Proteins Flashcards
What are the recommendations for protein?
increase variety, lower fat animal sources, legumes(dried beans,lentils,peas)
Name the 3 functions of proteins
- Maintenance and regulation of body functions(enzymes,hormones,accumulation of lean tissue,immune system)
- Growth
- Energy
How can protein be used as energy?
- Converted to glucose, and other amino acids
- Converted to fat and stored (as fat from glucose)
- Burned as fuel(carbon skeleton in TCA cycle)
Can protein be fattening?
Yes
How do we store macromolecules?
We store carbohydrates as glucose in glycogen, fatty acids as fat in adipose cells, we do not store protein
What are the functions of amino acids?
- Precursors of neurotransmitters (dopamine,serotonin), nucleotides, melanin, thyroid hormone, histamine (from histidine, when we have an allergy or a very bad cold)
- Peptides
- Proteins
How much protein do we make in a day?
300 g of protein/day
What % of proteins circulate in blood?
25%
Name the 3 types of proteins in blood.
- Plasma proteins(albumin,pH buffering, fibronogen)
- Red blood cells (hemoglobin)
- White blood cells
Name the 4 roles of plasma proteins.
- Nutrient transport(albumin,transferrin)
- Acute phase proteins (protection, blood clotting)
- pH buffering ( fibronogen)
- Regulation of fluid balance
What do red blood cells do?
Transport oxygen, packed with hemoglobin
What do white blood cells do?
Antibodies and immune effectors
How much does the production of immune system increase to an inflammation?
By 30 %
What is the lifespan of hemoglobin?
120 days
Which cells in blood have DNA?
White blood cells
Name the 2 types of proteins.
Tissue Proteins
Secretory Proteins
Give examples of tissue proteins.
enzymes, structural proteins, membrane receptors, carriers
Give examples of secretory proteins.
digestive enzymes, human milk proteins, hormones and grow factors
How many amino acids have a tRNA?
20
How many amino acids are essential?
9
Name the essential amino acids.
Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine
Which amino acids are conditionally indispensable?
Arginine, cysteine, glycine, glutamine, proline, and tyrosine.
What does the concept conditionally indispensable mean?
Needed in the diet under certain conditions. (premature babies, liver disease)
What aa is needed with rapid growth?
Arginine
Which protein has disulfide bonds?
Insulin
Describe the formation of insulin molecule
Posttranslational modification, in which disulfide bonds are made and the c part is chopped. Looks like there are two peptides, indeed it is one.
How can we assess the work of pancreas?
By measuring C chains from insulin in the urea
What are the methods to denature proteins?
Heating, pH, organic solvents, detergents
Which enzyme cleaves proteins in the stomach?
Pepsin (pepsinogen-precursor)
Is heme an amino acid?
No, it is a special product from amino acids, but the amino acid
Which enzyme cleaves proteins in the small intestine?
Trypsin and many more
Where are the enzymes from the small intestine from?
Pancreas
What macromolecules start to be digested in the mouth?
Starch and Fat, but not the protein
What happens to the proteins in the stomach?
With the HCl the protein is danatured, making its more available for pepsin. It cleaves strands int polypeptides, tripeptides, dipeptides and a few amino acids
What happens to the proteins in the small intestine?
Pancreotic proteases split the peptide chains into tripeptides,dipeptides and amino acids
Where are amino acids absorbed?
Intestinal cells absorb(AAs transporters) and transfer amino acids to the bloodstream
Where is the last stage of protein digestion?
The brush border(dipeptidases)
How do amino acids get to the bloodstream?
AA go to portal vein, then bloodstream transports AA to the body
Differentiate allergies and intolerances.
Allergies: immune response to a specific protein Intolerances: not immune, could be a digestion problem for example
Define transcription.
1st step: segment of DNA copied into RNA (mRNA) by the enzyme RNA polymerase