Knowledge Checks

• What is the haploid number of chromosomes in humans?

  23
• MITOSIS results in what kind of cells?

  diploid
• MEIOSIS involves DNA replication and how may divisions?

  2
• MEIOSIS results in what kind of cells?

  haploid
• MITOSIS involves DNA replication and how many divisions?

  1
• MEIOSIS results in what?

  Unique gametes
• What process that occurs between pairs of homologous chromosomes is illustrated here? Crossing over

  
• MEIOSIS occurs in what kind of cells?

  Sex cells
• Define Gene:


  A segment of the chromosome that produces a recognizable effect on phenotype and segregates as a unit during gamete formation.
• Define allele:

  One of two or more alternative forms of a gene. For example, the "A" and "S" alleles are two forms of the gene controlling the amino acid sequence of one of the sub-units of hemoglobin.
• Define genotype


  An individual's genetic makeup, what alleles an individual possesses.
• There are three kinds of genotypes. What are they and give an example using the dominant gene "T" and recessive gene "t"?

  Homozygous dominant (TT), heterozygous (Tt), homozygous recessive (tt).
• What is a phenotype?


  An individual's observable characteristics. The expression of the genotype influenced by the environment.
• What is homozygosity?

  Having two identical alleles for a particular gene.
• What is heterozygosity?

  The presence of different alleles at a particular gene locus.
• What is a dominant gene?

  A gene that is expressed in the phenotype when present.
• What is a recessive gene?

  A gene that is masked or overshadowed by a dominant gene.
• What is a Co-dominant gene?

  Both alleles are fully expressed in the phenotype.
• MITOSIS occurs in what kind of cells?

  Somatic cells
• MITOSIS results in what?

  exact copies
• Which force of evolution is likely working in the populations based on the graph below? Genetic Drift

  
• What occurs when individuals from neighboring populations interbreed?

  Gene flow.
• What kind of selection is indicated by the frequencies in the population in this graph: Balancing

  
• Does this graph indicate possible selection: yes

  
• What is a change in allele frequencies in a population due to differential reproductive success, which is environmentally dependent?

  Natural selection
• What is a result of a random change in DNA during replication? This is the ultimate source of new genetic variation.

  Mutation
• Which genotype is the most advantageous in a malaria environment?

  AS
• If everyone in a population has the best genotype for a malaria environment - why are the other genotypes still present? complete the punnett square to reveal the answer:

  On the upper left should be: A

  On the lower left should be: S

  Under "A" should be: AA

  Under "S" should be: SS

  
• A volcano explodes and kills all but ten members of a population of primates. These ten continue to reproduce, but the allele frequency is now different from that of the original population. This is an example of what which is due to sampling error?

  Genetic drift
• Which blood type has A and B antibodies?

  O
• Which blood type, besides AB, has B antigens on the surface of the red blood cells?

  B
• Which blood type, besides AB, has A antigens on the surface of the red blood cells?

  A