CH 8: DNA Replication (pt 2/2)

offspring of a cell

offspring of a cell

daughter cells

cell copies itself through..

DNA replication

origin of replication

site where initiator proteins attach to DNA. replication happens simultaneously at these sites.

topoisomerase

enzyme that untwists the double helix in DNA

helicase

enzyme that breaks hydrogen bonds between bases in DNA.

primers

short strands of DNA that bind to respective nucleotides

DNA ligase

seals any gaps in phosphate backbone strand

semiconservative replication

DNA doesn't make totally new strands when it replicates

3'

side of DNA strand that ends in 3 carbons

5'

side of DNA strand that ends in 5 carbons

DNA reads

5' to 3'

eukaryotic DNA polymerases

adds around 50 nucleotides per second

prokaryotic DNA polymerases

add around 1000 nucleotides per second

mutation

permanent change in the DNA sequence of a chromosome

mutagens

chemical that permanently changes DNA

retroviruses

use their own genetic material (RNA) to alter their host’s DNA

common causes for mutations during DNA replication

chemical exposure, infectious agents, oxidative stress, UV exposure, other forms of electromagnetic radiation

evolution is caused by..

constant mutations

if one parent has the gene for cystic fibrosis..

you're less likely to get fatal typhoid

if one parent has the gene for sickle cell..

you're less likely to get malaria

evolution

is caused by constant mutations