BS 161 Exam 2 Questions with Correct Answers Latest Update 2025/2026
9 | Membrane Definition - Answers Universal features of cells, they separate internal from
external and allows cells to regulate what does in and out of cells
9 | Amphipathic Definition - Answers Contain distinct polar and non polar regions example: lipids
& proteins
9 | 50% of a membranes mass - Answers Proteins
9 | Main lipid found in membranes - Answers Phospholipids
9 | Where do phospholipids form? - Answers Aqueous, neutral pH environments
9 | What is a characteristic of phospholipids in membranes related to their structure? - Answers
Hydrophobic clustering to form the membrane
9 | What type of interactions between fatty acid tails affect the fluidity of the membrane? -
Answers London Dispersion Forces (LDFs)
9 | How do cells maintain flexibility of the membrane? - Answers Regulating membrane fluidity
9 | Saturated fatty acid tails - Answers Lack double bonds, resulting in phospholipids with a
straight structure that favors tight packing
9 | Unsaturated fatty acid tails - Answers Have 1+ double bonds that introduce kinks in the
phospholipids, reducing the tightness of packing
9 | How does temperature impact membrane fluidity? - Answers An increase makes the
membrane more fluid (like oil), a decrease makes the membrane less fluid (like butter)
9 | Example of lipid cellular membranes - Answers Phospholipids & cholesterol
9 | Example of membrane proteins - Answers Transporters, receptors, and enzymes
9 | Membrane fluidity definition - Answers A characteristic of cell membranes due to membrane
lipids and membrane proteins moving around within a single layer of the bilayer membrane
9 | Amphipathic - Answers Contain polar and non-polar regions
9 | Fatty acid head (P or NP) - Answers Polar
9 | Fatty acid tail (P or NP) - Answers Non-polar
9 | What interactions are between lipid bilayers? - Answers LDFS
9 | Membrane fluidity when temperature increases - Answers More fluid
9 | Membrane fluidity when temperature decreases - Answers Less fluid
, 9 | Membrane fluidity with a short fatty acid tail - Answers More fluid
9 | Membrane fluidity with a long fatty acid tail - Answers Less fluid
9 | Membrane fluidity with an unsaturated fatty acid tail - Answers More fluid
9 | Membrane fluidity with a saturated fatty acid tail - Answers Less fluid
9 | What happens if a membrane is too fluid? - Answers Allow substances to cross too freely
and can lead to cell bursting
9 | What happens if a membrane is too stiff? - Answers They can break
9 | Why is maintaining membrane fluidity important? - Answers If membranes because too fluid
or too stiff, they no longer function as effective barriers
9 | Why are compartments beneficial to cells? - Answers They house together molecules that
relate to a specific process, they separate actions that oppose each other (synthesis and
breakdown of molecules), Internal membranes increase the space available for processes that
occur across a membrane (parts of respiration and photosynthesis)
9 | Do prokaryotes have a nucleus? - Answers No (nucleoid region)
9 | Site of transcription in prokaryotes - Answers Cytosol
9 | Site of translation in prokaryotes - Answers Cytosol
9 | Approx. size of prokaryotes in comparison to eukaryotes - Answers Smaller (1-2 micrometers)
Internal organization of prokaryotes - Answers No membrane enclosed organelles
9 | Do eukaryotes have a nucleus? - Answers Yes
9 | Site of transcription in eukaryotes - Answers Nucleus
9 | Site of translation in eukaryotes - Answers Cytosol
9 | Approx. size of eukaryotes in comparison to prokaryotes - Answers Larger (10-100
micrometers)
9 | Internal organization of eukaryotes - Answers Have membrane enclosed organelles
9 | Major function occurring in the ribosome - Answers Translation
9 | Major function occurring in the nucleus - Answers Stores the genomic DNA and is the site of
transcription
9 | Major function occurring in the endoplasmic reticulum - Answers Rough ER: Site of
9 | Membrane Definition - Answers Universal features of cells, they separate internal from
external and allows cells to regulate what does in and out of cells
9 | Amphipathic Definition - Answers Contain distinct polar and non polar regions example: lipids
& proteins
9 | 50% of a membranes mass - Answers Proteins
9 | Main lipid found in membranes - Answers Phospholipids
9 | Where do phospholipids form? - Answers Aqueous, neutral pH environments
9 | What is a characteristic of phospholipids in membranes related to their structure? - Answers
Hydrophobic clustering to form the membrane
9 | What type of interactions between fatty acid tails affect the fluidity of the membrane? -
Answers London Dispersion Forces (LDFs)
9 | How do cells maintain flexibility of the membrane? - Answers Regulating membrane fluidity
9 | Saturated fatty acid tails - Answers Lack double bonds, resulting in phospholipids with a
straight structure that favors tight packing
9 | Unsaturated fatty acid tails - Answers Have 1+ double bonds that introduce kinks in the
phospholipids, reducing the tightness of packing
9 | How does temperature impact membrane fluidity? - Answers An increase makes the
membrane more fluid (like oil), a decrease makes the membrane less fluid (like butter)
9 | Example of lipid cellular membranes - Answers Phospholipids & cholesterol
9 | Example of membrane proteins - Answers Transporters, receptors, and enzymes
9 | Membrane fluidity definition - Answers A characteristic of cell membranes due to membrane
lipids and membrane proteins moving around within a single layer of the bilayer membrane
9 | Amphipathic - Answers Contain polar and non-polar regions
9 | Fatty acid head (P or NP) - Answers Polar
9 | Fatty acid tail (P or NP) - Answers Non-polar
9 | What interactions are between lipid bilayers? - Answers LDFS
9 | Membrane fluidity when temperature increases - Answers More fluid
9 | Membrane fluidity when temperature decreases - Answers Less fluid
, 9 | Membrane fluidity with a short fatty acid tail - Answers More fluid
9 | Membrane fluidity with a long fatty acid tail - Answers Less fluid
9 | Membrane fluidity with an unsaturated fatty acid tail - Answers More fluid
9 | Membrane fluidity with a saturated fatty acid tail - Answers Less fluid
9 | What happens if a membrane is too fluid? - Answers Allow substances to cross too freely
and can lead to cell bursting
9 | What happens if a membrane is too stiff? - Answers They can break
9 | Why is maintaining membrane fluidity important? - Answers If membranes because too fluid
or too stiff, they no longer function as effective barriers
9 | Why are compartments beneficial to cells? - Answers They house together molecules that
relate to a specific process, they separate actions that oppose each other (synthesis and
breakdown of molecules), Internal membranes increase the space available for processes that
occur across a membrane (parts of respiration and photosynthesis)
9 | Do prokaryotes have a nucleus? - Answers No (nucleoid region)
9 | Site of transcription in prokaryotes - Answers Cytosol
9 | Site of translation in prokaryotes - Answers Cytosol
9 | Approx. size of prokaryotes in comparison to eukaryotes - Answers Smaller (1-2 micrometers)
Internal organization of prokaryotes - Answers No membrane enclosed organelles
9 | Do eukaryotes have a nucleus? - Answers Yes
9 | Site of transcription in eukaryotes - Answers Nucleus
9 | Site of translation in eukaryotes - Answers Cytosol
9 | Approx. size of eukaryotes in comparison to prokaryotes - Answers Larger (10-100
micrometers)
9 | Internal organization of eukaryotes - Answers Have membrane enclosed organelles
9 | Major function occurring in the ribosome - Answers Translation
9 | Major function occurring in the nucleus - Answers Stores the genomic DNA and is the site of
transcription
9 | Major function occurring in the endoplasmic reticulum - Answers Rough ER: Site of
