Photosynthesis Lesson 1 – review lesson for structure of a leaf and how its adapted for photosynthesis

Complete worksheet using keywords Settling activity Complete worksheet using keywords

Learning outcomes Success criteria By the end of this lesson I will know – How leaves are adapted to bring together raw materials (water, carbon dioxide and light) for photosynthesis and remove its products (oxygen and glucose) That chloroplasts membranes have 2 distinct regions; thylakoids – are where the light dependent stage will take place and the stroma – where the light independent stage of photosynthesis will occur I will achieve these outcomes by- Labelling a diagram of a leaf and chloroplasts

INTERGRANAL LAMELLAE

Starter Label the diagram of a chloroplast Extension – Write down 2 specific reasons why photosynthesis is important to us. Existence Energy from food or when burning wood. Coal etc Produces oxygen

Chloroplasts Disc shaped 2-10 um long 1 um in diameter Double membrane Inside membranes Grana – 100 disc thylakoids stacked up - in thylakoids there is the pigment chlorophyll. - Light dependent stage of photosynthesis Stroma - fluid filled matrix - within stroma are a no. of starch grains - Light independent stage of photosynthesis

Structure of a leaf Large surface area for light absorption Label the diagram – how is the leaf adapted to maximise photosynthesis. Large surface area for light absorption Leaves are arranged to minimise overlapping Thin – short diffusion distance Transparent cuticle/epidermis – light can pass through to photosynthetic mesophyll cells Long narrow upper mesophylls packed with chloroplasts Lots of stomata for gas exchange Stomata open/close depending on light intensity Air spaces in lower mesophyll to allow diffusion of oxygen and carbon dioxide Xylem network brings water to the leaf Phloem carries sugars

Oxidation and reduction Oxidation and reduction always occur together. These two process are important in the understanding of photosynthesis. Write down 2 things you understand by the word oxidation. When a substance combines with oxygen = oxidation. This substance has been oxidised. O I L R I G What do you understand by this?

O xidation I s L oss of electrons / hydrogen (gain of oxygen/energy given out) R eduction I s G ain of electrons / hydrogen (loss of oxygen/energy in)