Bacterial production of the enzymes needed for the synthesis of the amino acid tryptophan declines with increasing levels of tryptophan and increases as tryptophan levels decline. This is an example of
Succinylcholine is structurally almost identical to acetylcholine, but if combined with the enzyme that normally hydrolyzes acetylcholine, the enzyme is no longer able to hydrolyze acetylcholine. This suggests that _____.
succinylcholine must be a competitive inhibitor of acetylcholine
form leakproof sheets of cells.
channels through which small molecules can move from cell to cell
link cells to each other; they form strong sheets of cells
Where do the electrons needed by photosystem II originate?
consume other plants or animals or decompose organic material
In eukaryotes, most of the high-energy electrons released from glucose by cell respiration _____.
reduce NAD+ to NADH, which then deliver them to the electron transport chain
The energy production per glucose molecule through the citric acid cycle is _____.
2 ATP, 6 NADH, 2 FADH2
NADH and FADH 2 are important in cellular respiration because they deliver high-energy electrons to the electron transport system. Electron transport produces _____ ATP molecule(s) per NADH molecule and _____ ATP molecules(s) per FADH 2 molecule.
three ... two
In electron transport, high-energy electrons "fall" to oxygen through a series of reactions. The energy released is used to _____.
then flow back out into the the inner compartment (matrix) of the mitochodria. On the way back, protons turn ATP synthase turbines and produce ATP.
The end products of the citric acid cycle include
FADH2. CO2. NADH. ATP.
In electron transfer (oxidative) phosphorylation, electrons are passed from one electron carrier to another. The energy released is used to _____.
pump protons (H+) across the mitochondrial membrane
In a eukaryotic cell, the electron transport chain is precisely located in or on the _____.
cristae (inner membrane) of the mitochondrion
Rotenone is a poison that blocks the electron transport chain. When it does so, glycolysis and the citric acid cycle eventually halt as well. This is because _____.
they run out of NAD+ and FAD
Which of the following directly requires molecular oxygen (O2)?
the electron transport chain
In muscle cells, fermentation produces _____.
lactate and NAD+
In fermentation _____ is reduced and _____ is oxidized.
pyruvate ... NADH
In the absence of oxygen, cells need a way to regenerate which compound?
Muscle tissues make lactic acid from pyruvate so that you can _____.
regenerate (oxidized) NAD+
In fermentation, ________ is ________.
NADH . . . oxidized
When a cell uses fatty acid for aerobic respiration, it first hydrolyzes fats to
glycerol and fatty acids.
To obtain energy from starch and glycogen, the body must begin by
hydrolyzing both starch and glycogen to glucose.
the cells of an ant and a horse are, on average, the same small size; a horse just has more of them. what is the main advantage of small cell size?
small cells can better take up sufficient nutrients and oxygen to service their cell volume
which statement correctly describes bound ribosomes
bound ribosomes generally synthesize membrane proteins and secretory proteins
In which cell would you find the most lysosomes?
white blood cell that engulf bacteria
In which cell would you find the most smooth ER?
ovarian cell that produces the steroid hormone estrogen
In which cell would you find the most rough ER?
Pancreatic cell that secretes digestive enzymes
In which cell would you find the most tight junctions?
cell in tissue layer lining digestive tract
which of the following structures is not directly involved in cell support or movement?
what four cellular components are shared by prokaryotic and eukaryotic cells?
DNA as genetic material, ribosomes, plasma membrane, and cytoplasm
in what ways do the internal membranes of a eukaryotic cell contribute to the functioning of the cell?
different conditions and conflicting processes can occur simultaneously within separate, membrane-enclosed compartments. Also, there is increased area for membrane-attached enzymes that carry out metabolic processes
explain how a protein inside the ER can be exported from the cell without ever crossing a membrane
A protein inside the ER is packaged inside transport vesicles that bud off the ER and then join to the Golgi apparatus. A transport vesicle containing the finished protein product then buds off the Golgi and travels to and joins with the plasma membrane, expelling the protein from the cell.
when the poison cyanide blocks the electron transport chain, glycolysis and the citric acid cycle soon grind to a half as well. why do you think they stop?
they run out of NAD+ and FAD
In glycolysis _____is oxidized and ____is reduced
glucose ; NAD+
in which of the following is the first molecule becoming reduced to the second molecule?
pyruvate -> lactate
which of the following is a true distinction between cellular respiration and fementation?
NADH is oxidized by the electron transport chain in respiration only.
how many turns of the Calvin cycle are required to produce one molecule of glucose?
During calvin cycle?
1) carbon fixation 2) oxidation of NADPH 3) consumption of ATP 4) regeneration of RuBP, the CO2 acceptor
why is it difficult for most plants to carry out photosynthesis in very hot, dry environments such as deserts?
the closing of stomata keeps CO2 from entering and O2 from leaving the plant
How is photosynthesis similar in C4 plants and CAM plants?
in both cases, rubisco is not used to fix carbon initially
The eukaryotic cell has multiple membrane-enclosed compartments. This evolutionary innovation provides what advantage to the cell?
The different membrane-enclosed spaces allow different parts of the cell to perform specific functions.
During cellular respiration, NADH
delivers its electron load to the first electron carrier molecule.
What purpose is directly served by chlorophyll a during photosynthesis?
It allows for the conversion of energy.
The energy used to produce ATP in the light reactions of photosynthesis comes from _____.