Write the letter of the matching definition next to each term.
1. isotope
A. Plastid containing ___ and other pigments
2. ionic
B. The dialect of Ancient Greek spoken and written in Attica and Athens and ___
3. covalent
C. A unicellular organism having cells lacking membrane-bound nuclei
4. lipid
D. An organism with cells characteristic of all life forms except primitive microorganisms such
5. nucleotide
E. Any of several complex proteins that are produced by cells and act as catalysts in specific
6. catalyst
F. The part of an enzyme or antibody where the chemical reaction occurs
7. exothermic
G. Any of various compounds composed of fatty acids and ___ acid and a nitrogenous base
8. endothermic
H. Center of an atom or a cell
9. enzyme
I. A phosphoric ester of a ___
10. substrate
J. Of or relating to or characterized by ___
11. activesite
K. Occurring or formed with absorption of heat
12. phospholipid
L. The ___ that is acted upon by an enzyme or ferment
13. eukaryote
M. An organelle in the cytoplasm of a living cell
14. prokaryote
N. A small round body of protein in a cell ___
15. nucleus
O. A pliable sheet of tissue that covers or lines or connects the organs or cells of animals or plants
16. nucleolus
P. Occurring or formed with the liberation of heat
17. lysosome
Q. The process in which there is movement of a substance from an area of high concentration of
18. reticulum
R. A substance that initiates or accelerates a chemical reaction without itself being affected
19. membrane
S. An organelle found in the cytoplasm of most cells
20. ribosome
T. Any fine network
21. chloroplast
U. Diffusion of molecules through a semipermeable membrane from a place of higher concentration to
22. diffusion
V. An oily organic compound insoluble in water but soluble in organic solvents
23. osmosis
W. One of two or more atoms with the same atomic number but with different numbers of neutrons