Describe the structure of a chromosome

Question 1

What is a chromsome?

Answer 1

• DNA molecule packaged into a thread-like sturcture

Question 2

Define chromatin, haploid and diploid (+ subcategories)

Answer 2

• Chromatin = Uncondensed
• Haploid - 23 chromosomes
• Diploid = 46 chromosomes
  
  • Autosomes and sex

Question 3

Give 3 (1,3, 5) featues and their purpose in the structure of a chromosome:

Answer 3

1. Histones
   * Coild around DNA = structural suppourt
2. Centromere

• Constriction = metacentric, submetacenrtic, acrocentric
• Divides into p & q arms
• Joins sister chromatids (mitosis)

3. Telomere

• ‘TTAGGG’ - Hexa-meric
• Stability
• Chromosome pairing
• DNA replication
• Cell longevity = shorter

Question 4

What is the need for geisma dye and the 2 consequnces as a result

Answer 4

• To stain condensed chromosomes to give light and dark bands through G banding (sticks to A-T rich regions)
  
  • DARK = Transcriptionally silent
  • LIGHT = Transcriptionally active