Questions from previous exams Flashcards
In a bacterium, we will find DNA in _____.
the nucleoid
Cell membranes are asymmetrical. Which of the following statements is the most likely explanation for the membrane’s asymmetrical nature?
The two sides of a cell membrane face different environments and carry out different functions.
Which of the following statements best summarizes the differences between DNA and RNA?
DNA nucleotides contain a different sugar than RNA nucleotides
The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells?
smooth ER
Which structure is NOT part of the endomembrane system?
chloroplast
Singer and Nicolson’s fluid mosaic model of the membrane proposed that membranes_____.
consist of protein molecules embedded in a fluid bilayer of phospholipids
Which of the following includes all of the pyrimidines found in RNA and DNA?
cytosine, uracil, and thymine
Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
components of the cytoskeleton
For a protein to be an integral membrane protein, it would have to be _____.
amphipathic, with at least one hydrophobic region
Cilia and flagella bend because of _____.
a motor protein called dynein
Which of these are NOT embedded in the hydrophobic portion of the lipid bilayer at all?
peripheral proteins
Which of the following statements about the 5’ end of a polynucleotide strand of RNA is correct?
The 5’ end has a phosphate group attached to the number 5 carbon of ribose
The membranes of winter wheat are able to remain fluid when it is extremely cold by _____.
ncreasing the percentage of unsaturated phospholipids in the membrane
All of the following are part of a prokaryotic cell EXCEPT _____.
an endoplasmic reticulum
Which of the following allows water to move much faster across cell membranes?
aquaporins
