Chapter 4: The energy of Life
Organisms transform energy from one form to another. Put the following forms of energy in the order that they are harvested and converted, starting at the top with a form of energy that is not in an organism.
1. Sunlight is captured 2. Sugars are synthesized in plants and some microbes 3. Sugars are broken down to liberate energy that powers cellular activities.
What happens during receptor-mediated endocytosis?
A cell brings substances that bind to membrane receptors into the cell.
ATP can be synthesized by the addition of a phosphate group to a molecule of ______, which is a reaction that requires energy.
ADP
Adenosine diphosphate is also known as
ADP
When the endmost phosphate group is removed from ATP, what molecule is produced?
ADP
The sodium-potassium pump uses energy in the form of ______ to move ions against their concentration gradients.
ATP
What molecule temporarily stores energy in cells?
ATP
In eukaryotic cells, the breakdown of glucose molecules in organelles called mitochondria generates most of the cell's supply of
ATP molecules
The energy molecule ____ is not stored in large quantities in cells because its high-energy phosphate bonds are too unstable.
ATP or Adenosine triphosphate
____ is the term that describes all the chemical reactions that occur in a cell, including the building of molecules and breaking down of molecules.
Blank 1: Metabolism, Cellular metabolism, metabolism, metabolic pathways, or Cell metabolism
An example of an energy-requiring reaction is ____, which uses energy from the sun to produce sugars; an example of an energy-releasing reaction is cellular ____, which releases the energy in sugars.
Blank 1: photosynthesis Blank 2: respiration
Stored energy that can be used to do work is called ____ energy, while energy of motion that is being used to do work is called ____ energy.
Blank 1: potential or potential energy Blank 2: kinetic or kinetic energy
What type of membrane transport is shown in the picture and requires a carrier molecule, but not ATP?
Facilitated diffusion
True or false: A phosphate group can be removed from ATP but cannot be replaced.
False
In what process does a cell capture large particles in vesicles and bring them into the cell?
Phagocytosis
____ is a type of endocytosis used by cells to engulf bulk matter, including debris and other cells.
Phagocytosis or phagocytosis
Energy-requiring reaction
Products contain more energy than reactants Products contain more energy than reactants
Energy-releasing reaction
Reactants contain more energy than products
What provides the constant stream of incoming energy that allows organisms to maintain their organization and stay alive?
The sun
Select all of the following that may result when ATP transfers a phosphate group to a target molecule.
The target molecule becomes more likely to bond with other molecules. The target molecule changes shape.
True or false: Living organisms would not be able to survive without enzymes because reactions would proceed too slowly.
True
True or false: The more disordered a system is, the higher its entropy.
True
______ pressure is the force of water against a plant cell wall and helps maintain the shape of plant cells.
Turgor
If a solute is more concentrated in one location than another, it forms
a concentration gradient.
potential energy
a sandwich; a concentration gradient of a chemical that has not dissipated
The amount of energy required to start a reaction is called the _____ energy.
activation
The region where a substrate (reactant) binds to an enzyme is called the ______ site.
active
A substance is moved from an area where its concentration is low to an area where its concentration is high with the expenditure of energy in
active transport
The sodium-potassium pump moving Na+ out of the cell and K+ into the cell against their concentration gradients is an example of ______.
active transport
What type of membrane transport requires energy (ATP) and transport proteins?
active transport
What type of movement across membranes is shown in the picture and requires a transport protein and ATP?
active transport
Select all of the components of an ATP molecule.
adenine ribose three phosphate groups
ATP stands for ______ triphosphate, which is a molecule that powers many cellular reactions.
adenosine
The sodium-potassium pump requires energy because both sodium and potassium ions move ______ their concentration gradients.
against
How do enzymes speed up biochemical reactions?
by lowering the activation energy
The amount of energy required to raise the temperature of 1 g of water 1οC is equal to 1
calorie
At the end of a biochemical reaction, the enzyme
can be reused
One energy law states that energy cannot be created or destroyed; it can only
change forms
The potential energy stored in covalent bonds is also called ______ energy.
chemical
Select all of the following that are examples of potential energy.
compressed spring chemical energy stored in bonds ball at the top of a hill
After a concentration gradient disappears, molecules
continue to move randomly back and forth.
In ______, ATP hydrolysis produces energy that drives a reaction that requires energy.
coupled reactions
In ATP hydrolysis, the ______ between the phosphate groups in ATP are broken, and energy is released.
covalent bonds
Where is the most energy stored in an ATP molecule?
covalent bonds between phosphate groups
The spontaneous movement of a substance from an area where it is more concentrated to an area where it is less concentrated is called ______.
diffusion
The solute molecules in this illustration of simple diffusion are moving ______ a concentration gradient to disburse throughout the cup.
down
A group of proteins aligned in a membrane can form a(n) ______ transport chain, which releases energy at each step in the chain and plays a role in both photosynthesis and respiration.
electron
In oxidation-reduction reactions, energized ______ are transferred from one reactant to another.
electrons
In a process called ______, a cell engulfs material and brings it into the cell in a vesicle pinched off the cell membrane.
endocytosis
Pinocytosis is a type of ______.
endocytosis used by cells to engulf fluids and dissolved substances
A concentration gradient will dissipate unless ______ is expended to maintain a higher concentration in one area compared to the other.
energy
ATP hydrolysis releases the endmost phosphate group from ATP, producing ADP, the free phosphate group, and
energy
In a coupled reaction, the ______ released from one reaction can be used to drive another reaction.
energy
In an electron transport chain, ______ is captured from electrons as they are passed between proteins called electron carriers.
energy
The ability to do work is called ______.
energy
In passive transport, no ____ is spent to pass a substance across a membrane.
energy, ATP, chemical energy, direct expenditure of energy, energy input, or energy atp
Living organisms are able to increase in complexity due to a constant input of ______ from the sun, but because the universe as a whole is also decreasing in complexity by a greater amount, the ______ in the universe is always increasing.
energy; entropy
The measure of randomness or disorder in a system is called
entropy
After a product is released from its active site, a(n) ______ can be used again in another reaction because it is not consumed or altered in the reaction.
enzyme
What organic molecules catalyze (speed up) chemical reactions?
enzymes
Without ______, many reactions would occur too slowly for an organism to survive.
enzymes
At equilibrium, molecules continue to move back and forth between areas of solution at ______ rates, creating ______ concentrations throughout a solution.
equal; equal
In a membrane transport process called ______, a cell transports large molecules to the cell membrane in vesicles and releases them to the outside of the cell.
exocytosis
In an example of ______, hydrogen ions move from high concentration to low concentration through a membrane protein, releasing energy in the process.
facilitated diffusion
Membrane proteins assist ions and polar molecules across membranes down their concentration gradient in
facilitated diffusion
Membrane proteins called aquaporins allow ______ of water across membranes, as the movement of water solely by osmosis can be slow.
facilitated diffusion
As a reaction's products accumulate, the reaction rate slows or stops due to negative ____.
feedback or inhibition
kinetic energy
fish swimming; the sound of a horn
A concentration ______ occurs when there are unequal amounts of a solute in neighboring regions.
gradient
According to the laws of thermodynamics, all energy transformations are inefficient because every reaction loses some energy to the surroundings as
heat
All energy eventually becomes ______, which is disordered energy that results from the random movements of molecules.
heat
A substance moving from an area where its concentration is ______ to an area where its concentration is ______ is moving down its concentration gradient.
higher; lower
If a solution has a higher solute concentration than a cell, then the solution is ______ compared to the cell.
hypertonic
If more water is exiting a human red blood cell than entering it, then the cell is in a(n) ______ solution.
hypertonic
If a solution has a lower solute concentration than the interior of a cell, then the solution is ______ compared to the cell interior.
hypotonic
If more water is entering a human red blood cell than exiting it, then the cell is surrounded by a(n) ______ solution.
hypotonic
According to physical laws, energy transformations overall lead to ______ disorder.
increased
In an isotonic solution, the solute concentration
is equal between two neighboring areas
If an equal amount of water enters and exits a human red blood cell, then the cell's interior is ______ to the cell's exterior.
isotonic
One food Calorie (with an uppercase "C") is actually one ______, which is equal to 1,000 calories (with a lowercase "c").
kilocalorie
The energy being used to do work is called ____ energy and is the energy of motion.
kinetic
Photosynthesis converts the ______ energy in sunlight into the ______ energy in sugars.
kinetic; potential
Select all of the substances that can pass freely through the membrane by simple diffusion.
lipids small, nonpolar molecules oxygen carbon dioxide
In diffusion, a chemical concentration gradient dissipates, and thus diffusion represents the ______ of potential energy and does not require energy input.
loss
The concentrations of solutes between the interior and the exterior of a cell or organelle may be chemically different because the ______ is selectively permeable.
membrane
The production of new molecules and the breakdown of old molecules in the cell is called
metabolism
Most of the ATP molecules in eukaryotic cells are made in organelles called ______ during cellular respiration.
mitochondria
facilitated diffusion
movement of solutes from high to low concentration with a transport protein
simple diffusion
movement of solutes from high to low concentration without a transport protein
active transport
movement of solutes from low to high concentration with a transport protein
osmosis
movement of water from areas of high water concentration (low solute concentration) to areas of low water concentration (high solute concentration) movement of water from areas of high water concentration (low solute concentration) to areas of low water concentration (high solute concentration)
Select all of the following that are true about the sodium-potassium pump.
moves potassium into the cell up its concentration gradient moves sodium out of the cell up its concentration gradient requires ATP
Competitive and noncompetitive inhibition are two mechanisms of
negative feedback
The process in which a reaction's products inhibit the enzyme that catalyzes the reaction is called
negative feedback
A product molecule blocks enzyme activity by binding to a location other than the active site during ______ inhibition; on the other hand, a product molecule blocks enzyme activity by binding directly to the active site during ______ inhibition.
noncompetitive; competitive
Like the subunits of DNA and RNA, ATP is a type of
nucleotide
The diffusion of water across a membrane down its own concentration gradient and toward the region with a higher solute concentration is called
osmosis
The image shows the diffusion of water across a selectively permeable membrane, which is called ______.
osmosis
A(n) ______ reaction occurs when an atom or molecule loses an electron, along with a corresponding loss of energy.
oxidation
The loss of an electron from an atom or a molecule is called ______.
oxidation
Redox reactions occur simultaneously: for every molecule that is reduced (gains electrons), another molecule is ______ (loses electrons).
oxidized
What is the process whereby an ion, an atom, or a molecule crosses a membrane without using energy?
passive transport
In diffusion, a substance moves by ______.
passive transport to a region where the substance is less concentrated
ATP releases energy when it donates a ______ group to another molecule.
phosphate
An ATP molecule is unstable and primed to release energy because its ______ groups are negatively charged and repel each other.
phosphate
A concentration gradient is a form of ______ energy because energy that can be used to drive molecular motion is stored in the gradient.
potential
The stored energy available to do work is called ______ energy.
potential
The energy contained in the covalent bonds of molecules is a form of ______, which can be converted to kinetic energy that the cell can use to do work.
potential energy
Although a small number of enzymes are RNA, most enzymes are ______.
proteins
Simple diffusion does not require energy because it is a result of ______ molecular motion.
random
One way that enzymes speed up reactions is to bring the ______ of the reaction together.
reactants
In a process called ______, molecules to be brought into the cell first bind to receptor proteins on the cell's surface, and then a vesicle forms and brings the molecules into the cell.
receptor-mediated endocytosis
Select all of the following essential cellular activities that are conducted by enzymes.
recycling of cell parts DNA replication breakdown of food protein production
When an atom or a molecule has gained an electron, it has been ______.
reduced
A(n) ______ reaction occurs when an atom or a molecule gains an electron, and its energy.
reduction
Select all of the cellular conditions that affect enzyme activity.
salt concentration pH temperature
Membranes of organelles and cells only allow specific ions, atoms, and molecules to pass because membranes are
selectively permeable.
Substances such as lipids and small nonpolar molecules move freely through the cell membrane without the need for transport proteins in a process called
simple diffusion
The movement of substances down their concentration gradient without the use of transport proteins is called ______.
simple diffusion
What type of membrane transport is shown in the picture and lacks a carrier molecule?
simple diffusion
Warmer temperatures generally ______ enzymatic activity, but when temperatures increase too much, enzymes denature.
speed up
Select all types of molecules that cells use for long-term energy storage.
starch fats glycogen
Only specific ______ can bind to an enzyme's active site, and each particular enzyme can only catalyze specific chemical reactions.
substrates
Select all of the following cellular processes or reactions that are powered by ATP.
synthesis of large molecules muscle contraction moving chromosomes
Energy is defined as
the ability to do work or move matter.
Select all of the following that are examples of kinetic energy.
the movement of molecules a rolling cart light
The active site is the place on an enzyme where
the substrates bind
Highly organized organisms do not conflict with the principle that entropy always increases because
they use incoming energy to maintain organization.
True or false: Energy cannot be created or destroyed.
true
Plant cells are hypertonic compared to the surrounding soil. This helps to promote water movement into the cell, which generates
turgor pressure.
