Chapter 1 Review Flashcards
All living cells…
share the same basic chemistry.
Compared to eukaryotes, prokaryotic organisms are ____ abundant and ____ widespread on Earth.
more; more
Mistakes in replicating the DNA of a cell before division can have what type of effects?
positive, negative, or neutral
Which of the following microscopy techniques would allow the most detailed image showing the 3-D structure of a flagellum?
scanning electron microscopy
Living systems are incredibly diverse in size, shape, environment, and behavior. It is estimated that there are between 10 million and 100 million different species. Despite this wide variety of organisms, it remains difficult to define what it means to say something is alive. Which of the following can be described as the smallest living unit?
cell
One piece of evidence indicating that chloroplasts evolved from engulfed photosynthetic bacteria is
that they contain their own DNA.
The defining property that differentiates prokaryotic cells from eukaryotic cells is their
lack of a nucleus.
Self-replication of living cells occurs through the catalytic action of
proteins
uses a light microscope with an optical component to take advantage of the different refractive indices of light passing through different regions of the cell.
phase-contrast
employs a light microscope and requires that samples be fixed and stained in order to reveal cellular details.
bright-field
requires the use of two sets of filters. The first filter narrows the wavelength range that reaches the specimen and the second blocks out all wavelengths that pass back up to the eyepiece except for those emitted by the dye in the sample.
fluorescence
scans the specimen with a focused laser beam to obtain a series of two-dimensional optical sections, which can be used to reconstruct an image of the specimen in three dimensions. The laser excites a fluorescent dye molecule, and the emitted light from each illuminated point is captured through a pinhole and recorded by a detector.
confocal
has the ability to resolve cellular components as small as 2 nm.
transmission electron
requires coating the sample with a thin layer of a heavy metal to produce three-dimensional images of the surface of a sample.
scanning electron
The level of protein structure involves the interaction of more than one polypeptide chain into a three-dimensional structure.
Quaternary
The rate of a reaction depends on
the activation energy
The type of interaction stabilizes the alpha α- helix and the beta β-sheet structures of proteins
hydrogen bonds
A covalent bond is likely to be polar when
one of the atoms sharing electrons is much more electronegative than the other atom.
The variations in the physical characteristics between different proteins are influenced by the overall amino acid compositions, but even more important is the unique amino acid __________________ .
sequence
Disulfide bonds stabilize protein shape outside the cell by
covalent bonds between cysteines.
Which method is used for separating proteins based on specific interactions with other molecules?
affinity chromatography
The correct folding of proteins is necessary to maintain healthy cells and tissues. Unfolded proteins are responsible for such neurodegenerative disorders as Alzheimer’s disease, Huntington’s disease, and Creutzfeldt–Jakob disease (the specific faulty protein is different for each disease). What is the ultimate fate of these disease-causing, unfolded proteins?
They form protein aggregates.
Proteins bind selectively to small-molecule targets called ligands. The selection of one ligand out of a mixture of possible ligands depends on the number of weak, noncovalent interactions in the protein’s ligand-binding site. Where is the binding site typically located in the protein structure?
inside a cavity on the protein surface
Polypeptides are synthesized from amino acid building blocks. The condensation reaction between the growing polypeptide chain and the next amino acid to be added involves the loss of ________________.
a water molecule.
