Biology Plant Physiology (PP 1-8 and IV)

PP 1

PP 1: PHOTOSYNTHESIS

Photosynthesis: The process by which plants make food combining carbon dioxide and water to make glucose using light energy captured using chlorophyll.

Word equation:

                                       (Chloroplast) 

Carbon dioxide  + Water  ------------->  Glucose + oxygen

                                      (LIght energy)

Symbol equation:

6CO₂  + 6H₂O è C₆H₁₂O₆ + 6O₂

Glucose:

•   Respiration provides energy to survive

•   Starch (storage)

•   Cellulose (Cell wall)

PP 2: Structure of a leaf

From top to bottom of the leaf:

•   Upper epidermis

•   Cuticle

•   Palisade mesophyll

•   Vein xylem

•   Vein Phloem

•   Spongy mesophyll

•   Lower epidermis

•   Guard cells

•   Stoma (pore)

Cells that are capable of photosynthesis: palisade mesophyll, Guard cells and the spongy mesophyll. This is because they all have Chloroplast.

PP 3 STOMATA

Stomata play a very important role in the life of a plant. they allow carbon dioxide and oxygen to diffuse in and out of the leaves. They are also the main route by which water vapour escapes from the plant. In hot weather it is important that the stomata stops water vapour from escaping. They do this by closing. The guard cells on either side of the stomata lose water and cal apes causing the gap to be closed. To open again the guard cells fill with water and bend, opening the gap between the two guard cells.

PP 5 FACTORS THAT AFFECTS PHOTOSYNTHESIS

There are three

•   Light

•   Carbon dioxide

•   Temperature

PP 7 MINERAL DEFICIENCIES

•   Magnesium deficient: would turn the leaf yellow.

•   Nitrate deficient: would make the plant short.

•   Phosphorus deficient: would make the leafs turn purple.

PP 8 OSMOSIS

Equilibrium: It means equal, there are the same amount of salt and water particles on either side.

Hypertonic: Having a higher osmotic pressure in a fluid

Hypotonic: Having a lower osmotic pressure

Osmosis: osmosis is the passage of water from an area of high concentration (water molecules) to area of low concentration through a parochially permeable membrane.

PP 12 TRANSPIRATION

Transpiration: is the evaporation of water format he leaves of plants. The water is drawn up from the roots in the soil and is "sucked" up the xylem vessels in the stem all the way to the leaves. Water evaporates form the stamata, which can open during the day and close at night.

Environmental conditions affect on transpiration

• Cold: Decrease
• Hot: Increase
• Dry: Increase
• Humid: Decrease
• Windy: Increase

PP 14 PHOTOTROPISM

Phototropism: a growth response of a plant to the direction of light.