KCSE Photosynthesis — practice questions
71 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice KCSE Photosynthesis in the app →Which three groups of organisms are the only ones capable of performing photosynthesis?What name is given to an organism capable of producing its own organic compounds from sunlight?How do chemoautotrophic bacteria obtain the energy they need to synthesise sugars?What proportion of Earth's ecosystems is powered by photosynthesis?Roughly how long ago was the sunlight energy stored in the coal and petroleum burned today captured by photosyWhich three substrates does photosynthesis require?Which simple carbohydrate is produced by photosynthesis and can later be converted into glucose or sucrose?In which layer of the leaf does photosynthesis occur?Why are stomata typically found on the underside of a leaf?How do guard cells open and close a stoma?How many membranes make up the envelope of a chloroplast?What is a stack of thylakoids inside a chloroplast called?What is the internal space enclosed by the thylakoid membrane called?Which part of the chloroplast is the fluid-filled space surrounding the grana?Into which two sequential stages is photosynthesis divided?Why can the light-independent reactions not run indefinitely in the dark, even though they do not use light asHow does photosynthesis take place in prokaryotes such as cyanobacteria, which have no chloroplasts?What is measured from one crest of a wave to the next consecutive crest?How is the energy carried by electromagnetic radiation related to its wavelength?Why can X-rays and ultraviolet rays harm living organisms?What happens to a pigment molecule struck by light of energy higher than that of blue light?Over which wavelength range do plant pigment molecules absorb light, a range called photosynthetically active Which colours of visible light have the shortest wavelengths and therefore the highest energy?Why does a pigment appear to be a particular colour?Which two major classes of photosynthetic pigments are found in plants and algae?How many major chlorophylls are there, apart from the related prokaryotic molecule?What is the role of carotenoids in photosynthesis?Why does chlorophyll appear green to the eye?Which wavelengths do carotenoids absorb, and which do they reflect?Which pigment is described as an accessory pigment that absorbs blue and red-orange light?Which instrument measures transmitted light and computes the absorption of a pigment sample?On what basis does chromatography separate plant pigments?What is the overall function of the light-dependent reactions?Where are the two types of photosystem found?On what basis do the two photosystems differ from each other?What does the light-harvesting complex of a photosystem do?Roughly how long does the captured energy take to reach the reaction centre after a chlorophyll is excited?What is a photoact?The cytochrome complex transfers electrons between which two carrier molecules?P680 is the name given to which structure?Where does photosystem II obtain the electron that replaces the one it has given up?What is released when one water molecule is split at photosystem II?What proportion of the oxygen produced by a leaf is used by its own mitochondria?In which direction are hydrogen atoms moved as electrons travel between photosystem II and photosystem I?Why must a second photon be absorbed at photosystem I?Which product does photosystem I capture the energy to make?Which statement correctly describes photosystem II?In which direction do hydrogen ions diffuse when adenosine triphosphate is made in the chloroplast?What is the name of the flow of hydrogen ions through the protein channel of the thylakoid membrane?Which pigment sits in the reaction centre that a photon reaches after striking the antenna pigments of photosyHow do the lifespans of the light-dependent products compare with those of the light-independent products?Where in the plant cell do the light-independent reactions take place?Why is the term dark reactions considered misleading?What alternative name includes the second scientist involved in discovering the light-independent reactions?Into which three basic stages are the light-independent reactions organised?Which enzyme catalyses the reaction between carbon dioxide and the five-carbon acceptor in the stroma?How is the molecule ribulose bisphosphate built?How many molecules of 3-PGA form from a single turn of the cycle, and how is each one built?What is carbon fixation?In the reduction stage, six molecules of 3-PGA are converted into six molecules of which compound?What is meant by a reduction reaction?How many molecules of adenosine triphosphate and NADPH are used in the reduction stage?What happens to the energy carriers once they have been spent in the reduction stage?Of the six molecules made after three turns of the cycle, how many leave and how many stay?How many extra molecules of adenosine triphosphate are used in the regeneration reactions?How many turns of the cycle are needed before a three-carbon molecule can leave to join a carbohydrate?How does modern oxygenic photosynthesis differ from the older bacterial type?Why does a plant lose water during active photosynthesis?Why do some plants such as cacti prepare materials for photosynthesis during the night?Why must a plant carry out respiration as well as photosynthesis?Which pair of statements correctly describes where each process handles carbohydrate?