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Flashcards by ashiana121, updated more than 1 year ago
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Created by ashiana121
almost 10 years ago
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| Question | Answer |
| Which part of the plant is the main photosynthetic structure? | The leaf |
| What is the name of the cellular organelles within the leaf where photosynthesis takes place? | Chloroplasts |
| The leaf has many adaptations that make it suited to photosynthesis. One of these is a ______ surface area that collects as much sunlight as possible | Large |
| Also, the arrangement of the leaves on the plant minimises ____________ and avoids the shadowing of one leaf by another | Overlapping |
| How is the fact that leaves are thin make them well adapted for photosynthesis? | Most light absorbed in the first few millimetres Diffusion distance kept short |
| A transparent _______ and epidermis that let light through to the photosynthetic mesophyll cells beneath | Cuticle |
| Long, narrow upper mesophyll cells packed with ____________ that collect ________ | Chloroplasts that collect sunlight |
| Numerous _______ for gaseous exchange | Stomata |
| Stomata that open and close in response to _____ _________ | Light intensity |
| Many ___ _______ in the lower mesophyll layer to allow diffusion of carbon dioxide and oxygen | Air spaces |
| A network of _____ that brings water to the leaf cells | Xylem |
| ______ that carries away sugars produced by photosynthesis | Phloem |
| What are the three main stages to photosynthesis? | 1. Capturing of light energy 2. The light dependent reaction 3. The light independent reaction |
| In the light DEPENDENT reaction, light energy is converted into what type of energy? | Chemical energy |
| In the light INDEPENDENT reaction, the protons from the LD are used to _______ carbon dioxide to produce sugars and other organic molecules | Reduced |
| What are the two distinct regions with a chloroplast? | Grana Stroma |
| What are the grana? | Stacks of disc like structures called thylakoids |
| What stage of photosynthesis takes place in the grana? | Light-dependent |
| Within the thylakoids is the photosynthetic pigment called... | Chlorophyll |
| What is the stroma and what stage of photosynthesis takes place there? | A fluid filled matrix where the independent stage of photosynthesis takes place |
| What other structures may be found in the stroma? | Starch grains |
| In how many ways is the light energy captured used in the light dependent reaction? | 2 |
| What are these ways? | - To add Pi to ADP making ATP - To split water into H+ ions and OH- ions |
| What is used to split the water? | Light |
| What name is given to this process? | Photolysis |
| When a substance is combined with oxygen it is called _________ | Oxidation |
| When a substance is oxidised it loses ________ | Electrons |
| When a substance is ________ it gains electrons | Reduced |
| In how many ways can something be oxidised/reduced? | 3 |
| Reduction | 1. Gain of electrons 2. Gain of H+ 3. Loss of oxygen |
| Oxidation | 1. Loss of electrons 2. Loss of H+ 3. Gain of oxygen |
| What happens when a chlorophyll molecule absorbs light energy? | It boosts the energy of a pair of electrons within the chlorophyll, raising them to a higher energy level |
| These electrons are said to be in an ________ _____ | Excited state |
| In fact, the electrons become so energetic that they... | Leave the chlorophyll molecule |
| What are these electrons taken up by? | An electron carrier molecule |
| The chlorophyll molecule has become _________ | Oxidised |
| The electron carrier has been _______ | reduced |
| The electrons are now passed along a chain of electron carriers in a series of _________-_________ reactions | Oxidation-reduction |
| Where is this transfer chain located? | The membrane of the thylakoid |
| Why do electrons lose energy as they travel down the chain? | Each new carrier is at a slightly lower energy level |
| What is this energy used to do? | ADP + Pi ---> ATP |
| The loss of electrons when light hits the chlorophyll molecule leaves it short of electrons. What does this mean needs to happen? | The electrons need to be replaced if the chlorophyll molecule is to continue absorbing light energy |
| Where are these electrons provided from? | Water molecules that are split using light energy |
| What does this photolysis of water also produce? | H+ (protons) |
| What is the equation for the photolysis of water? | 2H20 ---> 4H+ + 4e- + O2 |
| What are the protons taken up by? | NADP |
| What does NADP then become? | Reduced NADP |
| What does reduced NADP enter? | The light independent reaction |
| Why is the reduced NADP important for the plant? | It is a further source of chemical energy |
| What happens to the oxygen by-product of the photolysis of water? | - Used in respiration - Diffuses out as a waste product |
| The chloroplasts are adapted for their function in catching sunlight and carrying out the LD reaction. How? (1. surface area) | Thylakoid membranes provide a large s.a for the attachment of enzymes, chlorophyll and electron carriers |
| How does the network of proteins in the grana make the chloroplasts well adapted? | They hold the chlorophyll in a very precise manner that allows maximum absorption of light |
| The granal membranes have _________ attached to them, which help manufacture what? | Enzymes that help manufacture ATP |
| Chloroplasts contain both ___ and _________ so they can quickly and easily manufacture some of the proteins needed for the LD reaction | DNA and ribosomes |
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