Chapter 2 The Chemistry of Life Study Guide

Describe the roles of a catalyst and a substrate in a chemical reaction.

A catalyst is a substance that speeds up the rate of a chemical reaction by lowering the activation energy. The substrate is the reactant in an enzyme-catalyzed reaction.

catalyst, enzyme, activation energy

A catalyst lowers the activation energy. An enzyme is an example of a catalyst.

How do a sodium atom and a positive sodium ion differ?

A sodium atom is a neutral particle that contains equal num- bers of protons and electrons. A positive sodium ion is a sodium atom that has a positive charge because it has lost an electron.

How do acids and bases differ?

Acids are compounds that have high- er concentrations of H+ ions than pure water and have pH values below 7. Bases are compounds that have lower concentrations of H+ ions than pure water and have pH values higher than 7.

Isotope

Atoms of the same element that differ in the number of neutrons they contain

Hydrogen Bonds

Because of their partial positive and negative charges, polar molecules such as water can attract each other.

Plastics are synthetic, organic polymers. How are plastics similar to polysaccharides? How are they different?

Both plastics and polysac- charides are organic polymers, or chains of carbon- containing molecules. Polysaccharides are naturally occurring molecules found in the body, while plastics are synthetic molecules made in factories or labs.

During a chemical reaction, chemical bonds are ______________.

Broken

Sugar and starches

Carbohydrates

The Main source of energy for living things

Carbohydrates

No other element can form the amount and variety of molecules that carbon can form. What characteristics does carbon have that explain this characteristic?

Carbon atoms have 4 valence electrons and therefore can form 4 strong, sta- ble, covalent bonds. Carbon can also bond with other carbon atoms, which gives it the ability to form chains and rings. These carbon-carbon bonds can be single, double, or triple bonds.

How do cohesion and adhesion differ?

Cohesion is an attraction between molecules of the same sub- stance, and adhesion is an attraction between dif- ferent substances.

Ribonucleic acid (RNA)

Consists of a single strand of nucleotides or of based paired nucleotides.Plays a key role in the manufactoring of proteinss.

Deoxyribnucleic acid (DNA)

Consists of two strands of nucleotides that spiral around each other. Chromosomes contain long strands of these which store heredity information.

The two main types of chemical bonds are ________ and _________

Ionic and Covalent

The main types of chemical bonds

Ionic bonds and covalent bonds

Polymers

Large compound formed from combinations of many monomers.

Glucose, galactose, and fructose are carbohydrates called

Monosaccharides

Contain Hydrogen, oxygen, nitrogen, phosphorous, and carbon.

Nucleic Acids

store and transmit hereditary information

Nucleic Acids

Composed of amino acids

Proteins

Help carry out chemical reactions

Proteins

Transport substances in and out of cells

Proteins

what are polymers of amino acids?

Proteins

Two kinds of nucleic acids

Ribonucleic acid ( RNA ) deoxyribonucleic acid ( DNA )

The two basic Kinds of nucleic acids are

Ribonucleic acid (RNA) and Deoxyribonucleic acid (DNA)

Monomers

Small unit that can join together with other small units to form polymers.

Products

The elements or compounds produces bye a chemical reaction.

Polysaccharides

The large macromolecules formed from monosaccharides are known as.....

Atom

The smallest unit of matter that cannot be broken down by chemical means.

Most enzymes in the human body work best at 37C. Imagine scientists have discovered an enzyme in the body that works best at 39C. What processes or functions might this enzyme be involved in?

This imaginary enzyme would work best when the body temperature is elevated. Therefore, students' answers should mention a function involving recovery from fever or reduction of body tempera- ture after exercise.

In a salt solution, why is water the solvent and salt the solute?

Water is the solvent because it is the substance that the salt is dissolved in, and salt is the solute because it is the substance that is dissolved.

van der Walls forces

When molecules are close together, a slight attraction can develop between the oppositely charged regions of nearby molecules. ( not as strong as ionic or covalent bonds )

Base

a compound that produces hydroxide ions (OH- ions) in solution. Basic, or alkaline, solutions contain higher concentrations of H+ ions than pure water and have pH values below 7. Strong bases, such as lye, tend to have pH values ranging from 11 to 14.

Lipids

a large varied group of biological molecules that are generally not soluble in water. Lipids are made mostly from carbon and hydrogen atoms.

Mixture

a material composed of two or more elements or compounds that are physically mixed together but not chemically combined.

pH scale

a measurement system used to indicate the concentration of H+ ions in solution. The pH scale ranges from 0 to 14.

Element

a pure substance that consists entirely of one type of atom.

Compound

a substance formed by the chemical combination of two or more elements in definite proportions.

Catalyst

a substance that speeds up the rate of a chemical reaction by lowering the reactions activation energy.

Biological catalysts, or enzymes, act by lowering the _________ required for a reaction.

activation energy

Solution

all the components are evenly distributed throughout to form this.

Cohesion

an attraction between molecules of the same substance.

Acids

any compound that forms H+ ions in a solution. acids contain higher concentrations of H+ ions than pure water and have a pH values below 7. Strong acids tend to have pH values that range from 1 to 3.

isotopes

atoms of the same element that differ in the number of neutrons

enzyme

catalyst that speeds up chemical reactions in cells

A chemical ________ is a substance formed by the combination of two or more elements in definite proportions.

compound

Carbohydrates

compounds made up of carbon, hydrogen, and oxygen atoms, usually in a ratio of 1:2:1

Amino acids

compounds with an amino group (-NH2) on one end and a carboxyl group (-COOH) on the other end.

Nucleotides

consist of three parts: a 5-carbon sugar, a phosphate group, and a nitrogenous base, as known in sugar, a phosphate group, and a nitrogenous base.

buffer

dissolved compound that prevents sharp swings in pH

A pure substance that consists entirely of one type of atom is called a(an) ______________ .

element

Lipids are made of

fatty acids and glycerol

Covalent Bond

forms when electrons are shared between atoms.

Adhesion

is an attraction between molecules of different substances.

Ionic Bond

is formed when one or more electrons are transferred from one atom to another.

polymer

large compound formed by the joining of small compounds, called monomers

Nucleic acids

macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus. Nucleic acids are polymers assembled from individual monomers known as nucleotides.

Proteins

macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen. Proteins are polymers of molecules called amino acids.

Suspensions

materials that do not dissolve when placed in water but separate into pieces so small that they cannot settle our. The movement of water molecules keeps the small particles suspended.

amino acid

monomer of a protein

Protons and neutrons together form the_______ ,which is at the center of the atom.

nucleus

lipid

part of waterproof coverings

Ions

positively and negatively charged atom

chemical reaction

process that produces a new set of chemicals

Enzymes

proteins that act as biological catalyst. Enzymes speed up chemical reactions that take place in cells.

reactant, product, chemical reaction

reactant, product, chemical reaction

Chemical reactions that ________ energy often occur spontaneously.

release

A fatty acid with the maximum number of hydrogen atoms possible is

saturated

monosaccharide

single sugar molecule

Monosaccharides

single sugar molecules which include galactose, which is a component of milk, and fructose, which is found in many fruits.

Nucleic acids

store and transmit hereditary or genetic information.

nucleic acid

stores and transmits genetic information

The reactants of an enzyme-catalyzed reaction are known as ___________.

substrates

Reactants

the elements or compounds that enter into a chemical reaction.

Molecules

the smallest unit of most compounds.

solvent

the substance in which the solute is dissolved in.

Solute

the substance that is dissolved

Polarity

uneven distributions of electrons between the oxygen and hydrogen atoms.

Radioactive isotopes

unstoppable nuclei and break down at a constant rate over time. The radiation these isotopes give off can be dangerous; but radioactive isotopes have a number of important scientific and practical uses.

he slight attractions that develop between the oppositely charged regions of nearby molecules are called ______________.

van der Waals forces

Buffers

weak acids or bases that can react with strong acids or bases to prevent, sharp, sudden changes in pH

Double bond

when atoms share four electrons

Triple Bond

when atoms share six electrons

Single Covalent bond

when the atoms shares two electrons