types of reproduction-B13

• how does sexual reproduction cause variation ?

  • crossing over during first cell divison
  • independent segregation (how genes line up) in second cell division
  • random fertilization after gametes have been produced
• what is a homologous pair?

  A pair of chromosomes with the same genes, but different alleles
• what is a genotype?

  the combination of alleles for a characteristic
• what is a phenotype?

  expression of the genotype
• what is an allele?

  version of a gene
• describe the process of protein synthesis ?

  • DNA strands separate
  • MRNA transcribed
  • leaves nucleus for ribosome
  • bases read in groups of three
  • transport molecule with three complementary bases attaches to MRNA
  • transport molecule carry specific amino acid amino
  • acids join up in a chain
  • amino acids fold up dependant on sequence
  • shape folded protein determines function
• happens if there is a Gene mutation?

  • Change of sequence of bases
  • changing sequence of amino acids
  • changing bonds between amino acids
  • changing 3-D shape of protein changing function
• which bases join up together ?

  A-T

  C-G
• what is a base phosphate and sugar molecule join together called?

  Nucleotide
• asexual reproduction

  • mitosis
  • no gametes
  • produces clones.
  • One cell division
  • can happen using any body cell as parent cell.
• sexual reproduction:

  • meiosis
  • involves gametes
  • genetically different offspring
  • two cell divisions
  • germline sellers parents cell
  • produces haploid gametes
  • gametes fuse during fertilisation