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Chapter 6
Reproduction and Gene Function
Asexual Reproduction: A Result of
Mitosis
• Asexual reproduction is
reproduction by mitotic
cell divisions.
• An amoeba is an
organism that
reproduces asexually.
• An amoeba simply
grows and then divides
in to two organisms!
Asexual Reproduction
• Budding
• Yeast cells reproduce
asexually by budding.
• A bulge forms on the
cell and it eventually
breaks off in the form of
a new yeast cell.
• This is by mitosis.
Asexual Reproduction
• Regeneration
• Some worms have the
ability to reproduce
through regeneration.
• If cut in two pieces,
both pieces will
eventually grow into
new worms.
Asexual Reproduction
• Spores
• Many organisms produce spores by mitosis.
• Mold does this.
How Genes Function
• In 1953, James Watson
and Francis Crick
worked out a model for
the structure of DNA!
• DNA stands for
Deoxyribonucleic Acid.
• Their model looked like
a twisted ladder.
• The ladder contains
units called nucleotides.
How Genes Function
• There are three parts to a
nucleotide:
• The sugar
• The phosphate
• The base
• There are four different
bases:
• Adenine
• Thymine
• Guanine
• Cytosine
DNA Structure
• The sugars and
phosphates make up
the sides of the ladder.
• The bases make up the
rungs.
DNA Replication
• When a cell divides, the
DNA needs to be copied
so that each new cell
has a full set of DNA.
• This process is called
Replication.
• A new cell is able to
make any missing part it
may need as long as it
has a full copy of DNA.