Week 5

Question 1

Oxidation of ___ fatty acids to acetyl-CoA provides as much as ___% of energetic needs under all physiological circumstances. The ____ removed from fatty acids during oxidation pass through the __ __, driving ___ synthesis. The acetyl-CoA produced from the fatty acids may be completed oxidized to ___ in the citric acid cycle, resulting in further energy conservation

Answer 1

long-chain, 80, electrons, respiratory chain, ATP, CO2

Question 2

Triacylglycerols have long akyl chains that are essentially ______, highly reduced structures with an energy of ___ ___ (-38kj/mol). They are also _____ in water and aggregate in lipid ____, which does not raise the ____ of the cytosol and are ____. They can also be stored in large quantities in cells without the risk of undesired chemical reactions due to relative ____ ____

Answer 2

hydrocarbons, complete oxidation, droplets, osmolarity, unsolvated, chemical inertness

Question 3

However, because they are insoluble in water, triacylglyercols must be ____ before they can be digested by ___ ___ in the intestine. Those that are absorbed by the intestine must be carried in the blood bound to ___ that counteract their insolubility.

Answer 3

emulsified, water-soluble proteins, proteins

Question 4

To overcome the relative stability of the ___ bonds in a fatty acid, the carboxyl group at ___ is activated by attachment to _____ ___, which allows stepwise oxidation of the fatty acyl group at the ___ or ___ position.

Answer 4

C-C, C1, coenzyme A, C3, beta

Question 5

Vertebrates obtain fats in the ___, mobilize fats stored in ___ tissue, and in the liver, convert excess dietary ___ to fats for export to other tissues. During starvation, they can recycle lipids by ____. Triacylglycerols provide more than __ of the energy requirements of the ____, liver, and resting __ ___.

Answer 5

diet, adipose, carbohydrates, autophagy, half, heart, skeletal muscle

Question 6

In vertebrates, before ingested triacylgylcerols can be absorbed through the ___ ___ they must be converted from insoluble __ ___ particles to finely dispersed microscopic ____. This is carried out by ____ ____ such as ___ ___, which are synthesized from ____ in the liver, stored in the ____, and released into the ___ ___ after ingestion of a fatty meal

Answer 6

intestinal wall, macroscopic fat, miscelles, bile salts, taurocholic acid, cholesterol, gallbladder, small intestine

Question 7

Bile salts are ___ compounds that act as biological _____, emulsifying dietary fats into mixed micelles of bile salts and ____.

Answer 7

amphipathic, detergents, triacylgylcerols

Question 8

Micelle formation enormously increases the fraction of ___ molecules accessible to the action of _____ ____ in the intestine.

Answer 8

lipid, water-soluble lipases

Question 9

Lipase action converts triacylgylcerols to _____, and _____ and free ___ ___.

Answer 9

monoacylgylcerols, diacylgylcerols

Question 10

the products of lipase actions ___ or are transported into ____ _____ lining the intestinal surface, where they are reconverted to ____ and packaged with dietary ___ and specific ______, designating the protein into lipoprotein aggregates called ____.

Answer 10

diffuse, epithelial cells, triacylgylercols, cholesterol, apolipoproteins, chylomicrons

Question 11

Protein ____ target triacylgylcerols, phospholipids, cholesterol and ___ ___ for transport between organs.

Answer 11

moieties, cholesteryl esters

Question 12

Apolipoproteins combine with lipids to form several classes of ___ ___, spherical aggregates with ___ lipids at the core and ___ protein __ ___ and lipid ___ ___ at the surface. Various combinations of lipid and protein produce particles of different _____ ranging from chylomicrons and ____ to ______. These particles can be separated by _____

Answer 12

lipoprotein particles, hydrophobic, hydrophilic, side chains, head groups, densities VLDL, VHDL, ultracentriguation

Question 13

the primary protein component of chylomicrons

Answer 13

apolipoprotein B-48

Question 14

In lipid uptake from the intestine, chylomicrons move from the ___ ___ into the ___ ___ and then enter the ___ where they can exchange _____ with other types of circulating ___.

Answer 14

intestinal mucosa, lymphatic system, blood, apolipoproteins, lipoprotein

Question 15

In the blood chylomicrons pick up ______ ____ from ____ particles and are carried to muscle and ___ tissue. In the capillaries of these tissues, the extracellular enzyme __ ___, which is activated by the apolipoprotein picked up, ___ ___ to free fatty acids and ____.

Answer 15

apolipoprotein C-II, HDL, adipose, lipoprotein lipase, hydrolyzes triacylgylcerols, monoacylgylercols

Question 16

The fatty acids and monoacylgylcerols are taken up by specific ___ in the ___ ____ of cells in the target tissues. In muscle, the fatty acids are ____ for energy. In adipose tissue, they are ___ for storage as triacylgylcerols

Answer 16

transporters, plasma membrane, oxidized, reesterified

Question 17

The remnants of chylomicrons depleted in ___ but still containing __ and ___, travel in the blood to the ___ where they are taken up by _____, where they are taken up by ____ mediated by receptors for their apolipoproteins. Triacylglycerols that enter the liver by this route may be ___ to provide energy or to provide precursors for the synthesis of __ ____

Answer 17

triacylglycerols, cholesterol, apolipoproteins, liver, endocytosis, oxidized, ketone bodies

Question 18

When diet contains more fatty acids than are needed immediately for ___ or as ___, the liver converts them to ___ which are packaged with specific apolipoproteins into ______. These are secreted by ___ and transported in the blood to ___ tissue where the triacylgylcerols are removed and stored in lipid droplets within ___

Answer 18

fuel, precursors, triacylgylcerols, VLDLs, hepatocytes, adipose, adipocytes

Question 19

Netural lipids are stored in _____ in lipid droplets, which have a core of ___ and ___ ____ surrounded a monolayer of ___. The surface of these droplets is coated with ___, a family of proteins that restrict access to lipid droplets, preventing untimely lipid ____.

Answer 19

adipocytes, triacylgylcerols, sterol esters, phospholipids, perilipins, mobilization

Question 20

___ and ___ are secreted in response to low blood glucose levels or a ____ situation. They stimulate __ ___ in the adipocyte plasma membrane which produces _____. This will activate ____ which trigger changes that open the lipid droplet. 3 cytosolic ____ will act on tri, di and monoacylgylcerols, releasing __ __ and ___.

Answer 20

epinephrine, glucagon, fight-or-flight, adenylyl cyclase, cAMP, PKA, lipases, fatty acids, glycerol

Question 21

The released fatty acids pass from the adipocyte into the __ where they bind to protein __ ____. This protein ___ binds as many as ___ fatty acids. Bound to this ____ protein, the otherwise insoluble fatty acids are carried to tissues, where they ___ from the protein and are moved by plasma membrane ____ into cells to serve as fuel

Answer 21

blood, serum albumin, noncovalently, 7, soluble, dissociate, transporters

Question 22

The glycerol released from lipase action is phosphorylated by __ ___. The resulting ____ is oxidized to ____ ____. The glycolytic enzyme ____ ___ ____ converts this compound to _____ which is oxidized via glycolysis

Answer 22

glycerol kinase, glycerol 3-phosphate, dihydroacetone phosphate, triose phosphate isomerase, glyceraldehyde 3-phosphate

Question 23

Short and medium chain fatty acids those with chain lengths of ___ or fewer carbons, enter the mitochondria without the help of membrane transporters. Long chains with -__ or more carbons, must be transported through the ___ __

Answer 23

12, 14, carnitine shuttle

Question 24

first the fatty acid must be activated by a ___ ___ ___ isozymes specific for long-chain fatty acids. The isozymes are present in the ___ __ ___, and catalyze the formation of a ____ ___ between the fatty acid ___ group and the thiol group of __ __ to yield a ___ ____. This is coupled to the cleavage of ___ to AMP and PPi

Answer 24

fatty acyl-CoA synthetase, outer mitochondrial membrane, thioester linkage, carboxyl, coenzyme A, fatty acyl-CoA, ATP

Question 25

Fatty acyl-CoA esters formed on the cytosolic side of the outer mitochondrial membrane can be transported into the mitochondria via attachment to _____, and oxidized to produce _____, or they can be used in the cytosol to synthesize __ ___.

Answer 25

carnitine, ATP, membrane lipids