BIO-111 Exam 2 practice questions

What are the 4 major types of macromolecules present in cells?

proteins, carbohydrates, lipids, nucleic acids

What are the monomer subunits of proteins?

amino acids

What are the monomer subunits of lipids?

glycerol and fatty acids

What are the monomer subunits of carbohydrates?

monosaccharides

What are the monomer subunits of nucleic acids?

nucleotides

What is a condensation reaction?

When two molecules bond through the loss of a water molecule.

What is a hydrolysis reaction?

A covalent bond is broken by adding a molecule of water.

What functions do carbohydrates serve?

energy storage, structure

What are three main polysaccharides composed of glucose?

starch, glycogen, cellulose

What is the function of starch? Does it branch?

energy storage in plants; moderate branching

What is the function of cellulose? Does it branch?

keeping structure in plants; no branching

What is the function of glycogen? Does it branch?

energy storange in animals and fungi; lots of branches

Which macromolecule is primarily hydrocarbons?

lipids

What functions do lipids serve?

insulation

What quality of phospholipids allows them to form bilayers?

amphipathic

What is the function of a hydroxyl group?

forms hydrogen bonds with water to help dissolve molecules; enables linkage to other molecules by condensation

What is the function of a phosphate group?

enters into condensation reactions by giving up --OH

What is the function of an amino group?

accepts H+ in living tissue; enters into condensation reactions by giving up H+

What is the function of a carboxyl group?

ionizes in living tissues to form --COO- and H+; enters condensation reactions by giving up H+

Nonpolar amino acid side chains contain a lot of what atom?

Carbon atoms

Polar uncharged amino acid side chains contain what atom?

oxygen

How do polar uncharged amino acid side chains interact with molecules?

Polar bonds; hydrophilic; hydrogen bonds

Interact w/ other molecules through hydrogen bonds

Uncharged; No interaction with ions

How do nonpolar amino acid side chains interact with molecules?

No polar bonds' Cannot form hydrogen bonds w/ water

Interact with nonpolar molecules (often with other hydrophobic R group amino acids)

Cluster in center of proteins; interact with fatty acid tails of phospholipids

How do positively charged amino acid side chains interact with molecules?

Interact with negatively charged molecules

Hydrophilic; interact with water

How do negatively charged amino acid side chains interact with molecules?

Interact with positively charged molecules

Hydrophilic; interact with water

What is special about cysteine?

-SH group can react with another cysteine side chain to form disulfide bridge ( –S—S– )

Important in protein folding

What is special about proline?

Proline side chain forms a ring

Limits its ability to rotate around the alpha carbon.

Often found where a protein bends or loops (in polypeptide chain)

What is special about glycine?

Just a H in the R group

Small, fits into tight corners in the interior of proteins

How are peptide bonds formed?

condensation reaction

What is the distinction between the N-terminus and C-terminus of a polypeptide?

N-terminus has the amino group, C-terminus has the carboxyl group

What bond holds amino acids together?

peptide bond

Where is the bond of amino acids formed?

between the carboxyl group of one amino acid and the amino group of another amino acid

What is the primary structure of proteins?

sequence of amino acids

What is the secondary structure of proteins?

alpha helix or beta pleated sheet

What is the tertiary structure of proteins?

overall 3D shape of a protein

What is the quaternary structure of proteins?

when a protein is made up of more than one polypeptide chain

What quality of proteins is important in determining the types of functions of that protein?

shape

What is denaturing?

Denaturing is where high temperatures and extreme pH's make enzymes change shape

What reaction joins nucleotides together?

condensation reaction

What bond holds nucleotides together?

phosphodiester bonds

What groups is a phosphodiester bond between?

phosphate group of 5' carbon of one sugar to the 3' carbon on the second sugar

What is the 5' end?

no new nucleotides can be added

What is the 3' end?

new nucleotides ONLY added at 3' end

What are the complementary base pairs?

A-T

G-C

What are purines?

Adenine (A) Guanine (G)

double ring

What are pyrimidines?

Cytosine (C)

Thymine (T)

Uracil (U)

single ring

What bonds are base pairs held together by?

hydrogen bonds

Who discovered complementary base pairs?

Chargaff

What did Franklin do?

made X-ray diffraction photos of DNA; discovered double stranded helix with 10 nucleotides in each full turn

What did Watson and Crick do?

Built models using cardboard and wire to understand the structure of DNA

How many strands does DNA have?

two

What kind of helix is DNA?

right-handed

DNA strands run ________ to each other

antiparallel

What holds DNA strands together?

hydrogen bonds between bases

What did Griffith do? What did he find?

work on two strains of Streptococcus pneumoniae; discovered that a substance from cells of one strain (even when dead) could produce a heritable change in the other strain (Transformation)

What did Avery do? What did he find?

used the transformation experiment to determine which molecule was transforming the bacteria; DNase, RNase, Protease; concluded that DNA was the transforming substance

What did Hershey and Chase do? What did they find?

used bacteriophage T2 virus to determine whether DNA, or protein, is the genetic material; 32P (DNA) and 35S (protein) to label virus, found that DNA went inside pellet and transformed, therefore DNA must be the genetic material

DNA reproduces itself through what process?

replication

DNA sequences can be copied into RNA through what process?

transcription

RNA can specify a sequence of amino acids in a polypeptide through what process?

translation