Genetics unit exam

• What are sister chromosomes?

  Two halves of a replicated chromosome. Contains identical DNA
• What is a centromere

  Attaches two sister chromatids to form a replicated chromosome. Center of chromosome
• Purpose of Prophase of Mitosis

  Purpose: For growth and the replacement of worn out cells. The creation of new cells
• Purpose of Meiosis

  Purpose: To create haploid cells and to separate homologous pairs.

  Gametes in animals

  Spores in plants
• End result of Mitosis is two identical daughter cells with the same number of chromosomes as the parent cell
• End result of Meiosis is 4 gamete cells
• Cells are different after meiosis, due to homologous crossover which occurs in Prophase 1
• Homologous pairs separate in Anaphase 1
• Is there an inter phase between Meiosis 1 and 2?

  no
• Humans have 46 chromosomes, 23 pairs
• Diploid is 2N
• Haploid is N
• Homologous chromosomes are identical chromosomes that carry the same genes. One from mother and other from father
• In meiosis 1, two haploid cells are produced
• in meiosis 2, 4 haploid cells (gametes) are produced from the 2 haploid cells produced from meiosis 1
• Homologous chromosomes pair up in Meiosis Metaphase 1
• Crossing over occurs in Meiosis prophase 1. Purpose is to create genetic variation
• Homologous chromosomes separate in Meiosis anaphase 1
• nondisjunction is when one or more homologous chromosomes fail to separate during cell division resulting in abnormalities. Occurs in Meiosis anaphase
• karyotype is an individual's complete set of chromosomes. They tell us the size and shape of each chromosome.
• Law of segregation

  When in meiosis, one diploid gamete will be split into 4 haploid gametes. Each of these gametes will receive one of the two alleles for every gene. This allows for all the offspring to have different traits step 3 of meiosis (Metaphase 1)
• Law of independent assortment is when the alleles for any two genes separate independently
• gene

  coded instructions for DNA that is passed down to offspring
• Allele?

  a version of a gene that are found on the same locations on chromosomes
• Autosomal occurs when the inheritance of a disease is found in common occurrences between genders. It is autosomal when the mutation is found on one of the 22 autosomal chromosomes. (There is on pair of sex chromosomes)
• Sex-linked occurs when the mutation occurs on one of the X or Y chromosomes. This usually means that males are more frequently affected  than females
• Dominant is when the mutated trait is dominant to the recessive. Dominant traits ACTUALLY DO SMT
• Recessive traits are recessive to the dominant traits. They DO NOT DO ANYTHING.
• Polygenic inheritance is when there are two or more genes being crossed for a trait
• Chromosome theory of inheritance explains how genes are found in specific locations on the chromosomes. These chromosomes are transmitted from parent to offspring 
• Law of Independent Assortment states that alleles at different locations can be inherited independently of each other
• Law of Segregation states that alleles separate during gamete formation so that only one copy of an allele goes into each gamete
• Mendelian genetics is based on Mendels work with pea plants, where he discovered the laws of segregation and independent assortment