Chapter 9 Cellular Respiration and Fermentation Flashcards
Adenosine Triphosphate
A molecule consisting of adenine, a sugar, and three phosphate groups that can be hydrolyzed to release energy. Universally used by cells to store and transfer energy.
Adenosine diphosphate
A molecule consisting of adenine, a sugar, and two phosphate groups. Addition of a third phosphate group produces adenosine triphosphate (ATP).
Glucose
Six-carbon monosaccharide whose oxidation in cellular respiration is the major source of ATP in animal cells.
What is the most common fuel in organisms?
Glucose
Why does ATP make things happen in cells?
Because it has a great deal if potential energy
______________ energy in an electro is based on its position relative to other electrons and protons in the nuclei of nearby atoms.
Potential Energy
Exergonic
Referring to a chemical reaction that can occur spontaneously, releasing heat and/or increasing entropy, and for which the Gibbs free-energy change (ΔG) ≫ 0. Compare with endergonic.
Endergonic
Referring to a chemical reaction that requires an input of energy to occur and for which the Gibbs free-energy change (ΔG) ≫ 0. Compare with exergonic.
Why is the hydrolysis of ATP exergonic?
The entropy of the product molecules is much higher than that of the reactants and because there is a large drop in potential energy when ADP and Pi are formed from ATP.
Phosphorylation or phosphorylate
The addition of a phosphate group to a molecule.
Why is the phosphorylation of proteins exergonic?
The electrons in ADP and the phosphate group ave much less potential energy than they did in ATP.
Explain how ATP has high potential energy.
ATP’s high potential energy results, in part, from the four negative charges clustered in its three phosphate groups. The negative charges repel each other, raising the potential energy of the electrons.
How does protein move?
When proteins are phosphorylated or an ATP molecule binds to them, they often change shape in a way that alters their activity. (Phosphorylation changes the shape and activity of proteins.)
***Protein movement either in response to phosphorylation or to binding of an entire ATP molecule is what transport materials inside cells, power flagella or cilia, and pumps ions across membranes. It also drives endergonic reactions required for life.
Reduction-oxidation reactions or redox reactions
are a class of chemical reactions that involve the loss or gain of one or more electrons.
Why are redox reactions central?
because the drive the formation of ATP
In a redox reaction, the atom that loses one or more electrons is _________________.
Oxidized
In a redox reaction, the atom that gains an electron is __________________.
reduced
What does the mnemonic Oil Rig stand for?
Oxidation is lost; Reduction is gain
What does the mnemonic Leo the lion goes Ger mean?
Loss of electrons is oxidation; gain of electrons is reduction
What does the following statement mean?
Oxidation evens are always paired with a reduction.
A reactant that act as an electron donor is always associated with a reactant that acts as an electron acceptor. (if on atom loses an electron, another has to gain it)
In may redox reactions in biology, understanding whee oxidation and reduction have occurred becomes a matter of following _____________ atoms.
hydrogen
ex:
NAD+ is reduced to form NADH, NADH readily donates electrons to other molecule, as a result, it is know as an electron carrier
Which term describes the degree to which an element attracts electrons?
Reduction.
Polarity.
Oxidation.
Electronegativity.
Electronegativity is the tendency of an atom to attract electrons toward itself
Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other?
Polar and nonpolar.
Ionic and covalent.
Proton and electron.
Anion and cation.
Anion and cation. Each atom will carry a charge from the transfer of electrons.
Which of the following statements is true of the bonds in a water molecule?
The electron in each hydrogen atom is completely transferred to the oxygen atom, and each hydrogen atom has a net charge of +1.
Oxygen acts as the electron acceptor and is oxidized.
Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
There is equal sharing of the electrons between the oxygen atom and the two hydrogen atoms, and the net charge is zero.
Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
Correct. The oxygen and hydrogen atoms in water have partial charges, but the molecule has a net charge of zero.
Which of the following statements is not true of most cellular redox reactions?
The electron acceptor is reduced.
A hydrogen atom is transferred to the atom that loses an electron.
The reactant that is oxidized loses electrons.
Changes in potential energy can be released as heat.
Your Answer:
A hydrogen atom is transferred to the atom that loses an electron.
Correct. A hydrogen atom (proton, or H+) is often transferred to the atom that gains an electron.
What kind of bond is formed when lithium and fluorine combine to form lithium fluoride?
Ionic.
Redox.
Polar covalent.
Nonpolar covalent.
Your Answer:
Ionic.
Correct. The complete transfer of an electron from lithium to fluorine results in a stable compound in which both atoms have full outermost shells
Gaseous hydrogen burns in the presence of oxygen to form water:
2H2 + O2 → 2H2 O + energy
Which molecule is oxidized and what kind of bond is formed?
Oxygen, polar.
Oxygen, nonpolar.
Hydrogen, polar.
Hydrogen, nonpolar.
Your Answer:
Hydrogen, polar.
Correct. Hydrogen loses electrons to oxygen, which is more electronegative and thus pulls the electrons closer to itself.
A reduction-oxidation (redox) reaction always involves two events:
one substance loses
electrons and is said to be oxidized, while another substance gains electrons and is said to
be reduced.
Sodium chloride, or table salt, offers an example of atoms that have undergone oxidation and reduction to become ions. When sodium and chlorine react to form sodium chloride, one electron is completely transferred from the sodium atom to the chlorine atom.
What it the result?
The result is a sodium cation and a chloride anion.
In this redox reaction, the sodium atom lost an electron—it was oxidized.
The new sodium ion is a positively charged cation. The chlorine atom gained an electron—it was reduced.
The new chloride ion is a negatively charged anion.
In redox reactions, electrons can be transferred completely from one molecule or atom to
another, forming an __________________ bond, or they can simply shift positions in ____________________bonds.
ionic;covalent
When electrons are shared equally, the bonds are _______________________
nonpolar
In carbon dioxide, the nucleus of the carbon atom holds the electrons less tightly. Carbon
has been __________________ electrons. In water, the nucleus of the oxygen atom holds the
electrons more tightly. Oxygen has been _______________________ electrons.
oxidized—it “lost”
reduced—it “gained”
Because the atomic nuclei of the product molecules hold the electrons more tightly than they were held in the reactant molecules, the products have___________________. Such reactions tend to be spontaneous, or ________________, and release free energy.
lower potential energy
exergonic
Anion
An ion with a negative electrical charge as a result of having gained electrons.
cation
An ion with a positive electrical charge as a result of having lost electrons.
covalent bond
A bond in which electrons are shared between atoms or molecules.
exergonic
Producing heat or energy. An exergonic reaction is spontaneous and occurs
when the products have lower potential energy than the reactants.
ion
An electrically charged atom or molecule.
ionic bond
A bond in which electrons are completely transferred from one atom or molecule
to another.
nonpolar bond
A symmetric bond that results when electrons are shared equally.
oxidation
The loss of electrons during a redox reaction.
polar bond
An asymmetric bond that results when electrons are transferred in ionic bonding
or when electrons are shared unequally in covalent bonding.
potential energy
potential energy The energy stored in matter through its position or its shape.
The gain of electrons during a redox reaction.
reduction
A class of chemical reactions that involves the loss and gain of electrons.
reduction-oxidation (redox) reaction
nonpolar bond
A symmetric bond that results when electrons are shared equally.
oxidation
The loss of electrons during a redox reaction.
polar bond
An asymmetric bond that results when electrons are transferred in ionic bonding
or when electrons are shared unequally in covalent bonding.
potential energy
potential energy The energy stored in matter through its position or its shape.
The gain of electrons during a redox reaction.
reduction
A class of chemical reactions that involves the loss and gain of electrons.
reduction-oxidation (redox) reaction
When glucose burns, the change in potential energy is converted to ______________.
kinetic energy in the form of heat
In cells, the change in free energy that occurs during the oxidation of glucose is used to synthesize ______________ from _____________ and __________.
ATP, ADP, Pi
