Unit 1 Test - AP Bio Study

How is hydrogen bonding possible?

Hydrogen bonds form because water is polar: oxygen is slightly negative (δ−) and hydrogen is slightly positive (δ+). The H of one water molecule is attracted to the O of another.

What is cohesion?

Water sticking to water (same molecules).

What is adhesion?

Water sticking to other substances (different molecules).

What is an easy way to remember cohesion vs. adhesion?

COhesion = COmpanions/same. ADhesion = ADifferent/different.

How does cohesion create surface tension?

Cohesion pulls water molecules together at the surface, creating a tight "skin."

How do cohesion and adhesion help plants?

Cohesion keeps water molecules together, while adhesion helps water stick to xylem walls; together they help water move upward.

Why does ice float on water?

Hydrogen bonds create an open structure in ice, making ice less dense than liquid water.

Why does water have a high specific heat?

Hydrogen bonds absorb lots of energy before water's temperature changes significantly, helping organisms maintain stable temperatures.

Why is water's high specific heat important to organisms?

It helps organisms maintain homeostasis by preventing rapid temperature changes.

Why is carbon important?

Carbon can form 4 covalent bonds, allowing it to build many complex molecules.

What does CHONPS stand for?

Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur.

Where do organisms obtain their materials?

From their environment.

What does "structure determines function" mean?

The shape and structure of a molecule determine what it can do.

What are isomers?

Molecules with the same molecular formula but different arrangements of atoms.

What are structural isomers?

Isomers with the same molecular formula but different connections between atoms.

What are stereoisomers?

Molecules with the same molecular formula and same atom connections but different 3D arrangements.

What is a carbohydrate's monomer?

Monosaccharide.

What is the most common monosaccharide?

Glucose.

What are the main functions of carbohydrates?

Quick/short-term energy and some structural support.

What suffix is common in carbohydrates?

-ose.

What is a lipid made from?

Fatty acids and glycerol; lipids are not true polymers.

What are the main functions of lipids?

Long-term energy storage, cell membranes, insulation, and hormones/signaling.

What is the monomer of a protein?

Amino acid.

What are the main functions of proteins?

Enzymes, transport, movement, structure, defense, and signaling.

What is the monomer of nucleic acids?

Nucleotide.

What are examples of nucleic acids/nucleotides?

DNA, RNA, and ATP.

What are the main functions of nucleic acids?

Store/transmit genetic information; some nucleotides such as ATP are involved in energy transfer.

What happens when a polymer is broken down?

Monomers are released; hydrolysis uses water to break the bonds.

What is dehydration synthesis?

A process that builds larger molecules by removing H₂O.

What is hydrolysis?

A process that breaks larger molecules apart by adding H₂O.

What is the easiest way to remember dehydration synthesis?

Dehydration = remove water = BUILD.

What is the easiest way to remember hydrolysis?

Hydrolysis = add water = BREAK.

What type of bond connects monomers into polymers?

Covalent bonds.

What bond connects carbohydrates?

Glycosidic bonds.

What bond connects amino acids in proteins?

Peptide bonds.

What bond connects nucleotides in nucleic acids?

Phosphodiester bonds.

Do polymers have to be made of identical monomers?

No. Some polymers can contain different types of monomers.

What are phospholipids?

Lipids that make up cell membranes and have a hydrophilic head and hydrophobic tails.

What does amphipathic mean?

Having both hydrophilic and hydrophobic regions.

Which part of a phospholipid is hydrophilic?

The phosphate head.

Which part of a phospholipid is hydrophobic?

The fatty acid tails.

What is a saturated fatty acid?

A fatty acid with no C=C double bonds; it is usually solid at room temperature.

What is an unsaturated fatty acid?

A fatty acid with one or more C=C double bonds; it is usually liquid at room temperature.

How can you tell saturated and unsaturated fatty acids apart?

Saturated = no double bonds. Unsaturated = at least one double bond.

Why are unsaturated fats often liquid?

Double bonds create kinks that prevent fatty acid chains from packing tightly.

What are the similarities between DNA and RNA?

Both are nucleic acids made of nucleotides and have sugar-phosphate backbones.

What are the main differences between DNA and RNA?

DNA is usually double-stranded, has deoxyribose, and uses thymine (T). RNA is usually single-stranded, has ribose, and uses uracil (U).

What sugar is found in DNA?

Deoxyribose.

What sugar is found in RNA?

Ribose.

Which nitrogenous base is found in DNA but not RNA?

Thymine (T).

Which nitrogenous base is found in RNA instead of thymine?

Uracil (U).

What forms the backbone of DNA?

Sugar and phosphate.

What type of bond connects nucleotides within one DNA strand?

Phosphodiester bonds.

What type of bond holds the two DNA strands together?

Hydrogen bonds between complementary nitrogenous bases.

Which part of a nucleotide contains genetic information?

The nitrogenous base.

What determines the genetic information in DNA?

The sequence of nitrogenous bases.

What makes each amino acid different?

Its R group (side chain).

What is primary protein structure?

The specific sequence of amino acids.

What is secondary protein structure?

Local folding into structures such as alpha helices and beta-pleated sheets.

What mainly causes secondary protein structure?

Hydrogen bonding along the protein backbone.

What is tertiary protein structure?

The overall 3D shape of one polypeptide caused by interactions between R groups.

What is quaternary protein structure?

The arrangement of multiple polypeptide chains into one functional protein.

What is an easy way to remember the four protein structures?

Primary = sequence; Secondary = local folds; Tertiary = 3D shape; Quaternary = multiple chains.

What can happen if the primary structure of a protein changes?

It can change the protein's folding, potentially altering secondary/tertiary structure and function or the entire structure.

What is the relationship between protein sequence, shape, and function?

Sequence → Shape → Function.

What is the independent variable?

The variable that is deliberately changed; usually placed on the X-axis.

What is the dependent variable?

The variable that is measured; usually placed on the Y-axis.

What are control variables?

Factors kept the same so they do not affect the results.

What does X = in a graph?

X-axis = independent variable = what I change.

What does Y = in a graph?

Y-axis = dependent variable = what I measure.

What are the four major macromolecules?

Carbohydrates, lipids, proteins, and nucleic acids.

What are carbohydrates mainly used for?

Quick energy.

What are lipids mainly used for?

Long-term energy storage and cell membranes.

What are proteins mainly used for?

Doing cellular jobs such as enzymes, transport, structure, and signaling.

What are nucleic acids mainly used for?

Genetic information.

What is the key idea connecting structure and function?

A molecule's structure/shape determines its function.