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IGHS Winkels
Biology Chapter 12
| Term | Definition |
|---|---|
| transformation | heat-killed bacteria passed their disease-causing ability to a harmless strain of bacteria |
| bacteriophage | a virus that infects bacteria |
| nucleotide | units that make up DNA |
| base pairing | hydrogen bonds in DNA can form only between adenine and thymine and between guanine and cytosine |
| chromatin | unwound DNA found in the nucleus of a cell |
| histone | protein molecule around which DNA is tightly coiled in chromatin |
| replication | copying process by which a cell duplicates its DNA |
| DNA polymerase | enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule |
| genes | are coded DNA instructions that control the production of proteins within the cell |
| messenger RNA | RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell |
| ribosomal RNA | type of RNA that makes up the major part of ribosomes |
| transfer RNA | type of RNA molecule that transfers amino acids to ribosomes during protein synthesis |
| transcription | process in which part of the nuleotide sequence of DNA is copied into complementary sequence in RNA |
| RNA polymerase | enzyme similar to DNA polymerase that binds to DNA and separates the DNA and separates the DNA strands during transcription |
| promoter | region of DNA that indicates to an enzyme where to bind to make RNA |
| intron | sequence pf DNA that is not involved in coding for a protein |
| exon | expressed sequence of DNA; codes for a protein |
| codon | 3-nucleotide sequence on messenger RNA that codes for a single amino acid |
| translation | decoding of a mRNA message into a polypeptide chain |
| anticodon | group of 3 bases on a tRNA molecule that are complementary to an mRNA codon |
| mutation | change in a DNA sequence that affects genetic information |
| point mutation | gene mutation involving changes in one or a few nucleotides |
| frameshift mutation | mutation that "shifts" the "reading" frame of the genetic message by inserting or deleting a nucleotide |
| polyploidy | the condition in which an organism has extra sets of chromosomes |
| operon | a group of genes that operate together |
| operator | region of chromosome in an operon to which the repressor binds when the operon is "turned off" |
| differentiation | process in which cells become specialized in structure and function |
| hox genes | series of genes that controls the differentiation of cells and tissues in an embryo |