Unit 5 Study Guide Flashcards
Differentiate between genotype and phenotype.
Genotype is an organism’s genetic make-up for a trait and the phenotype is the physical trait that can be seen.
What is the Law of Segregation?
Mendel’s Law of Segregation states that alleles on homologous chromosomes move independently of one another.
What is the Law of Independent Assortment?
Mendel’s Law of Independent Assortment says that each pair of homologous chromosomes moves to the metaphase plate during Metaphase 1 independently and the placement of the chromosome on the metaphase plate is random.
Explain Incomplete Dominance and give an example.
Incomplete dominance (has a heterozygous phenotype)is when information from both alleles is expressed in the cell and neither phenotype is completely penetrant. (Ex. Red + White = Pink)
Explain Codominance and give an example
Codominance is when both alleles are expressed in the cell and equally present in the phenotype. (Ex. black and white fur)
What is a pedigree? What do squares represent? Circles? Shaded shapes?
A pedigree is a family history of trait occurrence in chart form. It helps to tell past and future occurrences of a trait. Squares represent males and circles represent females. Fully shaded shapes mean that the person has the trait and half shaded shapes mean that person is a carrier.
What is a recessive disorder? Give an example and symptoms.
A recessive disorder can only occur in the homozygous recessive state. An example is cystic fibrosis which creates a faulty Chloride ion protein carrier on cell membranes in the lungs. This causes fluid to build up in the lungs.
What is a dominant disorder? Give an example and symptoms.
A dominant disorder only needs one allele for it to be expressed. One example of a dominant disorder is Achondroplasia. The people with this disorder are very short.
What is a gene? Locus? Genome?
A gene is a unit of hereditary information in the form of a DNA sequence of nucleotides. A locus is the location of a gene on a chromosome. A genome is an organism’s entire genetic make-up.
What is asexual reproduction? Give some benefits and risks.
Asexual reproduction is when the parent produces genetic clones of itself. The benefit is that it can happen very quickly. The risk is every organism is exactly the same.
What is sexual reproduction? Give some benefits and risks.
Sexual reproduction is when 2 parents contribute DNA. The benefit is it creates variation. The risk is it takes 2 to reproduce and it takes more time.
What is a karyotype?
A karyotype is a picture of the chromosomes
What are somatic cells? What are germ cells? How do they differ?
Somatic cells are body cells. Germ cells (gametes) are sex cells. Somatic cells have 46 chromosomes while germ cells only have 23.
What 3 things must occur for meiosis to happen correctly?
The 3 things that must occur for meiosis to happen correctly are 1 DNA replication and 2 cell divisions.
List 3 major differences between meiosis and mitosis.
The 3 major differences between meiosis and mitosis are the crossover in Prophase 1, chromosome pairs independently sort in Metaphase 1, and the sister chromatids separate in Anaphase 1.
