cell division

• define gene?


  a short section of DNA that contains a sequence of bases
• where are genes found?

  in the chromosomes in nucleus of eukaryotic cells
• how is DNA found in a non-dividing cell?

  DNA is loosely structured around histone protiens as Chromatin fibres in the nucleus
• how is DNA found in dividing cels?

  the DNA replicates, condenses and supercoils around histone protiens in visible chromosomes
• what does a duplicates chromosome consist of (2 things)?

  centromere and chromatids

  (sister chromatids - genetically identical)
• define gene locus?

  location of a gene
• what occurs in interphase?

  • preparation for division
  • visible nucleus but no visible chromosomes
• define binary fission?


  a type of asexual reproduction in which a prokaryotic cell divides into 2 daughter cells, NO MITOSIS
• what are the 4 stages to binary fission?

  1. circular dna is replicated once. plasmids replicated many times-cell gets bigger (elongates)
  2. cytoplasm and cell membrane divides, new cell wall forms around new cells
  3. 2 daughter cells made, each contain one copy of circular dna and a variable number of plasmids
  4. daughter cells separate
• what features are ALWAYS present in a virus?

  • capsid
  • nucleic acid
  • attachment proteins
• State 4 key words for virus replication?

  1. Attachment
  2. injection
  3. replication
  4. release
• Describe the 4 stages to virus replication?

  1. Attachment - viral attachment proteins binds to specific and complimentary host cell receptor.
  2. injection- the virus' genetic material enters the host cell
  3. replication- viral and host cell enzymes to produce more viral protien acids, viral particles assemble.
  4. release- new virus exits the host cell (budding/lysis)
• Virus Replication:

  A) attachment

  B) host

  C) dna

  D) replication

  E) replicates

  F) protiens

  
• Binary Fission:

  A) replicates

  B) elongates

  C) replicated

  D) divides

  E) two daughter cells

  
• Virus Structure:

  A) attachment protein

  B) nucleic acid

  C) reverse transcriptase

  D) capsid

  E) envelope

  F) integrase