Biochemistry chapter 5

Question 1

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Answer 1

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Question 3

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What are lipids ?

Answer 3

As a class they are characterized by insolubility in water and solubility in nonpolar organic solvents. Aside from this shared feature, they diverge dramatically in their structural organization and biological functions serving vital structural, signaling, and energy storage .

Question 4

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What is a amphipathic molecule?

Answer 4

A molecule that has both hydrophobic and hydrophilic region. For these membrane lipids, the polar head is the hydrophilic region, whereas the fatty acid are the hydrophobic regions.

Question 5

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What are phospholipids ? What are its elements ?

Answer 5

A family of lipids that are biological polymers. It contains a phosphate and alcohol that comprises the polar head group, joined to a hydrophobic fatty acid tail by phosphodiester linkages * One or more fatty acids are attached to a backbone to form the hydrophobic tail region {{2 2 0.png}}

Question 6

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What is a glycerol ? And what does it form ?

Answer 6

Its a three carbon alcohol It forms phosphoglycerides or glycerophospholipids and sphingolipids have a sphingosine( 18 carbon amino molecule with a unsaturated hydrocarbon chain which forms a primary part of sphingolipids which is a class of lipids as well) backbone

Question 7

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What are Sphingolipids ?

Answer 7

Molecules that have long chain non polar fatty acid tails and polar head groups. * Many of these sphingolipids also have phospholipids because they contain a phosphodiester linkage . Picture is below {{4 1 0.png}}

Question 8

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What is a glycolipid ?

Answer 8

Any lipid linked to a sugar

Question 9

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What are the four major subclasses from sphingolipids ? And what are they composed of?

Answer 9

Ceramide- which is a single hydrogen atom as its head group Sphingomyelins- are a major class of sphingolipids that are also phospholipids. These molecules have either phosphoatidylcholine or phosphotidyethanolamine Sphingosine (you should know this and what it is since you saw it on a previous flash card or you will know when you see it ) Glycosphingolipids - These are sphingolipids with head groups composed of sugars bound by glycosidic linkages are considered glycolipid. These are NOT phospholipids because they contain no phosphodiester linkage. They divide into Cerebroside and Ganglioside (you will know at the pic) {{6 1 0.png}}

Question 10

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Which components of membrane lipids contribute to their structural role in membranes ? Which component contributes to function ?

Answer 10

* Well the membrane lipids are amphipathic: they have hydrophilic heads and hydrophobic heads, allowing for the formation of blazers in aqueous solution. The fatty acid tails from the bulk of the phospholipids bilayer and play a predominantly structural role. * In function, these membrane lipids are determined by their polar head group due to its constant exposure to the exterior environment of the phospholipids bilayer ( remember this can be either the inside or outside of the cell). The degree of unsaturation of fatty acid tails can also play a small role in function.

Question 11

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What are two properties that determine how the overall molecule will behave ?

Answer 11

Fully saturated molecule – tails only have single bonds, when its bonded to four other atoms with no pi bonds. Like for example butter how its a solid in room temperature thanks to van deer wals force. An unsaturated fatty acid includes one or more double bonds. Double bonds that introduce kinks into the fatty acid chain which makes them difficult for them to stack and solidify.

Question 12

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What are Glycerphospholipids ? Phosphatidylcholine ? Also why are these membrane surface properties so important ?

Answer 12

Phospholipids that contain a glycerol backbone by ester linkages to two fatty acids and by a phosphodiester linkage to a highly polar head group. Phosphatidycholine —- The name of the glycerolphospholipid with a choline head group * They are important for cell recognition, signaling, and binding.

Question 13

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What would happen if an amphipathic molecule were placed in a nonpolar solvent rather than an aqueous solution ?

Answer 13

In a nonpolar solvent we would see the opposite of what happens in a polar solvent like water. The hydrophilic, polar part of the molecules would be sequestered inside, while the nonpolar, hydrophobic part of the molecule would be found on the exterior and exposed to the solvent.

Question 14

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What are three important categories of signaling lipids ?

Answer 14

* Steroids * Prostaglandins * Fat-soluble vitamins ; as well as important precursors like terpenes.

Question 15

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What are Terpenes ? How many equals a isoprene units ?

Answer 15

Class of lipids built from isoprene (C5H8) moieties. * They are produced mainly by plants and insects in which they have a strong scent. Some of these strong scents are a insects strong protective mechanism. * Teepees are also primary components of much more pleasant- smelling essential oils extracted from plants. One terpene= Two isoprene units {{12 1 0.png}}

Question 16

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What are Monoterpenes? Sesquiterpenes ? Diterpenes

Answer 16

* Contains two isoprene units ; abundant in both essential oils and turpentine * Contains three isoprene units * Contains 4 *remember its double the amount of isoprenes

Question 17

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What is the difference between Steroid and Steroid hormone ?

Answer 17

Steroid is just a metabolic derivative of terpenes. Its more structural if anything. They are nonpolar with their large number of carbons and hydrogen. Especially as they are four cycloalkane rings fused together : three cyclohexane and one cyclopentane. Steroid hormones on the other hand are secreted by the endocrine glands into the bloodstream and then travel on protein carries to distant sites, where they can bind to specific high-affinity receptors and alter gene expression levels. They regulate gene expression and metabolism such as testosterone, various estrogens, and aldosterone.

Question 18

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What are prostaglandins ?

Answer 18

A group of physiologically active lipid compounds having diverse hormone-like effects on animals. These are 20 carbon molecules are unsaturated carboxylic acids derived from araichidonic acid and contain one five carbon ring. {{15 0 0.png}}

Question 19

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What is a Vitamin ? And the fat soluble vitamins ?

Answer 19

An essential nutrient that can’t be adequately synthesized by the body and therefore must be consumed in the diet. Vitamins are commonly divided into water-soluble and lipid-soluble categories. * Fat soluble vitamins are Vitamins A,D,E,K

Question 20

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What is Vitamin A ? retinal ? Retinol ?

Answer 20

Or known as carotene is a unsaturated hydrocarbon that is important in vision, growth, and development and immune function. Retinal is a metabolite of Vitamin A in an aldehyde form that functions as light sensing for the eye. Retinol is the storage form of Vitamin A that’s oxidized into retinoic acid which is a hormone that regulates gene expression {{17 0 0.png}}

Question 21

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What is Vitamin D ? What happens when there is a lack in Vitamin D ?

Answer 21

Or known as cholecalcifereol can be consumed or formed in a UV-driven reaction in the skin. In the liver and kidneys this vitamin D is converted to calcitrol, the biologically active form of Vitamin D. Calcitrol increases calcium and phosphate reuptake in the intestines, which promotes bone production. Lack of Vitamin D can result in rickets , a condition seen in children and characterized by underdeveloped curved long bones as well as impeded growth.

Question 22

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What is Vitamin K ?

Answer 22

Its actually a group of compounds including phylloquinone (K1) and the menaquinones (K2) Vitamin K is vital to the posttranslational modification required to form prothrombin which is a clotting factor in the blood. The aromatic ring of Vitamin K undergoes a cycle of oxidation and reduction during the formation of prothrombin. * K is also required to introduce calcium binding sites on several calcium-dependent proteins. Mnemonic : Vitamin K is for Koagulation (when blood turns from liquid into gel in formation of blood clotting.

Question 23

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What is the difference between steroid and a steroid hormone (freebie question) ?

Answer 23

A steroid is defined by its structure; it includes three cyclohexane rings and a cyclopentane ring. A steroid hormone is a molecule within this class that also functions as a hormone, meaning it travels in the bloodstream, is active at low concentrations, has high affinity receptors, and affects gene expression and metabolism.

Question 24

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NSAIDS block prostaglandins production in order to reduce pain and inflammation. What do prostaglandins do to bring about these symptoms ?

Answer 24

They regulate the synthesis of cAMP, which is involved in many pathways, including those that drive pain and inflammation

Question 25

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What are Triacylglycerols ? Adipocytes ?

Answer 25

Also called triglycerides which is composed of three fatty acids bound by ester linkages to glycerol. * Special cells in animals that store large amounts of fat and are found primarily under the skin, around mammary glands and in the abdominal cavity. Especially in plants in which the triglycerides are found in seeds as oils. * This is why I need to lose weight because these triacylglyceols travel bidirectionally in the bloodstream between the liver and adipose tissue.

Question 26

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What is Saponification ?

Answer 26

This is the ester hydrolysis of triacyglycerols using a strong base which is used called lye the common name for sodium or potassium hydroxide. This results in the basic cleavage of the fatty acid, leaving the sodium salt of the fatty acid and glycerol. * This fatty acid salt is soap basically {{23 1 0.png}}

Question 27

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How does the human body store spare energy ? Why doesn’t the human body store most energy as sugar ?

Answer 27

The human body stores energy as glycogen and triacylglycerols. Triacylglycerols are preferred because their carbonate more reduced, resulting in a larger amount of energy yield per unit weight. In addition they have hydrophobic nature, triaglycerols do not need to carry extra weight from hydration

Question 28

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Describe the structure and function of triacylglycerols ?

Answer 28

Also known as triglycerides are composed of glycerol backbone esterified to three fatty acids used for energy storage.

Question 29

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Why does the soap appear to dissolve in water, and how is this fact important to cleaning ?

Answer 29

Soap appears to dissolve in water because amphipathic free fatty acid salts from Micelle, with hydrophobic fatty acid tails toward the center and carboxylate groups facing outward toward the water. Fat-soluble particles can then dissolve inside Michelle in the soap-water solution and wash away . Water-soluble compounds can freely dissolve in the water.

Question 30

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What are the effects of prostaglandins ?

Answer 30

* Powerful effects on smooth muscle function * Influence over sleep-wake cycle * Elevation of body temperature associated with fever and pain Nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin inhibit the enzyme cyclooxygenase (COX) which aids in the production of prostaglandins

Question 31

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What is a surfactant ? a colloid ? Micelle ?

Answer 31

It lowers the surface tension at the surface of a liquid, serving as a detergent or emulsifier. This is How soap works. * If we try to combine an aqueous solution and oil, as with vinegar and olive oil in salad dressing, these solutions remain in separate phases If we were to add a soap, however the two phases would appear to combine into a single phase forming a colloid. A colloid happens because of Micelles ( tiny aggregates of soap with hydrophobic tails turned inward and the hydrophilic heads turned outward, thereby shielding the hydrophobic lipid tails and allowing for overall salvation