Proteins Flashcards
The alpha keto-acid of alanine is:
a. Alpha-ketoglutarate
b. Pyruvate
c. Aspartate
d. Oxaloacetate
B. Pyruvate
Which of these amino acids has 2 nitrogens? Select one: a. Glutamine b. Isoleucine c. Leucine d. Glutamate
A. Glutamine
What happens to protein synthesis following resistance exercise? Select one: a. It is decreased b. It remains the same c. It depends on the time of day d. It is increased
d. It is increased
How much gross energy (kcal) is produced from the complete breakdown of protein? Select one: a. 4.2 b. 5.05 c. 5.65 d. 4.0
d. 4.0
Proteins are broken down in the Select one: a. Stomach, duodenum, ileum b. Mouth, stomach, duodenum c. Mouth, oesophagus, small intestine d. Stomach, duodenum, colon
a. Stomach, duodenum, ileum
Which of the following are a branched chain amino acids? Select one: a. Leucine and valine b. Isoleucine and glutamine c. Leucine and alanine d. Valine and alanine
a. Leucine and valine
Post translational modification refers to
Select one:
a. modification, translocation and activation of a
nascent protein
b. chromatin conjugation of a protein
c. amino acid excretion by kidneys
d. incorporation of proteins into the mitochondrial matrix
a. modification, translocation and activation of a
nascent protein
In normal healthy individuals body proteins can be excreted as Select one or more: a. sweat b. Skin c. Urine d. Hair
b. Skin
d. Hair
Protein synthesis accounts for what percentage of basal energy expenditure? Select one: a. 40 b. 50 c. 20 d. 10
c. 20
Which amino acid is always the first in a polypeptide chain? Select one: a. Methionine b. Alanine c. Leucine d. Glutamate
a. Methionine
Which of the following is not a step in protein synthesis Select one: a. Transcription b. Deamination c. Translation d. Post-translational modifications
b. Deamination
Select one:
a. 40S and 80S
b. 30S and 60S
c. 40S and 60S
d. 40S and 70S
c. 40S and 60S
Which proteolysis system is activated by calcium? Select one: a. Ubiquitin-proteosome b. Lysosomal c. Caspases d. Calpain
d. Calpain
Which protein breakdown system is predominantly involved in apoptosis? Select one: a. Calapain b. Caspases c. Matrix metalloproteinases d. Lysosomal
b. Caspases
What is the difference between essential and non-essential amino acids?
- Non- essential amino acids (NEAA) your body can make
* Essential amino acids (EAA) One you have to take in through the diet
Name the branched chain amino acids
Leucine, isoleucine and valine.
What are the three steps involved in protein synthesis; give a brief overview.
Transcription: copying of DNA to mRNA
Translation: Initiation/Elongation/termination: reading of mRNA to make polypeptide chain
Post translational modifications: folding into a useful structure
What is the immediate fate of excess dietary protein in the body?
Deamination
Which of the following leads to the production of urea?
a. Oxidation of glucose
b. Oxidation of amino acids
c. Incomplete oxidation of fatty acids
d. Synthesis of protein from amino acids
b. Oxidation of amino acids
What are positive and negative nitrogen balance? What can cause these states?
POSITIVE NITROGEN BALANCE Nitrogen intake greater than excretion. So, protein synthesis exceeds rate of breakdown. Causes: >during normal growth of children >in convalescence after serious illness >in immobilisation after an accident >in pregnancy
NEGATIVE NITROGEN BALANCE Nitrogen intake less than excretion. Causes: >starvation >during serious illness >in injury and trauma (including surgery) If not corrected and becomes prolonged, there will be irreversible loss of body tissue. Will ultimately lead to death.
How are amino acids broken down into a keto acid and an amino group?
Oxidative deamination:
>remove amino group
>amino group secreted as urea
>left with keto acid
Transamination
>converts one amino acid and keto acid into another amino acid and keto acid
>can also be used to make non-essential AAs
After deamination, the amino group is secreted as urea. What happens to the keto acid?
> can be metabolised by the TCA cycle to CO2 and H20, and provide a source of ATP
> glucogenic AAs can be converted into glucose by the liver
> ketogenic AAs (lysine and leucine) can be degraded to acetyl CoA, which can then either be converted into fatty acids, or can go into the TCA cycle
In which compounds is nitrogen transported to the liver for urea production?
Glutamine & alanine.
Where do the two amino groups in urea come from?
the two amino groups in urea come from?
One from NH4+, from deamination of glutamate (from transamination of any other AA).
One from aspartate, which can enter the urea cycle without being deaminated.
KWASHIORKOR
protein deficiency with adequate energy intake
>characterised by severe oedema
>enlarged liver, fat infiltration
MARASMUS
> caused by chronic food shortage
>extreme emaciation, loss of body’s fat reserves, muscle wasting, etc.
What is the ketoacid for oxaloacetate
a. Alpha-ketoglutarate
b. Pyruvate
c. Aspartate
d. Alanine
c. Aspartate
What is the ketoacid for glutamate
a. Alpha-ketoglutarate
b. Pyruvate
c. Aspartate
d. oxaloacetate
a. Alpha-ketoglutarate
What is the amino acid which matches alpha-ketoglutarate
a. glutamate
b. oxaloacetate
c. alanine
d. pyruvate
a. glutamate
What is the amino acid which matches aspartate
a. glutamate
b. oxaloacetate
c. alanine
d. pyruvate
b. oxaloacetate
What is the amino acid which matches pyruvate
a. glutamate
b. oxaloacetate
c. alanine
d. arginine
c. alanine
Which of these is an essential amino acid? A) Threonine B) Glycine C) Tyrosine D) Alanine
A) Threonine
Which of these is a non-essential amino acid? A) Lysine B) Methionine C) Valine D) Serine
D) Serine
What is the nitrogen intake value for adults? A) ~120 mg N/kg/day B) ~115 mg N/kg/day C) ~50 mg N/kg/day D) ~95 mg N/kg/day
D) ~95 mg N/kg/day
Which of the following are not ketogenic?
a. leucine
b. lysine
c. tryptophan
d. succinate
d. succinate
Which one isn’t both ketogenic and glycogenic?
a. isoleucine
b. leucine
c. lysine
d. phenylalanine
c. lysine
What is isoleucine oxidised into?
succinyl coA and acetyl coA
What is leucine oxidised into?
acetoacetate and acetyl coA
What is valine oxidised into?
succinyl coA
