mcgeeshsscience

 

Energy Review Notes

Page history last edited by Karen McGee 1 yr ago

Energy Review

 

*Compare and Contrast the structure & function of the

  mitochondria & chloroplasts*

 

Compare:

ØBoth are organelles that are the site of energy

   conversion pathways

ØBoth use electron transport chains to transfer

   energy to a usable form

ØBoth form some ATP

ØBoth are organelles with membranous interiors for

   the electron transport chain

 

ØThe chloroplast is the site of photosynthesis

ØThe mitochondrion is the site of respiration

ØThe chloroplast absorbs light energy using

   chlorophyll

ØThe mitochondrion releases energy from glucose

ØThe chloroplast makes glucose

ØThe mitochondrion uses glucose

ØThe chloroplast is found only in autotrophs

   (plants)

ØThe mitochondrion is found in both autotrophs

    and heterotrophs

 

*Compare and contrast aerobic and anaerobic respiration*

 

ØBoth release energy from glucose

ØBoth start with glycolysis

ØBoth form ATP

  

Contrast:

 

ØAerobic respiration uses oxygen as the final

   electron acceptor

ØAnaerobic uses something other than oxygen

   as the final electron acceptor, usually an organic

   compound

ØAerobic respiration produces more usable energy

   than anaerobic – usually 36 ATPs vs. 2 ATPs

  

*Compare and contrast cellular respiration and photosynthesis*

 

Compare:

 

ØBoth are energy conversion pathways

ØBoth use some ATP

ØBoth form some ATP

ØBoth use coenzymes

ØBoth use electron transport chains to transfer

   energy

ØBoth occur in photosynthetic autotrophs

Contrast:

 

 

ØPhotosynthesis uses energy to make glucose

ØRespiration uses glucose to release energy

ØPhotosynthesis occurs in the chloroplast

ØRespiration occurs in the mitochondrion

ØThe products of respiration are the reactants of

    photosynthesis

ØThe products of photosynthesis are the reactants

    of respiration

ØPhotosynthesis does not occur in heterotrophs

ØRespiration occurs in heterotrophs and autotrophs

ØPhotosynthesis uses the coenzyme NADP

ØRespiration uses the coenzymes NAD & FAD

ØPhotosynthesis is  an endergonic reaction

ØRespiration is an exergonic reaction

ØPhotosynthesis:  6CO2 + 6H2O + sunlight       C6H12O6 + 6O2

                                  carbon   water   energy          glucose    oxygen

                                  dioxide

ØRespiration:  C6H12O6 + 6O2           6CO2 + 6H2O + ATP

                            glucose     oxygen      carbon   water    energy

                                                               dioxide

 

 

*Describe and model the conversion of light energy to chemical energy by photosynthetic organisms:*

 

 

Photosynthesis Equation

 

6CO2    +   6H2O   + sunlight        C6H12O6    +   6O2

 carbon                water           energy              glucose                  oxygen

dioxide

Light dependent reactions

 

 

Occur in the grana of the chloroplast.  Grana are

stacks of membrane sacs called thylakoids. The

thylakoids contain the pigment chlorophyll.

Chlorophyll molecules are grouped into photosystems.

 

 

Steps of the Light Dependent Reactions

 

 

1.Solar energy splits the water molecule.

2.Chlorophyll molecules of photosystem II absorb solar

     energy. 

3.The excited electrons are bounced to higher

    energy levels.

4.Electrons are returned to the lower energy level of

    photosystem I by an electron transport chain in the

    thylakoid membrane.

5.The electrons of photosystem from photosystem I

    are picked up by NADP.

    NADP also picks up hydrogen ions; NADP is a

    hydrogen acceptor and an electron acceptor.

6.When NADP picks up hydrogen  ions it forms NADPH.

     NADPH is an energy source for the light independent

     reaction.

 

 

7.Electrons from water replace those lost from

    photosystem II.

8.As hydrogen ions move through the thylakoid

    membrane they cause the phosphorylation of

    ADP into ATP using the enzyme ATP synthase.

9.The ATP is an energy source for the light

    independent reaction.

 

 

Steps of the Light Independent Reactions (Calvin Cycle, C3 Cycle)

 

occurs in the stroma

 

1. CO2 binds with a 5 carbon sugar called

      ribulose biphosphate (RuBP)

2.  RuBP accepts carbon dioxide by using the

      enzyme rubisco and forms a 6 carbon

      molecule

3. The 6 carbon molecule splits into two 3 carbon

     molecules called PGA (phosphoglyceric acid)

4.  PGA is converted to PGAL

    (phosphoglyceraldehyde) using energy from

    ATP and NADPH from the light-dependent

    reaction.  NADP is free to be used again.

5.  PGAL forms glucose and more RuBP

 

 

 

 

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