Download holt mcdougal Genetics VOCAB

1. Carrier - does not show disease symptoms but can pass on the disease-causing allele to
offspring.
2. Sex-linked genes - Genes that are located on the sex chromosomes
3. X chromosome inactivation - In each cell of female mammals, one of the two X chromosomes is
randomly “turned off”
4. Incomplete dominance - in which a heterozygous phenotype is somewhere between the two
homozygous phenotypes
5. Codominance - in which both traits are fully and separately expressed
6. Polygenic traits - Traits produced by two or more genes
7. Linkage maps - which are maps of the relative locations, or loci, of genes on a chromosome
8. Pedigree - can help trace the phenotypes and genotypes in a family to determine whether
people carry recessive alleles
9. Karyotype - is a picture of all the chromosomes in a cell
10. Bacteriophage - takes over a bacterium’s genetic machinery and directs it to make more viruses
11. Nucleotides - The small units, or monomers, that make up DNA
12. Double helix - in which two strands of DNA wind around each other like a twisted ladder
13. Base pairing rules - thymine (T) always pairs with adenine (A), and cytosine (C) always pairs with
guanine (G).
14. Replication - process by which DNA is copied during the cell cycle
15. DNA polymerases - bond the new nucleotides together
16. Central dogma - which states that information flows in one direction, from DNA to RNA to
proteins
17. RNA - or ribonucleic acid, is a chain of nucleotides, each made of a sugar, a phosphate group,
and a nitrogen containing base
18. Transcription - the process of copying a sequence of DNA to produce a complementary strand of
RNA
19. RNA polymerases - enzymes that bond nucleotides together in a chain to make a new RNA
molecule
20. Messenger RNA - an intermediate message that is translated to form a protein
21. Ribosomal RNA - forms part of ribosomes, a cell’s protein factories
22. Transfer RNA - brings amino acids from the cytoplasm to a ribosome to help make the growing
protein
23. Translation - is the process that converts, or translates, an mRNA message into a polypeptide
24. Codon - is a three-nucleotide sequence that codes for an amino acid
25. Stop codons - signal the end of the amino acid chain
26. Start codon - which signals the start of translation and the amino acid methionine
27. Anticodon - is a set of three nucleotides that is complementary to an mRNA codon
28. Promoter - is a DNA segment that allows a gene to be transcribed
29. Operon - is a region of DNA that includes a promoter, an operator, and one or more structural
genes that code for all the proteins needed to do a specific task
30. Exons - are nucleotide segments that code for parts of the protein
31. Introns - are nucleotide segments that intervene, or occur, between exons
32. Mutation - a change in an organism’s DNA
33. Point mutation - a mutation in which one nucleotide is substituted for another
34. Frameshift mutation - involves the insertion or deletion of a nucleotide in the DNA sequence
35. Mutagens - agents in the environment that can change DNA