It has been observed that when the sugar source changes in a growth medium, the growth rate of yeast vary widely in response. Some strains of yeast are slow to induce catabolic operons while other strains quickly synthesize proteins to process the new sugar. What might be one explanation for this difference in the growth rate of the strains?
A. Operons for anabolic pathways are controlled by many global regulatory mechanisms, and different sugars can favor initiation of different pathways depending on the strain of yeast.
B. Catabolic repression strategies of operons for using different sugars may vary among strains, thereby favoring initiation of transcription in one strain over another depending on the sugar.
C. All of the choices are correct.
D. Different sugars can act as effector or repressor molecules in various strains, promoting or inhibiting transcription of genes depending on the type of sugar present.
Answer: B
You might also like to view...
You would expect the bones of a growing child to have extremely active ____
a. osteoclasts b. fibroblasts c. osteoblasts d. adipocytes e. chondrocytes
Answer the question using the accompanying figure. According to the graph, which biome is defined as having the
highest overall mean annual precipitation?
a. savanna b. grassland c. tropical rainforest d. tundra e. desert
Answer the following statements true (T) or false (F)
1. The use of fossil fuels has increased the available resources for populations around the world, contributing to the exponential growth rate of the human population. 2. Developing countries are less likely to agree on a global climate change treaty because they might fear that it will slow their economic growth. 3. Population sizes of predators and their prey in a community are constant over time. 4. Pioneer species make up the climax community of a given ecosystem. 5. The main source of water in streams is replenished from groundwater.
Exoskeletons are most characteristic of
a. Mollusca b. Arthropoda c. Nematoda d. Chordata e. Annelida