Podcast
Questions and Answers
What is a steroid?
What is a steroid?
An organic compound with four rings arranged in a specific molecular configuration.
The steroid core structure is composed of _____ carbon atoms, bonded in four 'fused' rings.
The steroid core structure is composed of _____ carbon atoms, bonded in four 'fused' rings.
seventeen
Which ring structure is present in steroids?
Which ring structure is present in steroids?
Cholesterol is the only known steroid found in animals.
Cholesterol is the only known steroid found in animals.
Signup and view all the answers
What is the significance of the aromatic ring with C-3 OH in steroids?
What is the significance of the aromatic ring with C-3 OH in steroids?
Signup and view all the answers
What is the role of modifications at the 16 and 17 positions in steroids?
What is the role of modifications at the 16 and 17 positions in steroids?
Signup and view all the answers
What are the common examples of estrogens?
What are the common examples of estrogens?
Signup and view all the answers
Match the steroid with its category:
Match the steroid with its category:
Signup and view all the answers
The side chain of steroids can be found at the _____ position.
The side chain of steroids can be found at the _____ position.
Signup and view all the answers
What is the significance of the six asymmetric carbon atoms in steroids?
What is the significance of the six asymmetric carbon atoms in steroids?
Signup and view all the answers
Steroids contain fatty acids.
Steroids contain fatty acids.
Signup and view all the answers
Study Notes
Steroids
- Steroids are organic compounds characterized by four rings arranged in a specific molecular configuration, known as the cyclopentanoperhydrophenanthrene nucleus.
- The four rings consist of three six-member cyclohexane rings (A, B, and C) and one five-member cyclopentane ring (D).
- Steroids are distinguished by the functional groups attached to this core structure and the oxidation state of the rings.
Numbering of Steroids
- The steroid core structure comprises 17 carbon atoms bonded in four fused rings.
- Angular methyl groups are typically found at C-10 and C-13 positions.
- An alkyl group may be present at C-17. Sterols typically have a hydroxyl group at C-3.
- A side chain is attached at the 17th position.
Properties of Steroids
- Steroids exhibit a relatively flat and rigid molecular structure.
- They possess high crystalline properties.
- Steroids are both hydrophilic and lipophilic.
- They do not contain fatty acids.
- Cholesterol, a well-known steroid, is exclusively found in animals.
SAR of Steroids
- The aromatic ring with a C-3 hydroxyl group is essential for activity.
- The 17β-hydroxyl group, maintaining a constant distance from the 3-OH, is crucial for activity.
- Unsaturation of ring B reduces activity.
- Modifications at the 16th and 17th positions can enhance activity.
Nomenclature of Steroids
- Steroids are primarily named as derivatives of basic steroidal ring systems.
- These ring systems are categorized based on the number of carbon atoms they contain:
- Gonane (C17):
- Estrane (C18): Examples include estrogens (estradiol, estrone, estriol).
- Androstane (C19): Examples include androgens (testosterone).
- Pregnane (C21): Examples include progesterone and corticosteroids.
- Cholane (C24): Examples include bile acids.
- Cholestane (C27): Examples include cholesterol.
Configuration of Steroids
- β Configuration: Substituents attached to the ring system from above are designated as β, with lines represented as thickened.
- α Configuration: Substituents attached to the ring system from below are designated as α, with lines represented as broken or dotted.
- Unknown Configuration: If the configuration of the substituent is unknown, it is represented with a wavy line.
Stereochemistry of Steroids
- The stereochemistry of the rings significantly influences the biological activity of specific steroid classes.
- The steroid nucleus contains six asymmetric carbon atoms (5, 8, 9, 10, 13, 14), potentially leading to 64 optically active forms.
- Steroids can exist in two conformations: chair form and boat form.
Notable Steroids:
-
Estrogens:
- Estrone
- Estradiol
- Estriol
- All derived from the Estrane ring system.
- C18
-
Androgens:
- Testosterone
- Derived from the Androstane ring system.
- C19
- Androst-4-en-17β-ol-3-one
-
Progesterone:
- Derived from the Pregnane ring system.
- C21
- Progest-4-en-3,20-dione
-
Cortisone:
- Derived from the Pregnane ring system.
- C21
- 17α,21-dihydroxypregn-4-en-3,11,20-trione
-
Bile acid-cholic acid:
- Derived from the Cholane ring system.
- C24
- 3,7,12-Trihydroxycholan-24-oic acid
-
Cholesterol:
- Derived from the Cholestane ring system.
- C27
- Choles-5-en-3β-ol
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge about steroids, their structures, and properties. This quiz covers the chemical configuration, numbering of carbon atoms, and characteristics of steroids, including well-known examples like cholesterol. Perfect for students of biology and biochemistry!
