The Living cell

Question 1

cell

Answer 1

the smallest membrane-bounded unit capable of independent reproduction

Question 2

cell wall

Answer 2

: a structural layer outside the plasma membrane, providing mechanical
strength. Typically present in bacteria, fungi and plants, but not animals.

Question 3

centromere

Answer 3

: the point at which a chromosome is attached to the spindle apparatus
during cell division

Question 4

centrosome

Answer 4

: an organising centre for microtubules that acts as the spindle pole
during mitosis

Question 5

chloroplast

Answer 5

: chlorophyll-containing organelle of plant cells, the site of photosynthesis

Question 6

chromatin

Answer 6

: a complex of DNA and proteins, the nucleoprotein material of
chromosomes

Question 7

chromosome

Answer 7

: a single large DNA molecule associated with protein in the nucleus of
eucaryotic cells. Sometimes used to refer to the DNA molecules of bacteria,
mitochondria and chloroplasts

Question 8

cilium (pl. cilia)

Answer 8

: a hair-like locomotor organelle of eucaryotic cells, containing a core
of microtubules. Similar to a flagellum but shorter, more numerous and with a
different type of beat

Question 9

cisterna (pl. cisternae)

Answer 9

Membrane-bound compartment, usually flattened, as in the

Golgi body or endoplasmic reticulum

Question 10

crista (pl. cristae)

Answer 10

: infolding of the inner membrane of the mitochondria

Question 11

cytoplasm

Answer 11

: the contents of the cell outside the nucleus

Question 12

cytoskeleton

Answer 12

: structural framework of the cytoplasm of eucaryotic cells, composed of
microtubules, microfilaments and intermediate filaments

Question 13

cytosol

Answer 13

: the soluble phase of the cytoplasm

Question 14

endoplasmic reticulum (ER)

Answer 14

: a system of membranes present in the cytoplasm of
eucaryotes. May have ribosomes bound on the cytoplasmic face to produce rough
ER

Question 15

eucaryotic

Answer 15

: pertaining to cells with a nucleus and complex cytoplasmic organelles (cf.
procaryotic)

Question 16

flagellum (pl. flagella)

Answer 16

): whip-like locomotor organelle for propulsion. Procaryotic and
eucaryotic flagella are different in structure and mechanism of action. Eucaryotic
flagella contain central microtubules

Question 17

glyoxysome

Answer 17

: single membrane bound organelle containing enzymes of the glyoxylate
cycle

Question 18

Golgi apparatus (or Golgi body)

Answer 18

: stacks of flattened membrane sacs and associated
vesicles concerned with the synthesis, packaging and targeting of proteins and
polysaccharides to other parts of the cell or for export from the cell

Question 19

granum (pl. grana)

Answer 19

: stack of appressed thylakoid membranes in chloroplasts

Question 20

)intermediate filament

Answer 20

: fibrous protein filaments about 10 nm in diameter forming part
of the cytoskeleton in eucaryotic cells

Question 21

lumen

Answer 21

: space inside a membrane system. A widely used term for the inside of the
endoplasmic reticulum and the thylakoid membrane

Question 22

lysosome

Answer 22

: a eucaryotic organelle with a single membrane containing hydrolytic
enzymes. The contents of the lumen are acidic

Question 23

membrane

Answer 23

: protein-containing lipid-bilayer structure acting as a permeability barrier
between different aqueous compartments

Question 24

microfilament

Answer 24

: cytoplasmic fibres made of actin, 5-9 nm in diameter, involved in
motility and cell structure, part of the cytoskeleton

Question 25

microsomes

Answer 25

: a vesicular membrane preparation of the endoplasmic reticulum produced by homogenization and centrifugation

Question 26

microtubule

Answer 26

: tubular structures, 25 nm in diameter, made of tubulin, found in eucaryotic cells and involved in motility and cell structure, part of the cytoskeleton

Question 27

mitochondrion (pl. mitochondria)

Answer 27

: a eucaryotic organelle bounded by two | membranes involved in cellular energy production

Question 28

nuclear envelope

Answer 28

: a double-membrane structure enclosing the nucleus

Question 29

nuclear pore

Answer 29

: circular opening in the nuclear envelope formed by the fusion of the inner and outer envelope membranes

Question 30

nucleolus

Answer 30

: granular structure in the nucleus, associated with specific chromosomes, involved in ribosome synthesis and assembly

Question 31

nucleosome

Answer 31

: bead-like structure of DNA wrapped round an octamer of histones, the repeating subunit of chromatin structure

Question 32

nucleus

Answer 32

: eucaryotic organelle containing the chromosomes, bounded by the nuclear envelope

Question 33

organelle

Answer 33

``` : a discrete microscopically visible structure in a cell, specialised for a particular function (eg nucleus, mitochondrion, chloroplast) ```

Question 34

periplasmic space

Answer 34

: the space between the inner and outer membranes of Gramnegative bacteria

Question 35

peroxisome

Answer 35

: single membrane bound organelle involved in reactions producing or consuming hydrogen peroxide

Question 36

pilus (pl. pili)

Answer 36

: hair-like structures on procaryotic organisms, involved in bacterial recognition and conjugation

Question 37

plasma membrane

Answer 37

: the membrane bounding a cell, also called plasmalemma or cell membrane

Question 38

plastid

Answer 38

: double membrane-bounded organelle in plant cells, including chloroplasts

Question 39

procaryotic

Answer 39

: pertaining to a cellular organism lacking a membrane-bounded nucleus, eg mycoplasma, bacteria, (cf. eucaryotic)

Question 40

protist

Answer 40

: single celled eucaryotic organismprotist, including the groups also called protozoa and unicellular algae

Question 41

ribosome

Answer 41

: RNA-protein structure, the site of protein synthesis in eucaryotic and procaryotic cells. Also present in mitochondria and plastid

Question 42

spindle apparatus

Answer 42

: microtubular structure for the alignment and movement of | chromosomes during cell division in eucaryotic cells

Question 43

stroma

Answer 43

: the soluble phase of the chloroplast, bounded by the chloroplast envelope. Site of the enzymes of CO2 fixation

Question 44

thylakoid

Answer 44

: closed membrane system of chloroplasts containing the photosynthetic energy transduction system. Also found in cyanobacteria, photosynthetic procaryotes

Question 45

turgor pressure

Answer 45

: pressure developed by the osmotic swelling tendency of cells having a higher concentration of osmotically active molecules internally than is in the external medium

Question 46

vacuole

Answer 46

: membrane-bounded organelle often used as a storage compartment in eucaryotic cells, particularly large in many plant cells

Question 47

vesicle

Answer 47

: a small membrane-bound structure filled with an aqueous solution.