AP BIO CLEP Unit I

What are elements?

Pure substances that cannot be broken down into simpler substances by chemical means.

What four elements make up approximately 96% of the mass of all living organisms?

Oxygen (O), Carbon (C), Hydrogen (H), and Nitrogen (N).

What are trace elements and give examples?

Elements required in minute amounts for biological functions, such as Iron (Fe), Iodine (I), and Copper (Cu).

What are the three subatomic particles of an atom?

Protons (positively charged), neutrons (neutral), and electrons (negatively charged).

What is an isotope?

Variants of elements that differ in neutron number, affecting their mass and stability.

What is the atomic number?

The number of protons in an atom.

What is a compound?

A substance formed when two or more elements combine in fixed ratios, resulting in new properties.

What type of bond occurs between metals and nonmetals?

Ionic bonds, involving the transfer of electrons.

What is a covalent bond?

A bond formed between nonmetals through the sharing of electrons.

What unique properties does water have due to its polarity?

Cohesion and adhesion, which are vital for processes like transpiration and capillary action.

What is the pH scale range for acids and bases?

Acids: 1-7, Bases: 7-14.

What are buffers?

Substances that help maintain stable pH levels in biological systems.

What are organic compounds?

Compounds that contain carbon.

What are hydrocarbons?

Organic molecules consisting solely of carbon and hydrogen.

What is the formula for glucose?

C6H12O6.

What are monosaccharides?

The simplest form of carbohydrates, including glucose and fructose.

What is a disaccharide?

A carbohydrate formed by the combination of two monosaccharides through dehydration synthesis.

What are polysaccharides?

Long chains of monosaccharides, such as starch, cellulose, chitin, and glycogen.

What are proteins made of?

Polymers made of amino acids.

What are the four levels of protein structure?

Primary, secondary, tertiary, and quaternary.

What is the role of chaperone proteins?

To assist in proper protein folding and prevent misfolding.

What are lipids?

Hydrophobic molecules composed mainly of carbon and hydrogen.

What is a triglyceride?

A type of lipid consisting of a glycerol molecule bonded to three fatty acid chains.

What distinguishes saturated fatty acids from unsaturated fatty acids?

Saturated fatty acids have no double bonds, while unsaturated fatty acids have one or more double bonds.

What is hydrolysis?

The process of breaking down disaccharides into monosaccharides.

What is dehydration synthesis?

The process of combining two monosaccharides to form a disaccharide.

What is the significance of water's high heat capacity?

It stabilizes temperatures in organisms and environments, crucial for maintaining homeostasis.

Why does ice float on water?

Because water expands upon freezing, creating a lattice structure that provides insulation for aquatic life.

What are polyunsaturated fatty acids characterized by?

They contain multiple double bonds, creating bends in the structure.

What is the role of phospholipids in cell membranes?

They have hydrophilic heads and hydrophobic tails, forming bilayers in aqueous environments.

How do steroids like cholesterol affect cell membranes?

They maintain membrane fluidity and stability, adapting to temperature changes.

What are the primary functions of lipids?

Energy storage, insulation, and forming cellular structures.

What are nucleic acids made of?

Polymers made of nucleotide monomers, which consist of a nitrogenous base, a pentose sugar, and a phosphate group.

What is the structure of DNA?

A double helix formed by two antiparallel strands of nucleotides with complementary base pairing (A-T and G-C).

What is the primary function of RNA?

To translate genetic information from DNA into proteins.

What is the significance of the RNA world hypothesis?

It suggests that early life forms were simple RNA molecules capable of replication and gene transmission.

What are the four main stages in the current theory of life's origins?

Formation of amino acids, polymerization of monomers, enclosure of organic molecules, and development of self-replicating systems.

What energy sources facilitated early organic synthesis on Earth?

Lightning and volcanic eruptions.

What distinguishes prokaryotic cells from eukaryotic cells?

Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have both.

What is the function of the plasma membrane?

It regulates movement in and out of the cell and is semipermeable.

What is the role of ribosomes in a cell?

They are the sites of protein synthesis.

What are the two forms of the endoplasmic reticulum?

Rough ER (with ribosomes) and smooth ER (without ribosomes).

What is the primary function of mitochondria?

To convert energy from organic molecules into ATP, the energy currency of the cell.

What do lysosomes do?

They contain digestive enzymes that break down waste materials and cellular debris.

What is the function of peroxisomes?

To break down fatty acids and detoxify harmful substances.

What is the smallest unit of living material capable of performing all necessary life activities?

The cell.

What is the significance of cell specialization?

It maintains a high surface area-to-volume ratio, facilitating efficient cellular exchanges.

What are the structural differences between prokaryotic, plant, and animal cells?

Prokaryotes lack a nucleus and organelles, plant cells have a cell wall, and animal cells have centrioles.

What is the role of the Golgi bodies?

To modify, process, and sort proteins synthesized in the rough ER.

What is the function of the nucleolus?

To synthesize rRNA and assemble ribosomes.

What is the fluid-mosaic model?

A description of the dynamic nature of the plasma membrane, with proteins and carbohydrates embedded within the lipid bilayer.

What is the significance of the sequence of nitrogenous bases in nucleic acids?

It encodes genetic information, with genes dictating the amino acid sequence of proteins.

What is the primary role of autotrophs in ecosystems?

To synthesize their own food, primarily through photosynthesis.

What are heterotrophs?

Organisms that rely on organic molecules for food.