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?
A) DNA
B) Cell
C) Organelle
D) Protein
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The Paramecium is a multicellular microorganism covered with hairlike cilia.
A) True
B) False
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Cells of different types can have different chemical requirements.
A) True
B) False
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The branch like extensions that sprout from a single nerve cell in a mammalian brain can extend over several hundred micrometers.
A) True
B) False
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The flow of genetic information is controlled by a series of biochemical reactions that result in the production of proteins, each with its own specific order of amino acids. Choose the correct series of biochemical reactions from the options presented here.
A) Replication, Transcription, Translation
B) Replication, Translation, Transcription
C) Translation, Transcription, Replication
D) Translation, Replication, Transcription
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Proteins are important architectural and catalytic components within the cell, helping to determine its chemistry, its shape, and its ability to respond to changes in the environment. Remarkably, all of the different proteins in a cell are made from the same 20 __________. By linking them in different sequences, the cell can make protein molecules with different conformations and surface chemistries, and therefore different functions.
A) Nucleotides
B) Sugars
C) Amino Acids
D) Fatty Acids
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Which statement is NOT true about mutations?
A) A mutation is a change in the DNA that can generate offspring less fit for survival than their parents.
B) A mutation can be a result of imperfect DNA duplication.
C) A mutation is a result of sexual reproduction.
D) A mutation is a change in the DNA that can generate offspring that are as fit for survival as their parents are.
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Changes in DNA sequence from one generation to the next may result in
offspring that are altered in fitness compared with their parents. The
process of change and selection
over the course of many
generations is the basis of __________.
A) mutation.
B) evolution.
C) heredity.
D) reproduction.
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Select the option that best finishes the following statement: “Evolution is a process __________.”
A) that can be understood based on the principles of mutation and selection.
B) that results from repeated cycles of adaptation over billions of years.
C) by which all present-day cells arose from 4–5 different ancestral cells.
D) that requires hundreds of thousands of years.
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Select the option that correctly finishes the following statement: “A cell’s genome _________________.”
A) is defined as all the genes being used to make protein.
B) contains all of a cell’s DNA.
C) constantly changes, depending upon the cell’s environment.
D) is altered during embryonic development.
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Which statement is NOT true about the events/conclusions from studies during the mid-1800s surrounding the discovery of cells?
A) Cells came to be known as the smallest universal building block of living organisms.
B) Scientists came to the conclusion that new cells can form
spontaneously from the
remnants of ruptured cells.
C) Light microscopy was essential in demonstrating the commonalities between plant and animal tissues.
D) New cells arise from the growth and division of previously existing cells.
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What unit of length would you generally use to measure a typical plant or animal cell?
A) centimeters
B) nanometers
C) millimeters
D) micrometers
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What 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.
A) Confocal
B) Transmission electron
C) Fluorescence
D) Phase-contrast
E) Scanning electron
F) bright-field
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What employs a light microscope and requires that samples be fixed and stained in order to reveal cellular details.
A) Confocal
B) Transmission electron
C) Fluorescence
D) Phase-contrast
E) Scanning electron
F) bright-field
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What 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.
A) Confocal
B) Transmission electron
C) Fluorescence
D) Phase-contrast
E) Scanning electron
F) bright-field
...
What 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.
A) Confocal
B) Transmission electron
C) Fluorescence
D) Phase-contrast
E) Scanning electron
F) bright-field
...
What has the ability to resolve cellular components as small as 2 nm.
A) Confocal
B) Transmission electron
C) Fluorescence
D) Phase-contrast
E) Scanning electron
F) bright-field
...
What requires coating the sample with a thin layer of a heavy metal to produce three-dimensional images of the surface of a sample.
A) Confocal
B) Transmission electron
C) Fluorescence
D) Phase-contrast
E) Scanning electron
F) bright-field
...
The nucleus of an animal cell is round, small, and difficult to distinguish using light microscopy.
A) True
B) False
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The presence of the plasma membrane can be inferred by the well-defined boundary of the cell.
A) True
B) False
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The cytosol is fairly empty, containing a limited number of organelles, which allows room for rapid movement via diffusion.
A) True
B) False
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Cell biologists employ targeted fluorescent dyes or modified fluorescent proteins in both standard fluorescence microscopy and confocal microscopy to observe specific details in the cell. Even though fluorescence permits better visualization, the resolving power is essentially the same as that of a standard light microscope because the resolving power of a microscope is limited by the __________ of light.
A) absorption
B) intensity
C) filtering
D) wavelength
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What is the smallest distance two points can be separated and still resolved using light microscopy?
A) 20 nm
B) 0.2 μm
C) 2 μm
D) 200 μm
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By definition, prokaryotic cells do not possess __________.
A) a nucleus.
B) replication machinery.
C) ribosomes.
D) membrane bilayers.
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Although there are many distinct prokaryotic species, most have a small range of shapes, sizes, and growth rates. Which of the following characteristics are not observed in prokaryotes?
A) a highly structured cytoplasm
B) endoplasmic reticulum
C) the ability to divide rapidly
D) a cell wall
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The terms “prokaryote” and “bacterium” are synonyms.
A) True
B) False
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Prokaryotes can adopt several different basic shapes, including spherical, rod-shaped, and spiral.
A) True
B) False
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Some prokaryotes have cell walls surrounding the plasma membrane.
A) True
B) False
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Prokaryotic cells are able to evolve very fast, which helps them to rapidly adapt to new food sources and develop resistance to antibiotics. Which of the options below lists the three main characteristics that support the rapid evolution of prokaryotic populations?
A) microscopic, motile, anaerobic
B) aerobic, motile, rapid growth
C) no organelles, cell wall, can exchange DNA
D) large population, rapid growth, can exchange DNA
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Oxygen is toxic to certain prokaryotic organisms.
A) True
B) False
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Mitochondria are thought to have evolved from anaerobic bacteria.
A) True
B) False
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Photosynthetic bacteria contain chloroplasts.
A) True
B) False
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Some prokaryotes can live by utilizing entirely inorganic materials. Which of the following inorganic molecules would you predict to be the predominant building block for fats, sugars, and proteins?
A) O 2
B) N 2
C) CO 2
D) H
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The __________ __________ is made up of two concentric membranes and is continuous with the membrane of the endoplasmic reticulum.
A) plasma membrane
B) Golgi network
C) mitochondrial membrane
D) nuclear envelope
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The nucleus, an organelle found in eukaryotic cells, confines the __________, keeping them separated from other components of the cell.
A) lysosomes
B) chromosomes
C) peroxisomes
D) ribosomes
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Which of the following organelles has both an outer and an inner membrane?
A) endoplasmic reticulum
B) mitochondrion
D) lysosome
D) peroxisome
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Mitochondria perform cellular respiration, a process that uses oxygen, generates carbon dioxide, and produces chemical energy for the cell. Which answer below indicates a correct pairing of material “burned” and the form of energy produced during cellular respiration?
A) fat, ADP
B) sugar, fat
C) sugar, ATP
D) fat, protein
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Mitochondria contain their own genome, are able to duplicate, and
actually divide on a
different timeline from the rest of the
cell. Nevertheless, mitochondria cannot function for long when
isolated from the cell because they are __________________.
A) viruses.
B) parasites.
C) endosymbionts.
D) anaerobes.
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The mitochondrial proteins found in the inner membrane are involved in the conversion of ADP to ATP, a source of energy for the cell. This process consumes which of the following substances?
A) oxygen
B) nitrogen
C) sulfur
D) carbon dioxide
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With respect to cellular respiration, the only organelles used by animal cells are mitochondria, while plant cells use both mitochondria and chloroplasts.
A) True
B) False
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The number of mitochondria inside a cell remains constant over the life of the cell.
A) True
B) False
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