Chapter 1: Introduction to Genetics and Model Organisms

Question 1

What is a genome?

Answer 1

A genome is a complete set of genetic instructions for any organism; either RNA or DNA.

Question 2

How does the coding system vary among organisms?

Answer 2

Coding system for genomic information very similar among organisms.

Question 3

Define transmission genetics.

Answer 3

Field of genetics encompassing the basic principles of genetics and how traits are inherited

Question 4

Define molecular genetics.

Answer 4

Study of the chemical nature of genetic information and how it is encoded, replicated, and expressed

Question 5

Define population genetics.

Answer 5

Study of the genetic composition of populations (groups of members of the same species) and how their gene pools change with the passage of time

Question 6

What are model genetic organisms? What is their function?

Answer 6

• Organisms with characteristics that make them useful for genetic analysis.
• Used to transfer knowledge to more complicated organisms

Question 7

What are the four characteristics of model genetic organisms?

Answer 7

• Short generation time
• Production of numerous progeny for a relatively low price
• The ability to be reared in a laboratory environment
• They possess simply organized, fully sequenced genomes, which are either haploid or diploid.

Question 8

Provide examples of model genetic organisms.

Answer 8

• Drosophila melanogaster (fruit fly)
• Escherichia coli (bacterium)
• Caenorhabditis elegans (roundworm)
• Arabidopsis thaliana (thale cress plant)
• Mus musculus (house mouse)
• Saccharomyces cerevisiae (baker’s yeast)

Question 9

Why don’t we use wheat to study plants? What do we use instead?

Answer 9

• Wheat is too complicated

- Arabidopsis thaliana

Question 10

What was the name of the first living organism to be sequenced?

Answer 10

Bacteria behind meningitis and pneumonia

Question 11

When did the study of genetics arise?

Answer 11

Approximately 12,000 years ago, in which humans were cross-breeding animals and various plants

Question 12

Describe the Pangenesis concept.

Answer 12

• Greek, 520 BC
• Incorrect
• Genetic information from different parts of the body travels to the reproductive organs where it is transferred to the gametes

Question 13

Describe the Inheritance of Acquired Characteristics concept.

Answer 13

• Incorrect

- Acquired traits become incorporated into hereditary information

Question 14

What is the limitation of the acquired characteristics concept?

Answer 14

If you are amputated, your child would be amputated as well, as this is an acquired characteristic

Question 15

Describe the Preformationism concept.

Answer 15

• 1600
• Incorrect
• Miniature organism resides in sex cells, and all traits are inherited from one parent (homunculus)

Question 16

Describe the Blending Inheritance concept.

Answer 16

• Genes blend and mix

- Incorrect

Question 17

Describe the Germ-Plasm Theory.

Answer 17

• August Weismann, 1900
• Correct
• Germ-line tissue in the reproductive organs of males and females contain a complete set of genetic information that is transferred directly to the gametes
• All cells contain a complete set of genetic information

Question 18

Describe the Cell Theory concept.

Answer 18

• Correct

- All life is composed of cells, and cells only arise from cells

Question 19

Describe Mendelian inheritance.

Answer 19

• Correct

- Traits are inherited in accord with defined principles

Question 20

Who are the three most important modern day geneticists?

Answer 20

• Gregor Mendel (1866-1900)

- James Watson and Francis Crick (1953)

Question 21

What is a trait? What is it controlled by?

Answer 21

• A characteristic, which is either wanted or not

- Traits may be controlled by a single gene, or a set of genes

Question 22

What does a gene include as a transcription unit?

Answer 22

• Promoter
• RNA-coding region
• Terminator

Question 23

What are some of the implications of all organisms having similar genetic systems?
A) That all life forms are genetically related
B) That research findings on one organism’s gene function can often be applied to other organisms
C) That genes from one organism can often exist and thrive in another organism
D) All of the above

Answer 23

D) All of the above

Question 24

Would the horse make a good model genetic organism? Why or why not?

Answer 24

No, because horses are expensive to house, feed, and propagate; they have too few progeny, and their generation time is too long

Question 25

Match each description with the correct theory or concept.
A) Each reproductive cell contains a complete set of genetic information
B) All traits are inherited from one parent
C) Genetic information may be altered by the use of a characteristic
D) Cells of different tissues contain different genetic information

Answer 25

A) Germ-plasm theory
B) Preformationism
C) Inheritance of acquired characteristics
D) Pangenesis