Which of the following best describes the connection between cardiovascular disease and
2 answers:
Which of the following best describes the connection between cardiovascular disease and age?
O A. As people age, their blood vessels become more elastic leading to less cardiovascular disease.
O B. As people age, the heart becomes more efficient with each pump, increasing cardiac output
O C. As people age, blood pressure decreases leading to more cardiovascular disease.
O D. As people age, plaque builds up in the arteries increasing vessel resistance, which leads to disease.
- D. As people age, plaque builds up in the arteries increasing vessel resistance, which leads to disease.
Plaque development can restrict these arteries, reducing blood flow to the heart. Reduced blood flow may eventually result in chest pain and shortness of breath A heart attack might be caused by a total blockage.
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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.
