Bio 392 Genetics | 132 Verified Questions And Answers
| Latest Study Solutions
Which type of chromosome has no p arms? ANS telocentric
What technique would you use to detect a target sequence in an intact chromosome using a labeled molecular
probe? ANS fluorescent in situ hybridization (FISH)
Which of the following is FALSE regarding organization in an interphase nucleus? ANS Each
chromosome occupies exactly the same region in all nuclei within an organism.
Karyotypes are a method for displaying chromosomes by grouping them into homologous pairs based on what
two distinguishing factors? ANS size and banding pattern
You are attempting to isolate cells for your karyotype, and you find one cell in each of the phases (prophase,
metaphase, anaphase, and telophase). Which one is best suited for a karyotype? ANS metaphase
Compare and contrast euchromatin to heterochromatin in the context of transcription. ANS Euchromatin-
1. Most expressed genes or genes that are actively transcribed are located here.
2. Condensation of the DNA in these regions is variable throughout the cell cycle.
Heterochromatin-
1. Chromatin is tightly condensed.
2. These regions contain fewer expressed genes or fewer genes that are actively transcribed.
What makes up the protein component of a nucleosome core? ANS Two tetramers of histone proteins
What is the first order of chromatin packing? ANS Coiling around nucleosomes
The second order of chromatin packing occurs when nucleosomes coil together to form a fiber that is 300 nm
in diameter. ANS False
, Which of the following is true of the gametes of a human female who has nondisjunction of her X
chromosomes in meiosis I? ANS The gametes contain 22 or 24 chromosomes.
If nondisjunction occurs in meiosis I of a mother, what proportion of her gametes could have been fertilized by
a normal sperm to produce a child with Turner syndrome? ANS 1/2
When nondisjunction occurs early in embryogenesis rather than gametogenesis, what would you expect in the
resulting karyotype? ANS mosaicism
Prader-Willi and Angelman syndromes are caused by which type of chromosomal mutations, both in
connection with chromosome 15? ANS uniparental disomy
During gametogenesis, what percentage of gametes would be aneuploid if the nondisjunction event occurred
during meiosis I? ANS 100% (4/4)
During gametogenesis, what percentage of gametes would be trisomic if the nondisjunction event occurred
during meiosis II? ANS 25% (1/4)
Why does aneuploidy in animals generally result in phenotypic abnormalities? ANS It results in an
imbalance of gene products from affected chromosomes, which alters normal development.
Which of the following consequences is a common outcome of a viable trisomy? ANS Reduced fertility
Which of the following accurately describes a possible meiotic nondisjunction event? ANS Homologs fail
to separate during meiosis I.
All of the following events occur during normal meiosis except _______. ANS two haploid gametes fuse
to form a diploid cell
In order to create the possibility of generating a trisomy, nondisjunction must occur during meiosis II. ANS
False
| Latest Study Solutions
Which type of chromosome has no p arms? ANS telocentric
What technique would you use to detect a target sequence in an intact chromosome using a labeled molecular
probe? ANS fluorescent in situ hybridization (FISH)
Which of the following is FALSE regarding organization in an interphase nucleus? ANS Each
chromosome occupies exactly the same region in all nuclei within an organism.
Karyotypes are a method for displaying chromosomes by grouping them into homologous pairs based on what
two distinguishing factors? ANS size and banding pattern
You are attempting to isolate cells for your karyotype, and you find one cell in each of the phases (prophase,
metaphase, anaphase, and telophase). Which one is best suited for a karyotype? ANS metaphase
Compare and contrast euchromatin to heterochromatin in the context of transcription. ANS Euchromatin-
1. Most expressed genes or genes that are actively transcribed are located here.
2. Condensation of the DNA in these regions is variable throughout the cell cycle.
Heterochromatin-
1. Chromatin is tightly condensed.
2. These regions contain fewer expressed genes or fewer genes that are actively transcribed.
What makes up the protein component of a nucleosome core? ANS Two tetramers of histone proteins
What is the first order of chromatin packing? ANS Coiling around nucleosomes
The second order of chromatin packing occurs when nucleosomes coil together to form a fiber that is 300 nm
in diameter. ANS False
, Which of the following is true of the gametes of a human female who has nondisjunction of her X
chromosomes in meiosis I? ANS The gametes contain 22 or 24 chromosomes.
If nondisjunction occurs in meiosis I of a mother, what proportion of her gametes could have been fertilized by
a normal sperm to produce a child with Turner syndrome? ANS 1/2
When nondisjunction occurs early in embryogenesis rather than gametogenesis, what would you expect in the
resulting karyotype? ANS mosaicism
Prader-Willi and Angelman syndromes are caused by which type of chromosomal mutations, both in
connection with chromosome 15? ANS uniparental disomy
During gametogenesis, what percentage of gametes would be aneuploid if the nondisjunction event occurred
during meiosis I? ANS 100% (4/4)
During gametogenesis, what percentage of gametes would be trisomic if the nondisjunction event occurred
during meiosis II? ANS 25% (1/4)
Why does aneuploidy in animals generally result in phenotypic abnormalities? ANS It results in an
imbalance of gene products from affected chromosomes, which alters normal development.
Which of the following consequences is a common outcome of a viable trisomy? ANS Reduced fertility
Which of the following accurately describes a possible meiotic nondisjunction event? ANS Homologs fail
to separate during meiosis I.
All of the following events occur during normal meiosis except _______. ANS two haploid gametes fuse
to form a diploid cell
In order to create the possibility of generating a trisomy, nondisjunction must occur during meiosis II. ANS
False
