2. Energy Flow
In all living cells there is a continual transformation of
energy from one type to another. Energy cannot be
created or destroyed – simply changed from one form to
another “Law of Conservation of Energy” or “First Law of
Thermodynamics”
Energy is present in many forms
Light
Heat
Chemical
Kinetic
3. All living cells use energy for movement, synthesis
and maintenance of a stable intracellular
environment.
Movement
sperm
movement of chromosomes
Cell movement due to contraction of cytoskeleton
Synthesis
Conversion of one type of chemical energy to
another. Cells constantly require energy to break
down (catabolic) or build up (anabolic) molecules
4. Stable Environment
Cells need to maintain a constant internal environment –
homeostasis
Blood- glucose
Water
Core body temperature
O2 & CO2
Salt and ion
5.
6. Photosynthesis
Light energy is trapped by the green pigment chlorophyll
(mesophyll cells) which is found in organelles called chloroplasts
and converts light energy into chemical energy - glucose, starch
and oxygen.
8. Lower surface of a leaf consists of a layer called the
epidermis. The epidermis contains pairs of guard cells
enclosing tiny pores called stomate’s.
They become turgid as the guard cells swell or flaccid as
the guard cell loses water
9. These stomatal pores regulate water loss from a
plant as well as gas diffusion into and out of cell
10. Cellular respiration
Metabolism is the term used to name all
chemical reactions that occur in an organism.
Only 40% of energy created is used by the body,
the rest is lost as heat.
As large molecules are broken down into smaller
molecules some of the stored chemical energy is
converted to energy in chemical bonds of a small
molecule called ATP (most is released a heat)
11. ATP / ADP Conversion
Adenosine Tri – Phosphate is the cells immediate source
of energy.
ATP is composed of:
Adenine base
5 carbon (pentose) sugar
Three phosphate groups linked together
12. The bond between the last two phosphates is weak and
easily broken. When broken ATP becomes ADP (Adenosine
Di-Phosphate) resulting in free energy becoming available.
13. This energy becomes available for many of the bodies
metabolic reactions.
ATP stores are regenerated during cellular respiration
15. Aerobic Respiration
This is a complex metabolic process involving the
production of many intermediate products.
-Provides a controlled release of energy
-Many of these products are essential biological
molecules
Aerobic respiration involves a series of over 30 steps or
small reactions. It involves the removal of atoms from
large molecules or the transport of electrons across a
membrane
= oxidative phosphorylation
17. Metabolism
Anabolism – synthetic reactions in which small
molecules are used to build bigger molecules
Catabolism – large molecules are broken down to form
smaller molecules, releasing energy which is used to
form ATP.
The product of one reaction becomes the substrate or
the next – each involving a specific enzyme to catalyse
each compound.
19. Endothermic and Exothermic
reactions
Endothermic reactions (increase in metabolic rate)
is useful in warm- blooded animals in maintaining a
constant body temperature.
The opposite occurs in cold blooded animals which
depend on exothermic reactions to maintain
internal temperature.
