Transcript DNA - Mr. Lesiuk

co25
DNA is never found naked in normal cells, but instead
it is wrapped around spherical proteins called
Histones to form a chunkier rope-like material called
CHROMATIN
Fig. 25A
Fig. 25.2
Double ringed bases (Adenine and Guanine) are PURINES.
Single ringed bases (Cytosine and Thymine) are PYRIMIDINES
DNA Nucleotide
“Complimentary Base Pairing”
Very specific pairing takes place
HELPFUL
memory device
C to G with 3
T to A with 2
“T A 2”
Like “Tatoo”
Fig. 25.3
DNA is the
only molecule
that can copy
itself. Why is
that important?
Fig. 25.4
Fig. 25.8
DNA of a gene is copied into mRNA
that carries code outside the nucleus
of the cell
Fig. 25.7
Once the gene message is copied and carried outside of
the nucleus it can then be used as a guide to build
specific types of proteins.
Various structural and functional proteins (such as hair,
blood, enzymes, many hormones etc) are built by
assembling amino acids together in long chains
Fig. 25.6
Fig. 25.12a
Fig. 25.12b
Fig. 25.12c
Fig. 25.13
Fig. 25.17