Biology Ch 3 Mouse Mischief

the size of the electrons The way in which elements bond to form compounds depends on which of the following? the size of the electrons the shape of the nucleus the number of neutrons in each atom the electrons in the atoms of the elements

In what type of bond are electrons shared? ionic nuclear covalent hydrogen

ionic nuclear covalent hydrogen What weak bond holds together the two strands of nucleotides in a DNA molecule? ionic nuclear covalent hydrogen

The substance is an acid When an unknown substance is dissolved in water, hydronium ions form. What can you conclude about the substance? The substance is a gas The substance is a bas The substance is an acid The substance is a carbohydrate

Activation energy is needed only by chemical reactions that release

In an atom, the number of protons is equal to the number of electrons.

A solution is a mixture of unevenly distributed substances

Polar substances dissolve well in water because water also is polar

Most of the chemical reactions in the body would not occur without enzymes

Atoms do not contain protons. electrons. ions.

The attraction between water molecules is caused by covalent bond hydrogen bonds ionic and covalent bonds

An atom is called an ion when it has either lost or gained electrons lost its nucleus more neutrons than protons

The ability of water to form drops is an example of adhesion. cohesion. ionic bonding

Both solutions are acidic One solution has a pH of 2, and another has a pH of 7. Which of the following is true? Both solutions are acidic The solution with a pH of 2 is basic, and the solution with a pH of 7 is acidic. The solution with a pH of 2 is acidic, and the solution with a pH of 7 is neutral.

Plants store the sun’s energy for future use as DNA starch. protein.

decrease the speed of chemical reactions. Enzymes are usually proteins. decrease the speed of chemical reactions. increase the activation energy of chemical reactions

element. atom. molecule. electron. The smallest unit of matter that cannot be broken down by chemical means is a(n) element. atom. molecule. electron.

The bonds between the atoms that make up water molecules are called covalent bond hydrogen bonds ionic and covalent bond covalent and hydrogen bonds.

An atom is called an ion when it ha either lost or gained electrons. either lost or gained protons. more neutrons than protons lost its nucleus.

A solution is a mixture of polar and nonpolar substances protons and neutrons. unevenly distributed substances. evenly distributed substances.

Water is _______ , therefore _______ substances dissolve in it. polar, nonpolar polar, polar nonpolar, polar nonpolar, nonpolar

In a chemical reaction, energy may be absorbed. released. required. All of the above

Without energy, organisms could not maintain homeostasis. carry out chemical reactions. make their own food. All of the above

The basic units of most biomolecules contain nitrogen. oxygen carbon. amino acids

Compounds are formed when atoms of an element lose an electron. atoms of an element gain an electron atoms of the same element join together. atoms of two different elements join together.

are usually carbohydrates. Enzymes are usually carbohydrates. can only catalyze a reaction onc reduce the activation energy of chemical reactions eliminate the activation energy of chemical reactions.

impossible to determine. In an atom with the same number of electrons and protons, the electrical charge is neutral. positive. negative. impossible to determine.

Activation energy is needed by chemical reactions that release energy absorb energy. are catalyzed by enzymes. All of the above

The ability of water to form drops is an example of a chemical change. cohesion. adhesion ionic bonding

What kind of bonds do water molecules form with one another? covalent hydrogen ionic Both (a) and (c)

is made of a sugar, a base, and a phosphate group Starch is made of a sugar, a base, and a phosphate group does not contain carbon atoms. is made of amino acids is a carbohydrate in which energy is stored

2. Solution B indicates a pH of 7. You conclude that 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 both solutions are acidic. solution A is basic; solution B is neutral. solution A is acidic; solution B is neutral None of the above

compound. molecule. atom. ion. An element is defined as a pure substance because it is made of only one kind of compound. molecule. atom. ion.

Atoms bond with other atoms to form compounds because electrons are attracted to each other bonding helps atoms become more stable. the nuclei of atoms are attracted to each other. bonding makes an element more pure.

When food molecules are broken down inside cells, some of the energy in the molecules is stored temporarily in proteins. RNA. DNA. ATP.

do not take part in the reaction. Enzymes that take part in a chemical reaction are not considered to be reactants because they do not take part in the reaction. are not changed by the reaction. have no valence electrons. are used up in the reaction