Photosynthesis Flashcards
(19 cards)
What is photosynthesis?
Is the process where green plants combine water and carbon dioxide using sunlight energy, to produce glucose and the by-product oxygen
What is the word equation for photosynthesis?
carbon dioxide + water
—sunlight energy/chlorophll—>glucose + oxygen
What is the chemical equation for photosynthesis?
6CO2 + 6H2O —–sunlight energy/chlorophyll—> C6 H12 O6 + 602
What is autotroph?
'’self-feeders’’
e.g plants that make their own food during photosynthesis
What is Heterotroph?
'’feed on other organisms’’
e.g consumers that feed on plants and other animals
What is Saprophyte?
'’feeds on dead organic material’’
e.g decomposers that feed on the dead autotrophs and heterotrophs
What are the 2 stages of photosynthesis?
Light stage (light-dependent stage)
Dark stage (light-independent stage)
What happens in the light stage?
Sunlight energy enters the leaf and splits the water molecules into hydrogen and oxygen. This is called ‘‘photolysis’’.
What is the chemical equation for Photolysis?
H2O + sunlight/energy ——-> 2H + O
What happens in the dark stage?
the hydrogen from the light stage, will combine with the carbon dioxdie gas to make glucose. The dark stage can also occur in either light or darkness.
What is the chemical equation for the dark stage?
-6CO2 +6H2—> C6 H12 O6 + 3O2
What are the products of photosynthesis?
glucose- main product
oxygen- by-product
What happens to the products of photosynthesis?
-the oxygen produced by photosynthesis will diffuse into the atmosphere for animals to breathe
-the glucose produced by photosynthesis is stored as starch grains in the chloroplasts
What are the adaptations of a leaf?
- the leaves are thin to allow light and carbon dioxide to reach all cells rapidly
- xylem vessels transport water to the leaf cells
- phloem sieve tubes carry away the food made in the leaf cells to the rest of the plant
- a waxy cuticle prevents water loss from both surfaces of the leaf
- they lie at 90 degrees to the sunglight and are spaced around the stem to catch as much light as possible.
What are the limiting factors in photosynthesis?(4)
-temperature
-light intensity
-carbon dioxide concentration
-availability of water
What is temperature?
The rate of a reaction increases as temperature increases. With heat the molecules move about, and come together faster.
What is light intensity?
The amount of light in the environment varies greatly between night and day. This is usually the limiting factor from dusk until dawn.
What is carbon dioxide concentration?
The concentration of carbon dioxide is relatively low in the atmosphere, so carbon dioxide is usually the limiting factor when temperature and light levels are high.
What is Availability of water?
The availability of water varies in the environment. If soil is dry, water may be the limiting factor on photosynthesis.
