proteins – Chemistry Test Answers

Flashcard maker : Bettina Hugo
Nucleoside
purine or pyrimidine covalently bonded to a sugar
Nucleotide
nucleoside to which 1-3 phosphate groups are covalently bonded
Nucleic Acids
Polymer of nucleotides covalently liked by phosphodiester bonds
Deoxyribonucleic Acid
(DNA) double stranded nucleic acid composed of repeating nucleotides
Ribonucleic Acid
(RNA) Single stranded nuclein acid found in every living cell.
Gene
single stranded section of DNA that codes for proteins
Chromosome
liner, double stranded, carry all of an organisms genetic information.
Metabolism
the sum of all biochemical reactions that occur within a cell.
Chemical Components of Nucleotides
* Pentose Sugar
* 1-3 Phosphate Groups
* Nitrogenoous base
Components of DNA
Nitrogenous Bases: Adenine, Guanine Thymine & Cytosine
Pentose Sugar – Deoxyribose
Phosphate Groups
Mutation
a change in the DNA base sequence in a gene. can result from substitutions, insertions or deletions.
How can mutations affect a protein?
1) No effect
2) Diminished or complete loss of protein function.
3) Creation of a new function
Components of RNA
Nitrogenous bases: Adenine, Guanine, Uracil, Cytosine
Pentose sugar – Ribose
Phosphate Groups
Structure of RNA
single stranded
complementary paired bases:
Adenine – Uracil
Guanine – Cytosine
Messenger RNA (mRNA)
carries genetic information for a protein from DNA to the ribosomes
Ribsomal RNA (rRNA)
the “platforms” where protein synthesis occurs.
Transfer RNA (tRNA)
delivers the correct amino acid to the ribosome to be incorporated into a new protein
Transcription
DNA->RNA The process in which a gene is a template for the creating of RNA.
Occurs in the cell nucleus
Translation
mRNA->Protein
the process where mRNA is used to create a protein.
Occurs in cytolplasm on ribosomes.
Codon
The three base sequences that encode a single amino acid
Replication
process by which DNA is copied, basis for biological inheritance.
Occurs in the nucleus.
Protein
polymer of amino acids covalently joined by peptide bonds.
Peptide Bond
Covalent bond between the carboxyl group of one amino acid and the amino group on another.
Zwitterion
ion that has both a positive and a negative charge. formed as the amino group is protonated and the carboxyl group is dissociated.
Denaturation
the organized structure of a protein is disrupted. Results in loss of function.
Acute Phase Reactants (APR)
proteins whose concentrations change after trauma, burns, etc.
Cryoglobulin
precipitate or gel whens erum is cooled, but re dissove when it is warmed.
Immunoglobulins
antibodies
Elements contained in all proteins
Carbon, Hydrogen, Oxygen, Nitrogen
R-Group
hydrophobic or hydrophillic, a variable group of atoms attatched to every amino acid.
Primary Structure of Proteins
linear sequence of amino acids, held together by polypeptide bonds.
Secondary Structure
folding of the primary structure. cause principally by hydrogen bonds.
Tertiary Structure
additonal folding of the secondary structure, places hydrophobic AA on the inside and hydrophillic on the outside.
Quaternary Structure
overall 3-D folding of 2 or more polypeptides.
Globular Protein
compact, spherical structures, generably soluble in salt, most proteins in body.
I.E. albumin, antibodies, enzymes, hormones, and hemoglobin.
Fibrous Proteins
relatively long, generably insoluable in salt, represent structural protiens, I.E. Collagen, Elastin, Keratin, Actin, Myosin
Functions of Proteins
1) Antibodies
2) Catalyze biochemical reactions
3) Transport molecules
4) regulatory roles
5) structure
6) movement
7) nutrients
Hemoglobin
oxygen carrying protein found in RBCs, contains 4 heme groups and 4 polypeptides.
Functions of Hb
Gas Transport
Acid Base Balance
Components of Hb
Heme
Globin
Heme
Protoporphyrin IX ring, and Ferrous Ion
Site of Heme Synthesis
Bone Marrow.
Aminoeleluniv acid (ALA) Synthase
catalyzes the initial step, heme inhibits this enzyme.
Lead Inhibition
inhibits all steps in porphyrin synthesis by denaturation
Myoglobin
found in muscle tissue, reserve supply of O2. contains one polypeptide and one protoporphyrin ring.
What are the factors affecting Oxygen Transport?
Partial PRessure of Oxygen, PH, Temperature, 2,3-DPG
How does decreased P50 affect O transport?
shift to the left, and an impaired oxygen release to tissues
How does an increased P50 affect O transport?
shift to the right, eases the delivery of oxygen to tissues.
How does Increasded blood acidity affect O transport?
decrease PH, shift to the right, lowering of affinity for O2
How does decreased blood acidity afftect O transport?
increased PH, shift to the left, increase affinity for O2
How does temp increase affect O transport?
hemoglobin more readily releases O2, shift to the right.
How does temp decrease affect O transport?
hemoglobin less readily releases O2, shift to the left.
2,3-DPG is significant because?
essential in enabling the unload of O2 and it is the most important factor that affects O2 transport.
What are the 4 forms of normal Hemoglobin?

1) Normal Hb A

2) Normal Variant Hb A2

3) Normal Variant Hb A1c

4) Fetal Hb F

Why is Hb A1c Significant?
the concentrations serve as an indicator for prolonged high glucose concentrations, used to monitor diabetics
Bilirubin
the breakdown product of the normal heme catabolism.
What happens to Iron during heme catabolism?
iron is recycled, by being released from the heme and then returned to the plasma, then it is carried to the bone marrow.
What are the factors that denature proteins?
Heat, organic solvents (Alcohol), Detergents, salting out, pH changes, HEavy metals, mechanical stress
How does heat denature proteins?
as temp increases, molecular motion inceases, bonds are disrupted.
Simple Proteins
yield only amino acids when hydrolyzed. I.E. albumin, insulin, fibrinogen.
Conjugated Proteins
yield amino acids, and a non protein substance upon hydrolysis
Glycoproteins
covalently linked carbohydrate
Phosphoproteins
covalently linked phosphate groups
Lipoproteins
covalently linked lipids, like cholesterol, triglyceride, and phospholipids.
Metalloproteins
contain ions and are often colored. I.E. chlorophyll and hemoglobin
Essential Amino Acids
isoleucin, leucin, lysine, methionine, phenylalanine, threonine, tryptophan, and valine
Liver uses amino acids, for:
Growth, maitenence, repair, enzyme production, albumin, lipoproteins.
Where are immunoglobulins produced?
B lymphocytes that originate in bone marrow
Where are plasma proteins synthesized?
in the liver, circulate the blood stream.
Prealbumin
Tryptophan rich tetrameric glycoprotein, mainly synthesized in the liver.
Prealbumin Function
Carrier for thyroid hormones, and Vitamin A.  Used to assess the patients nutritional state.
Clinical Significance of Prealbumin
decreases in liver disease, increases with steroid use, pregnancy and chronic renal disease.
Antibody
immunoglobulins. produced in response to an antigen.
Antigen
substance that stimulates antibody formation
Phenylketonuria (PKU)
genetic deficiency of the enzyme phenylalanine hydroxylase
Maple Syrup Urine Disease (MSUD)
genetic deficiency in the enzyme that degrades the branched chain amino acids; branched chain alpha ketoacid dehydrogenase
Causes of Hypoproteinemia

  • starvation
  • excess loss in urine
  • chronic liver disease
  • inflammatory conditions

Causes of Hyperproteinemia

  • dehydration
  • increased synthesis of gamma globulins
  • measurement of unexpected protein (caused primarily by lab error)

Porphyrin Conditions

Porphyrinuria – excessive excretion in urine

Porphyrinemia – presence of porphyrin in the plasma or serum

Porphyrin Disorders

Hereditary – genetic disorders from impaired activeity of enzymes

Acquired – more common; lead poisoning, renal failure, iron deficiency, liver disease

Photoporphyrias
cutaneous porphyria that presents itself with exposure to light.
Thalassemias
disease state from globin genetic mutations that result in little globin protein being produced.  It affects Hbs O transport.
Sickle Cell Anemia

Hb S sickled RBC, most common type of abnormal Hemoglobin, results from single mutation of the B globin.

can be life threatening.

Carbaminohemoglobin (CO2Hb)
compound of CO2 and Hb.
about 10-20% of co2 binds to globin, forming this.
Methemoglobin (M-Hb)
hemoglobin where the iron molecule is oxidized to Fe+3 which cannot bind oxygen. 

Sulfhemoglobin (S-Hb)

 

green pigmented compund of hydrogen sulfide and Hb.

irreversible oxidation, sometimes after exposer to TNT, or sulfur.

Carboxyhemoglobin (COHb)

formed by the binding of CO to heme.

normally .2-.8% smokers up to 10%. Co poisoning exhibits cherry red color.

Cryoglobulin Clinical Significance
seem in myeloma, macroglobulinemia, autoimmune diseases like, rheumatoid arthritis, & SLE
Functions of Immunoglobulins

  • neutralize toxic substances
  • aid phagocytosis
  • kill pathogens
  • combine with antigens and destroy cells

5 classes of Immunoglobulins
IgG, IgM, IgA, IgD, IgE
Multiple Myeloma
malignant diseases caused by the presence of neoplastic plasma in bone and bone marrow
How are Bence-Jones Proteins analyzed?

Heating urine to 40-60C, they will precipitate while others remain in solution. at 100C proteins will redissolve.

Cooling reverses this.

C-reactive Protein (CRP)
APR, most sensitve indicator of inflammation, rises about 8 hours after onset, increases in all bacterial infections, rarely with viral 
Haptoglobin
APR concentrations increase in hypoalbuminemia states like nephrotic syndrome.
Ceruloplasmin
APR carries 90% of the copper in plasma
Alpha1-antitrypsin
may protect the body from proteolysis by proteases released from leukocytes and macrophages.
Alpha2-macroglobulin
Protease inhibitor
Fribinogen
Essential blood clotting protein
C3/C4
Early components of the complement system
Transferrin
transport protein for iron. decrease seen in inflammatory response
Albumin
Levels may decrease to divert protein production away from the liver and towards the components increasing for inflammatory response
Prealbumin
Decrease related to protein malnutrition

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