Chapter 1

Question 1

archaeon

Answer 1

Microscopic organism that is a member of one of the
two divisions of prokaryotes; often found in hostile
environments such as hot springs or concentrated brine.
(See also bacterium.)

Question 2

bacterium

Answer 2

Microscopic organism that is a member of one of the two
divisions of prokaryotes; some species cause disease.
The term is sometimes used to refer to any prok
aryotic
microorganism, although the world of prokaryotes also
includes archaea, which are only distantly related to each
other. (See also archaeon.)

Question 3

cell

Answer 3

The basic unit from which a living organism is made; an
aqueous solution of chemicals, enclosed by a membrane,
that has an ability to self-replicate

Question 4

chloroplast

Answer 4

Specialized organelle in algae and plants that contains

chlorophyll and serves as the site for photosynthesis

Question 5

chromosome

Answer 5

Long, threadlike structure composed of DNA and proteins
that carries the genetic information of an organism;
becomes visible as a distinct entity when a plant or animal
cell prepares to divide

Question 6

cytoplasm

Answer 6

Contents of a cell that are contained within its plasma
membrane but, in the case of eukaryotic cells, outside the
nucleus.

Question 7

cytoskeleton

Answer 7

System of protein filaments in the cytoplasm of a eukaryotic
cell that gives the cell shape and the capacity for directed
movement. Its most abundant components are actin
filaments, microtubules, and intermediate filaments.

Question 8

cytosol

Answer 8

Contents of the main compartment of the cytoplasm,
excluding membrane-enclosed organelles such as
endoplasmic reticulum and mitochondria. The cell fraction
remaining after membranes, cytoskeletal components, and
other organelles have been removed

Question 9

DNA

Answer 9

Double-stranded polynucleotide formed from two separate
chains of covalently linked deoxyribonucleotide units.
It serves as the cell’s store of genetic information that is
transmitted from generation to generation.

Question 10

electron microscope

Answer 10

Instrument that illuminates a specimen using beams of
electrons to reveal and magnify the structures of very small
objects, such as organelles and large molecules

Question 11

endoplasmic reticulum

Answer 11

Labyrinthine membrane-enclosed
compartment in the cytoplasm of
eukaryotic cells where lipids and
proteins are made.

Question 12

eukaryote

Answer 12

An organism whose cells have a distinct nucleus and

cytoplasm.

Question 13

evolution

Answer 13

Process of gradual modification and adaptation that occurs

in living organisms over generations.

Question 14

fluorescence microscope

Answer 14

Instrument used to visualize a specimen that has been
labeled with a fluorescent dye; samples are illuminated
with a wavelength of light that excites the dye, causing it
to fluoresce.

Question 15

genome

Answer 15

The total genetic information carried by all the
chromosomes of a cell or organism; in humans, the total
number of nucleotide pairs in the 22 autosomes plus the X
and Y chromosomes

Question 16

golgi apparatus

Answer 16

Membrane-enclosed organelle in 
eukaryotic cells that modifies the 
proteins and lipids made in the 
endoplasmic reticulum and sorts 
them for transport to other sites.

Question 17

homologous

Answer 17

Describes genes, chromosomes, or any structures that are
similar because of their common evolutionary origin. Can
also refer to similarities between protein sequences or
nucleic acid sequences.

Question 18

micrometer

Answer 18

Unit of length equal to one millionth (10–6) of a meter or

10–4 centimeter

Question 19

microscope

Answer 19

Instrument for viewing extremely small objects. Some use a
focused beam of visible light and are used to examine cells
and organelles. Others use a beam of electrons and can be
used to examine objects as small as individual molecules.

Question 20

mitochondrion

Answer 20

Membrane-enclosed organelle, about the size of a
bacterium, that carries out oxidative phosphorylation and
produces most of the ATP in eukaryotic cells.

Question 21

model organism

Answer 21

A living thing selected for intensive study as a representative
of a large group of species. Examples include the mouse
(representing mammals), the yeast Saccharomyces cerevisiae
(representing a unicellular eukaryote), and Escherichia coli
(representing bacteria)

Question 22

nucleus

Answer 22

In biology, refers to the prominent, rounded structure that
contains the DNA of a eukaryotic cell. In chemistry, refers to
the dense, positively charged center of an atom.

Question 23

organelle

Answer 23

A discrete structure or subcompartment of a eukaryotic
cell that is specialized to carry out a particular function.
Examples include mitochondria and the Golgi apparatus.

Question 24

photosynthesis

Answer 24

The process by which plants, algae, and some bacteria
use the energy of sunlight to drive the synthesis of organic
molecules from carbon dioxide and water

Question 25

plasma membrane

Answer 25

The protein-containing lipid bilayer that surrounds a living
cell

Question 26

prokaryote

Answer 26

Major category of living cells distinguished by the absence
of a nucleus; includes the archaea and the eubacteria
(commonly called bacteria)

Question 27

protein

Answer 27

Macromolecule built from amino acids that provides cells
with their shape and structure and performs most of their
activities.

Question 28

protozoan

Answer 28

A free-living, nonphotosynthetic, single-celled, motile

eukaryote

Question 29

ribosome

Answer 29

Large macromolecular complex, composed of RNAs and
proteins, that translates a messenger RNA into a polypeptide
chain

Question 30

RNA

Answer 30

Molecule produced by the transcription of DNA; usually
single-stranded, it is a polynucleotide composed of
covalently linked ribonucleotide subunits. Serves a variety
of informational, structural, catalytic, and regulatory
functions in cells.