Mitosis

Question 1

What is DNA (deoxyribonucleic acid)?

Answer 1

• Double-stranded, helical chain found in the nucleus

- Carries genetic information that encodes proteins necessary for cells to reproduce and perform their functions

Question 2

What is a chromatin?

Answer 2

• Complex of DNA and histones (histones exist as octamers, 8 units, around which DNA winds
• Appear as a diffuse mass of thread-like structures in the nucleus of non-dividing cells

Question 3

What is a chromosome?

Answer 3

• Condensed chromatin that has been coiled/ folded many times upon itself
• Found in nucleus of dividing cells during mitosis and meiosis
• Tightly coiled and folded, thus appear fatter and shorter and visible

Question 4

What is a sister chromatid?

Answer 4

• Identical copies of DNA molecules as they are replicated from the same DNA molecules
• Attached at the centromere

Question 5

What is a centromere?

Answer 5

• Where sister chromatids are held together by cohesion proteins
• Required for correct alignment and segregation of chromosomes during nuclear division
• Where kinetochore will bind

Question 6

What are homologous chromosomes?

Answer 6

• A pair of chromosomes (in a diploid cell)

Question 7

What are the characteristics of homologous chromosomes?

Answer 7

• Similar in length, size, shape, centromere position and staining position
• Each homologue inherited from each parent
• Same genes at corresponding loci (eg blood group, hair colour)
• May no be identical in what they code for (different alleles at same locus)