Biology UNIT 2

________ is the self-replicating material present in nearly all living organisms; it is the main constituent of chromosomes and the carrier of genetic information.

DNA

Why doesn't the antibiotic penicillin harm humans? a.) Human cells do not have cell walls. b.) Penicillin attacks plasma membranes. c.) Penicillin attacks the nervous system. d.) The dosage given to kill bacteria is e.) too low to harm humans.

a.) Human cells do not have cell walls.

Which of these statements is TRUE with regard to this animation? a.) The cell does not expend ATP. b.) Sodium and potassium ions are transported against their concentration gradients. c.) Potassium ions are transported down their concentration gradient. d.) The cell is not expending energy. e.) Sodium ions are transported down their concentration gradient.

b.) Sodium and potassium ions are transported against their concentration gradients.

The primary role of _____ is to bind animal cells together. a.) the cytoskeleton b.) desmosomes c.) gap (communicating) junctions d.) plasmodesmata e.) tight junctions

b.) desmosomes

What carries instructions for making proteins from the nucleus into the cytoplasm? a.) DNA b.) ATP c.) mRNA d.) Rough ER e.) ribosomes

c.) mRNA

Where is a bacterial cell's DNA found? a.) ribosomes b.) nucleus c.) peroxisome d.) nucleoid region e.) capsule

d.) nucleoid region

What structure acts as a selective barrier, regulating the traffic of materials into and out of the cell? a.) cytoskeleton b.) extracellular matrix c.) nuclear envelope d.) plasma membrane e.) endomembrane system

d.) plasma membrane

Which of the following is part of the endomembrane system? a.) cytoskeleton b.) ribosomes c.) flagellum d.) mitochondria e.) Golgi apparatus

e.) Golgi apparatus

The structure that regulates the passage of material into and out of this bacterial cell is indicated by the letter _____.

C

__________________ are tightly coiled bundles of DNA and protein found in the nucleus of most living cells.

Chromosomes

The DNA-containing region of this bacterial cell is indicated by the letter _____.

D

___________ is used in all steps of protein synthesis and carries the genetic information of many viruses.

RNA

Diffusion across a biological membrane is called

passive transport

The plant cell wall a.) is a protective structure made of cellulose fibrils. b.) is found just inside the plasma membrane. c.) is very similar to the animal cell wall. regulates the composition of the cytoplasm. d.) makes food by converting light energy to chemical energy.

a.) is a protective structure made of cellulose fibrils.

What is the function of a bacterium's capsule? a.) DNA storage b.) propulsion c.) protein synthesis d.) protection

d.) protection

_____ are found only in plant cells, but _____ are found in both plant and animal cells. a.) Chloroplasts; central vacuoles b.) Cell walls; chloroplasts c.) Lysosomes; plasma membranes d.) Central vacuoles; ribosomes e.) Plasma membranes; mitochondria

d.) Central vacuoles; ribosomes

Which statements about the fluid mosaic structure of a membrane are correct? Select the three correct statements. 1 The framework of a membrane is a bilayer of phospholipids with their hydrophilic heads facing the aqueous environment inside and outside of the cell and their hydrophobic tails clustered in the center. 2 The diverse proteins found in and attached to membranes perform many important functions. 3 The kinky tails of some proteins help keep the membrane fluid by preventing the component molecules from packing solidly together. 4 Membranes include a mosaic, or mix, of carbohydrates embedded in a phospholipid bilayer. 5 Because membranes are fluid, membrane proteins and phospholipids can drift about in the membrane.

1,2,5

You are working on a team that is designing a new drug. In order for this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule enters the cell? A) blood or tissue type of the patient B) non-polarity of the drug molecule C) lack of charge on the drug molecule D) similarity of the drug molecule to other molecules transported by the target cells E) lipid composition of the target cellsʹ plasma membrane

D) similarity of the drug molecule to other molecules transported by the target cells

Which of the following is a difference between active transport and facilitated diffusion? a.) Active transport requires the expenditure of cellular energy, and facilitated diffusion does not. b.) Facilitated diffusion can move solutes against a concentration gradient, and active transport cannot. c.) Active transport involves transport proteins, and facilitated diffusion does not. d.) Facilitated diffusion involves transport proteins, and active transport does not.

a.) Active transport requires the expenditure of cellular energy, and facilitated diffusion does not.

Which of the following is a function of the central vacuole? a.) Storing compounds produced by the cell b.) Working with mRNA to synthesize proteins c.) Converting light energy to chemical energy d.) Separating the cell from its surroundings e.) Storing the genetic information of the cell

a.) Storing compounds produced by the cell

Taq polymerase is an enzyme isolated from the organism Thermophilus aquaticus. This organism has been found living in the hot springs of Yellowstone National Park. This enzyme is used to copy human DNA from crime scenes. Most reactions are performed at ranges similar to those of the human body; however, what considerations should be made for optimum use of this enzyme? a.) The temperature should be raised. b.) Nothing should be altered. c.) The enzyme will not work on human DNA. d.) The pH should be decreased.

a.) The temperature should be raised.

The _____ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell. a.) plasma membrane b.) nucleoid region c.) ribosome d.) fimbriae e.) cell wall

a.) plasma membrane

Chemical energy is a form of _____ energy. a.) potential b.) kinetic c.) motion d.) heat e.) entropic

a.) potential

In a bacterium, where are proteins synthesized? a.) ribosomes b.) nucleus c.) peroxisome d.) nucleoid region e.) capsule

a.) ribosomes

Where are lipids made in the cell? a.) smooth endoplasmic reticulum (ER) b.) ribosomes c.) Golgi apparatus d.) rough endoplasmic reticulum (ER) e.) mitochondria

a.) smooth endoplasmic reticulum (ER)

Which of these cell junctions form a barrier to the passage of materials? a.) tight junctions b.) gap (communicating) junctions c.) plasmodesmata d.) desmosomes (anchoring junctions) e.) keratin fibers

a.) tight junctions

_____ aid in the coordination of the activities of adjacent animal cells. a.) Keratin fibers b.) Gap (communicating) junctions c.) Desmosomes d.) Tight junctions e.) Plasmodesmata

b.) Gap (communicating) junctions

The structural framework in a cell is the a.) endoplasmic reticulum (ER). b.) cytoskeleton. c.) plasma membrane. d.) extracellular matrix. e.) endomembrane system.

b.) cytoskeleton.

A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via __________. a.) passive transport b.) endocytosis c.) osmosis d.) active transport

b.) endocytosis

Cells A and B are the same size and shape, but cell A is metabolically quiet and cell B is actively consuming oxygen. Oxygen will diffuse more quickly into cell _____ because _____. a.) A ... the diffusion gradient there is shallower b.) A ... its membrane transport proteins will not be saturated c.) B ... the diffusion gradient there is steeper d.) B ... the oxygen molecules inside cell B have a higher kinetic energy

c.) B ... the diffusion gradient there is steeper

__________ is the most prevalent glycoprotein in the extracellular matrix a.) Enzyme b.) Integrin c.) Collagen d.) Hemoglobin

c.) Collagen

_____ are surface appendages that allow a bacterium to stick to a surface. a.) Mitochondria b.) Ribosomes c.) Fimbriae d.) Flagella e.) Cell walls

c.) Fimbriae Fimbriae enable bacterial cells to stick to a surface.

Which plant cell organelle converts chemical fuel into packets of chemical energy that can power the cell? a.) Chloroplast. b.) Plasma membrane. c.) Mitochondrion. d.) Golgi apparatus. e.) Central vacuole.

c.) Mitochondrion.

Which of the following describes the function of the chloroplast? a.) The chloroplast serves as a protein manufacturing facility. b.) The chloroplast creates internal pressure for a cell. c.) The chloroplast converts light energy to chemical energy. d.) The chloroplast stores compounds produced by the cell. e.) The chloroplast functions as the site of lipid synthesis.

c.) The chloroplast converts light energy to chemical energy.

Part complete What name is given to the rigid structure, found outside the plasma membrane, that surrounds and supports the bacterial cell? a.) capsule b.) fimbriae c.) cell wall d.) flagella e.) nucleoid region

c.) cell wall

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP? a.) potentiation b.) redox c.) cellular respiration d.) anabolism e.) digestion

c.) cellular respiration

"Conservation of energy" refers to the fact that _____. a.) the net amount of disorder is always increasing b.) no chemical reaction is 100 percent efficient c.) energy cannot be created or destroyed but can be converted from one form to another d.) if you conserve energy you will not be as tired e.) the entropy of the universe is always increasing

c.) energy cannot be created or destroyed but can be converted from one form to another

Which of the following organelles breaks down worn-out organelles? a.) smooth endoplasmic reticulum (ER) b.) rough endoplasmic reticulum (ER) c.) lysosomes d.) Golgi apparatus e.) mitochondria

c.) lysosomes

Where in a cell is ATP made? a.) ribosomes b.) lysosomes c.) mitochondria d.) cytoskeleton e.) nucleus

c.) mitochondria

The synthesis of an amino acid follows this pathway: precursor A > intermediate B > amino acid C. Each reaction is catalyzed by a different enzyme. This metabolic pathway is controlled by feedback inhibition with amino acid C inhibiting the conversion of precursor A to intermediate B. Amino acid C acts as a _____ of the first enzyme in the pathway. a.) competitive inhibitor b.) substrate c.) noncompetitive inhibitor d.) catalyst

c.) noncompetitive inhibitor

Where is the genetic information of the cell stored? a.) Golgi apparatus b.) rough endoplasmic reticulum (ER) c.) nucleus d.) smooth endoplasmic reticulum (ER) e.) lysosomes

c.) nucleus

When in solution, a molecule that moves slowly across an artificial membrane moves rapidly across a plasma membrane. This molecule rapidly enters the cell regardless of whether its concentration is higher inside or outside the cell. Using this information, which transport mechanism is most likely to be responsible for the movement of the molecule across a plasma membrane? a.) phagocytosis b.) passive transport c.) exocytosis d.) active transport

d.) active transport

Azidothymidine (AZT) is an antiretroviral drug used in the treatment of HIV. It shares a structural similarity to a nucleotide. What might be the mode of action for this drug? a.) feedback inhibition b.) mixed inhibition c.) noncompetitive inhibition d.) competitive inhibition

d.) competitive inhibition

Which of these are by-products of cellular respiration? a.) water b.) ATP and water c.) ATP d.) heat and water e.) glucose and water

d.) heat and water

In plants, __________ are the cell junctions that allow the free exchange of small molecules that assist in communication. In animal cells, similar cell junctions are known as __________. a.) plasmodesmata ... anchoring junctions b.) anchoring junctions ... gap junctions c.) tight junctions ... anchoring junctions d.) plasmodesmata ... gap junctions

d.) plasmodesmata ... gap junctions

In this diagram of the plasma membranes of two adjoining cells, identify the protein indicated by the white arrow, including its function. a.) an attachment protein that provides structural support b.) a protein involved in enzymatic activity c.) a glycoprotein that is involved in cell-cell recognition d.) an active transport protein that moves molecules across a membrane against their concentration gradient e.) a receptor protein that binds with a signaling molecule and relays the message into the cell by activating other molecules inside the cell

e.) a receptor protein that binds with a signaling molecule and relays the message into the cell by activating other molecules inside the cell

Which of these is exhibiting kinetic energy? a.) a rock on a mountain ledge b.) the high-energy phosphate bonds of a molecule of ATP c.) a person sitting on a couch while watching TV d.) an archer with a flexed bow e.) a space station orbiting Earth

e.) a space station orbiting Earth

One of the ways smooth endoplasmic reticulum (ER) differs from rough endoplasmic reticulum is that rough ER is covered by a.) the cytoskeleton. b.) the Golgi apparatus. c.) the extracellular matrix. d.) mitochondria. e.) ribosomes.

e.) ribosomes.

When molecules move down their concentration gradient, they move from where they are _________________ to where they are __________________.

more concentrated; less concentrated

The ___________________ is the two-layered membrane that encases the nucleus of a eukaryotic cell, separating the nucleus from the cytoplasm.

nuclear envelope

A protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm is called a ________________.

nuclear pore

The round body that sits inside the nucleus of a eukaryotic cell and makes ribosomal subunits from proteins and ribosomal RNA is known as the ______________.

nucleolus

The ___________ is the most prominent membrane-bound organelle in eukaryotic cells, and it houses most of a cell's DNA.

nucleus