Biology Chapter 2: Chemistry of Life Flashcards

Questions and Answers

What is the basic unit of matter called?

atom

Describe the nucleus of an atom.

center of an atom, made of protons and neutrons

What are protons?

positive charge and found in the nucleus

What are neutrons?

neutral charge and found in the nucleus Signup and view all the answers

What are electrons?

negative charge and is surrounding the nucleus Signup and view all the answers

Why are atoms neutral despite having charged particles?

because the number of protons are equal to the number of electrons Signup and view all the answers

What is a chemical element?

a pure substance that only consists of one type of atom Signup and view all the answers

What does an element's atomic number represent?

the number of protons Signup and view all the answers

Atoms of the same element that differ in the number of neutrons are known as?

isotopes Signup and view all the answers

How are isotopes identified?

by their mass number Signup and view all the answers

Why do all isotopes of an element have the same chemical properties?

they have the same number of electrons and protons Signup and view all the answers

What is a chemical compound?

substance composed of atoms of 2 or more different elements that are chemically combined Signup and view all the answers

What holds atoms in a compound together?

chemical bond Signup and view all the answers

What is a covalent bond?

formed when electrons are shared between atoms Signup and view all the answers

What is an ionic bond?

formed when one or more electrons are transferred from one atom to another Signup and view all the answers

What is an ion?

an atom that gains or loses an electron, giving it a new charge Signup and view all the answers

An atom that loses electrons has a negative charge.

False Signup and view all the answers

What is the structure that results when atoms are joined together by covalent bonds called?

molecule Signup and view all the answers

True or false: In a water molecule, each hydrogen atom forms a single covalent bond.

true Signup and view all the answers

What are the slight attractions that develop between oppositely charged regions of nearby molecules called?

van der Waals forces Signup and view all the answers

A water molecule is neutral.

True Signup and view all the answers

Why is a water molecule polar?

the unequal sharing of electrons Signup and view all the answers

True or false: The attractions between the hydrogen atom on one water molecule and the oxygen atoms on another water molecule is an example of hydrogen bonds.

true Signup and view all the answers

What is cohesion?

attraction between molecules of the same substance Signup and view all the answers

What is adhesion?

attraction between molecules of different substances Signup and view all the answers

What is a mixture?

different substances that are not chemically combined Signup and view all the answers

A mixture of two or more substances in which the molecules of the substances are evenly mixed is called a?

solution Signup and view all the answers

What is the greatest solvent in the world?

water Signup and view all the answers

What is suspension?

heterogeneous mixture in which salt-like particles settle out of a solvent-like phase Signup and view all the answers

What is a solute?

it's what is getting dissolved Signup and view all the answers

What is a solvent?

it's what does the dissolving Signup and view all the answers

Why is water neutral despite the production of hydrogen ions and hydroxide ions?

the number of positive hydrogen ions is equal to the number of negative hydroxide ions Signup and view all the answers

What does the pH scale indicate?

how acidic or how basic a solution is Signup and view all the answers

How many more H+ ions does a solution with a pH of 4 have than a solution with a pH of 5?

5 more Signup and view all the answers

What is an acid?

any compound that forms H+ ions in a solution Signup and view all the answers

Strong bases have pH values ranging from 11-14.

False Signup and view all the answers

What are buffers?

weak acids or bases that can react with strong acids or bases Signup and view all the answers

How many valence electrons does each carbon atom have?

4 Signup and view all the answers

What gives carbon the ability to form chains that are almost unlimited in length?

valence electrons Signup and view all the answers

Many of the molecules in living cells are so large that they are known as?

macromolecules Signup and view all the answers

What is the process called by which macromolecules are formed?

polymerization Signup and view all the answers

When monomers join together, what do they form?

polymers Signup and view all the answers

What are the 4 groups of organic compounds found in living things?

carbohydrates, proteins, lipids, nucleic acids Signup and view all the answers

What atoms make up carbohydrates?

C, H, O Signup and view all the answers

Simple sugar molecules are also called?

monomers Signup and view all the answers

What are monosaccharides?

galactose, glucose, fructose Signup and view all the answers

What are polysaccharides?

many monosaccharides combined together Signup and view all the answers

How do plants and animals store excess sugar?

in glycogen Signup and view all the answers

What kinds of atoms are lipids mostly made of?

C, H, O Signup and view all the answers

What are 3 common categories of lipids?

fats, oils, waxes Signup and view all the answers

Many lipids are formed when glycerol molecules combine with compounds called?

monomers Signup and view all the answers

What does saturated mean in relation to lipids?

each carbon atom in a lipid's fatty acid chain is joined to another carbon atom by a single bond Signup and view all the answers

What does unsaturated mean in relation to lipids?

there is at least one carbon-carbon double bond in a fatty acid Signup and view all the answers

What does polyunsaturated mean in relation to lipids?

a lipid's fatty acids contains more than one double bond Signup and view all the answers

What kind of atoms do nucleic acids contain?

H, O, N, C, P Signup and view all the answers

The monomers that make up nucleic acids are known as?

nucleotides Signup and view all the answers

A nucleotide consists of what 3 parts?

5-carbon sugar, phosphate group, and nitrogen base Signup and view all the answers

What is a function of nucleic acids in living things?

transmit hereditary or genetic info Signup and view all the answers

What are the 2 kinds of nucleic acids?

DNA and RNA Signup and view all the answers

Proteins contain which kinds of atoms?

H, O, N, C Signup and view all the answers

Proteins are polymers of molecules called?

amino acids Signup and view all the answers

What are 4 roles that proteins play in living things?

structure, contracting muscle tissue, transport oxygen in blood Signup and view all the answers

What is a chemical reaction?

a process that changes or transforms one set of chemicals into another Signup and view all the answers

What are reactants?

starting materials in a chemical reaction Signup and view all the answers

What are products?

the new substances that are formed in a chemical reaction Signup and view all the answers

Chemical reactions always involve changes in chemical?

bonds Signup and view all the answers

What is released or absorbed whenever chemical bonds form or are broken?

energy Signup and view all the answers

What do chemical reactions that absorb energy need to occur?

they need a source of energy Signup and view all the answers

Chemists call the energy needed to get a reaction started the?

activation energy Signup and view all the answers

What is a catalyst?

a substance that speeds up the rate of a chemical reaction Signup and view all the answers

Proteins that act as biological catalysts are called?

enzymes Signup and view all the answers

What do enzymes do?

speed up chemical reactions that take place in cells Signup and view all the answers

The reactants of enzyme-catalyzed reactions are known as?

substrates Signup and view all the answers

Why are the active site and the substrates in an enzyme-catalyzed reaction compared to a lock and key?

because the fit is so precise Signup and view all the answers

The binding together of an enzyme and a substrate forms a?

enzyme-substrate complex Signup and view all the answers

How do most cells regulate the activity of enzymes?

most cells contain proteins that help turn key enzymes 'on' and 'off' Signup and view all the answers

Study Notes

Basic Units of Matter

The smallest unit of matter is called an atom.
Atoms consist of a nucleus containing protons (positive charge) and neutrons (neutral charge).
Electrons with a negative charge orbit around the nucleus.

Atomic Structure and Properties

Atoms remain neutral when the number of protons equals the number of electrons.
An element is defined as a pure substance made of only one type of atom.
An element's atomic number indicates the number of protons it has.
Isotopes are variants of the same element with differing neutron counts, identified by their mass number.
All isotopes of an element exhibit similar chemical properties due to identical electron and proton counts.

Chemical Compounds and Bonds

A chemical compound forms when atoms of different elements chemically combine.
Atoms in a compound are held together by chemical bonds:
- Covalent bonds involve sharing electrons.
- Ionic bonds occur when electrons are transferred between atoms.

Ions and Molecules

An ion is an atom that has gained or lost electrons, resulting in a charge.
A molecule is created when atoms are bonded through covalent means.

Water and Its Properties

Water molecules are neutral overall despite the presence of charged hydrogen and hydroxide ions due to equal positive and negative charges.
A water molecule is considered polar due to the unequal sharing of electrons, leading to an electrical charge distribution.
Hydrogen bonds form due to attractions between hydrogen atoms of one water molecule and oxygen atoms of another.

Mixtures and Solutions

A mixture consists of substances that are not chemically combined, leading to various types:
- Solutions are uniform mixtures of two or more substances.
- Suspensions contain particles that settle out, forming a heterogeneous mixture.
Water is identified as the greatest solvent due to its ability to dissolve numerous substances.

Acids, Bases, and pH

The pH scale measures how acidic or basic a solution is, with lower values being more acidic.
An acid produces H+ ions in solutions, while buffers help maintain pH by reacting with strong acids or bases.

Organic Compounds and Macromolecules

Carbon atoms possess four valence electrons, allowing for diverse bonding and creating extended chains.
Macromolecules are large molecules formed through polymerization, where smaller units called monomers join to form polymers.
Four primary groups of organic compounds: carbohydrates, proteins, lipids, and nucleic acids.

Carbohydrates, Lipids, Nucleic Acids, and Proteins

Carbohydrates are composed of carbon (C), hydrogen (H), and oxygen (O); simple sugars are called monosaccharides.
Lipids mainly consist of C, H, and O, classified into fats, oils, and waxes.
Nucleic acids include DNA and RNA, built from nucleotides which consist of a sugar, phosphate, and nitrogen base.
Proteins are polymers formed from amino acids, playing roles in structure, muscle contraction, and oxygen transport.

Chemical Reactions

A chemical reaction transforms one set of chemicals into another, involving changes in chemical bonds.
Reactants are starting materials, while products are formed substances after the reaction.
Chemical reactions can absorb or release energy, with activation energy being necessary to initiate reactions.

Enzymes and Catalysis

Catalysts accelerate chemical reactions, while enzymes are biological catalysts that enhance reaction rates in cells.
Enzyme-substrate interactions are highly specific, often described as a lock and key mechanism based on precise fits.
The combination of an enzyme and a substrate forms an enzyme-substrate complex, facilitating the conversion of substrates into products.

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Test your knowledge on the basics of biology with these flashcards focused on Chapter 2: The Chemistry of Life. You'll cover essential concepts such as atoms, protons, neutrons, and electrons. Perfect for students wanting a quick review before exams.