Negative control of the lac operon. 

No lactose; repression. The lacI gene produces repressor, which binds to the operator and blocks RNA polymerase from transcribing the lac genes.

TLS Online TPP Program

#Id: 1260

#Unit 7. System Physiology – Animal

The cells of the adrenal cortex contain large amounts of smooth endoplasmic reticulum, which is involved in the steroid-forming process.

TLS Online TPP Program

#Id: 1261

#Unit 7. System Physiology – Animal

The hormones of the adrenal cortex are derivatives of cholesterol.

TLS Online TPP Program

#Id: 1262

#Unit 7. System Physiology – Animal

The adrenal cortex secretes three classes of steroid hormones:

Glucocorticoids

Mineralocorticoids

Androgens

TLS Online TPP Program

#Id: 1263

#Unit 7. System Physiology – Animal

The innermost zone of the cortex, zona reticularis, and the middle zone, zona fasciculata, synthesize and secrete glucocorticoids and adrenal androgens. 

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#Id: 1264

#Unit 7. System Physiology – Animal

The outermost zone, called the zona glomerulosa, secretes mineralocorticoids.

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#Id: 1265

#Unit 7. System Physiology – Animal

The conversion of cholesterol to pregnenolone, catalyzed by cholesterol desmolase, in mitochondria.