PHOTOSYNTHESIS & CELLULAR RESPIRATION
Chapters 6 & 7
1. During photosynthesis, cells of plants & some microorganisms known as
autotrophs trap energy & store it in glucose molecules for future use.
2. Later during cellular respiration, cells of both autotrophs & heterotrophs will
convert this energy into usable molecules of adenosine triphosphate (ATP)
that can be quickly & easily released to accomplish such tasks as growth,
repair, movement, & reproduction.
3. Basic facts about photosynthesis:
a) occurs in chloroplasts of autotrophic cells
b) the pigment chlorophyll captures radiant energy from sunlight
c) glucose molecules are created from carbon dioxide taken from air &
water taken from the soil
d) energy is stored in the chemical bonds of glucose molecules
e) oxygen given off as by-product
4. Chemical equation for photosynthesis:
chlorophyll
carbon dioxide + water + sunlight ----------------> glucose + oxygen
enzymes
5. Basic facts about cellular respiration:
a) ATP is composed of 1 adenosine molecule & 1 ribose sugar molecule with
3 phosphate groups attached
b) begins with glycolysis, which takes place in the cytoplasm & ends in the
mitochondria of all cells
c) requires oxygen taken from air (aerobic respiration)
d) water & carbon dioxide given off as by-products
e) stored energy is released from glucose when chemical bonds are
broken in ATP molecules (adenosine triphosphate) (ATP -> ADP ->
AMP)
6. Chemical equation for respiration:
enzymes
glucose + oxygen ---------------> water + carbon dioxide + ATP
7. When cells are without oxygen, an anaerobic process called fermentation
produces ATP molecules. (anaerobes or temporary lack)
a) alcoholic fermentation - for example, yeast cells produce carbon dioxide
ethyl alcohol as by-products of respiration - when yeast is used in making
bread, the carbon dioxide forms bubbles in the dough & cause it to rise
b) lactic acid fermentation - lactic acid is a by-product of respiration in
muscle cells during exercise - its build up causes muscle fatigue