Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochem( (Lipids Digestio) > 1-20 slides > Flashcards

1-20 slides Flashcards

1
Q

What is the primary enzyme involved in lipid digestion in the mouth?

A

Lingual lipase

Lingual lipase is particularly important in infants for the digestion of milk fat.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which gland is responsible for secreting lingual lipase?

A

Von Ebner’s gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the main digestion product of triacylglycerols (TAG) in the stomach?

A

MAG + FA (Monoacylglycerol and Free Fatty Acids)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What percentage of triacylglycerol digestion occurs in the stomach?

A

30%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

List the two main processes that aid lipid digestion in the small intestine.

A
  • Emulsification
  • Action of lipase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the role of bile salts in lipid digestion?

A
  • Emulsification
  • Stabilizes the emulsion
  • Provides alkaline medium
  • Helps in absorption
  • Produces surfactants
  • Potent choleretics
  • Excretes the waste
  • Solubilizes cholesterol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What enzyme catalyzes the hydrolysis of triacylglycerols at the C1 and C3 positions?

A

Pancreatic lipase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What protein helps bind water-soluble lipase to lipid substrates?

A

Colipase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens when there is inadequate production of bile salts?

A

Steatorrhea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which phospholipase is the major enzyme for dietary phospholipid digestion?

A

Phospholipase A2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the main type of lipid that is insoluble in water but soluble in organic solvents?

A

Lipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Fill in the blank: The most abundant bile salts are _______ and _______.

A

Taurocholate, glycocholate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the main transport form of dietary TAG?

A

Chylomicrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the main protein component of chylomicrons?

A

Apoprotein B-48 (apo B-48)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How are chylomicrons formed?

A

Synthesized in the ER of intestinal cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the function of lipoprotein lipase?

A

Hydrolyzes TAGs of chylomicrons and VLDL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are remnants of chylomicrons rich in?

A

Cholesterol esters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the classes of lipoproteins? List them.

A
  • Chylomicrons
  • Very low-density lipoproteins (VLDL)
  • Intermediate density lipoproteins (IDL)
  • Low-density lipoproteins (LDL)
  • High-density lipoproteins (HDL)
  • Albumin-free fatty acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the fate of intermediate density lipoproteins (IDL)?

A
  • Some are taken by the liver
  • Others are degraded to low-density lipoproteins (LDL)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What percentage of cholesterol do LDL contain?

A

About 50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

True or False: LDL receptors are localized in specialized regions called coated pits.

A

True

22
Q

What is the primary source of dietary cholesterol?

A

Une sterified cholesterol

23
Q

What is the process by which lipid absorption occurs in the intestine?

A

Passive diffusion

24
Q

What are micelles composed of for lipid absorption?

A
  • 2-monoacylglycerols
  • Fatty acids
  • Lysophosphoglycerides
  • Free cholesterol
25
Q

What happens to fatty acids in intestinal cells after absorption?

A

Converted to fatty acyl CoA molecules

26
Q

Fill in the blank: The first reaction in triacylglycerol formation is catalyzed by _______.

A

Monoacylglycerol acyltransferase

27
Q

What are the two main sources of lipids?

A
  • Exogenous sources (dietary)
  • Endogenous sources (synthesized in the body)
28
Q

What is the function of liver lipase?

A

Enzyme that hydrolyzes triacylglycerols in the liver

Liver lipase plays a key role in lipid metabolism.

29
Q

Where are LDL receptors localized?

A

In specialized regions called coated pits

Coated pits contain clathrin, a specialized protein.

30
Q

What binds to the LDL receptor on the cell surface?

A

Apo B-100

Apo B-100 is a protein on LDL that facilitates receptor binding.

31
Q

How does the receptor-LDL complex enter the cell?

A

By endocytosis

This process involves the formation of an endocytic vesicle.

32
Q

What happens to the endocytic vesicle after it is formed?

A

It fuses with lysosomes

Lysosomes contain enzymes that degrade LDL.

33
Q

What are the products of LDL degradation?

A

Free cholesterol and fatty acids

Cholesteryl esters are hydrolyzed to yield these products.

34
Q

What enzyme is responsible for reesterifying free cholesterol?

A

Acyl CoA:cholesterol acyltransferase (ACAT)

This enzyme converts free cholesterol back into cholesteryl esters for storage.

35
Q

What effect does increased intracellular cholesterol have on LDL receptors?

A

It suppresses the synthesis of LDL receptors

This feedback regulation limits further cholesterol uptake.

36
Q

What is the LDL/HDL ratio used for?

A

To evaluate susceptibility to atherosclerosis

A lower ratio indicates better cardiovascular health.

37
Q

What is the ideal LDL/HDL ratio for a healthy person?

A

Under 2.0

Ratios above this threshold indicate increased health risks.

38
Q

How are triacylglycerols delivered to adipose tissue?

A

In the form of chylomicrons and VLDL

These lipoproteins transport dietary fats in the bloodstream.

39
Q

What stimulates the hydrolysis of triacylglycerols during fasting?

A

Epinephrine, norepinephrine, glucagon, and adrenocorticotropic hormone

These hormones promote lipolysis to release energy stores.

40
Q

What is lipolysis?

A

Hydrolysis of triacylglycerols by lipases

It converts stored fats into free fatty acids and glycerol.

41
Q

What are lacteals?

A

The lymphatic vessels of the small intestine that absorb digested fats

They play a crucial role in lipid absorption.

42
Q

What is steatorrhea?

A

A clinical condition where there is excess fat in feces

It may indicate malabsorption issues.

43
Q

What is the primary energetic role of lipids?

A

Fuel molecules

Lipids serve as a major energy source for the body.

44
Q

What is celiac disease?

A

An autoimmune condition that damages the lining of the small intestine

It is triggered by the ingestion of gluten.

45
Q

What lipid is produced by the esterification of natural fatty acids with sucrose?

A

Olestra

Olestra is a non-absorbable fat substitute used in food products.

46
Q

What is Orlistat’s mechanism of action?

A

It inhibits pancreatic lipase, blocking lipid absorption

This results in increased lipid excretion.

47
Q

What are the three main types of dietary lipids?

A
  • Triacylglycerols
  • Phospholipids
  • Cholesterol

These are the primary lipid classes found in the diet.

48
Q

What is the primary storage form of energy in the body?

A

Triacylglycerols (TAGs)

They are more efficient energy stores compared to glycogen.

49
Q

What is the role of bile in lipid digestion?

A

Emulsifies fats to increase the surface area for enzymes

This process aids in the digestion of dietary lipids.

50
Q

What happens to glycogen reserves after eating?

A

They are depleted within 12 to 24 hours

In contrast, triacylglycerol reserves can last for several weeks.

51
Q

What is the process of digestion?

A

Conversion of complex lipid food molecules to simple absorbable forms

This is essential for nutrient absorption.

52
Q

What are the two major forms of stored energy in the body?

A
  • Triacylglycerols
  • Glycogen

Both serve as energy reserves but differ in storage efficiency.

Biochem( (Lipids Digestio) (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions