BIS 2A questions
"Bond energy" is:
energy to pull two bonded atoms apart
The ingredients listed below will give you 2 ml of ½ molar sodium chloride after mixing. Which will release the greatest amount of energy (= has the largest negative ∆G) when doing so?
enough sodium metal and CL2 gas to produce the amount of sodium chloride salt described above, plus 2ml water
What's the difference between "steady state" and "equilibrium"?
equilibrium is an example of steady state, but not all steady states are at equilirium
Which molecule, if employed as an external electron source to build NADH, could donate the most electrons per mole of reductant? A reduction table is provided, if needed
glucose
The preceding example of burning jet fuel describes the loss of potential energy. What form does that energy take after the jet fuel is burned?
heat, moving, and light
When Prof. Britt says "harness energy" she means
using energy to do work
Which has higher potential energy (ability to do work)?
2 H molecules and 1 O molecule
Sort the following items in the order in which they occurred: Eukaryotes evolve Oceans present on Earth Collision of the Earth with the planetoid Theia Photosynthesis evolves Cyanobacteria evolve a pathway to oxidize water
3 2 4 5 1
Oxidation of glucose means:
loss of electrons from glucose oxidation of glucose
What happens to ATP when you "use" it?
ATP is converted into ADP which can be recycled back into ATP.
Oxidative Phosphorylation A metabolic pathway that (oxidizes or reduces) an energy-rich source to produce ATP from ADP. Electrons are transferred from electron (donors or acceptors) to compounds with a (weaker or stronger) reduction potential. As electrons move through an electron transport chain, ETC, the energy in the electron is used to pump across a membrane. The pumping of these molecules against their concentration gradient is a form of transport. The movement of these molecules back into the cell (down their concentration gradient) releases energy which the cell couples to the formation of . Photosynthesis Energy in is absorbed by an electron in a photocenter. This energy is converted from light energy into chemical energy into kenetic energy as the energized electron is used in back to back REDOX reaction in the electron transport chain, ETC. The ETC creates which is used by the cell to power the formation of ATP. In (cyclic or non-cylic) photosynthesis the electron returns to the photocenter. In (cyclic or non-cyclic) photosynthesis the electron reduces NADP+ to form .
Answer 1:oxidizes Answer 2:donors Answer 3:stronger Answer 4:protons Answer 5:active Answer 6:ATP Answer 7:light Answer 8:pmf Answer 9:cyclic Answer 10:non-cyclic Answer 11:NADPH
Write in the vocab term for each definition listed. Write your vocab terms in all lower case letters. A type of covalent bond where electrons are shared unequally: _______ The tendency of an atom to attract electrons towards itself: ______ A bond that forms between an electronegative atom and a hydrogen atom with a positive dipole: ___________ A type of covalent bond where electrons are shared equally: __________- A macromolecule that can exist as linear or cyclized, where it has a 1:2:1 ratio of carbon, hydrogen and oxygen: _________ A macromolecule that can exist as linear or cyclized, where it has a polar "head" group and a majority nonpolar "tail" group: _____ A bond that exists between two full, opposite charges: ________ A macromolecule that exists with a backbone where the functional groups are the amine and the carboxylic acid: _________ A macromolecule that contains a sugar, a phosphate group and a nitrogenous base: _________
Answer 1:polar covalent bond Answer 2:electronegativity Answer 3:hydrogen bond Answer 4:non polar covalent bond Answer 5:carbohydrate Answer 6:lipid Answer 7:ionic bond Answer 8:protein Answer 9:nucleic acid
Which of these bonds would you consider a polar covalent bond? Mark all that apply. C-O C-H C-C H-N H-O
C-O H-N H-O
Fill in the blanks below by pairing each of these macromolecules with its building block (lipid, carbohydrate, nucleotide or amino acid). (write your answers in all lower case letters)
CARBOHYDRATE -->Starch AMINO ACID-->protein NUCLEOTIDE-->nucleic acid LIPID-->triglyceride
In living things, the two major components of G, "Potential energy", are
Concentration and Molecular Structure
Which atoms would you consider more electronegative than carbon? Mark all that apply.
F O N
Which compounds can act as an electron donor for acetate? Group of answer choices
GLUCOSE, H2, NADH
In the reaction 2H2 + O2 -> 2H20, what is being oxidized?
H2
RuBisCo is considered to be an inefficient enzyme because:
It is unusually slow for an enzyme. It uses the wrong substrate ¼ of the time. It produces the wrong product ¼ of the time.
NADH and FADH₂ are produced during the citric acid cycle. Which electron donor, when it donates its electrons to the ETC, results in more protons?
NADH, because it donates electrons earlier in the ETC.
In fermentation of glucose in human cells, the terminal electron acceptor is pyruvate, forming lactate. In respiration of glucose in human cells, the terminal electron acceptor is _____, forming ____.
O2, water
What is one way in which the citric acid cycle (CCC) and the reverse citric acid cycle (RCCC) different from one another?
The CCC produces ATP (from GTP); the RCCC consumes ATP.
The concentration of methane in the Earth's atmosphere has changed radically during Earth's history-going up at first, and then down later. These changes were induced by the sequential evolution of two major innovations created by living, evolving prokaryotes. What were these?
The evolution of methanogenic respiration, then oxygenic photosynthesis.
Which of the following compartments would be expected to be most acidic when O₂ is available?
The intermembrane space.
In which compartment does water-splitting occur? in chloroplast AND Which compartment is most acidic when light is available?
The lumen of the thylakoids.
Oxidative phosphorylation of ATP is directly powered by:
The negative ∆G of protons moving down a gradient.
The leaves of green plants are green because:
The pigments in the leaves of green plants do not absorb green light as strongly as they absorb other visible light photons.
Why do photosynthetic organisms need to use up ATP molecules to form glucose from CO₂?
The reaction (CO₂ + NADPH → Glucose + NADP) is energetically unfavorable.
In thermodynamics, a living organism is an example of a...
open system
The Earth is an example of a...
open system, with meteors
what does OIL RIG mean?
oxidation is loss of electrons reduction is gain of electrons
A glucose molecule has a bond between O and C. This is a...
polar covalent bond
The reactant 6CO2 enters the plant from the atmosphere . The reactant energy enters the plant through from sunlight . The product C6H12O6 is metabolized by the plant in its mitochondria and is created through the [ Select ] ["oxidation", "reduction"] of CO2. The product 6O2 is considered a [ Select ] ["reactant for oxygenic photosynthesis", "waste product of oxygenic photosynthesis", "waste product of anoxygenic photosynthesis", "a reactant for anoxygenic photosynthesis"] .
reduction waste product of oxygenic photosynthesis
∆G˚' refers to the change in Gibbs free energy under (biological) standard conditions. These standard conditions include:
all chemical components (reactants and produces) are constantly at 1 Molar
What part of the statement below is incorrect? Rewrite the statement such that it displays the correct reasoning behind why nonpolar molecules do not dissolve in water. Think about the chemical interactions. (mark all that apply) Water molecules repel nonpolar substances away.
repel needs to be replaced with "do not attract" The corrected statement should read: Water molecules do not interact with nonpolar compounds, which become oriented away from water.
A chemical reaction occurs in a test tube in lab. During the reaction, "reactants" gradually become "products" until equilibrium is reached. At equilibrium: answer A: ∆G = 0 answer B: No more reactions occur: no molecules of reactant become product, and no molecules of product become reactant. Anaswer C: Some molecules of reactant become product, and some molecules of product become reactant. Both A and C are true Both B and C are true
both A and C are true
What's the difference between a photosystem (ie, PSI) and a photoreaction center (ie, P700)?
A photosystem contains many pigments and proteins, but only a subset of these pigments (the photoreaction center) can actually perform photochemistry- donating electrons to an ETC.
Autotrophs can: Fix carbon from CO₂. Capture high energy electrons from organic sources (food). Capture high energy electrons from inorganic sources. A and B only. A, B, and C.
A,B,C
The ETC leading to the formation of NADPH is:
More reducing (=lower reduction potential) than the ETC leading to the reduction of P700. More reducing than the ETC used to deliver electrons from NADH to an external electron acceptor.
The light reactions of photosynthesis produce NADPH in order to:
Reduce CO2
What is the external source of electrons used to build NADPH from NADP in green sulfur bacteria?
Reduced sulfur compounds, like H₂S.
The energy released during the transport of electrons from NADH to O₂ via the electron transport chain is directly harvested in the form of...
a proton gradient
An external electron source must be utilized to reduce environmental CO₂ and build sugars. In the Calvin cycle, the electrons used to fix CO₂ come from:
water
H2O is a liquid at room temperature while CO2 is a gas. Why is this?
water molecules are attracted to each other, CO2 molecules are not
