Download DNA

DNA
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Goals and Standards
After completing all activities and assignments in this unit,
students will be able to:
• Describe mitosis and meiosis and explain their importance.
• Construct and identify the parts of a model of a DNA molecule.
• Describe how DNA copies itself.
PA Science and Technology Standards covered in this unit:
• 3.1.7B Describe the use of models as an application of scientific or
technological concepts.
• 3.3.7C Know that every organism has a set of genetic instructions
that determines inherited traits.
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Vocab: DNA, gene,
replication
• DNA – Deoxyribonucleic acid – a chemical in the
nucleus of cells that codes and stores genetic
information.
• Gene – A segment of DNA on a chromosome
that directs the making of certain chemicals,
controlling traits that are passed to an offspring
• Replication – creation of new exact copies of
DNA to be used in newly made cells
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Vocab: Mutations
Mutation – a mistake that is made when DNA is
copied. This may or may not show a problem in
the individual
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Vocab: Mitosis,
chromosome, asexual and
sexual reproduction
• Mitosis – process that divides the nucleus to
make 2 identical cells
• Chromosome – threadlike strands of DNA in the
nucleus that carry the information for all the
characteristics of an organism
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Vocab: Meiosis,
fertilization, RNA
• RNA – ribonucleic acid – similar to DNA,
but one stranded. Leaves the nucleus to
make proteins at the ribosomes.
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Vocab: Transcription,
translation, amino acid, protein
• Transcription – DNA is copied into RNA
• Translation – RNA is copied into proteins
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What does DNA look like?
T
A
C
Sugar
G
Thymine
T
A
G
C
Phosphate
Group
G
C
A
T
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T
A
Adenine
Guanine
Cytosine
DNA Model Notes
Characteristics of DNA:
1. The sides or “handrails” of the DNA “ladder” are made of
sugar and phosphate molecules.
2. The “stairs” are made of molecules called
nitrogenous bases.
3. The 4 nitrogenous bases are:
Adenine thymine cytosine guanine
4. The nitrogenous bases always match up like this:
Adenine and thymine
Cytosine and guanine
5. The two strands of DNA are complimentary to each other.
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Materials Key
Material
Beads
DNA Structure
Pipe Cleaners
Serve to anchor
everything else together
Phosphate groups
Straws
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Blue = Adenine
Yellow = Thymine
Green = Guanine
Purple = Cytosine
Red = Sugar
Making your DNA model
First, build
a half
strand of
DNA that
looks like
this.
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Then, match
the
nitrogenous
bases and
build the
other half of
the DNA
strand.
Interphase: When the cell is doing
its work
Cell membrane
DNA – 2 copies
Cytoplasm
Nucleus
Nuclear membrane
Centrioles
Packet page # 8 – top left box
Prophase – DNA starts to appear as
chromosomes
Chromosomes
Nuclear envelope dissolving
Spindle
Centrioles
Packet page # 8 – top right
Metaphase: Chromosomes line up
Chromosomes lined up on equator of cell
spindle
centriole
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8 – middle left
Anaphase – Spindle pulls the copies
of the DNA to opposite poles
Packet page # 8 – middle right
Telophase – New nuclear
membranes start to appear
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8 – bottom left
Cytokinesis – 2 separate, identical
cells
Packet page # 8 – bottom right
Meiosis vs Mitosis
Meiosis
1. 2 divisions of
A. Involve
the nucleus
chromosomes
2. Makes sperm
B. Use prophase,
and egg cells
metaphase,
only
anaphase and
3. New cells have
telophase
½ the number of
Chromosomes as
original
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Mitosis
1. 1 division of
the nucleus
2. Makes all other
types of cells
3. New cells are
identical to
original