Lipids (Part 11 of 11) - Sterols / Steroids
Summary
TLDRThis video script delves into the world of lipids, focusing on sterols and steroids, which share a common steroid nucleus structure. It explains their roles as membrane components and signaling molecules, with cholesterol being a key player in maintaining membrane fluidity. The script also covers bile acids' role in fat emulsification and the significance of steroid hormones, such as testosterone and estradiol, in the body. It touches on corticosteroids, including cortisol and aldosterone, and their impact on stress response and mineral balance. The video concludes with synthetic corticosteroids like prednisone, highlighting their anti-inflammatory properties and potential risks.
Takeaways
- 🌟 Sterols and steroids are lipids with a basic structure based on a steroid nucleus, which includes four rings: three six-membered rings and one five-membered ring.
- 🔍 Steroids function as membrane components and signaling molecules, such as hormones.
- 🧬 Cholesterol is the major sterol in animals, playing a crucial role in maintaining membrane fluidity and serving as a precursor to other steroid molecules.
- 🔢 The numbering system of cholesterol is important for understanding enzyme names and their functions in converting one steroid molecule to another.
- 🍗 Bile acids, a type of steroid, help emulsify fats from our diet, making them more accessible for lipases to break down further.
- 🚹🚺 Sex steroids, such as testosterone and estradiol, are produced in the reproductive organs and are involved in various physiological processes.
- 🌡 Corticosteroids, including glucocorticoids and mineralocorticoids, are produced in the adrenal cortex and have effects on blood glucose levels and mineral balance in the body.
- 💊 Synthetic corticosteroids, like prednisone, are used to treat anti-inflammatory diseases and have immunosuppressive effects, which can increase susceptibility to infections.
- 🔬 Steroid hormones, including sex steroids and corticosteroids, exert their effects by altering gene transcription within cells.
- 📚 Understanding the structure and function of steroids is essential for studying various biological pathways and their roles in health and disease.
- 📈 The video aims to provide a comprehensive wrap-up of lipids, focusing on the importance of sterols and steroids in biological systems.
Q & A
What is the basic structure of all steroids?
-The basic structure of all steroids is based on a steroid nucleus, which consists of four rings: three six-membered rings (A, B, and C rings) and one five-membered ring (D ring). This structure is nearly planar.
What roles do sterols and steroids play in biological membranes?
-Sterols and steroids function as membrane components and help maintain membrane fluidity. They prevent the membrane from becoming too rigid or too fluid, thus maintaining optimal fluidity levels.
What is the primary sterol found in animals and what is its main function?
-The primary sterol in animals is cholesterol. It plays a crucial role in maintaining membrane fluidity and serves as a precursor to other steroid molecules.
How does cholesterol's amphipathic nature contribute to its function in biological membranes?
-Cholesterol's amphipathic nature, with both polar and non-polar portions, allows it to interact with the phospholipids in the membrane, contributing to the membrane's fluidity and stability.
Why is the numbering system of cholesterol important in understanding steroid metabolism?
-The numbering system of cholesterol is important because it helps in identifying the carbon atoms involved in enzymatic reactions that convert one steroid molecule to another, which is essential for understanding steroid metabolism pathways.
What is the function of bile acids in the human body?
-Bile acids function to emulsify fats from our diet, breaking them down into smaller molecules that lipases can act upon for further digestion.
Can you explain the difference between sex steroids and corticosteroids?
-Sex steroids, such as testosterone and estradiol, are produced in the reproductive organs and are involved in sexual development and function. Corticosteroids, on the other hand, are produced in the adrenal cortex and are involved in stress response and regulation of blood glucose and mineral balance.
What is the role of aldosterone in the body?
-Aldosterone is a mineralocorticoid that plays a role in regulating sodium levels in the body, which in turn affects blood pressure and fluid balance.
What is the purpose of synthetic corticosteroids like prednisone in medical treatments?
-Synthetic corticosteroids like prednisone are used to treat anti-inflammatory diseases and act as immunosuppressants, reducing inflammation and immune responses.
Why might patients taking synthetic corticosteroids be more susceptible to infections?
-Patients taking synthetic corticosteroids may be more susceptible to infections because these drugs suppress the immune system, reducing the body's ability to fight off pathogens.
How do steroid hormones exert their effects within the body?
-Steroid hormones exert their effects by altering gene transcription within the nucleus of cells, leading to changes in cellular function and response.
Outlines
🧪 Sterol and Steroid Basics
The first paragraph introduces the basic structure of sterols and steroids, which is based on a steroid nucleus consisting of four rings: three six-membered rings and one five-membered ring. These molecules are nearly planar and are referred to as the A, B, C, and D rings. Steroids function as membrane components and signaling molecules, such as hormones. Cholesterol, the major sterol in animals, is highlighted for its amphipathic nature, with a small polar group and a large non-polar hydrocarbon portion, allowing it to maintain membrane fluidity. The paragraph also discusses the importance of cholesterol's numbering system for understanding enzyme names and functions in steroid pathways, such as the conversion of testosterone to dihydrotestosterone by 5-alpha reductase.
🌿 Bile Acids and Steroid Hormones
The second paragraph delves into bile acids, which are steroids that emulsify fats from our diet, breaking them into smaller molecules for lipases to further break down. The specific bile acid taurocholic acid is mentioned, highlighting its torine portion that carries the acidic group. The paragraph then transitions to steroid hormones, focusing on sex steroids produced in the reproductive organs: testosterone in the testes and estradiol in the ovaries. The names of these hormones are explained in relation to their structures. Corticosteroids, produced in the adrenal cortex, are also discussed, with cortisol as a stress hormone and aldosterone affecting sodium levels. A synthetic corticosteroid, prednisone, is mentioned for its use in treating anti-inflammatory diseases and its immunosuppressive effects, which can increase susceptibility to infections.
📚 Conclusion on Steroids and Lipids
The final paragraph wraps up the discussion on lipids by emphasizing the importance of steroid hormones as signaling molecules that can alter gene transcription within cells. It encourages viewers to like, comment, subscribe, and share the video if they found it helpful, and wishes them happy studying.
Mindmap
Keywords
💡Sterols and Steroids
💡Cholesterol
💡Membrane Fluidity
💡Bile Acids
💡Steroid Hormones
💡Testosterone
💡Estradiol
💡Corticosteroids
💡Cortisol
💡Aldosterone
💡Prednisone
Highlights
Introduction to sterols and steroids, emphasizing their basic structure based on a steroid nucleus with four rings.
All steroids share the same four ring system, with slight variations distinguishing different types.
Steroids function as membrane components and signaling molecules, such as hormones.
Cholesterol is the major sterol in animals, playing a key role in maintaining membrane fluidity.
Cholesterol's amphipathic nature allows it to have both polar and non-polar portions, contributing to its role in membranes.
The importance of cholesterol's numbering system for understanding enzyme actions in steroid molecule conversions.
Bile acids, as steroids, emulsify dietary fats, making them more accessible for lipases to break down.
The role of bile acids in facilitating the digestion of fats through emulsification.
Steroid hormones, including sex steroids and corticosteroids, are produced in reproductive and adrenal organs.
Testosterone and estradiol are the primary male and female sex steroids, respectively.
Corticosteroids, such as cortisol and aldosterone, are involved in stress response and mineral balance.
The naming conventions of steroid hormones can sometimes reflect their chemical structures.
Prednisone, a synthetic corticosteroid, is used for treating anti-inflammatory diseases and as an immunosuppressant.
The potential risks of using immunosuppressant drugs like Prednisone, including increased susceptibility to infections.
Steroid hormones exert their effects by altering gene transcription within the cell nucleus.
The video aims to introduce and summarize the topic of steroids within the broader context of lipids.
Encouragement for viewers to like, comment, subscribe, and share the video for further educational content.
Transcripts
hey folks if you'd like to support me or
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and enjoy the
video I'd like to wrap up the discussion
of lipids by talking about sterols and
steroids um so their basic structure is
based on this idea of a steroid
nucleus steroid nucleus which I've drawn
here it's these this four ring system
three of them are six membered rings and
this last one is a five membered ring
and this whole situation is nearly
planer the Rings are referred to as the
a ring B ring C- ring and D
ring now so all steroids have this basic
structure B this basic four ring system
they vary slightly from one to the other
but they have that same same sort of
situation going on their functions they
function as membrane
components and they can also function as
um signaling
molecules namely
hormones the
major stero in animals is
cholesterol and its structure is like
this
it looks like
that it is a a it is an
amphipathic molecule which means it has
polar and non-polar portions its polar
portion is actually pretty small it's
just this o group here right it's got a
polar o the rest of the molecule though
is just hydrocarbons right carbons and
hydrogen so the rest of it is non-polar
which is why it can actually be a
membrane
component it um specifically in
membranes it plays a role in maintaining
membrane
fluidity so if it gets too cold and a
membrane sort of begins to become more
rigid cholesterol play a role in helping
it become more fluid and if it becomes a
little bit too fluid and might break
apart it becom allows it to become a
little bit more rigid uh to maintain
optimal fluidity levels so cholesterol
plays an important role there it's also
important as a precursor to other
steroid
molecules in fact um something that's
actually pretty important to that is uh
the numbering system of cholesterol it's
27 carbons long and it's numbered like
this starting from carbon number one
right there and we go around 1 2 3 4 5 6
7 8 9 10 then we jump up here to 11 12
13 14 15 16 17 then these two methyl
groups 18 19 and then 20 through 27 are
on this this over
here um this the numbering system might
not seem really important right now but
there are certain enzymes involved in
the in sort of converting one am or what
excuse me not one amino acid one uh
steroid uh molecule to another and the
the names of the enzymes sometimes refer
to where they're actually doing whatever
it is they're doing uh for as an example
there's an enzyme
called there's an enzyme called five
Alpha reductase and what that does that
molecule is actually what takes
testosterone
testosterone and turns it into uh uh di
dihydrotestosterone which or or
DHT and the enzyme name five Alpha
reductase it's action it's it's reducing
the five carbon of testosterone to to
become uh dihydrotestosterone or DHT so
that's just one example there are other
examples but the point is that being
familiar with the numbering system of
the steroids is helpful in understanding
the names of the enzymes in case you're
studying those
Pathways okay next up here bile acids so
there are bile acids uh that are that
are
steroids and their their function really
is to emulsify fats from our diet and
what that means is basically it takes
these these gigantic fats that we're
consuming and breaks them up into little
smaller sort of uh molecules that that
lipases can act on uh and lipases will
go through and and and break down the
fats further from there so I've just
drawn here an example of a specific bile
acid called toolic acid and the reason
the tooro portion of that name comes
from this portion up here called torine
and that torine portion actually carries
the acidic um the acidic group that is
carrying the negative charge after it
has been
[Music]
deprotonated now steroid hormones
steroid hormones so these are the ones
that I think a lot of people study uh
these first two up
here are the sex steroids and they are
made in the reproductive
organs so over here I've drawn the male
sex steroid and over here I've drawn the
female sex
steroid the male sex steroid is made in
the male reproductive organ which is the
testes and the female sex steroid is
made in the ovaries the female
reproductive
organ so which
two steroids are these you may already
have guessed it this one is testosterone
and this one is
estradiol the names can make a little
bit of sense um this this uh test refers
to the fact that these things are made
in the testes uh stair comes from uh the
SD steroid and then o refers to Ketone
so we got a ketone right there so it's
basically saying male sex steroid and it
has a ketone in it
um estradiol estra refers to
estrus um and the the diol refers to two
alcohols there's an alcohol there and an
alcohol there so these names can make a
little bit of sense they're not always
Sure Fire um but they can they can
sometimes make a little bit of
sense um okay next up three and four
three and four are the
corticosteroids because they are made in
the
adrenal cortex so cortex cortico
corticosteroids they're also called
corticoids for
short uh the first one over here to the
left is a
glucocorticoid and this one over here to
the right is a um
mineralocorticoid mineralo
corticoid and you may have guessed the
names of these this one is cortisol and
this one is
aldosterone cortisol is a stress hormone
and the reason it's called a
glucocorticoid is because of its effect
on blood glucose
levels aldosterone is a mineral
corticoid because of its effects on the
minerals in our body specifically uh
sodium right sodium is a mineral and so
aldosterone uh plays a role in uh sodium
levels so so it's a mineralocorticoid
and the own again again here the own
refers to Ketone um cortisol also has a
ketone but ites doesn't have it it
doesn't end in own but up here it does
have some alcohols so that o might refer
to these alcohols up
here um cortisol's name doesn't really
lend too much to its structure um but
cortisol and aldosterone are both
corticoids because they were made and
released from the adrenal
cortex this last one here number five is
uh a synthetic corticoid oh synthetic
corticosteroid synthetic kod Co steroid
and it's actually called uh prazone okay
so prazone is used uh to treat um
anti-inflammatory
diseases anti-inflammatory
diseases um and it is an
immunosuppressant
drug so though it can treat
anti-inflammatory diseases um because of
its
immunosuppressive um effects it can
leave Pat patients susceptible to
infections so um I don't know I'm just
as soon as I I heard that I thought okay
so if someone is taking Prednisone for
some sort of disease we might want to
make sure that you know we make sure
that everything that we give them is
pretty clean and free from infections
because they're especially susceptible
to
infections now all these steroid
hormones can basically are important in
signaling so because they are steroid
hormones they can um they will uh
somehow make their way to the the
nucleus of of
um of a cell and alter Gene
transcription these guys alter they
exert their Effects by altering
transcription
of of
genes okay well I hope that video was
helpful in kind of introducing steroids
and wrapping up lipids thanks for
watching yo if you found that video
helpful don't forget to like comment
subscribe for more content and if you
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thanks happy studying
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