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1. Molecules
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1. Molecules
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1. Molecules
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Understanding Points
Structure of water
•
Polar covalent bonds:
unequal sharing
of e⁻ → partially negative O atom, partially positive H atoms
•
Hydrogen bonding:
intermolecular force
between the O and H of different H₂O molecules
A1.1.1 Water Structure
Properties of water
A1.1 Water
Understanding points
Structure of DNA
•
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are the genetic material of all species
•
Nucleotide
= phosphate group + pentose + nitrogenous base
•
Sugar-phosphate backbone
: synthesized in 5’ → 3’ direction
A1.2.1 Structure of DNA
A1.2 Nucleic acids
Understanding points
Carbon as the basis of life
•
Forms strong
covalent bonds
with other atoms to form stable molecules
•
Can form up to 4 covalent bonds and give rise to molecules with complex structures
Condensation and hydrolysis
•
Condensation:
bonds monomers together into a polymer by
removal
of water
•
Hydrolysis:
breaking a polymer apart into smaller ones by
addition
of water
Carbohydrates
B1.1 Carbohydrates and lipids
Understanding points
Amino acids
•
20 different types of naturally occurring 𝛼𝛼
•
*(AHL)
R groups can be hydrophobic, hydrophilic, or charged
B1.2.1 Amino acids
Denaturation
•
A structural change in a protein that results in the loss of its biological function
•
Heat and acid disrupt the intermolecular bonds in proteins
B1.2 Proteins
Understanding points
Enzymes
•
Biological
catalysts
that speed up the rate of reaction
•
Lower the
activation energy
(Eₐ) by providing alternative mechanism for the reaction
•
Active site
: the specific binding site of a substrate
C1.1.1 Enzyme
Anabolism vs Catabolism
Factors affecting enzyme activity
C1.1 Enzymes and metabolism
Understanding points
ATP
•
Adenosine triphosphate
•
Energy currency of the cell
•
Water soluble, chemically stable at neutral pH
•
Used for active transport, cell motility, macromolecule synthesis
•
Produced by cell respiration
C1.2.1 ATP
C1.2 Cell respiration
Understanding points
Photosynthesis
•
Conversion of light energy to chemical energy by algae, plants, cyanobacteria
•
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
•
Limiting factors: temperature, light intensity, CO₂ conc
C1.3.1 Factors affecting Photosynthesis
Chromatography
•
Separation of the components of a mixture
C1.3 Photosynthesis
Understanding points
DNA replication
•
Occurs during
S phase
in interphase
•
Produces identical diploid daughter cells in mitosis
•
Semiconservative:
each DNA molecule produced has one new strand and one parental strand
D1.1.1 DNA Replication
DNA replication enzymes
D1.1 DNA replication
Understanding points
Transcription
•
Production of mRNA from DNA by RNA polymerase
D1.2.1 Transcription
Translation
D1.2 Protein synthesis
Understanding points
Mutation
•
A random, permanent change in the base sequence of DNA
•
Generates
genetic variation
upon which natural selection can act
•
Mutagens:
agents that increase the frequency of mutations above the natural background level
D1.3.1 Mutation
Types of point mutation
D1.3 Mutations and gene editing
