Chapter 2 Vocabulary List
1. Biology – the study of life
2. Organism – a living thing
3. DNA – Deoxyribonucleic Acid; carries the genetic code
4. Nucleotide – monomer of DNA or RNA composed of phosphoric acid, sugar (deoxyribose for DNA and ribose
for RNA) and a nitrogen base (A,T,C,G for DNA and A,U,C,G for RNA).
5. Nitrogenous Bases – the parts of DNA and RNA that pair (A,T,C,G for DNA and A,U,C,G for RNA).
6. DNA Replication – the process of making another copy of the genetic code by a semi-conservative process.
Occurs within the nucleus
7. DNA Polymerase – enzyme that links DNA nucleotides together during DNA replication using a DNA strand as
a template. This enzyme also proofreads the new DNA strand and corrects any base pairing errors.
8. DNA Helicase –
9. Telomere – repetitive DNA at the end of a eukaryotic chromosome. This DNA is commonly lost during DNA
replication but is replaced by the enzyme DNA Telomerase.
10. RNA – Ribonucleic Acid
11. mRNA – messenger RNA (Messenger Ribonucleic Acid); single stranded molecule that carries the genetic
message from DNA within the nucleus to ribosomesoutside the nucleus
12. tRNA – transfer RNA (transfer Ribonucleic Acid); molecule the carries amino acids to ribosomes
13. rRNA – ribosomal RNA (Ribosomal Ribonucleic Acid); RNA that makes up ribosomes
14. Transcription – making mRNA from DNA; occurs within the nucleus
15. RNA Polymerase – enzyme that links RNA nucleotides together during transcription using a DNA strand as a
template.
16. Promoter – specific region of a gene where RNA polymerase can bind and begin transcription
17. Translation/Protein Synthesis – reading the mRNA codons to make proteins; occurs on the ribosomes
18. Amino Acids – the monomers of proteins
19. Proteins – molecules that make up parts of cells and sometimes act as enzymes
20. Ribosomes – small organelles within cells where translation/protein synthesis takes place
21. Intron – a sequence of DNA that is not involved in coding for a protein (90% of DNA is composed of introns).
22. Exon – a sequence of DNA that is “expressed” and therefore codes for a protein (only 10% of DNA consists of
exons).
23. Codon – a group of three nucleotide bases in mRNA that code for a specific amino acid
24. Anitcodon – a group of three nucleotide bases on a tRNA molecule complimentary to the three nucleotide bases
on a mRNA codon. Each anticodon carries a specific amino acid.
25. Polyploidy – condition in which an organism has an extra set of chromosomes.