AP Biology Unit 1 Flashcard Set

What is a polar molecule?

A molecule with an uneven distribution of electrical charge, giving it slightly positive and slightly negative regions.

Why is water polar?

Oxygen is more electronegative than hydrogen, so it pulls the shared electrons closer to itself, making oxygen slightly negative and hydrogens slightly positive.

What is electronegativity?

The tendency of an atom to attract shared electrons toward itself.

What type of bond exists between O and H within a water molecule?

A polar covalent bond.

What is a nonpolar molecule?

A molecule in which electrons are distributed relatively evenly, so it does not have significant partial positive and negative regions.

What is a hydrogen bond?

A weak attraction between a partially positive hydrogen and a partially negative electronegative atom.

Why is water a good solvent?

Because water is polar and can surround and separate charged particles and interact with other polar molecules.

What does hydrophilic mean?

Water

What does hydrophobic mean?

Water

What are the four major biological macromolecules?

Carbohydrates, lipids, proteins, and nucleic acids.

What is the primary role of carbohydrates?

Providing readily available energy, storing energy, and providing structural support.

What is the primary role of lipids?

They provide long term energy storage and forming plasma membrane storage.

What are proteins used for?

Enzymes, transport, structure, movement, signaling, defense, and many other cellular functions.

What are nucleic acids used for?

Storing and transmitting genetic information and helping direct protein production.

What is the monomer of a carbohydrate?

A monosaccharide.

What is the basic building block of a protein?

An amino acid.

What is the monomer of a nucleic acid?

A nucleotide.

Are lipids considered true polymers?

No. Unlike carbohydrates, proteins, and nucleic acids, lipids aren't generally made from repeating monomer units.

What is a functional group?

A specific group of atoms attached to an organic molecule that gives the molecule particular chemical properties.

What is the hydroxyl group?

What effect does a hydroxyl group generally have on a molecule?

It increases polarity and allows the molecule to form hydrogen bonds with water.

What is the carbonyl group?

A carbon atom double

What is the carboxyl group?

What does a carboxyl group generally do?

It can donate H+, making the molecule acidic.

What is the amino group?

What does an amino group generally do?

It can accept H+, giving the molecule basic properties.

What is the phosphate group?

A phosphorus atom bonded to oxygen atoms, commonly written as

Why are phosphate groups important biologically?

They carry negative charge and are important in molecules involved in energy transfer and genetic material.

What is the sulfhydryl group?

Why is the sulfhydryl group important in proteins?

Two sulfhydryl groups can form a disulfide bond, which can help stabilize protein structure.

What is the methyl group?

What is glucose?

A simple sugar with the chemical formula C₆H₁₂O₆ that serves as the primary source of energy for your body's cells

What is starch?

A polysaccharide made of many glucose molecules that plants use primarily for energy storage.

How are glucose and starch related?

Glucose is a single monosaccharide; starch is a polymer made from many glucose molecules.

What is alpha glucose?

An isomer of glucose where the -OH points down

What is beta glucose?

This is an isomer where the -OH is facing up.

Why does alpha vs. beta glucose matter?

The different orientations cause glucose molecules to form different types of linkages, producing polymers with different structures and functions.

What is cellulose?

A structural polysaccharide made from beta glucose

What is chitin?

A structural polysaccharide found in the cell walls of fungi and the exoskeletons of arthropods such as insects and crustaceans.

Why is chitin considered a structural carbohydrate?

It forms strong structures that provide support and protection.

What are the major types of lipids you should know?

Triglycerides, phospholipids, and steroids.

What is a triglyceride?

A lipid consisting of one glycerol molecule attached to three fatty acids.

What is glycerol?

A 3-carbon alcohol molecule with three hydroxyl (-OH) groups that acts as the backbone for triglycerides and phospholipids.

What is a fatty acid?

A molecule consisting of a hydrocarbon chain with a carboxyl group at one end.

What is a saturated fatty acid?

A fatty acid containing no carbon

What is an unsaturated fatty acid?

A fatty acid containing one or more carbon

What is the structural difference between saturated and unsaturated fatty acids?

Saturated fatty acids have only single bonds between carbon atoms; unsaturated fatty acids have at least one C=C double bond.

What is a phospholipid?

This is an amphipathic fluid.

What does amphipathic mean?

Having both a hydrophilic region and a hydrophobic region.

Why are phospholipids amphipathic?

Their phosphate

What are steroids?

Lipids characterized by four interconnected carbon rings.

What is one important biological role of phospholipids?

They are major components of cell membranes.

What is an amino acid?

The basic building block of proteins.

What are the three major components attached to the central carbon of an amino acid?

An amino group, a carboxyl group, and a variable R group; the central carbon also has a hydrogen attached.

What is an R group?

The variable portion of an amino acid that differs among amino acids and determines many of their chemical properties.

What bond connects amino acids?

A peptide bond.

What is a polypeptide?

A chain of amino acids connected by peptide bonds.

What is primary protein structure?

The specific sequence of amino acids in a polypeptide.

What is secondary protein structure?

Local folding of a polypeptide into structures such as alpha

What is tertiary protein structure?

The overall three

What is quaternary protein structure?

The arrangement of multiple polypeptide chains into one functional protein.

What types of interactions can help determine protein structure?

Hydrogen bonds, ionic interactions, hydrophobic interactions, and disulfide bonds.

What is a disulfide bond?

A covalent bond formed between the sulfur atoms of two cysteine side chains.

What is denaturation?

A change in a protein's three

What can cause protein denaturation?

Factors such as extreme temperature, extreme pH, or changes in the chemical environment.

Why is protein shape important?

A protein's shape determines how it interacts with other molecules, which is essential to its function.

What are nucleic acids?

Macromolecules that include DNA and RNA and are involved in storing, transmitting, and using genetic information.

What is a nucleotide?

The basic building block of nucleic acids.

What are the three parts of a nucleotide?

Phosphate Group, Sugar (Deoxyribose or Ribose), and Nitrogenous bases

What are the four nitrogenous bases in DNA?

Adenine, thymine, cytosine, and guanine.

What are the four nitrogenous bases in RNA?

Adenine, uracil, cytosine, and guanine.

What is the major structural difference between DNA and RNA?

DNA contains deoxyribose and thymine and is generally double

What is the primary role of DNA?

Long term transmission of genetic information

What are some major roles of RNA?

RNA participates in gene expression, including carrying and helping interpret genetic information for protein synthesis.

What are purines?

Adenine and guanine. They have two double-carbon interconnected ring structure.

What are pyrimidines?

Cytosine, thymine, and uracil. They have one ring.

What is a phosphodiester bond?

A covalent bond that connects nucleotides together in a nucleic acid strand.

What type of interaction holds complementary DNA bases together?

Hydrogen bonds.