Chapter 3 Flashcards
what are the prefixes of compounds from 1 to 12 carbons in a chain (no branching)
What is the MF for non branching carbon chains
what are alkanes
*only carbon and hydrogen atoms
*only single bonds (saturated of H atoms)
what suffix does groups take when in the form of substituents?
-yl
From which end of the parent chain do you have to start numbering?
end that has the highest priority group
What’s the decreasing order of priority for numbering the main chain?
carboxylic acid>aldehyde>ketone>alcohol>amine>alkene>alkyne>alkyl (R) and halides
when name of compound given how do we determine the end where we start numbering?
the end with the last suffix in the name
What exactly is considered the parent chain?
longest continuous carbon chain with the most substituents connected to it
How do you determine the order which to name substituents? How/where is it named?
alphabetically
as prefix(-yl) of the main chain
When is unsaturation named?
immediately after the parent chain in the name
When are functional groups named in the name? And how do they appear?
after unsaturation
as suffixes
When is stereoisomerism named?
they appear first before substituents
What are the rules for putting the names together?
What should you do first when trying to name a compound?
What is the classification of carbon atoms?
*not to be confused with the numbering of carbon atoms
name this
name this
name this
How do you name a substituent that has two or more of the same group on the same carbon?
name this
What do we do of the substituents are at equal distance from either end of the main chain?
chose the name that gives the lower numbering at the first point of difference
How do you decide which subst takes the lowest number when equidistant from either ends of main chain?
alphabetical order: lower alphabet=lower number
what is the general formula for cycloalkanes?
how do you name cycloalkanes?
what do you change from the name of cycloalkanes when they are alkyl groups?
How else do you call E/Z isomers for cyclics?
just cis and trans
what is the difference between naming a compound cycloalkyl-alkane or alkyl-cycloalkane?
name this
name this
what happens when both alkane and cyclalkane have the same number of c atoms?
the naming system is alkyl-cycloalkane
What is a rule of rings that have more than one substituents when it comes to the direction of numbering?
Explain this:
hoe do you name branched (complex substituents)?
*name of the branch is 6-(2-methylbutyl)
name this
how do you use common acceptable IUPAC names?
what to do when more than one ring is attached to an alkane?
name the compound cycloalkylalkane
how do you name alkyl halides?
How do alcohols appear as bondline and how are they written in the name?
what is the general formula for alkenes?
what type of bonds are found in alkene and cycloalkenes?
double bonds
When and how does the numbering of alkenes is named?
How do you number cycloalkenes?
How do you name alkenes and cycloalkenes with two or more double bonds?
how do you name alcohols containing double bonds? priority? suffix?
Explain the stereochemistry of double bonds:
what is cis and trans
Explain the stereochemistry of cyclics:
what is cis and trans
What is E/Z and when are they typically used?
How do you name alkynes? suffix? priority?
general formula of alkynes
what are the five columns? (general format of names)
What is functional class naming system?
what are the three non covalent interractions?
London dispersion forces, dipole–dipole interactions, and hydrogen bonding.
What determines the boiling point of a compound, and why is it essential for vaporization to occur?
determined by the strength of the attractive forces between individual molecules. For vaporization to occur, these forces must be overcome
How do strong attractive forces between molecules influence the boiling point of a compound?
If a compound’s molecules are held together by strong forces, a significant amount of energy is required to pull the molecules away from each other. Consequently, the compound will have a high boiling point.
Are alkanes polar? why?
Alkanes, composed of carbon and hydrogen, have nonpolar bonds due to the similar electronegativities of carbon and hydrogen. The lack of significant partial charges on the atoms results in alkanes being neutral nonpolar molecules, giving them an oily feel.
What factors determine the strength of London dispersion forces in alkane molecules?
epends on the area of contact between the molecules. The greater the area of contact, the stronger the London dispersion forces. Boiling points of alkanes increase with molecular weight as each additional methylene (CH2) group increases the area of contact.
ow does branching affect the boiling point of alkane molecules, and why does branching reduce the boiling point?
Branching lowers a compound’s boiling point by reducing the area of contact between molecules. Highly branched molecules have less surface area in contact compared to their unbranched counterparts. As a result, if two alkanes have the same molecular weight, the more highly branched one will have a lower boiling point.
How do hydrogen bonds’ strength compare to other dipole-dipole interactions and LDF?
Hydrogen bonds are stronger than other dipole–dipole interactions, which are stronger than
London dispersion forces.
in what arrangement are the strongest hydrogen bonds?
linear - the two electronegative atoms and the hydrogen between them lie on a straight line.
What makes alcohols have higher boiling points than ethers despite their similar weight?
they have many hydrogen bonds and overall requires more energy to break the bonds
Do molecules with net dipole moments repel or attract each other in space?
Attract
how do hydrogen bonding work?
Why would two constitutional isomers have very different BP?
one has hydrogen bonds and the other dipole-dipole interactions only
What type of interactions do hydrocarbons mainly have?
LDF
What does the strength of LDF depend on?
surface area of hydrocarbons:
Are hydrocarbons polar molecules?
no
As hydrocarbons get large, the more _______ and higher _______
more polarizable
higher MP and BP
What is polarizability of a molecule?
How do cycloalkanes compare to their corresponding alkanes in terms of BP and MP?
Which is more stable ? branched or unbranched molecules? why?
What are the solubility rules?
What are the solubility trends of alcohols, amines and carboxilic acid?
Compare branched to unbranched by contact surface, LDF, BP, MP, delta H and stability
answer by most linear or more branched
most linear, most branched
what are conformations
what are conformers?
Which molecular stucture is used for conformers
newman projection
How are compounds only containing carbon and hydrogen called?
hydrocarbons
What are homologous series?
family of compounds in which each member differs from the one before it in the series by one methylene (CH2) group.
What are the members of a homologous series called?
homologues
Name CH3CH2CH2CH3
butane
Name CH3CH3
ethane
Name CH3CH3
ethane
Name CH4
methane
Which of the four has one alternate structure. How is it called?
methane CH4; ethane C2H6; propane C3H8; butane C4H10
butane C4H10
isobutane
What is a carbon bonded to 1 H and 2 CH3 groups called?
an ”iso“ structural unit
What is the systematic name of isoheptane?
2-methylhexane
What is an alkyl group?
Removing a hydrogen from an alkane
What is another name for an alkyl group?
alkyl substituent
What does the R- in some structure represent?
an alkyl group
If a hydrogen in an alkane is replaced by an OH, the compound becomes an ________.
alcohol
If a hydrogen in an alkane is replaced by an NH2, the compound becomes an ________.
amine
If a hydrogen in an alkane is replaced by an halogen, the compound becomes an ________.
alkyl halide
If a hydrogen in an alkane is replaced by an OR, the compound becomes an ________.
ether
how do you make a propyl group versus an isopropyl group?
What is up with these two structures?
They are identical
What are the rules for naming butyl groups?
*butyl and isobutyl groups, have a hydrogen removed from a primary carbon.
*sec-butyl group has a hydrogen removed from a secondary carbon (sec-, sometimes abbreviated s-, stands for secondary)
*tert-butyl group has a hydrogen removed from a tertiary carbon (tert-, often abbreviated t-, stands for tertiary). A tertiary carbon is bonded to three other carbons.
Why can the “sec-“ be only used by the butyl group?
*A chemical name must specify one compound only.
Why can’t “sec-pentyl” group exist?
*removing a hydrogen from a secondary carbon of pentane produces one of two different alkyl groups, depending on which hydrogen is removed
ex: sec-pentyl chloride would specify two different alkyl chlorides, so it is not a correct name.
Which alkyls can use the prefix “tert-“?
both tert-butyl and tert-pentyl compounds
*“tert-hexyl” cannot be used because it describes two different alkyl groups.
What does tert-butyl and tert-pentyl look like in bondline?
What does sec-butyl look like in bondline?
Whenever the prefix “iso” is used, how are the iso structural unit and the group replacing a hydrogen placed?
the iso structural unit is at one end of the molecule and the group replacing a hydrogen is at the other end
What exactly is an iso group?
a methyl group on the next-to-the-last carbon in the chain
What is the same for substituent placement for all isoalkyl compounds but different for isopropyl?
all isoalkyl compounds have the substituent (OH, Cl, NH2, and so on) on a primary carbon, except for isopropyl, which has the substituent on a secondary carbon.
How can a sec-propyl also be called?
isopropyl
How is the substituent in red called?
1. using common name
2. using IUPAC (systematic)
- isopropyl
- 1-methylethyl
How is the substituent in red called?
1. using common name
2. using IUPAC (systematic)
- isobutyl
- 2-methylpropyl
How is the substituent in red called?
1. using common name
2. using IUPAC (systematic)
- sec-butyl
- 1-methylpropyl
How is the substituent in red called?
1. using common name
2. using IUPAC (systematic)
- tert-butyl
- 1,1-methylethyl
How is the substituent in red called?
1. using common name
2. using IUPAC (systematic)
- isopentyl
- 3-methylbutyl
How is the substituent in red called?
1. using common name
2. using IUPAC (systematic)
- isohexyl
- 4-methylpentyl
Do common names require numbering?
Only systematic names have numbers; common names never contain numbers.
Which one is a correct name?
B
How do you name and number substituents on a carbon ring when there is two or more?
*listed in alphabetical order, and the substituent given the number-1 position is the one that results in a second substituent getting as low a number as possible.
*If two substituents have the same low numbers, the ring is numbered—either clockwise or counterclockwise—in the direction that gives the third substituent the lowest possible number.
What is an alkyl halide?
How are they classified?
*compound in which a hydrogen of an alkane has been replaced by a halogen
*primary, secondary, or tertiary, depending on the carbon to which the halogen is attached
How do you name alkyl halides?
- common name
- systematic name
*common name:
name of the alkyl group, followed by the name of the halogen—with the “ine” ending of the halogen name (fluorine, chlorine, bromine, and iodine) replaced by “ide” (fluoride, chloride, bromide, and iodide)
*systematic name:
alkyl halides are named as substituted alkanes. The prefixes for the halogens end with “o” (that is, fluoro, chloro, bromo, and iodo).
What is an ether?
What are the two types?
How do you name ethers?
1. common name
2. systematic name
- names of the two alkyl substituents (in alphabetical order), followed by the word “ether”
- as an alkane with an RO substituent. The substituents are named by replacing the “yl” ending in the name of the alkyl substituent with “oxy.”
How do you name alcohols?
1. common name
2. systematic name
- name of the alkyl group to which the OH group is attached, followed by the word “alcohol.”
- replacing the “e” at the end of the name of the parent hydrocarbon with “ol.”
When necessary, the position of the functional group is indicated by a number immediately preceding the name of the parent hydrocarbon or immediately preceding the suffix.
If there are two OH groups, the suffix “diol” is added to the name of the parent hydrocarbon.
What is the difference between primary, secondary and tertiary amines?
depending on how many alkyl groups are attached to the nitrogen:
What is an amine?
compound in which one or more hydrogens of ammonia have been replaced by alkyl groups.
How do you name amines?
1. common name
2. systematic name
- names of the alkyl groups bonded to the nitrogen, in alphabetical order, followed by “amine.” The entire name is written as one word (unlike the common names of alcohols, ethers, and alkyl halides
- The “e” at the end of the name of the parent hydrocarbon is replaced by “amine”
a number identifies the carbon to which the nitrogen is attached, and the number can appear before the name of the parent hydrocarbon or before “amine.”
The name of any alkyl group bonded to nitrogen is preceded by an “N” (in italics) to indicate that the group is bonded to a nitrogen rather than to a carbon.
doesn’t matter substituent on a carbon or a nitrogen, they are placed in alphabetical order.
How do you name nitrogen compounds with four alkyl groups attached to the nitrogen—thereby giving the nitrogen a positive formal charge?
they are quaternary ammonium salts
Their names consist of the names of the alkyl groups in alphabetical order, followed by “ammonium” (all one word) and then the name of the accompanying anion as a separate word.
What is the bond strength trend in alkyl halides?
the C ¬ X bond becomes longer and weaker as the size of the halogen increases because the electron density of the orbital decreases with increasing volume.
What is the structure of an alcohol?
the geometry of the oxygen in an alcohol; it is the same as the geometry of the oxygen in water
oxygen in an alcohol is sp3 hybridized, as it is in water. Of the four sp3 orbitals of oxygen, one overlaps an sp3 orbital of a carbon, one overlaps the s orbital of a hydrogen, and the other two each contain a lone pair.
What is the structure of alkyl halides?
like alkanes but a halogen replaces a hydrogen
What is the structure in ethers?
oxygen in an ether same geometry as the oxygen in water.
same structure as a water molecule with alkyl groups in place of both hydrogens
What is the structure of amines?
nitrogen in an amine same geometry as the nitrogen in ammonia
nitrogen is sp3 hybridized as in ammonia, with one, two, or three of the hydrogens replaced by alkyl groups. (primary, secondary, or tertiary)
How does branching affect boiling points?
Branching decreases boiling points by reducing the area of contact between molecules.
Highly branched molecules have lower boiling points compared to their unbranched counterparts of the same molecular weight.
What other force than LDF affect the boiling points of a series of ethers, alkyl halides, alcohols, or amines?
dipole-dipole interactions
the polar C ¬ Z bond. Recall that the C ¬ Z bond is polar because nitrogen, oxygen, and the halogens are more electronegative than the carbon to which they are attached
Why are molecules with polar bonds attracted to one another?
because they can align themselves in such a way that the positive end of one dipole is adjacent to the negative end of another dipole.
Do ethers or alkanes have higher bp for the same molecular weight? Why?
Ethers generally have higher boiling points than alkanes of comparable molecular weight
because both London dispersion forces and dipole–dipole interactions must be overcome for an ether to boil.
What is a hydrogen bond?
a special type of dipole–dipole interaction between a hydrogen atom attached to an electronegative atom (such as oxygen, nitrogen, or fluorine) and a lone pair of electrons on another electronegative atom.
How does the boiling point of water compare to that of methane, and why?
Water has a much higher boiling point (100°C) compared to methane (-167.7°C) despite their similar molecular weights because water molecules can form hydrogen bonds, whereas methane molecules cannot.
Why do primary amines have higher boiling points than secondary amines?
Primary amines have stronger dipole–dipole interactions than secondary amines, making hydrogen bonding more significant. Consequently, primary amines have higher boiling points than secondary amines.
How do the boiling points of primary, secondary, and tertiary amines compare when they have the same molecular weight?
the primary amine has the highest boiling point, followed by the secondary amine, and then the tertiary amine.
Explain why H2O has a higher boiling point than CH30H
Explain why H2O has higher boiling point than NH3
How do the melting points of straight-chain alkanes with even and odd numbers of carbons differ?
alkanes with an odd number of carbons pack less tightly than alkanes with an even number of carbons
Why do alkanes with an odd number of carbons pack less tightly?
because the molecules (each a zigzag chain with its ends tilted the same way) can lie next to each other with a methyl group on the end of one facing and repelling the methyl group on the end of the other, thus increasing the average distance between the chains.
Consequently, they have weaker intermolecular attractions and correspondingly lower melting points.
How do solvent molecules interact with polar compounds?
The negative poles of solvent molecules surround the positive pole of the polar compound, and the positive poles of solvent molecules surround the negative pole of the polar compound.
How does solvation enable dissolution?
Solvation involves the clustering of solvent molecules around solute molecules, which separates them from each other and facilitates dissolution.
How many carbons can ethers drag into water?
about 3, (4 it becomes a bit insoluble)
How do primary, secondary, and tertiary amines differ in solubility in water?
Primary amines are more soluble than secondary amines with the same number of carbons because primary amines have two hydrogens that can engage in hydrogen bonding with water.
Tertiary amines are less soluble in water than secondary amines with the same number of carbons because they do not have hydrogens available to donate for hydrogen bonding.
Are alkyl halides all soluble in water, since they all have some polar character?
No, only alkyl fluorides have an atom that can form a hydrogen bond with water. Alkyl fluorides, therefore, are the most water soluble of the alkyl halides. The other alkyl halides are less soluble in water than ethers or alcohols with the same number of carbons
How does rotation about a carbon-carbon single bond affect orbital overlap?
Rotation about a carbon-carbon single bond can occur without any change in the amount of orbital overlap.
What is Newman projection?
Way of representing three-dimensional structures that result from rotation about a σ bond.
viewer is looking along the longitudinal axis of a particular C¬C bond.
carbon in front is represented by a point (where three lines are seen to intersect), and the carbon at the back is represented by a circle. The three lines emanating from each of the carbons represent its other three bonds.
What are the staggered and eclipsed conformer?
The staggered conformer and the eclipsed conformer represent two extremes resulting from rotation about a C-C bond.
How do the staggered conformer and the eclipsed conformer differ in stability and energy level?
The staggered conformer is more stable and lower in energy compared to the eclipsed conformer.
What is hyperconjugation, and how does it relate to the stability of staggered conformers?
the delocalization of electrons by the overlap of a σ orbital with an empty orbital.
In staggered conformers, hyperconjugation maximizes stabilizing interactions between adjacent C-H bonds, contributing to their greater stability.
How many C-C single bonds on which rotation can occur is there in butane?
Butane has three carbon–carbon single bonds, and rotation can occur about each of them.
How do you draw newman projection? use butane as an example
the carbon with the lower number is placed in the foreground
Are all staggered conformers resulting from rotation about the C₁-C₂ bond in butane energetically equivalent?
Yes
Are staggered conformers resulting from rotation about the C₂-C₃ bond in butane energetically equivalent?
No
What are the staggered and eclipsed conformers that result from rotation about the C₂-C₃ bond in butane?
What are the relative energies of these conformers?
What does the degree of rotation of each conformer correspond to?
the dihedral angle, which is the angle formed in a Newman projection by a bond on the front carbon and a bond on the back carbon.
Can you provide an example of how the dihedral angle varies between conformers?
in conformer (A) where one methyl group stands directly in front of the other, the dihedral angle is 0°. In contrast, in conformer (D) where the methyl groups are opposite each other, the dihedral angle is 180°.
What distinguishes the anti conformer from the gauche conformers among the three staggered conformers?
The anti conformer, labeled as D, has the two methyl groups positioned as far apart as possible, making it more stable and lower in energy compared to the gauche conformers (B and F).
Why are the two gauche conformers (B and F) considered to have the same energy?
The two gauche conformers (B and F) are considered to have the same energy because they share a similar spatial arrangement where the two methyl groups are closer together compared to the anti conformer, resulting in identical steric strain.
How do the energies of eclipsed conformers vary based on the positioning of the methyl groups?
The eclipsed conformer where the two methyl groups are closest (labeled as A) is less stable than eclipsed conformers where they are farther apart (labeled as C and E).
Why do carbon chains adopt zigzag arrangement? From what it this due?
They are in a zigzag formation as they are staggered
being staggered rather that in eclipse makes them more stable
therefore, leading to a higher number of molecules in staggered conformations compared to eclipsed conformations
How did Baeyer suggest determining the stability of a cycloalkane based on bond angles?
by calculating the difference between the ideal bond angle (109.5°) and the actual bond angle in the planar cycloalkane.
For example, the bond angles in cyclopropane are 60°, representing a 49.5° deviation from 109.5°
Represent the angle strain in cyclopropane by drawing the overlap of the orbitals compared to a normal σ bond.
Typically, σ bonds are formed by the direct overlap of two sp3 orbitals.
However, in cyclopropane, the overlapping orbitals cannot point directly at each other due to the cyclical structure. As a result, the amount of overlap between the orbitals forming the C-C bonds is reduced compared to a normal C-C bond.
What is angle strain, and why does it occur in cyclopropane?
the strain caused by deviation from the ideal bond angle.
In cyclopropane, the deviation from the ideal bond angle of 109.5° results in reduced overlap between orbitals forming the C-C bonds, leading to weaker bonds and angle strain.
What else than angle strain affects the stability of cyclopropane?
In addition to angle strain in the C-C bonds, all the adjacent C-H bonds in cyclopropane are eclipsed rather than staggered, further contributing to its instability.
How does the angle strain in cyclobutane compare to that in cyclopropane?
Cyclobutane would have less angle strain than cyclopropane because its bond angles would deviate by only 19.5° from the ideal bond angle, compared to the 49.5° deviation in cyclopropane.
Why is cyclobutane not planar despite having less angle strain than cyclopropane?
because of the presence of eight pairs of eclipsed hydrogens, resulting in structural distortion. One of the CH2 groups in cyclobutane is bent away from the plane made by the three other carbons
How does cyclopentane address the issue of eclipsed hydrogens to increase stability?
Cyclopentane puckers, causing the molecule to bend out of a planar arrangement.
This puckering allows some of the hydrogens to become nearly staggered, reducing the number of eclipsed hydrogens and increasing stability.
However, this process introduces some degree of angle strain to the molecule.
How does a chair conformer differ from a planar structure?
A chair conformer is not planar; instead, it forms a three-dimensional shape resembling a lounge chair.
Unlike a planar structure with bond angles of 120°, all the bond angles in a chair conformer are approximately 111°, which is very close to the ideal tetrahedral bond angle of 109.5°.
How are the bonds arranged in a chair conformer?
all the adjacent bonds are staggered, contributing to the stability of the structure.
Draw the newman projection of the chair conformer looking down the
C-1—C-2 and C-5—C-4 bonds
What are axial and equatorial bonds in cyclohexane chair conformers and how do you draw them?
How does ring flip occur in cyclohexane, and what changes take place during this process?
Ring flip occurs due to the ease of rotation about the C-C bonds in cyclohexane. During ring flip, bonds that are equatorial in one chair conformer become axial in the other chair conformer, and vice versa.
This interchange allows the molecule to adopt different stable conformations.
What happens to equatorial and axial bonds during the ring flip of cyclohexane?
During ring flip, equatorial bonds become axial, and axial bonds become equatorial
What is the alternative conformation to the chair conformer for cyclohexane, and what is it called?
boat conformer
Why is the boat conformer less stable compared to the chair conformer?
because it contains some eclipsed C-H bonds, unlike the chair conformer.
Additionally, the boat conformer experiences steric strain due to the close proximity of the flagpole hydrogens located at the “bow” and “stern” of the boat conformation.
How does steric strain arise in the boat conformer of cyclohexane?
due to the close proximity of the flagpole hydrogens, causing repulsive interactions and destabilizing the conformation.
How does cyclohexane interconvert between the boat conformer and the chair conformer?
one of the topmost carbons of the boat conformer must be pulled down to become the bottommost carbon of the chair conformer.
What happens when the carbon in the twist-boat conformation aligns with the sides of the boat?
When the carbon in the twist-boat conformation aligns with the sides of the boat, it forms the half-chair conformation, which is highly unstable due to the strained geometry.
What does the predominance of chair conformers imply about the stability of cyclohexane conformations?
it implies that they are significantly more stable than any other conformers of cyclohexane.
How does the population distribution of cyclohexane conformers reflect their relative stability?
The population distribution of cyclohexane conformers reflects their relative stability, with the chair conformers being overwhelmingly more stable and thus more prevalent compared to other conformers.
How do the two chair conformers of a monosubstituted cyclohexane, like methylcyclohexane, differ?
the two chair conformers of a monosubstituted cyclohexane, such as methylcyclohexane, differ in the position of the methyl substituent. In one conformer, the methyl substituent is in an equatorial position, while in the other conformer, it is in an axial position.
What visual representation supports the idea that a methyl group in an equatorial position extends into space?
a methyl group in an equatorial position extends into space away from the rest of the molecule, demonstrating the increased room available for the substituent.
What is the consequence of having an axial substituent in a cyclohexane chair conformer in terms of steric interactions?
it results in the substituent being relatively close to the axial substituents on the other two carbons on the same side of the ring.
This proximity leads to unfavorable steric interactions known as 1,3-diaxial interactions.
What makes 1,3-diaxial interactions unfavorable?
because they lead to repulsive forces between the axial substituents due to their close proximity, contributing to the destabilization of the molecule.
To what type of “chain” strain can 1,3-diaxial interactions be compared to?
the gauche interaction in butane
What is the cis isomer in cyclohexanes?
both substituents are positioned on the same side of the cyclohexane ring.
What is the trans isomer in cyclohexanes?
the two substituents are positioned on opposite sides of the cyclohexane ring.
How to differentiate cis-trans isomers
(textbook p.169 if unclear)
*If the bonds bearing the substituents both point upward or both point downward, then the compound is the cis isomer; if one bond points upward and the other downward, then the compound is the trans isomer. (axial)
*if not evident, look at the axial H (or other substituent), if they are cis, the substituents are also vive versa
How do you draw the most stable conformer?
What distinguishes the trans and cis isomers in fused cyclohexane rings?
In the trans isomer of fused cyclohexane rings, one substituent bond points upward and the other downward, both in the equatorial position. In the cis isomer, one substituent is in the equatorial position, while the other is in the axial position.
What is a common structural feature of many hormones?
Many hormones are steroids, which are organic compounds characterized by a four-ring structure. These rings are designated as A, B, C, and D.
How are the B, C, and D rings arranged in steroids?
In steroids, the B, C, and D rings are all trans-fused, meaning they share two adjacent carbons and have a stable, planar configuration.
What is the typical arrangement of the A and B rings in most naturally occurring steroids?
he A and B rings are also trans-fused, similar to the B, C, and D rings. This arrangement contributes to the overall stability and structural integrity of the steroid molecule.
What is the most abundant member of the steroid family in animals, and what is its role?
Cholesterol: serves as the precursor for the synthesis of all other steroids and plays a crucial role as an important component of cell membranes.
How does the structure of cholesterol contribute to its function in cell membranes?
with its rigid and specific conformation due to locked rings: enhances membrane stability and fluidity by interacting with phospholipids, affecting their arrangement and preventing excessive fluidity or rigidity in the membrane.
What distinguishes the rigidity of cholesterol from other membrane components?
conformation of its rings, which are locked in place.
This rigidity allows cholesterol to maintain the structural integrity of the membrane while modulating its fluidity.
What is the precursor for all steroids such as cortisol, estrogen, and testosterone, as well as vitamin D?
cholesterol
