Honors Biology: Genetics Unit Test

• point mutation (substitution)


  one nucleotide is replaced with a different nucleotide
• Genotypes and Phenotypes


  Genotype is genetic makeup (ex. PP, pp, Pp)

  Phenotype is physical traits (ex purple or white flowers)
• DNA


  A complex molecule containing the genetic information that makes up the chromosomes; contains deoxyribose sugar
• RNA


  single-stranded nucleic acid that contains the sugar ribose
• universal blood type

  Type O
• Universal blood donor

  Type O
• Universal blood recipient


  Type AB
• colorblindness and hemophilia


  examples of sex-linked traits; more common in males than females. BE ABLE TO EXPLAIN!
• Polygenetic


  two or more genes contribute to the phenotypic expression of a single characteristic
• Codominance example

  AB blood type
• incomplete dominance


  Situation in which one allele is not completely dominant over another allele
• homozygous dominant


  Both alleles (factors) for a trait are the same and dominant (AA)
• homozygous recessive

  aa
• sex-linked


  gene located on a sex chromosome
• XY


  male sex chromosomes
• XX


  female sex chromosomes
• Nature vs. Nurture


  name for a controversy in which it is debated whether genetics or environment is responsible for driving behavior
• Pleiotropy


  A single gene having multiple effects on an individuals phenotype
• polygenic inheritance

  An additive effect of two or more genes on a single phenotypic character.

  
• Karyotype analysis


  karyotype is print of human chromosomes the numbered chromosome pairs (autosomes) are arranged longest to shortest
• amniocentesis


  A technique of prenatal diagnosis in which amniotic fluid, obtained by aspiration from a needle inserted into the uterus, is analyzed to detect certain genetic and congenital defects in the fetus.
• multiple alleles


  three or more forms of a gene that code for a single trait
• testcross

  cross between an organism with an unknown genotype and an organism with a recessive phenotype
• law of independent assortment

  the law that states that genes separate independently of one another in meiosis

  
• Loci


  Location of a gene on a chromosome

  
• F2 generation

  offspring of the F1 generation
• F1 generation


  the first generation of offspring obtained from an experimental cross of two organisms
• Cross breeding programs


  Program which breeds two animals of different breeds, varieties or populations in an effort to increase hybrid vigor

  
• hybrid

  An organism that has two different alleles for a trait

  
• Codominance


  Two alleles are expressed in heterozygous individuals. EXAMPLE: BLOOD TYPE
• Incomplete Dominance


  A pattern of inheritance in which two alleles, inherited from the parents, are neither dominant nor recessive. The resulting offspring have a phenotype that is a blending of the parental traits.

  
• Law of Independent Assortment


  Alleles for different traits are distributed to sex cells (& offspring) independently of one another.
• Law of Segregation


  Mendelian law stating that two alleles for each trait separate during meiosis

  
• Law of Dominance


  In many traits one allele is dominant over the other allele. The "weaker (recessive" allele is only expressed when it is paired with another recessive allele).

  
• True or False: There is a 50% chance of having a boy and a 50% chance of having a girl.

  TRUE
• Who determines the sex of the child?

  dad
• Risk of passing on a disorder can be assessed by:

  genetic counselor, pedigree or prenatal counseling
• Blood type is determined by what?

  multiple alleles
• More sex-linked genes are found on the


  X chromosome due to size
• blood type

  A, B, AB, O