Biology Test 3

When biologists wish to study the internal ultrastructure of cells, they can achieve the finest resolution by using
a transmission electronic microscope.
The advantage of light microscopy over electron microscopy is that
light microscopy allows one to view dynamic processes in living cells.
A primary objective of cell fractionation is to
separate the major organelles so that their particular functions can be determined
In the fractionation of homogenized cells using centrifugation, the primary factor that determines whether a specific cellular component ends up in the supernatant or the pellet is
the size and weight of the component. `
What is the reason that a modern electron microscope (TEM) can resolve biological images to the subnanometer level, as opposed to tens of nanometers achievable for the best super-resolution light microscope?
Electron beams have much shorter wavelengths than visible light.
All of the following are part of a prokaryotic cell except
an endoplasmic reticulum.
What is the function of the nucleus?
It houses DNA.
Mitosis refers to _____.
producing new cells
What is the function of the cell membrane?
take in and release materials
Which of the following is most important to transport within a cell?
microtubules and intracellular membranes
When do cells take on their unique characteristics?
during embryonic development
Which of the following is a major cause of the size limits for certain types of cells?
the need for a surface area of sufficient area to support the cell's metabolic needs
The evolution of eukaryotic cells most likely involved
endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria
Prokaryotes are classified as belonging to two different domains. What are the domains?
Bacteria and Archaea
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
In eukaryotic cells the first step in protein synthesis is the _____.
transferring of information from DNA to messenger RNA
A cell with a predominance of free ribosomes is most likely
producing primarily cytoplasmic proteins.
Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids?
smooth endoplasmic reticulum
Which structure is the site of the synthesis of proteins that may be exported from the cell?
rough ER
Hydrolytic enzymes must be segregated and packaged to prevent general destruction of cellular components. Which of the following organelles contains these hydrolytic enzymes in animal cells?
The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells?
smooth ER
Which of the following produces and modifies polysaccharides that will be secreted?
Golgi apparatus
Which organelle often takes up much of the volume of a plant cell?
Which organelle is the primary site of ATP synthesis in eukaryotic cells?
In a plant cell, DNA may be found
in the nucleus, mitochondria, and chloroplasts.
Why isn't the mitochondrion classified as part of the endomembrane system?
Its structure is not derived from the ER or Golgi.
In a liver cell detoxifying alcohol and some other poisons, the enzymes of the peroxisome remove hydrogen from these molecules and
transfer the hydrogen to oxygen molecules to generate hydrogen peroxide.
How does the cell multiply its peroxisomes?
They split in two after they become sufficiently large.
Movement of vesicles within the cell depends on what cellular structures?
microtubules and motor proteins
The smallest cell structure that would most likely be visible with a standard (not super-resolution) research-grade light microscope is
a mitochondrion.