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50 terms

Test 4

Chapters 10 and 11
STUDY
PLAY
Which of the following is directly associated with photosystem one?
Receiving electrons from plastocyanin
Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light.
What did Engelmann conclude about the congregation of bacteria in red and blue areas?
Bacteria congregated in these areas because these areas had the most oxygen being released.
Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light.
An outcome of this experiment was to help determine
The relationship between wavelengths of light and oxygen released during photosynthesis.
Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light.
If you ran the same experiment without passing light through a prism, what would you predict?
The bacteria would be evenly distributed along the algal filaments.
What does the chemiosmotic process in chloroplasts involve?
Establishment of a proton gradient
What are the products of the light reactions that are absolutely subsequently used by the Calvin Cycle?
ATP and NADPH
Where does the Calvin cycle take place?
Stroma of the chloroplast
When oxygen is released as a result of photosynthesis, it is a by-product of
Splitting the oxygen molecules
Some photosynthetic organsims contain chloroplasts that lack photosystem II, yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be
To test the liberation of O2 in the light
Where are the molecules of the electron transport chain found in chloroplasts?
Thylakoid membrane
Which of the followin statements best describes the relationship between photosynthesis and respiration?
Photosynthesis stores energy in complex organic molecules, while respiration releases them.
P680+ is said to be the strongest biological oxidizing agent. Why?
This molecule results from the transfer of an electron to the primary electron acceptor of photosystem II and strongly attracts another electron.
The reaction-center chlorophyll of photosystem I is known as P700 because
This pigment is best at absorbing light with a wavelength of 700 nm
Which statement describes the functioning of photosytem II?
The electron vacancies in P680+ are filled by electrons derived from water.
Some photosynthetic bacteria (e.x. purple sulfur bacteria) have photosytem I but not II, while others (ex. cyanobacteria) have both PSI and PSII. Which of the following might this observation imply?
Photosystem I must be more ancestral.
Synthesis of ATP by the chemiosmotic mechanism occurs during
both photosynthesis and respiration
What is the primary function of the Clavin cycle?
Synthesize simple sugars from carbon dioxide.
THe pH of the inner thylakoid space has been measure, as have the pH of the stroma and of the cytosol of a particular plant cell. Which, if any, relationship would you expect to find?
The pH within the thylakoid is less than that of the stroma.
Why are C4 plants able to photosynthesize with no apparent photorespiration?
They use PEP carboxylase to initially fix CO2
CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they
fix CO2 into organic acids during the night
How is photosynthesis similar in C4 and CAM plants?
In both cases, CO2 is initially fixed into 4-carbon organic acids.
From the perspective of the cell receiving the message, the three stages of cell signaling are
signal reception, signal transduction, and cellular response
Testosterone functions inside a cell by
binding with a receptor protein that enters the nucleus and activates specific genes
Which is true of transcription factors?
They control which genes are expressed
A major group of G protein-linked receptors contain seven transmembrane alpha helices. The amino end of the protein lies at the exterior face of on the cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than others.
The coupled G protein most likely interacts with this receptor
at the loop between H5 and H6
One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, then activating relay proteins. Which type does this?
receptor tyrosine kinases
In general, a signal transmitted via phosphorylation of a series of proteins
brings about a conformational change to each protein
Which process is most directly driven by light energy?
transfer of electrons from chlorophyll molecules to the primary electron acceptor
Which of the following does not occur during the Calvin cycle?
release of oxygen
In mitochondria, protons are pumped from the matrix into the intermembrane space, whereas in chloroplasts
the stroma into the thylakoid space
In the yeast signal transcduction pathway, after both types of mating cells have released the mating factors and the factors have bound to specific receptors on the correct cells,
binding induces changes in the cells that lead to cell fusion
All of the following are true statements concerning biofilms EXCEPT:
Their susceptibility to antimicrobials is the same as if the microbe were alone.
Paracine signaling
involves secreting cells acting on nearby target cells by discharging a local regulator into extracellular fluid
At puberty, an adolescent female body changes in body structure and function of several organ systems, primarily under the influence of changing concentrations of estrogen and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects?
Estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its bindings.
Which of the following describes the events of apoptosis?
Its DNA and organelles become fragmented, the cell shrinks and forms blebs, and the cell self-digests.
The main proteases involved in apoptosis are
caspases
Binding of a signaling molecule to which type of receptor leads directly to a change in distribution of ions on the opposite sides of the membranes?
Ligand-gated ion channel
The activation of receptor tyrosine kinases is characterized by
dimerization and phosphorylation
Sutherland discovered that epinephrine
elevates the cytosolic concentrations of cyclic AMP
The general name for an enzyme that transfers phosphate groups from ATP to a protein is
protein kinase
Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently consumed coffee would have increased levels of
cAMP
Lipid-soluble signal molecules such as testosterone, cross the membranes of all cells but affect only target cells because
intracellular receptors are present only in target cells
A drug designed to inhibit response of cells to testosterone would almost certainly result in which of the following?
a decrease in transcriptal activity of certain genes
Apoptosis involves all of the following?
Lysis of the cell
Human caspases can be activated by
irreparable DNA damage or protein misfolding
An inhibitor of which of the following could be used to block the release of calcium from the endoplasmic reticulum?
phospholipase C
Which of the substances below is a protein that can hold several other relay proteins as it binds to an activated membrane receptor?
Scaffolding protein.
Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because
they amplify the original signal manyfold
Affinity chromatography is a method that can be used to purify cell-surface receptors, while they retain their hormone-binding ability. A ligand (hormone) for a receptor of interest is chemically linked to polystyrene beads. A solubilized preparation of membrane proteins is passed over a column containing these beads. Only the receptor binds to the beads.

When an excess of ligand is poured through the column after the receptor binding step. what do you expect will occur?
The ligand will cause the receptor to be displaced from the beads and eluted out.
Affinity chromatography is a method that can be used to purify cell-surface receptors, while they retain their hormone-binding ability. A ligand (hormone) for a receptor of interest is chemically linked to polystyrene beads. A solubilized preparation of membrane proteins is passed over a column containing these beads. Only the receptor binds to the beads.

This method of affinity chromatography would be expected to collect which of the following?
Molecules of purified receptor