Answer: The lac Y and lac Z genes are turned off when lactose is present. Is a false statement about E coli and the lac operon. Therefore the correct option is A.
Explanation:
Escherichia coli is an enteric bacteria that makes use of lactose operon (or lac operon) for its lactose metabolism. The lac operon is made up of three genes which includes lacZ, lacY and Lac A. These genes are expressed only when lactose is present and glucose is absent. Also the lac repressor acts as a lactose sensor while the catabolite activation protein (CAP) acts as a glucose sensor. They help in turning on and off the genes with respect to lactose and glucose levels.
The lac Y and lac Z genes are turned off (not expressed) when glucose is present and lactose absent, but are expressed when glucose is absent and lactose present. Therefore option A is a false statement.
Answer:can a moving car be a frame of reference?
Therefore, a frame of reference can be in motion, and that motion can be of several different types. Anyone who has ever taken a ride in a car has been in a moving frame of reference and has experienced the several different types of motion through which this frame can move.
Explanation:
Answer:
(i) The velocity in the pipe is 0.71 m/s
(ii) A pipe diameter of 0.0029 m (0.29 cm) should be used
Explanation:
(i) Velocity (V) = Reynolds number × viscosity/density × diameter of pipe
Reynolds number = 1300
Viscosity = 0.21 Pa.s
Density = 855 kg/m^3
Diameter of pipe = 45 cm = 45/100 = 0.45 m
V = 1300×0.21/855×0.45 = 0.71m/s
(ii) Pipe diameter (D) = Reynolds number × viscosity/density×velocity
Reynolds number = 1300
Viscosity = 0.0015 Pa.s
Density = 955 kg/m^3
Velocity = 0.71 m/s
D = 1300×0.0015/955×0.71 = 0.0029 m (0.0029×100 = 0.29 cm)
Answer:
object would move but it could be difficult to slow down or stop.
