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Biochemistry > Chapter 3; Lipids > Flashcards

Chapter 3; Lipids Flashcards

1
Q

Are lipids heterogenous or homogenous?

  1. Are they polymers?
  2. Study of lipids is called?
A
  1. Heterogenous
  2. Not polymers (unlike proteins, polysaccharides and nucleic acids)
  3. Lipidomics
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2
Q

Lipidz are mainly classified into?
Subclasses?

A

Mainly into;
1. Simple lipids

(Esters of fatty acids & alcohols)

•Fats and oils (triacylglycerols);
(Esters of fatty acids + glycerols)

•Waxes;
(Esters of fatty acids + alcohols—aliphatic/aromatic other than glycerols)

2. Complex (or compound) lipids
(Esters of fatty acids & alcohols + additional groups(phosphate, nitrogenous base, carbs, protein))

•Phospholipids
–(i)—Glycerophospholipids
(Alchol-glycerol
-e.g
lecithin
Cephalin
–(ii)—Sphingophospholipids
(Alchol-sphingosine
-e.g
sphingomyelin

•Glycolipids:
(Alchol-sphingosine–glycoslphingolipids)
- contain
Fatty acid
Carbohydrate
Nitrogenous base
- glycerol & phosphate—absent
-e.g
Cerebrosides
Gangliosides

•Lipoproteins

•Other complex lipids
E.g,
Sulfolipids
Aminolipids
Lipopolysaccharides

3. Derived lipids
Obtained on hydrolysis of simple lipids & complex lipids
Include;
•Glycerol & other alcohols
•Fatty acids
•Mono & di-acylglycerols
•Fat soluble vitamins
•Steroid hormones
•Hydrocarbons
•Ketone bodies

4. Miscellaneous lipids
Include;
•Carotenoids
•Squalene
•Pentacosane (an hydrocarbon in bee wax)
•Terpenes

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3
Q

What are neutral lipids?

A

Lipids which are uncharged
E.g
•Mono, di & triacylglycerols
•Cholesterol
•Cholesteryl esters

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4
Q

_____ alcohol is most commonly found in wax?

A

Cetyl alcohol

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5
Q

________ are the concentrated fuel reserve in our body? But are NOT the structural components of biological membranes?

Fast reserve of men and women?

A

Triacylglycerols

Men (20%)
Women (25%) by weight

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6
Q

Which lipids serve as cellular matabolic regulators?

A

Steroid hormones & prostaglandins

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7
Q

_______ are the carboxylic acids with hydrocarbon side chain & are the simplest form of lipids

Occurs mainly in which form

Of _____ origin are much more simpler than other?

A

Fatty acid

Esterified

Of animal origin is much more simpler than that of plant

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8
Q

Fatty acids with more than 2 double bonds are known as?

A

PolyUnsaturated Fatty Acid (PUFA)

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9
Q

Saturated fatty acid end with suffix ____?
And unsaturated?

A

Saturated—- -anoic acid
(E.g octanoic acid)

Unsaturated—- -enoic acid
(E.g octadecenoic acid)

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10
Q

The terminal carbon containing methyl group is known as?

A

Omega Carbon (w)

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11
Q

Depending on length of carbon chain, fatty acids are classified into?

A

3 groups;
Short chain— < 6 C
Medium chain— 8-14 C
Long chain—-16-24C

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12
Q

Most of the fatty acids occur in natural lipids are of ____ carbons?
Name the most common?

A

even (usually 14C-20C)

Most common even carbon fatty acids;
Palmitic acid (16C)
Stearic acid (18C)

Most common odd carbon fatty acids;
Propionic acid (3C)
Valeric acid (5C)

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13
Q

The fatty acid with 20 carbon is? How many double bonds and where?

  1. How many double bonds in Oleic acid (18C) & palmitoleic acid (16C) and where?
A

Arachidonic Acid (20C)
- 4 double bonds
At; Carbon no. 5,8,11,14

  1. Both have 1 double bond at C=9
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14
Q

Naturally occuring unsaturated fatty acids belong to which omega (w) seriez?

A

1.w3 series: linolenic acid
(3 double bonds on C 9,12,15)

2.w6 series: linoleic acid
(2 double bonds on C 9,12)
Arcahidonic acid
(4 double bonds on C 5,8,11,14)

3.w9 series: oleic acid
(1 double bonds on 9)

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15
Q

Arachidonic acid becomes essential of ots precursor _____ is not provided in the diet in sufficient amount?

A

linolenic acid

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16
Q

Why linolenic and linoleic acid are essential fatty acids?

A

Because human lacks the enzyme that can induce double bond beyond carbon 9 to 10
So body can’t produce them on its own

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17
Q

What are essential fatty acids? Name?

A

That cannot be synthesized by the body so should be supplied in diet
These are polyunsaturated Fatty acids;

Lenoleic acid
Lenolenic acid
Arachidonic acid

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18
Q

Functions of EFA?

A

1.Membrane structure
2.Transport of cholesterol
3. Form lipoproteins
4. Prevention of fatty liver
5. Synthesis of eicosanoids

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19
Q

The deficiency of EFA (essential fatty acids) results in?

A

Phrynoderma or Toad skin
-horny eruptions on limbs
-loss of hair
-poor wound healing

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20
Q

What are Eicosanoids?

They include?

A

Eicosanoids are a group of bioactive molecules derived from fatty acids (EFAs), such as arachidonic acid.

They play important roles in inflammation, blood clotting, and other physiological processes.

These include;
•Prostaglandins
•Prostacyclins
•Leukotrienes
•Thromboxanes

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21
Q

What are ketone bodies?

What are they chemically?

Produced from?

A

Ketone bodies are molecules produced when the body breaks down fatty acids for energy.

  • these are derived lipids
  • Ketone bodies are used as an alternative source of energy when glucose is limited, like during fasting or low-carb diets.

2.Chemically:
Ketone bodies are chemically •acetone
•acetoacetate
•beta-hydroxybutyrate.

  1. Produced from liver
    During fasting etc
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22
Q

What is squalene?

A

squalene is a precursor molecule for the synthesis of cholesterol and other important lipids.

  • It is a Miscellaneous lipid
  • production of certain hormones.
    -as an antioxidant and helps maintain the structure and integrity of cell membranes. -Also acts as a skin moisturizer for healthy skin
  • found in animals & plants
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23
Q

What are Conditionally essential fatty acids?

A

Conditionally essential fatty acids are fatty acids that are normally produced by the body but may become essential under certain conditions, such as during periods of rapid growth, illness, or certain medical conditions (disease).

They include;
• omega-6 fatty acids like gamma-linolenic acid (GLA) and
•omega-3 fatty acids like eicosapentaenoic acid (EPA) & docosahexaenoic acid (DHA).

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24
Q

The most imortant of all conditionally essential fatty acids is?

It can be synthesized in limited amount from? But limited in?

A

docosahexaenoic acid (DHA)

a-lenuleic Acid (ALA)
But capacity to convert ALA to DHA is limited in preterm infant (premature birth)

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25
Q

Which acids are considered as heart disease fighting fatty acids?
What are their sources?

A

1•docosahexaenoic acid (DHA)
•eicosapentaenoic acid (EPA)

  1. Source
    Fish oils (shark)
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26
Q

Trans form of oleic acid?

A

The trans form of oleic acid is called elaidic acid.

It’s a type of unsaturated fatty acid.

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27
Q
  1. of the cis trans isomers, which is more stable?

2.Most of the naturally occuring unsaturated fatty acids exist as?

A

1.Trans is more stable

  1. Cis isomers
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28
Q

What is ketosis?

A

Ketosis is a metabolic state in which the body starts using ketone bodies as a primary source of fuel instead of glucose.
It occurs when carbohydrate intake is low, such as during fasting, a ketogenic diet, or intense exercise.

Ketosis can lead to increased fat burning and weight loss. It’s an interesting process!

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29
Q

Name some hydroxy fatty acids?

A
  1. B-Hydroxy Butyric acid (a ketone body produced in liver)
  2. Cerebronic acid (in brain)
  3. Recinoleic acid (from castor oil)
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30
Q

What is leprosy?
2.Which fatty acid is used for the treatment? What type of acid?
3.What does it contain?

A

Leprosy, also known as Hansen’s disease, is a chronic infectious disease caused by the bacteria Mycobacterium leprae.

It mainly affects the skin, nerves, and mucous membranes, leading to skin lesions, nerve damage, and potential deformities if left untreated. .

2.chaulmoogric acid
- a Cyclic fatty acid
-found in chaulmoogra oil (from plant)

  1. Cyclopentenyl ring
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31
Q

What are
Prostaglandins
Prostacyclins
Leukotrienes
Thromboxanes?

A

Prostaglandins —————
are a group of lipid compounds that are involved in ,
inflammation, pain, and blood clotting.
They are derived from fatty acids and play important roles in regulating many bodily functions.

Prostacyclins—————
are a type of prostaglandins that are involved in regulating blood vessel dilation and preventing blood clotting.

Leukotrienes —————
are lipid compounds derived from arachidonic acid that are involved in the
inflammatory response, particularly in conditions like asthma and allergies. They play a role in bronchoconstriction and the recruitment of immune cells.

Thromboxane—————
is another type of prostaglandin that
promotes blood clotting and constriction of blood vessels. It has the opposite effect of prostacyclins.

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32
Q

What are Trans fatty acids (TFAs)?

  1. What do they do?
  2. Most commonly used TFA?
A

Trans fatty acids are unsaturated (double bond) fatty acids that have a specific arrangement of their carbon-carbon double bonds.
- formed during hydrogenation(saturation) of natural oils

They are commonly found in processed foods (fast foods etc) and can have negative effects on health, such as increasing the risk of heart disease.

  1. They cause;
    •Systemic inflammation
    •Insulin resistance
    •Elevated LDL (bad lipoprotein)
    •Redued HDL (good lipoprotein)
  2. Margarine (substitute for butter)
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33
Q

What are simple and mixed triacyglycerols?

A

Triacylglycerols —- contain 3 fatty acids esterified to 1 glycerol

Simple
Same type of fatty acid on all 3 carbons of glycerol;
E.g
Tristeroyl glycerol or tristearin

mixed
2 or 3 different types of fatty acid on all 3 carbons of glycerol;

To C1 = saturated
To C2 = unsaturated
To C3 = can be either

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34
Q

Triglycerols of plants in general have higher content of ______ fatty acids compared to that of animals?

A

Unsaturated

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35
Q

What is saponification?

A

Saponification is a process in which fats or oils react with an alkali, such as sodium hydroxide, to produce soap and glycerol.
It is commonly used in soap-making.
-Hydrolysis of triacylglycerol by alkali

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36
Q

_____ fatty acids are more susceptible to rancidity?

  1. Hydrolytic rancidity occurs due to ?
  2. Oxidative rancidity occurs due to ?
A

1.Undaturated

  1. Partial hydrolysis of triacylglycerols by bacterial enzymes
  2. Oxidation of unsaturated fatty acids to;
    Decarboxylic acids
    Aldehydes
    Ketones
37
Q

1.Oxidative rancidity of fats and oils is prevented during commercial preparation by adding?

2.Antioxidabts for food preservation?

A
  1. Antioxidants
    Such as;
    •Tocopherols (vitamin E)
    •Hydroquinone
    •Gallic acid
    •a-napthol
  2. For preserving;
    •Propyl gallate
    •Butylated hydroxyToluene (BHT)
    •Butylated hydroxyanisole (BHA)
38
Q

Lipid undergo oxidation to produce ______ which can damage the tissue?

Can be prevented by?

A
  1. Peroxides & free radicals
    Free radicals cause;
    Aging
    Cancer
    Atherosclerosis
  2. Antoxidants such as;
    Vitamin E
    Urate
    Superoxide dimutase
39
Q

What is meant by Adulteration of oil?

A

Adulteration of oil refers to the act of adding impurities or lower-quality substances to oil. It can be done to increase profits or deceive consumers.

40
Q

What is saponification number?

Its value is higher for fats containing?

Saponification number for
Human fat
Butter
Coconut oil

A

The saponification number is a measure of the amount (mg) of potassium hydroxide (KOH) required to saponify a certain amount (1g) of fat or oil.

It helps determine the average molecular weight/size of the fatty acids present in the oil.

  1. Short chain fatty acids
  2. For;
    Human fat : 195-200
    Butter : 230-240
    Coconut oil 250-260
41
Q

What is iodine number?

A

The iodine number is a measure of the unsaturation or double bonds present in a fat or oil.
-Low iodine number—-less undaturation

It indicates the amount of iodine, in grams, that can react with (absorbed by) 100 grams of the (fat or) oil.

42
Q

What is Reichert-Meissl number?

RM range of butter and other edible oild?

A

The Reichert-Meissl number is a measure of the amount of volatile fatty acids present in a fat or oil.
- number of ml 0.1N KOH required to neutralize the soluble volatile Fatty acids distilled from 5g fat

-It helps determine the purity and quality of the fat or oil.

  1. Butter = 25-30
    Others= less than 1
43
Q

What is acid number?

A

The acid number is a measure of the amount of acidic substances present in a fat or oil.

-number of mg KOH required to completely neutralize the free Fatty acids in 1g fat fat or oil

It helps determine the degree of rancidity or deterioration of the fat or oil.

Refined oil should be free from free fatty acids

44
Q

Glycerophospholipid contain __________ esterified at its C__ & C__ with fatty acids?

Name 7 glycerophospholipids?

A
  1. Glycerol-6-phosphate
    . C1 & C2
  3. Phosphatidic acid
    (All other are derivatives of phosphatidic acid but with different nitrogenous bases)
  4. Lecithins (Phosphatidylcholine)
  5. Cephalin
    (Phosphatidylethanolamine)
  6. Phosphatidylserine
  7. Phosphatidylinositol
  8. Plasmalogins
  9. Cardiolipin
45
Q

Name the tests to check purity of fats & oils?

A
  1. Iodine number
  2. Saponification number
  3. Reichert-Meissl (RM) number
  4. Acid number
46
Q

Which is the simplest phospholipid? Importance?

  1. Which is the most abundant group of phospholipid in cell membranes?
A
  1. Phosphatidic acid
    (Intermediate in synthesis of triacylglycerol & phospholipids)
  2. Lecithin
    (Phosphatidylcholine)
47
Q
  1. Which nitrogenous base is present in lecithin?
  2. Lecithin is a derivative of?
  3. Lecithos means?
    4.What are the types of lecithin?
A

1.choline (stored in body form of phophatidyl choline)

  1. Phosphatidic acid
  2. Egg yolk
  3. 2 types;

(i)- Dipalmitoyl lecithin
-found in lungs
- acts as surfactant

(ii)- lysolecithin
- formed by removal of 1 fatty acid either at C1 or C2 of lecithin

48
Q
  1. Which nitrogenous base is present in Cephalin?
  2. Cephalin is a derivative of?
A
  1. Ethanolamine
  2. Phosphatidic acid
49
Q
  1. Which component is present in phosphatidylinositol (PI)?
  2. Phosphatidylinositol is a derivative of?
  3. Its importance?
A
  1. A sugar alcohol, stereoisomer myo-inositol is attached to phosphatidic acid to give PI
  2. Phosphatidic acid
  3. -Component of cell membrane
    - mediates actions of certain hormones (oxytocin, vasopressin)
50
Q
  1. Which component is present in phoshatidylserine?
  2. It is a derivative of?
  3. What is phosphatidylthreoine?
    Importance?
A
  1. An amino acid, serine
  2. Phosphatidic acid
  3. A glycerophospholipid, derivative of phosphatidic acid that;
    Contains amino acid, threonine
    - role in apoptosis
51
Q

1.What are plasmalogens?
Example?

  1. Which type of fatty acid occurs at C1?
A

Plasmalogens are a type of glycerophospholipids that contain a ether bond , to which a fatty acid attaches at the C-1 position of the glycerol backbone.
-E.g
Phosphatidalethanolamine

  1. Unsaturated
52
Q

What is the difference between phosphatidalethanolamine and phosphatidylethanolamine?

A

phosphatidalethanolamine
Has ether linkage
- it’s a plasmalogen

(Instead of ester like in
phosphatidylethanolamine)

53
Q

1.What is cardiolipin? Where is it found? Its function?

  1. It is isolated from?
  2. Its decreased level causes?
A

Cardiolipin is a unique phospholipid (glycerophospholipid) found in the inner mitochondrial membrane.

It plays a crucial role in maintaining mitochondrial structure and function, particularly in energy production.

  1. Heart muscle
  2. •Mitochondrial dysfunction
    •Hypothyroidism
    •Cardioskeletal myopathy
    (Weakness of heart & skeletal mucles) (Barth syndrome)
54
Q

What is Barth syndrome?

A

Barth syndrome is a rare genetic disorder that primarily affects males.

It is characterized by muscle weakness, cardiomyopathy (weakening of the heart muscle), growth delays, and low levels of certain white blood cells.

It is caused by mutations in the tafazzin gene, which plays a role in cardiolipin production.

This results in abnormal cardiolipin levels (low), affecting mitochondrial function and leading to the symptoms associated with Barth syndrome.

55
Q

The only glycerophosholipid or phosphoglyceride that possess antigenic properties?

A

Cardiolipin

56
Q

1.The amino alcohol present in sphingomeylins (sphingophospholipids)?

  1. Sphingosine is attached by a ______ link to a fatty acid to produce______?
  2. In its structure, alocohol group is bound to_______?

4 . Important constituents of?

A
  1. Sphingosine (no glycerol at all)
  2. Amide linkage
    Ceramide
  3. Phosphoryl choline
  4. Myelins
    (Brain, nerve tissue)
57
Q

Action of ceramide in sphinomyelins?

A

Acts as a second messenger (signaling molecule)
By regulating;
•Apoptosis
•Cell cycle
•Cell differentiation

A ceramide containing 30-carbon fatty acids is a component of skin & regulated skin’s water permeability

58
Q

Which phospholipids maintain cellular respiration & how?

A

lecithin
Cephalin
Cardiolipin

By maintaining conformation of ETC components

59
Q

Phospholipids are essential for synthesis of lipoproteins that are involved in?
2. Why phospholipis are regarded as lipotropic factors?

A

1.Transports of lipids

  1. Bcz prevent fatty liver (accumulation of fat in liver)
60
Q

Cephalin is an important group of phospholipids that participates in ?

A

blood clotting

61
Q

What are second messengers?

A

Second messengers are signaling molecules that transmit signals from the cell surface to the cell interior.

They play a crucial role in various cellular processes, such as
hormone signaling and neurotransmission.

Examples include cyclic AMP (cAMP) and calcium ions (Ca2+).

62
Q

Phosphatidylinositol phospholipid acts as source of which second messengers that are involved in the action of some harmone?

A

inositol triphosphate (ITP)
Diacylglyceol

63
Q

Infant respiratory distress syndrome?

A

Due to absence of lung surfactant

Caused by inability of immature lungs to synthesize dipalmitoyl lecithin

64
Q

What is the indicator of fetal maturity?

A

Lecithin/Sphingomyelin ratio (L/S) of the amniotic fluid

During early fetal growth (upto 28th week);
,Sphingomyelin >
Later;
Lecithin>

So L/S ratio above 2 —- full lung maturity

If <1—-IRDS

65
Q

Which complex lipids occur as cell surface carbohydrates to form glycocalyx in plasma membrane?

A

Glycolipids (glycosphingolipids)

66
Q
  1. Name the types of glycolipids?

2.Simplest & most important & complex form of glycolipids?

A
  1. •Cerebrosides
    •Gangliosides
    •Globosides

2.Simplest—- cerebrosides
- most imp of these;
• Galactocerebroside (galactosylceramide)
• Glucocerebroside

Complex—-gangliosides(derived from cerebrosides)

67
Q

What is the structure of cerebrosides?

The fatty acid in case of galactosylceramide?

  1. Derivative of galactosylceramide?
A
  • Ceramide (sphingosine attached to a fatty acid)
  • one or more sugar
  1. Cerebronic acid
  2. A sulfatide—- sulfagalactosylceramide
68
Q

Structure of gangliosides?

  1. Most important gangliosides??
  2. Which ganglioside accumulates in Tay-Sach’s disease?
A

1.- one or more molecules of N-acetylNeuraminic Acid (NANA) (–most imp sialic acid)
- carbohydrate attached to ceramide

  1. Imp are;
    GM1(mono- sialic acid )
    GM2
    GD (di- sialic acid)
    GT (tri- sialic acid)

-number donates carbohydrate sequence

  1. GM2
69
Q

What is Tay-Sachs disease?
Cause?

A

Tay-Sachs disease is a rare genetic disorder that affects the nervous system.

It is characterized by the progressive destruction of nerve cells in the brain and spinal cord.

Caused by
In Taysach disease, there is an abnormal accumulation of a fatty substance called GM2 ganglioside in the nerve cells.

70
Q

1.What are globosides?

2.Which globoside is present in erythrocyte membrane?

A
  1. A Type of glycosphingolipids (glycolipids)
    - 2 or more sugars linked to ceramide (fatty acid linked to sphingosine)
    Usually glucose & galactose
  2. Lactosylceramide (ceramide-galactose-glucose)
71
Q

1._______ acts as transport vehicles for lipids?

  1. Name their 5 types.
A
  1. Lipoproteins
  2. •Chylomicrons
    •Very low density lipoprotein (VLDL)
    •low density lipoprotein (LDL)
    •High density lipoprotein (HDL)
    •Free fatty acid-albumin complexes
72
Q

What are good and bad lipoproteins?

A

Good lipoproteins
, such as :
high-density lipoprotein (HDL),
help transport cholesterol from the body’s tissues to the liver for removal.

Bad lipoproteins
, like;
low-density lipoprotein (LDL),
can contribute to the buildup of cholesterol in the arteries.

73
Q

1.Steroid contain _____ steroid nucleus? Namely?

2.What are the rings?

3.What type of lipids are steroid?

  1. Name some steroids?
A
  1. Cyclic or ring
    Cyclopentanoperhydrophenanthrene (CPPP)
  2. It consists of;
    Phenanthrene nucleus
    (Ring A,B,C)
    To which a
    Cyclopentane ring is attached
    (Ring D)
  3. These are the derived lipids

4.
• Cholesterol
•Bile acids
•Vitamin D
•Sex hormones
•Adrenocortical hormones
•Sitosterols
•Cardiac glycosides
•Alkaloids

74
Q

Important peculiar points eelated to vitamin C And D?

A

Vitamin C
the structure of vitamin C resemble monosaccharides.
It has a similar ring structure like glucose and fructose.
(But it is NOT a carbohydrate)

Vitamin D
the structure of vitamin D does resemble steroids. It shares a similar four-ring structure found in steroids.
(It IS a steroid)

75
Q

1.What is a sterol?

  1. In steroid,
    Methyl side chains are? And attached to carbon?
    And a side chain is present at which carbon?
A

1.If a steroid contains one or more hydroxyl groups
—- sterol (solid alcohol**

2.Methyl side chains — 19 & 18
And attached to carbon— 10 & 13
And side chain at carbon—17

76
Q

1.The most abundant animal sterol?

  1. First isolated from?
  2. Literally mean?
A

1.Cholesterol

  1. Bile
  2. Solid alcohol from bile
77
Q

1.What is the structural formula of cholesterol?

  1. It has hydroxyl groups at?
    And double bonds at?
  2. What type of side chain is attached to cholesterol and at which?
  3. Contains how many methyl groups?
A
  1. C27H46O
  2. 1 hydroxyl group at C3
    & 1 double bond btw C5 & C6
  3. 8 carbon aliphatic side chain at C17
  4. Total of 5 methyl groups
78
Q

1.What is meant by ‘cholesterol is ampiphilic’? & why?

  1. Occurence is much higher in?
  2. Cholesterol with fatty acids form?
  3. Physical appearance?
A
  • due to -OH group

Cholesterol is amphiphilic, which means it has both hydrophilic (water-loving) and hydrophobic (water-repelling) regions. This allows it to interact with both water and lipid molecules in the body.

  1. Sub-cellular organellez
  2. Cholesteryl esters
    (Esterification occurs with OH group at C3)
  3. Yellowish crystalline solid (notched)
79
Q

What are polyprenoids?

  1. How they related to cholesterol?
  2. Some examples ?
  3. Are these steroids?
A

Polyprenoids are a group of compounds that are derived from isoprene units.
They are found in various organisms, including plants and animals.

Polyprenoids play important roles in biological processes such as membrane structure and function, as well as serving as precursors for the synthesis of molecules like vitamins and hormones.

  1. Both derived from isoprene units
  2. •Ubiquinone (coenzyme Q) of ETC ( not to be confused with ubiquitin—-marker protein for degradation)
    •Dolichol—- glycoprotein synthesis
    •Plant derived polyprenoids
    Vitamins A,D,E,K & Provitamin A (B-carotene)
    Camphor
    Rubber
  3. NO!!! NOT STEROIDS
80
Q

What is ergosterol?
Importance?

  1. What are other sterols present in plants?
A

Ergosterol is a type of sterol found in fungi, yeast & plants.

Important precursor of vitamin D
When exposed to light—–ring of ergosterol opens—- convert to ergocalciferol( a compound containing vitamin D activity)

  1. Stigmasterol
    B-sitosterol
81
Q

1.What are amphiphatic lipids?
2. Examples?

A

Contain both hydrophobic & hydrophilic groups

  1. Among lipids are;
    •Fatty acids (hydrophilic head— COO- & hydrophobic tail—hydrocarbon chain)
    •Phospholipids
    •Sphingolipids
    •Bile salts
    •Cholesterol
82
Q

1.What are miscelles?

  1. In lipid bilayers, arrangement?
A

Micelles are small aggregates or clusters of molecules(such as amphiphatic lipids) that form in a solution.
They are formed when certain molecules, such as surfactants, gather together in a specific arrangement.
Micelles have a unique structure where the hydrophobic (water-repellent) parts (tail)of the molecules are shielded on the inside, while the hydrophilic (water-attracting) parts (head) face outward(aqueous phase), interacting with the surrounding solvent.
This arrangement allows micelles to solubilize and transport hydrophobic substances in aqueous solutions

  1. Polar head— outer aqueous phase
    Non-polar tail— interior
83
Q

How bile salts help in lipid digestion & absorption?

A
  • by miscelle formation

Micelle formation of bile salts refers to the process in which bile salts, which are amphipathic molecules, arrange themselves into micelles in the presence of water.
The hydrophobic portions of the bile salts come together and form the core of the micelle, while the hydrophilic portions face outward and interact with the surrounding water.
This allows bile salts to efficiently emulsify dietary fats, aiding in their digestion and absorption in the intestines.

84
Q

What is emulsification?

What are emulsions?

A

Emulsification is the process of breaking down and dispersing fat molecules into smaller droplets in a watery environment.
This is achieved by using emulsifiers, such as bile salts, which help mix the fat with water and prevent it from separating.

Emulsification increases the surface area of the fat, making it easier for digestive enzymes to break it down and for the body to absorb the nutrients.

2.Emulsions are mixtures of two immiscible liquids, such as oil (or non-polar triacylglycerol) and water, stabilized with an emulsifier.(usually amphiphatic lipids e.g bile salts, phospholipids)
They consist of tiny droplets of one liquid dispersed throughout the other.

85
Q

What are liposomes?
Importance?
Produced when? By which process?

A
  • microscopic vesicles made of lipid bilayer
  1. Act as carriers of drugs to target tissues
  2. When amphiphatic lipids in aqueous media are subjected to sonification
    (A process that uses high frequency sound waves to create small bubbles in liquid.
    So when lipids are added to liquid these bubbles encapsulate the lipids to form liposomes)
86
Q

The reactions given by cholesterol for identification?

Why cholesterol is a poor conductor of electricity?

Cholesterol plays roles in synthesis of?

Reverse transport of cholesterol is done by?

A

1.
•Salkowski test
•Liebermann-Burchard reaction
•Zak’s test

  1. Bcz has high dielectric constant
  2. Bile acids
    Hormones (sex & cortical)
    Vitamin D
  3. Phospholipids
87
Q

What is Antiphospholipid antibody syndrome?

Which phospholipid is targeted?
And why?

A

Antiphospholipid antibody syndrome is a condition characterized by the presence of specific antibodies that target phospholipids namely, Cardiolipin, which are a type of lipid found in cell membranes.
These antibodies can lead to an increased risk of blood clots forming in the arteries and veins, as well as pregnancy complications such as miscarriages
Eclampsia( serious condition that can occur during pregnancy, —- seizures or convulsions. It is usually associated with high blood pressure and can be life-threatening if not treated promptly.)
or preterm births.

  • patients with autoimmune diseases are more susceptible
  1. Mainly Cardiolipin
    Cardiolipin can act as an antigen because it is a phospholipid present in the inner mitochondrial membrane.
    When the immune system mistakenly recognizes cardiolipin as foreign, it triggers the production of antibodies leading to the formation of antiphospholipid antibodies.
88
Q

______ are the synthetic cleansing agents. E.g?

A

Detergents
E.g
Sodium lauryl sulfate

Biochemistry (11 decks)

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