Quiz 14-17 PDF - Genetics

1. Homozygous trait: Both alleles are the same (AA or aa). 2. Heterozygous trait: Two different alleles (Aa). 3. Mendel’s Law of Segregation: Each individual has two alleles for a gene, which segregate during gamete formation, so each gamete carries only one allele. 4. Mendel’s Law of Independen...

1. Homozygous trait: Both alleles are the same (AA or aa). 2. Heterozygous trait: Two different alleles (Aa). 3. Mendel’s Law of Segregation: Each individual has two alleles for a gene, which segregate during gamete formation, so each gamete carries only one allele. 4. Mendel’s Law of Independent Assortment: Alleles for different traits assort independently of one another during gamete formation. 5. Complete dominance: One allele completely masks the effect of the other. Codominance: Both alleles contribute equally and visibly to the organism’s phenotype. Incomplete dominance: The heterozygote has an intermediate phenotype. 6. Examples: ○ Complete dominance: Brown eyes (B) vs. blue eyes (b). ○ Codominance: AB blood type. ○ Incomplete dominance: Red (RR) and white (WW) flowers produce pink (RW) flowers. 7. Allele: A variant form of a gene. 8. Dominant allele effect: A dominant allele masks the expression of a recessive allele in a heterozygote. 9. Polygenic inheritance: Traits controlled by multiple genes. Example: Skin color in humans. 10. Epistasis: One gene affects the expression of another gene. Example: Coat color in Labrador retrievers. 11. Gene: A sequence of DNA that codes for a protein or RNA molecule. 12. Locus: The specific location of a gene on a chromosome. 13. Linked genes: Genes located close together on the same chromosome and tend to be inherited together. 14. Nondisjunction: Failure of chromosomes to separate properly during cell division, leading to an abnormal chromosome number. 15. Aneuploidy: The presence of an abnormal number of chromosomes in a cell. 16. Sex-linked traits: Traits associated with genes located on the sex chromosomes. 17. SRY gene: The sex-determining gene found on the Y chromosome. 18. Watson and Crick: Developed the double helix model of DNA. 19. Nucleotide bases of DNA: Adenine (A), Thymine (T), Cytosine (C), Guanine (G). 20. Complementary and antiparallel: The strands of DNA have complementary bases and run in opposite directions (5' to 3' and 3' to 5'). 21. Model of DNA replication: Semiconservative replication. 22. Helicase: Unwinds the DNA double helix. 23. Topoisomerase: Relieves the tension caused by unwinding the DNA. 24. Single-strand binding proteins: Keep the single strands of DNA from re-annealing. 25. RNA primer enzyme: Primase. 26. RNA primer function: It provides a starting point for DNA polymerase to begin replication. 27. DNA polymerase: Adds nucleotides to the growing daughter strand. 28. DNA organization during replication: It forms a replication bubble with two replication forks. 29. End for nucleotide addition: DNA is built in the 3' → 5' direction. 30. DNA strand direction: DNA is synthesized in the 5' → 3' direction. 31. Lagging vs. leading strands: The leading strand is synthesized continuously; the lagging strand is synthesized in fragments (Okazaki fragments). 32. Okazaki fragments: Short DNA segments synthesized on the lagging strand. 33. Okazaki fragment connection enzyme: DNA ligase. 34. Replication fork: The Y-shaped region where the DNA is being unwound and replicated. 35. Origin of replication: The specific site where DNA replication begins. 36. Mutation: A change in the DNA sequence. 37. Protective structures during replication: Telomeres. 38. Pathway of genetic information: DNA → RNA → Protein. 39. Transcription: The process of making an RNA copy of a gene; occurs in the nucleus. 40. Translation: The process of synthesizing a protein from mRNA; occurs in the cytoplasm. 41. Transcription enzyme: RNA polymerase. 42. Difference between RNA and DNA: RNA uses uracil (U) instead of thymine (T). 43. Codon: A sequence of three nucleotides in mRNA that codes for a specific amino acid. 44. Anticodon: A sequence of three nucleotides in tRNA that is complementary to the codon in mRNA. 45. Exons vs. introns: Exons are coding regions; introns are non-coding regions. 46. Three types of RNA: mRNA (messenger RNA) carries genetic information. tRNA (transfer RNA) brings amino acids to the ribosome. rRNA (ribosomal RNA) makes up the ribosome. 47. RNA with anticodon: tRNA. 48. RNA that makes up ribosome: rRNA. 49. Three ribosome binding sites: A site (aminoacyl), P site (peptidyl), E site (exit). 50. Types of mutations during DNA replication: Point mutations, insertions, deletions. 51. Point mutation vs. frameshift mutation: Point mutation changes one nucleotide; frameshift mutation shifts the reading frame by adding or deleting nucleotides.