Unit 2 Assessment

In mammals, an increase in the concentration of sodium in the blood triggers the release of antidiuretic hormone (ADH) from the pituitary gland. As the concentration of sodium in the blood returns to previous levels, the release of ADH from the pituitary gland is reduced. Based on the information presented, which of the following describes the most likely role of ADH in maintaining blood osmolarity?

ADH promotes an increase in the movement of water into the bloodstream.

Which of the following groups of cellular components are found in eukaryotic cells but not prokaryotic cells?

An endoplasmic reticulum, mitochondria, and a nucleus

Which of the following statements correctly describes the normal tonicity relationships between typical plant and animal cells and their respective environments?

Animal cells are generally in an isotonic solution, and plant cells are generally in a hypotonic solution.

Antidiuretic hormone (ADH) is important in maintaining homeostasis in mammals. ADH is released from the hypothalamus in response to high tissue osmolarity. In response to ADH, the collecting duct and distal tubule in the kidney become more permeable to water, which increases water reabsorption into the capillaries. The amount of hormone released is controlled by a negative feedback loop. Based on the model presented, which of the following statements expresses the proper relationship between osmolarity, ADH release, and urine production?

As tissue osmolarity rises, more ADH is released, causing less water to be excreted as urine.

Intact cells of two unknown cell types were placed into solutions with different concentrations of NaCl. Type I cells swelled and burst in the solution with the lowest concentration of NaCl. Type II cells swelled but did not burst in the solution with the lowest concentration of NaCl. Which of the following descriptions of cell type I and cell type II are most consistent with the data?

Cell 1: Animal cell surrounded by a plasma membrane only. Cell 2: Plant cell surrounded by a plasma membrane and a cell wall

Which of the following best describes an advantage that eukaryote organisms have over prokaryote organisms?

Eukaryotes have organelles that allow for compartmentalization of cellular processes, which increases the efficiency of those processes.

Liver cells manufacture glycoproteins through the modification of proteins, while adipose cells store fat. Which of the following subcellular structures is likely to be more prominent in liver cells than in adipose cells?

Golgi apparatus

A mutation that disrupts the ability of an animal cell to add polysaccharide modifications to proteins would most likely cause defects in its

Golgi apparatus and extracellular matrix.

A cell is treated with a drug that prevents the formation of new lysosomes. The cell continues to transcribe the genes that code for the hydrolytic enzymes that are normally found in lysosomes and continues to translate the mRNAs for those proteins on membrane-bound ribosomes. The hydrolytic enzymes are most likely to accumulate in which of the following cellular structures?

Golgi complex

Which of the following statements is true regarding the movement of substances across cell membranes?

Ions are unable to move through the phospholipid bilayer because the nonpolar tail regions of the phospholipids are hydrophobic.

Which of the following is true about the structure of the prokaryotic cell represented in the figure from question 11?

It has a cell wall exterior to the plasma membrane and contains ribosomes.

Why isn't the mitochondrion classified as part of the endomembrane system?

It is not derived from the endoplasmic reticulum or Golgi.

A common laboratory investigation involves putting a solution of starch and glucose into a dialysis bag and suspending the bag in a beaker of water, as shown in the figure below The investigation is aimed at understanding how molecular size affects movement through a membrane. Which of the following best represents the amount of starch, water, and glucose in the dialysis bag over the course of the investigation?

Little dash const. big dash increase, solid decrease

Which of the following processes is most likely to occur as a result of an animal cell receiving a signal to initiate apoptosis?

Lysosomes will release digestive enzymes into the cytosol.

The manner in which several different ions and molecules move through a cell membrane is shown in the diagram below. For each ion or molecule, the relative concentration on each side of the membrane is indicated. Which of the following accurately describes one of the movements taking place?

Na+ transport out of the cell requires ATP hydrolysis.

Mammalian blood contains the equivalent of 0.15 M NaCl. Seawater contains the equivalent of 0.45 M NaCl. What will happen if red blood cells are transferred to seawater?

NaCl will passively diffuse into the red blood cells.

Membrane-boundorganelleshavebeenanimportantcomponentinthe evolution of complex, multicellular organisms. Which of the following best summarizes an advantage of eukaryotic cells having internal membranes?

Organelles isolate specific reactions, increasing metabolic efficiency.

If ATP breakdown (hydrolysis) is inhibited, which of the following types of movement across cell membranes is also inhibited?

Passage of a solute against its concentration gradient

Simple cuboidal epithelial cells line the ducts of certain human exocrine glands. Various materials are transported into or out of the cells by diffusion. (The formula for the surface area of a cube is 6 S2, and the formula for the volume of a cube is S3, where S = the length of a side of the cube.) Which of the following cube-shaped cells would be most efficient in removing waste by diffusion?

Smallest: 10

The figure below represents a rough endoplasmic reticulum. Which of the following best describes the role of the structure labeled Y?

Structure Y is the location where proteins are synthesized

Intravenous (IV) solutions administered to patients are normally isotonic. Which of the following is most likely if an IV of distilled water is administered to a patient?

The cells that are exposed to hypotonic solutions will expand as water moves osmotically into the cells from the blood.

Which of the following best explains how small molecules move between adjacent cells in a plant shoot?

The molecules pass freely through plasmodesmata, which are cytoplasmic strands connecting two cells.

The diagram below represents a typical rod- shaped bacterium. Which of the following best describes a feature shown in the diagram that is unique to archaea and bacteria?

The organism does not have a nuclear membrane surrounding its genetic material.

The figure below illustrates a eukaryotic cell. Which of the following best describes how the three structures indicated by the arrows work together? (Vesicle, Golgi, Rough ER)

To synthesize and isolate proteins for secretion or for use in the cell

Which of the following is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal?

Transport of sodium ions down their electrochemical gradient facilitates the transport of glucose against its concentration gradient.

. A sample of human blood was placed in a test tube containing a physiological saline solution (0.9% sodium chloride). This type of solution is often used intravenously to quickly rehydrate patients. A drop of the blood from the test tube was placed on a slide and red blood cells (RBCs) were observed under a microscope. Three possible outcomes are diagrammed below.

View 2 because the rate of water movement into the RBCs equals the rate of water movement out of the cells

Which of the following scientific questions is most relevant to the model represented in the figure below?

Which molecular substance is actively transported across the plasma membrane?

The nuclear lamina is a netlike array of filaments on the inner side of the nuclear membrane. If a method were found that could cause the lamina to fall into disarray, what would you expect to be the most likely immediate consequence?

a change in the shape of the nucleus

An integral membrane protein would have to be

amphipathic, with at least one hydrophobic region

Which of the following is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold?

by increasing the percentage of unsaturated phospholipids in the membrane

The fluid mosaic model of the membrane proposed that membranes

consist of protein molecules embedded in a fluid bilayer of phospholipids.

A primary function of cholesterol in the plasma membranes of some animals is to

enable the membrane to stay fluid more easily when the temperature drops.

Which of the following may be found in eukaryotic cells, but not in bacteria?

endoplasmic reticulum

Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells?

gap junctions

The solutions in the arms of a U-tube (Figure 5.3) are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same. Refer to the figure to answer the following questions.

is hypotonic to side B.

The solutions in the two arms of this U-tube (Figure 5.2) are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half-filled with a solution of 2 M sucrose and 1 M glucose. Side B is half-filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels are equal. Refer to the figure to answer the following question(s). Initially, in terms of tonicity in the figure, the solution in side A with respect to that insideB is

isotonic.

Water passes quickly through cell membranes because

it moves through aquaporin channel proteins.

One advantage of light microscopy over transmission electron microscopy is that

light microscopy allows one to view dynamic processes in living cells.

The sodium-potassium pump generates the following concentration gradients across the plasma membrane:

low [Na+] and high [K+] inside the cell and high [Na+] and low [K+] outside.

A bacterium engulfed by a white blood cell through phagocytosis will be digested by enzymes contained in

lysosomes.

A primary function of polysaccharides attached to glycoproteins and glycolipids of animal cell membranes is to

mediate cell-to-cell recognition.

What is the voltage across a membrane called?

membrane potential

What types of proteins are synthesized somewhere other than the rough ER?

mitochondrial proteins

Which of the following membrane activities requires energy from ATP hydrolysis?

movement of sodium ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

Which of the following tend to lack hydrophobic regions on their surface?

peripheral proteins

The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that

plant cells contain a large vacuole that reduces the volume of the cytoplasm.

A cell with an abundance of free ribosomes is most likely

producing primarily cytoplasmic proteins.

Which of the following statements correctly describes a function of the Golgi apparatus?

protein modification and sorting

Which structure is the site of the synthesis of proteins destined for export from the cell?

rough ER

Which of the following correctly describes the pathway taken by a protein destined for secretion from an animal cell?

rough ER → transport vesicle → Golgi → transport vesicle → plasma membrane

What kinds of molecules pass through a cell membrane most easily?

small hydrophobic

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

Submerging a plant cell in distilled water will result in

the cell becoming turgid.

Tay-Sachs disease is a human genetic abnormality that results in cells accumulating very large, complex, undigested lipids. Which cellular organelle must be defective in this condition?

the lysosome

When biologists wish to study the internal ultrastructure of cells, they can achieve the finest resolution by using a

transmission electronic microscope.