Flashcards in MCM Correlation boxes- Quiz 2 Deck (45):
a deoxyribonucleotide is the building block for DNA. This structure consists of 2-deoxyribose with ___ attached at the 1' position and ___ is attached at the 5' position of the sugar?
Nucleoside analogs that lack a 3' OH group can inhibit DNA replication. These nucleosides only need be converted to dNTPs before they actively inhibit which replicative enzyme
what are the 3 nucleoside analogs that inhibit DNA replication?
the drug ara-C contains a sugar arabinose and is converted by animal cells into ara-CTP which deactivates DNA polymerase by what kind of inhibition? What disease is this drug used to treat?
this drug is taken up by HIV infected cells and gets utilized by viral reverse transcriptase
if an allele in the ___ gene is mutated, then individuals have an increased susceptibility to hereditary nonpolyposis colorectal cancer
MER complex (MSH2 or MLH1)
defects in DNA repair process cause some to suffer from a condition involving extreme sun sensitivity and are prone to melanoma and carcinomas because of thymine dimers. what disease is this?
In this rare autosomal disorder, genes that normally code for transcription coupled repair (TCR) in DNA are mutated. DNA cannot be repaired so cell dysfunction or death may occur. symptoms include neurological delay, photosensitivity, premature aging. Death normally occurs in the first 2 decades of life.
most commonly, cockayne syndrome involves a mutation in the __ gene which normally is involved in transcription coupled repair (TCR)
What is the tumor suppressor gene that, when mutated, increases the chance of developing breast or ovarian cancer 5 fold? (also associated with cervical, uterine, pancreatic, colon, pancreatic, testicular, and prostate cancer in men)
BRCA1 and BRCA2
Transcription factors are able to bind specific regions of DNA to regulate transcription of a certain gene. The area of the genome where they bind is called what?
Response elements are where transcription factors bind to DNA. Where are response elements found within the genome?
in the promoter or regulatory (enhancer) region of a gene
what kind of DNA modification do transcription factors usually use to regulate gene expression
a significant fraction of oncogenes are activated by aberrant increase in expression due to the activity of these regulatory factors
Name this gene: encodes a protein important for neurologic function, normally contains 30 CGG repeats but can contain over 200 copies upstream of the coding region if mutated (this mutation causes methylation of cytosine and then transcription is turned off and these poor kiddos have neuro issues)
FMR1 gene (fragile X mental retardation)
mot abundant structural protein in vertebrates
some lysines in pro collagen are post translationally modified in the cell to generate 5-hydroxylysines which are further modified how?
once outside the cell the lysine residues in collagen are oxidatively deaminated to what functional group
what kind of modification is essential to proper assembly and cross linking of collagen helices
hydroxylation of lysine and proline
mutations in lysyl hydroxylases result in skin, bone, and joint disorders because we cannot properly form what protein
what coenzyme is essential for activity of lysyl and propyl hydroxylases which function to activate collagen?
ascorbic acid (vitC)
what kind of disorder arises from defects in assembly of the core oligosaccharide or in processing complex types of glycoproteins in the golgi? (70% of these cases arise from a defect in the enzyme that makes mannose 1 phosphate)
congenital disorders of glycosylation
this method of determining number and gross structure of metaphase chromosomes however it does not provide information at the molecular level
what are the four types of chromosomal mutations?
translocation (2 chromosomes exchange segments of DNA- can be balanced or unbalanced meaning the two chromosomes end up dissimilar in length to their normal counterpart)
what is a bivalent?
a structure that forms during meiosis I which includes a duplicated pair of homologous chromosomes (4 chromatids corresponding to each chromosome)
what process is made possible because of the pairing of chromosomes in a bivalent? What occurs as a result of this process?
homologous recombination, genetic variation
Does any DNA synthesis occur between Meiosis I and Meiosis II?
the 4 gametes produced after Meiosis II is complete each contain what amount of DNA?
a phenomenon where an individual receives 2 copies of a chromosome (or part of a chromosome) from one parent and no copies from the other parent. Usually presents with no symptoms but can involve delayed development or mental retardation
uniparental disomy (usually occurs as random error)
what is the most well known syndrome caused by a uniparental disomy (UPD) which causes the affected individual to eat uncontrollably often leading to obesity
prader willi syndrome
what condition occurs when cells from one individual (who developed from one fertilized egg) have different genotypes? What causes this condition?
error in cell division early in embryonic life
what condition results from trisomy 21
what condition results from an individual who has some cells that are 46XY and some which are 47XXY?
resting mammalian cells in the G1 phase have how much DNA (if N refers to the amount in one haploid genome)?
mammalian cells in the G2 phase have how much DNA (if N refers to the amount in one haploid genome)?
mammalian cells in the M phase have how much DNA (if N refers to the amount in one haploid genome)?
4N until cytokinesis
what is the term describing cells in the human body which remain in G0 phase and thus cannot be regenerated? Give examples of this type of cell
cardiac muscle, neuron, RBC
what is the term describing cells in the human body which retain the ability to exit G0 and enter G1 phase when growth factors are present? Give examples of this type of cell
hepatocyte, epithelial, kidney tubules
what is the term describing cells in the human body which never enter the G0 phase and thus are constantly regenerated? Give examples of this type of cell
gut epithelium, skin, hair, bone marrow
what is the major mechanism used to terminate the activity of specific cyclin CDK complexes?
aging somatic cells in culture stop dividing after 30-50 passages in a process known as what? What causes this phenomenon to occur?
replicative senescence, telomere shortening
what is a feature of many somatic cells which preserves the length of telomeres to prevent replicative sentence?
RAS is known to be mutated in many variations of cancer. What is bound to RAS in its active state? What enzyme is responsible for activating RAS?
GTP bound, GEF activates by exchanging a GDP for GTP
RAS is known to be mutated in many variations of cancer. What is bound to RAS in its INACTIVE state? What enzyme is responsible for this inactivation of RAS?
GDP bound, GAP stimulates GTP hydrolysis to inactivate RAS