Taiben went on a walk in the forest. He saw a deer grazing in the grass, a bird eating a berry, a fish swimming in a creek, and
2 answers:
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I have attached lac operon model having 4 genes. See attachment for better understanding.
Answer:
The Lac operon is controlled by two signals.
Initiation
Glucose and lactose concentrations control the initiation of transcription of the Lac operon through their effects on the Lac repressor protein and Cap.
Lactose absent (Repression)
When lactose is absent, the Lac repressor binds the Lac operator and shuts off expression of the operon.
Lactose present (Transcription)
Addition of lactose increases the intracellular concentration of a related compound, allolactose. allolactose binds to the Lac repressor, causing it to undergo a conformational change that releases its grip on the operator DNa.
Glucose absent (Repression)
When glucose is absent, cyclic aMp (red triangle) is produced by the cell and Cap binds to DNA.
Glucose present (Transcription)
LacZ, the first gene of the operon, encodes the enzyme b-galactosidase, which breaks down lactose to galactose and glucose.
Answer:
Because the offspring of a male and female are always going to be xx, xx, xy, or xy.
Explanation:
Remember that men have different reproductive chromesomes than women. Women have 2 x chromesomes(xx) while men have 1 x and 1 y(xy). These are given down to their offspring.
So we can write the this out in a punnet square as(link down below).
After you see the visual, you will find that the genotypes are xx, xx, xy, xy.
As I said above, women have sex chromesomes xx, while men have sex chromesomes xy. When you match the genotypes on the punnet square with the ones we know from men and women, we find that two of them match with men and two match with female.
So with this, we can conclude that 2/4 of offspring will always be male and 2 will be female. And as you well know 2/4 is 1/2 which is 50%.
