AP BIO UNIT 1 TEST STUDY
1. Atoms and Molecules
Atoms are the smallest units of matter, and they consist of:
Protons: Positively charged, located in the nucleus.
Neutrons: Neutral charge, located in the nucleus.
Electrons: Negatively charged, orbiting the nucleus.
Molecules are formed when two or more atoms join together through chemical bonds.
2. Types of Bonds
Covalent Bonds: A pair of electrons are shared between two atoms.
Can be single (one pair of electrons shared) or double (two pairs shared).
Polar Covalent Bonds: Molecules that do not share electrons equally, creating partial charges (- or +).
Nonpolar Covalent Bonds: Molecules that share electrons equally
Ionic Bonds: Electrons are transferred from one atom to another, creating full charges. (not partial charges like polar covalent bonds)
3. Isomers
Isomers are molecules with the same chemical formula but different structures, leading to different properties.
Example: Different arrangements of atoms or functional groups.
4. Organic vs. Inorganic Molecules
Organic Molecules: Contain carbon and are the building blocks of life.
Inorganic Molecules: Generally do not contain carbon.
1. Basics of Water
Water is a polar molecule, with partial negative charges near the oxygen atom and partial positive charges near the hydrogen atoms.
This polarity gives water its unique properties.
2. Hydrogen Bonds
Hydrogen Bonds: Weak bonds formed between the partial charges of water molecules.
3. Cohesion and Adhesion
Cohesion: Water molecules sticking to each other due to hydrogen bonding.
Adhesion: Water molecules sticking to other materials, helping plants in transpiration.
4. Moderation of Temperature
High Specific Heat: Water absorbs and releases heat slowly, stabilizing temperatures in environments and organisms.
Evaporative Cooling: When water evaporates, it cools the surface, stabilizing temperatures in bodies of water and in organisms (e.g., sweating in humans).
5. Expansion Upon Freezing
Water expands when it freezes, forming a less dense solid (ice) that floats, insulating liquid water beneath and allowing life to survive under frozen surfaces.
6. Water as a Solvent
Universal Solvent: Water can dissolve many substances due to its polarity, making it vital for life.
Solution: A homogeneous mixture of two or more substances.
pH Scale: Water is neutral with a pH of 7; acids have a pH below 7, and bases have a pH above 7.
Dehydration Synthesis: Water is removed to form a new compound, making a product plus a molecule of water.
Hydrolysis: Water is added to break down a compound, meaning the water is a reactant and is added to the product.
1. Protein Structure and Function
Monomer/Subunit: Amino acids are the building blocks of proteins.
General Structure of Amino Acids:
Consists of an amino group (-NH2), a carboxyl group (-COOH), and a variable R group that differentiates amino acids.
Function:
Proteins play various roles in the body, such as making structures, working in the immune system, and supporting the cardiovascular system.
Important Note: Proteins do not provide energy.
2. Primary Structure
Primary Structure: The sequence of amino acids in a protein, linked together by peptide bonds.
Impact of Sequence: Changing the primary structure (amino acid sequence) alters the protein's function.
3. Protein Functions (with Examples)
Enzymes: Speed up chemical reactions (e.g., lactase).
Defense: Protects the body (e.g., antibodies).
Storage: Stores nutrients (e.g., casein in milk).
Transport: Carries molecules (e.g., hemoglobin for oxygen).
Hormones: Regulate bodily functions (e.g., insulin).
Receptors: Receive signals from the environment.
Movement: Enable movement (e.g., motor proteins).
Structure: Provide support (e.g., keratin).
4. Four Levels of Protein Structure
Primary Structure:
The specific sequence of amino acids in a polypeptide chain.
There are 20 different amino acids.
Peptide bonds link the amino acids.
Secondary Structure:
Formed by interactions between sections of the primary structure.
Alpha Helix: Helical shape.
Beta Sheet: Flat, sheet-like structure.
Proteins often contain a mix of both alpha helices and beta sheets.
Tertiary Structure:
The overall 3D shape formed by bonding between R groups of amino acids.
Bonds involved include hydrogen bonds, ionic bonds, disulfide bridges, hydrophobic interactions, and van der Waals interactions.
Quaternary Structure:
Formed when two or more polypeptides bond together to function as a single protein.
5. Protein Structure and Environmental Sensitivity
Denaturation: Proteins can lose their shape (and function) if exposed to non-optimal pH or temperature.
Importance of Structure: A change in protein structure leads to a change in its function.
X-ray Crystallography: A technique used to determine the 3D structure of proteins.
1. Function
Store Hereditary Information: Nucleic acids store and transmit genetic information.
2. DNA vs. RNA
DNA (Deoxyribonucleic Acid):
Structure: Double-stranded helix.
Nitrogen Bases: Adenine (A), Guanine (G), Cytosine (C), Thymine (T).
Function: Stores hereditary information.
Size: Longer and larger than RNA.
Sugar: Deoxyribose.
RNA (Ribonucleic Acid):
Structure: Single-stranded.
Nitrogen Bases: Adenine (A), Guanine (G), Cytosine (C), Uracil (U).
Function: Carries information from DNA to ribosomes.
Types: Includes mRNA, tRNA, rRNA, and RNAi.
Sugar: Ribose.
3. Nucleotides
Monomer of DNA/RNA: Nucleotides.
Structure of a Nucleotide: Each nucleotide consists of a sugar (either ribose or deoxyribose), a phosphate group, and a nitrogenous base.
Organic Chemistry: Focuses on carbon compounds.
Organic Compounds: Contain Carbon and Hydrogen.
Major Elements of Life: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur (CHNOPS).
Carbon Properties:
Forms large, complex molecules.
Can form single, double, or triple covalent bonds.
Can be chains, ring-shaped, or branched.
Forms isomers (same molecular formula, different structures).
Hydroxyl (-OH): Polar, found in carbohydrates, proteins, and nucleic acids.
Carbonyl (-C=O): Polar, found in carbohydrates, and proteins.
Carboxyl (-COOH): Polar, negatively charged, found in fatty acids, and amino acids.
Phosphate (-OPO₃H₂): Polar, negatively charged, found in phospholipids, and nucleic acids.
Amino (-NH₂): Polar, positively charged, found in amino acids, and proteins.
Sulfhydryl (-SH): Polar, forms stable S-S bonds, found in proteins.
Amide (-C(=O)NH): Polar, found in proteins.
Methyl (-CH₃): Nonpolar, found in amino acids, proteins, and nucleic acids.
Function: Serve as fuel and building material.
Structure: Composed of simple sugars (monosaccharides) and polymers (polysaccharides).
Monosaccharides: Simple sugars (e.g., glucose, ribose).
Disaccharides: Formed from two monosaccharides.
Polysaccharides:
Storage: Starch (plants) and glycogen (animals).
Structure: Cellulose (plants) and chitin (arthropods).
Glucose Forms:
Starch: α-glucose monomers (digestible by humans).
Cellulose: β-glucose monomers (indigestible by humans, structural component).
Types:
Fats (Triglycerides):
Composed of glycerol + 3 fatty acids.
Saturated Fats: No double bonds, solid at room temperature.
Unsaturated Fats: At least one double bond, liquid at room temperature.
Steroids: Cholesterol and hormones, help regulate cell membrane fluidity.
Phospholipids: Key component of cell membranes, form bilayers due to hydrophobic and hydrophilic interactions.
Functions:
Energy Storage: Long-term energy, cushions organs.
Structural: Essential in the formation of cell membranes.
1. Atoms and Molecules
Atoms are the smallest units of matter, and they consist of:
Protons: Positively charged, located in the nucleus.
Neutrons: Neutral charge, located in the nucleus.
Electrons: Negatively charged, orbiting the nucleus.
Molecules are formed when two or more atoms join together through chemical bonds.
2. Types of Bonds
Covalent Bonds: A pair of electrons are shared between two atoms.
Can be single (one pair of electrons shared) or double (two pairs shared).
Polar Covalent Bonds: Molecules that do not share electrons equally, creating partial charges (- or +).
Nonpolar Covalent Bonds: Molecules that share electrons equally
Ionic Bonds: Electrons are transferred from one atom to another, creating full charges. (not partial charges like polar covalent bonds)
3. Isomers
Isomers are molecules with the same chemical formula but different structures, leading to different properties.
Example: Different arrangements of atoms or functional groups.
4. Organic vs. Inorganic Molecules
Organic Molecules: Contain carbon and are the building blocks of life.
Inorganic Molecules: Generally do not contain carbon.
1. Basics of Water
Water is a polar molecule, with partial negative charges near the oxygen atom and partial positive charges near the hydrogen atoms.
This polarity gives water its unique properties.
2. Hydrogen Bonds
Hydrogen Bonds: Weak bonds formed between the partial charges of water molecules.
3. Cohesion and Adhesion
Cohesion: Water molecules sticking to each other due to hydrogen bonding.
Adhesion: Water molecules sticking to other materials, helping plants in transpiration.
4. Moderation of Temperature
High Specific Heat: Water absorbs and releases heat slowly, stabilizing temperatures in environments and organisms.
Evaporative Cooling: When water evaporates, it cools the surface, stabilizing temperatures in bodies of water and in organisms (e.g., sweating in humans).
5. Expansion Upon Freezing
Water expands when it freezes, forming a less dense solid (ice) that floats, insulating liquid water beneath and allowing life to survive under frozen surfaces.
6. Water as a Solvent
Universal Solvent: Water can dissolve many substances due to its polarity, making it vital for life.
Solution: A homogeneous mixture of two or more substances.
pH Scale: Water is neutral with a pH of 7; acids have a pH below 7, and bases have a pH above 7.
Dehydration Synthesis: Water is removed to form a new compound, making a product plus a molecule of water.
Hydrolysis: Water is added to break down a compound, meaning the water is a reactant and is added to the product.
1. Protein Structure and Function
Monomer/Subunit: Amino acids are the building blocks of proteins.
General Structure of Amino Acids:
Consists of an amino group (-NH2), a carboxyl group (-COOH), and a variable R group that differentiates amino acids.
Function:
Proteins play various roles in the body, such as making structures, working in the immune system, and supporting the cardiovascular system.
Important Note: Proteins do not provide energy.
2. Primary Structure
Primary Structure: The sequence of amino acids in a protein, linked together by peptide bonds.
Impact of Sequence: Changing the primary structure (amino acid sequence) alters the protein's function.
3. Protein Functions (with Examples)
Enzymes: Speed up chemical reactions (e.g., lactase).
Defense: Protects the body (e.g., antibodies).
Storage: Stores nutrients (e.g., casein in milk).
Transport: Carries molecules (e.g., hemoglobin for oxygen).
Hormones: Regulate bodily functions (e.g., insulin).
Receptors: Receive signals from the environment.
Movement: Enable movement (e.g., motor proteins).
Structure: Provide support (e.g., keratin).
4. Four Levels of Protein Structure
Primary Structure:
The specific sequence of amino acids in a polypeptide chain.
There are 20 different amino acids.
Peptide bonds link the amino acids.
Secondary Structure:
Formed by interactions between sections of the primary structure.
Alpha Helix: Helical shape.
Beta Sheet: Flat, sheet-like structure.
Proteins often contain a mix of both alpha helices and beta sheets.
Tertiary Structure:
The overall 3D shape formed by bonding between R groups of amino acids.
Bonds involved include hydrogen bonds, ionic bonds, disulfide bridges, hydrophobic interactions, and van der Waals interactions.
Quaternary Structure:
Formed when two or more polypeptides bond together to function as a single protein.
5. Protein Structure and Environmental Sensitivity
Denaturation: Proteins can lose their shape (and function) if exposed to non-optimal pH or temperature.
Importance of Structure: A change in protein structure leads to a change in its function.
X-ray Crystallography: A technique used to determine the 3D structure of proteins.
1. Function
Store Hereditary Information: Nucleic acids store and transmit genetic information.
2. DNA vs. RNA
DNA (Deoxyribonucleic Acid):
Structure: Double-stranded helix.
Nitrogen Bases: Adenine (A), Guanine (G), Cytosine (C), Thymine (T).
Function: Stores hereditary information.
Size: Longer and larger than RNA.
Sugar: Deoxyribose.
RNA (Ribonucleic Acid):
Structure: Single-stranded.
Nitrogen Bases: Adenine (A), Guanine (G), Cytosine (C), Uracil (U).
Function: Carries information from DNA to ribosomes.
Types: Includes mRNA, tRNA, rRNA, and RNAi.
Sugar: Ribose.
3. Nucleotides
Monomer of DNA/RNA: Nucleotides.
Structure of a Nucleotide: Each nucleotide consists of a sugar (either ribose or deoxyribose), a phosphate group, and a nitrogenous base.
Organic Chemistry: Focuses on carbon compounds.
Organic Compounds: Contain Carbon and Hydrogen.
Major Elements of Life: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur (CHNOPS).
Carbon Properties:
Forms large, complex molecules.
Can form single, double, or triple covalent bonds.
Can be chains, ring-shaped, or branched.
Forms isomers (same molecular formula, different structures).
Hydroxyl (-OH): Polar, found in carbohydrates, proteins, and nucleic acids.
Carbonyl (-C=O): Polar, found in carbohydrates, and proteins.
Carboxyl (-COOH): Polar, negatively charged, found in fatty acids, and amino acids.
Phosphate (-OPO₃H₂): Polar, negatively charged, found in phospholipids, and nucleic acids.
Amino (-NH₂): Polar, positively charged, found in amino acids, and proteins.
Sulfhydryl (-SH): Polar, forms stable S-S bonds, found in proteins.
Amide (-C(=O)NH): Polar, found in proteins.
Methyl (-CH₃): Nonpolar, found in amino acids, proteins, and nucleic acids.
Function: Serve as fuel and building material.
Structure: Composed of simple sugars (monosaccharides) and polymers (polysaccharides).
Monosaccharides: Simple sugars (e.g., glucose, ribose).
Disaccharides: Formed from two monosaccharides.
Polysaccharides:
Storage: Starch (plants) and glycogen (animals).
Structure: Cellulose (plants) and chitin (arthropods).
Glucose Forms:
Starch: α-glucose monomers (digestible by humans).
Cellulose: β-glucose monomers (indigestible by humans, structural component).
Types:
Fats (Triglycerides):
Composed of glycerol + 3 fatty acids.
Saturated Fats: No double bonds, solid at room temperature.
Unsaturated Fats: At least one double bond, liquid at room temperature.
Steroids: Cholesterol and hormones, help regulate cell membrane fluidity.
Phospholipids: Key component of cell membranes, form bilayers due to hydrophobic and hydrophilic interactions.
Functions:
Energy Storage: Long-term energy, cushions organs.
Structural: Essential in the formation of cell membranes.
