Answer:
The gene for beta-galactosidase turns off.
Explanation:
The gene that codifies the beta-galactosidase enzyme is part of the <em>lac</em> operon, which also contains two other genes that produce enzymes involved in the metabolization of lactose.
Between glucose and lactose, the bacteria will preferentially use glucose as an energy source. On the other hand, lactose is a dimer, and thus a series of enzymes are needed to process lactose before its use as an energy source.
If there is no lactose present, the genes contained inside this operon are turned off (the operon is repressed).
The CNS involves the brain and spinal cord and the PNS involves the body nerves.
Answer:
a) The expected phenotype of the F1 plants is 100% RrBb, red kernels.
b) The expected phenotypic classes in the F2 are: 9:3:3:1
9/16 R-B-, 3/16 rrB-, 3/16 R-bb, 1/16 rrbb
Proportions 9:6:1.
9/16 Red kernel (R-B-), 6/16 Brown kernel (rrB- + R-bb), 1/16 White kernel (rrbb)
Explanation:
<u>Available data:</u>
- brown kernel: R-bb or rrB-
1º Cross) RRBB x rrbb
F1) 100% RrBb (red kernels)
2ºCross) RrBb x RrBb
Gametes) RB RB
Rb Rb
rB rB
rb rb
Punnet Square) RB Rb rB rb
RB RRBB RRBb RrBB RrBb
Rb RRBb RRbb RrBB Rrbb
rB RrBB RrBb rrBB rrBb
rb RrBb Rrbb rrBb rrbb
F2) Phenotypic classes:
<em>9/16 R-B-</em>
<em> 3/16 rrB-</em>
<em> 3/16 R-bb</em>
<em> 1/16 rrbb</em>
Phenotypic proportions:
<em>9/16 Red kernel (R-B-)</em>
<em> 6/16 Brown kernel (rrB- + R-bb)</em>
<em> 1/16 White kernel (rrbb) </em>
