12.3 Flashcards
Each strand of the DNA can be used to make the other
strand, the strands are said to be
complementary
Why do DNA replication occurs before mitosis
so that each of the
daughter cells resulting from mitosis contains the full
amount of genetic material.
DNA replication occurs during the
….
phase of the cell cycle
S
replication
Before a cell divides, it duplicates its DNA in a copying
process called
During replication, the DNA molecule separates into two
strands and then produces
two new complementary
strands following the rules of base pairing
Each strand of the double helix of DNA serves as a
template for the new strand.
If one strand that has the base sequence TACGTT it
produces the new complementary strand that has the
base sequence
ATGCAA
The result is two DNA molecules identical to each other
Each DNA molecule has
one old strand and one new
strand
DNA polymerase
is an
enzyme that joins individual nucleotides to produce a new
strand of DNA
Telomeres
the tips of eukaryotic chromosomes
What do telomerase do and why
Telomerase adds short, repeated DNA sequences to
telomeres as the chromosomes are replicated in dividing
cells such as those found in an embryo, to prevent genes
from being lost during replication.
In eukaryotic cells replication may begin at dozens or
even hundreds of places on the DNA molecule
proceeding in both directions until each chromosome is
completely copied
Who has a greater number of replication forks on
the DNA strand
Eukaryotes
When does the DNA replication start
DNA replication does not start until regulatory proteins
bind to a single starting point on the chromosome
Who triggers the beginning of the S phase
Proteins
