Biology I
Genetics Unit Terms
Chapter 9 (p. 178)
1. allele (p. 169): an alternative form of a gene
2. codominance (p. 176): an inheritance relationship in which neither of two alleles of the
same gene totally masks the other
3. complete dominance (p. 176): an inheritance relationship in which one allele is
completely dominant over the other; both Bb and BB have the same phenotype
4. dominant (p. 168): referring to an allele that masks the presence of another allele for the
same characteristic
5. F1 generation (p. 166): the offspring of cross-pollinated P1 generation of plants
6. F2 generation (p. 166): the offspring of self-pollinated F1 generation plants
7. genetics (p. 165): the field of biology devoted to understanding how traits are passed
from parents to offspring
8. genotype (p. 172): the genetic makeup of an organism
9. heredity (p. 165): the transmission of traits from parents to their offspring
10. heterozygous (p. 173): referring to a gene pair in which the two alleles do not code for
the same trait
11. homozygous (p. 173): referring to a gene pair in which the two alleles code for the same
trait
12. Law of independent assortment (p. 169): law stating that pairs of genes separate
independently of one another in meiosis
13. Law of segregation (p. 168): law stating that pairs of genes separate in meiosis and each
gamete receives one gene of a pair
14. P1 generation (p. 166): a strain obtained through self-pollination
15. phenotype (p. 172): the external appearance of an organism that is determined by the
individual’s genotype
16. phenotypic ratio (p. 175): the ratio of the offsprings’ phenotypes
17. probability (p. 173): the number of times an event is expected to happen divided by the
number of opportunities for an event to happen
18. Punnett square (p. 174): a model used to establish the probabilities of the results of a
genetic cross
19. pure (p. 166): Plants that are pure for a trait always produce offspring with that trait
20. recessive (p. 168): referring to an allele that is masked by the presence of another allele
for the same characteristic
21. strain (p. 166): denotes plants that are pure for a specific trait
22. testcross (p. 175): the crossing of an individual of unknown genotype with a
homozygous recessive individual to determine the unknown genotype
23. trait (p. 165): in genetics, a category within which alternate characteristics, such as
height and eye color, can be observed.
Chapter 10 page 197
1. codon (p 193): a group of three sequential nitrogen bases of an mRNA molecule
2. genetic code (p 193): triplets of nucleotides in mRNA that determine the sequence of
amino acids in protein
3. messenger RNA (p 191): called mRNA, the type of RNA that carries genetic
information from the nucleus to the ribosomes
4. mutation (p 189): a change in DNA
1
Biology I
Genetics Unit Terms
5. protein synthesis (p 193): the formation of proteins using information coded on DNA
and carried by RNA
6. replication (p 188): the process by which DNA copies itself during interphase
7. ribosomal RNA (p 191): called rRNA, the type of RNA found in a ribosome
8. transcription (p 191): the process in which RNA is made from DNA
9. transfer RNA (p 191): called tRNA, the type of RNA that carries amino acids from the
cytoplasm to the ribosomes
10. translation (p 194): the process of converting the genetic code in RNA into the amino
acid sequence that makes up a protein
Chapter 11 page 215
1. activation (p 205): the initiation of transcription by the removal of a repressor protein
2. benign tumor (p 211): an abnormal but non-threatening cell mass
3. cancer (p 211): the uncontrolled growth of cells
4. carcinogen (p 212): a cancer-causing substance
5. carcinoma (p 211): a malignant tumor that grows in body tissues
6. enhancer (p 208): a region adjacent to a eukaryotic gene that must be activated if the
gene is to be expressed
7. gene expression (p 203): the transcription of DNA into RNA and then into proteins
8. genome (p 203): the complete genetic material contained in an individual
9. growth factor (p 212): protein that regulates the rate and sequence of the events of cell
division
10. inducer (p 205): in the lac operon, the molecule that binds to repressor molecules and
induces gene expression
11. leukemia (p 211): a progressive, malignant disease of the blood-forming organs
12. lymphoma (p 211): a tumor in the tissues that form blood cells
13. malignant tumor (p 211): a cancerous mass of cells
14. metastasis (p 211): the spread of cancer cells beyond their original site
15. mutagen (p 212): an environmental factor that damages DNA
16. oncogene (p 214): a gene that induces cancer or other uncontrolled cell proliferation; a
mutated or activated proto-oncogene that is associated with the development of tumor
cells
17. operator (p 204): a sequence of DNA to which a repressor binds to prevent mRNA
synthesis from the adjacent gene; characteristically composed of one or more palindromic
sequences
18. pre-mRNA (p 207): a form of mRNA that contains introns and exons
19. regulator gene (p 205): a genetic unit that regulates or suppresses the activity of one or
more structural genes
20. repression (p 205): the blockage of transcription by the action of a repressor protein
21. repressor protein (p 205): a protein that inhibits a specific gene from being expressed
22. sarcoma (p 211): a tumor growing in bone or muscle tissue
23. structural gene (p 204): a gene that codes for a product, such as an enzyme, protein, or
RNA, rather than serving as a regulator
24. transcription factor (p 208): one of the additional proteins bound to enhancers and
RNA polymerase that regulate transcription
25. tumor (p 211): an abnormal mass of cells
2
Biology I
Genetics Unit Terms
26. tumor-suppressor gene (p 214): a gene that suppresses tumor formation but when
mutated causes a loss in cell function, resulting in tumor formation
Chapter 12 page 233
1. amniocentesis (p 232): a procedure used in fetal diagnosis in which fetal cells are
removed from the amniotic fluid
2. carrier (p 228): individuals who have one copy of a recessive autosomal allele
3. chromosome map (p 224): a diagram of allele positions on a chromosome
4. colorblindness (229): a recessive X-linked disorder in which an individual cannot
distinguish between certain colors
5. deletion (p 225): a mutation in which a segment of DNA breaks off of a chromosome
6. Down syndrome (p 231): a disorder caused by an extra twenty-first chromosome and
characterized by a number of physical and mental abnormalities
7. Duchenne muscular dystrophy (p 229): a form of muscular dystrophy that weakens and
progressively destroys muscle tissue
8. frame shift mutation (p 226): a mutation that results in the misreading of the code
during translation because of a change in the reading frame
9. germ-cell mutation (p 224): a change in the DNA of a sex cell
10. lethal mutation (p 224): a mutation that causes death, often before birth
11. linkage group (p 222): the group of genes, located on the same chromosome, that are
usually inherited together
12. multiple-allele traits (p 229): controlled by three or more alleles of the same gene that
code for a single trait
13. nondisjunction (p 225): the failure of homologous chromosomes to separate during
meiosis or the failure of sister chromatids to separate during mitosis
14. pattern of inheritance (p 228): certain phenotypes that are usually repeated in
predictable patterns from one generation to the next
15. pedigree (p 227): a diagram of the genetic history of an individual; can show how a trait
is inherited over several generations
16. phenylketonuria (PKU) (p 232): a genetic disorder in which the body cannot metabolize
phenylalanine
17. point mutation (p 225): the change of a single nitrogen-containing base within a codon
18. polygenic trait (p 229): a trait controlled by multiple genes
19. sex linkage (p 222): the presence of a gene on a sex chromosome
20. sex-influenced trait (p 229): a trait that is influenced by the presence of male or female
sex hormones
21. sickle cell anemia (p 226): a genetic disorder caused by a point mutation that substitutes
adenine for thymine in a single DNA codon. This substitution results in a defective form
of the protein hemoglobin.
22. single-allele trait (p 228): a trait controlled by a single allele
23. somatic mutation (p 224): a mutation that occurs in a body cell
24. translocation (p 225): a mutation in which a broken piece of chromosome attaches to a
nonhomologous chromosome; movement or organic molecules in plant tissues
25. trisomy (p 231): a chromosomal anomaly in which an individual has an extra
chromosome in any of the chromosome pairs
3
Biology I
Genetics Unit Terms
26. trisomy-21 (p 231): a human congenital disorder caused by trisomy of chromosome 21
due to the failure of the sister chromatids to separate during mitosis or the failure of
homologous chromosomes to separate during meiosis (see Down syndrome)
27. X-linked gene (p 222): a gene found on the X chromosome
28. Y-linked gene (p 222): a gene found on the Y chromsome
Chapter 13 page 253
1. cloning vector (p 240): a carrier used to clone a gene and transfer it from one organism
to another
2. DNA fingerprint (p 243): a pattern of bands made up of specific fragments from and
individual’s DNA
3. DNA technology (p 239): the technology involved in genetic engineering
4. gel electrophoresis (p 244): technique used to separate nucleic acids or proteins b size
and charge
5. gene clone (p 240): an exact copy of a gene
6. gene therapy (p 246): treatment of a genetic disorder by introducing a healthy gene into
a cell
7. genetic engineering (p 239): a form of applied genetics in which scientists directly
manipulate genes
8. herbicide (p 251): weed-controlling chemicals
9. Human Genome Project (p 246): worldwide scientific collaboration to determine the
nucleotide sequence of the entire human genome
10. insulin (p 241): a hormone that lowers the blood glucose level
11. pathogen (p 250): an organism that causes disease
12. recombinant DNA (p 241): a DNA segment from at least two different organisms
13. restriction enzyme (p 239): a protein that recognizes specific sequences in a DNA
molecule and cuts it into pieces
14. transgenic organism (p 242): a host organism that has received recombinant DNA
15. vaccine (p 250): a solution containing a harmless version of a virus, bacterium, or toxin
that causes an immune response when introduced to the body
4