Name:______Date:______Period:______

Chapter 6 – Chemistry in Biology

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Section 1: Atoms, Elements, and Compounds

Section 2: Chemical Reactions

Section 3: Water and Solutions

Section 4: The Building Blocks of Life

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6.1 Atoms, Elements, and Compounds

Atoms:

  • Chemistry is the study of ______.
  • ______are the building blocks of matter.
  • ______and ______are located at the center of the atom.
  • Protons are ______charged particles
  • Neutrons are particles that have ______.
  • Electrons are ______charged particles that are located outside the nucleus.

Elements

  • An element is a ______that cannot be broken down into other substances by physical or chemical means.
  • There are over 100 known elements, ______of which occur naturally.
  • Each element has a unique name and symbol.
  • The Periodic Table of Elements
  • Horizontal rows are called ______.
  • Vertical columns are called ______.

Isotopes

  • Atoms of the same element that have the ______number of protons and electrons but have a ______number of neutrons

Radioactive Isotopes

When a ______breaks apart, it gives off radiation that can be detected and used for many applications.

Compounds

  • A pure substance formed when two or more ______elements combine
  • Compounds are always formed from a specific combination of elements in a fixed ratio.
  • Compounds cannot be broken down into simpler compounds or elements by ______means.
  • List some physical changes that can be made to compounds without change:

Chemical Bonds

1)Covalent bonds -Chemical bond that forms when electrons are ______

  1. A molecules is a compound in which the atoms are held together by covalent bonds

2)Ionic Bonds

  1. Ionic Bonds - Electrical attraction between two oppositely charged atoms or groups of atoms
  2. Some atoms tend to donate or accept electrons more easily than other atoms.

The elements identified as metals tend to ______electrons.

The elements identified as nonmetals tend to ______electrons.

c. Most ionic compounds are ______at room temperature and have higher melting points than molecular compounds formed by covalent bonds.

3)van der Waals Forces

  1. When molecules come close together, the ______forces between slightly positive and negative regions pull on the molecules and hold them together.
  2. The ______of the attraction depends on the size of the molecule, its shape, and its ability to attract electrons. The ability of geckos to climb on sheer surfaces is attributed to van der Waals force. A gecko can hang on a glass surface using only one toe.
  3. It is important to remember that van der Waals' forces are forces that exist between MOLECULES of the same substance. (two H2O molecules – H-bonding)

6.2 Chemical Reactions

A chemical reaction is the process by which atoms or groups of atoms in substances are reorganized into different substances.

  • Clues that a chemical reaction has taken place include the production of heat or light, and formation of a gas, liquid, or solid.
  • 4Fe + 3O2 = 2Fe2O3. A chemical reaction occurs when atoms join together or break apart to form new and different combinations of atoms

iron / + / water / + / air / = / rust
Fe / + / H2O / + / O2 / / Fe2O3

Chemical Equations

Chemical formulas describe the substances in the reaction and arrows indicate the process of change. ______are the starting substances, on the left side of the arrow

______are the substances formed during the reaction, on the right side of the arrow (draw)

  • Glucose and oxygen react to form carbon dioxide and water. (write out a generalized reaction for aerobic respiration)

Balanced Equations

  • The ______states matter cannot be created or destroyed.
  • The ______of atoms of each element on the ______side must equal the ______of atoms of the same element on the ______side. Write out the balanced equation for aerobic respiration.

Energy of Reactions

  • The ______energy is the minimum amount of energy needed for reactants to form products in a chemical reaction.

This reaction is ______and released heat energy.

The energy of the ______is ______than the energy of the reactants.

This reaction is ______and absorbed heat energy

  • The energy of the ______is ______than the energy of the reactants.

Enzymes

A ______is a substance that lowers the activation energy needed to start a chemical reaction. Enzymes are usually proteins.

Enzymes does not increase ______product is made and it does not get ______in the reaction.

Enzymes are biological catalysts, usually made of proteins.

  • The reactants that bind to the enzyme are called ______.
  • The specific location where a substrate binds on an enzyme is called the ______
  • The ______changes shape and forms the enzyme-substrate complex, which helps chemical bonds in the reactants to be broken and new bonds to form.
  • Factors such as ______, ______, and other ______affect enzyme activity.

6.3 Water and Solutions

Water and Polarity

Molecules that have an unequal distribution of charges are called polar molecules. ______is the property of having two opposite poles. (positive and negative)

A hydrogen bond is a weak interaction involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom

Homogenous Mixtures

A mixture that has a uniform composition throughout

A ______is a substance in which another substance is dissolved

A ______is the substance that is dissolved in the solvent.

Heterogeneous Mixtures

  • In a ______mixture, the components remain distinct.

Acids and Bases

Substances that release ______(H+) when dissolved in water are called acids.

Substances that release ______(OH–) when dissolved in water are called bases.

  • The measure of concentration of H+ in a solution is called pH.
  • Acidic solutions have pH values______than 7, which means higher H+ concentration.
  • Basic solutions have pH values ______than 7, which means lower H+ concentrations.
  • ______are mixtures that can react with acids or bases to keep the pH within a particular range.

6.4 The Building Blocks of Life

Organic Chemistry

  • The element ______is a component of almost all biological molecules.
  • Carbon has four electrons in its outermost energy level.
  • One carbon atom can form ______with other atoms.
  • Carbon compounds can be in the shape of:

straight chains, branched chains, or rings.

Macromolecules

  • Carbon atoms can be joined to form carbon molecules.
  • ______are large (______) molecules formed by joining smaller organic molecules together
  • ______are molecules made from repeating units of identical or nearly identical compounds linked together by a series of covalent bonds.

Table of Biological Macromolecules

Group / Function
  • Stores energy
  • Provides structural support

  • Stores energy
  • Provides steroids
  • Waterproofs coatings

  • Transports substances
  • Speeds reactions
  • Provides structural support
  • Provides hormones

  • Stores and communicates genetic information

Carbohydrates

  • Compounds composed of carbon, hydrogen, and oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom—(CH2O)n
  • Values of n ranging from three to seven are called simple sugars, or monosaccharides.
  • Two ______joined together form a ______.
  • Longer carbohydrate molecules are called ______.
  • Animals store energy as ______in liver and muscle cells for immediate energy. Do you think glycogen would be a monosaccharide or a polysaccharide?
  • Plants store energy as starch. Do you think glycogen would be a monosaccharide or a polysaccharide?

Lipids

  • Molecules made mostly of carbon and hydrogen
  • A triglyceride lipid is a fat if it is solid at room temperature and oil if it is liquid at room temperature.
  • Lipids that have tail chains with only single bonds between the carbon atoms are called ______(less healthy).
  • Lipids that have at least one double bond between carbon atoms in the tail chain are called ______fats (more healthy unless partially hydrogenated like “trans-fats” then very unhealthly). Fats with more than one double bond in the tail are called polyunsaturated fats.

Proteins

  • Are made of monomers called ______.
  • Amino acids are small compounds that are made of carbon, nitrogen, oxygen, hydrogen, and sometimes sulfur.
  • Amino acids have a central carbon atom.One of the four carbon bonds is with hydrogen.
  • The other three bonds are with an amino group (–NH2), a carboxyl group (–COOH), and a variable group (–R).
  • The number and the order in which the amino acids are joined define the protein’s ______structure. After an amino acid chain is formed, it folds into a unique three-dimensional shape, which is the protein’s ______structure.

Essential amino acids

•Humans can produce _____of the 20 amino acids. The others must be supplied in the food.

•Failure to obtain enough of even 1 of the 10 essential amino acids, those that we cannot make, results in ______of the body's proteins—muscle and so forth—to obtain the one amino acid that is needed.

•Unlike fat and starch, the human body does not store excess ______for later use—the amino acids must be in the food every day.

Nucleic acids

Nucleic acids are complex macromolecules that store and transmit genetic information

  • Nucleic acids are made of smaller repeating subunits called nucleotides, composed of carbon, nitrogen, oxygen, phosphorus, and hydrogen atoms.

DNA:______

RNA: ______

•DNA contains four different nucleotide bases: ______(A), ______(C), ______(G), and ______(T).

•RNA contains the bases adenine (A), cytosine (C), and guanine (G); however, RNA does not contain thymine, instead, RNA's 4thnucleotide is the base ______(U).

•Unlike the double-stranded ______molecule, ______is a single-stranded molecule.

Diagnostic Questions

1)Which of the following particles is negatively charged?

2)Isotopes are created by a change in the number of what particle of an atom?

3)Identify the proteins that speed up the rate of chemical reactions.

4)What particles are in an atom’s nucleus?

5)What causes the overall charge of an atom to be zero?

6)What type of substance is water?

7)What provides the energy for all living processes?

8)Which is a chemical reaction?

9)Which chemical reaction is endothermic?

10)How does an enzyme increase the rate of a chemical reaction?

11)Why is water able to dissolve a wide variety of solutes?

12)What type of bonds attracts water molecules to each other and to other substances?

13)Which ion, when released in water, causes a solution to be basic?

14)What is the name for a substance that keeps the pH in cells within the 6.5 to 7.5 pH range?

15)Which element do almost all biological molecules contain?

16)How many covalent bonds can carbon form with other atoms?

17)What type of biological molecule is an enzyme?

18)What are fats, oils, and waxes composed of?

19)What are the monomers that make up proteins?

20)Which biological molecule transports substances between cells?

21)Look at the following figure. Determine what the upward curve represents.

22)Explain why chemical equations must be balanced.

23)Which is a result of van der Waals forces?

24)What is true of this chemical reaction?

25)Which fruit contains a higher concentration of hydrogen ions?

26)What do cellulose and chitin have in common?

27)Which polysaccharide stores energy in muscle and liver tissue?

28)What is the function of this biological macromolecule?

29)Which is a characteristic of all lipids?

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