AP Biology Unit 1: Chemistry of Life - Water, Macromolecules, and Cell Structures

What is the significance of the structure of monomers and polymers?

The structure determines their function.

What are the properties of water that result from its polarity and hydrogen bonding?

They affect its biological functions, such as being a solvent for polar and charged substances.

What type of bond is formed when atoms share electrons?

Covalent bonds.

What is an ionic bond?

A bond formed by the attraction of positive and negative ions, which dissociates easily in water.

How can you identify polar covalent bonds?

They occur between atoms with differing electronegativities, such as O & N compared to C & H.

What is the difference between cohesion and adhesion?

Cohesion is the attraction between water molecules, while adhesion is the attraction between water and other substances.

What is the role of water in transpiration?

Water's cohesion and adhesion allow plants to transport water without energy.

What is high specific heat capacity?

Water resists temperature change, acting as a good temperature buffer.

What is evaporative cooling?

The process where evaporating water molecules absorb a lot of energy, cooling the surface.

What does pH measure?

The concentration of hydrogen ions (H+) in a solution.

What does a low pH indicate?

A high concentration of H+, meaning the solution is acidic.

What are the three most common elements in living organisms?

Carbon, hydrogen, and oxygen.

What is dehydration synthesis?

A process where two molecules are combined with a covalent bond by removing water.

What is hydrolysis?

A process that cleaves covalent bonds between monomers by adding water.

What is the ratio of carbon, hydrogen, and oxygen in carbohydrates?

1:2:1 ratio (hydrated carbon).

What are monosaccharides?

Simple sugars that serve as the monomers for polysaccharides.

What is the function of simple sugars?

They provide quick energy.

What are complex carbohydrates used for?

They may store energy (e.g., starch) or provide structure (e.g., cellulose).

What are functional groups?

Groups of atoms that determine the properties of molecules.

What is polymerization?

The process of connecting many monomers to form polymers.

What is the role of buffers in living organisms?

They help to prevent pH changes in biological systems.

What happens to water molecules in a neutral solution?

The concentration of H+ is equal to OH-.

What is the primary function of simple sugars?

Simple sugars are used for quick energy.

What are the two main functions of complex carbohydrates?

Complex carbohydrates may store energy (e.g., starch) or provide structure (e.g., cellulose).

What is the basic structure of lipids?

Lipids are primarily composed of carbon and hydrogen (CHO) and are mostly nonpolar and hydrophobic.

What are triglycerides composed of?

Triglycerides consist of three fatty acids.

What distinguishes saturated fatty acids from unsaturated fatty acids?

Saturated fatty acids contain only single bonds, while unsaturated fatty acids contain at least one double bond, causing kinks in the chain.

What is the role of phospholipids in cell membranes?

Phospholipids form the lipid bilayer of membranes, with nonpolar fatty acid tails facing the interior away from water.

What are the functions of fats, steroids, and cholesterol?

Fats store energy and provide insulation; steroids act as hormones; cholesterol maintains structural stability in cell membranes.

What are nucleic acids made of?

Nucleic acids are made of nucleotides, which consist of a five-carbon sugar, a phosphate group, and a nitrogenous base.

What are the nitrogenous bases found in DNA?

The nitrogenous bases in DNA are adenine, thymine, cytosine, and guanine.

How do purines and pyrimidines differ?

Purines (adenine and guanine) have a double-ring structure, while pyrimidines (cytosine, uracil, and thymine) have a single-ring structure.

What is the directionality of nucleic acids?

Nucleic acids have ends based on the 3' hydroxyl and 5' phosphate of the sugar, with nucleotides added only to the 3' end.

What is the structural difference between DNA and RNA?

DNA contains deoxyribose sugar and is double-stranded, while RNA contains ribose sugar and is single-stranded.

What is the primary structure of proteins?

The primary structure of proteins refers to the sequence of amino acids connected by peptide bonds.

What determines the structure and function of a protein?

The interactions of the R groups of amino acids determine the structure and function of a protein.

What are the four levels of protein structure?

The four levels are primary (amino acid sequence), secondary (hydrogen bonds forming structures like alpha-helices and beta-pleated sheets), tertiary (3D shape from R group interactions), and quaternary (interactions between multiple polypeptides).

What is the timeline of life on Earth?

Earth formed approximately 4.6 billion years ago; life is thought to have originated between 3.9 and 3.5 billion years ago.

What does the RNA world hypothesis suggest?

The RNA world hypothesis proposes that RNA could have been the earliest genetic material, capable of encoding information and acting as a catalyst.

What is the endosymbiotic theory?

The endosymbiotic theory suggests that mitochondria and chloroplasts evolved from free-living prokaryotic cells through endosymbiosis.

What evidence supports the endosymbiotic theory?

Evidence includes that mitochondria and chloroplasts contain their own DNA, ribosomes, have a double membrane, and are similar in size to bacteria.