Top Posters
Since Sunday
38
28
13
10
10
10
10
9
6
s
4
n
4
T
4
New Topic  
felipebelt felipebelt
wrote...
Posts: 316
3 years ago
Rhodobacter cells perform photosynthesis in the presence of light and grow heterotrophically in the dark. After being cultured in total darkness for multiple generations, phenotypic and genotypic changes occur. What phenotypic changes occur and what evolutionary processes are driving them?
Read 111 times
5 Replies
Replies
Answer verified by a subject expert
Fifagirl101Fifagirl101
wrote...
Posts: 209
3 years ago
Sign in or Sign up in seconds to unlock everything for free
 When a population of phototrophs is grown in the dark for multiple generations, the population will tend to lose the ability to produce photopigments and may even lose the ability to perform photosynthesis altogether. This occurs because there is no selection for the production of the pigments and enzymes necessary for photosynthesis. The production of photosynthetic pigments and enzymes is metabolically expensive, thus producing them when they are not needed results in a competitive disadvantage in the dark cultures, thus random mutants that produce fewer pigments take over Rhodobacter cultures grown in the dark. The evolutionary processes behind this phenotypic change are random mutations to the genome, followed by the selection of mutants that grow better in the dark.
This verified answer contains over 120 words.
1

Related Topics

wrote...
3 years ago
Thank you for helping me with my quiz
wrote...
3 years ago
Perfect
wrote...
3 months ago
Thx
wrote...
On Hiatus
2 months ago
thank you
New Topic      
Explore
Post your homework questions and get free online help from our incredible volunteers
  191 People Browsing
 396 Signed Up Today
Your Opinion
What's your favorite funny biology word?
Votes: 51

Related Images
 921
 2534
 135