BSCI 30050 Human Genetics Final Exam Study Guide Fall 2009 Chapter 13 Chromosomes Know the basics of the following chromosomal disorders o Deletions results in missing copies of genes caused by a break or unequal crossing over o Duplications results in extra copies of genes Caused by unequal crossing over or by mistakes in DNA replication o Translocations nonhomologous chromosomes exchange segments Type 1 Robertsonian translocation two nonhomologous chromosomes brak at the centromere and their long arms fuse The short arms are lost causes 5 of Down Syndrome chro 21 4 Type 2 Reciprocal Translocation two nonhomologous chromosomes exchange a portion of their chromosome arms Some people carry a translocation but are not missing any genetic material unless the breaking point interrupts a gene o Inversions flipped region of chromosome 5 10 cause health problems caused by disruption in genes Type 1 Paracentric region does not include the centromere results in 4 possibilities one normal chromatid one dicentric chromatid with the centromeres from each chromosome one inversion chromatid and one acentric chromatid with no centromere which will be unable to hook to spindle fibers Type 2 Pericentric region includes centromere One normal chromatid Two abnormal chromatids with duplicated regions One inversion chromatid What are isochromosomes chromosomes with identical arms forms when centromeres divide along the incorrect plain Results in a centromere with 2 short arms or a centromere with 2 long arms What are ring chromosomes chromosomes shaped like a ring Occurs in 1 25 000 conceptions Arises when telomeres are lost and the sticky part of the chromosomes fuse Phenotype associated with the loss or addition of genetic material What is uniparental disomy two copies of a chromosome from one parent and none from the other genomic imprinting 1 Chapter 18 Cancer What is cancer begins from a single abnormal cell that grows and divides Mutations allow the cell to undergo cell division which produces more abnormal cells How do germline and sporadic cancer differ o Somatic cells sporadic only affect the individual o Germline often inherited usually require second somatic mutation Are cancers caused by a single mutation or is more than one needed o Some need more than one mutation o Oncogenes cancer caused when they are activated without cause their job is to stimulate and regulate mitosis o Tumor suppressor genes deletion of inactivation causes cancer Affects cell cycle control their job is to inhibit mitosis What is the significance of telomerase telomerase is an enzyme that adds telomere sequences to the ends of the chromosomes Usually telomerase is turned off which limits cell division Cancer cells express telomerase which allows them to divide indefinitely Know the various characteristics of cancer cells that make them different from normal cells o Divide continually o Divide quickly o Heritable mutations o Transplantable o Dedifferentiated lose their specialized function o Different appearance o Lack contact inhibition o Induces angiogenesis o Increases mutation rate o Invasive o Metastasize What are the two ways that cancer cells can be derived during the process of stem cell differentiation o Activation of Stem Cells o Loss of Specialization dedifferentiation caused by chemical reversine o Too many stem cells o Uncontrolled tissue repair What is dedifferentiation a cell losing their specialized identity Loses their function and regress to pseudostem cells How can cancer result from too many stem cells 2 o Cells express their stemness and lose specialization the extra cells pile up and cause tumors In terms of cancer formation how do acute injuries differ from chronic injuries o Acute resting stem cells can become activated and divide to fill in the tissue o Chronic there is persistent activation of stem cells to renew the tissue can veer out of control fueling abnormal growths What are oncogenes these are the mutated forms of proto oncogenes These promote cell division o How are they related to proto oncogenes these are the normal version of oncogenes Know the various ways that oncogenes can be activated o Viruses o Moving a proto oncogene to a new location separate the coding region for regulatory regions o Moving a proto oncogene next to a highly transcribed gene erroneous transcription What are tumor suppressor genes o Supposed to inhibit cell division Cancer caused by loss og genes that inhibit cell division How many mutations are requires for retinoblastoma to develop o Two mutations are required one copy of each RB gene What is the significance of the p53 gene o It s a cell cycle protein in the check points determines if a cell has DNA damage and can induce apoptosis mutation of this gene causes more than 50 of cancers Know the various environmental causes of cancer o Virus Toxin Radiation Diet What is the possible significance of cruciferous vegetables o It s a chemopreventative Their antioxidants bind to free radicals and the free radicals become non functional How do newer cancer drugs target specific aspects of the biology of cancer o Stimulate cells to regain specialization o Inhibits telomerase o Induces apoptosis o Inhibits angiogenesis Chapter 19 Genetic Technologies Biotechnology use or alteration of cells or biological molecules This is possible because the genetic code is universal What does PCR stand for Polymerase chain reaction 3 o What does PCR do increases the amount of a DNA sequence in a tube Replicates the sequence millions of times o What are the four components needed for a PCR reaction and what do they do Knowing parts of a target DNA sequence to be amplified Two types of lab made single stranded short pieces of A large supply of the four types of DNA nucleotide building DNA primers blocks DNA polymerase Taq1 What is recombinant DNA amplifying DNA within cells often using sequences from other organisms Combines DNA from two sources gene cloning Creates a new combination of genetic material o What is a restriction enzyme and how does it work cut DNA at specific locations the scissors o What are sticky ends single stranded DNA s single stranded extensions the tape What kinds of vectors are used with recombinant DNA o Plasmid o Bacteriophage o Bacterial artificial chromosomes o Yeast artificial chromosomes What is a genomic library o Collections of recombinant DNA that contain pieces of the genome library What method is used to find specific DNA fragments within a