Question

1.Draw the backbone that is in common for all steroids. From the family of steroids, name 2 classes of sex hormones, 2 classes of corticoid hormones, and 1 class of synthetic steroids. For each class, name a representative example, indicate where the hormones are synthesized and what biochemical/physiological reaction it is involved in (10 points). 2.Using the information that you know and the following structures, draw the structures for the following disaccharides. Be sure to specify what type of bond is used (10 points): Sucrose Maltose Lactose 3. A 10kb fragment is digested with restriction endonuclease EcoRI yielded fragments 4kb and 6kb in size. When digested with BamHI, fragments 1, 3.5, and 5.5kb were generated. Concomitant digestion with both EcoRI and BamHI yielded fragments 0.5, 1, 3, and 5.5kb in size. Draw a picture of what the gel would look like with given the above information. Give a possible restriction map for the fragment (10 points). 4.The result of sequence determination by the Sanger dideoxy chain termination method is displayed below. What is the sequence of the original oligonucleotide? Draw the first 4 bases as a tetranucleotide (10 points)? 5. Proteins are common components of a cell. They can serve structural or enzymatic roles in the cell. Often they are associated with cell membranes. Differentiate between extrinsic and intrinsic proteins. Proteins that are embedded into the plasma membrane are often anchored via one of four methods. Define and describe each protein anchor type (10 points).

Answer 1

1.

The steroid core structure is composed of 17 carbon atoms bonded in four fused rings.

Steroid sex hormones:

1. Estrogens : example - estradiol

Produced by the follicles of the ovary and is responsible for development of female secondary sexual characters.

2. Androgens : example- testosterone

Produced by testicles in males. It is responsible for development of male sexual characteristics.

Steroid corticoid hormones:

1. Glucocorticoids : example- cortisol

It is produced by zona fasciculata of adrenal cortex and performs immunosuppeession.

2. Mineralocorticoids : example - aldosterone

It helps in regulating blood pressure through water and electrolyte balance. It is produced by zona Glomerular of adrenal cortex.

Synthetic steroids:

Progestins : example- danazol

Used in the treatment of endometriosis.