Mastering Biology Module 11-12 (Ch. 6+7)
A newly discovered unicellular organism isolated from acidic mine drainage is found to contain a cell wall, a plasma membrane, two flagella, and peroxisomes. Based on this information only, the organism is most likely to be ________.
a motile eukaryote
The _____ is composed of DNA and protein.
chromatin
Motor proteins provide for molecular motion in cells by interacting with which of the following cellular structures?
components of the cytoskeleton
Bending of cilia and flagella results from which of the following activities?
conformational changes in a motor protein called dynein
What cell structures best reveal evolutionary unity?
ribosomes and biological membranes
The diameter of a typical eukaryotic cell is approximately ten times the diameter of a typical prokaryote. What is the ratio of the volume of typical eukaryotic:prokaryotic cells?
1000:1
If model cells have shapes that approximate rectangular solids, which of the following dimensions will provide the cell with the greatest ratio of surface area to volume (all units are in micrometers, µm)?
101010
Which of these structures stores, modifies, and packages products?
A
Which of the following is a common trait of chloroplasts and mitochondria?
Both contain their own DNA; Mitochondria and chloroplasts contain their own DNA and ribosomes.
Choose the letter that indicates the organelle that contains most of a cell's DNA.
C
An organelle in a newly discovered cell contains thylakoids, DNA, and ribosomes. These findings suggest that this organelle is most likely similar to which of the following organelles?
Chloroplasts
Complete the descriptions of diversity related to specialized cellular modifications.
Cilia and flagella of the "9 + 2" variety are seen primarily only in motile eukaryotes. A very specialized adaptation seen in the fat-storing tissues of plant seeds is the glyoxysome, which contains enzymes that break down fatty acids, providing an energy source.
Which of these provides the cell with structural support?
D
Which molecules do not normally cross the nuclear membrane?
DNA
The primary role of _____ is to bind animal cells together.
Desmosomes
Which of these is the double membrane that encloses the nucleus?
E
True or false? Large proteins containing a nuclear localization signal (NLS) bind to the nuclear pore and enter the nucleus without any expenditure of energy.
False; Cytoplasmic proteins called importins bind to large proteins containing an NLS and mediate their transport across the nuclear membrane through an active transport (energy-requiring) process.
_____ aid in the coordination of the activities of adjacent animal cells.
Gap (communicating) junctions.
Nucleoplasmin is a nuclear protein. This protein was divided into two segments and linked to the same large cytoplasmic protein, generating two fusion proteins. After injecting these fusion proteins into a cell, one of the proteins was found in the nucleus and the other in the cytoplasm. Which of the following conclusions can be drawn from these results?
Only one of the two fusion proteins possesses a nuclear localization signal; The nuclear localization signal is only present in the fusion protein that enters the nucleus.
A small protein (molecular weight = 25,000 daltons) is injected into a cell and observed in the nucleus a short time later. What type of transport has taken place?
Passive; A 25,000-dalton protein is small enough to diffuse through nuclear pores without any expenditure of energy.
The _____ is a selective barrier, regulating the passage of material into and out of the cell.
Plasma Membrane.
Which of the following structures form cytoplasmic channels that connect adjacent plant cells through the cell walls?
Plasmodesmata.
Which statement correctly describes an endomembrane function?
Products of the ER are usually modified during their transit from the cis to the trans region of the Golgi apparatus; The cis and trans regions of the Golgi apparatus act as receiving and shipping departments. As molecules move from the cis to the trans face of the Golgi apparatus, they are usually modified.
Which of the following statements best describes some aspect of protein secretion from prokaryotic cells?
Proteins secreted by prokaryotes are likely synthesized on ribosomes bound to the cytoplasmic surface of the plasma membrane.
Which of these organelles manufactures proteins bound for secretion out of the cell?
Rough E.R.
Which of the following statements about the nuclear envelope is false?
The nuclear envelope is continuous with the Golgi apparatus.
_____ are the sites of protein synthesis.
ribosomes
Which of the following statements best explains how a modern transmission electron microscope (TEM) can achieve a resolution of about 2.0 nanometers, whereas a standard light microscope has a maximum resolution of about 200 nanometers?
The wavelengths of electron beams are much shorter than the wavelengths of visible light.
Which of these cell junctions form a barrier to the passage of materials?
Tight junctions
In experiments to test whether a protein can enter the nucleus, why would proteins be labeled with fluorescent molecules?
To make the proteins easy to see.
Movement of amoebae across a surface requires which of the following activities by components of the cytoskeleton?
assembly of actin filaments to form bulges in the plasma membrane
_____ is/are identical in structure to centrioles.
basal bodies
Which of the following choices correctly matches a tool and its proper application?
cell fractionation to study the function of specific organelles
Which of the following organelles often occupy the majority of the volume of a plant cell?
central vacuole
Which of the following correctly matches an organelle with its function?
central vacuole with storage
Which structure is common to plant and animal cells?
mitochondrion
Which of these organelles carries out cellular respiration?
mitochondrion; Mitochondria convert the chemical energy of organic molecules to chemical energy in the form of ATP.
Ribosomal subunits are manufactured by the _____.
nucleolus
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
Which of the following is present in a prokaryotic cell?
ribosome
Which of the following structures are found in plant, animal, and bacterial cells?
ribosomes
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
Where is calcium stored?
smooth endoplasmic reticulum; In addition to storing calcium, the smooth ER also plays a role in detoxification and lipid synthesis.
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
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 statements describes a primary function of integrins?
transmitting signals from the extracellular matrix to the cytoskeleton.
Which of the following molecules is required by cells to assemble cilia or flagella?
tubulin
Which statement about extracellular structures (plant cell walls and the extracellular matrix of animal cells) is correct?
Information can be transmitted from these extracellular structures to the cytoplasm; Extracellular structures provide mechanical and chemical signals that are transmitted across the plasma membrane to the interior of the cell.
Which of these are hollow rods that shape and support the cell?
Microtubules; Microtubules are rods that also play a role in organelle movement.
Which of these organelles produces H2O2 as a by-product?
Peroxisome; produce hydrogen peroxide as a by-product of their metabolic processes.
Select the correct statement describing cellular structure or function
Plant and animal cells both carry out cellular respiration, producing ATP.