Chapter 2: The Chemistry of life Study Guide AACC HUMAN BIOLOGY 231

what are the subatomic particles that make up an atom?

protons, neutrons, electrons

why do isotopes of the same element have the same chemical properties?

because they have the same number of electrons

what are the main types of chemical bonds?

covalent, ionic, hydrogen

Atom

the basic unit of matter

Nucleus

formed by the strong binding of protons and neutrons at the center of an atom

Electron

a negatively charged particle

Element

a pure substance that consists entirely of one type of atom

Isotopes

atoms of the same element that have different number of neutrons that they usually contain

Compound

a substance formed by the chemical combination of 2 or more elements in definite proportions

Ionic Bond

formed when electrons are transferred from one atom to another

Ions

positively and negatively charged atoms

Covalent Bonds

formed by electrons moving about the nuclei of both atoms

Molecule

the smallest unit of all compounds

van der Waals forces

the slight attraction that can develop between the oppositiley charged areas of nearby molecules

Hydrogen Bond

the attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge

Cohesion

an attraction between molecules of the same substance

Adhesion

attraction between molecules of different substances

Solution

type of mixture in which all the components are evenly distributed

Solute

substance that dissolves in a solution

Solvent

dissolves the solute in a solution

Suspensions

mixtures of water and non dissolved materials, they seperate

pH scale

scale with values from 0-14 used to measure the concentration of h+ ions in a solution, a pH of 0-7 is acidic and a pH of 7-14 is basic

Acid

any compound that forms hydrogen ions in a solution

Base

comund that produces hydroxide ions in solution

Buffers

weak acids or bases that can react with strong acids or bases to pent sharp, suddent changes in pH

What does it mean to say "water is a polar molecule"?

it is able to form multiple hydrogen bonds which account for many of its special properties

What is the ability of waters polarity?

to dissolve both ionic compounds and other polar molecules

What role do buffers play in maintains homeostasis in organisms?

buffers prevent sharp, sudden changes in pH

What are the elements with which carbon can bond?

phosphorus, hydrogen, oxygen, nitrogen, sulfur

What to living things use as their main source of energy?

carbohydrates

What do plants use carbohydrates for?

structural purposes

What are lipids used for?

used to store energy, some lipids are important parts of biological membranes and waterproof coverings

What do nucleic acids do?

store and transmit heredity or genetic information

What is the role of proteins?

control the rate of reactions and regulate cell process, some build tissues such as bone and muscle and some transport materials or help to fight diseases

Monomers

small chemical units that make up a polymer

Polymer

molecules combed of many monomers that make up macromolecules

Carbohydrates

compounds made up of carbon, hydrogen, and oxygen atoms IN A RATIO OF 1:2:1

Monosaccharides

simple sugar molecules

Lipids

a large and varied group of biological molecules that are generally NOT soluble in water, they are made mostly from carbon and hydrogen atoms.
examples: wax, oil, and fats

Nucleic Acids

macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus

What are the 3 main parts of a nucleotide?

carbon sugar, phosphate group, and a nitrogen base

Protein

macromolecules that contain nitrogen as well as carbon,hydrogen and oxygen

Amino Acids

compunds with amino group on one end and a carbonyl group on the other end

What do chemical reactions always involve?

changes in the chemical bond that joins atoms in compounds

What is the difference between chemical reactions that release energy, and chemical reactions that absorb energy?

chemical reactions that release energy: often occur spontaneously
chemical reactions that absorb energy: will not occur without a source of energy

What is an enzyme's job?

to speed up the chemical reactions that occur in cells

What three things affect the activity of enzymes?

temperature, pH, regulatory molecules

Chemical Reaction

a process that changes or transforms one set of chemicals into another

Reactants

the element or compound that enters into a chemical reaction

Products

the elements and compounds produced by a chemical reaction

Activation Energy

energy that is needed to get the reaction started

Catalysts

a substance that speeds up the rate of a chemical reaction

Enzymes

proteins that act as biological catalysts

Substrates

the reactants of enzyme-catalyzed reactions

What are 2 differences between carbon-12 and carbon-14

carbon-12 is not radioactive and has an equal number of protons.
carbon-14: radioactive and has 8 neutrons

What are two ways that carbon-12, carbon-13, and carbon-14 are alike?

all have 6 protons and 6 electrons

A chemical element is a pure substance that consists entirely of one type of __.

atom

What is the difference between an ionic and a covalent bond?

ionic: transfers electrons
covalent: shares electrons

How are chemical bonds important in metabolism?

organisms build up and break down materials for energy through chemical reactions and chemical bonds

True or false: water is a polar molecule

true

True or false: hydrogen bonds are an example of adhesion

false

True or false: covalent bonds give water a low heat capacity

false

True or false: a hydrogen bond is stronger than a covalent bond?

false

What makes pure water neutral?

the positive changes in its 10 protons balance out the negative charges in its 10 electrons

How would you buffer a solution that has a pH of 12?

By adding a weak acid to decrease the pH

How many valence electrons does each carbon atom have?

4 valence electrons

Many of the molecules in the living cells are so large that they are called ___.

macromolecules

What is released of absorbed whenever chemical bonds ad formed or broken?

energywhatever by

How does the addition of a catalyst affect biochemical reactions?

enzymes speed up the chemical reactions tht take place in cells

What type of catalysts affect biochemical reactions?

enzymes

What makes proteins the ideal types of compounds to act as enzymes?

they lower the activation energy and that has a dramatic affect on how quickly the reaction is completed

In terms of an organism and how it interacts with its environment, what is the benefit of having controls on the chemical reactions that take place in its body?

a living organism lives in an unstable and extreme environment, and it can can still function and live because of the internal chemical reaction and control.