragments - forming a single new DNA strand.






5. An ordered list of the genetic loci along a particular chromosome.






6. A chromosome is missing in a aneuploid cell.






7. A result of nondisjuction of sex chromosomes.






8. In this - all four strands of DNA following replication have a mixture of old and new DNA. Proved incorrect and support came out for the semiconservative model.






9. The short initial nucleotide chain put in place before DNA polymerase begins synthesizing in the 5' to 3' direction. May consist of either DNA or RNA. In initiating the replication of cellular DNA - the primer is a short stretch of RNA with an availa






10. A type of change in chromosome structure as a result of some sort of chromosomal breakage. Occurs when a chromosomal fragment breaks and joins a nonhomologous chromosome.






11. The mammalian system for determining sex. The sex of the offspring depends on whether the sperm cell contains an X chromosome or a Y.






12. A genetic map based on recombination frequencies.






13. Predicted by Watson and Crick. Suggests that when a double helix replicates - each of the two daughter molecules will have one old strand - derived from the parent molecule - and one newly made strand.






14. The new strand of DNA moving in the direction away from the replication fork. Synthesized as a series of segments in contrast to the leading strand that elongates continuously.






15. The most common type of translocation. A type of change in chromosome structure as a result of some sort of chromosomal breakage. In this - nonhomologous chromosome exchange fragments.






16. A result of nondisjuction of sex chromosomes. In this case - it is the result of an extra X chromosome in a male - producting XXY. People have male sex organs - but the testes are abnormally small and the man is sterile. Some breast enlargement and o






17. Disorder caused by structurally altered chromosomes - specifically a deletion in chromosome 5. A child born with this deletion is mentally retarded - has a small head with unusual facial features - and has a cry that sounds like the mewing of a cat.






18. An abnormal number of a particular chromosome. A condition that arises when an aberrant gamete (a result of nondisjunction) unites with a normal one at fertilization.






19. DNA repair that involves cleaving by nuclease and gap refilling by DNA polymerase and ligase.






20. Each nucleotide added to a growing DNA strand is a nucleoside triphosphate - which is a sugar and a base with three phosphate groups. The triphosphate monomers used are chemically reactive - partly because their triphosphate tails have an unstable cl






21. Offspring that have new combinations of their parent'S phenotypes. When 50% of offspring are recombinants - geneticists say that there is a 50% frequency of recombination and is observed for any two genes that are located on different chromosomes.






22. An enzyme that catalyzes elongation of new DNA at a replication fork. As individual nucleotides align with complementary nucleotides along a template strand of DNA - DNA polymerase adds them to the growing end of the new DNA strand one by one.






23. A change in genotype and phenotype due to the assimilation of external DNA by a cell.






24. A result of nondisjuction of sex chromosomes. Do not exhibit any well-defined syndrome but tend to be somewhat taller than average.






25. The sex-determining region of Y. The gene on the Y chromosome required for the development of testes. In the absence of SRY - the gonads develop into ovaries. SRY is simply the trigger and other genes on the Y chromosome are required for normal testi






26. A method that maps chromosomes and locates genes with respect to chromosomal features - such as stained bands - that can be seen in the microscope. Ultimately show the physical distances between gene loci in DNA nucleotides.






27. One of the first imprinted genes to be identified. Although this growth factor is required for normal prenatal growth - only the paternal allele is expressed.






28. Helps relieve strain from the DNA double helix when helicase untwists it at the replication forks - causing tighter twisting ahead of the forks.






29. The strand of DNA that is added on to the template strand one at a time as the fork progresses--with the DNA polymerase nestled in the replication fork. Moves in the 5' to 3' direction.






30. A type of change in chromosome structure as a result of some sort of chromosomal breakage. Occurs when a chromosomal fragment lacking a centromere is lost. The affected chromosome is then missing certain genes.






31. Occurs when a mismatched nucleotide evades proofreading by DNA polymerase or arise after DNA synthesis is completed.






32. An enzyme that can start an RNA chain from scratch. Joins RNA nucleotides together one at a time - making a primer complimentary to the template strand at the location where initiation of the new DNA strand will occur.






33. A compact object that is the inactive X in each cell of a female. Although female mammals inherit two X chromosomes - one becomes almost completely inactivated during embryonic development and lies along the inside of the nuclear envelope. Most genes






34. Genes located on the same chromosome that tend to be inherited together in genetic crosses. These results deviate from those expected from Mendel'S law of independent assortment.






35. Helps in repairing and proofreading DNA. An enzyme that cuts out a segment of the strand of DNA containing damage - creating a gap which is filled in with nucleotides properly paired with the nucleotides in the undamaged strand by DNA polymerase and






36. Phenotypically female but are sterile because their sex organs do not mature. When provided with estrogen replacement therapy - girls with Turners develop secondary sex characteristics.






37. The process that accounts for the recombination of linked genes. Occurs while replicated homologous chromosomes are pair during prophase of meiosis I - one maternal chromatid and one paternal chromatid break at corresponding points and then are rejoi






38. Traits that are alternatives to the wild type because they are due to alleles assumed to have arisen as changes - or mutations - in the wild-type allele.






39. A cancer implicated by chromosomal translocations. The exchange of a larger portion of chromosome 22 with a small fragment from a tip of chromosome 9 produces a much shorted - easily recognized chromosome 22 - called the Philadelphia chromosome. Affe






40. A occasional mishap that may occur during meiosis in which the members of a pair of chromosomes do not move apart properly during meiosis I or sister chromatids fail to separate during meiosis II.






41. An aneuploid condition. Usually the result of an extra chromosome 21 so that each body cell has a total of 47 chromosomes. Also termed trisomy 21. Includes characteristic facial feature - short stature - heart defects - susceptibility to respiratory






42. A chromosome is present in triplicate in an aneuploid cell.






43. A way of expressing distances between genes - defining one map unit as equivalent to a 1% recombination frequency.






44. A gene located on either sex chromosome. In humans - the term has historically referred specifically to a gene on the X chromosome so fathers pass sex-linked alleles to all of their daughters and none of their sons while mothers can pass sex-linked a






45. According to this theory - Mendelian genes have specific loci (positions) on chromosomes - and it is the chromosomes that undergo segregation and independent assortment.






46. An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells - thus restoring their original length and compensating for the shortening that occurs during DNA replication. Made possible by the presence in the telomerase of a short






47. A sex-linked recessive disorder. Defined by the absence of one or more of the proteins required for blood clotting. When injured - people with this disease have prolonged bleeding because a firm clot is slow to form. Patients receive intravenous inje






48. The system for determining sex in grasshoppers - cockroaches - and some other insects. In these insects - there is only one type of chromosome - the X. Females are XX and males are XO. Sex of the offspring is determined by whether the sperm cell cont






49. Adenine doubles bonds thymine and guanine triple bonds cytosine.






50. Nucleotide sequences found in eukaryotic chromosomal DNA that make up for the fact that DNA polymerases cannot replicate the ends of DNA strands since there is no 3' end there. Do not contain genes but rather the DNA has multiple repetitions of one s