64 Questions
What is the role of telomerase in the cell?
Repetitively adding the DNA sequence 5-TTAGGG-3 to rebuild telomeres
Where does the spindle apparatus attach during cell division?
Kinetochore
What is the function of centromeric heterochromatin in chromosomes?
Contains multiple clustered copies of genes for rRNA
What separates the sister chromatids to move to opposite poles of the dividing cell?
Mitotic spindle fibres
Where is the constriction visible on metaphase chromosomes where the sister chromatids are joined together?
Centromere
What structure in the cell contains active NORs that stain darkly with silver nitrate?
Centromeric heterochromatin
What is the role of telomerase in cell division?
Prevents the shortening of telomeres
Which structure is responsible for attaching spindle fibers to chromosomes during cell division?
Centromere
What happens when the telomeres become critically short in a cell?
Activation of DNA damage signaling
What is the main function of kinetochore during cell division?
Attachment of chromosomes to spindle fibers
Which component directly interacts with centromeric heterochromatin during mitosis?
Kinetochore
What is the function of telomerase?
It maintains the length of telomeres at the ends of chromosomes.
Which DNA sequences are classified as highly repetitive DNA?
Tandem Repetitive DNA
In which region of the chromosome is alpha satellite DNA predominantly located?
Centromere
What is the function of centromeric heterochromatin?
Attachment point for kinetochore proteins
Which structures are primarily responsible for separating sister chromatids during cell division?
Kinetochore proteins
What is the main role of mitotic spindle fibres during cell division?
Separation of sister chromatids
Why is G banding considered the preferred method for routine staining of chromosomes?
G banding is simple and slides can be kept for a long time without deterioration.
What are LINES and SINES in the context of chromosome composition?
LINES refer to Long Interspersed Elements, while SINES refer to Short Interspersed Elements.
G Banding is generally considered the preferred method for the routine staining of chromosomes due to its simplicity and the ability to keep slides for a long time without __________.
deterioration
Metaphase chromosomes are characterized by visible constrictions where sister chromatids are joined, known as the ______
constriction
In a karyogram, chromosomes are arranged in a specific order to provide a visual representation of an individual's entire set of chromosomes, also known as a chromosome ______
ideogram
The smaller arm of the chromosome is designated as being the '' arm and the long arm is the '' arm.
p
Match the chromosome landmarks with their descriptions:
Telomeres = Protective ends of the chromosome Centromeres = Region where spindle fibers attach during cell division Prominent bands = Clearly distinguishable parts of a chromosome by banding techniques Band = Darker or lighter segment of a chromosome distinguishable from adjacent parts
Match the following terms with their descriptions:
Acrocentric chromosomes = Have very small p arms and often have satellites (NOR region) on the end Telocentric chromosomes = Have the centromere at the end with no p arm (not present in the human karyotype)
Match the chromosome types with their distinguishing features:
Metacentric chromosomes = Have centromere in the middle creating two equal arms Submetacentric chromosomes = Have centromere slightly off-center creating a long arm (q) and a short arm (p) Acrocentric chromosomes = Have centromere close to one end creating a long arm and a very small p arm
Match the chromosome banding techniques with their descriptions:
G Banding = Staining method creating a unique pattern on chromosomes R Banding = Reverse of G Banding, highlighting different parts of chromosomes C Banding = Specifically stains centromeric heterochromatin regions Q Banding = Highlights specific regions related to telomeres
Match the chromosome staining techniques with their advantages:
G Banding = Preferred method for routine staining of chromosomes due to simplicity and long slide preservation Q Banding = Used for quality scoring in cytogenetics, higher resolution for specific microdeletion/duplication detection
Match the following chromosome terms with their definitions:
Karyogram = Arrangement of chromosomes based on centromere position, band pattern, and length NOR Satellite = Region with active nucleolar organizer regions staining darkly Satellite Stalks = Extension from centromeric region towards telomeres Chromosome Centromere Position = Determines the type of metacentric, sub-metacentric, or acrocentric structure
Match the following chromosome features with their descriptions:
G-Dark bands = Condense early in mitosis G-Light bands = Condense later in mitosis Replicate mid to late in S phase = Gene poor tissue specific genes Replicate early in S phase = Gene rich housekeeping genes
Match the following chromosome components with their functions:
Centromeric heterochromatin = Enriched in LINES (long interspersed elements) Telomeres = A-T rich DNA Kinetochore = Separating sister chromatids during cell division Spindle apparatus = Attaching spindle fibers to chromosomes during cell division
Match the following terms related to chromosome banding techniques with their meanings:
G Banding = Chromosome banding technique that involves staining chromosomes to create a pattern ISCN = Provides a universally understandable description of karyotypes and aberrations of chromosomes Quality score (bphs) = Used as a rating for banding resolution in cytogenetics FISH = Molecular cytogenetic technique used for region-specific assays
Match the following chromosome structures with their locations within the nucleus:
G-Banded chromosomes = Located in the interior of the nucleus Alpha satellite DNA = Localised at the nuclear periphery Active NORs = Contained within the nucleolus Gene rich housekeeping genes = Scattered throughout the nucleus
Match the following terms related to chromosome identification with their significance:
P and Q arms = Used for identifying different regions of a chromosome Ideograms = Visual representation of each chromosome at varying resolutions Chromosome banding patterns = Help in distinguishing different types of chromosomes based on structural features SINES and LINES = Classifications based on repetitive elements within chromosomes
Match the following chromosomal abnormalities with their corresponding descriptions:
Turner syndrome = Monosomy X Triploidy = 69 chromosomes Trisomy = Presence of an additional chromosome Diandry = Two paternal copies
Match the following statements with the correct chromosomal abnormality:
Not affected by maternal age = Triploidy Paternal X chromosome usually absent = Monosomy X Two maternal copies found in most cases = Diandry Failure to develop secondary sexual characteristics = Turner syndrome
Match the aneuploidy condition with its description:
Turner syndrome = Monosomy X Down syndrome = Trisomy 21 Patau syndrome = Trisomy 13 Klinefelter syndrome = Extra X chromosome in males
Match the type of nondisjunction with the resulting aneuploidy:
Meiosis I failure of homologous chromosomes to separate = Constitutional Aneuploidy Meiosis II failure of sister chromatids to separate = Monosomy X Mitotic errors post-zygotically = Mosaic Aneuploidy Maternal Age Effect = Increased risk of chromosome anomalies
Match the aneuploidy condition with its life expectancy:
Turner syndrome = Varies depending on associated health complications Down syndrome = Increased life expectancy compared to the past Patau syndrome = 90% mortality rate by 1 year, mean survival of 10 days Klinefelter syndrome = Close to normal life span with appropriate management
Match the following chromosomal abnormalities with their corresponding conditions:
Turner syndrome = 45,X Trisomy 21 = Down syndrome Trisomy 13 = Patau syndrome Trisomy 18 = Edwards syndrome
Match the following descriptions with the corresponding chromosomal alterations:
Robersonian Translocation = Special structural alteration changing the number of chromosomes Isochromosomes = Chromosomes with identical arms Derivative chromosomes = Chromosomes with altered genetic material due to rearrangements Combined structural abnormalities = Presence of both numerical and structural chromosomal anomalies
Triploidy results from 3 sets of haploid ______
gametes
An increase in maternal age is directly proportional to an increased risk of having a pregnancy affected by major __________
trisomies
Mitotic errors occur post zygotically and usually result in mosaic ______
aneuploidy
What is the difference between meiosis I and meiosis II nondisjunction?
Meiosis I nondisjunction is the failure of homologous chromosomes to separate, while meiosis II nondisjunction is the failure of sister chromatids to separate.
What is the relationship between maternal age and the risk of chromosome anomalies?
There is an increased risk of chromosome anomalies with advancing maternal age.
What is the relationship between maternal age and the risk of having a live born baby with Down syndrome?
The risk increases with advancing maternal age.
What is the difference between hypodiploid and hyperdiploid aneuploidies?
Hypodiploid has less than 46 chromosomes, while hyperdiploid has more than 46 chromosomes.
Explain the concept of Robertsonian Translocations and provide an example.
Robertsonian Translocations involve long arms of acrocentric chromosomes joining at the centromere. An example is rob(13;14).
What is the most common chromosomal anomaly in abnormal births?
Aneuploidy
What is the maternal age effect in relation to major trisomies?
An increase in maternal age correlates with an increased risk of major trisomies.
What is the difference between digyny and diandry in triploidy?
Diandry involves two paternal copies, while digyny involves two maternal copies.
What are the distinctive ultrasound features of both triploid phenotypes?
The distinctive ultrasound features are evidence of genomic imprinting.
What is the chromosomal abnormality associated with Turner syndrome?
Turner syndrome is associated with 45,X (Monosomy X).
What is the main function of telomerase in a cell?
Rebuilding telomeres by adding guanine-rich repetitive sequences
Explain the significance of chromosomal telomeres and the role of telomerase.
Chromosomal telomeres prevent DNA damage during replication, and telomerase rebuilds them to enable cell division.
How does telomerase contribute to preventing apoptosis in cells?
By rebuilding telomeres and preventing them from becoming too short.
What DNA sequence does telomerase repetitively add to chromosomal telomeres?
5-TTAGGG-3
What happens to cell division when telomeres become short?
Cells stop dividing and may undergo apoptosis.
What is chimerism and how does it occur?
Chimerism is a condition where an individual has two or more different sets of DNA in their body, usually occurring when two embryos fuse together to form a single individual.
Can you explain how a person with chimerism might have both male and female cells in their body?
If a female embryo fuses with a male embryo, the resulting individual could have both male and female cells in their body.
What are some physical characteristics that can result from chimerism?
Unique physical characteristics, such as different eye colors in each eye.
How does chimerism differ from other genetic conditions?
Chimerism is characterized by having two or more different sets of DNA in the body, often resulting from the fusion of two embryos.
What is the main cause of chimerism in individuals?
Chimerism usually occurs when two embryos fuse together to form a single individual.
This quiz covers fundamental concepts of cell division including telomerase, centromere, and mitotic spindle fibers. Test your knowledge on how chromosomes are rebuilt, how sister chromatids are joined, and how the spindle apparatus assists in cell division.
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