Unit 2 Bio Exam (Chapters 6, 7, 25, 36)
Because the C-H bonds in the fatty acid tails are relatively nonpolar, the phospholipid tails are ______________, which means they are excluded from water.
hydrophobic
above, greater than
hyper-
below, less than
hypo-
Is the solution outside the cell isotonic, hypotonic, or hypertonic?
hypotonic
Tay-Sachs disease is a human genetic disorder that results in cellular accumulation of very large, complex, undigested lipids. Which of the following organelles is most likely defective in Tay-Sachs disease?
the lysosome
Which of the following membrane activities requires energy from ATP hydrolysis?
movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid
All proteins are synthesized by ribosomes in the cell. Some ribosomes float freely in the cytosol, while others are bound to the surface of the endoplasmic reticulum. Most proteins made by free ribosomes function in the cytosol. Proteins made by bound ribosomes either function within the endomembrane system or pass through it and are secreted from the cell. Which of the following proteins are synthesized by bound ribosomes?
- ER protein - insulin - lysosomal enzyme
lysosomes
- macromolecule digestion - autophagy
Golgi apparatus
- protein modification and sorting - cisternal maturation
Which line in the graph represents the bag with the highest initial concentration of sucrose?
A
Which of the following statements best describes a characteristic feature of a carrier protein in a plasma membrane?
It exhibits specificity for a particular type of molecule.
Which of the following statements best describes the function of the nuclear pore complex found in eukaryotic cells?
It regulates the movement of proteins and RNAs into and out of the nucleus.
water
aqu- (or aqua-)
two
bi-
green
chloro-
Phospholipids vary in the small molecules attached to the phosphate group. The phospholipid shown in the figure has a ___________ ____ attached to phosphate.
choline group
color
chrom-
The movement of glucose into a cell against its concentration gradient is most likely to be accomplished by which of the following?
cotransport of the glucose with a proton or sodium ion that was pumped across the membrane using the energy of ATP hydrolysis
In some cells, there are many different ion electrochemical gradients across the plasma membrane even though there are usually only one or two types of proton pumps present in the membrane. The gradients of the other ions are most likely established by which of the following?
cotransport proteins
cell
-cyte (or cyto-)
little, small
-elle
leaf
-phyll
formed substance
-plasm
body
-some (or soma-)
Which unknown solution contains the highest concentration of sucrose?
1
Which of these can RAPIDLY pass directly through the phospholipids of the plasma membrane, without the help of a transport protein?
A only
Five dialysis bags, constructed of a type of membrane that is permeable to water and impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were weighed, and the percent change in mass of each bag was graphed. Which line in the graph represents the bag that contained a solution isotonic to the 0.6 M solution at the beginning of the experiment?
C
Which component in the figure above is hydrophilic?
D
Which of the following statements correctly describes some aspect of exocytosis or endocytosis?
Exocytosis and endocytosis change the surface area of the plasma membrane.
A small surface area to volume ratio is desirable for the cell to transport enough nutrients and waste across the plasma membrane to meet its metabolic needs
False
As a cell increases in size, the surface area increases proportionately more than the volume.
False
Organism A is a single-celled organism with a surface area-to-volume ratio of 4.5. Organism B is a multicellular organism with a surface area-to-volume ratio of 3.2. Which organism's surface area to volume ratio will better support its cellular interior(s), and why?
Organism A because it has the higher surface area to volume ratio.
Select the correct statement about osmosis.
Osmosis is the diffusion of water molecules across a selectively permeable membrane.
From the data given, which statement below most accurately describes something that has occurred in response to a particular unknown solution?
Osmosis of water molecules from unknown solution 2 likely caused the increase in mass observed.
Which of the following statements best describes a characteristic of biological membranes?
Phospholipids move laterally within the plane of the membrane.
Which of the following statements provides the best support for the hypothesis that the mitochondria and plastids of modern eukaryotic cells were originally independent, free-living bacteria?
The DNA of mitochondria and plastids is circular and the ribosomes of mitochondria and plastids are more similar to that of bacterial ribosomes than to the ribosomes in the cytoplasm of the eukaryotic cell.
Will the artificial cell become more flaccid, more turgid, or stay the same?
The artificial cell will become more turgid.
Identify the correct statement about differences between rough and smooth endoplasmic reticulum (ER).
The outer surface of smooth ER lacks ribosomes, whereas the outer surface of rough ER has ribosomes.
Which of the following statements about osmosis is correct?
The presence of aquaporins (proteins that form water channels in the membrane) speeds up the process of osmosis.
If isolated plant cells with a water potential averaging -0.5 MPa are placed into a solution with a water potential of -0.3 MPa which of the following would be the most likely outcome?
The pressure potential of the cells would increase.
Which of the following statements best describes characteristic activities of a sodium-potassium pump?
The pump moves three sodium ions out of a cell and two potassium ions into a cell using energy from ATP hydrolysis.
Which factors affect the rate of osmotic movement of water?
The rate of osmosis increases with increasing differences in solute concentrations between two solutions separated by a selectively permeable membrane.
Which of the following statements about a typical plasma membrane is correct?
The two sides of the plasma membrane have different lipid and protein composition.
Eventually, will the two solutions have the same or different solute concentrations?
The two solutions will have the same solute concentration.
A cell's growth is limited by its surface area to volume ratio
True
Multicellularity in large organisms results in more, smaller cells and thus a higher surface area to volume ratio
True
The surface area of a cell is determined by the surface area of the plasma membrane, the selective boundary through which materials enter and exit the cell
True
The force driving simple diffusion is ________, while the energy source for active transport is ________.
a concentration gradient; ATP hydrolysis
Which of the following factors would tend to increase membrane fluidity?
a greater proportion of unsaturated phospholipids
without, lack of, not
a- (or an-)
Active and passive transport of solutes across a membrane typically differ in which of the following ways?
active transport always involves the utilization of cellular energy, whereas passive transport does not require cellular energy
According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly
embedded in a lipid bilayer.
inside, inner
endo-
true, good
eu-
out of
ex-
A phospholipid also has two "tails" made up of two ________ _____ molecules, which consist of a carboxyl group with a long hydrocarbon chain attached.
fatty acid
Identify Structure A.
glycoprotein
Because the phosphate group and its attachments are either charged or polar, the phospholipid head is _____________, which means it has an affinity for water.
hydrophilic
between
inter-
Many cell organelles, most notably the nucleus, are anchored by ________________ __________ which are assembled from a diverse class of proteins.
intermediate filaments
The only cytoskeletal fibers not associated with intracellular movement or whole cell locomotion are the ______________ _________.
intermediate filaments
Eukaryotic only
lysosome, mitochondria, nucleolus
Asbestos is a material that was extensively used in construction for decades. One risk from working in a building that contains asbestos is the development of asbestosis caused by the inhalation of asbestos fibers. Cells will take up asbestos by phagocytosis, but are not able to degrade it. Toxicity most likely results from accumulation of asbestos in which of the following organelles?
lysosomes
Which of the following organelles plays a primary role in the digestion of bacteria engulfed by white blood cells?
lysosomes
Disruption of nuclear pore complexes in a eukaryotic cell will most likely interfere with the transport of which of the following molecules out of the nucleus?
mRNA
Smooth ER
makes lipids so: - lipid synthesis - calcium ion storage - poison detoxification
small
micro-
During muscle contractions, myosin motor proteins move across tracks of ______________.
microfilaments
The extension of pseudopodia in amoeba is due to the regulated assembly and destruction of _______________.
microfilaments
Centrosomes are sites where protein dimers assemble into ______________.
microtubules
In eukaryotic flagella, the fibers that slide past one another due to the activity of dynein proteins are
microtubules
thread
mito-
Prokaryotic only
nucleoid
In receptor-mediated endocytosis, membrane receptors bind to molecules outside of the cell. Immediately following endocytosis where will the membrane receptors be located?
on the inside surface of the vesicle
Which of the following types of molecules are most likely to be excluded from the hydrophobic portion of the phospholipid bilayer?
peripheral membrane proteins
eat
phago-
A phospholipid has a "head" made up of a glycerol molecule attached to a single ____________ ______, which is attached to another small molecule.
phosphate group
Identify Structure D.
phospholipid bilayer of membrane
Which of the following lists most likely represents the correct sequence, from earliest to most recent, in the origin of cell organelles and cellular organization?
photosynthetic prokaryotes, mitochondria, chloroplasts, multicellular eukaryotes
Which of the following statements best describes the difference between pinocytosis and receptor-mediated endocytosis?
pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity
A cell with a predominance of rough endoplasmic reticulum is most likely involved in which of the following processes?
producing large quantities of proteins for secretion
Rough ER
protein synthesis
The pathway of secretory proteins
protein synthesis -> endoplasmic reticulum -> cis Golgi cisternae -> medial Golgi cisternae -> trans Golgi cisternae -> plasma membrane -> extracellular space
Examination of a cell by transmission electron microscopy reveals a high density of ribosomes in the cytoplasm. This observation suggests that the cell is actively producing large amounts of which of the following molecules?
proteins
Which of the following would be least likely to affect osmosis in plants?
receptor proteins in the membrane
Both Prokaryotic and Eukaryotic
ribosomes, plasma membrane, flagella
A newly synthesized protein destined for secretion from a eukaryotic cell will generally follow which of the pathways listed below?
rough ER → Golgi → transport vesicle → plasma membrane
Which of the following types of molecules are least likely to diffuse through the phospholipid bilayer of a cell membrane?
small ions
The liver is involved in detoxification of many poisons and drugs. Which of the following structures is abundant in liver cells and primarily responsible for detoxification processes?
smooth endoplasmic reticulum
What is the function of Structure E?
stabilization of the phospholipids
same
sym-
A cell with a predominance of smooth endoplasmic reticulum is most likely specialized to carry out which of the following processes?
synthesis of large quantities of lipids
A new drug designed for the treatment of lung cancer must specifically enter the cytoplasm of lung cells while not entering the cells of other tissues. Which of the following characteristics would likely enhance the specificity of this drug?
the similarity of the drug molecule to other molecules normally transported lung cells
The permeability of a biological membrane to a specific polar solute may depend on which of the following?
the types of transport proteins in the membrane
When an animal cell is placed in a hypotonic solution and water enters the cell via osmosis, the volume of the cell increases until it bursts. Which of the following explains why this does not happen to plant cells?
they have cell walls, which provide pressure to counteract the pressure of the incoming water
What is the function of proton pumps localized in the plant plasma membrane?
to create a membrane potential
across
trans-
Structure A in the figure is a(n) _____.
transport protein
Which of the following best describes the structure of a biological membrane?
two layers of phospholipids, with proteins either crossing the layers or on the surface of the layers
Which of the following terms describes the physical property that predicts the direction of water flow in plants?
water potential
