Lecture 6 Flashcards Preview

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Flashcards in Lecture 6 Deck (35):
1

cell wall

Protective layer in plant cells

2

centriole

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.

3

centrosome

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.

4

chloroplast

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.

5

chromosome

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.

6

cilia

Tiny hairs that aid in movement.

7

cytoplasm/cytosol

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

8

cytoskeleton

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

9

desmosome

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

10

endoplasmic reticulum

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

11

extracellular matrix

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

12

flagellum

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.

13

gap junction

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

14

glycoprotein

A protein with one or more covalently
attached carbohydrates.

15

golgi apparatus

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.

16

intermediate filament

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

17

light microcope

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

18

lysosome

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

19

microfilament

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.

20

microtubule

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.

21

mitochondria

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

22

nuclear lamina

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

23

nucleolus

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.

24

nucleus

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.

25

organelle

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

26

peroxisome

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

27

plasma membrane

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

28

plasmodesmata

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.

29

prokaryotic cell

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

30

ribosome

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

31

rough ER

That portion of the endoplasmic
reticulum with ribosomes attached.

32

smooth ER

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

33

tight junction

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

34

vacuole

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

35

vesicle

A membranous sac in the
cytoplasm of a eukaryotic cell.