WorksheetsIB Biology 1.3
Total questions: 15
Worksheet time: 8mins
What special property of phospholipid molecules explains their ability to spontaneously assemble into a lipid bilayer?
A. They are hydrophobic.
B. They are amphipathic.
C. They are saturated.
D. They are hydrophilic.
Which statement applies to cholesterol?
A. It is hydrophobic and found on the outside of the phospholipid bilayer.
B. It is hydrophilic and found inside the phospholipid bilayer.
C. It impacts membrane fluidity.
D. It is transported in association with glucose in the blood.
The Davson–Danielli model of membrane structure proposed that membranes were composed of a phospholipid bilayer that lies between two layers of globular proteins, as shown in this diagram.
The Davson–Danielli model of membrane structure proposed that membranes were composed of a phospholipid bilayer that lies between two layers of globular proteins, as shown in this diagram.
A. An electron micrograph that showed two dark lines with a lighter band in between
B. Freeze-fracture electron microscopy
C. Evidence that all membranes are identical
D. The hydrophobic regions of protein would be in contact with water.
A diagram of a membrane
A
B
C
D
A diagram of a membrane
In the diagram, which structure is an intrinsic or integral protein?
A.
B.
C.
D.
The cell membrane model proposed by Davson–Danielli was a phospholipid bilayer sandwiched between two layers of globular protein. Which evidence led to the acceptance of the Singer–Nicolson model?
A. The orientation of the hydrophilic phospholipid heads towards the proteins
B. The formation of a hydrophobic region on the surface of the membrane
C. The placement of integral and peripheral proteins in the membrane
D. The interactions due to amphipathic properties of phospholipids
What are the parts of the cell membrane indicated in the diagram?
A.
B.
C.
D.
A number of different proteins are involved in nerve function. Which of the following does not require a membrane protein?
A. Active transport of sodium
B. Diffusion of K+ into the cell
C. Diffusion of the neurotransmitter across the synapse
D. Binding of the neurotransmitter to the post-synaptic membrane
What is the approximate thickness of the plasma membrane of a cell?
A. 10 nm
B. 50 nm
C. 10 µm
D. 50 µm
Which process is possible due to the fluidity of cell membranes?
A. Endocytosis
B. Osmosis
C. ATP production
D. Cell recognition
The diagram below shows a plasma membrane. What is molecule X?
A. Cholesterol
B. Peripheral protein
C. Glycoprotein
D. Polar amino acid
What is a role of cholesterol in animal cells?
A. It increases body fat.
B. It controls membrane fluidity.
C. It lines the inner wall of capillaries.
D. It is a constituent of bile.
The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive system. The graph shows the percentage of samples in which this bacterium showed resistance to six antibiotics over a period of ten years.
What is a possible explanation for the total percentage resistance being larger than 100% in 2010?
A. People do not take the antibiotics as prescribed.
B. More people have been sampled in that year.
C. There was an epidemic of Neisseria gonorrhoeae in that year.
D. Some bacteria are resistant to more than one antibiotic.
Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is based on DNA sequences and the cladogram on the right is based on comparing protein sequences.
What is the reason that cladograms based on DNA sequences are more reliable predictors of the phylogenetic relationship of species than cladograms based on protein sequences?
A. Amino acids are not as chemically stable as DNA nucleotides.
B. DNA mutates but amino acids do not.
C. Several different triplets of bases can code for the same amino acid
D. There are 20 different amino acids but only 4 nucleotides
What feature of cell membranes allows endocytosis to occur?
A. Fluidity of phospholipid bilayer
B. Presence of protein pumps
C. Presence of carrier proteins
D. Glycoprotein binding sites
