genetics yr1

• what are the 3 components of a nucleotide?


  pentose Sugar, phosphate, nitrogenous base
• difference in rna and dna sugar?

  RNA: Ribose DNA: Deoxyribose
• role of RNA?


  transfer information to ribosomes for protein synthesis
• how is DNA different in prokaryotic and eukaryotic cells?


  p= no proteins , short , circular

  e= long , in nucleus , histones
• features of the genetic code?


  Universal, degenerate, non-overlapping
• whats a locus?


  a fixed position of a gene on a DNA molecule
• describe structure of tRNA?


  Cloverleaf-shaped , anticodon and ammino acid binding site
• whats splicing?


  Splicing is the process of removing introns from pre-mRNA and joining exons together to form mature mRNA.
• why might a mutation not lead to a difference in ammino acid sequence?


  may occur in intron or code is degenerate
• what is a substitution mutation?


  A substitution mutation is a type of genetic mutation where one nucleotide is replaced by another in the DNA sequence.
• what is a deletion mutation?


  A deletion mutation is a type of genetic mutation where a segment of DNA is lost or deleted , leads to frame shift
• what are mutagenic agents ?


  Agents that cause mutations.
• what is chromosome non-disjunction?


  Failure of chromosomes to separate properly during cell division.
• what is meiosis?


  Cell division process that produces gametes with half the number of chromosomes as the parent cell , haploid
• how are mitosis and meiosis different?


  Mitosis: cell division resulting in two identical daughter cells. Meiosis: cell division resulting in four genetically diverse daughter cells.
• in what ways does meiosis produce genetic variation?


  Crossing over, independent assortment, and random fertilization.