Module 4: Specialized Topics

Question 1

3 Postulates of Differential Gene Expression:

1. Every cell nucleus contains the _____ established in the fertilized egg. In molecular terms, the DNAs of all differentiated cells are ____.
2. The unused genes in differentiated cells are _____, and they retain the potential for being expressed.
3. Only a ____ percentage of the genome is expressed in each cell, and a portion of the RNA synthesized in the cell is ____ for that cell type.

Answer 1

1. complete genome; identical
2. NOT destroyed or mutated
3. small; specific

Question 2

It is the process by which an individual cell acquires a specialized function. It requires a change in the pattern of gene expression in a cell.

Answer 2

Differentiation

Question 3

_____ give rise to all the connective tissues of the body.

Answer 3

Mesenchymal Stem Cells

Question 4

_____ combines the chromosomes of the male and female parent.
A ____ contains the combined genomes of the parents.

Answer 4

Fertilization
Zygote

Question 5

True or False

Each cell in the body of the organism that develops from that zygote has exactly the same genome. But different sets of genes are active (turned ON) in different types of cells.

Answer 5

True

Question 6

____ is the complete set of genes or genetic material present in a cell or organism.

Answer 6

Genome

Question 7

____ refers to the selective increase in the number of copies of a gene coding for a specific protein without a proportional increase in other genes. It is the multiple replications (repeated copying) of a section of the genome.

Answer 7

Gene Amplification

Question 8

Proofs of Gene Amplification (3)

Answer 8

1. Polytene Chromosomes
2. Lampbrush Chromosomes
3. Reticulcytes

Question 9

_____ are found in the salivary gland cells of the fruit fly Drosophila; ~2000 μm in length.

Answer 9

Polytene Chromosomes

Question 10

_____ occur in the oocytes (germ cells in the ovary) of amphibians and in some insects; extremely large synapsed homologous chromosomes which can be seen in the diplotene stage of meiotic prophase I; ~1500 to 2000 μm in length.

Answer 10

Lampbrush Chromosomes

Question 11

_____ occur in immature red blood cells.

Answer 11

Reticulocytes

Question 12

Polytene chromosomes in Drosophila are produced by ______, a process that occurs in cells of the larval salivary glands of many Dipteran species. These cells do not undergo mitosis, and they grow by expanding to about 150 times their original volume.

Answer 12

Endoreplication

Question 13

Polytene chromosomes are formed by the fusion of ____ of all the 8 chromosomes found in the cell.

Answer 13

Centromeres