Question 1

________ is the process of cell or tissue change in development.
A)Transformation
B)Morphogenesis
C)Development
D)Change
E)None of these

Accepted Answer

Morphogenesis refers to the process of cell or tissue change in development. Transformation may also refer to changes in cells, but it typically refers to a change in their genetic composition. Development is a broader term that encompasses all stages of growth and maturation. Change is too general to accurately describe the specific process being referred to.

Question 2

The developmental fate of a cell is established by the process termed
A)development.
B)differentiation.
C)determination.
D)specialization.
E)A,B,and C only

Accepted Answer

The process which establishes the developmental fate of a cell is called determination. Differentiation refers to the process by which the cell develops specific structures and functions, while specialization refers to the specific functions performed by a mature cell type. Therefore, option C is the best choice as it refers to the specific process of determination. Option A and B are not precise enough as they do not specifically refer to the establishment of cell fate. Option D is also not the best choice as it does not refer to the process but rather the outcome of the process.

Question 3

Mammalian sex determination is controlled by
A)XIST.
B)SRY.
C)XIC.
D)All of these
E)None of these

Accepted Answer

A

Question 4

Antibody genes
A)contain both constant and variable regions.
B)are formed by cutting and splicing DNA in B cells during development.
C)are made from two heavy and two light chains,each of which has a variable region.
D)each recognize one antigen and are the only antibody made by their B cell.
E)All of these

Accepted Answer

Antibody genes contain both constant and variable regions, are formed by cutting and splicing DNA in B cells during development, are made from two heavy and two light chains, each of which has a variable region, and each recognize one antigen and are the only antibody made by their B cell.

Question 5

Which of the following cell types has the lowest developmental potential?
A)Oocyte
B)Red blood cell
C)Embryonic stem cell
D)Zygote
E)All have equal developmental potential.

Accepted Answer

Red blood cells have the lowest developmental potential because they are fully differentiated, lack a nucleus, and cannot divide or differentiate into other cell types.

Question 6

The X-inactive specific transcripts gene is designated
A)SRY.
B)XIC.
C)Xce.
D)MATa.
E)Xist.

Accepted Answer

The X-inactive specific transcripts gene is abbreviated as Xist. It is responsible for the inactivation of one of the X chromosomes in female mammals. The other options represent different genes or regions that are not directly related to X chromosome inactivation.

Question 7

The X-inactivation center gene is
A)SRY.
B)XIC.
C)Xce.
D)MATa.
E)Xist.

Accepted Answer

The X-inactivation center (XIC) is a region on the X chromosome that plays a crucial role in X chromosome inactivation, and Xist is a gene within this region that is essential for the process.

Question 8

The X-controlling element gene is
A)SRY.
B)XIC.
C)Xce.
D)MATa.
E)Xist.

Accepted Answer

The answer of The X-controlling element gene is
A)SRY.
B)XIC.
C)Xce.
D)MATa.
E)Xist....

Question 9

SRY is
A)a single-region Y gene.
B)a Y-inactivation center gene.
C)the sex-determining region of the Y chromosome.
D)a Y-controlling element.
E)None of these

Accepted Answer

SRY stands for sex-determining region of the Y chromosome and is responsible for initiating male sex determination during embryonic development. It is not a single-region gene, Y-inactivation center gene or Y-controlling element.

Question 10

Which of the following statements is true?
A)Sex determination in fruit flies depends on the X : autosome ratio.
B)Mammalian sex determination can be influenced by temperature.
C)Mammals experience random Y inactivation.
D)The testis-determining factor gene is X-linked.
E)Dosage compensation occurs in the same way in most animals.

Accepted Answer

In fruit flies (Drosophila), sex determination is based on the ratio of X chromosomes to autosomes. If the ratio is 1:1, the individual will develop as female, while a ratio of 1:2 results in male development.

B is incorrect because in mammals, sex determination is controlled by genetic factors on the sex chromosomes and is not influenced by temperature.

C is incorrect because in mammals, only one X chromosome in females is randomly inactivated (not the Y chromosome).

D is incorrect because the testis-determining factor (TDF) gene, responsible for male development in humans, is located on the Y chromosome and is not X-linked.

E is incorrect because the process of dosage compensation, which equalizes the expression of X-linked genes in females and males, varies between different animal species. For example, in mammals, dosage compensation is achieved through X inactivation, while in fruit flies, it is achieved through increased transcription of the single X chromosome in males.

Question 11

Which of the following correctly expresses the order of development?
A)Fertilization,development,maturity
B)Induction,determination,differentiation
C)Induction,differentiation,determination
D)Fertilization,differentiation,determination
E)None of these

Accepted Answer

The correct order of development is induction, determination, and differentiation. Induction is the process by which one cell population influences the development of another, determination is when a cell becomes committed to a specific fate, and differentiation is the process by which committed cells acquire their specific structures and functions.

Question 12

In Drosophila,sex determination is carried out by
A)a cascade of alternative splicing.
B)the SRY gene.
C)histone modification.
D)the DMRT1 gene.
E)All of these

Accepted Answer

In Drosophila, sex determination is carried out by a cascade of alternative splicing. This involves the regulation of the splicing of pre-mRNA transcripts which ultimately determines the sex of the fly.

Question 13

In the snail Limnaea peregra, shell coiling is determined by the nuclear alleles S (dextral) and s (sinistral). This gene is a maternal effect gene that influences egg formation, which in turn influences whether the snail that hatches from the egg has a shell that coils to the right (dextral) or left (sinistral). A female sinistral snail is mated with a sinistral male snail. The genotypes of both are unknown. All the F1 progeny are dextral. When the members of the F1 generation are crossed, they yield an F2 generation that is S1U1P13S1S1P0/S1U1B14S1U1B0 dextral and S1U1P11S1S1P0/S1U1B14S1U1B0 sinistral.
-What were the genotypes of the sinistral snails?
A)ss female and Ss male
B)Ss female and Ss male
C)SS female and ss male
D)Ss female and ss male
E)ss female and SS male

Accepted Answer

The answer of In the snail Limnaea peregra, shell coiling...

Question 14

In the snail Limnaea peregra, shell coiling is determined by the nuclear alleles S (dextral) and s (sinistral). This gene is a maternal effect gene that influences egg formation, which in turn influences whether the snail that hatches from the egg has a shell that coils to the right (dextral) or left (sinistral). A female sinistral snail is mated with a sinistral male snail. The genotypes of both are unknown. All the F1 progeny are dextral. When the members of the F1 generation are crossed, they yield an F2 generation that is S1U1P13S1S1P0/S1U1B14S1U1B0 dextral and S1U1P11S1S1P0/S1U1B14S1U1B0 sinistral.
-What was the genotype of the mother of the female snail?
A)SS
B)Ss
C)ss
D)Ss or ss
E)SS or Ss

Accepted Answer

Since all F1 progeny are dextral, the mother must have had the genotype that does not contribute the dextral allele (S), because shell coiling is determined by the maternal genotype. Given that the mother was sinistral and all F1 are dextral, the mother's genotype must have been ss, as the maternal effect gene's phenotype in the offspring is determined by the mother's genotype, not the offspring's own genotype.

Question 15

The best model organism for studying cell fate from fertilized egg through adult is
A)Arabidopsis thaliana.
B)Caenorhabditis elegans.
C)Drosophila melanogaster.
D)Mus musculus.
E)Saccharomyces cerevisiae.

Accepted Answer

Caenorhabditis elegans is widely recognized as an excellent model organism for studying cell fate and development from a fertilized egg to an adult due to its simple and well-characterized developmental lineage, transparent body, and relatively short life cycle.

Question 16

The central function of X-inactivation is
A)silencing imprinted genes.
B)enhancing the expression of genes on the chromosome left active.
C)dosage compensation.
D)silencing deleterious alleles.
E)None of these

Accepted Answer

The central function of X-inactivation is dosage compensation. This is achieved by inactivating one of the two X chromosomes in females, which ensures the levels of X-linked gene expression are similar to those in males who only have one X chromosome. This is essential for normal development and cellular function. Silencing imprinted genes, enhancing the expression of genes on the active chromosome, and silencing deleterious alleles are all possible consequences of X-inactivation but are not its central function.

Question 17

________ cells may differentiate into any cell or tissue type.
A)Pluripotent
B)Omnipotent
C)Totipotent
D)Hyperpotent
E)Potent

Accepted Answer

Totipotent cells have the ability to differentiate into any cell type, including the extraembryonic or placental cells. They are the most versatile cells and are found in the earliest stages of development, such as a fertilized egg.

Question 18

Homeobox genes
A)encode proteins with a conserved sequence of amino acids.
B)are important in development.
C)are conserved in multicellular animals.
D)are transcription factors.
E)All of these

Accepted Answer

Homeobox genes encode transcription factors with a conserved sequence of amino acids, and they are important in developmental processes in multicellular animals.

Question 19

Which of the following is not true of X-inactivation?
A)It is necessary for dosage compensation.
B)It is the cause of calico color in cats.
C)The mechanism includes transcription of the XIST gene and chromatin remodeling.
D)The XIST RNA is non-coding.
E)The master regulatory gene for X-inactivation is sxl or sex-lethal.

Accepted Answer

The master regulatory gene for X-inactivation in mammals is not sxl or sex-lethal, which is a gene involved in sex determination in Drosophila. In mammals, the master regulator of X inactivation is Xist. Therefore, choice E is not true of X-inactivation.

Question 20

T and B cells are so named for the types of antigens they attack.

Accepted Answer

The answer of T and B cells are so named...

Quiz 19: Genetic Analysis of Development

________ is the process of cell or tissue change in development.

The developmental fate of a cell is established by the process termed

Mammalian sex determination is controlled by

Antibody genes

Which of the following cell types has the lowest developmental potential?

The X-inactive specific transcripts gene is designated

The X-inactivation center gene is

The X-controlling element gene is

SRY is

Which of the following statements is true?

Which of the following correctly expresses the order of development?

In Drosophila,sex determination is carried out by

The best model organism for studying cell fate from fertilized egg through adult is

The central function of X-inactivation is

________ cells may differentiate into any cell or tissue type.

Homeobox genes

Which of the following is not true of X-inactivation?

T and B cells are so named for the types of antigens they attack.