Week 10 – Review and revision of photosynthesis, secondary thickening and pollination/fertilization
RHS Level 2 Certificate
Week 10 – Revision week.
Photosynthesis and respiration review
Pollination – cell division in pollen germination
To identify the end product and waste product of photosynthesis
To state the equation for photosynthesis in words
To describe the light dependent and light independent phases of photosynthesis in overview
To state the limiting factors of photosynthesis
To state the equation for respiration in words
To identify the end product and waste products of respiration
To identify the tissue involved in secondary thickening
To describe the process of secondary thickening
To define pollination
To describe the process of fertilization
Why does a leaf look green?
High energy electrons are passed through the electron chain and the energy is used to split molecules of water (H2O) into their component hydrogen and oxygen. The oxygen is released as a by-product into the atmosphere. The energy released by breaking the chemical bonds in the water is incorporated, with the hydrogen, into energy carrying molecules called ATP and NADPH2.
If a process is influenced by more than one factor, the rate of the process will be limited by the factor that is in lowest supply
Therefore if temperature is low (10 °C) increasing light intensity or carbon dioxide concentration will not increase the rate of photosynthesis.
Why does this matter ? The slower the rate of photosynthesis the slower the rate of growth.
plateau At low CO 2 concentration, rate is positively correlated with concentration CO 2 is a substrate in an enyme-catalysed light-dependent reaction.
At low light intensity, rate of photosynthesis is proportional to light intensity. plateau
Increased temp. gives increased energy and increased rate of photosynthesis Optimum temperature Above the optimum temp., enzymes are denatured and rate drops steeply. Which enzymes are used in respiration?
Process of Cellular Respiration
Food (glucose) is broken down using oxygen into CO 2 and H 2 O and energy is released
This takes place in the mitochondria
Carbohydrate plus oxygen carbon dioxide plus water plus energy
C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + energy (ATP)
This energy can be stored (as ATP) - to be used later for things like growth
Occurs in perennials
A ring of vascular cambium produces secondary xylem and phloem
Wood is the accumulation of these secondary tissues, especially xylem