LIPIDS 2

52問 • 1年前

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are organic molecules that are long-chained carboxylic acids with 4-36 carbon atoms.

Fatty acids

The hydrocarbon chains are either saturated or unsaturated, depending on the bonds between the carbon atoms. If all the carbon-carbon bonds are single, the acid is ______; if one or more carbon-carbon double bonds are present, the acid is _______.

saturated; unsaturated

Naturally occurring fatty acids are mostly unbranched, and these occur in three main classes of lipids; _________

triglycerides, phospholipids, and cholesteryl esters.

Fatty acids are not found in the free state but remain associated with alcohol to form ________

triglycerides

Fatty acids are stored as an energy reserve (fat) through an ester linkage to glycerol to form ______.

triglycerides

are the simplest form of fats that are unbranched linear chains of CH2 groups linked together by carbon-carbon single bonds with a terminal carboxylic acid.

Saturated fatty acids

The term ‘_______’ is used to indicate that the maximum number of hydrogen atoms are bonded to each carbon atom in a molecule of fat.

saturated

The general formula for these acids is

CnH2n+1COOH.

Fatty acids obtained from an ______ are mostly even-numbered linear chains of saturated fatty acids.

animal source

Saturated fatty acids usually have a ________ than their counterparts which is why saturated fatty acids remain in the solid-state at room temperatures.

higher melting point

Saturated fatty acids are mostly solid and are found in animal fat like ________. But some saturated fatty acids are also found in vegetable sources like ________

butter, meat, and whole milk; vegetable oil, coconut oil, and peanut oil.

are more complex fatty acids with bent hydrocarbon chains linked together by one or more carbon-carbon double bonds with a terminal carboxylic acids group.

Unsaturated fatty acids

The term ‘_______’ indicates that the carbons atoms do not have the maximum possible hydrogen atoms bound to carbon atoms.

unsaturated

Due to the presence of double bonds, the cis and trans conformation of these molecules are important. The unsaturated fatty acids found in the human body exist in the _______

cis conformation

Unsaturated fatty acids have a ________ as compared to saturated fatty acids, and thus they exist in the liquid state at room temperatures

lower melting point

Most ________ are some of the important sources of unsaturated fatty acids

vegetable oils and fish oils

is a simple organic compound in three hydroxyl groups that is a colorless, odorless, and viscous liquid.

Glycerol

Glycerol forms the backbone of many lipids that are termed

glycerides

(Glycerol-Lipids) The fat is later hydrolyzed into fatty acids and glycerol where the ______ provides energy to the body, whereas the ______ is converted into glucose.

fatty acid; glycerol

The reaction involved in the formation of ester bonds is termed as ________ where the free hydroxyl end of the glycerol molecule joins to the OH of the COOH group of the fatty acid.

condensation reaction

The process of condensation is termed ______ due to the formation of ester bonds between the two molecules.

esterification

The lipid molecules formed from three fatty acids and a single glycerol molecule are termed as ______

triacylglycerols or triglycerides.

A ________ is an organic molecule consisting of fatty acids, a phosphate group, and a glycerol group that forms the main component of various cellular membranes.

phospholipid

________ forms an important part of the cell membrane for the selective transport of molecules in and out of the cell.

Phospholipid bilayer

The _________ forms the hydrophilic head, whereas the ________ form the hydrophobic tails. The head and tail regions in phospholipids are joined by a ______

phosphate group; fatty acids; glycerol molecule

The hydrophobic and hydrophilic interaction between different molecules and the lipid bilayer enables the passage of _______. These interactions make the cell membrane ______

biomolecules; amphipathic

The hydrophilic head or water-loving part of the phospholipids contains a _______ with an ________

negatively charged phosphate group; unidentified alkyl group

The hydrophilic region might or might not be polar or charged.

True

The heads of the phospholipid membrane face ______ that remain in interaction with the aqueous solution inside and outside the cell.

outwards

As water is a polar molecule, the hydrophilic head immediately forms _______ with the water molecule.

electrostatic interaction

The hydrophobic part of the phospholipid bilayer is also termed the water-fearing portion that consists of long ________

non-polar fatty acid tails

These _____ easily interact with other hydrophobic molecules but do not interact with water molecules.

tails

The _______ is a non-polar end where charge-less moleculesare present.

tail region

The hydrophobic tails are thus tucked towards the _______ of the membrane in order to shield the tails from the surrounding water. This arrangement is also _______

interior; energetically favorable.

The ____________ form a good barrier between the inside and outside of the cell as water, and other charge molecules cannot easily cross the hydrophobic core of the membrane.

hydrophobic interactions

are a type of lipids composed of steroid alcohols occurring naturally in plants, animals, fungi, and several bacteria.

Sterols

The most important and familiar type of sterol is _______ which plays an essential role in cell membrane structure and functions.

cholesterol

acts as a precursor to fat-soluble vitamins like Vitamin D and hormones.

Cholesterol

is formed of four linked hydrocarbon rings forming the bulk of the steroid structure.

Cholesterol

One end of cholesterol consists of a ______, whereas the other end is linked to an ______

hydrocarbon tail; alcohol group

Cholesterol can be ________ within the body of various animals.

biosynthesized

In humans, the ______ makes up 100% of all cholesterol required for the body

liver

Cholesterol is considered essential for the regulation of _______ in animals. It also increases the permeability of the cell membrane to sodium and potassium ions.

membrane fluidity

if the concentration of cholesterol increases beyond normal, it might combine with other components in the blood and form _____. This might attach to the walls of arteries and veins, resulting in _____

plaque; coronary artery disease.

are a chemically diverse group of compounds, and the biological functions of the lipids are as diverse as their chemistry.

Biological lipids

In the body, fats serve as an efficient source of energy and are also stored in the ______. These also serve as an insulating material in the ________ and around certain organs.

adipose tissues; subcutaneous tissues

are major structural elements of biological membranes

Phospholipids and sterols

are important constituents of the cell membranes and mitochondria of the cell.

lipoproteins

Lipids also act as the structural component of the cell and provide the ______ that allows the separation of the aqueous contents of the cell and subcellular structures.

hydrophobic barrier

Other lipids, although present in relatively small quantities, play crucial roles as _________ for proteins.

enzyme cofactors, electron carriers, light-absorbing pigments, and hydrophobic anchors

acts as a precursor to fat-soluble vitamins like Vitamin D and hormones.

Cholesterol

are also activators of enzymes like glucose-6-phosphatase, β-hydroxybutyric dehydrogenase, and stearyl CoA desaturase.

Lipids

CH 1

OBILLO, MIKAELA T. · 78問 · 1年前

CH 1