General Biology
101-Bio NYA
Lecture goals
• Course outline
• Properties of life
• Energy flow
Properties of Life
What is life?
• Please list the properties that you think define
life.
Properties of life
1. Order
2. Reproduction
3. Growth & development
4. Energy utilization: organisms take in energy
(food) and transform the energy to do work
5. Homeostasis: regulation of the internal
environment
6. Evolutionary adaption: survival of the fittest
7. Response to the environment
Properties of life
Life comes in many forms
Levels of biological organization
The next few classes will focus on
• Energy
• Biomolecules
– Carbohydrates
– Lipids
– Proteins
– Nucleic acids (DNA and RNA)
• How molecules are changed into other
molecules and energy the cell can use.
Energy!
Life requires the transfer and
transformation of energy and matter
• A fundamental characteristic of living
organisms is the transformation of energy and
use of energy to carry out activities.
• The primary source of energy for life on Earth
is the Sun.
Organisms can be classified by how
they obtain energy
• Autotrophs (ex. Photosynthetic organisms)
– Producers Organicmolecules
Molecules w C C bond
• Do not consume other organisms
• Make their own organic molecules by
photosynthesis
• Plants, some bacteria and algae
Organisms can be classified by how
they obtain energy
• Heterotrophs (consumers)
• Cannot make their own food
• Must consume other organisms or molecules
made from other organisms
• Animals, some bacteria, some archaea and
some algae
Food Chain
Transfer
ofenergy
Food web
Terrestrial food web
Aquatic food web
Trophic structure of the food web
The energy pyramid
Only ~10% of the energy is
transferred to the next
trophic level.
Other90 lost in environment heat
Energy flow
The flow of energy
• Photosynthesis: transformation of solar E to
chemical E (glucose)
• Occurs in plants, algae and some bacteria
• In the chloroplast within the cell
• Organisms that perform photosynthesis are
producers
CO2 + H2O + solar E → C6H12O6 (glucose) + O2
The flow of energy
• Cellular respiration: breaks down organic molecules,
releases energy trapped in bonds and uses it to make
ATP.
• Releases chemical E in the form of ATP
• Chemical Energy → Chemical Energy
• Occurs in all organisms, including plants
• In the mitochondria within the cell
C6H12O6 (glucose) + O2 → CO2 + H2O + ATP
What is ATP you ask?
• ATP (adenosine triphosphate)
• Molecule
• Energy currency for the cell
• Stores E for:
– Cellular work (muscular contraction, chromosomal
movements during cell division)
– Transportation (pumping molecules across
membranes)
– Chemical reactions
All beings use ATP respiration incl plants
ATP consists of 3 components
1. A nitrogenous base called adenine
2. A 5-carbon sugar called ribose
3. Three phosphate groups which are If no atom
in one corner
negatively charged C is present
What’s so special about ATP?
• Breaking bonds in ATP releases energy
• The process is called hydrolysis because water
is involved in breaking the bonds
lysis breaking
Hydrolysis of ATP
ATP is a renewable resource in the cell
• When ATP is broken down E is released and this can be used
by the cell for a process that requires E
• When the cell carries out a reaction that releases E, this E can
be used to build ATP from its components
• When ATP breaks down, it releases a phosphate group, called
inorganic phosphate (Pi). The adenosine triphosphate (ATP)
has been converted to adenosine diphosphate (ADP)
What types of processes release
energy?
• Catabolism: The process involving a series of
degradative chemical reactions that break
down complex molecules into smaller units,
usually releasing E in the process.
• Catabolic processes are exergonic
Release energy
What types of processes require
energy?
• Anabolism: The process involving a sequence of
chemical reactions that construct or synthesize
molecules from smaller units, usually requiring an
input of E (ATP) in the process.
• Anabolic processes are endergonic
But… wait…
• If we need to break molecules to release
energy to be used to make ATP so that we can
break ATP to release energy to do cellular
work, why can’t we just the energy from the
first round of molecular breaking???
But… wait…
• If we need to break molecules to release
energy to be used to make ATP so that we can
break ATP to release energy to do cellular
work, why can’t we just the energy from the
first round of molecular breaking???
But… wait…
• If we need to break molecules to release
energy to be used to make ATP so that we can
break ATP to release energy to do cellular
work, why can’t we just the energy from the
first round of molecular breaking???
• In actuality, breaking the bond doesn’t just
release energy that is captured. More
complicated chemistry is at work that you will
learn about in Bio II.
