Variation and Evolution

• What does DNA stand for?

  Deoxyribonucleic acid
• What is the role of DNA in cells?

  It carries genetic information
• How is genetic material organized in cells?

  Into packages called chromosomes
• What determines inherited characteristics in an organism?

  The information in its genes
• Where is DNA found in animal and plant cells?

  In the nucleus
• What shape does DNA take?

  A double helix
• What is a gene?

  A small section of DNA
• What does each gene code for?

  A specific sequence of amino acids
• How many amino acids are used to make proteins?

  Twenty
• What determines the type of cell produced?

  The proteins the cell produces
• What is a genome?

  The entire set of genetic material
• Why is understanding the human genome important?

  It aids in science and medicine
• How can scientists use the human genome?

  To identify genes linked to diseases
• What can knowing the genes linked to inherited diseases help with?

  Understanding and developing treatments
• How can genomes help trace human migration?

  By investigating genetic differences
• What common ancestor do all modern humans descend from?

  A common ancestor in Africa
• What influences the development of different human populations?

  Migration and genetic differences
• What are the repeating units that make up DNA strands?

  Nucleotides
• What three components make up each nucleotide?

  Sugar, phosphate group, and base
• How do sugar and phosphate groups arrange in DNA strands?

  They alternate in the backbone
• Which bases can join to each sugar in DNA?

  A, T, C, or G
• What is complementary base pairing in DNA?

  A pairs with T, C pairs with G
• What determines the order of amino acids in a protein?

  The order of bases in a gene
• How many bases code for each amino acid?

  Three bases
• What happens to amino acids after they are coded?

  They are joined to make proteins
• What is the role of non-coding parts of DNA?

  They control gene expression
• Where are proteins made in the cell?

  In the cytoplasm on ribosomes
• Why can't DNA move out of the nucleus?

  Because it is too big
• What molecule carries the code from DNA to ribosomes?

  mRNA
• What is the function of mRNA in protein synthesis?

  It carries the code between DNA and ribosomes
• How are the correct amino acids brought to ribosomes?

  By carrier molecules in the correct order
• What happens to a chain of amino acids after assembly?

  • It folds into a unique shape
  • This shape allows the protein to perform its function
• What are the types of proteins and their functions?

  1. ENZYMES: Speed up chemical reactions
  2. HORMONES: Carry messages in the body
  3. STRUCTURAL PROTEINS: Provide strength (e.g., collagen)
• What are changes in DNA sequences called?

  Mutations
• What is a mutation?

  • A random change in DNA
  • Can be inherited
  • Occurs constantly
• What can increase the chance of mutations?

  Exposure to certain substances or radiation
• How do mutations affect the DNA sequence?

  They change the sequence of DNA bases
• What do mutations sometimes lead to?

  Changes in the protein coded by the gene
• What is the effect of most mutations on proteins?

  They have little or no effect
• How can some mutations affect protein function?

  By altering the protein's shape