ch5 bio

Which of the following molecules spontaneously form membranes when mixed in water and most likely were one of the first organic compounds formed on Earth?

Phospholipids

A characteristic of phospholipids that makes them a candidate for the first organic compounds on Earth to be related to life is their ability to __________.

Self-assembly of phospholipid molecules is spontaneous. It does not require an energy input or the presence of specific enzymes.

Diffusion ________.

proceeds until equilibrium is reached

Usually, enzymes are ________.

proteins

You have a 2-kg bottle of liquid water at 0°C. About how many Calories are needed to heat up the water to 100°C?

200 Calories

Which of these is ATP?

3 phosphate , ribosome and an adenine molecule

Humans convert approximately ________ of the energy stored in food to useful work.

34%

What compound directly provides energy for cellular work?

ATP

The figure below shows that ________.

ATP can perform cellular work when it releases a phosphate group

Cells use this molecule to store the chemical energy released by the breakdown of food molecules during cellular respiration.

ATP is responsible for fueling most energy-requiring reactions in cells.

Which of these is TRUE with regard to this animation?

An electrochemical gradient forms across the plasma membrane.

diffusion

Diffusion is the movement of particles down their concentration gradient.

Which one of the following statements about energy is correct?

Energy cannot be created or destroyed.

Which of the following is an example of potential energy?

a bowling ball placed on the top shelf of a closet

The region of an enzyme to which a substrate binds is called the ________ site.

active

The use of energy to move molecules across a membrane defines __________.

active transport

Osmosis can be defined as ________.

diffusion of water across a selectively permeable membrane

In a hypotonic solution, a plant cell will ________.

become turgid

An enzyme is a protein that __________.

changes the rate of a metabolic reaction without being consumed by the reaction

Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing ________.

chemical energy into kinetic energy

The principle that energy cannot be created or destroyed is known as ________.

conservation of energy

Enzymes increase the rate of a reaction by ________.

decreasing activation energy

The passive movement of molecules from an area of higher concentration to an area of lower concentration is called __________.

diffusion

Activation energy can be described as __________.

energy needed to activate the reactants and trigger a chemical reaction

Which of the following is a measure of randomness in a system?

entropy

Substances that plug up an enzyme's active site are ________.

enzyme inhibitors

When two solutions that differ in solute concentration are placed on either side of a selectively permeable membrane, and osmosis is allowed to take place, the water will ________.

exhibit a net movement to the side with lower water concentration

Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. Which of the following processes could be responsible for its secretion?

exocytosis

Examine the cells below. Cells with a higher concentration of ions than the surrounding medium tend to ________.

expand

This process is referred to as _____. Structure A is a _____. Structure B is a _____.

facilitated diffusion Diffusion is occurring via a transport protein. solute A solute is crossing the plasma membrane. transport protein The transport protein facilitates the movement of solute across the plasma membrane..

How do some inhibitors slow down metabolic pathways when the products of the pathways are not needed but still allow a pathway to proceed when the products are needed?

feedback regulation

In osmosis, water always moves toward the __________ solution, that is, toward the solution with the __________ solute concentration.

hypertonic ... greater ,Water moves by osmosis from the hypotonic solution toward the hypertonic solution

A cell that neither gains nor loses a net amount of water at equilibrium when it is immersed in a solution is ________.

isotonic to its environment

An object at rest has no ________ energy, but it may have ________ energy resulting from its location or structure.

kinetic... potential

An animal cell placed in a hypertonic solution will __________.

lose water by osmosis and shrivel

Catalysts speed reactions mainly by ...

lowering EA. though they may have other effects as well. With a lower EA, a larger fraction of collisions can produce the transition state.

The sum total of all the chemical reactions that occur in organisms is called ________.

metabolism

Diffusion is an example of ________.

passive transport

The act of a white blood cell engulfing a bacterium is ________.

phagocytosis

Which one of the following terms is sometimes called "cell eating"?

phagocytosis, a cell engulfs a particle and packages it within a food vacuole

Which curve shows the course of the reaction in the presence of an enzyme--the black curve or the red curve? Which line represents the activation energy for that reaction--a, b, or c? Use the graph and your knowledge of enzymes to identify the three true statements about enzymes.

red curve; line b 1)Enzymes lower the overall energy input needed for a reaction to occur. 2 )By binding to reactant molecules, enzymes make it easier for the bonds in the molecules to break apart. 3) Reactants cannot convert to products without an initial input of energy to start the reaction

Anything that prevents ATP formation will most likely ________.

result in cell death

Which component of the following reaction is the enzyme? sucrose + sucrase + water → sucrase + glucose + fructose

sucrase

What is energy?

the capacity to cause change

Entropy means that __________.

the quantity of usable energy declines with each energy transformation

If placed in tap water, an animal cell will undergolysis, whereas a plant cell will not. What accounts for this difference?

the relative inelasticity and strength of the plant cell wall

Structure A is a(n) _____. Which of these is hydrophobic like the interior of the plasma membrane?

transport protein A )Lipid soluble molecules are hydrophobic.

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.

transport proteins... down

Active transport ________.

uses ATP as an energy source can involve the transport of ions can move solutes against their concentration gradient