Homework #5: Dynamic Cell
The concentration of calcium in a cell is 3%. The concentration of calcium in the surrounding fluid is 1%. Which of the following processes could the cell use to obtain more calcium?
Active transport
Which of these words should be classified separately from the others?
Active transport
Which of the following is a passive process?
facilitated diffusion
What process allows water to move across a cell membrane?
osmosis
Considering the ATP cycle, which of the following would have the most potential energy to perform work for cell activities?
ATP
Enzymes are able to speed up the rate of a reaction by
lowering the energy needed for the reaction to proceed.
Which of the following statements about ATP is inaccurate?
ATP is comprised of a sugar, base, and two phosphate groups.
Eggs are often preserved in a 20-30% salt solution called brine. How does this method prevent contamination by microorganisms?
Bacteria can't survive in a hypertonic solution because they lose water.
Which of the following statements correctly describes an energy transformation in living organisms?
Chloroplasts convert solar energy to the chemical energy of nutrient molecules.
Which of the following statements most accurately describes the first law of thermodynamics?
Energy can neither be created nor destroyed, but it can be changed from one form to another.
ATP releases energy when
a phosphate is removed
ATP breakdown provides the energy necessary for building a protein. This is an example of which concept?
coupled reactions
When a car burns gasoline, much of the energy is released in the form of heat. Which of the following best describes this process in relation to the first law of thermodynamics?
energy can be changed from one form to another
Which of the following is an example of simple diffusion?
sugar cube dissolves in coffee
What prevents a plant cell from bursting in a hypotonic solution?
the presence of a cell wall
Which of the following is an example of osmosis?
Cells in our kidneys reabsorb water to reduce the amount of water lost in our urine.
A tube with a membrane covering the bottom is placed in a beaker. The membrane allows water to flow through but not salt or glucose. If the tube contains an aqueous solution with 12% salt and 6% glucose and the beaker contains an aqueous solution with 13% salt and 10% glucose, what would happen to the level of the water in the tube?
The level of the solution in the tube would lower because there are more dissolved solutes present in the beaker.
Which of the following is an example of potential energy rather than kinetic energy?
a bowl of oatmeal made up of energy-rich macromolecules
The part of the enzyme into which the substrate fits is called the
active site
Which of the following terms best describes entropy?
disorder
Simple diffusion across a plasma membrane is called passive transport because it
does not requite energy from a cell
Simple diffusion of molecules occurs
in non-living systems as well as living systems.
The changing of an enzyme's shape as the substrate binds to the active site is called the
inducted fit model
If the concentration of the solute is the same in the cell as it is in the surrounding solution, the cell is in a(n)________ environment.
isotonic
ATP is a good source of energy for a cell because
it breakdown is coupled with energy-requiring reactions.
When an enzyme is present
less energy is needed to bring about a reaction.
If blood cells are placed in a hypotonic solution, the cells will
swell due to osmosis
Which of the following is a mechanism used to regulate enzyme activity?
feedback inhibition
The second law of thermodynamics states that all energy transformations result in an increase in entropy (disorder). If so, how does photosynthesis, which is an energy transformation, create order rather than disorder?
The tree takes in small disordered molecules like carbon dioxide from the air and water from the earth and using solar energy produce highly ordered sugar molecules like glucose.
Molecules move from greater to lesser concentration through a carrier protein in
facilitated diffusion
Which of the types of cellular activities listed below can proceed without ATP energy?
passive transport
