Brainscape's Knowledge GenomeTM

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


See full index

Biochem lecture > Test II-Leys > Flashcards

Test II-Leys Flashcards

1
Q

There are two major types of complex carbohydrates:

A

glycoproteins and proteoglycans.

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

Glycoproteins

A

are proteins that contain short glycan (or sugar) chains.

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

Glycan chains in glycoproteins

A

are usually about 3 to 15 sugars long and often highy branched. They do not have a repeating unit and usually contain about 10-15% carbohydrate by weight.

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

Glycoproteins are found on

A
  1. the cell surface proteins
  2. the ER
  3. the golgi
    or they are secreted.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Carbohydrates on glycoproteins:

A
  1. assist in protein folding to the correct conformation
  2. enhance protein solubility
  3. stabilize the protein against denaturation
  4. protect the protein from proteolytic degradation
  5. target the protein to specific subcellular locations
  6. serve as recognition signals for carbohydrate binding proteins (lectins).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The major sugar found in glycoproteins are:

A
  1. Amino sugars - N-acetylglucosamine and N-acetlygalactosamine
  2. Neutral sugars – galactose; mannose and fucose
  3. Acidic sugar - sialic acid (N-acetylneuraminic acid).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Proteoglycans contain as much as _____ sugars. Sugarchains are?

A

50-60%
usually long unbranched polymers than can contain hundreds of monosaccharides usually having a repeating disaccharide unit.

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

There are two types of linkages of carbohydrates to proteins.

A
  1. N – linked where the sugar is attached to an asparagine.
  2. O – linked where the sugar is attached to a serine; threonine or hydroxylysine.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

More than a 100 complex carbohydrate structures have been identified; each containing a core of

A

2 N-acetylglucosamines and 3 mannose residues.

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

Do many proteins have both N-linked and O-linked structures?

A

Hell yeah they do

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

There are ____ essential sugars

A

zero; cells can use glucose (or another common sugar) to make all other sugars needed.

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

Lectins on the surface of endothelial cells recognize _______.

A

carbohydrate signals on leukocytes

This is one example of interaction of different cell types through carbohydrates.

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

Complex carbohydrates are found on the surface of bacteria. Gram positive bacteria have a _________. Gram negative bacteria have_____.

A

Gram(+): a thick layer of peptidoglycan on their surface

Gram(-): a thin layer of peptidoglycan between two lipid bilayers.

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

The carbohydrate portion of peptidoglycan is made up of the

A

alternating co-polymers of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).

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

The synthesis and deposition of _____ is the target of several antibiotics including ______.

A

peptidoglycan

penicillin

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

Some bacteria are surround by a thick ______

A

polysaccharide capsule.

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

The ______ of _____ help bacteria stick to each other to form plaque on the surface of teeth.

A

glucans of S. mutans

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

Synthesis of biological compounds is called _____. Breakdown of compounds is ____.

A

anabolism
catabolism

*Remember cats never build; they only break down

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

______ is the main source of amino acids.

A

Dietary protein

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

There is no dedicated storage form of ______

A

amino acids.

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

Mammals acquire most of there energy from ____

A

carbohydrates + fats and proteins.

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

Carbohydrate breakdown is the _____ efficient but yields the ____ amount of energy.

A

most

lowest

23
Q

Protein releases _____ of energy however ___ byproduct must be eliminated.

A

an intermediate amount

nitrogen containing

24
Q

The liver functions:

A
  1. synthesizes nonessential amino acids
  2. removes and breaks down excess amino acids
  3. removes ammonia from the blood and converts it to urea
  4. makes other nitrogen-containing compounds.
25
Q

Amino acids feed into ____

A

other pathways (especially carbohydrate metabolizing pathways) at several locations including pyruvate and acetyl CoA and TCA intermediates.

26
Q

_____ can be converted to pyruvate and therefore glucose while___ cannot.

A

Amino acids

fatty acids

27
Q

The first step in converting amino acids into glucose or other intermediates is _____

A

deamination.

28
Q

The most common mechanism for deamination:

A

is transamination that exchanges the amino group with the keto group on alpha- keto glutarate resulting in glutamic acid.

29
Q

____ is a key intermediate in amino acid metabolism.

A

Glutamate

30
Q

Glutamate can be deaminated to give ___

A

free ammonia.

31
Q

There is loss or gain or no loss of nitrogen or ammonia during transamination?

A

no net loss

32
Q

Approximately ___ of the 20 amino acids that make proteins are essential or they are required in the diet. The other ___ are non-essential and we are able to synthesize them.

A

half

33
Q

The general scheme for amino acid catabolism is ____

A
  1. remove the amino group that is used to synthesize new nitrogen compounds or excreted as urea.
  2. incorporation of the carbon atoms into compounds that can enter the TCA cycle.
34
Q

Some of the major compounds that derive nitrogen from amino acids are:

A 
Nitric oxide
 hormones
 neurotransmitters
nicotinamide
heme
 creatin phosphate and nucleotides.
35
Q

Transaminase reactions are reversible or irreversible?

A

Reversible

This allows the inter-conversion between amino acids keeping their concentrations balanced.

36
Q

____ is highly toxic to living organisms and must be eliminated safely.

A

Ammonia

37
Q

Conversion of ammonia to urea takes place in the ___

A

liver.

38
Q

The urea cycle converts ________ into ______

A

one molecule of free ammonia (from glutamic acid) and one amino group from aspartate

urea and fumarate.

39
Q

There is a connection between the urea cycle and the TCA cycle through ____

A

the product of fumarate during the urea cycle.

40
Q

_____ is used to transport nitrogen from peripheral tissues to the liver.

A

Alanine

41
Q

In the liver alanine is converted to _____

A

pyruvate with the nitrogen incorporated into urea.

42
Q

This glucose-alanine cycle facilitates

A

that conversion of amino acids into glucose.

43
Q

______ account for about 50% of amino acids released by muscle into the blood.

A

Alanine and glutamine

44
Q

The conversion of ammonia into _______ occurs in the mitochondria.

A

carbamoyl phosphate

45
Q

Several genetic defects affect the urea cycle. A total lack of ______ is lethal.

A

urea cycle activity

46
Q

Treatment of lack of urea cycle activity?

A

can include the use of compound that react with amino groups and remove them from the body.

47
Q

Glucogenic amino acids are _____.

A

those that can be metabolized into 3 carbon molecules that can be used to synthesize glucose

48
Q

Ketogenic amino acids are ___

A

metabolized into 2 or 4 carbon structures.

49
Q

There are several ______ diseases caused by defects in amino acid metabolism. These include:

A

inherited

MSUD
Alkaptonuria (black urine)
Albinism
Phenylketonuria

50
Q

Phenylketonuria is ___

A

a deficiency of phenylalanine hydroxylase that converts phenylalanine to tyrosine.

51
Q

Maple syrup urine disease (MSUD) is _____

A

an inability to metabolize branch chain amino acids.

52
Q

Alkaptonuria (black urine disease) and Albinism are caused by other defects in ____ amino acid metabolism.

A

aromatic

53
Q

The first step in polyamine synthesis is______

A

the decarboxylation of ornithine to make putrescine.

54
Q

_________ is the rate-limiting step in ______ and has been the target for a number of cancer drugs.

A 
Ornithine decarboxylase (ODC)
polyamine synthesis

Biochem lecture (2 decks)

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