DNA

Chapter 10

Biology

DNA

– DNA REGULATES ALL CELLULAR

ACTIVITY BY REGULATING PROTEIN

SYNTHESIS.

– DNA IS A SELF-REPLICATING

MOLECULE WHICH GETS PASSED ON

FROM ONE GENERATION TO THE NEXT.

EXPERIMENTS: STRUCTURE &

FUNCTION OF DNA

• FREDERICK GRIFFITH: 1928 – HE DISCOVERED THE PROCESS OF TRANSFORMATION IN BACTERIA.

-OSWALD AVERY: 1944 - HE PROVED THAT

DNA IS THE MOLECULE THAT CAUSES

TRANSFORMATION IN BACTERIA.

-ALFRED HERSHEY & MARTHA CHASE: 1953 – THE

GENETIC MATERIAL IS DNA.

• JAMES WATSON & FRANCIS CRICK:

1953 – THEY DISCOVERED THE

DOUBLE – HELIX WHICH MAKES UP

A DNA MOLECULE. THEY CREATED

A MODEL OF DNA.

GENE

• THIS IS THE NITROGEN BASE

SECTION OF A DNA MOLECULE

THAT CONTROLS PROTEIN

SYNTHESIS.

DNA IS A DIRECTIONAL

MOLECULE FOR EACH

HELIX. – DNA REPLICATES ITSELF IN A 5′ CARBON OF

SUGAR TO 3′ CARBON OF SUGAR

DIRECTION OF EACH HELIX. (sketch)

-EACH HELIX IS ANTIPARALLEL TO THE

OTHER ONE (sketch)

CHROMOSOME FORMATION

• DNA COILS AROUND PROTEIN

MOLECULES CALLED HISTONES.

• BEAD – LIKE NULCEOSOMES FORM.

• CHROMATIN FORMS WHEN

NUCLEOSOMES GATHER INTO 30

NANOMETER DIAMETER FIBERS.

• A CHROMOSOME FORMS WHEN THE

CHROMATIN COILS TOGETHER AND

THICKENS.

POLYMERASE CHAIN

REACTION (PCR)

• A GENE OR PIECE OF DNA CAN BE

COPIED MANY TIMES RAPIDLY.