Ch 2 Study Guide
Vocabulary Words
Basic: the pH at which the intestinal enzyme trypsin works best
Cohesion: an attraction between substances of the same kind
Adhesion: an attraction between different substances
Acid: a compound that forms hydrogen ions when dissolved in water
RNA: subunits are made of sugar, a base, and a phosphate group
Carbohydrates: a class of organic compounds made of carbon, hydrogen, and oxygen atoms in a 1:2:1
ratio
Lipids: a class of organic compounds that includes fats, steroids, and waxes
ATP: provides temporary storage of energy for cells
Protein: a molecular chain of amino acids
pH: a measure of the concentration of hydrogen ions in solutions
Concepts to Consider
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The smallest unit of matter that cannot be broken down by chemical means is a(n) atom
The bonds between the atoms that make up water molecules are called covalent bonds
An atom is called an ion when it has either lost or gained electrons
A solution is a mixture of evenly distributed substances
Water is polar, therefore polar substances dissolve in it
Chemical reactions absorb, release, and require energy
Without energy, organisms could NOT maintain homeostasis, carry out chemical reactions, or
make their own food
All organic compounds contain carbon
Compounds are formed when atoms of two different elements join together
Enzymes reduce the activation energy of chemical reactions
The main energy currency of cells is APT
An enzyme acts only on specific substrates, which attach to the enzyme’s active site
A solution containing water and lime juice would be acidic
When ice melts, it absorbs heat from the environment
Salt dissolves in water because it is polar. Oil, a(n) nonpolar substance, does not dissolve in
water
In this chemical reaction, the type of chemical bonds being broken are ionic bonds
In the chemical reaction shown (NaCl = Na positive + Cl negative), sodium chloride is the
reactant, and sodium ions and chloride ions are the product
Enzymes that digest food in the stomach probably work best in a(n) acidic environment
When food molecules are broken down inside cells, some of the energy in the molecules is
stored temporarily in APT
Atoms bond with other atoms to form compounds because bonding helps atoms become more
stable
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An element is defined as a pure substance because it is made of only one kind of atom
Two solutions, A and B, are tested for pH. Solution A indicates a pH of 2. Solution B indicates a
pH of 7. You conclude that solution A is acidic and solution B is neutral
Glycogen and starch are carbohydrates in which energy is stored
Hydrogen bonds is what water molecules form with one another
The ability of water to form drops is an example of cohesion
Activation energy is needed by chemical reactions that release energy, absorb energy, and are
catalyzed by enzymes
In an atom with the same number of electrons and protons, the electrical charge is neutral