Chromosomal Mutations Quiz

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Questions and Answers

What is a gain-of-function mutation?

A mutation resulting in a protein with a stronger effect (correct)

A mutation that eliminates the function of a protein

A mutation leading to weakened protein activation

A mutation causing the protein to remain unchanged

What is a splice-site mutation?

A mutation that affects only RNA splicing

A mutation that occurs within an exon

A mutation that does not impact protein sequence

A change at the border of exon and intron (correct)

Which type of mutation can cause loss of exons or inclusion of introns?

Frameshift mutation - deletion (correct)

Frameshift mutation - insertion

Missense mutation

Nonsense mutation

What is the significance of mutations that are advantageous to organisms?

They contribute to the variability of organisms and evolution Signup and view all the answers

Which type of cell mutations are inherited by offspring?

Mutations in reproductive cells Signup and view all the answers

In which type of mutation do all cells in an organism have a changed genetic information?

Hereditary mutation Signup and view all the answers

What is the term used to describe a state where a cell or organism has one or more sets of chromosomes beyond the basic set?

Euploidy Signup and view all the answers

Which type of gene mutations involve changes in the nucleotide sequence in a fragment of DNA in one gene?

SNP Signup and view all the answers

What term is used to describe an abnormal number of chromosomes in a cell, often seen in cancer cells?

Heteroploidy Signup and view all the answers

What type of mutations are caused by physical, chemical, or biological factors?

Induced mutations Signup and view all the answers

What is the term for gene and chromosomal mutations that lead to the death of the embryo, fetus, or offspring soon after birth?

Lethal mutations Signup and view all the answers

What are marker chromosomes / extra structurally abnormal chromosomes (ESACs)?

Small, additional structures with unknown origin unlike other chromosomes Signup and view all the answers

What is the term for the failure of homologous chromosomes to properly separate during meiosis?

Nondisjunction Signup and view all the answers

'Mutation' is best defined as:

'Any change in the genetic material of a given organism' Signup and view all the answers

What is a key characteristic of Drosophila melanogaster that makes it convenient for genetic research?

High fertility rate Signup and view all the answers

What is a unique feature of the chromosomes in the cells of the salivary glands of Drosophila melanogaster larvae?

Polytene (giant) chromosomes Signup and view all the answers

What is the significance of gene mutations in Drosophila melanogaster with respect to genetic studies?

Their effects relate to many morphological features Signup and view all the answers

How are polytene (giant) chromosomes formed in Drosophila melanogaster?

Through DNA replication without mitosis Signup and view all the answers

Where are genes predominantly located on polytene (giant) chromosomes in Drosophila melanogaster?

In the dark bands Signup and view all the answers

What is a common feature of Omphalocele (exomphalos)?

Intestines, liver, and other organs outside the abdomen Signup and view all the answers

What happens when a specific gene is activated on a polytene chromosome in Drosophila melanogaster?

A loop (puff) forms for transcription Signup and view all the answers

Which condition is defined by the absence of testes from the scrotum?

Cryptorchidism Signup and view all the answers

What role does gene amplification play in the gene expression of Drosophila melanogaster?

Allows for multiple gene copies and high expression levels Signup and view all the answers

What does the term Palpebral fissure refer to?

Opening between the eyelids Signup and view all the answers

Why are polytene (giant) chromosomes considered advantageous for studying gene expression?

They permit visualization of active genes and transcription sites Signup and view all the answers

What is the main feature of Proboscis in teratology?

Blind-ended tube-like structure on the face Signup and view all the answers

Where is Sella turcica commonly found?

In the human skull Signup and view all the answers

What is a Spermatozoon?

Haploid male gamete cell Signup and view all the answers

Who provided a significant contribution to the chromosomal theory of heredity through experiments on Drosophila melanogaster?

Thomas Hunt Morgan Signup and view all the answers

Which of these conditions involves eyes not properly aligning when focusing on an object?

Eye misalignment with object focus Signup and view all the answers

Which type of inversion includes a centromere?

Pericentric inversion Signup and view all the answers

What is the structural rearrangement within a chromosome that leads to the formation of chromosomes with either two long or two short arms?

Isochromosome Signup and view all the answers

What is the structural aberration where a fragment of a chromosome is inserted into a different place of the same chromosome or another chromosome?

Inversion Signup and view all the answers

Which type of chromosome is usually formed as a result of translocation and contains two centromeres?

Dicentric chromosome Signup and view all the answers

In which condition is part of the short arm of chromosome 5 deleted?

Cri du chat syndrome Signup and view all the answers

What is formed as a result of two breaks in the distal sections of both arms of a chromosome followed by their connection?

Ring chromosome Signup and view all the answers

Which type of translocation results in a reciprocal exchange between the long arms of chromosomes 9 and 22?

Philadelphia translocation Signup and view all the answers

Which symptom is NOT associated with cri du chat syndrome?

Long fingers Signup and view all the answers

What chromosomal abnormality is typically associated with Turner syndrome?

45,X Signup and view all the answers

Which syndrome involves an individual having an extra X chromosome (47,XXX)?

Klinefelter syndrome Signup and view all the answers

What is the chromosomal karyotype typically seen in individuals with XYY syndrome?

47,XYY Signup and view all the answers

Which of the following syndromes is caused by an additional copy of chromosome 21?

Down syndrome Signup and view all the answers

Which syndrome is characterized by a female type silhouette, gynaecomastia, and atrophy of seminiferous tubules?

Klinefelter syndrome Signup and view all the answers

In which syndrome do individuals have an extra X chromosome resulting in a 47,XXX karyotype?

Klinefelter syndrome Signup and view all the answers

Individuals with which syndrome typically show a 45,X karyotype and suffer from primary amenorrhea and lack of menstruation?

Turner syndrome Signup and view all the answers

Which syndrome presents with normal phenotype but has an extra Y chromosome in males?

XYY syndrome Signup and view all the answers

A 47,XX,+21 karyotype is associated with which genetic disorder showing symptoms such as epicanthal fold and mental retardation?

Down syndrome Signup and view all the answers

What type of chromosomal defect results in Down syndrome?

Unbalanced Robertsonian translocation Signup and view all the answers

Which chromosomal abnormality involves the presence of an additional copy of a translocated chromosome or its fragment?

Duplication Signup and view all the answers

What type of chromosomal defect is observed in Turner syndrome?

Deletion Signup and view all the answers

In which chromosomal abnormality does the amount of genetic material not change but its location shifts within the genome?

Balanced Robertsonian translocation Signup and view all the answers

Which type of chromosomal defect results in an increased number of chromosomes, such as Klinefelter syndrome?

XYY syndrome Signup and view all the answers

Which type of chromosomal aberration involves the breakage and rearrangement of fragments between two chromosomes?

Translocation Signup and view all the answers

In humans, a reciprocal translocation occurs when the break and exchange of sections happen between which type of chromosomes?

Non-homologous chromosomes Signup and view all the answers

Which chromosomal abnormality involves the cross connection of products from breaks in acrocentric chromosomes resulting in the loss of the short arms and the connection of the long arms?

Robertsonian translocation Signup and view all the answers

Which syndrome is characterized by an additional X chromosome in females, leading to developmental delays and learning disabilities?

XXX syndrome Signup and view all the answers

In which syndrome does an individual have only one X chromosome, leading to short stature, lack of puberty development, and infertility in females?

Turner syndrome Signup and view all the answers

What medical condition is characterized by the absence of one X chromosome in females, leading to short stature and infertility?

XXX syndrome Signup and view all the answers

Which genetic disorder is characterized by an extra X chromosome in males, resulting in tall stature and behavioral problems?

Klinefelter syndrome Signup and view all the answers

In which syndrome does an individual have an additional copy of chromosome 21, leading to characteristic facial features and intellectual disabilities?

Klinefelter syndrome Signup and view all the answers

What genetic condition results from males having an extra Y chromosome, leading to increased height and learning difficulties?

Turner syndrome Signup and view all the answers

Which genetic disorder involves females having a missing or incomplete X chromosome, leading to short stature and infertility?

Down syndrome Signup and view all the answers

Which numerical aberration is associated with the presence of an additional chromosome from a given pair?

Trisomy Signup and view all the answers

In which syndrome would you expect to find a karyotype of 47,XXY in males?

Klinefelter syndrome Signup and view all the answers

Which of the following is a condition that can result in a karyotype of 69,XXX and is associated with multiple developmental defects?

XXX syndrome Signup and view all the answers

Which type of chromosomal abnormality is typically associated with a female having only one X chromosome (45,X)?

Turner syndrome Signup and view all the answers

In which syndrome would you expect to find a male individual with a karyotype of 47,XYY?

XYY syndrome Signup and view all the answers

Which syndrome involves an individual having an extra Y chromosome (47,XYY)?

Klinefelter syndrome Signup and view all the answers

Which syndrome is characterized by the presence of an additional X chromosome in females (47,XXX)?

Turner syndrome Signup and view all the answers

In which syndrome does an individual have an extra copy of chromosome 21?

Down syndrome Signup and view all the answers

Which syndrome is characterized by the absence of one X chromosome in females?

Down syndrome Signup and view all the answers

Individuals with Klinefelter syndrome have an additional chromosome. What is the karyotype for Klinefelter syndrome?

47,XXY Signup and view all the answers

Which syndrome is characterized by individuals having a single X chromosome (45,X)?

Turner syndrome Signup and view all the answers

Study Notes

Genetic Abnormalities and Mutations

Euploidy/Polyploidy: a state where a cell or organism has one or more than one set of chromosomes beyond the basic set, e.g. triploidy (3 sets), tetraploidy (4 sets).
Gene mutations: changes in the nucleotide sequence of a DNA fragment in one gene, including:
- Single nucleotide polymorphism (SNP)
- Transition or transversion (substitutions)
- Insertion or deletion
- Leading to the creation of a new quality of the gene/allele
Heteroploidy: an abnormal number of chromosomes in a cell, resulting from irregular mitosis, often in cancer cells.
Induced mutations: caused by various mutagens, such as physical, chemical, or biological factors.

Chromosomal Aberrations

Meiotic/mitotic nondisjunction: the failure of homologous chromosomes (during meiosis) or sister chromatids (during mitosis) to properly separate during cell division, resulting in their uneven segregation for daughter cells.
Numerical aberrations:
- Aneuploidy: a change in the number of chromosomes from a given pair, including:
  - Nullisomy: lack of chromosomes from a given pair (2n-2)
  - Monosomy: lack of one chromosome from a given pair (2n-1)
  - Trisomy: an additional chromosome from a given pair (2n+1)
  - Tetrasomy: two additional chromosomes from a given pair (2n+2)
- Euploidy/Polyploidy: the presence of more than two complete haploid sets of chromosomes, e.g. triploidy (3n), tetraploidy (4n)
Structural aberrations:
- Deletion: loss of a chromosome segment
- Duplication: doubling of a specific segment of a chromosome
- Inversion: occurs as a result of breaks in two places of a chromosome, with the separated parts reversed and re-incorporated
- Translocation: breaking of chromosomes and rearrangement of fragments between two chromosomes, including:
  - Reciprocal translocation
  - Robertsonian translocation

Specific Genetic Disorders

Cri du chat syndrome: caused by the deletion of part of the short arm of chromosome 5, resulting in:
- Low birth weight and delayed growth
- Hypotonia
- Microcephaly
- Unusual facial features
- Intellectual disability
Down syndrome: caused by trisomy 21, resulting in:
- Epicanthal fold
- Large fissured tongue
- Brushfield spots on the iris
- Hypotonia
- Mental retardation
Turner syndrome: caused by 45,X, resulting in:
- Short stature
- Rudimentary ovaries
- Poorly developed nipples
- Underdevelopment of secondary sexual characteristics
- Primary amenorrhea
Klinefelter syndrome: caused by 47,XXY, resulting in:
- Female type silhouette
- Gynaecomastia
- Testicular dysgenesis
- Atrophy of seminiferous tubules

Other Key Concepts

Thomas Hunt Morgan's chromosomal theory of heredity: proved that genes are located on chromosomes
Drosophila melanogaster: a convenient experimental organism for genetic research, characterized by:
- Short development time
- High fertility
- Low maintenance costs
- Presence of polytene (giant) chromosomes
Polytene chromosomes: oversized chromosomes that develop from standard chromosomes, found in the salivary glands of Diptera larvae
Gene amplification: the process of multiple copies of genes permitting a high level of gene expression
Puffs: representing active genes, formed by the unfolding of chromatid fibers in each chromomere of the corresponding chromosome band

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Test your knowledge on different types of chromosomal mutations such as pericentric inversion, paracentric inversion, insertion, ring chromosome, and dicentric chromosome. Identify the characteristics and implications of each mutation.