Biology Test 1 Chapter 4

Some antibiotics used to treat bacterial infections kill the bacteria by chemically punching holes in the cell wall of the bacteria, by preventing the bacteria from replicating their DNA, or by many other actions that ultimately cause cell death. Why do these antibiotics not work to kill viruses and cure people of viral infections? a. Antibiotics cannot kill a virus because viruses are not living cells with cell walls to puncture, nor do they have their own organelles to replicate DNA. b. Viruses are just too virulent to be killed by those antibiotics. c. Viruses are too quick for the antibiotics to work. d. Viruses mutate at a rate faster than the rate at which antibiotics can work to kill them.

a. Antibiotics cannot kill a virus because viruses are not living cells with cell walls to puncture, nor do they have their own organelles to replicate DNA.

Compare and contrast the nuclear envelope and the plasma membrane. a. The nuclear envelope consists of two concentric phospholipid bilayers while the plasma membrane is only one phospholipid bilayer. Both membranes are selectively permeable and have pores. b. The nuclear envelope consists of two concentric phospholipid bilayers while the plasma membrane is only one phospholipid bilayer. Neither membrane is selectively permeable or has pores. c. Both membranes consist of two concentric phospholipid bilayers, are selectively permeable, and have pores. d. Both membranes consist of two concentric phospholipid bilayers and neither is selectively permeable or has pores.

a. The nuclear envelope consists of two concentric phospholipid bilayers while the plasma membrane is only one phospholipid bilayer. Both membranes are selectively permeable and have pores.

You buy a bunch of small, round, red radishes at the grocery store; they are on sale because they have been sitting in the produce aisle for a while. When you get home you remove the stems and clean them. With the first bite, you notice their texture is not as crisp and crunchy as you like. Your friend says you should refrigerate them in a bowl of water overnight. The next day the radishes are crisp and crunchy again. What is the most likely explanation of why they became crunchy again after soaking in water? a. The radish cells were hypertonic to the water in which they were soaking. So, the water moved by osmosis across the plasma membranes into the radish cells increasing the turgor pressure inside of the cells and making them crunchier. b. The radish cells were hypotonic to the water in which they were soaking. So, the water osmosed across the plasma membranes out of the radish cells decreasing the turgor pressure inside of the cells and making them crunchier. c. The radish cells were hypertonic to the water in which they were soaking. So, the water osmosed across the plasma membranes into the radish cells decreasing the turgor pressure inside of the cells. d. The radish cells were hypotonic to the water in which they were soaking. So, the water osmosed across the plasma membranes into the radish cells decreasing the turgor pressure inside of the cells.

a. The radish cells were hypertonic to the water in which they were soaking. So, the water moved by osmosis across the plasma membranes into the radish cells increasing the turgor pressure inside of the cells and making them crunchier.

Examine the figure below. If each sugar molecule represents a percentage point of sugar dissolved in the solution, what change would you expect to see in the solution level over time and why? a. The solution level on the left side of the figure would rise while the solution level on the right side of the figure would decrease. This is because the solution on the left side of the figure is hypertonic while the solution on the right side of the figure is hypotonic. b. The solution level on the left side of the figure would decrease while the solution level on the right side of the figure would rise. This is because the solution on the left side of the figure is hypertonic while the solution on the right side of the figure is hypotonic. c. The solution level on the left side of the figure would decrease while the solution level on the right side of the figure would rise. This is because the solution on the left side of the figure is hypotonic while the solution on the right side of the figure is hypertonic. d. There will be no net movement of water because the solutions are isotonic. ** see figure

a. The solution level on the left side of the figure would rise while the solution level on the right side of the figure would decrease. This is because the solution on the left side of the figure is hypertonic while the solution on the right side of the figure is hypotonic.

Which of the following types of organisms are commonly single-celled (unicellular)? a. bacteria, some fungi (yeast), and many protozoans b. many fungi, some protozoans, and plants c. plants and animals d. many fungi, plants, and animals

a. bacteria, some fungi (yeast), and many protozoans

The smooth endoplasmic reticulum a. is the site where lipids destined for other cellular compartments are manufactured. b. produces the energy needed to run chemical reactions in the cell. c. converts sunlight into chemical energy. d. stores water, nutrients, and enzymes.

a. is the site where lipids destined for other cellular compartments are manufactured.

Your muscle cells need large amounts of ATP to function in the movement of your body. Which of the following organelles would you expect to be especially abundant in muscle cells? a. mitochondria c. smooth endoplasmic reticulum b. ribosomes d. lysosomes

a. mitochondria

During the process of ________, water diffuses across a semipermeable membrane from an area where water is more concentrated to an area where water is less concentrated (it moves along the water concentration gradient). a. osmosis c. facilitated diffusion b. simple diffusion d. pinocytosis

a. osmosis

Which of the following would be likely to move through a plasma membrane by simple diffusion? a. water (H2O), carbon dioxide (CO2), oxygen (O2) b. polysaccharides, large protein molecules, low-density lipoprotein particles c. bacteria and yeast d. sodium ions (Na+), hydrogen ions (H+), sugars, and amino acids

a. water (H2O), carbon dioxide (CO2), oxygen (O2)

You are a microbiologist working with a species of bacteria that can perform photosynthesis. You know that the enzymes needed to perform photosynthesis in plant cells are closely associated with the membranes in chloroplasts. Where in the bacteria would you expect to find the enzymes needed to perform photosynthesis? a. I would expect to find the photosynthetic enzymes in the chloroplasts of the bacteria. b. I would expect to find the photosynthetic enzymes associated with the plasma membrane of the bacteria. c. I would expect to find the photosynthetic enzymes associated with the mitochondria of the bacteria. d. I would expect to find the photosynthetic enzymes associated with the ER of the bacteria.

b. I would expect to find the photosynthetic enzymes associated with the plasma membrane of the bacteria.

An experiment mixed together oil (lipids), organophosphate-containing detergent in water, and copper ions to act as a catalyst for a chemical reaction. Membranes budded off of the oil in this mixture. Which of the following is a reasonable and possible explanation of the experimental results? a. The chemical reaction caused the organophosphates from the detergent to chemically combine with lipids from the oil to form phospholipids. The hydrophilic tails lined up towards each other with their hydrophobic heads pointing out towards the water; this configuration formed a phospholipid bilayer that pulled into a liposome. b. The chemical reaction caused the organophosphates from the detergent to chemically combine with lipids from the oil to form phospholipids with hydrophilic heads and hydrophobic tails. The hydrophobic tails lined up towards each other with their hydrophilic heads pointing out towards the water; this configuration formed a phospholipid bilayer that pulled into a spherical liposome. c. The copper ions permanently, chemically combined with the lipids to form phospholipids. The hydrophilic tails lined up towards each other with their hydrophobic heads pointing out towards the water; this configuration formed a phospholipid bilayer that pulled into a liposome. d. The copper ions permanently, chemically combined with the lipids and phosphates to form phospholipids. The hydrophilic tails lined up towards each other with their hydrophobic heads pointing out towards the water; this configuration formed a phospholipid bilayer that pulled into a liposome.

b. The chemical reaction caused the organophosphates from the detergent to chemically combine with lipids from the oil to form phospholipids with hydrophilic heads and hydrophobic tails. The hydrophobic tails lined up towards each other with their hydrophilic heads pointing out towards the water; this configuration formed a phospholipid bilayer that pulled into a spherical liposome.

If the concentration of sugar molecules in water on side "A" of a selectively permeable membrane is 5 percent, and the concentration of sugar molecules in water on side "B" of a selectively permeable membrane is 15 percent, which way will the water move and why? a. The water will mostly move from side "B" to side "A" because the water concentration is higher on side "B." b. The water will mostly move from side "A" to side "B" because the water concentration is higher on side "A." c. The water will mostly move from side "A" to side "B" because the water concentration is higher on side "B." d. The water will not move at all because the water concentrations are isotonic.

b. The water will mostly move from side "A" to side "B" because the water concentration is higher on side "A."

Which of the following statements is true of chloroplasts? a. They produce proteins used by other parts of the cell. b. They capture energy from sunlight. c. They give an animal cell its shape. d. They contain an entire copy of a cell's genetic material.

b. They capture energy from sunlight.

Which of the following would be the best analogy for the function of the Golgi apparatus? a. the machine that assembles a product b. a worker in a factory who places labels on products and then packs them into a shipping box c. the garbage truck that hauls away the wastes produced as a product is made d. the blueprints for making the product

b. a worker in a factory who places labels on products and then packs them into a shipping box

Phospholipids are large organic molecules with a ________, polar phosphate head connected to ________, nonpolar fatty acid tails. How do these molecules arrange themselves to form a mostly impermeable barrier between a liposome and its environment? a. hydrophilic; hydrophobic; They line up hydrophilic head to hydrophilic head with the tails all facing outward from the center line of the membrane. b. hydrophilic; hydrophobic; They line up hydrophobic tails facing each other at the center line of the membrane with the hydrophilic heads facing outward, away from the center line of the membrane. c. hydrophobic; hydrophilic; They line up hydrophobic tails facing each other with the hydrophilic heads facing outward, away from the center line of the membrane. d. hydrophobic; hydrophilic; They line up hydrophilic head to hydrophilic head with the tails all facing outward from the center line of the membrane.

b. hydrophilic; hydrophobic; They line up hydrophobic tails facing each other at the center line of the membrane with the hydrophilic heads facing outward, away from the center line of the membrane.

The boundary that surrounds the contents of the nucleus is the a. plasma membrane. c. nuclear pore. b. nuclear envelope. d. cytosol.

b. nuclear envelope.

Adenine (A), thymine (T), guanine (G), and cytosine (C) are the ________ building blocks for DNA; they are organized in different combinations to code for all of the proteins needed to accomplish everything the cell does. a. carbohydrate c. protein b. nucleotide d. lipid

b. nucleotide

Cells naturally, without using energy, respond to changes in water concentration through the process of a. facilitated diffusion. c. phagocytosis. b. osmosis. d. active transport.

b. osmosis.

Ribosomes are very small non-membranous organelles that can either exist freely in the cytoplasm or be embedded in the endoplasmic reticulum of a cell; they are associated with the synthesis of a. lipids. c. nucleic acids. b. proteins. d. carbohydrates.

b. proteins.

The plasma membrane of some white blood cells contain ________ that bind with proteins of cells such as bacteria that have invaded the human body. These special proteins tell the white blood cells those bacterial cells do not belong to that particular human and to phagocytize (eat) them. a. channel proteins c. diffusion proteins b. receptor proteins d. carrier proteins

b. receptor proteins

Which of the following would be likely to require facilitated diffusion to move across the plasma membrane? a. water (H2O) b. sodium ions (Na+), hydrogen ions (H+), sugars, and amino acids c. oxygen (O2) d. carbon dioxide (CO2)

b. sodium ions (Na+), hydrogen ions (H+), sugars, and amino acids

The Golgi apparatus a. is the place where a cell's genetic material is stored. b. sorts proteins and lipids and sends them to their final destination. c. captures energy from sunlight and sends it to the mitochondria. d. creates energy by converting ribosomes to proteins.

b. sorts proteins and lipids and sends them to their final destination.

A screen door allows breezes to enter and aromas to exit but keeps out insects. Its function most resembles a. the cytosol. c. the ER lumen. b. the plasma membrane. d. a ribosome.

b. the plasma membrane.

Prokaryotes and eukaryotes are primarily distinguished by the absence or presence of internal membrane-enclosed organelles. Are prokaryotic cells at an evolutionary disadvantage because they lack organelles? a. Yes; without organelles, prokaryotic cells cannot photosynthesize or respire. b. Yes; without organelles, prokaryotes are unable to bring together the reactants needed for biological reactions. c. No; although prokaryotic cells are comparatively less efficient than eukaryotic cells, they are still able to carry out the processes necessary for survival and reproduction. d. No; eukaryotic organelles are expelled each time the cell divides.

c. No; although prokaryotic cells are comparatively less efficient than eukaryotic cells, they are still able to carry out the processes necessary for survival and reproduction.

Dialysis tubing is a selectively permeable membrane that can be filled with a solution to simulate a cell. A piece of dialysis tubing has been filled with a cloudy white solution of 5 percent starch, 5 percent egg albumin (protein), and 5 percent glucose (a small sugar) dissolved in water to simulate a cell. This cell is weighed and then placed in a beaker of 3 percent iodine dissolved in water. When iodine and starch are mixed together, they form a bluish-black compound that is easily seen. After soaking in the yellow iodine-water solution for one hour, the cell is once again weighed. You also notice that the solution inside of the cell is now a dark blue color while the solution in the beaker is still a light yellow color from the iodine. What do you expect to happen to the weight of the cell over time and what can you deduce from the color change? a. The cell should lose weight over time because it is hypotonic to the beaker environment and water will enter the cell through osmosis. The color change indicates that the iodine molecules were small enough to diffuse across the membrane and react with the starch inside the cell. b. The cell should lose weight over time because it is hypertonic to the beaker environment and water will leave the cell through osmosis. There is nothing that the color change can tell us. c. The cell should gain weight over time because it is hypertonic to the beaker environment and water will enter the cell through osmosis. The color change indicates that the iodine molecules were small enough to diffuse across the membrane and react with the starch inside the cell. No color change in the beaker tells us that the starch was too large to cross the membrane from the cell and into the beaker. d. The cell should gain weight over time because it is isotonic to the beaker environment and water will be drawn into the cell because of the albumin. The color change does not really tell us anything about the experiment.

c. The cell should gain weight over time because it is hypertonic to the beaker environment and water will enter the cell through osmosis. The color change indicates that the iodine molecules were small enough to diffuse across the membrane and react with the starch inside the cell. No color change in the beaker tells us that the starch was too large to cross the membrane from the cell and into the beaker.

You are in lab attempting to prepare a slide of cow blood for observation in a wet mount. You place a small drop of the blood on a slide, add a drop of strong saline (salt) solution, and then cover all of it with a coverslip. After returning to your desk, you observe the slide with your microscope and notice that all of the red blood cells (RBCs) do not look like the nice round donut shaped cells in your lab manual. Instead, the RBCs look very shriveled up. Your lab partner has also made a slide, but the RBCs on their slide do look like the ones in the lab manual; your lab partner used a more dilute solution of saline but the same vial of blood. What is the most plausible explanation for the appearance of the blood cells on your slide? a. The saline you used was hypotonic to the RBCs; this resulted in water osmosing through the RBC plasma membrane mostly into the cells. b. The saline you used was isotonic to the RBCs; this resulted in water osmosing through the RBC plasma membrane into and out of the cells at an equal rate. c. The saline you used was hypertonic to the RBCs; this resulted in water osmosing through the RBC plasma membrane mostly out of the cell. d. The RBCs were hypertonic to the saline; this resulted in water osmosing through the RBC plasma membrane mostly into the cells.

c. The saline you used was hypertonic to the RBCs; this resulted in water osmosing through the RBC plasma membrane mostly out of the cell.

Why would hydrophilic substances such as sodium ions (Na+), hydrogen ions (H+), sugars, and amino acids be unable to simply diffuse across a plasma membrane? a. They readily mix with the hydrophobic tails forming the core of the phospholipid bilayer. b. They are repelled by the hydrophilic heads of the phospholipids that form the phospholipid bilayer. c. They do not readily mix with the hydrophobic tails forming the core of the phospholipid bilayer; therefore, they must move across by facilitated diffusion. d. They do not readily mix with the hydrophobic tails forming the core of the phospholipid bilayer; therefore, the only way they can move into the cell is by endocytosis.

c. They do not readily mix with the hydrophobic tails forming the core of the phospholipid bilayer; therefore, they must move across by facilitated diffusion.

Why do scientists repeat their experiments over and over again? a. They never get it right the first time. b. They can never be sure what procedural steps they followed the first few times. c. They must make sure the results were not an accident and that they are repeatable. d. They simply have extra time and resources that must be used.

c. They must make sure the results were not an accident and that they are repeatable.

Using the compound light microscope in the lab room, you observe a wet mount slide preparation. You observe layers of cells that have a definite, rigid, rectangular shape; there appears to be a nucleus in all of the cells and there are many oval-shaped green structures that seem to be moving around inside of the cells in an orderly fashion. What general cell type are you most likely observing? a. prokaryotic and plant c. eukaryotic and plant b. prokaryotic and animal d. eukaryotic and animal

c. eukaryotic and plant

A solid waste (garbage) transfer facility that sorts and breaks down garbage into recyclables and waste to be thrown away in the landfill would be a suitable analogy for which cellular organelle? a. smooth ER c. lysosome b. rough ER d. nucleus

c. lysosome

A protein molecule, transferrin, embedded in the plasma membrane recognizes iron molecules and causes the plasma membrane to fold in around the iron and take it into the cell. This is an example of a. osmosis. c. receptor-mediated endocytosis. b. diffusion. d. pinocytosis.

c. receptor-mediated endocytosis.

You are a scientist observing a membrane through which water and some small hydrophobic molecules can freely pass along a concentration gradient from high to low. However, some sugar molecules are too large to pass through the membrane either way without the assistance of passive transport proteins. Additionally, small Na ions and some proteins can pass through the membrane against the concentration gradient, but both require the assistance of active transport proteins. What general type of membrane are you observing? a. impermeable c. semipermeable b. impenetrable d. completely permeable

c. semipermeable

Which of the following statements most accurately describes a selectively permeable membrane? a. Solutes are never able to cross the membrane. b. Large molecules are always excluded from crossing the membrane. c. Substances can only pass through the membrane with the help of either active or passive transport proteins. d. Certain solutes move freely across the membrane by simple diffusion while others must be helped across by active or passive transport proteins; some substances are completely excluded from crossing the membrane.

d. Certain solutes move freely across the membrane by simple diffusion while others must be helped across by active or passive transport proteins; some substances are completely excluded from crossing the membrane.

If a bottle of perfume were spilled in the corner of a large lecture hall, the students sitting near that corner of the room would very quickly smell the perfume. Over time, the students sitting in the far corner of the room would smell the perfume. What phenomenon has occurred to the perfume molecules that have entered the air? a. osmosis c. active transport b. facilitated diffusion d. simple diffusion

d. simple diffusion

Which of the following is/are part of accepted cell theory? a. Every living organism is composed of one or more cells, and all living cells have membrane-enclosed organelles. b. All living cells arise from preexisting cells, and all living cells have membrane-enclosed organelles. c. All living cells have membrane-enclosed organelles. d. Every living organism is composed of one or more cells, and all living cells arise from preexisting cells.

d. Every living organism is composed of one or more cells, and all living cells arise from preexisting cells.

From what substance do liposomes spontaneously form and why are they important? a. Liposomes spontaneously form from DNA and proteins and provide a rigid structure to support the cell. b. They are formed from phospholipid monolayers. These phospholipid monolayers provide a stable barrier between the internal and external environments. c. Liposomes were the first rigid cell walls providing support for the living cell and a barrier between the external and internal environments. d. Liposomes form from phospholipid bilayers and provide a barrier between an external environment and an internal environment; this creates an internal environment where specific chemical reactions needed to establish a living cell can occur separately from the external environment.

d. Liposomes form from phospholipid bilayers and provide a barrier between an external environment and an internal environment; this creates an internal environment where specific chemical reactions needed to establish a living cell can occur separately from the external environment.

Examine the figure below. If each sugar molecule represents a percentage point of sugar dissolved in the solution, what change would you expect to see in the solution level over time and why? a. The solution level on the left side of the figure would rise while the solution level on the right side of the figure would decrease. This is because the solution on the left side of the figure is hypertonic while the solution on the right side of the figure is hypotonic. b. The solution level on the left side of the figure would decrease while the solution level on the right side of the figure would rise. This is because the solution on the left side of the figure is hypertonic while the solution on the right side of the figure is hypotonic. c. The solution level on the left side of the figure would decrease while the solution level on the right side of the figure would rise. This is because the solution on the left side of the figure is hypotonic while the solution on the right side of the figure is hypertonic. d. There will be no net movement of water because the solutions are isotonic. **see figure

d. There will be no net movement of water because the solutions are isotonic.

Which of the following help increase the selective permeability of a phospholipid bilayer membrane? a. transport proteins b. channel proteins c. passive carrier proteins d. Transport proteins, channel proteins, and passive carrier proteins all help increase the selective permeability of a phospholipid bilayer membrane.

d. Transport proteins, channel proteins, and passive carrier proteins all help increase the selective permeability of a phospholipid bilayer membrane.

Which of the following can be used to accurately describe viruses? a. They are small, cellular infectious agents that are only capable of reproducing when inside a living cell, and they can attack plants as well as animals. b. Each is typically a piece of genetic material encased in proteins, and they can reproduce on their own. c. They can attack plants, animals, and protozoans, and each is typically a piece of self-replicating genetic material encased in proteins. d. Typically just a piece of genetic material encased in proteins, viruses are small, non-cellular infectious agents that are only capable of reproducing when inside a living cell such as those of plants, animals, fungi, protozoans, or bacteria.

d. Typically just a piece of genetic material encased in proteins, viruses are small, non-cellular infectious agents that are only capable of reproducing when inside a living cell such as those of plants, animals, fungi, protozoans, or bacteria.

A long piece of ribbon wired along both long edges is twisted into a helix and wrapped around individual pipe cleaners that have been rolled into spools; this grouping is then twisted (super coiled) again to condense it. This could be best used as a simple model for a. a plasma membrane, where the pipe cleaners represent the phospholipid bilayer and the ribbon represents proteins embedded in the membrane. b. a cell wall. c. a mitochondrion. d. a chromosome, where the pipe cleaners represent bundles of proteins around which the DNA double helix (wired ribbon) is wrapped.

d. a chromosome, where the pipe cleaners represent bundles of proteins around which the DNA double helix (wired ribbon) is wrapped.

A factory with an office that controls the information sent to separate rooms for each of the manufacturing and shipping processes would be analogous to a. a virus. c. a prokaryotic cell without a nucleus. b. a prokaryotic cell with a nucleus. d. a eukaryotic cell with a nucleus.

d. a eukaryotic cell with a nucleus.

The leaves of a plant typically have different tissue layers that function in different ways. The epidermis layer functions like a covering of skin to protect the leaf while vascular bundles carry water and nutrients through the leaf. The palisade mesophyll layer is responsible for most of the photosynthesis that occurs while the spongy mesophyll layer underneath it aids in the exchange of gases (CO2 and O2) and water vapor. In which leaf tissues would you expect to find the highest density of chloroplasts? a. epidermis c. spongy mesophyll b. vascular bundles d. palisade mesophyll

d. palisade mesophyll

A white blood cell (WBC) encounters bacteria in a scrape on the knee of a child who has fallen off of his bicycle. The WBC's job is to take the bacteria inside of itself and destroy the bacteria. If the bacteria cannot be moved across the WBC membrane, how will the WBC most likely take it in? a. exocytosis c. facilitated diffusion b. pinocytosis d. phagocytosis

d. phagocytosis

An amoeba, a protozoan that moves by pseudopodia, approaches a smaller protozoan and extends its pseudopodia (extensions of cytoplasm in plasma membrane) around the smaller protozoan. Once the amoeba's pseudopodia completely surrounds the other protozoan, the amoeba's plasma membrane pinches off by folding back into the amoeba and creating a vesicle containing the smaller protozoan. This vesicle is now within the amoeba itself and will soon fuse with other vesicles containing digestive enzymes. This is an example of a. pinocytosis. c. osmosis. b. exocytosis. d. phagocytosis.

d. phagocytosis.

Living cells have an intact phospholipid bilayer that separates the cell from its external environment; this structure is commonly referred to as the a. nucleus. c. endoplasmic reticulum. b. mitochondria. d. plasma membrane.

d. plasma membrane.

Many important cellular functions in eukaryotic cells occur within membrane-enclosed organelles, such as cellular respiration occurring within the mitochondria. The membranes of the mitochondria provide a place for enzymes needed for cellular respiration to anchor and function. Prokaryotic cells must also carry out respiration but do not have mitochondria. Where is the most likely place that enzymes needed for cellular respiration are anchored and functioning? a. the cell wall c. the cytosol b. the chromosome d. the plasma membrane

d. the plasma membrane