Human Biochemistry B.5-9

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Human Biochemistry B.5-9
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nutrients

• Food required in the diet
• Recommended daily intake
• Micro less than 0.005 of body mass mg or µg per
  day
• Vitamins and minerals
• Needed to produce enzymes or other substances
  needed for health

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Macronutrients

• For energy and structure
• Proteins, carbohydrates, lipids
• Na,Mg,K,Ca,P,S and Cl

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• Dietary minerals
• Major mineralsin bone Calcium, phosphate,
  magnesium
• Major mineralsin electrolytes Sodium, potassium,
  chloride
• Minor mineralsin metalloproteins Iron, copper,
  manganese, iodine, cobalt, molybdenum, selenium,
  chromium, fluoride, zinc
• Trace minerals Nickel, silicon, vanadium, tin

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• Electrolyte results
• Test Patient's Results Ref. RangeUnits
• BMP
• Na L124 136-145mEq/L
• K H5.8 3.5-5.1mEq/L
• CO2 25 23-29mEq/L
• Cl 101 98-107mEq/L
• Glucose H107 74-100mg/dL
• Ca 10.1 8.6-10.2mg/dL
• BUN 17 8-23mg/dL
• Creatinine0.9 0.8-1.3mg/dL
• Key LAbnormal Low, HAbnormal High, WNLWithin
  Normal Limits, critical value

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Vitamins

• Needed but not synthesized in the body
• Water or fat soluble
• Water -filtered out by kidneys and excreted
• Fat -absorbed and stored in fat tissues
• Look at table 21 of the IB data booklet

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• ADEK fat
• all others water

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• Look at data booklet
• Vitamin A (retinol)structure
• Fat
• Important for vision at low light intensity

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• Look at vitamin C (ascorbic acid)
• Water
• Cofactor in enzyme reactions
• Tissue regeneration after injury

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• D (calciferol)
• Fat
• Similar in structure to cholesterol
• Uptake of Ca2 by cells
• Healthy bones and teeth
• Get by sunlight or put in milk

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Deficiency diseases

• Pick one for a report (in pairs)
• Vitamin A, Iodine, iron, niacin, thiamin, vit. C,
  D, selenium, protein
• Describe disease, pictures?, reasons, solutions

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General summary of nutrient problems

• What is the problem in the USA?
• Worldwide causes and solutions
• do questions 9 and 10

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B.6 Hormones

• Communication systems
• Nervous electrochemical quick
• Endocrine chemical messengers slower
• Different types of molecules
• Produced in glands (no ducts)
• Receptors are target cells

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Hormones
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• Another report
• ADH, thyroxine, aldosterone, adrenaline, insulin,
  estrogen, progesterone, testosterone
• Gland, type of molecule, target cells, functions

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• Look at your data booklet on hormones
• Compare cholesterol, estradiol(estrogen),
  progesterone, testosterone
• Alike and differences

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Oral contraceptives

• Prevents ovulation
• Mixture of progesterone and estrogen
• Prevent release of follicle stimulating and
  luteinizing hormones
• No ovulation, simulates pregnancy

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Use and abuse of steroids

• Hormone replacement therapy at menopause
• Male steroids (anabolic) androgens like
  testosterone
• Enhance male characteristics
• Overuse aggressive, liver cancer

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• Do questions 11 and 12

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B.7 Enzymes

• Control system of the body
• Biological catalysts

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structure

• Globular proteins-several hundred amino acids
• Tertiary and quaternary structures important
• Co-factors binding non-protein molecules
• Organic called coenzymes inorganic metal ions
• Examples vitamins

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Catalytic action

• Define enzyme
• Reactant is a substrate
• Enzyme substrate complex
• Active site on the enzyme is a pocket or groove
  on the surface
• Enzyme is larger than substrate

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• Animation
• Another animation

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saturation

• 
  
• 3 things this tells us

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• Low conc. Rate relates to substate
• As conc. Increases enzyme gets tied up
• High conc. Rate constant

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Michaelis-Menten Equation

• Vmax turnover number
• molecules/second

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Michaelis constant Km

• ½ Vmax
• Specific pH and temp.
• Units of concentration
• Low Km quick reaction constant rate

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Enzyme activity

• Temperature
• Increase rate as temp goes up
• At a point the protein denatures

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• Human optimum tends to be 37 oC
• Denaturation usually is irreversible
• Lowering temperature only causes deactivation
• High fevers can be fatal

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pH

• Changes affect the equilibrium positions
• If it affects the R groups in amino acids it will
  alter the attractive ability thus influences the
  shape
• Each enzyme has an optimal pH
• Extremes cause denaturation

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For humans 7.4
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Heavy metal ions

• Lead, copper, mercury and silver
• Poisonous
• React with SH groups on cysteine to make S-metal
• Changes shape

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Chemical inhibitors

• Competitively at the active site
• Non-competitively at another area

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Competitive inhibitors
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• Takes a higher substrate concentration to reach
  Vmax

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• Chymotrpsin is an enzyme which hydrolyzes
  peptides at the carbonyl side of tyr or phe or
  trp (i.e. those that have an aromatic side chain.
  In the graphic on the left, the substrate and the
  irreversible inhibitor are shown in the active
  site pocket. In the case of the inhibitor the
  reaction starts in the same way as with the
  substrate, but the end result is that the
  inhibitor is covalently bonded to the
  histidine-57 in the active site and is not
  reversible

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• Changes shape of enzyme
• Increasing concentration doesnt help
• Poisons DDT, cyanide and antibiotics
• Means of controlling metabolic activity in
  healthy cells
• Thermostat and heater

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Enzymes vs. catalysts

• Enzymes are
• Specific
• Reaction saturation
• Speed up 1000 to 1000000 times
• Can be inhibited
• Very sensitive to environmental changes

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• Do questions 13 and 14

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B.8 Nucleic acids

• DNA and RNA
• Information storage of genetics in the nucleus
• How did it begin?

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• DNA must be stable
• Contain a code
• Be able to replicate

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Nucleic acid structure

• Polymers of nucleotides
• Three components
• 1. pentose sugar
• ribose

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• Deoxyribose C2 lacks an OH

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2. Phosphate group

• PO43

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3. Nitrogenous base

• Purine adenine (A) quanine (G)
• Larger 2 fused rings
• Or pyrimidines smaller one ring

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DNA bases
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RNA

• Uracil replaces thymine one less CH3

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PO4 connects to the 5 carbon on the sugar, sugar
connects from the 1 carbon
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simplified
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• Joined together by condensation reactions
• Phosphate on the 3 carbon of the adjoining sugar
• Called phosphodiester links

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polynucleotides
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simplified
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• Putting it together

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• Adenine pairs up with thymine (uracil in RNA)
• Cytosine and guinine pair up
• Held together by hydrogen bonds

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Double helix
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• 1 turn for each 10 nucleotides
• Each side is upside down to each other
• Animation
• The dna game

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RNA

• Single strand
• Ribose instead of d-ribose
• Uracil instead of thymine
• 3 types messenger (mRNA), transfer (tRNA),
  ribosomal (rRNA)

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transcription

• In the nucleus, Strands of DNA separate (unzip)
• mRNA copies the code by lining up bases
• mRNA leaves nucleus
• DNA zips up

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translation

• Happens in the ribosome
• tRNA pulls in amino acids from the cytoplasm to
  make proteins
• Codons every 3 nucleotide is the code for 1 amino
  acid
• Activity for building a protein

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• Animation
• One more

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DNA profiling

• Only 0.1 of DNA is different in humans
• 3 billion base pairs unique

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steps

• Obtain DNA from blood, saliva etc.
• Cut into restriction enzymes
• Make multiple copies
• Use gel electrophoresis
• Irradiated for a autoradiogram
• For identity of victims, suspects, paternity,
  relationships

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• Question 15

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B.9 Respiration

• Release of energy
• Glucose breakdown

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aerobic

• Oxygen present
• Pyruvate oxidized to CO2 and H2O
• Electron transport carriers-cytochromes
• animation

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Anaerobic

• Without oxygen
• Glycolysis
• Glucose into pyruvate
• Coenzyme NAD
• Forms lactic acid
• Only 2 of energy released
• animation

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• Electron transport system involves Fe2 to Fe3
• CU1 to Cu2
• Cytochrome
• Cytochrome oxidase passes e- to O2 to make H2O

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Hemoglobbin

• O2 bound to it
• Fe2 stays in this state
• Reversible oxy hemoglobbin

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• Question 16
• Do the questions on page 541-545 in your textbook
  and 104 in your study booklet