Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry > Carbohydrates Metabolism (Part 1) > Flashcards

Carbohydrates Metabolism (Part 1) Flashcards

1
Q

Carbohydrates …. of food

A

2/3 - (65-70%)

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

Monosaccharide

A

Glucose
Ribose
Fructose

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

Disaccharide

A

Lactose (Milk)
Sucrose (White sugar)
Maltose (Barley)

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

Polysaccharide

A

Starch (Bread - Rice)
Glycogen (Liver - meat)
Cellulose

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

Metabolism

A

All the chemical reactions that occur to the food stuff inside living cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

These substances is not metabolized

A

Vitamins , Minerals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Metabolism divide to

A

Anabolism :
- Required energy provided by cleavage of ATP into ADP or AMP
- For synthesis of PTN , CHO , lipids or their derivatives

Catabolism :
Involve oxidative processes that release energy (ATP)

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

CHO must be converted into …. to be absorbed

A

Monosaccharide

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

….. are chief CHO in our food

A

Starch, glycogen, sucrose, lactose, and cellulose

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

CHO hydrolyzed to ….. in GIT before they are absorbed

A

hexose sugar (glucose, fructose, and galactose)

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

Mouth enzymes

A

Salivary α – amylase (Ptylin)

pH : 6.7
Activation : Cl-

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

Stomach pH

A

2

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

Digestion action in mouth

A

Amylase hydrolyzes α-(1,4) glycosidic linkage

Starch , Glycogen , dextrin → Maltose , Glucose

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

Small intestine enzymes

A

Pancreatic α-amylase

pH : 7.1
Activation : Cl-

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

Digestion action in stomach

A

Stop due to its acidity inactivate salivary α – amylase

HCL → Hydrolyze dietary sucrose to glucose and
Fructose

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

Digestion action in small intestine

A
  • Pancreatic α-amylase
    hydrolyzes α-(1,4) glycosidic linkage
  • Intestinal enzymes (Disaccharidases)
    Lactase : Lactose → Glucose + Galactose
    Maltase : Maltose → Glucose + Glucose
    Sucrase : Sucrose → Glucose + Fructose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Intestinal enzymes

A

Disaccharidases

Lactase : Lactose → Glucose + Galactose
Maltase : Maltose → Glucose + Glucose
Sucrase : Sucrose → Glucose + Fructose

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

Lactose Intolerance

A

Inability to digest lactose due to deficiency of lactase enzyme which remain in intestines and get fermented by bacteria (Treated by milk lactose free)

May be congenital (Rare – Birthed with) or acquired (Common – Adult)

Symptoms:
1. Bloating , Abdominal cramps and pain due to ↑ CO2 produced by bacterial fermentation
2. Diarrhea due to increasing osmotic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Cellulose digestion in human

A

There is no β (1-4) glucosidase in human that can digest β (1-4) glycosidic bond between glucose molecules in cellulose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Congenital Lactose Intolerance

A

Complete absence or deficiency of enzyme

The child develop intolerance to lactose immediately after birth

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

Passive diffusion

A

Concentration gradient : Down the concentration gradient from high to low
Energy required : None
Protein carrier : Not required
Speed : Slowest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Active transport

A

Concentration gradient : Against concentration
gradient from low to high
Energy required : Required ATP
Protein carrier : Required
Speed : Fastest
E.g. : Glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Glucose transporter

A

Na+ dependent transporter
Na+ independent transporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Fate of the absorbed sugar

A
  1. Glucose is delivered to liver
  2. All other monosaccharides are converted to glucose in the liver
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Utilization by tissues

A
  1. Oxidation
  2. Storage
  3. Conversion to substances
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Complete oxidation of glucose

A

CO2 + H2O + Energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Oxidation Major pathways

A

Glycolysis , Krebs’ cycle and oxidative decarboxylation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Oxidation Minor pathways

A

Hexose monophosphate shunt and Uronic acid pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Sugar Storage

A
  • Glycogen in the liver and muscle (Limited)
  • Triacylglycerol in the adipose tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Conversion to substances

A

Galactose → Lactose , glycolipids & mucopolysaccharides synthesis

Fructose → Sperm sugar

Others : Amino sugar - Ripose - Fatty acid - Non essential a.a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Excretion of glucose in urine

A

Normally urine contains no glucose because the kidneys can reabsorb all the filtered glucose from the tubular fluid back into the bloodstream

When glucose blood level exceeds a certain limit (180 mg/dl) , it will pass to urine causing glucosuria

Normal range = 60 – 110 mg/dl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Glycolysis

A

Oxidation of glucose or glycogen to give
1. Pyruvate (in O2 presence)
2. Lactate (in O2 absence)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Glycolysis site

A

Cytoplasm of all tissue cells (Cytosol)

34
Q

Glycolysis has a physiological importance in …

A

RBCS and Muscles during exercise

35
Q

Uptake of Glucose by Cells

A
  • Glucose is freely permeable to Liver cells
  • Intestinal mucosa and kidney tubules, glucose is taken up by active transport
  • Skeletal muscle, cardiac muscle, insulin facilitates the uptake of glucose
36
Q

Glucose is freely permeable to …

A

Liver cells

37
Q

Glucose is actively absorbed in ….

A

Intestinal mucosa and kidney tubules

38
Q

The conversion of :
Glucose → Glucose 6 Phosphate

Needs … enzyme

A

Glucokinase or Hexokinase

39
Q

The conversion of :
Glucose 6 Phosphate → Fructose 6 Phosphate

Needs … enzyme

A

Phosphoglucose isomerase

40
Q

The conversion of :
Fructose 6 Phosphate → Fructose 1,6 Bisphosphate

Needs … enzyme

A

Phosphofructokinase “PFK-1”

41
Q

The conversion of :
Fructose 1,6 Bisphosphate → DHA-P , G3P

Needs … enzyme

A

Aldolase

42
Q

The conversion of :
DHA-P → G3P

Needs … enzyme

A

Triose phoshateisomerase

43
Q

The conversion of :
G3P → 1,3 Bisphosphoglycerate

Needs … enzyme

A

G3P Dehydrogenase

44
Q

The conversion of :
1,3 Bisphosphoglycerate → 3 Phosphoglycerate

Needs … enzyme

A

Kinase

45
Q

The conversion of :
3 Phosphoglycerate → 2 Phosphoglycerate

Needs … enzyme

A

Mutase

46
Q

The conversion of :
2 Phosphoglycerate → Phosphoenolpyruvate

Needs … enzyme

A

Enolase

47
Q

The conversion of :
Phosphoenolpyruvate → Pyruvate “ Pyruvic acid”

Needs … enzyme

A

Pyruvates

48
Q

Pyruvate “ Pyruvic acid” in aerobic conditions

A

Oxidation of 2NADH+H in mitochondria

49
Q

Pyruvate “ Pyruvic acid” in anaerobic conditions or RBCs

A

Remains within the cytoplasm and converts to lactate by the action of lactate dehydrogenase

50
Q

Fate of Blood lactate

A
  1. Conversion to pyruvate by LDH
  2. Lactate in liver can be converted to glucose or glycogen
  3. Lactate may be accumulated in muscle causing muscle fatigue
  4. Excretion in urine or sweat
51
Q

Hyperlactatemia

A

↑ blood lactate above normal level (5mg/dl)

Causes : physiological (severe muscular exercise) or pathological (anoxia)

Symptoms : Lacticacidosis , Coma

52
Q

Glycolysis Importance

A

Energy production
1. Under aerobic condition; glycolysis produces 8 ATP
2. Under anaerobic condition; glycolysis produces 2 ATP

Synthetic function
DHA-P can be converted to glycerol-3-phosphate for synthesis of Triacylglycerol and phospholipids

Importance of glycolysis in RBCs
1. Energy production: the only pathway that provide RBCs with ATP
2. Provides NADH for reduction of metHb (Hb + Fe+3) → Hb
3. 1,3 Bisphosphoglycerate is converted to 2,3 Bisphosphoglycerate which help release of 02 from Hb at tissues level

53
Q

…. can be converted to glycerol-3-phosphate for synthesis of Triacylglycerol and phospholipids

A

DHA-P

54
Q

DHA-P can be converted to …. for synthesis of Triacylglycerol and phospholipids

A

glycerol-3-phosphate

55
Q

DHA-P can be converted to glycerol-3-phosphate for synthesis of ….

A

Triacylglycerol and phospholipids

56
Q

Triacylglycerol and phospholipids synthesis needs .. enzyme

A

Triosephoshate isomerase

57
Q

Glycolysis regulation

A

Regulated by 3 irreversible enzymes :
1. Glucokinase or Hexokinase
2. Pyruvate kinase
3. PKF1 (main)

58
Q

PFK-1
(Main)

A

Activated by → AMP / ADP / F-6-P
Inhibited by → ATP

59
Q

Glucokinase

A

Site : Liver only
Substrate : Glucose only
Affinity : Few (High Glucose Conc.)
Act : After meal
Activators : Glucose
Inhibition : Fructose – 6 - p
Insulin : Increase activity
Glucagon : Decrease activity

60
Q

Hexokinase

A

Site : All tissues include liver
Substrate : Hexose but glucose mainly
Affinity : High (Low Glucose Conc.)
Act : Between meals
Activators : Glucose and other sugars
Inhibition : Glucose – 6 - p
Insulin : No effect
Glucagon : No effect

61
Q

Primary Acquired lactase deficiency

A

occur in adults due to defect in translation of RNA into enzyme

62
Q

Secondary Acquired lactase deficiency

A

occur at any age due to GIT disease or medication

Gastroenteritis due to rotavirus Intestinal parasite as giardia Chemotherapy

63
Q

CHO Site of absorption

A
  • Duodenum, upper jejunum (Mainly)
  • Very small amount is absorbed in the stomach or large intestine
64
Q

Facilitated diffusion

A

Concentration gradient :Down the concentration
gradient from high to low
Energy required : No
Protein carrier : Required
Speed : Fast
E.g. : Fructose

65
Q

Na+ dependent transporter

A

SGLT
Apical / Brush border

66
Q

Na+ independent transporter

A

GLUT
Base Border to transport to blood

67
Q

SGLUT 1

A

intestine and kidney

68
Q

SGLUT 2

A

Kidney to reabsorb

69
Q

SGLUT has 2 binding site

A
  • One for glucose and the other for Na
  • Na binding is important because after binding conformational changes occur in transporter so that glucose can bind
  • Na is transported & down the concentration gradient while glucose transported & against concentration gradient
  • ATP is required by Na-K ATPase pump to expel Na out
70
Q

… are down the concentration gradient from high to low

A

Na and glucose

71
Q

Why Expulsion of sodium is important ?

A
  1. Na is osmotically active causing osmotic flow to the cells leading to osmolysis
  2. Na concentration must be kept low to maintain downward gradient
  3. Na is inhibitory to many enzyme action
72
Q

GLUT 1

A

All cells with predominant in RBCs

Greatly affinity to glucose

73
Q

GLUT 2

A

In intestine , liver and pancreas

Transport glucose and fructose

74
Q

GLUT 3

A

All body mainly brain cells independent

75
Q

GLUT 4

A

Adipose tissue , Sk Muscle , Cardiac Muscle

Only transporter that under the effect of Insulin (High glucose level)

76
Q

GLUT 5

A

Luminal surface of intestine , Testicals , seminal vesicle

Greatly affinity to Fructose And low to glucose

77
Q

GLUT 6

A

Has no role uptake of glucose

78
Q

GLUT 7

A

Surface of Endoplasmic reticulum

79
Q

Factors affecting rate or monosaccharide absorption

A
  • The absorption is faster through intact mucosa
  • The absorption is decreased if there are inflammatory or injurious conditions in mucosa
  • Thyroid and mineralocorticoid increase glucose absorption
  • Vitamins B6, B12, B5 , folic acid required for glucose absorption
  • With advanced age, glucose absorption declines
  • Insulin has no role in absorption of glucose
80
Q

Cancer cells express high levels of …..

A

GLUT 1 to initialize more glucose which used as source of energy for highly divided cells

81
Q

Normal blood glucose level is ….

A

70-110 mg/dl

Biochemistry (6 decks)

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