Chapter 3: The Cellular Level

Symporters couple

facilitated diffusion of one ion to the active transport of another ion or molecule

Benzene is a nonpolar molecule. With which of the following parts of the phospholipid molecule would it best be able to interact?

fatty acid chains

An important component in keeping plasma membranes fluid ________ can also be converted into steroid hormones and bile salts.

cholesterol

A _________ is the term for having a difference in the percentage of solutes from one side of the membrane to the other.

concentration gradient

The three main parts of the cell include the nucleus, the plasma membrane, and the __________.

cytoplasm

Which part of a human cell has the organelles suspended in it?

cytoplasm

Another name for the intracellular fluid is the ________ . This fluid, together with organelles, make up the cytoplasm.

cytosol

A process that uses vesicles to transport substances across the plasma membrane is

endocytosis

An integral protein that binds to a substrate and catalyzes a reaction is a(n)

enzyme; each is specific for a certain molecule

Which of the following would be found in the nucleus? Select all that apply.

-DNA -chromatin -ribosomes -nucleolus

You have a beaker in which two separate solutions are separated by a semi-permeable membrane. Side A contains a 0.85% sodium ion solution. Side B contains a 10% chloride ion solution. Which is the following is true of this beaker? Select all that apply.

-There exists a concentration gradient between the two sides. -There exists an electrochemical gradient between the two sides. -There exists an electrical gradient between the two sides.

Which of the following can contribute to the aging of cells? Select all that apply.

-autoimmune response -free radicals -telomeres -high levels of stress

Which of the following are components found in the cytoplasm? Select all that apply.

-cytosol -cytoskeleton -lysosomes

Which of the following can be found in the cytoplasm? Select all that apply.

-cytosol -organelles -lysosomes -cytoskeleton

When are chromatids found in a cell? Select all that apply.

-during cell division -just prior to cell division

What factors can increase the rate of diffusion across a permeable membrane? Select all that apply.

-high temperatures -smaller the mass of the molecule -large membrane surface area

Which of the following applies to the plasma membrane of cells? Select all that apply.

-isolation of the internal cell environment from the external environment -selectively permeable -described by the fluid mosaic model

Which of the following would you find floating in the cytosol of a cell? Select all that apply.

-mitochondria -ribosomes

A frequent problem in cancer cells is that cell division happens without the chromosomes being fully packed. This could be a problem with the formation of which of the following structures? Select all that apply.

-nucleosome -chromatin fiber -Chromatid

Which parts of the plasma membrane contribute to membrane fluidity? Select all that apply.

-the amount of cholesterol present -the number of double bonds in phospholipid chains

Which of the following is/are found in the cytosol? Select all that apply.

-water -suspended particles -dissovled solutes -organelles

What percentage of the membrane lipids are glycolipids?

5%

What percentage of the membrane lipids are phospholipids?

75%

In a normal human somatic cell that is undergoing mitosis, how many chromatids will be present?

92

Tay Sachs disease is a disorder that occurs in the lysosomes of affected people. Based on this information, which of the following would be a true statement about people who suffer from Tay Sachs disease?

An organelle in the cytoplasm is directly affected by this disease.

Cells have the ability to divide an unlimited number of times.

False

Which of the following names a molecule that can cross the plasma membrane by facilitated diffusion and includes a correct reason for that method of movement?

K+, because it is polar and cannot interact with the interior of the plasma membrane

If the plasma membrane of a cell becomes more permeable than normal, which of the following might occur as a direct result?

The water balance of the cell might be compromised.

There are approximately 200 different types of cells in the human body. Almost all of these cells have three main parts; however, this is not universally true. Red blood cells, for example, are missing

a nucleus

Certain cells in the thyroid gland import iodine in order to make thyroid hormone. The iodine concentration in these cells is approximately 10,000 times greater than the iodine concentration in the plasma surrounding these cells. Therefore, the process by which iodine enters these cells must be

active transport

Proteins that are embedded in the plasma membrane must be __________.

amphipathic

The LMNA gene encodes specialized intermediate filaments that are a critical part of support for the nucleus. A mutation in this gene causes improperly-formed intermediate filaments. Which of the following would be a likely result of this mutation?

an abnormally-shaped nuclear envelope

Integral proteins that serve as enzymes may ___________.

be oriented either to the cytoplasm or to the extracellular fluid

Glycolipids are made up of which two types of molecule?

carbohydrates and lipids

The interior of the plasma membrane is hydrophobic; therefore, which of the following molecules can use simple diffusion to cross from the extracellular fluid to the cytoplas

carbon dioxide

What type of integral protein serves to transport ions across the membrane?

channels

Electrical currents or chemicals can be used as stimuli to open or close channels.

gated

Cross-linking between adjacent proteins is a result of _________ molecules, and it is a normal occurrence when a person ages.

glucose

The backbone of a phospholipid molecule is a ________ molecule, which is attached to two hydrophobic tails and a phosphate head group.

glycerol

The sugar molecules that are associated with the plasma membrane form a coating known as the _________.

glycocalyx

A molecule composed of both carbohydrates and lipids that is present in the plasma membrane is a _________.

glycolipid

Which of the following membrane components would be found only in the portion of the lipid bilayer that faces the extracellular fluid?

glycolipids

The glycocalyx is formed from portions of which of the following molecules?

glycoproteins and glycolipids

The immune system recognizes cell-identity markers that are found on the plasma membrane; these markers are often made of _________.

glycoproteins and glycolipids

What keeps sodium ion channels from flipping 180-degrees and transporting sodium ions the opposite direction?

hydrophilic parts of the channel cannot pass through hydrophobic parts of the membrane

Since phospholipid molecules make up the majority of the plasma membrane, integral proteins must have a sequence that includes _______ amino acids in the interior of the membrane to interact with the phospholipids.

hydrophobic

Where would you find the rough endoplasmic reticulum of a cell?

in the cytosol

Vasopressin is a hormone that acts to _________ blood pressure by increasing the reabsorption of water from the filtrate into the bloodstream. It does so by inserting special water channels, known as aquaporins (AQPs) into the collecting duct of the kidney.

increase

"Lipid rafts" can be found in the plasma membrane as anchoring sites for membrane proteins. These rafts contain long-chained phospholipids and cholesterol molecules, and the membrane is thicker in these locations. What is the purpose of the cholesterol in a lipid raft?

it helps the lipids aggregate so the raft stays together

Secondary active transport processes are driven by the release of what type of energy?

kinetic

A mutation in the telomeres that allowed them to stay long even when the cell undergoes mitosis could contribute to a(n)

longer lifespan for the cell

Which of the following is a function of peripheral proteins?

movement of organelles inside the cell

Most of the DNA in a cell is found in the

nucleus

The genes of a cell are found in the

nucleus

___________ are subcellular structures with specific functions that are suspended in the cytoplasm.

organelles

Water molecules that move into the nucleus will enter via __________.

passive diffusion

____________ proteins help move organelles around inside the cell, particularly those close to the plasma membrane.

peripheral

A protein attached to membrane lipids but not embedded in the membrane is a(n) __________.

peripheral proteins, which are hydrophilic

DNA polymerase III is an enzyme required for DNA replication prior to cell division. This protein is produced on ribosomes found outside of the nucleus; however, DNA is replicated inside of the nucleus. How does this enzyme get into the nucleus?

primary active transport

The insulin ________ is a type of membrane protein that binds to a ligand known as insulin so that glucose can be transported into liver cells.

receptor

Which type of integral protein can be bound by a ligand?

receptors

If a membrane were permeable to both sodium ions and potassium ions at once, which direction would each one move?

sodium ions would move into the cell; potassium ions would move out of the cell

What are the relative sodium and potassium levels in relation to the plasma membrane?

sodium is high outside the cell and potassium is high inside the cell

The_________ are DNA sequences that are found at the ends of each of the chromosomes.

telomeres

Which of the following is a component that helps make a plasma membrane "fluid"?

the amount of cholesterol present

Which of the following might be a research avenue for a gerontologist?

the cross-linking of protein fibers with glucose molecules

Which part(s) of the phospholipid is/are nonpolar?

the fatty acid chains

Which part(s) of the phospholipid molecule is/are amphipathic?

the molecule overall

The interior of the cell is negatively charged compared to the extracellular fluid. As a result of the electrical gradient between the two areas,

there will be a net movement of sodium ions into the cell.

The doctor just told your patient that she has a neoplasm. She doesn't understand this term. What other term can you give her for this diagnosis?

tumor