DNA Flashcards
daughter DNA molecules
each consisting of one parental strand and one new strand
separation of strand
parent strands separated
parent molecules
2 parent strands attached
Synthesizing a new DNA strand. Enzymes called DNA polymerases catalyze
the elongation of new DNA at a replication fork
the antiparallel structure of the double helix (two strands oriented in opposite directions)…
affects replication
DNA polymerases add nucleotides only to free 3’ end of a growing strand;
therefore a new DNA strand can elongate only in the 5’ to 3’ direction
along one template strand of DNA, the DNA polymerase synthesizes a ___________ continuously, moving toward the replication fork.
leading strand
to elongate the other new strand , called the lagging strand,
DNA polymerase must work in the direction away from the replication fork. the lagging s strand is synthesized as a series of segments call Okazaki fragments, which are joined together by DNA ligase
The proteins that participate in DNA replication form a large complex, a
DNA replication machine
The DNA replication machine is probably stationary during
the replication process
DNA polymerases proofed newly made DNA,
Replacing any incorrect nucleotides
in mismatch repair of DNA
repair enzymes correct error in base pairing
DNA can be damaged by:
chemicals radioactive emission, x-rays uv light and certain molecules (ex cigarette smoke)
a chromosome consists of a DNA molecules packed together with
proteins
the bacterial chromosome is a
double stranded, circular DNA molecule associated with a small amount of protein
Eukaryotic chromosomes
have linear DNA molecules associated with a large amount of protein
Chromatin
a complex of DNA and protein, and is found in the nucleus of eukaryotic cells
Histones
are proteins that are responsible for the first level of DNA packing in chromatin
30 nm fiber
interactions b/w nucleosomes cause the thin fibre to coil or fold into this thicker fibre
300 nm fiber
the 30 nm fiber forms looped domains that attach to proteins
Metaphase chromosome
the looped domains coil further
the width of a chromatid is 700 nm
The information content of DNA is in the form of
specific sequences of nucleotides
The DNA inherited by an organism leads to
specific traits by dictating the synthesis of proteins
