Which statement about extracellular structures (plant cell walls and the extracellular matrix of animal cells) is correct?
Information can be transmitted from these extracellular structures to the cytoplasm. (Extracellular structures provide mechanical and chemical signals that are transmitted across the plasma membrane to the interior of the cell.)
Which of the following functions is associated with the cytoskeleton in eukaryotic cells?
the beating of cilia or flagella
maintaining the position of the nucleus in the cell
the contraction of muscle cells in animals
determining the shape of animal cells
NOT:movement of RNA molecules from nucleus to cytoplasm
Which of the following correctly matches an organelle with its function?
central vacuole ... storage
A cell has formed a food vacuole as it ingested a food particle. Which of the following events is associated with the breakdown of that food particle?
Digestion of the food particle occurs in a vesicle enclosed by a membrane that separates the digestion from the cytoplasm.
(If the digestive enzymes were in the cytosol, they might degrade essential components of the cell.)
Which of the following clues would tell you if a cell is prokaryotic or eukaryotic?
whether or not the cell is partitioned by internal membranes (prokaryotic cells lack any internal membranous compartmentalization)
Which of the following are common traits of chloroplasts and mitochondria?
Mitochondria and chloroplasts contain their own DNA and ribosomes.
Mitochondria are found in _____.
both plant cells and animal cells. All eukaryotic cells, including plant and animal cells, contain mitochondria. NOT IN PRO
Which of these cell junctions form a barrier to the passage of materials?
Tight junctions; tight junctions form a barrier that prevents fluids from moving between cells
The primary role of ___ is to bind cells together.
desmosomes (anchoring junctions)
_____ aid in the coordination of the activities of adjacent animal cells.
Gap (communicating) junctions. Gap junctions allow for the passage of material between cells, thus facilitating communication between these cells.
cell cytoskeleton
a dynamic network of fibers that can be quickly dismantled and reassembled to change cell shape and the position of cell components.
Which structure-function pair is MATCHED?
nucleolus; production of ribosomal subunits
ribosome; protein synthesis
lysosome; intracellular digestion
golgi; protein trafficking
Cyanide binds to at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide will be found within the __________.
mitochondria
__ move lipids and proteins among the different organelles of the endomembrane system.
Small vesicles
Proteins that will be secreted from the cell are likely to be found in....
closed spaces bounded by membranes of the endomembrane system
Which structure is common to plant and animal cells?
mitochondrion
Which of the following is present in a prokaryotic cell?
ribosome
Which statement correctly describes the nuclear envelope of a eukaryotic cell?
The nuclear envelope is continuous with the endoplasmic reticulum.
All plant and animal cells carry out...
cellular respiration in mitochondria, producing ATP.
What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?
ER ? Golgi ? vesicles that fuse with plasma membrane
Which cell would be best for studying lysosomes?
phagocytic white blood cell, why????
Which structure is NOT part of the endomembrane system?
Golgi apparatus
nuclear envelope
plasma membrane
ER
chloroplast
chloroplast
Which structure is part of the endomembrane system?
Golgi apparatus
nuclear envelope
plasma membrane
ER
Scanning electron microscopy (SEM)
most widely used to study the surface detail of objects including preserved and specially prepared biological samples; best suited for studying surfaces.
Any type of electron microscopy requires...
that the cell be chemically fixed before it can be visualized; this fixation kills the cell.
transmission electron miscopy (TEM)
requires specimens to be sectioned, revealing only the cut edges of the cells; researchers are most likely to use it to study internal structure of cilia
light microscopy
can resolve individual cells and very limited details of organelles. The internal structure of cilia is beyond the limits of light microscopy.
Cell fractionation
used to separate different organelles to study their function separate from the rest of the cell
Which statement correctly describes an endomembrane function?
Products of the ER are usually modified during their transit from the cis to the trans region of the Golgi apparatus.(The cis and trans regions of the Golgi apparatus act as receiving and shipping departments. As molecules move from the cis to the trans f
Pancreatic cells, which secrete a large amount of digestive enzymes, are labeled with radioactive leucine and then chased for several hours with nonradioactive leucine. Photographic emulsions are prepared at different times during the chase. Where would t
Exterior of the cell (Black spots would appear on the exterior of the cell after 3 hours, indicating that the proteins had been secreted from the cell.)
What path does a protein in the secretory pathway take, starting from its site of synthesis?
Rough ER, Golgi apparatus, secretory vesicles, plasma membrane. Proteins are synthesized in the rough ER, modified in the Golgi apparatus, and carried in secretory vesicles to the plasma membrane, where they are secreted.
During a pulse-chase experiment, photographic emulsions were prepared at different times during the chase, and radioactive spots were detected at the following times and locations: 5 minutes: rough ER; 10 minutes: Golgi apparatus; 40 minutes: endosomes; 7
The final destination of the proteins was the lysosome (This conclusion can be drawn from the results, since the radioactive spots were last detected at the lysosome, which is not a secretory vesicle)
What scientific hypotheses can be tested by a pulse-chase experiment?
Movement of molecules through a cell over time
pulse-chase experiment
A type of experiment in which a population of cells or molecules at a particular moment in time is marked by means of a labeled molecule (pulse) and then their fate is followed over time (chase).
True or false? Proteins produced during the "chase" phase of a pulse-chase experiment are labeled with radioactive material.
false, during the chase phase, cells are provided with a large amount of nonradioactive material, so they are not labeled.
What is the first step in a pulse-chase experiment?
Incubating cells with a labeled molecule (cells are first "pulsed" with a large amount of labeled material for a short time)
The ___ contains most of a cell's DNA.
nucleus
where are ribosomal subunits made?
in the nucleolus