1. Biology Ch 3
Mouse Mischief

2. 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

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

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

5. 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

6. Activation energy is needed only by chemical reactions that release

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

8. A solution is a mixture of unevenly distributed substances

9. Polar substances dissolve well in water because water also is polar

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

11. Atoms do not contain
protons.
electrons.
ions.

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

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

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

15. 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.

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

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

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

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

20. 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.

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

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

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

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

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

26. 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.

27. 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.

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

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

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

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

32. 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

33. 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

34. 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.

35. 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.

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

37. 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