DNA Repair Defects and Disease

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Which type of radiation is absorbed strongly by DNA and can cause damage?

X-rays

Gamma rays

UV-B rays

UV-C rays (correct)

Which enzyme is responsible for repairing mismatched bases during DNA replication?

Exonuclease

Oxygen radicals

Polymerase

MMR enzyme (correct)

How many genes participating in DNA repair were revealed by the recent publication of the human genome?

Less than 130

More than 130 (correct)

130

The number is unknown

Which mechanism of DNA repair involves the removal and replacement of damaged bases?

Excision repair Signup and view all the answers

Which enzyme is responsible for removing a specific kind of base damage in the Base Excision Repair (BER) process?

DNA glycosylase Signup and view all the answers

Which enzyme is responsible for synthesizing to fill in the gap in the Base Excision Repair (BER) process?

DNA Polymerase Signup and view all the answers

Which enzyme is responsible for removing Uracil in the Nucleotide Excision Repair (NER) process?

DNA glycosylase Signup and view all the answers

Which enzyme is responsible for filling in the correct nucleotides in the Nucleotide Excision Repair (NER) process?

DNA Polymerase Signup and view all the answers

Which proteins are involved in recognizing and repairing erroneous insertion, deletion, and mis-incorporation of bases in the Mismatch Repair (MMR) process?

MutS Signup and view all the answers

Which of the following is the main function of the proteasome?

To degrade unneeded or damaged proteins Signup and view all the answers

What is the significance of the 2004 Nobel Prize in Chemistry awarded to Aaron Ciechanover, Avram Hershko, and Irwin Rose?

Their research on the role of ubiquitin in proteolytic pathways Signup and view all the answers

What is the most common source of genetic variation between humans?

Single nucleotide polymorphisms (SNPs) Signup and view all the answers

What are polymorphisms?

Normal differences between people Signup and view all the answers

Which mechanism is used by the cell to repair a complete break in a DNA molecule?

Nonhomologous End-Joining (NHEJ) Signup and view all the answers

Which proteins are used in homologous recombination to repair double strand breaks?

BRCA1 and BRCA2 Signup and view all the answers

Which phase of the cell cycle does DNA replication occur?

S phase Signup and view all the answers

Which checkpoint in the cell cycle ensures that everything is ready to enter the M (mitosis) phase and divide?

G2 checkpoint Signup and view all the answers

function of BER enzymes

DNA glycosylase = remove damaged base AP endonuclease/ exonuclease = nick phosphate back bone/ remove nucleotide DNA polymerase beta = replace nucleotide DNA ligase = seals back bone Signup and view all the answers

function of enzymes in NER

TFIIH = recognition X products = create the bubble DNA polymerase delta and epsolin = fill in correct nucleotides DNA ligase = seals back bone Signup and view all the answers

Function of enzymes in MMR

<h1>MSH2 (MutS) = recognition MLH1 (MutL) = makes complex with MutS and MutH MutH = recognizes CH3-parental and makes nick on daughter strand</h1> Signup and view all the answers

Defect in MMR genes are associated with?

colon cancer Signup and view all the answers

BER, NER, and MMR are all apart of what repairing system?

Single-Strand Breaks (SSB) Signup and view all the answers

Direct joining can also be called

Nonhomologous end-joining (NHEJ) Signup and view all the answers

To fix a complete break in double strand breaks what two things can be done?

Direct joining and homologous recombination Signup and view all the answers

Cell cycle checkpoint protein

G1 checkpoint = cyclin D-cdk4 G1 checkpoint = P53-p21 G2 checkpoint = Cyclin B-cdK2 Mitotic checkpoint = P53-cdK2-GADD45 Signup and view all the answers

Twp apoptotic genes are?

BCL2 and TP53 Signup and view all the answers

What is the role of Ubiquitin-proteasome?

Degrade unneeded or damaged proteins Signup and view all the answers

Genetic alterations that occur in more than___ percent of the population are called polymorphisms.

1 Signup and view all the answers

Match associated cancers with mutation

Acute Lymphoblastic Leukemia = d9p Retinoblastoma = d13q14 CML = t(9;22) Burkitt's Lymphoma = t(8;14)(q24;q32) Signup and view all the answers

Components related to the particular trinucleotide repeat diseases.

Fragile X = 5' untranslated region of FMR1 <blockquote> 200 repeats of CGG = Fragile X Huntington's disease = HTT gene located on 4p16.3 40 of CAG = Huntington's disease </blockquote> Signup and view all the answers