Chapter 6

Question 1

What are eukaryotes descended from?

Answer 1

Prokaryotes

Question 2

The first eukaryote began as what type of organism?

Answer 2

Unicellular

Question 3

How did multicellularity start in eukaryotes?

Answer 3

First with formation of colonies, followed by cell specialization, then by simple symbiosis

Question 4

Why is yeast a model eukaryote to study?

Answer 4

Because of its relative simplicity, ease of growth, having both haploid and diploid states, and safety

Question 5

What are some properties of a yeast’s genome?

Answer 5

• Many yeast strains contain one o more plasmids
• genome is relatively compact
• genes account for 72% of genome
• few contain introns
• about 6000 protein-coding genes

Question 6

800 million years ago, the metazoa split into which 3 groups?

Answer 6

• fungi
• plants
• animals

Question 7

Higher plants evolved from which single-celled organism?

Answer 7

Green algae

Question 8

Which higher plant was the first to have its full genome sequenced?

Answer 8

Arabidopsis thaliana (related to turnip, cabbage, broccoli)

Question 9

What are some properties of Arabidopsis thaliana’s genome?

Answer 9

• small genome
• five chromosomes
• genome relatively compact
• rich in genes that encode water-transporting channels, peptide-hormone transporters, metabolic and biosynthetic enzymes, and proteins involved in defense, detoxification, and environmental sensing

Question 10

Plants have many special metabolic pathways for photosynthesis and for the metabolism of cell wall components like what?

Answer 10

• Alkaloids and growth regulators such as auxin and gibberellins
• light sensors that regulate development and circadian responses

Question 11

What are some defense mechanisms plants have against for pathogens?

Answer 11

• production of reactive oxygen species
• defence molecules against animals
• produce molecules that attract pollinators or see-dispersal agents