Engineering Biology Problems Book (2021, Obninsk Edition)

Fig. 1.13. A) Tasmanian devil. B) Normal karyotype of a male: 14 chromosomes including XY. С)
Karyotype of tumor cells, observed in all 11 tumors: 13 chromosomes, 2nd chromosome and sex
chromosomes are absent, a single 6th chromosome, the 1st chromosome pair has restricted long arms,
four very disorganized chromosomes (M1-M4).
1.42 Microtubules in mitosis. Evaluate the amount of DNA that is transferred by one microtubule
during one cycle of mitosis. Evaluate the mean length of chromosomes in each organism in base pairs
(bp) and millimeters (1 bp = 0.34 nm) based on the data in table 1. Then evaluate the mean amount of
DNA in which is separated during mitosis. Is the last parameter the same in different organisms? ©
John Wilson, Tim Hunt. Molecular Biology of the Cell 6E - The Problems Book, 2015. (17-65)
Table 1. Amount of DNA, haploid number of chromosomes, and the number of microtubules for 1
chromosome in different organisms.
type species amount of
DNA (bp)
number of
chromosomes
number of microtubules for
1 chromosome
Yeast S. cerevisiae 1.4 × 107 16 1
Yeast S. pombe 1.4 × 107 3 3
Protist Chlamydomonas 1.1 × 108 19 1
Fly Drosophila 1.7 × 108 4 10
Human Homo sapiens 3.2 × 109 23 25
Plant Haemanthus 1.1 × 1011 18 120
SOLUTION:
The mean length of a chromosome and the mean number of bp transferred by one microtubule can be
seen in table 2. The value of length on DNA molecules varies from 0.9x10^6 bp in single-cell yeast
S.cerevisiae to 5.1x10^7 bp in the monocotyledon plant Haemanthus (difference of about 50 times).
Despite this parameter appears to be quite variable in different species, it is much more constant in
comparison to the mean length of chromosome DNA.
Table 2. Mean lengths of chromosomes and mean a number of bp for one microtubule in different
organisms.
type species mean
chromosome
length (bp)
mean length of
denatured
chromosome (mm)
Mean amount of
DNA for one
microtubule (bp)
Yeast S. cerevisiae 0.9x10^6 0.3 0.9x10^6
Yeast S. pombe 4.7x10^6 1.6 1.6x10^6
Protist Chlamydomonas 5.8x10^6 2.0 5.8x10^6