Chapter 2 practice quiz

If a substance contains two or more elements of different types, it is considered a. a compound b. a monomer c. a molecule d. organic

a. a compound explanation: b. a monomer- is a subunit for a macromolecule (ex, monosaccharide is a monomer for carbohydrates) c. a molecule- is a chemical substance resulting from the combination of two or more atoms d. Organic - a term used to describe certain molecules that contain carbon bonded to hydrogens, or sometimes oxygen, nitrogen & phosphorous.

DNA is a hereditary molecule that is composed of a. deoxyribose, phosphate, and nitrogen bases b. deoxyribose, a pentose, and nucleic acids c. sugar, proteins, and thymine d. adenine, phosphate, and ribose

a. deoxyribose, phosphate, and nitrogen bases sugar phosphate- backbone nitrogen bases-( adenine, thymine, guanine, and cytosine) + deoxyribose *think of Deoxyribose for the D in DNA *think of nitrogen for the N in DNA *think of sound of "a" in phosphate for A in DNA

An atom that can donate electrons during a reaction is called a. an oxidizing agent b. a reducing agent c. an ionic agent d. an electrolyte

b. a reducing agent. (the atom that reduces the other atom accepting the electrons) explanation: a. an oxidizing agent: is an atom that accepts the electrons from the other atom and is the atom that is being reduced; when it accepts electrons it becomes slightly negative therefor it is considered reduced. The other atom(reducing agent) gives the electrons to this atom(oxidizing agent which becomes more positive therefor is oxidized) c. an ionic agent- not apart of the redox reactions or transfer of electrons. d. an electrolyte- result when substances such as salts, acids, and bases are dissolved in water and release ions.

The monomer unit of polysaccharides such as starch and cellulose is a. fructose b. glucose c. ribose d. lactose

b. glucose ( polysaccharides as well as disaccharides are linked by glycosidic bonds)

A solution with a pH of 2 ----- than a solution with a pH of 8 a. has less H+ b. has more H+ c. has more OH- d. is less concentrated

b. has more H+ explanation: (refer to explanation of question 9)

Fructose is a type of a. disaccharide b. monosaccharide c. polysaccharide d. amino acid

b. monosaccharide is a monomer for carbohydrates( fructose is a monosaccharide; it is not combined with other simple sugars) explanation: a. disaccharide-two monosaccharides such as lactose(glucose + galactose) or sucrose (table sugar)-( fructose + glucose) c. polysaccharide-a long chain of monosaccharides such as starch (storage for plants), glycogen(storage for animals) cellulose(cell wall of plants) d. amino acid- is the monomer for proteins, not carbohydrates.

Electrons move around the nucleus of an atom in pathways called a. shells b. orbitals c. circles d. rings

b. orbitals

RNA plays an important role in what biological process? a. replication b. protein synthesis c. lipid metabolism d. water transport

b. protein synthesis

The ----- charge of a proton is exactly balanced with the ----- charge of a ( an) ----- a. negative, positive, electron b. positive, neutral, neutron c. positive, negative, electron d. neutral, negative, electron

c. Positive, Negative, electron so The positive charge of a proton is exactly balanced with the negative charge of an electron. explanation: Protons have a positive (p+) charge electrons have a negative (n-) charge

A hydrogen bond can form between -----adjacent to each other. a. two hydrogen atoms b. two oxygen atoms c. a hydrogen atom and an oxygen atom d. negative charges

c. a hydrogen atom and an oxygen atom (refer to image)

The smallest unit of matter with unique characteristics is a. an electron b. a molecule c. an atom d. a proton

c. an atom explanation: a. an electron is a negatively charged sub particle located outside of the nucleus of an atom. b. a molecule is a chemical substance resulting from the combination of two or more atoms. d. A proton is a positively charged sub particle inside the nucleus of an atom.

Proteins are synthesized by linking amino acids with ----bonds a. disulfide bonds b. glycosidic c. cysteine d. serine

c. cysteine

The amino acid that accounts for disulfide bonds in the tertiary structure of proteins is a. tyrosine b. glycine c. cysteine d. serine

c. cysteine

Which part of an element does not vary in number? a. electron b. neutron c. proton d. all of these vary

c. proton ( always the same, an elements atomic number is the number of protons, ex. H1, C6) explanation: a. electron- electrons can be shared and transferred from one atom to another resulting in varied numbers of electrons in elements. b. neutron- There are isotopes of certain elements in which the there is a different number of neutrons for the same element. d. all of these vary-a & b make this option not true

In a solution of NaCl and water, NaCl is the ---- and water is the ---- a. acid, base b. base, acid c. solute, solvent d. solvent, solute

c. solute, solvent so: In a solution of NaCl is the solute and water is the solvent explanation: c/d: Solute/solvent *solute is a solid, liquid or gas that is dissolved in the solvent. *solvent is usually a liquid (water) a/b: acid, base; *acid is a chemical containing lots of H+ ions has pH 0<a<7 *base is a chemical containing lots of OH- ions has pH 7<b<14

a phospholipid contains a. three fatty acids bound to glycerol b. three fatty acids, a glycerol, and a phosphate c. two fatty acids and a phosphate bound to glycerol d. three cholesterol molecules bound to glycerol

c. two fatty acids and a phosphate bound to glycerol ( refer to image)

bond formation in polysaccharides and polypeptides is accompanied by the removal of a a. hydrogen atom b. hydroxyl ion c. carbon atom d. water molecule

d. a water molecule

Proteins can function as a. enzymes b. receptors c. antibodies d. a, b, and c

d. a, b, and c

Bonds in which atoms share electrons are defined as ----- bonds. a. Hydrogen b. ionic c. double d. covalent

d. covalent explanation: a. Hydrogen bond- does not share or transfer electrons, rather it is a chemical reaction in which there is an electrostatic force between hydrogens covalently bonded to other molecules and oxygen or nitrogen on the same molecule or a different molecule. b. ionic bond- does not share electrons, instead there is a complete transfer of electrons from one atom to another usually involving atoms that can readily donate or accept electrons. c. double- is just a term to describe the amount of electrons shared between two atoms bonded in which there is a double bond of electrons between two atoms.

What is meant by the term DNA replication a. synthesis of nucleotides b. cell division c. interpretation of the genetic code d. the exact copying of the DNA code into two new molecules

d. the exact copying of the DNA code into two new molecules.