Relaying a message from a membrane receptor to a molecule that preforms a specific function within a cell is called
which of the following statements regarding membrane function is false
plasma membrane is control center of cell
small, non-polar, hydrophobic molecules such as fatty acids
easily pass through membranes lilpid bilayer
diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of
When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will
exhibit net movement to the side with lower water concentration
In the lab, you use a special balloon that is permeable to water, but not sucrose, to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% waterand is immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur?
water will leave ballon
A cell that never gains nor loses water when it is immersed in a solution is
isotonic to its environment
If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference?
the relative inelasticity and strength of plant cell wall
Facilitated diffusion across a biological membrane requires ___________ and moves substance ____________ its concentration gradient
transport proteins, down
which of the following statements is true among all types of passive diffusion
the concentration gradient is the driving force
which of the following processes can move a solute against its concentration gradient
active transport is driven by concentration gradient
Which of the following processes could result in the net movement of a substance into a cell, if the substance is more concentrated in the cell then in the surroundings?
Certain cells that line the stomach synthesize a digestive enzyme and secret it into the stomach. This enzyme is protein. Which of the following processes could be responsible for its secretion?
A steer must eat at least 100 pounds of grain to gain less then 10 pounds of muscle tissue. This illustrates
the second law of thermodynamics
What is the basic difference between exergonic and endergonic reactions?
Exergonic reactions release energy; endergonic reactions absorb it
during which of the following stages of food processing is undigested material removed from the digestive tract
which of the following choices lits the organs of the bird digestive system in the correct order, from first to last contact with food material
mouth, esophagus, crop, stomach, gizzard, intestine, anus
the digestion of carbohydrates begins in the mouth, what is the name given to the starch-digesting enzyme secretes by salivary glands?
the function of the pyloric sphincter is to
controls what goes from the stomach to the small intestine
epithelial cells lining the intestine have surface projections that increase nutrient absorption, these projections are called
Interestingly, most herbivorous animals do not have the ability to digest cellulose in plants. However, in the absence of this ability, they have evolved a mechanism that allows them to survive despite eating only plant matter, namelt
which of the following digestive system structures is greatly expanded in size in koalas, resulting in a very large surface area for prokaryotes to digest plant matter
a material that must be ingested in preassembles form because the animal cannot synthesize it is
essential amino acids