AP Biology Unit 2

A scientist observes a base sequence of AGCTAGCTAGCT.  Which of the following would be the complimentary strand?

• TGCATGCATGCA

• TCGATCGATCGA

• TAGCTAGCTAGC

• TTAAGGCCTTCC

What is A?

• Leading strand

• Lagging strand

• Okazaki Fragments

• DNA plymerase

The separation of the two single strands of DNA creates a ‘Y’ shape?

• enzyme

• unzip

• A replication fork

Which enzyme proofreads and removes RNA Primase

• Ligase

• Polymerase 1

• Polymerase 3

• Helicase

According to the fluid mosaic model of cell membranes, phospholipids___________________.

• can shift laterally along the plane of the membranee

• frequently flip-flop from one side of the membrane to the other

• occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane

• have hydrophilic tails in the interior of the membrane

Which of the following types of molecules are hydrophilic and therefore excluded from the hydrophobic portion of the phospholipid bilayer?

• transmembrane proteins

• integral membrane proteins

• peripheral proteins

• cholesterol

In what way do the membranes of a eukaryotic cell vary?

• Phospholipids are found only in certain membranes

• Certain proteins are unique to each membrane

• Only certain membranes of the cell are selectively permeable

• Some membranes have hydrophobic surfaces exposed to the cytoplasm while others have hydrophilic surfaces facing the cytoplasm.

Which of the following statements describes a characteristic feature of a carrier protein in a plasma membrane?

• It exhibits specificity for a particular type of molecule

• It requires the expenditure of cellular energy to function.

• It works against diffusion.

• It has not hydrophobic regions.

Which of the following would likely diffuse through the lipid bilayer of a plasma membrane most rapidly?

• sucrose.

• an amino acid.

• O₂.

• Na⁺.

Which of the following statements about diffusion is true?

• It is very rapid of long distances.

• It requires an expenditure of energy by the cell.

• It is an active process in which molecules move from a region of lower concentration to a region of higher concentration.

• It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.