Quiz 2 Flashcards
T or F: In Karyotyping, 20 cells are analyzed which is enough to rule out mosaicism to an acceptable level.
TRUE
It is the condensed inactivated X chromosome of female cells where its condensation occurs during interphase.
Facultative Heterochromatin
This consists of simple repeats of nitrogenous bases found around the centromeres of all chromosomes and the distal end of the Y chromosome that is used for the regulation of crossing over or the exchange of genes from one sister chromatid to the other during cell division.
Constitutive Heterochromatin
T or F: The Giemsa stain specifically binds to phosphate groups of the DNA where there is high guanine-cytosine bonding.
False
T or F: This Reverse banding method is particularly helpful for staining the distal ends of chromosomes.
True
T or F: C-banding stains the facultative heterochromatin, which usually lies near the centromere, and NOR staining highlights the satellites and stalks of telocentric chromosomes.
False
T or F: Because prophase and prometaphase chromosomes are more extended than metaphase chromosomes, the number of bands observable for all chromosomes increases from about 300 to 450 to as many as 800. This allows the detection of less obvious abnormalities usually not seen with conventional banding.
True
T or F: Analysis of FISH specimens is done by phase contrast microscopy by a clinical laboratory specialist in cytogenetics where usually 30 prometaphase cells are scored for congenital problems.
False
T or F: Fluorescent in situ hybridization can be used to determine the possible cause of a child’s developmental disability, identify pathogens that grow well in laboratory conditions and do not infer evolutionary relationships.
False
T or F: The aim of Comparative genomic hybridization is to quickly and efficiently compare two genomic DNA samples arising from two sources, which are most often closely related, because it is suspected that they contain differences in terms of either gains or losses of either whole chromosomes or sub-chromosomal regions.
True
T or F: Comparative genomic hybridization can detect both balanced and unbalanced chromosomal abnormalities because both do not affect copy number, which is what is detected by CGH technologies.
False
T or F: Although many types of microarray exists, they can be generally classified as either traditional solid-phase array with spots attached to a surface or the alternative bead array using polycarbonate beads, each with a specific probe and a ratio of three or more dyes.
False
T or F: Understanding the structure and function of cells is fundamental to all of the biological sciences, including cytogenetics.
True
T or F: Inclusion bodies are inert, non-living structures which actively participate in the metabolic activities of the cell.
False
T or F: To collect cells with their chromosomes in this condensed state, they are exposed to a mitotic inhibitor which blocks formation of the spindle and arrests cell division at the prometaphase stage.
False
T or F: Normally, chromosomes cannot be seen with a light microscope but during cell division, they become condensed enough to be easily analyzed at 1000 times.
True
T or F: Chromosomes are a key part of the process that ensures DNA is accurately copied and distributed in the vast majority of cell divisions.
True
T or F: Euchromatin is most abundant in cells that are less active in the transcription of many of their genes that contains silenced or methylated genes with high G-C content.
False
T or F: Satellite bodies vary in size according to the position of the primary constriction.
False
T or F: Secondary constriction is often associated with the nucleolus during interphase and may take part in the reorganization of the nucleolus at the end of cell division.
True
T or F: Telocentric chromosomes frequently have secondary constrictions on the short arms that connect very small pieces of DNA called “stalks” or “satellites” to the centromere.
False
T or F: Human chromosomes 13,15, 21 and 22 are acrocentric.
True
They are chromosomes that have the centromere slightly offset from the center leading to a slight asymmetry in the length of the two arms.
Sub-metacentric chromosomes
They are chromosomes where the centromere is found at the very end of the chromosome resulting to no p arm.
Telocentric chromosomes