Theory of Biological Damage from Radiation Exposure

Question 1

Single Strand Break

Answer 1

Only 1 of the DNA helices breaks

Readily repaired though improper repair is possible

Question 2

Double Strand Break

Answer 2

Both helices suffer a break either directly opposite one another or separated by only a few base pairs
Difficult or impossible to repair
Lead to apoptosis, mutation, or carcinogenesis

Question 3

3 major lethal abberations

Answer 3

Dicentric
Ring
Anaphase

Question 4

2 major non-lethal abberations

Answer 4

Translocation

Deletion

Question 5

Dicentric Abberation

Answer 5

Illegitimate union after a DSB, DNA replicates creating dicentric chromosome plus acentric fragment

Unstable, usually lead to cell death and are not passed on to progeny cells

Question 6

Ring Abberation

Answer 6

DSB in both arms of the same chromosome, broken ends connect creating an incorrect union, cell replicates creating overlapping rings

Question 7

Bridge Abberation

Answer 7

DSB occursin in each chromatid of a post-replication chromosome
Broken ends connect creating sister union
Forms dicentric chromatid and acentric chromatid fragment

Question 8

Symmetric Translocation

Answer 8

DSB in adjacent, pre-replication chromosomes
Broken pieces exchanged
May lead to cell death or cancer if suppressor gene is lost in fragment
Stable abberation that can persist for many years and are passed on to progeny cells

Question 9

Small Interstitial Deletion

Answer 9

Adjacent breaks in pre-replication chromosome
Broken ends connect creating an acentric ring fragment
Fragment is lost at next mitosis
May lead to cell death or cancer if suppressor gene is lost in fragment