BIO1011
NOTES
,Contents
ATOMS, MOLECULES ......................................................................................................................... 3
4 CHARACTERISTICS OF LIVING ORGANISMS ...................................................................................... 6
ORGANIC MOLECULES ....................................................................................................................... 8
STRUCTURE OF PROTIENS................................................................................................................ 10
ENERGY ........................................................................................................................................... 11
ENZYMES......................................................................................................................................... 13
CELL MEMBRANE............................................................................................................................. 15
MICROBE ADAPTION ....................................................................................................................... 17
THE ENDOMEMBRANE SYSTEM ....................................................................................................... 19
PHOTOSYNTHESIS............................................................................................................................ 21
METABOLISM .................................................................................................................................. 24
BACTERIAL REPRODUCITON - BINARY FISSION ................................................................................. 27
CELL CYCLE ...................................................................................................................................... 29
GENETIC TERMS .............................................................................................................................. 33
TRANSCRIPTION .............................................................................................................................. 38
THE LAC OPERON ............................................................................................................................ 39
TRANSLATION.................................................................................................................................. 40
Heidy Weinberg equilibrium ............................................................................................................ 43
APOPTOSIS ...................................................................................................................................... 44
,ATOMS, MOLECULES
• Elements (pure substances that make up chemical compounds) are composed of atoms.
• Each element has one type of atom (protons, neutrons, electrons)
• Together, the protons and neutrons determine the atomic mass
• Isotopes are atoms of the same element that have different numbers of neutrons.
• Electrons occupy regions of space called orbitals
• Atoms can combine with other atoms to form molecules, which are groups of two or
more atoms attached together. that act as a single unit.
• When two atoms form a molecule, the individual atoms interact through what is called
a chemical bond
The ability of atoms to form bonds with other atoms explains in part why just a few types of
element can come together in many different ways to make a variety of molecules that can carry
out diverse functions in a cell. There are several ways in which atoms can interact with one
another, and therefore many different types of chemical bond.
• To become more stable atoms will share electrons to form molecules
• The number of bonds that can be made by an atom depends on the number of electrons
in the outer shell
COVALENT BONDS
• A covalent bond results when two atoms share electrons - two or more atoms share
electrons to fill outer shell
• valence electrons are at the highest energy level
polar covalent bond - when electrons are shared unequally between the two atoms,
nonpolar covalent bond – a covalent bond between atoms that have the same, or nearly the
same, electronegativity. Which means that the atoms share the bonding electron pair almost
equally.
electronegativity- The unequal sharing of electrons results from a difference in the ability of the
atoms to attract electrons
- increases across a row in the periodic table; as the number of protons across a row
increases, electrons are held more tightly to the nucleus.
IONIC BONDS
• An ionic bond forms between oppositely charged ions.
• Electrostatic bond between positive and negative ions
• Electrons lost(+)cations electrons gained(-)anion
• chemical reaction involves breaking and forming chemical bonds
, HYDROGEN BONDS
• A hydrogen bond is an interaction between a hydrogen atom and an electronegative
atom.
• Electrostatic attraction between hydrogen atom and electronegative atom
• Not a true “bond”, weaker
• Inter-between molecules Intra-within molecules
water
water molecules have polar covalent bonds, characterized by an uneven distribution of electrons.
A molecule like water that has regions of positive and negative charge is called a polar molecule
• polarity allows formation of hydrogen bonds
• electronegative charge is on the oxygen side
• electropositive charge is on the hydrogen side
properties water displays
• ability to create hydrophilic interactions
- hydrophilic compounds are polar; they dissolve readily in water. That is, water is
a good solvent, capable of dissolving many substances (sugar/salt and water
making a watery, aqueos environment)
• ability to create hydrophobic interactions
- hydrophobic compounds are nonpolar. Nonpolar compounds do not have
regions of positive and negative charge. As a result, they arrange themselves to
minimize their contact with water (oil and water)
• Highly cohesive – molecules of water tend to stick together
- This is due to the formation of those hydrogen bonds between the water
molecules
• Solid water (ice) is less dense than liquid water
- Due to the hydrogen bonds - single molecule can hydrogen bond with 4 other
molecules of water
- Crystalline structure
• High heat capacity
- Hydrogen bonds need extra energy for it to be broken down, move apart or
vibrate more frequently
• High heat evaporation
- It takes a lot of heat energy for water to evaporate or move away
NOTES
,Contents
ATOMS, MOLECULES ......................................................................................................................... 3
4 CHARACTERISTICS OF LIVING ORGANISMS ...................................................................................... 6
ORGANIC MOLECULES ....................................................................................................................... 8
STRUCTURE OF PROTIENS................................................................................................................ 10
ENERGY ........................................................................................................................................... 11
ENZYMES......................................................................................................................................... 13
CELL MEMBRANE............................................................................................................................. 15
MICROBE ADAPTION ....................................................................................................................... 17
THE ENDOMEMBRANE SYSTEM ....................................................................................................... 19
PHOTOSYNTHESIS............................................................................................................................ 21
METABOLISM .................................................................................................................................. 24
BACTERIAL REPRODUCITON - BINARY FISSION ................................................................................. 27
CELL CYCLE ...................................................................................................................................... 29
GENETIC TERMS .............................................................................................................................. 33
TRANSCRIPTION .............................................................................................................................. 38
THE LAC OPERON ............................................................................................................................ 39
TRANSLATION.................................................................................................................................. 40
Heidy Weinberg equilibrium ............................................................................................................ 43
APOPTOSIS ...................................................................................................................................... 44
,ATOMS, MOLECULES
• Elements (pure substances that make up chemical compounds) are composed of atoms.
• Each element has one type of atom (protons, neutrons, electrons)
• Together, the protons and neutrons determine the atomic mass
• Isotopes are atoms of the same element that have different numbers of neutrons.
• Electrons occupy regions of space called orbitals
• Atoms can combine with other atoms to form molecules, which are groups of two or
more atoms attached together. that act as a single unit.
• When two atoms form a molecule, the individual atoms interact through what is called
a chemical bond
The ability of atoms to form bonds with other atoms explains in part why just a few types of
element can come together in many different ways to make a variety of molecules that can carry
out diverse functions in a cell. There are several ways in which atoms can interact with one
another, and therefore many different types of chemical bond.
• To become more stable atoms will share electrons to form molecules
• The number of bonds that can be made by an atom depends on the number of electrons
in the outer shell
COVALENT BONDS
• A covalent bond results when two atoms share electrons - two or more atoms share
electrons to fill outer shell
• valence electrons are at the highest energy level
polar covalent bond - when electrons are shared unequally between the two atoms,
nonpolar covalent bond – a covalent bond between atoms that have the same, or nearly the
same, electronegativity. Which means that the atoms share the bonding electron pair almost
equally.
electronegativity- The unequal sharing of electrons results from a difference in the ability of the
atoms to attract electrons
- increases across a row in the periodic table; as the number of protons across a row
increases, electrons are held more tightly to the nucleus.
IONIC BONDS
• An ionic bond forms between oppositely charged ions.
• Electrostatic bond between positive and negative ions
• Electrons lost(+)cations electrons gained(-)anion
• chemical reaction involves breaking and forming chemical bonds
, HYDROGEN BONDS
• A hydrogen bond is an interaction between a hydrogen atom and an electronegative
atom.
• Electrostatic attraction between hydrogen atom and electronegative atom
• Not a true “bond”, weaker
• Inter-between molecules Intra-within molecules
water
water molecules have polar covalent bonds, characterized by an uneven distribution of electrons.
A molecule like water that has regions of positive and negative charge is called a polar molecule
• polarity allows formation of hydrogen bonds
• electronegative charge is on the oxygen side
• electropositive charge is on the hydrogen side
properties water displays
• ability to create hydrophilic interactions
- hydrophilic compounds are polar; they dissolve readily in water. That is, water is
a good solvent, capable of dissolving many substances (sugar/salt and water
making a watery, aqueos environment)
• ability to create hydrophobic interactions
- hydrophobic compounds are nonpolar. Nonpolar compounds do not have
regions of positive and negative charge. As a result, they arrange themselves to
minimize their contact with water (oil and water)
• Highly cohesive – molecules of water tend to stick together
- This is due to the formation of those hydrogen bonds between the water
molecules
• Solid water (ice) is less dense than liquid water
- Due to the hydrogen bonds - single molecule can hydrogen bond with 4 other
molecules of water
- Crystalline structure
• High heat capacity
- Hydrogen bonds need extra energy for it to be broken down, move apart or
vibrate more frequently
• High heat evaporation
- It takes a lot of heat energy for water to evaporate or move away
