Photosynthesis Flashcards
the source of energy
the sun
autotrophs
organisms that can make their own food
all green plants, some bacteria, some protists
what form of energy do autotrophs use to produce food
light energy from the sun
what form is light energy produced as food
glucose or sugar
heterotrophs
organisms that cannot make their own food
all animals and all fungi
how do heterotrophs gain energy
by consuming food
what form does energy enter the ecosystem
sunlight
what do plants use the suns energy to make
glucose
photosynthesis
- converting radiant energy (from the sun) into chemical energy (as glucose)
- convert water & carbon dioxide into high-energy sugar molecules
Name & Energy Level
ATP
- Adenosine Triphosphate
- Energy Rich
Name & Energy Level
ADP
- Adenosine Diphosphate
- Energy Poor
Structure of ATP
- Adenine, a nitrogen base
- Ribose, a 5-carbon sugar
- A chain of three phosphate groups
ADP -> ATP
Adding a phosphate
* when a cell has energy available it can store small amounts by adding a phosphate group
Storing Energy
Add a phosphate
ATP -> ADP
Removing a phosphate
* when a cell needs energy, the third phosphate will be removed
Releasing Energy
Removing a phosphate
What does ATP power?
- Photosynthesis
- Protein Synthesis
- Muscle Contractions
- Active Transport
Basic Energy Source
ATP
How much ATP is consumed & regenerated in a second?
10,000,000
waste product of photosynthesis
oxygen
What is life on earth dependent on photosynthesis for?
food & oxygen
The Photosynthesis Equation
6CO2 + 6H2O + Sunlight = C6H12O6 + 6O2
How do plants take in CO2?
Through their leaves
How do plants take in H2O?
Through their roots
What does photosynthesis require?
- water
- carbon dioxide
- light energy
- chlorophyll
electromagnetic spectrum
the range of energy radiated outward from the sun
what does the atmosphere act as?
a selective window that allows visible light to pass through while screening out a substantial fraction of other radiation
What drives photosynthesis?
the visible light from radiation
the colors of the visible spectrum are
red, orange, yellow, green, blue, indigo, violet
pigment
any substance that absorbs light
how do plants absorb the suns energy?
via pigments (light absorbing)
different pigments…
…absorb light of different wavelengths
what happens to the absorbed wavelengths?
they disappear
is there an alternate to absorbing wavelengths?
yes, reflecting them
the colors we see are being reflected by a pigment
principal photosynthetic pigment
chlorophyll
chlorophyll
a green pigment contained in chloroplasts
What can chlorophyll absorb?
All colors of the visible spectrum except for green. It reflects green.
So, its green to us
What wavelengths of light are best absorbed by chlorophyll?
~425nm and ~660nm
What wavelengths of light are least absorbed by chlorophyll?
~450nm and ~650nm
chlorophyll-a
blue-green
chlorophyll-b
yellow-green
what happens when chlorophyll absorbs light?
energy transfers directly to electrons
these high-energy electrons make photosynthesis work
major organ of photosynthesis
leaves
what are leaves the major organ of
photosynthesis
how many chloroplasts per sqmillimeter of leaf?
~500,000
Cuticle
A waxy covering on the upper & lower surface of a leaf that helps prevent water loss
Mesophyll
- central middle area
- contains palisade cells & spongy cells (both of many chloroplasts)
- the palisade layer is the primary photosynthetic layer
Stomata
- pores in the leaf (for CO2 to enter and oxygen to exit)
- the opening into the leaf
- guard cells found on either side (they’re like the doors)
- source of water loss
- usually found on the lower surface (to help reduce water loss)
vascular bundles
- contains xylem and phloem
- xylem carries water up the plant, brings water to the leaf
- phloem carries food down the plant, glucose will exit through the phloem and get carried to other parts of the plant
chloroplast membrane
double membrane - there is a space between them
thylakoids affect on the chloroplast
- make a third membrane system
- big stacks of thylakoids are called grana
- they contain chlorophyll
What is surrounding of the thylakoid?
a dense solution called, the stroma
What are Thylakoids
the structural unit of photosynthesis
what form do thylakoids take
the form of flattened sacs or vesicles
What molecules are built into the thylakoid membrane
chlorophyll molecules
what do chlorophyll molecules do?
capture light energy
where does photosynthesis take place??
in the chloroplast