DNA

• What is a gene?

  A short section of DNA that contains a code for making a polypeptide and functional RNA
• What does a gene code for?

  A polypeptide and functional RNA
• What is a polypeptide chain?

  The primary structure of a protein
• What is the role of the Golgi apparatus in protein processing?

  It modifies polypeptide chains
• What is the definition of locus?

  The location of a gene on a chromosome
• Why are humans not genetically identical despite having the same genes?

  They have different versions of those genes (alleles)
• What is an allele?

  A different form of the same gene
• How do alleles affect traits in plants?

  They result in different versions of traits
• How many pairs of chromosomes do humans have?

  23 pairs
• What is a homologous pair?

  A pair of chromosomes with identical genes
• What determines biological sex in humans?

  The 23rd pair of chromosomes
• How is DNA stored in eukaryotic cells?

  In chromosomes within the nucleus
• What shape are eukaryotic chromosomes?

  Linear
• What prevents DNA from tangling in eukaryotic cells?

  Histone proteins help coil DNA
• What is a nucleosome?

  DNA wrapped around histone proteins
• How does prokaryotic DNA differ from eukaryotic DNA?

  It is shorter and circular
• Where is prokaryotic DNA located?

  Free in the cytoplasm
• What type of DNA do mitochondria and chloroplasts contain?

  DNA similar to prokaryotic DNA
• How do you calculate the mean length of DNA in each chromosome?

  Divide total length by number of chromosomes
• How do you calculate the number of base pairs per chromosome?

  Divide total base pairs by number of chromosomes
• What are the key differences between eukaryotic and prokaryotic DNA?

  • Eukaryotic DNA is linear; prokaryotic DNA is circular.
  • Eukaryotic DNA is associated with histone proteins; prokaryotic DNA is not.
  • Eukaryotic DNA is longer; prokaryotic DNA is shorter.
• What are the main points about chromosomes in eukaryotic cells?

  • Chromosomes are tightly coiled DNA.
  • Located in the nucleus.
  • Humans have 23 pairs (46 total).
  • Chromosomes can be single or double structures.
• What are the functions of histone proteins?

  • Assist in tightly coiling DNA.
  • Prevent DNA tangling.
  • Help form nucleosomes.
• What are the similarities between mitochondrial/chloroplast DNA and prokaryotic DNA?

  • Both are circular.
  • Both are shorter than typical eukaryotic DNA.
  • Both are not associated with histone proteins.
• What are the definitions of gene, allele, and locus?

  • Gene: A section of DNA coding for polypeptides.
  • Allele: A different form of the same gene.
  • Locus: The location of a gene on a chromosome.
• What is the significance of homologous pairs of chromosomes?

  • They have identical genes.
  • They may have different alleles.
  • They are formed during fertilization.
• What is the process of DNA compaction in eukaryotic cells?

  • DNA coils around histone proteins.
  • Forms nucleosomes.
  • Creates tightly packed chromosomes.
• What is the role of the Golgi apparatus in protein processing?

  • Processes polypeptide chains.
  • Modifies proteins for functionality.
  • Packages proteins for transport.
• What are the implications of having different alleles for a gene?

  • Different traits can be expressed.
  • Genetic diversity is increased.
  • Can lead to variations in phenotype.
• What is the importance of the 23rd pair of chromosomes in humans?

  • Determines biological sex.
  • Contains sex chromosomes (X and Y).
  • Influences reproductive traits.
• How is DNA organized in prokaryotic cells?

  • DNA is circular.
  • Not associated with histone proteins.
  • Located freely in the cytoplasm.
• What is the significance of a human karyotype?

  • Displays all chromosomes in pairs.
  • Helps identify chromosomal abnormalities.
  • Shows genetic similarities and differences.
• What is the relationship between DNA length and chromosome number in human cells?

  • Total DNA length is consistent across cell types.
  • DNA is distributed equally among chromosomes.
  • Each chromosome contains a fraction of total DNA.
• What is the process of converting DNA length from meters to millimeters?

  • Multiply the length in meters by 1,000.
  • Converts to millimeters for easier understanding.
  • Useful for calculations in biology.
• What is the significance of the base pairs in the human genome?

  • Approximately 3 billion base pairs exist.
  • Base pairs are distributed across 23 pairs of chromosomes.
  • Essential for genetic coding and function.