2. LO:
• Define photosynthesis
• State the word equation for photosynthesis
• State the balanced chemical equation for
photosynthesis
• Explain the importance of chlorophyll for
photosynthesis
• Outline the subsequent use and storage of the
carbohydrates made in photosynthesis
3. • Define the term limiting factor
• Identify and explain the limiting factors of
photosynthesis in different environmental
conditions
• Describe the use of carbon dioxide
enrichment, optimum light and optimum
temperatures in glasshouses in temperate and
tropical countries
• Use hydrogencarbonate indicator solution to
investigate the effect of gas exchange of an
aquatic plant kept in the light and in the dark
4. • Identify chloroplasts, cuticle, guard cells and
stomata, upper and lower epidermis, palisade
mesophyll, spongy mesophyll, vascular
bundles, xylem and phloem in leaves of a
dicotyledonous plant
• Explain how the internal structure of a leaf is
adapted for photosynthesis
• Explain the effects of nitrate ion and
magnesium ion deficiency on plant growth
5. LO: practical work
• Investigate the necessity for chlorophyll, light
and carbon dioxide for photosynthesis, using
appropriate controls
• Investigate and describe the effects of varying
light intensity, carbon dioxide concentration
and temperature on the rate of
photosynthesis, e.g. in submerged aquatic
plants
6. VOCABULARY
• Synthesis = building up of complex molecules
from simpler substances
• Energy transducers = convertors of energy,
converting light energy into chemical energy
• Autotrophic = self-feeding
7. • Plants are autotrophic organisms – they take
simple substances from their environment and
use light energy to build them up into complex
food compounds
• Produce their own food in the process called
PHOTOSYNTHESIS
LO: Define photosynthesis
8. Photosynthesis
• Photos = light
• Synthesis = building up
= basic process by which plants manufacture
carbohydrates from raw materials using energy
from light
= is the process in which light energy, trapped by
chlorophyll, is used to convert carbon dioxide and
water into glucose and oxygen
LO: Define photosynthesis
9. Requirements for photosynthesis
• Sunlight = light energy, transported in photons
• Chlorophyll = green pigment contained in chloroplasts;
needed to absorb the energy from photons; energy
transducers – converts the light energy into chemical
energy
• Carbon dioxide from the atmosphere
• Water from the soil
• Suitable temperature
10. LO: State the word equation for photosynthesis, State
the balanced chemical equation for photosynthesis
Equations of photosynthesis
11. • Chlorophyll absorbs light energy and enables
it to be used to drive the reactions.
• Chlorophyll transfers light energy into
chemical energy in molecules, for the
synthesis of carbohydrates
• The initial products of photosynthesis are
sugars (such as glucose) which can be
converted to large, insoluble molecules such
as starch for storage within the plant
13. LO: Explain how the internal structure of a leaf is
adapted for photosynthesis
The Leaf
In order to photosynthesise a leaf needs:
• Exchange of gases
• Delivery of water
• Removal of glucose
• Obsorbtion of light energy
15. U = WAXY CUTICULE
- Reduces water loss; it is thicker on the upper
surface
P = UPPER EPIDERMIS
- One cell thick; is transpaarent; prevents the entry
of disease-causing microorganisms
V = PALISADE MESOPHYLL
- tall thin cells with small intercellular spaces; many
chloroplasts for maximum absorption of photons
16. Q & R = VASCULAR BUNDLE
– Xylem – deliver water and minerals
– Phloem – carry away the organic products
S = SPONGY MESOPHYLL
– Loosely packed cells, covered with a thin layer of
water
W = air spaces, aid the diffusion of gasses
18. LO: Explain how the internal structure of a leaf is
adapted for photosynthesis
Stomata
• Allow the entry of carbon dioxide and the exit of oxygen
• It can be closed when no carbon dioxide intake is needed
• When a plant is short in water, the guard cells become
flacid, closing the stoma
• When a plant has plenty of water, the guard cells become
turgid, swell up, curve away from each other, opening the
stoma
19. • Stomata will close:
– to conserve water at night-time when photosynthesis
can no longer continue
– if the plant is losing too much water
– in response to wounding - plants can lose a lot of
water through open wounds and some plants,
e.g. tomato plants, react rapidly to damage by
transmitting electrical signals throughout their leaves
which trigger the stomata to close
• Stomata will open and close according to a
circadian rhythm as well as in direct response to
light and dark.
23. The intake of carbon dioxide and
water by plants
• Water availability:
– A shortage of water closes stomata which limits
carbon dioxide uptake
– There is always enough water as a subtract for
photosynthesis
– The water uptake happens through the roots and
water is then transported through xylem
26. LO: Define the term limiting factor
• http://www.dnatube.com/video/11622/Facto
rs-That-Affect-Photosynthesis
• http://www.dnatube.com/video/11219/Rate-
of-a-Reaction-Affecting-Factors
27. LO: Explain the effects of nitrate ion and magnesium
ion deficiency on plant growth
Plants and minerals
• nitrate ions:
– for protein synthesis,
• magnesium ions
– for chlorophyll synthesis.
28. • Is absorbed from the soil as a nitrate ions
(NO3
-) or ammonium ions (NO4
+)
• It is required for proteosynthesis (production
of proteins)
• Deficiency: causes severe symptoms, the
whole plant is stunted, with weak stem and
yellowing, dying leaves
LO: Explain the effects of nitrate ion and magnesium ion
deficiency on plant growth
Nitrogen
29. LO: Explain the effects of nitrate ion and magnesium
ion deficiency on plant growth
Magnesium
• Is absorbed from the soil as magnesium ions
(Mg2+)
• Forms part of the chlorophyll molecule
• Deficiency causes Chlorosis = the leaves turn
yellow, usually from the bottom of the plant
first
30. Fertilisers
• Are needed to add nitrates and phosphates to
the soils
• Natural fertilisers – sewage sludge, animal
manure or compost
• Artificial fertilisers – NPK contains nitrogen,
phosphorus and potassium
31. Problems with fertilisers
• Overuse of fertilisers can cause problems of
eutrophication
• The fertiliser runs off into nearby streams,
rivers and lakes and boosts the frowth of
algae; as algae die they are decomposed by
bacteria, which use all of the oxygen dissolved
in water for aerobic respiration = result = not
enough oxygen for fish and insect
hypertrophication, is the ecosystem response to the addition of artificial or natural substances, such as nitrates and phosphates, throughfertilizers or sewage, to an aquatic system.[1] One example is the "bloom" or great increase of phytoplankton in a water body as a response to increased levels of nutrients. Negative environmental effects include hypoxia, the depletion of oxygen in the water, which induces reductions in specific fish and other animal populations. Other species (such as Nomura's jellyfish in Japanese waters) may experience an increase in population that negatively affects other species.
