27
Text 4. Energy transfers and energy transformations
«Energy cannot be created or destroyed, it can
only be changed from one form to another»
Albert Einstein
PRE-READING
Give answers to the following questions:
1. What do you know about photosynthesis?
2. Why is this process so important for the nature?
Active vocabulary
Word
Pronunciation
Translation
adenine, n.
/ˈædənin/
аденин
adenosine
/əˈdɛnəʊsɪnˈdɪfɒsfeɪt/
аденозина дифосфат/ АДФ
diphosphate/ ADP
adenosine
/əˈdɛnəʊsɪnˈtrɪfɒsfeɪt/
аденозина трифосфат/ АТФ
triphosphate/ ATP
bioenergetics, n.
/baɪəʊˌenədʒetɪks/
биоэнергетика
bioluminescence,
/ˌbaɪəʊˌluːmɪˈnɛsəns/
биолюминесценция
n.
carbohydrate, n.
/ˌkɑːbəʊˈhaɪdreɪt/
углевод
chemical, adj.
/ˈkemɪkəl/
химический
conduction, n.
/kənˈdʌkʃən/
проводимость
conversion, n.
/kənˈvɜːʒən/
переход, превращение
disorder, n.
/dɪˈsɔːdər/
расстройство, беспорядок, syn.
disarray
entropy, n.
/ˈentrəpi/
энтропия
enzyme, n.
/ˈenzaɪm/
энзим, фермент
glucose, n.
/ˈɡluːkəʊs/
глюкоза
invariable, adj.
/ɪnˈveəriəbl /
неизменный, постоянный, syn.
changeless, permanent, unvaried
linkage, n.
/ˈlɪŋkɪdʒ/
соединение, сцепление, связь
metabolic, adj.
/metəˈbɑlɪk/
метаболический, относящийся
к процессу обмена веществ
nitrogen, n.
/ˈnaɪtrədʒən/
азот
28
nucleoside, n.
/ˈnjuːkliəsaɪd/
нуклеозид
photosynthesis, n. /ˌfəʊtəʊˈsɪnθəsɪs/
фотосинтез
randomness, n.
/ˈrændəmnəs/
беспорядочность,
хаотичность,
случайный
характер
release, v.
/rɪˈliːs/
освобождать,
высвобождать,
выпускать, syn. give out, free
respiratory, adj.
/ˈrespərətɔːri/
дыхательный, респираторный
restore, v.
/rɪˈstɔːr/
возвращать,
восстанавливать,
syn. rebuild, rebuild, rehab
substrate, n.
/ˈsʌbstreɪt/
подложка, основа
spontaneously,
/spɒnˈteɪniəslɪ/
непроизвольно, спонтанно
adv.
thermodynamics,
/ˌθɜːməʊdaɪˈnæmɪks/
термодинамика
n.
transfer, n.
/trænsˈfɜːr/
перенос, передача
transformation, n.
/trænsˈfɔːməɪʃən/
изменение,
преобразование,
превращение
unidirectional, adj. /ˈjuːnidaɪˈrekʃənəl/
однонаправленный
utilize, v.
/ˈjuːtɪlaɪz/
использовать, утилизировать
vital, adj.
/ˈvaɪtəl/
жизненно важный, насущный
READING
Read and translate the text using a dictionary if necessary:
Energy is the capacity to do work. All living organisms require energy
for carrying on their vital metabolic activities. The primary source of energy
for living system is solar radiation. The radiant energy of sunlight cannot be
utilised directly by all living organisms. This ability rests only with the
green plants. All the other organisms have to meet their energy requirement
only through the green plants. They represent the entry point for the flow of
energy in the living system, which is always unidirectional.
Energy that flows in the living system is called bio-energy and the
study of changes in energy as it
flows through a living system, is called
29
bioenergetics. It would be wise to mention that all energy conversions in the
living system are governed by certain invariable principles called laws of
thermodynamics, as in any physical system.
There are two types of energy
changes in the living system, namely
energy transformation and energy transfer. The examples of energy
transformation are following:
Photosynthesis - in which green plants transform radiant solar energy into
chemical energy that gets stored as potential energy in carbohydrates.
Bioluminescence -in which chemical energy is transformed into light
energy
Conduction of nerve impulses - in which chemical energy is transformed
into electrical energy
Muscular activity - in which chemical energy is transformed into
mechanical energy
A classic example of energy transfer in the living system is respiration.
Here, the chemical (potential) energy stored in respiratory substrates like
glucose, is transferred to ADP and is stored in ATP.
The ATP molecules
transfer energy to other biological molecules.
ATP (adenosine triphosphate) is an energy rich compound having three
phosphate group attached to a nucleoside of adenine (a nitrogen base),
called adenosine (adenine + pentose sugar). Of the three phosphate groups,
the terminal one has a weak linkage. This phosphate group can break
spontaneously whenever ATP forms a complex with an enzyme. The
breaking up of this bond releases chemical energy causing an immediate
shift in the bond energy giving rise to adenosine diphosphate (ADP). ATP is
therefore commonly described as energy currency of the cell.
In the given article special attention should be paid at entropy (the
usual symbol is S). Entropy is a measure of
the degree of disorder or
randomness of a system. It corresponds to the amount of energy that is not
available for work in a system. Loss of energy in the form of heat results in
an increase in the entropy of a system.
In the biological system, an increasing degree of entropy results in the
death of a cell or an organism, unless energy is restored. Living organisms
restore their lost energy either directly from sunlight (as in green plants) or
from their food molecules (as in other organisms).
(Adopted from
www.tutorvista.com
)