exam questions
Cards (18)
- Name the organelle that fixes carbon dioxide from the atmosphere (1)- Chloroplasts
- Where in the chloroplasts the light-dependant reactions take place (1)Thylakoids (found in the grana)
- State the location of chlorophyll in a chloroplast (1)- Thylakoid membrane/grana
- In which part of the chloroplast does the light-independent reactions take place (1)- Stroma
- Explain the relationship between the structure and functions of a granum in photosynthesis (3)- Granum is formed from many layers of thylakoid membranes to increase surface area for absorbing light- As the thylakoid membranes contain chlorophyll to absorb light- for light dependant reaction- Electron carrier molecules in thylakoid membrane involved in ATP production
- describe the light independent reaction of photosynthesis (5)
- use of light energy to excite electrons in chlorophyll
- photolysis of water to produce oxygen, electrons and hydrogen ions
- electrons used in the ETC to replace those by by chlorophyll
- generation of ATP/photophosphorylation
- reduction of NADP
- Where does the light dependant stage take place? (1)- Thylakoids
- What are the products of the light dependant reaction (1)- Oxygen, reduced NADP, ATP
- Describe the light dependant reaction (5)- save my exams
- Light energy excites electrons+ raises electrons to a higher energy level
- Electrons are passed along the electron transport chain AND release energy
- (Energy is used to) pump hydrogen ions across the thylakoid membrane (which then diffuse back again via ATP synthase)
- (Energy is used to) phosphorylate ADP / produce ATP from ADP and Pi
- Light energy photolysis/splits water molecules into protons AND electrons AND oxygen
- NADP is reduced / reduced NADP/NADPH is produced
- Aside from the general effect of cold temperatures on enzyme-controlled reactions, explain why extreme cold leads to a decrease in the rate of the light independent reactions (2)- There is less/no ATP being produced by the light-dependant reaction- No reduced NADP from the light dependant reaction
- Describe how starch is formed from the products of the light independent reactions of photosynthesis (4)- 1 carbon molecule from 2x GALP used to form glucose molecule, 6 cycles of the Calvin cycle for 1 glucose molecule- Glucose molecules join 1,4 glycosidic bonds and 1,6 for amylopectin only- Occurs via a condensation reaction- Producing amylose and amylopectin
- Explain why increase in C02 concentration affects the growth of plants in glasshouses (3)- Carbon dioxide is the limiting factor- Carbon is fixed with RuBP to produce GP and then into GALP- Thus, more carbon dioxide means more glucose is being produced and amino acids- Which would lead to greater rate of growth
- Name 2 immediate products from the light dependant stage (2)- GALP and GP
- Describe the roles of the products of the light dependant reactions in the Calvin cycle (3)- ATP provides energy and reduced NAPH provides hydrogens for the reduction of GP into GALP- ATP also used in the regeneration of RuBP- converting GALP to RUBP
- Explain the importance of RUBISCO to the productivity of an ecosystem (2)- Fixes inorganic carbon/ CO2 (combines RuBP with CO2)- Allowing formation of organic molecules by the carbon cycle e.g., glucose- These organic molecules allow transfer of energy to next trophic level
- Explain how glucose can be used in the plant- Can enter respiration to release energy- Can be converted into starch for storage- Can be converted into cellulose for cell wall structure- Can be converted into sucrose for transport
- A decrease in the activity of rubisco limits the rate of photosynthesis, why? (2)- Less RuBP and C02 are combining- Less GP and GALP produced so no regeneration of RuBP
- Explain what is meant by fixation of carbon dioxide (3)- Removal of carbon dioxide from the air- Carbon atoms from carbon dioxide are incorporated into organic material- Catalysed by enzyme rubisco- To build up plant’s biomass/cells/tissues