| Mitosis and Meiosis | ||
| #1 | List the stages of mitosis in order. | Prophase, Metaphase, Anaphase, Telophase |
| #2 | What is a karyotype? | A karyotype is a photograph of chromosomes. |
| #3 | What does the diploid number mean and which cells are diploid? |
The diploid number is the number of chromosomes in a cell with two sets of chromosomes; has two sets of each gene; present in body cells (somatic cells) |
| #4 | What does the haploid number mean and which cells are haploid? |
The haploid number is the number of chromosomes in a cell with a single set of chromosomes; present in gametes (sex cells) only; half of the diploid number. |
| #5 | How does meiosis contribute to genetic variability? | Meiosis increases genetic variability by separating homologous chromosomes into individual gametes during Meiosis I and through the process of crossing over during Prophase I |
| Genetics | ||
| #1 | What is the principle of dominance? | Alleles can be recessive or dominant. Dominant alleles are always expressed. |
| #2 | What is an allele? | Alleles are the different forms of a trait (e.g., blue, brown, or green eyes) |
| #3 | What is the principle of segregation? | Alleles separate into different gametes during meiosis |
| #4 | Why does a recessive trait disappear and then reappear in future generations? | Recessive traits can be carried but not shown. Future generations may have homozygous recessive combinations resulting in the reappearance of a "lost" phenotype. |
| #5 | What is the difference between phenotype and genotype? | Phenotypes are traits that can be physically observed. Genotypes are the "genes" that determine your physical appearance; invisible to the observer. |
| Punnett Square | ||
| #1 | What is the purpose of a Punnett Square? | Geneticists create Punnett Squares to predict the future genotypes and phenotypes of individuals. |
| #2 | What do the terms heterozygous and homozygous mean? |
Heterozygous means the individual is a hybrid, or that they are carrying a dominant and recessive allele.
A heterozygote may also be called a "carrier" since they carry an allele that is not shown.
Homozygous means that they have two of the same allele, both dominant or both recessive. |
| #3 | Cross a heterozygous blue eyed female with a homozygous brown-eyed male. Brown is dominant to blue. List the possible genotypes and their percentages. List the possible phenotypes and their percentages. |
Genotypes: Bb, BB Phenotypes: 0% blue; 100% brown |
| #4 | Sickle Cell Anemia is a recessive disorder symbolized by "a". What is the likelihood a child will have the disorder if both parents are heterozygous for the disorder? List all possible genotypes. | 25% of children with the disorder. AA, aa, Aa |
| #5 | Huntington's Disease is caused by a dominant allele (H). What is the likelihood of the children having this disorder if both parents are heterozygous? List the genotypes. |
75%. Hh, HH, hh |
| Sex-linked Traits | ||
| #1 | What is a sex linked trait? | A sex linked trait is carried on the sex chromosomes ONLY. Usually on the X chromosome. |
| #2 | What symbols should be used for the games in a Punnett Square for sex-linked traits? | XX, XY; Each X should have an "exponent" to show the allele that is being carried. |
| #3 | Why does the "Y" allele for males not need an "exponent"? |
Y chromosomes do not usually carry sex linked genes. |
| #4 | If a male child has the allele for baldness, a sex-linked trait, which parent did he inherit the allele for baldness from? |
His mother, (X chromosome with the recessive allele) |
| #5 | If a bald man has a child with a woman that does not carry the baldness allele, what are the chances that their child will be bald? List all possible genotypes. |
0% for all children; 100% of females will be carriers; and none of the males will carry the trait or show the trait. XBXb, XBY |
| Pedigree Analysis | ||
| #1 | What do the different shapes in a pedigree analysis represent? |
Squares are males and circles are females |
| #2 | What does a shaded shape in a pedigree analysis represent? | Shaded shapes represent an individual that is affected by the gene of interest. The affected allele may be dominant or recessive. |
| #3 | If a daughter has a different phenotype than her parents, what is her genotype? | She must be homozygous recessive |
| #4 | Why are females more likely to be carriers of a recessive sex linked trait? | Because the X chormosome carreiers many traits that can be passed down to female offspring, but they will not show the trait unless the father also contributes a recessive trait on the x chromosome. If a male carriers a recessive sex linked trait, he will be showing it. |
| #5 | When looking at a pedigree analysis, how do you determine if someone is a carrier? |
A carrier is someone who has one recessive allele. You would need to look at their parents and/or their offspring. If any of their offpsring show a recessive trait then you know each of the parents must carry the allele even if they don't show it.
A carrier is also heterozygous for that trait. |
| Final Question | |
| Compare how humans and bacteria reproduce. Which one would likely have greater genetic variation and explain your reasoning? | Humans would likely have greater genetic variation as they reproduce sexually which provides a greater chance of various combinations of genes. Bacteria reproduce through asexual reproduction (Binary fission). |