BIO EXAM 5

Transport protein

Structure A in the figure is a(n) _____.

Solute

Structure A is a _____.

Transport protein

Structure B is a _____.

Smooth endoplasmic reticulum

Synthesizes lipids

D

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

plasma membrane

The _____ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell.

endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria.

The evolution of eukaryotic cells most likely involved______.

Signal transduction

The long and complex series of events that occurs when a signal binds to the cell surface and is converted from one form to another is called _____.

chloride ion

A "mystery molecule" was isolated in a laboratory and scientists found that the molecule readily crossed artificial membranes. Which of the following molecules can be ruled out as the "mystery molecule?"

signal molecule

A signal transduction pathway is initiated when a _____ binds to a receptor.

Centriole

Animal cell only

Mitochondrion, endoplasmic reticulum, Golgi apparatus, nucleus, cytoskeleton, plasma membrane

Both plant and animal cell

Plasma membrane, ribosomes, flagella

Both prokaryotic and eukaryotic

more fluid bilayers

Decreasing the saturation of the fatty acid chains on a particular type of phospholipid would result in the formation of _____.

Microtubule, intermediate filaments, plasma membrane

Defines cell shape

passive transport

Diffusion across a biological membrane is called __________________.

Lysosomes

Digests proteins

Mitochondria, lysosome, nucleolus

Eurkaryotic only

there must be cellcell communication among the cells within a tissue or organ

For a tissue or an organ to function as a unit, ________.

Mitochondrion

Generates ATP; produces chemical energy (ATP) that can power the cell

have receptors that recognize and bind the hormone molecule.

Hormones are chemical substances produced in one organ that are released into the bloodstream and affect the function of a target organ. For the target organ to respond to a particular hormone, it must _____.

(1) The new solute will diffuse from left to right to establish equilibrium. (2) The water level on the right will fall.

Imagine a beaker with solutions separated by a lipid bilayer (like what is shown in Figure 6.12, step 3). Predict what will happen after addition of a new solute to the solution on the left side, if the new solute (1) crosses the lipid bilayer readily or (2) is incapable of crossing it.

ribosomes

In a bacterium, where are proteins synthesized?

Ions cannot cross planar bilayers

In an experiment involving planar (flat) bilayers, a solution of table salt (sodium and chloride ions in water) is added on the left side of the membrane while pure water is added on the right side. After 30 minutes the researchers test for the presence of ions on each side of the membrane. The right side tests negative for ions. What can you conclude?

Gap junctions

Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through _____.

polar heads and nonpolar tails; the polar heads interact with water

Lipids that form membranes have what kind of structure?

Chloroplast

Makes sugar by converting light energy into chemical energy, contain the green pigment chlorophyll, are the sites of reactions that convert solar energy into chemical energy, have membranous sacs called thylakoids that are surrounded by a fluid called stroma

Golgi apparatus

Modifies, sorts, and packages proteins

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

More concentrated; less concentrated

Plant and animal cells both carry out cellular respiration, producing ATP

Select the correct statement describing the cellular structure or function: Plant and animal cells both carry out cellular respiration, producing ATP. Only plant cells contain chloroplasts, and only animal cells contain mitochondria. Mitochondria and chloroplasts are part of the endomembrane system of the eukaryotic cell.

Cellulose cell wall, chloroplasts, central vacuole

Plant cell only

adjacent plant cells

Plasmodesmata are cellcell junctions that are found between ________.

gap junctions

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

Rough endoplasmic reticulum

Produces secretory proteins

Nucleoid

Prokaryotic only

increasing the percentage of unsaturated phospholipids in the membrane

The membranes of winter wheat are able to remain fluid when it is extremely cold by _____.

Desmosomes

The primary role of __________ is to bind animal cells together.

C

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

Hypertonic

This cell is in a(n) _____ solution.

The physical form of the signal changes between the outside of the cell and the inside.

What does it mean to say that a signal is transduced?

Osmosis

What name is given to the process by which water crosses a selectively permeable membrane?

They serve as communication portals between neighboring plant cells, allowing the passage of small molecules between the two cells.

What role do plasmodesmata play in plant cells?

transduction

Which is the second of the three stages of cell signaling?

a small, nonpolar molecule like oxygen (O2)

Which of the following crosses lipid bilayers the fastest?

a sodium ion

Which of the following crosses lipid bilayers the slowest?

a greater proportion of unsaturated phospholipids

Which of the following factors would tend to increase membrane fluidity?

Both sodium and potassium ions are transported against their concentration gradients.

Which of the following statements is TRUE with regard to this animation?

CO2

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?

A only

Which of these can RAPIDLY pass directly through the phospholipids of the plasma membrane, without the help of a transport protein?

tight junctions

Which of these cell junctions form a barrier to the passage of materials?

B

Which of these is a membrane receptor?

B

Which of these is a receptor molecule?

A

Which of these is a signal molecule?

A

Which of these is responsible for initiating a signal transduction pathway?

Bilayers are most permeable and most fluid when they consist of shorter, unsaturated hydrocarbon tails.

Which statement most accurately describes the relationship between the permeability and fluidity properties of phospholipid bilayers and their structure?

A cell must have the appropriate receptor before it can bind to the hormone.

Why does a hormone act only on specific cell types in an organism and not others?

The membrane phospholipids of cold-adapted organisms will have more unsaturated hydrocarbon tails.

You have just discovered an organism that lives in extremely cold environments. Which of the following would you predict to be true about the phospholipids in its membranes, compared to phospholipids in the membranes of organisms that live in warmer environments?

hypertonic solution ... lost water

You know that this cell is in a(n) _____ solution because it _____.

hypotonic ... swelled

You know that this cell is in a(n) _____ solution because the cell _____.

Gap (communicating) junctions

_____ aid in the coordination of the activities of adjacent animal cells.

Nucleolus

assembles ribosomes

Passive transport

facilitated diffusion is a type of _____________.

Central vacuole

regulates cytoplasm composition, creates internal pressure, and stores cell compounds

Plant cell wall

strong, protective structure made from cellulose fibrils