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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. 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.






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






3. 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






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






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






6. 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.






7. Y-shaped region at the end of a replication bubble where the new strands of DNA are elongating.






8. 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.






9. 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






10. 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






11. Offspring that inherit a phenotype that matches one of the parental phenotypes.






12. A human sex-linked disorder. A disease characterized by progressive weakening of the muscles and loss of coordination. Affected individuals rarely live past their early 20s. A result of the absence of a key muscle protein called dystrophin.






13. The system for determining sex in most species of bees and ants. There are no sex chromosomes in these species - Females develop from fertilized ova and are thus diploid. Males - however - develop from unfertilized ova and are haploid; they have no f






14. The two alleles for each gene separate during gamete formation.






15. 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






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. Each nucleotide (monomer) consists of a hydrophobic nitrogenous base (T - A - C - or G) - the sugar dioxyribose - and a phosphate group. The phosphate of one nucleotide is attached to the sugar of the next - making up the 'backbone' of alternating ph






18. 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.






19. 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






20. The most common phenotype in a natural population.






21. 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.






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






23. 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.






24. The segments of the lagging strand that get added to the template strand. The segments get joined together by DNA ligase.






25. 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.






26. 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






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






28. 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.






29. The ___________ two genes are - the higher the probability that a crossover will occur between them and therefore the higher the recombination frequency. This process can occasionally break the physical connection between genes on the same chromosome






30. The system for determining sex in birds - some fishes - and some insects. The sex chromosome present in the ovum determines the sex of offspring. The sex chromosomes are designated Z and W. Females are ZW and males are ZZ.






31. 1. deletion 2. duplication 3. inversion 4. translocation






32. The general term for a chromosomal alteration in which an organism has more than two complete chromosome sets. There are more specific terms like triploidy (3n) and tetraploidy (4n) indicating 3 or 4 chromosomal sets - respectively.






33. 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






34. Can be distinguished from Watson and Crick'S semiconservative model in which the parent molecule somehow re-forms after the process of replication. Proved incorrect and support came out for the semiconservative model.






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






36. 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.






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






38. A type of change in chromosome structure as a result of some sort of chromosomal breakage. Occurs when a segment within a chromosome reverses.






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






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 enzyme that untwists the double helix at the replication forks - separating the two parental strands and making them available as template strands. This untwisting causes tighter twisting and strain ahead of the replication forks which is relieved






42. Or phages. Viruses that infect bacteria.






43. 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






44. 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






45. Traits that depend on which parent passed along the alleles for those traits. An exception to the display of Mendelian inheritance.






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






47. Genes located in organelles in the cytoplasm. Mitochondria and plastids contain small circular DNA molecules that carry genes coding for proteins and RNA and do not display Mendelian inheritance. For example - almost all the mitochondria come from th






48. The various proteins that participate in DNA replication actually form a single large complex since many of the protein-protein interactions actually facilitate the efficiency of the machine as a whole.


49. 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






50. Alleles of genes on nonhomologous chromosome assort independently during gamete formation.