Biochemistry Review

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Biochemistry Review

• Melissa Allen, Hilary Alterman, Jaimie Bandur,
  Tim Bender

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• 3.1.4 Draw and label a diagram showing the
  structure of water molecules to show their
  polarity and hydrogen bond formation.
• 3.1.5 Outline the thermal, cohesive, and solvent
  properties of water

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Diagram of Water Molecules
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Properties of Water

• Cohesive properties
• Water molecules stick together
• Affects different living systems
• Allows insects to walk on water
• Allows for water transport in plants

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Properties of Water

• Solvent properties
• Water molecules are polar. They are attracted to
  the strong ionic charges of the ions in the
  solution.
• For example, Na ions exert a strong attraction
  on water molecules, forming shells around the
  ion.
• This causes ions to isolate from one another.
  Process is called solubility

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Properties of Water

• Thermal properties
• The hydrogen bonds allows storage of kinetic and
  potential energy
• Water absorbs a lot of heat before there is a
  change in temperature, therefore making water a
  useful substance for living organisms to utilize

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• 3.1.6 Explain the relationship between the
  properties of water and its uses in living
  organisms as a coolant, medium for metabolic
  reactions and transport medium.

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Relationships

• Cooling effects
• The heat generated by the body needs to be
  removed to prevent denaturation in enzyme systems
• Water absorbs a great deal of energy before
  becoming vapor
• Effective agent for heat removal maintaining
  body temperature
• Blood (composed of water) can absorb and carry
  heat away from hot parts of the body to cooler
  parts.

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Relationships

• Medium for metabolic reactions
• Water is a universal solvent
• Substances are easily broken down
• Example water helps break down NaCl by forming a
  barrier around the Na Cl by separating the two

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Relationships

• Transport medium
• Water is a solvent in blood, tissue fluid, and
  cytoplasm
• Water allows soluble minerals, carbohydrates, and
  amino acids to be transported

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• Identify amino acids, glucose, ribose, and fatty
  acids from diagrams showing their structure. Be
  able to sketch each one.

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Amino Acids
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Glucose
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Ribose
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Fatty Acids
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• 3.2.3 List three examples each of
  monosaccharides, disaccharides and
  polysaccharides.

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Subcategory Example molecules
Monosaccharides Glucose, galactose, fructose
Disaccharides Maltose, lactose, sucrose
Polysaccharides Starch, glycogen, cellulose
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3.2.4 List one function of glucose, lactose and
glycogen in animals of fructose, sucrose and
cellulose in plant.

• Animals
• Glucose - blood sugar
• Lactose - milk sugar
• Glycogen - energy storage
• Plants
• Fructose - honey, fruit sugar
• Sucrose - plant sap
• Cellulose - cell wall structure

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3.2.5 Outline the role of condensation
hydrolysis in relationships between mono-, di-,
and polysaccharides

• Monsaccharides form glycosidic bond to form a
  disaccharide, more bonds to form a polysaccharide
• Fatty Acids 3 fatty acids 1 glycerol. 3 ester
  bonds 1 triglyceride
• Amino acids- peptide bonds, dipeptides or
  poypeptides

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Condensation reaction of amino acids to form a
dipeptide
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3.2.6 State 3 functions of lipids

• Concentrated sources of energy
• Waterproofing
• Waxy cuticle in plants, feathers of ducks
• Cushions and absorbs shock to protect organs

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3.2.7 Compare the use of carbohydrates and lipids
in energy storage
Carbohydrates Lipids
-Stored as glycogen -Stored as fat
-Short term energy storage -Long term energy storage
-Released more quickly-easily digested -More energy per gram
-Easier transport - more water soluble - Insoluble in water- less osmotic effect
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7.5.1 Explain the 4 levels of protein structure
and indicate the significance of each

• Primary- Sequence of amino acids with peptide
  bonds. Redefines final shape based on chemical
  interactions
• Secondary- Shape of polypeptide alpha helix coil
  or beta pleated sheet. Uses hydrogen bonds
• Tertiary- Fold of proteins due to reactions
  between R groups disulfide, ionic, hydrogen
  bonds, and hydrophobic interactions
• Quarternary- Polypeptide chains different groups
  have different functions

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7.5.2 Outline differences between fibrous and
globular proteins and give 2 examples of each

• Globular
• Can be single chains
• Easily soluble in water
• Tertiary structure critical
• Round shape
• Can be catalytic, regulatory (hormones),
  transport, protective (antibodies).
• Insulin, hemoglobin

• Fibrous
• Parallel polypeptide chains in long sheets
• Long shapes
• Only in animals
• Water insoluble
• Tough, supple, or stretchy
• Structural or contractile role
• Collagen, actin and myosin

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Explain control of metabolic pathways by
end-product inhibition

• Prevents cell from wasting chemical resources and
  energy
• Assembly line process
• When end product is present and in sufficient
  quantity, the process stops

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• End product binds to allosteric site of the first
  enzyme
• As the existing end product is used up, the first
  enzyme is reactivated

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Inhibition

• Competitive
• Prontosil
• Binds to enzyme for folic acid
• Binds to allosteric site and changes shape of the
  enzyme
• Non-competitive
• Arsenic
• Binds to sulphydral groups of the protein,
  destroying it

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Enzymes lower activation energy

• Enzymes are catalysts --gt speed up reactions
• Influence the stability of bonds
• Provide alternative reaction pathway

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Induced Fit Model

• Enzyme or substrate changes shape in order to fit
• Substrate becomes bound to the enzyme by weak
  chemical bonds
• Shapes return to normal after the reaction

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Metabolic pathways consist of chains and cycles
of enzyme catalyzed reactions
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Use of lactose in production of lactose-free milk

• Lactose is a disaccharide in milk
• Made up of glucose and galactose
• Some people have lactose intolerance
• People who are lactose intolerant cant drink
  milk if its not lactose free
• Lactase --gt enzyme that digests lactose into
  glucose and galactose

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Effects of pH on enzyme activity

• Different enzymes have different pH ranges
• Enzyme activity will increase until optimum pH is
  reached
• Enzyme activity will then decrease because the
  enzyme denatures
• Bell curve

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Effect of Temperature on Enzyme Activity

• No activity at low temperatures
• Enzyme activity increases as temperature
  increases
• Once the optimum temperature is exceeded, the
  rate decreases because the enzyme denatures
• Bell curve

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Effect of Substrate Concentration on Enzyme
Activity

• Enzyme activity increases as substrate
  concentration increases
• Rate plateaus once all of the enzymes are in use

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Functions of Proteins

• Structural
• Collagen
• Regulatory
• Insulin
• Contractile
• Myosin
• Transport
• hemoglobin

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Significance of Polar and Non-polar Amino Acids

• Polar --gt hydrophilic, can contact water
• Non-polar --gt hydrophobic, cant contact water
• Lining of protein channels is polar, so it allows
  for diffusion
• Polar amino acids allow for the positioning of
  proteins on the external and internal surface of
  the membrane