Bio: Unit 3

• What does meiosis enables?

  genetic variation
• What is crossing over?


  A piece of one chromosome is physically removed and put into another chromesome
• What is the purpose of crossing over?

  Create genetic diversity
• What happens if a person has an extra 21st chromosome?

  Down syndrome (Trisomy 21)
• What are genes recipes for?

  proteins
• How many genes does each chromosome have?

  roughly 500-5000
• Humans have ___ copies of each chromosome

  2
• Humans have 2 copies of each chromosome, therefore have __ copies of every gene

  2
• What are alleles?


  Alleles are alternative forms of a gene that occupy the same position on a chromosome and determine specific traits.
• Your 2 gene copies do not need to be...

  identical
• What is the definition of homozygous?

  2 exact copies of a gene
• What is the definition of heterozygous?

  2 different copies of a gene
• Who is considered the founder of genetics?

  Gregor Mendel
• Alleles are variants of...

  genes
• ___ alleles for every gene

  2
• What is Mendel's law of segregation?

  You inherit one set of alleles from one parent and the second set of alleles from the other parent (one from egg and one from sperm)
• What is Mendel's law of independent assortment?


  Children of the same biological parents are not identical, you are a unique mixture of your parent's genetics
• What are genotypes?


  Genetic background, collection of alleles
• What are phenotypes?

  Physical characteristics and can be impacted by the environment
• What are dominant phenotypes?

  Observable traits resulting from dominant alleles, only need one dominant allele needed to see dominant phenotype
• What does AA Homozygous mean?

  Dominant phenotype
• What does Aa Heterozygous mean?

  Dominant phenotype
• What does aa Homozygous mean?

  recessive genotype
• Healthy hemoglobin is ___ to having sickle cell diseases

  dominant
• What is heterozygotes' advantage?

  For some alleles + phenotypes, heterozygous genotypes can be advantages (ex: Sickle Cell Disease)
• Why are people with sickle cell disease immune to getting malaria?

  Heterozygous advantage (Hh)
• What are carriers in genetics?

  Individuals who carry a recessive genetic mutation but do not display the associated trait (heterozygote for a visible phenotype)
• What are punnet squares?

  a way to predict your kids genotype and phenotype
• What are gametes?

  Specialized reproductive cells that contain half the number of chromosomes as normal body cells.
• Gametes are ___ (1 copy of every gene or 1 allele for every gene)

  haploids
• What are zygotes?

  a cell formed by the union of two gametes (sperm + egg meeting)
• Zygotes are ___ (2 alleles for every gene)

  diploid
• What process creates a zygote?

  Fertilization
• What is Monohybrid Cross​ Demonstrates ​Law of Segregation

   Demonstrates how you inherit one allele of each gene from each parent

  
• A gene is a sequence of

  nucleotides
• What are alleles?

  Slightly different nucleotide sequences of the same gene
• What is a phenotype of humans who are carriers of Sickle Cell Disease?

  Round red blood cells
• Individuals heterozygous for Sickle Cell Disease are

  Carry one recessive allele for sickle cell disease and are protected from the disease malaria
• If a human has sickle cell amenia, their genotype for hemoglobin ...

  hh
• The Punnett Square shows all possible combinations of genes that can be inherited by offspring.