Unit 4 Vocabulary
1. Eukaryoteorganism whose cells
contain a nucleus; Ex:
plants, animals
2. Prokaryoteorganism whose cells
do not contain a
nucleus; Ex: bacteria
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3. cell theory-
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4. Robert Hooke- first scientist to view cells
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5. organelle- specialized
structure that performs
important cellular functions
within a eukaryotic cell
#6
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6. cell wall- provides structure for plant cells; barrier, helps control water
content
#7
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7. Cell/plasma membrane- forms boundary; semipermeable, acts as
‘gatekeeper’ by controlling what enters & exits the cell
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8. nucleus- holds & protects the DNA; ‘control center’ of cell
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9. nucleolus- mix of proteins & nucleic acids; produces ribosomes
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10. chromosomes/chromatin/DNA- the genetic material found in the nucleus
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11. nuclear membrane- surrounds the nucleus to protect DNA
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12. cytosol- fluid in cell, mostly water; where many cellular reactions take place
cytoplasm- cytosol & organelles
Cytoplasm/Cytosol
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13. centriole- help to organize
cell division; in animal cells only
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14. endoplasmic reticulum (ER)- assembles
lipids, proteins; ‘factory’ of cell
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15. ribosomes- synthesize proteins
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16. chloroplast- conducts photosynthesis (produces sugar); ‘solar power
plant’ of cell
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17. mitochondria- where cellular respiration takes place & energy is
released; ‘powerhouse’ of cell
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18. lysosomes- vesicles filled with enzymes; break down and recycles
molecules, old organelles; ‘recycling center’ of cell
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19. Golgi apparatus/body/complex- sac-like structures that sorts & packages
materials; ‘packaging center’ of cell
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20. vacuole- stores materials, especially water
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21. microtubules- hollow tubes that aid in cell division and help cells maintain
their shape; form cytoskeleton, the framework of the cell
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22. vesicle- membrane-enclosed structures used for transport
Moving substances
into cell:
Moving substances
out of cell:
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23. cell differentiation- process in which cells become
specialized in structure and function
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24. cancer- disorder in which some of the body’s cells lose the ability to control
growth
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25. nucleated- contains a nucleus
Eukaryotic cells are nucleated because they contain nuclei.
26. synthesize- to make something or combine things together
Ribosomes synthesize proteins.
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27. unicellular- an organism composed
of a single cell; ex: prokaryotes like
bacteria
28. multicellular- an organism
composed of many cells; ex: humans,
trees
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29. respiration- exchanging carbon dioxide and oxygen; breathing
Your cells respire so that they have the oxygen necessary for breaking down
glucose (cellular respiration)
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30. plasmolysis- the shrinking of the cytoplasm of a plant cell due to water
loss, causing gaps between the cell wall and cell membrane
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31. osmosis- the diffusion of water across a membrane
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32. diffusion- process where
particles move from an area of high
concentration to an area of low
concentration
33. diffusion gradient- a difference
in the concentration of particles
from high to low
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34. passive transport- the
movement of materials
across the cell membrane
without using cellular
energy; ex: diffusion
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35. active transport- the movement of materials
against a concentration difference; requires
energy; ex: pumping calcium across a membrane
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36. permeable- allows substances to pass through
37. impermeable- does not allow substances to pass through
38. differentially permeable/semipermeable- allows some things to pass
through but not others, as with the cell membrane
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39. isotonic- when solute concentrations
are equal inside and outside of the cell
and water moves in and out at the same
rate; means ‘same strength’
Animal Cell:
Plant Cell:
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40. hypertonic- when the concentration
of solutes is high outside of the cell,
causing water to leave; means ‘above
strength’
Animal Cell:
Plant Cell:
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41. hypotonic- when the concentration
of solutes is lower outside of the cell,
causing water to enter; means ‘below
strength’
Animal Cell:
Plant Cell:
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42. secretion- the production and release of a useful substance; ex: a cell
excreting a hormone
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The volume of a cell increases much faster than its
surface area! This causes transport of molecules in and
out of the cell to be too slow for the cell to survive!
43. surface area- the total area of the outside of an object
44. volume- the total amount of space inside an object
45. surface area : volume ratio- the amount of surface area per unit volume;
helps explain why cells must be small
Relative Surface Area:
Relative Volume:
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46. mitosis- type of cell division resulting in 2 identical cells
47. spindle- a fan-like system of microtubules that will help to separate
duplicated chromosomes
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48. chromatid- each DNA strand in a
duplicated chromosome
49. centromere- where replicated
DNA/chromosomes attach to each other
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50. replication- the act of copying or
reproducing something
DNA is replicated during interphase.
51. interphase- the period of the cell
cycle between cell divisions; includes
cell growth and DNA replication
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52. prophase- 1st phase of mitosis;
DNA condenses into chromosomes
and spindle fibers form
53. metaphase- 2nd phase of mitosis;
chromosomes line up in center of cell,
pulled by spindle fibers
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54. anaphase- 3rd phase of mitosis;
the chromosomes separate and move
to opposite sides of the cell
55. telophase- 4th phase of mitosis;
the chromosomes unwind and nuclear
membranes reform
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56. cytokinesis- division of the cytoplasm, splitting the cell in two
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57. Why are cells so small?
The volume of a cell increases much faster than its surface area. This causes
passive transport of molecules in and out of the cell to be too slow for the cell to
survive because the distance the molecules must travel has become very large.
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58. What is the end product of
mitosis?
The end product of mitosis is two
identical cells.
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59. When would a cell undergo mitosis?
A cell undergoes mitosis when its surface area to volume has become to great
for the cell to rely on passive transport to survive. Mitosis begins after
interphase, when the cell grows in size and replicates its DNA.