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66 Cards in this Set
- Front
- Back
Name and describe 6 dietary components
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1.Carbohydrates - NOT required in diet, liver can synthesize from other sources
2.Fats - 2 essential fatty acids are required in the diet - LINOLEIC and LINOLENIC acids 3.Protein- required to sustain life, there are 10 essential amino acids in children (9 in adults) 4.Vitamins - cofactor for enzymatic reaction,some act as hormones (A, D) 5.Minerals- maintain electrolyte balance (Na and K), provide structure (Ca and P) 6.Water- universal solvent |
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Whats the name of the process that generates energy
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Oxidative
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Whats the name of the process that uses energy for biosynthetic reactions
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Reductive
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Glycogen is the storage form of what?
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Carbohydrates, glycogen and starch are very similar in structure, glycogen is stored in animals, starch in plants
-consists of monomeric units of glucose in chains |
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Where is glycogen stored?
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LIVER and MUSCLE
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Triacylglycerol is a storage form of what?
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Fat
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Where is triacylglycerol stored?
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In healthy individual stored in adipose tissue
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Protein is a storage of what?
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Amino acids, consists of amino acids linked together by PEPTIDE bond - very strong bond
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How many essential amino acids? Name them
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10 (9 in adults)
PVT TIM HALL - Phenylalanine Valine Threonine Tryptophan Isoleucine Methionine Histidine Arginine Lysine Leucine |
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Amount of energy produced by oxidizing carbohydrates
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4 kcal/g
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Amount of energy produced by oxidizing proteins
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4 kcal/g
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Amount of energy produced by fats
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9 kcal/g
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Amount of energy produced by alcohol
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7 kcal/g
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Describe general structure of amino acid
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-Contain a CARBOXYL group, AMINO group and SIDE CHAIN, all attached to alpha carbon
-xcept GLYCINE (no side chain) and PROLINE (N part of the ring) |
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What is the usual configuration of amino acids (L or D)
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L (except GLYCINE which is neither L nor D, because its not optically active and does not rotate polarized light)
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What is the ionization of carboxyl and amino group of amino acids
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At physiologic pH, amino acids carry a positive charge on their amino groups and a negative charge on carboxyl groups
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Name 20 amino acids and their abbreviations
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Alanine (Ala)
Arginine (Arg) Asparagine (Asn) Aspartate (Asp) Cysteine (Cys) Glutamate (GLu) Glutamine (Gln) Glycine (GLy) Histidine (His) Isoleucine (Ile) Leucine(LEu) Lysine(Lys) Methionine(Met) Phenylalanine (Phe) Proline (Pro) Serine (Ser) Threonine(Thr) Tryptophan(Trp) Tyrosine (Tyr) Valine (Val) |
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Name non polar aliphatic amino acids
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1. GLYCINE - simplest amino acid, doesnt have an R group, only H
2.ALANINE 3.LEUCINE 4.ISOLEUCINE 5.VALINE 6.PROLINE-N is part of the ring Isoleucine, leucine, valine and alanine all have non polar bulky hydrophobic side chains. Electrons are shared equally between C and H, so there is no H bonding with water. |
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Name aromatic amino acids
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Aromatic amino acids have 6 membered rings and 3 double bonds
PHENYLALANINE TRYPTOPHAN TYROSINE Phenylalanine has no substituents on the ring so its hydrophobic (nonpolar) Tryptophan has N as a substituent on the ring so it can H bond with water and therefore is polar hydrophilic Tyrosine has OH group on the ring and is also polar hydrophilic |
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Name aliphatic, polar, uncharged amino acids
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Those are amino acids whose side chain is an amide - ADPARAGINE and GLUTAMINE or hydroxyl group - SERINE and THREONINE
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Name sulfur containing amino acids
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CYSTEINE
METHIONINE -Cysteine has SH as a substituent and can react with another cysteine and form CYSTINE through disulfide bonds Methionine has only S as a substituent and cant form disulfide bonds |
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Which amino acids are acidic
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Negatively charged amino acids - ASPARTATE and GLUTAMATE
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Which amino acids are basic
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Positively charged amino acids - ARGININE, LYSINE, HISTIDINE
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What is the main function of an amino acid in the protein
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it forms PEPTIDE BOND, covalent bond between alpha carboxyl group of one amino acid and alpha amino group of next one
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What does linear sequence determine in protein
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LINEAR SEQUENCE determines 3D structure of the protein and its biological properties
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What determines function of the protein
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3D structure
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Whats a primary structure of the protein
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Sequence of amino acids along polypeptide chains
-Ser-Ala-Glu-Val- |
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Whats a secondary structure of a protein
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various types of local conformations in which atoms of side chains are not involved
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Define tertiary structure of protein
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Overall 3D conformation
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Quaternary structure of a protein
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Spatial arrangement of subunits in a protein that consists of more then one polypeptide chains, subunits are joined together by NONCOVALENT INTERACTIONS (same as 3D)
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Name 3 types of proteis
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FIBROUS
GLOBULAR MEMBRANE SPANNING |
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Describe fibrous proteins
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-structural or mechanical roles
-polypeptide chains interwined to form fibers -example - hair, fur, skin |
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Describe globular proteins
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-functional, non-structural
-chains folded on itself to give compact, rounded structure -most are water soluble -example - enzymes, antibodies, transport proteins |
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Name two types of H bonding in secondary structure of protein
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Intramolecular - between different parts of same chain - ALPHA HELIX
Intermolecular - between different chains- BETA PLEATED SHEET |
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What stabilizes secondary structure of protein
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H bonding between carbonyl oxygen of one peptide bond and amino hydrogen of another
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Alpha helix
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common in globular proteins, membrane spanning proteins and DNA binding proteins
-has stable rigid conformation -carbonyl of peptide bond interacts with NH of peptide bond four amino acid residues along the chain |
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Beta Sheet
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-H bonding occurs between neighboring strands running parallel to each other
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Describe structure of keratin
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-strong rope like structure of interwined ALPHA HELIXES
-major component of external protective layer -skin, hair, nails |
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What is the difference between hard and soft keratins
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-HARD KERATINS have high sulfur content and form many S-S bonds between chains
-SOFT KERATINS have low sulfur content and very few S-S bonds between chains |
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Describe structure of collagen
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-consists of THREE CHAINS that wind around each other to form a TRIPLE HELIX
-Collagen contains about 1000 amino acids, 1/3 of them is GLYCINE, others are PROLINE, HYDROXYPROLINE, or HYDROXYLYSINE |
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What offers rigidity to collagen
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PROLINE
HYDROXYPROLINE |
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What is a fundamental unit of collagen
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TROPOCOLLAGEN - triple hellical rod, rigid (not elastic like alpha helix), wider then alpha helix to accomodate bulky residues of PROLINE and HYDROXYPROLINE
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Describe post translational modification of collagen
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-PROLINE and LYSINE are HYDROXYLATED by reaction that requires vitamin C and O2
HYDROXYPROLINE forms H bonds between chains HYDROXYLYSINE forms covalent bonds between chains CROSS LINKS are produced and stabilize structure |
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Name collagen disorders
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-SCURVY - defficient collagen
-Osteogenesis imperfecta (brittle bone disease) -Alports syndrome -Ehlers-Damons syndrome -Epidermolysis Bullosa Dystrophica |
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Describe protein folding
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Proteins fold during and following synthesis along same principles as micelle formation - POLAR amino acids on surface, NON POLAR inside
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What assists in vivo proten folding
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Molecular chaperones (heat-shock proteins) - use ATP energy to change conformation of a protein
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Describe domains in proteins
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Domains are physically independent regions within overall tertiary structure of large, complex protein.Usually visually obvious, like different regions within molecule
Example - extracellular domain, catalytic doman, transmembrane domain |
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Describe solubility of globular proteins
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Soluble in water, core of globular protein has high content of non polar amino acids, its not in contact with water and its densely packed to maximize van der waals forces.
On the surface of the protein are polar amino acids which are charged which are in contact with water |
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Describe prion diseases
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-Protein conformational disease caused by misfolded proteins
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Name forms of prion disease
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-genetic (point mutation)
-Creutzfeld-Jacobs -Bovine spongiform encephalopathy -Scrapie (sheep) |
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How are prion diseases acquired
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-spontaneous mutation in gene encoding PrPc
-ingesting nervous tissue of infected animals -injection of human growth hormone -cannibalism |
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Describe normal and misfolded proteins in prion disease
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PrPc is a normal protein foind on surface of neurons
PrPsc is disease form of protein that has same sequence of amino acids but different tertiary structure (3D), it aggregates and is abnormally resistant to breakdown INTRODUCTION OF ABNORMAL PROTEIN CAUSES CONVERSION OF NORMAL TO ABNORMAL PROTEINS |
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Describe polymorphism
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Variation of primary structure of protein, generally arise from mutations in DNA
Can be without or with consequences (sickle cell disease -called polymorphism only when there is a significant frequency of population (20-30%) |
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Describe sickle cell polymorphism
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-Different structure of sickle cell Hb tends to polymerize in deoxy form
-Distorts RBC into rigid sickle shape -Sickle cells are more easily degraded which results in anemia -Sickle cells tend to block peripheral blood vessels causing ischemia and pain |
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Define homolog proteins
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-Proteins with highly similar sequence
-evolved from same ancestor |
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Define Orthologs
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-From DIFFERENT species
-originated from same gene in ancestor -normally retain function- insulin is same in humans and pork |
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Define Paralogs
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-from SAME species
-originate from common ancestral gene -may have differnet functions - myoglobin, different hemoglobin chains |
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Protein isoforms
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-Perform essentially same function
-are highly homologous -evolved from same ancestral gene -possess DIFFERENT amino acid sequences and chemical and physical properties |
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Define isozyme
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Proteins isoforms which are enzymes
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Structure of hemoglobin
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HbA (adult) consists of FOUR POLYPEPTIDE CHAINS each containing molecule of HEME
Chains are SIMILAR in 3D configuration and to single chain of myoglobin, but have DIFFERENT sequences. |
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Describe function of hemoglobin
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OXYGEN SATURATION curve for Hba is SIGMOIDAL. Each HEME binds ONE O2. When O2 binds, HbA changes from T form (taut) to R (relaxed). Binding to one heme increases affinity for others.
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What effect does binding of 2,3-BPG have on affinity
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DECREASES affinity og HbA for O2, so its more readily released in tissues when its bound
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Fetal Hb
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-Has LOWER affinity for BPG then HbA, so HIGHER affinity for O2
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Define denaturation of proteins
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3D structure and biological activity of protiens is lost without breaking peptide bonds
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Conditions that can denature proteins
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-Extremes of pH
-High temperature -Organic sollvents (alcohol) -Salts of heavy metals (mercury) -Radiation |
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Describe cystinuria
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Normally amino acids are filtered by glomerular capillaries. Cystinuria is a genetic disease where protein is missing that normally responsible for rabsorption of cystine, arginine and lysine from kisneys. So, urine has elevates cystine, which precipitates and forms renal stones
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