Lecture 6

Question 1

cell wall

Answer 1

Protective layer in plant cells

Question 2

centriole

Answer 2

A structure in the
centrosome of an animal cell composed of a
cylinder of microtubule triplets arranged in
a 9 + 0 pattern. A centrosome has a pair of
centrioles.

Question 3

centrosome

Answer 3

A structure present
in the cytoplasm of animal cells that
functions as a microtubule-organizing center
and is important during cell division. A
centrosome has two centrioles.

Question 4

chloroplast

Answer 4

An organelle
found in plants and photosynthetic protists
that absorbs sunlight and uses it to drive the
synthesis of organic compounds from carbon
dioxide and water.

Question 5

chromosome

Answer 5

A cellular
structure consisting of one DNA molecule
and associated protein molecules. (In some
contexts, such as genome sequencing, the
term may refer to the DNA alone.) A eukaryotic
cell typically has multiple, linear
chromosomes, which are located in the nucleus.
A prokaryotic cell often has a single,
circular chromosome, which is found in the
nucleoid, a region that is not enclosed by a
membrane.

Question 6

cilia

Answer 6

Tiny hairs that aid in movement.

Question 7

cytoplasm/cytosol

Answer 7

The contents of
the cell enclosed by the plasma membrane;
in eukaryotes, the portion exclusive of the
nucleus.

Question 8

cytoskeleton

Answer 8

A network of microtubules,
microfilaments, and intermediate filaments
that extends throughout the cytoplasm and
serves a variety of mechanical, transport,
and signaling functions.

Question 9

desmosome

Answer 9

A type of intercellular junction
in animal cells that functions as a rivet, fastening
cells together.

Question 10

endoplasmic reticulum

Answer 10

An extensive
membranous network in eukaryotic cells,
continuous with the outer nuclear membrane
and composed of ribosome-studded
(rough) and ribosome-free (smooth)
regions.

Question 11

extracellular matrix

Answer 11

(ECM) The meshwork
surrounding animal cells, consisting of glycoproteins,
polysaccharides, and proteoglycans
synthesized and secreted by the cells.

Question 12

flagellum

Answer 12

A long cellular appendage specialized for locomotion.
Like motile cilia, eukaryotic flagella
have a core with nine outer doublet microtubules
and two inner single microtubules
(the ?9 + 2? arrangement) ensheathed in
an extension of the plasma membrane. Prokaryotic
flagella have a different structure.

Question 13

gap junction

Answer 13

A type of intercellular junction
in animal cells, consisting of proteins surrounding
a pore that allows the passage of
materials between cells.

Question 14

glycoprotein

Answer 14

A protein with one or more covalently

attached carbohydrates.

Question 15

golgi apparatus

Answer 15

An organelle in
eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and
route products of the endoplasmic reticulum
and synthesize some products, notably
noncellulose carbohydrates.

Question 16

intermediate filament

Answer 16

A component of the
cytoskeleton that includes filaments intermediate
in size between microtubules and
microfilaments.

Question 17

light microcope

Answer 17

An optical instrument
with lenses that refract (bend) visible
light to magnify images of specimens.

Question 18

lysosome

Answer 18

A membraneenclosed
sac of hydrolytic enzymes found
in the cytoplasm of animal cells and some
protists.

Question 19

microfilament

Answer 19

A cable composed of actin
proteins in the cytoplasm of almost every
eukaryotic cell, making up part of the cytoskeleton
and acting alone or with myosin
to cause cell contraction; also known as an
actin filament.

Question 20

microtubule

Answer 20

A hollow rod composed of
tubulin proteins that makes up part of the
cytoskeleton in all eukaryotic cells and is
found in cilia and flagella.

Question 21

mitochondria

Answer 21

An organelle in
eukaryotic cells that serves as the site of
cellular respiration; uses oxygen to break
down organic molecules and synthesize
ATP

Question 22

nuclear lamina

Answer 22

A netlike array of protein
filaments that lines the inner surface of the
nuclear envelope and helps maintain the
shape of the nucleus.

Question 23

nucleolus

Answer 23

A specialized structure in the nucleus consisting
of chromosomal regions containing
ribosomal RNA (rRNA) genes along with
ribosomal proteins imported from the cytoplasm;
site of rRNA synthesis and ribosomal
subunit assembly. See also ribosome.

Question 24

nucleus

Answer 24

An atom?s central core, containing
protons and neutrons. (2) The organelle of a
eukaryotic cell that contains the genetic mainvadersterial in the form of chromosomes, made up
of chromatin. (3) A cluster of neurons.

Question 25

organelle

Answer 25

Any of several kinds of membrane-enclosed structures with specialized functions, suspended in the cytosol of eukaryotic cells.

Question 26

peroxisome

Answer 26

An organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen (O2), producing and then degrading hydrogen peroxide (H2O2).

Question 27

plasma membrane

Answer 27

The membrane at the boundary of every cell that acts as a selective barrier, regulating the cell?s chemical composition.

Question 28

plasmodesmata

Answer 28

An open channel through the cell wall that connects the cytoplasm of adjacent plant cells, allowing water, small solutes, and some larger molecules to pass between the cells.

Question 29

prokaryotic cell

Answer 29

A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with prokaryotic cells (bacteria and archaea) are called prokaryotes.

Question 30

ribosome

Answer 30

A complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm; consists of a large subunit and a small subunit. In eukaryotic cells, each subunit is assembled in the nucleolus. See also nucleolus

Question 31

rough ER

Answer 31

That portion of the endoplasmic | reticulum with ribosomes attached.

Question 32

smooth ER

Answer 32

That portion of the endoplasmic | reticulum that is free of ribosomes.

Question 33

tight junction

Answer 33

A type of intercellular junction between animal cells that prevents the leakage of material through the space between cells.

Question 34

vacuole

Answer 34

A membrane-bounded vesicle whose specialized function varies in different kinds of cells.

Question 35

vesicle

Answer 35

A membranous sac in the | cytoplasm of a eukaryotic cell.