The site of photosynthesis
Although, leaves are the main sites of photosynthesis in most plants, it can take place in any part that is green. These green parts have chloroplasts,which contain all the biochemical machinery necessary for the light-dependent and light-independent stages of photosynthesis.
Chloroplasts act as compartments, isolating the photosynthetic reactions from other cellular activities. Each chloroplast consists of two membranes enclosing a gelatinous matrix called the stroma. The stroma contains ribosomes, circular DNA, and enzymes used in photosynthesis. Suspended in the stroma are thylakoids. These are disk-like membrane sacs, several of which are stacked in a group to form a granum (plural grana). The space inside each thylakoid in a stack is connected with the other thylakoids in the stack, forming a continuous fluid-filled compartment called the thylakoid space. The thylakoid membranes contain photosynthetic pigments, including chlorophyll.
■ Glossary of essential terms for you to know
| № | English term | Russian equivalent |
| ingestion | прием пищи | |
| digestion | переваривание пищи | |
| alimentary canal | пищеварительный тракт | |
| raw | сырой | |
| to enable | давать возможность | |
| to take place | происходить | |
| to convert | превращать | |
| substrate | питательная среда | |
| starch | крахмал | |
| storage | накопление, хранение | |
| complex | сложный | |
| a waste product | продукт отхода | |
| entirely | полностью | |
| site | место | |
| to enclose | окружать |
■ Your Essential Assignments
I. Quick check:
1. During photosynthesis, what gas is:
a.raw material
b. product?
2. Give the precise location in a typical terrestrial plant of:
a.the light-dependent stage
b. the light-independent stage of photosynthesis.
II. Fill in the missing words:
| Term (verb) | Noun | Adjective |
| react | ....... | ....... |
| accumulate | ....... | ....... |
| produce | ....... | ....... |
| require | ....... | ....... |
| connect | ....... | ....... |
III. Use monolingual English dictionary and write down what could the words given below mean:
plant, leave, ingredient, substance, raw, energy.
IV. Match these words with their definitions:
| Photosynthesis | A. | a type of solid or liquid that has particular characteristics | |
| Chlorophyll | B. | natural light that comes from the sun | |
| Substance | C. | one of several good substances such as sugar which consist of oxygen, hydrogen, and carbon and which provide your body with heat and energy | |
| Soil | D. | the green substance in leaves | |
| Respiration | E. | one of the many substances that exist in food such as meat, eggs, and beans, which help your body to grow and keep it strong and healthy | |
| Waste | F. | a chemical substance produced by living cells in plants and animals, that causes changes in other chemical substances without being changed itself | |
| 7. | Sunlight | G. | the production by a green plant of special substances like sugar that it uses as food, caused by the action of sunlight on chlorophyll |
| 8. | Glucose | H. | the smallest part of a living thing that can exist independently |
| 9. | Protein | I. | the process of breathing |
| Fat | J. | things that people and animal eat | |
| Carbohydrate | K. | a very thin piece of skin that covers or connects parts of the body | |
| 12. | food | L. | a natural form of sugar that exists in fruit |
| 13. | enzyme | M. | the top layer of the earth in which plants grow |
| 14. | cell | N. | Unwanted materials or substances that are left after you have used something |
| 15. | membrane | O. | an oily substance contained in certain foods |
V. Find English equivalents to the following word combinations:
| № | Russian term | English equivalent |
| 1. | прием и переваривание пищи | |
| 2. | пищеварительный тракт | |
| 3. | вместо… | |
| 4. | сложные вещества | |
| 5. | происходит только при свете | |
| 6. | химические реакции | |
| 7. | главная пищеварительная среда | |
| 8. | производить свою собственную еду | |
| 9. | способность растений получать энергию от солнца | |
| 10. | клеточная активность | |
| 11. | состоит из двух мембран |
VI. Give Russian equivalents to the following English terms:
| № | English term | Russian equivalent |
| to be rich in carbohydrates, proteins and fats | ||
| simple ingredients | ||
| a waste product | ||
| raw materials | ||
| external source of free energy | ||
| to be supplied by sunlight | ||
| light-dependent stage | ||
| light-independent stage | ||
| to form cell walls | ||
| complex organic substances | ||
| the main site of photosynthesis | ||
| a fluid-filled compartment |
VII. Find synonyms among the pool of words:
| Pool of words | Synonyms |
| 1)1.plant /2.substance /3. material /4.herb | |
| 2)1.digestion /2.energy /3.assimilation /4. power | |
| 3)1.obtain /2.act /3.connect /4.join /5.react /6.get | |
| 4)1.gather/2.enclose /3.surround /4.accumulate |
VIII. Answer the following questions. Use all information given before:
1. What is plant material rich in?
2. Do plants make their food for themselves?
3. What is chlorophyll?
4. What is the role of chlorophyll?
5. What process is called photosynthesis?
6. What are two main stages in photosynthesis?
7. What is the difference between light-dependent and light-independent stage?
8. What is the main site of photosynthesis in most plants?
IX. Match the sentence halves. Make complete sentences: