EARTH AND LIFE SCIENCE CHAPTER 6 BIOENERGETICS

The plant, the caterpillar, and the bird are all living things.
Like any other living things, these organisms need energy in
order to live. You as living thing, also need energy to power up
everything you do. Whether you are running or sleeping, your
body uses energy. In fact, every cell in your body needs
energy to carry out its processes. Where do organisms get
energy? How do different organisms utilize the energy coming
from the sun? p.104

ENERGY:
Is the ability to do work. It is necessary
in metabolism.

HOW DO ORGANISMS GET ENERY?
• Organisms usually get the chemical energy they
need from food. Food consist of organic
molecules that store energy in the form of
chemical energy.

• AUTOTROPHS
organisms that make their own food.
CYANOBACTERIAALGAETREE
• PRODUCERS
Make food not only for themselves
but for other living organisms as
well.

• HETEROTROPHS
 They may consume autotrophs, other heterotrophs,
or both.
 Includes animals, fungi, and some single-celled
organisms
Organisms that cannot make their own.
Food obtain by consuming other organisms.

HOW DO ORGANISMS GET ENERY?
Example of a food chain

WHAT ARE THE ENERGY-GIVING ENERGY?
2 TYPES OF ENERGY-GIVING MOLECULES:
1.) GLUCOSE
2.) ATP (Adenosine Triphosphate)
Cellular Respiration – the stored energy in glucose
is released in a reverse reaction of photosynthesis.
Adenosine Triphosphate (ATP) – molecules store smaller
amount of energy, but each molecule released enough
energy to do the work within the cell.

PHOTOSYNTHETIC ORGANELLES
2 GROUP OF PIGMENTS (PLANTS)
1.) CHLOROPYLLS
2.) CAROTENOIDS
• Chloropyll a and Chloropyll b – are green pigments that absorbs
all wavelengths of light in the red, blue, and violet ranges.
• Carotenoids – are yellow, orange and red pigments.
• Phycobilins – The pigment found in red algae
which give them their reddish color absorb light in
blue and green ranges.

CHLOROPLASTS
• are cell organelles found in
plants and algae.

1.) PHOTOSYSTEM I (PS I)
• Absorbs light best in 680 nm range; hence it is sometimes
called P680.
2.) PHOTOSYSTEM II (PS II)
• Absorbs light best in 700 nm range, hence it is also called
P700.
2 TYPES OF PHOTOSYSTEM:

PHOTOSYNTHESIS
• Is often regarded as the most important
life process on earth.

2 STAGES
1.) STAGE I includes light-dependent reactions
Directly use the light energy to produce ATP and NADPH.
2.) STAGE II includes the light-independent reactions
Also called CALVIN CYCLE, the ATP and NADPH from light
reactions are used to create glucose.
PHOTOSYNTHESIS

STAGE I: LIGHT DEPENDENT REACTIONS

1. Two electrons, which replace the electrons loss of
chloropyll a in PS II during the light absorption.
2. Two Hydrogen ions (2H’), which are positively charged
and are released inside the interior space of the thylakoid
membrane.
3. Oxygen (O) atom tat combines with another oxygen atom,
producing one oxygen molecule (02), which is released
into the atmosphere as a waste product.
Water splits apart and produces the following:

STAGE II: LIGHT-INDEPENDENT REACTIONS
The Second stage of photosynthesis happens in the
stroma surrounding the thylakoid in the chloroplast.
1. Carbon Fixation - occurs when carbon dioxide from the atmosphere
combines wit a simple five-carbon (5-c) sugar compound, ribulose
biphospate (RuBP), forming an unstable six-carbon (6-C) molecule.
2. Reduction reactions – The 3-PGA molecules gain energy from the
ATP and NADPH from the light reactions, and rearrange themselves
to from glycerate 3-phosphate (G3O),
3. 3. Regeneration of RuBP – The remaining G3P molecules then use
more ATP to convert back into RuBP, completing the cycle
3 MAJOR STEPS OF CALVIN CYCLE:

CELLULAR RESPIRATION
Is the means by which cells release the stored
energy in glucose to make ATP.

Figure 6-6. Overview
of cellular respiration
process.
p.111

STAGE I. GLYCOLYSIS
is the process that breaks down one molecule of
6-C glucose into 3-C pyruvates or pyruvic acids.
• In summary, a single glucose molecule that undergoes the
process of glycolysis produces two molecules of pyruvic acid,
four molecule of ATP, two molecules of NADPH, and two
molecules of H2O. However only two molecules of ATP are
counted as net products since two molecules of ATP are
spent thoughout the process

Figue 6-7. Summary of
glycolysis (Enzymes and
corresponding products in
each reaction are also
presented)
Page.112

STAGE II: KREBS CYCLE
Is a cyclical series of enzyme-controlled reactions. This
stage of cellular respiration occurs in the matrix of the
mitochondria of a cell.
Figue 6-8.
The Krebs cycle and
the preparatory
reaction preceding it
Page.113

STAGE III: ELECTRON TRANSPORT
The electron transport chain (ETC) is a series of photon
pumps on the inner membrane of the mitochondrion.
Electron transport is the last stage of cellular respiration.
Figure 6-10.
Events of the electron
transport chain.
Page.115

ANAEROBIC RESPIRATION
Most cells carry out aerobic respiration when oxygen
is present. Aerobic is an efficient process, which
yields a lot of ATP.
Cellular respiration that process without the presence
of oxygen is called anaerobic respiration.

ALCOHOLIC FERMENTATION
In alcoholic fermentation, ethyl alcohol and carbon dioxide are
produced by some cells using the pyruvate from glycolysis.
Figure 6-11. Alcoholic
fermentation : In this
pathway, acetaldehyde
serves as the final electron
acceptor and produces
ethanol.
p. 116

LACTIC ACID FERMENTATION
Pyruvate itself becomes the final acceptor of the electrons from
the NADH that produces the final product.
Figure 6-12. Lactic
acid fermentation: In
this pathway, electron
end up in the reaction
product, lactate.
Page. 117

EARTH AND LIFE SCIENCE CHAPTER 6 BIOENERGETICS

EARTH AND LIFE SCIENCE CHAPTER 6 BIOENERGETICS

More Related Content

What's hot

Similar to EARTH AND LIFE SCIENCE CHAPTER 6 BIOENERGETICS

More from JJennn JJJen

Recently uploaded

In this document

EARTH AND LIFE SCIENCE CHAPTER 6 BIOENERGETICS