Competency  2  Biochemical  Basis  of  Life  

 Introduc8on  to  Chemistry  

•  Atoms  -­‐  smallest  par8cle  of  an  element  that  has  the  elements  proper8es    

•  protons  (+)  =  Atomic  number    •  neutrons  (no  charge)  •  Protons  and  neutrons  together  make  up  the  nucleus  

•  electrons  (-­‐)  –  used  to  form  bonds  with  other  elements  

Atomic Structure

Electrons  

•   found  in  regions  of  space  called  electron  shells  (energy  shells)  •   each  shell  can  hold  a  limited  number  of  electrons  

•   for  atoms  with  atomic  numbers  of  18  or  less,  the  following  rules  apply:  •     the  first  shell  can  hold  up  to  2  electrons  •     the  second  shell  can  hold  up  to  8  electrons  •     the  third  shell  can  hold  up  to  8  electrons  •     lower  shells  are  filled  first  •     if  the  outermost  shell  is  full,  the  atom  is  stable  

Molecules and Compounds 1.  Molecule: when two or more atoms

combine (usually for nonmetals) Organic compounds all contain CARBON!! 2. Compound: when two or more atoms

of different elements combine –  Two types 1. Covalent 2. Ionic

Covalent  Bond  

Formed  when  atoms  share  electrons.    They  “hold  hands”.      

• Hydrogen  atoms  form  single  bonds  • Oxygen  atoms  form  two  bonds  • Nitrogen  atoms  form  three  bonds  • Carbon  atoms  form  four  bonds  

2-­‐11  

Covalent  Bond  

Ions  

Ion  •   an  atom  that  has  gained  or  lost  an  electron(s)  •   an  electrically  charged  atom  •   atoms  form  ions  to  become  stable    

 •   a  posiMvely  charged  ion  is  formed  when  an  atom  loses  an  electron(s)  

 •   a  negaMvely  charged  ion  is  formed  when  an  atom  gains  an  electron(s)     2-­‐9  

Ionic  Bond  

•   an  aOracMon  between  an  atoms  that  are  negaMvely  and  posiMvely  charged  • “opposites  aOract”  

Ionic  Bond  

•   formed  when  electrons  are  transferred  from  one  atom  to  another  atom  

COVALENT  VS.  IONIC  

Review      

Name  and  describe  the  two  types  of  chemical  bonds.      What  is  an  ion?      How  are  ions  needed  by  living  things?  

   Ions  allow  living  organisms  to  use  elements  to  construct  other  compounds  necessary  for  its  survival.    

– In a polar covalent bond •  Electrons are shared unequally

between atoms, creating a polar molecule

•  Water is a polar molecule! (–)   (–)  

(+)   (+)  

O  

H  H  

1. Water is the solvent of life. Being polar allows water to dissolve ionically bonded compounds easily. When compounds dissolve in water they form a solution.

+  

–  

–  

–  

–  

–  –  

–  

–  

–  –  +  

+  +  

+  +  

Na+  

+  

Na+  

Cl–  

Ion  in  solu8on   Salt  

crystal  

Cl–  

Proper8es  of  Water  

Proper8es  of  Water  2. Hydrogen bonds make water cohesive. The water molecules “stick” to each other, so one H2O molecule holds on to another H2O molecule. This creates surface tension.

 

Proper8es  of  Water  3.  Water is adhesive (holds on to

different/other substances)

ex: molecules can move from a plant’s roots to its leaves

•  Capillary  AcMon  Surface  tension  is  also  responsible  for  another  phenomena  known  as  capillary  ac8on.    Capillary  acMon  occurs  when  water  climbs  upward  through  a  small  space,  defying  gravity  due  to  the  forces  of  adhesion  and  surface  tension.    

Proper8es  of  Water  4.    Expansion  –  water  expands  when  it            freezes,  which  is  opposite  to  most  substances  

–  results  in  ice  having  a  lower  density  than  liquid  water  so  the  ice  floats  

-­‐-­‐  ponds  “freeze  on  top”  so  organisms  are  able  to            live  underneath  the  ice  layer.  -­‐-­‐  problem  for  roads,  water  will  get  in  cracks  of  the          pavement  and  freeze  and  it  will  cause  the  roads          to  crack  and  have  potholes.      

 

Proper8es  of  Water  5. Water has unique thermal properties

a. high specific heat b. high boiling point c. high thermal conductivity d. good evaporative coolant (sweating)

*also called heat of vaporization So,  as  our  sweat  evaporates,  we  begin  to  feel  cooler.      

 

What  is  the  pH  scale?  pH=power  of  hydrogen  

•  Measures  the  concentra8on  of  (hydrogen)  H+  ions  

•  Acids  -­‐    pH  number  below  7  and  a  high  number  of  H+  ions  (low  amount  of  OH-­‐)  

•  Bases  -­‐  pH  number  above  7  and  have  a  high  number  of  OH-­‐    (low  amount  of  H+)  

•  Pure  water  is  neutral  and  has  a  pH  of  7.0        

pH Scale

Acid  rain  -­‐-­‐contains  sulfuric  acid  and  nitric                          acid  

     *  Acid  rain  pH  <  5.6        *  Acid  rain  washes  away  vital    

                           minerals  from  soil,  kills  aqua8c                                organisms  &  strip  nutrients  from            plants  

 

Inorganic Substances-do NOT contain carbon

•  Water –  Most abundant in living things –  Universal Solvent –  Most reactions occur in water –  Transports wastes, nutrients, etc. –  Absorbs heat

•  Oxygen –  Must have in cellular respiration to release energy

•  Carbon Dioxide –  Waste product of cellular respiration

•  Salts –  Major sources on ions used in metabolic processes –  Na, Cl, K, Ca, Mg, P

Organic  substances-­‐all  contain  carbon.  

Name  the  4    major  types  of  organic  macromolecules  are:    1.  Carbohydrates  2.  Lipids  3.  Proteins  4.  Nucleic  acids        

#1- Carbohydrates •  Provides immediate energy for metabolic activites

•  Made of C, H, O

•  Ratio 1:2:1 (C6H12O6)

•  Monosaccharides: simple sugars (glucose) –  These are the building blocks (monomers)

•  Disaccharides: two simple sugars combined together (lactose)

•  Polysaccharides: complex carbohydrates (glycogen, cellulose and starch)

#2- Lipids •  Insoluble in water •  Typically 3 fatty acids and 1 glycerol

(Triglycerides) •  Store energy and have more energy than

carbs •  Made of C, H, O Same elements in carbs,

just don’t have the 1:2:1 ratio. •  Examples-Fats, oils, waxes, steroids,

cholesterol •  Lipids provide insulation, protection,

structure of cell membranes

#3- Proteins •  Provide energy after carbs and lipids

are used up. •  Provide structure, movement of

muscles, transport, regulation, defense for the body

•  Examples-hormones, enzymes, receptors, and antibodies, hair, nails, hooves

•  Building block (monomer) is the amino acid –  20 amino acids of which 12 are

essential •  Made of C, H, O, N •  Held together by hydrogen bonding

(peptide bonds) so heat, pH change, radiation, etc. affect the bonding

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An enzyme is a special kind of protein

1. Most enzymes are proteins that can speed up a chemical reaction and lower the activation energy needed.

2. Enzymes act as catalysts, which make a reaction go faster but without themselves being used up. 3. Usually end in -ase.

1.   Substrate-­‐  substance  being  changed  by  enzyme  

2.    AcMve  site-­‐  region  on  enzyme  where  substrate  aOaches  (this  is  the  enzyme  substrate  complex)  

*Enzymes  work  by  either  breaking  or  forming  compounds.  

*  As  an  enzyme  works,  it  combines  with  it  substrate  and  converts  it  to  products.  

 

 Chemical  ReacMons  and  Enzymes  

36

Factors that can affect Enzyme activity

•  Temperature-­‐low  temps  can  make  enzymes  inacMve,  high  temps  can  denature  the  enzyme  

•  pH  •  ConcentraMons  of  substrates  or  enzymes  

#4- Nucleic Acids •  Form genes and take part in

protein synthesis •  2 Kinds: -DNA (Deoxyribonucleic Acid) -RNA (Ribonucleic Acid) •  Made of C, H, O, N, P •  Building block (monomer) is a nucleotide. Nucleotides are made of a sugar, phosphate, and a N base.

DNA  vs.  RNA  

•  DNA  is  double  stranded  •  Contains  the  sugar            deoxyribose  •  Has  nitrogen  bases  called          adenine  (A)    cytosine  (C)          thymine  (T)    guanine  (G)  

•  RNA  is  a  single  strand  •  Contains  the  sugar            ribose  *    Has  nitrogen  bases  called            adenine  (A)    cytosine  (C)            Uracil  (U)            guanine  (G)    

 substrate

Ac8ve  site

 enzyme

products

 

ENZYME PRACTICE

1. Label the diagram with these terms: products, active site, enzyme, substrate

2. Answer true of false to the following statements:

a. _______ One enzyme can be used for many different types of chemical reactions. b. _______ Enzymes are used only once because they change shape after a reaction occurs. c. _______ Enzymes speed up reactions. d. _______ Raising the temperature will not change the rate of a reaction that uses an enzyme e. _______ Enzyme require specific pH levels.

F  F  

F  T  

T  

ATP  ADP  and  

Energy!!!    

40  

41

Releasing Energy From ATP •  ATP is constantly being used and remade by cells

•  ATP provides all of the energy for cell activities

•  The high energy phosphate bonds can be BROKEN to release energy

42

Releasing Energy From ATP

•  Adding A Phosphate Group To ADP stores Energy in ATP

•  Removing A Phosphate Group From ATP Releases Energy & forms ADP

Loose

Gain

43

Cells Using Biochemical Energy Cells Use ATP For: •  Active transport •  Movement •  Photosynthesis •  Protein Synthesis •  Cellular respiration •  All other cellular reactions

____________   __________   ___________________  

SecMon  8-­‐1  

ATP

Go  to  Sec8on:  

Adenine   5-­‐carbon  sugar   Phosphate  Groups  

-­‐  Adenosine  Triphosphate  

44  

+  

45  

Energy  

+  

How  energy  is  released?    

A  phosphate  is  removed  by  breaking  the  bond  between  the  second  and  third    

phosphate-­‐releasing  ENERGY!  

Importance of ATP

o Energy  storage  chemical  for  cell  processes  

o Most  of  ATP  is  produced  via  electron  transport  chain    

o Main  reason  that  cells  need  oxygen:  to  allow  them  to  make  lots  of  ATP  

o Involved  in  both  photosynthesis  and  respira8on      

Photosynthesis  

Photosynthesis

6 CO2 + 6 H2O + Sunlight à C6H12O6 + 6 O2 Carbon Dioxide + Water + Sunlight à Glucose + Oxygen

49

Factors  AffecMng  the  Rate  of  Photosynthesis  

•  Amount  of  available  water  

•  Temperature  •  Amount  of  available  light  energy  

Photosynthesis  has  2  stages:  1.  Light  Dependent  Reac8on              *happens  in  the  thylakoids  (grana)  •  Uses  light  energy  •  Produce  Oxygen  from  water  •  Convert  ADP  to  ATP  2.  Light  Independent  Reac8on              Also  known  as  the  Calvin  Cycle  or  Dark              Reac8on              *  happens  in  the  open  area  called  the  stroma      

51

Photosynthesis Overview Capturing  sunlight  happens  in  the  chloroplasts  

 All  cells  carry  on  some  form  of  cellular  respiraMon.    Most  plants  and  animals  require  oxygen.          

Cellular  Respira8on  

C6H12O6  +  6  O2  à  6  CO2  +  6  H2O  +  38  ATP    Glucose  +  Oxygen  à  Carbon  dioxide  +  Water  +  Energy  

Cellular  Respira8on  

Takes  place  in  the  mitochondria  

3  Stages  of  AEROBIC  (with  oxygen)  RespiraMon  

How much energy does cellular respiration produce???

1) Glycolysis: Produces 2 ATP per Glucose

2) Krebs Cycle =2 ATP 3) Electron Transport Chain: 32 ATP

molecules per Glucose

Grand Total = 36 ATP

What happens if oxygen is not available after glycolysis???

•  Instead of pyruvic acid entering the mitochondria, fermentation occurs in the cytoplasm

•  It is known an anaerobic respiration

•  There are 2 types: Alcoholic Lactic Acid

Compare  Photosynthesis  and  Cellular  Respira8on  

Where Does it occur? Photosynthesis

–  Chloroplasts        Cellular  Respira8on  

-­‐-­‐Mitochondria  

When does it occur? Photosynthesis

–  Daylight Hours          Cellular  Respira8on  

     -­‐-­‐  At  all  8mes  

Reactants (what you start with)

Photosynthesis –  Carbon dioxide –  Water

     Cellular  Respira8on            -­‐-­‐  Glucose  (sugar)              -­‐-­‐    Oxygen  

Oxygen

Products (what you end with)

Photosynthesis –  Glucose (sugar)

Cellular  Respira8on  -­‐-­‐Chemical  energy  =  ATP  

Oxygen

THE  END