Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

2.2 Clinical Chemistry > Plasma Proteins - Introduction and Methods of Analysis > Flashcards

Plasma Proteins - Introduction and Methods of Analysis Flashcards

1
Q

What percentage of whole blood is plasma

A

55%

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

What is plasma composed of?

A

Water (92%)

Proteins (4%)

Lipids (3%)

Other solutes (1%)

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

What proteins are found in plasma
(4)

A

60% albumin

35% globulins

4% fibrinogen

1% regulatory hormones

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

What does albumin do
(3)

A

Contributes to plasma osmotic pressure

Binds to hormones and inactivates them

Transports lipids

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

What do globulins do?

A

Transport ions, hormones, immune function

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

What does fibrinogen do

A

Essential component of clotting system

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

What are regulatory proteins

A

Enzymes and hormones

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

How many plasma proteins are there

A

150+

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

What is the range of sizes in plasma proteins

A

Between 21 kDa and 971 KDa

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

What is plasma vs serum

A

Plasma = anticoagulant added - contains all clotting proteins

Serum = allowed to clot - clotting removes many proteins especially fibrinogen so the total protein concentration will be lower

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

What is the role of plasma proteins
(4)

A

They are trapped in the vascular system -> cant fit in capillaries

They provide a colloidal osmotic pressure

They maintain normal blood volume

Maintain normal water load in interstitial fluid and tissues

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

What is the intracellular compartment

A

Consists of the fluid inside of cells

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

What is the extracellular compartment

A

Consists of the interstitial fluid and intravascular fluid (plasma)

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

How is total body water distributed

A

2/3 is in the intracellular fluid compartment
1/3 in the extracellular fluid compartment

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

What makes up extracellular fluid

A

75% interstitial fluid
25% intravascular fluid/plasma

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

What proteins are responsible for transport/binding

A

Albumin
Apolipoprotein
Haptoglobin
Thyroxine binding protein

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

What protein is responsible for oncotic pressure

A

Albumin

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

List some enzyme inhibitor proteins
(3)

A

Alpha-1-antitrypsin

Cystatin C

C 1-esterase inhibitor

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

List three immune defence proteins

A

Immunoglobulins

Complement

C-reactive protein

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

List three acute phase proteins

A

C-reactive protein

Alpha 1 acid-glycoprotein

Serum amyloid A (SAA)

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

List some proteins with enzymatic activity
(5)

A

Complement C3

Complement C4

Haptoglobin

Cerulopasmin (CER)

Alpha-1-antitrypsin

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

List some tissue derived proteins
(5)

A

Fibrinogen

Antithrombin

Coagulation factors

Proteins of the fibrinolysis process

Fibronectin

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

Where are most proteins synthesised

A

The liver

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

Where are gamma globulins synthesised

A

Synthesised and secreted by plasma cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Where are plasma proteins synthesised (3)
By the liver cells By endothelial cells By blood cells e.g. lymphocytes and plasma cells (immunoglobulins)
26
What influences protein synthesis (4)
Nutritional status Various feedback mechanisms Hormonal factors Genetic factors
27
How much albumin do you make a day
About 10g of albumin
28
Where does degradation of proteins occur (2)
Mainly in the liver Some proteins e.g. albumin are eliminated via the renal system
29
How are proteins broken down in the liver (3)
Proteins are endocytosed by hepatocytes Plasma proteins are then deglycosylated and then cleaved into amino acids by proteinases and peptidases This occurs in the lysosomes and cytosol of the cell
30
Where in hepatocytes does protein breakdown occur
Lysosomes and the cytosol
31
Describe protein homeostasis (2)
Synthesis of protein must be equal to protein catabolism i.e. protein production must equal protein loss
32
What affects protein concentrations in blood (2)
Abnormalities -> which arise from a wide variety of unrelated conditions Alterations in hydration which affect the concentration of proteins but not the absolute amount
33
List the most important groups of proteins (11)
Enzymes Polypeptide hormones Antibodies and complement components Plasma proteins Apolipoproteins Haemoglobin Protein coagulation factors Structural proteins Contractile proteins Storage proteins Chromosomal proteins
34
What is the main role of polypeptide hormones
They regulate metabolism
35
What is the main role of plasma proteins
Maintain oncotic pressure
36
Name three structural proteins
Keratin Collagen Elastin
37
Name a contractile protein
Myosin
38
Name a storage protein
Ferritin
39
Name a chromosomal protein
Basic histones
40
What is the equation for total plasma proteins
Albumin + globulins + fibrinogen
41
What is the equation for globulins
Total proteins-albumin = globulin level
42
Why do we measure total protein and globulins
They give us a general index of overall health and nutrition The globulins also contain antibodies
43
What is the albumin globulin ration and why do we measure it (2)
Serum albumin/ serum globulin g/l This ratio can help us identify disorders of serum proteins
44
What is the optimal albumin/globulin ratio
1.5 -> 2.2
45
List the 6 methods used to analyse total proteins
Kjedahl method Biuret reaction Dye binding reactions UV spectrophotometry Refractometry Turbidometric methods
46
What is the Kjedahl Method (5)
This measures nitrogen We assume that protein contains 16% nitrogen Any nitrogen containing compounds (proteins) in plasma are digested with sulphuric acid, a catalyst and a salt Ammonia is produced which is then distilled into a boric acid solution and titrated with acid Must then correct for non-protein nitrogen by analysing a protein free filtrate as well
47
What is the Biuret Reaction (2)
Most common method used to analyse protein It is an automated process in labs
48
What is the principle behind the Biuret reaction (3)
Copper reacts in an alkaline solution with peptide linkages to produce a violet coloured complex This can be measured used a spectrophotometer at absorbance 540 nm This detects all different types of proteins and is accurate for the range of 10-100g/l
49
What are the downfalls of the Biuret Reaction (2)
Need at least 2 peptide linkages -> will not detect free amino acids Not sensitive enough for low concentrations i.e. can't be used for CSF, urine and many body cavity effusions
50
What dye binding methods are used to analyse proteins (3)
Proteins can bind certain dyes resulting in a change of absorption spectrum Coomassie blue and pyrogallol red are typically used Different proteins bind different amounts of due therefore the colour change depends on the composition of the protein
51
What are the downfalls of dye binding methods to analyse proteins
Difficult to standardise for complex protein mixtures as each protein absorbs a different amount of dye Some dyes are specific e.g. bromocresol green for albumin
52
What dye is specifically used for albumin
Bromocresol green
53
How can UV spectrophotometry be used to analyse proteins (4)
Aromatic amino acids such as phenylalanine and tyrosine absorb light at 280nm Therefore abs 280 can be used to estimate protein composition e.g. 1g/L Albumin = Abs280 of 0.530 Therefore if your sample reads at 0.530 it contains 1g/L albumin By knowing the Molar absorptivity of a particular protein its concentration can be determined using Beers Law (A = ebc)
54
What are the downfalls of UV spectrophotometry to analyse protein (2)
Difficult to standardise for complex protein mixtures Only used for specific proteins such as albumin or IgG
55
Give two examples of aromatic amino acids
Phenylalanine and tyrosine
56
What is refractometry used for in the analysis of proteins
Used for estimating plasma protein (including fibrinogen) in EDTA plasma
57
What is the principle of refractometry (2)
Measure the refractive index of a sample relative to the refractive index of water The reading is a measurement of total solids and is only an estimate of protein concentration since there is variation in other serum components e.g. sodium, phosphate, glucose etc which can affect the refractive index as well
58
What is the main downfall of refractometry
Lipaemia and moderate to severe haemolysis renders the results invalid
59
What is the turbidometric method of analysing protein (2)
A sensitive method of quantifying protein in low-protein fluids such as CSF or urine Used when protein level is too low for biuret or refractometer method
60
What is the principle behind turbidometry
The process of measuring the loss of intensity of transmitted light due to the scattering effect of particles suspended in a sample
61
How sensitive is turbidometry
Sensitive to as little as 60 mg/L of protein

2.2 Clinical Chemistry (28 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions