DNA

• What does DNA stand for?

  Deoxyribonucleic acid
• What is DNA made of?

  It is a polymer of similar units
• How many strands does DNA have?

  Two strands
• What shape does DNA form?

  A double helix
• How is DNA organized in a cell?

  Separated into 46 different sections
• What do we call the tightly coiled sections of DNA?

  Chromosomes
• How many chromosomes does each human cell have?

  46 chromosomes
• How many different types of chromosomes are there?

  23 different types
• What is unique about the 23rd pair of chromosomes?

  They are the sex chromosomes
• What chromosomes do women have?

  Two X chromosomes
• What chromosomes do men have?

  One X and one Y chromosome
• When do chromosomes appear in an X shape?

  Just before cell division
• What is a gene?

  A small section of DNA coding for protein
• What does a gene code for?

  A particular sequence of amino acids
• How many different types of amino acids are there?

  20 different types
• How does DNA influence cell type?

  It determines which proteins are produced
• What protein do red blood cells need to transport oxygen?

  Hemoglobin
• What is a genome?

  The entire set of genetic material
• What can scientists do with the complete human genome?

  Identify genes linked to diseases
• What is an inherited disease?

  A disease caused by inherited genes
• How can genes affect disease risk?

  They may increase the risk of diseases
• What can doctors do by examining genes?

  Choose more effective treatments
• How can genomes help trace human migrations?

  By showing genetic differences between populations
• What can small differences in genomes indicate?

  When populations separated
• What is the relationship between DNA, chromosomes, genes, and genomes?

  • DNA is the genetic material.
  • Chromosomes are tightly coiled DNA sections.
  • Genes are segments of DNA coding for proteins.
  • The genome is the complete set of genetic material.
• What are the differences between inherited diseases and risk-increasing genes?

  • Inherited diseases: caused by specific genes inherited from parents.
  • Risk-increasing genes: may increase the likelihood of developing a disease but do not directly cause it.
• What is an allele?

  A variant form of a gene
• What is the difference between dominant and recessive alleles?

  Dominant alleles are expressed over recessive ones
• What does homozygous mean?

  Having two identical alleles for a gene
• What does heterozygous mean?

  Having two different alleles for a gene
• What is a gene?

  A segment of DNA coding for a protein
• How do genes determine characteristics?

  They code for proteins that influence traits
• What is an example of a trait determined by a single gene?

  Fur color in mice
• How are most characteristics determined?

  By several interacting genes
• What is the significance of alleles?

  They are different versions of the same gene
• How many alleles do we have for each gene?

  Two alleles, one from each parent
• What does it mean if an organism is homozygous recessive?

  Both alleles are for the recessive trait
• What color would a heterozygous mouse be if purple is dominant over green?

  The mouse would be purple
• What is the genotype?

  The entire collection of alleles an organism has
• What is the phenotype?

  The observable characteristics from the genotype