Packet page # DNA

Packet page # 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 C Know that every organism has a set of genetic instructions that determines inherited traits.

Packet page # 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 1

Packet page # Vocab: Mutations Mutation – a mistake that is made when DNA is copied. This may or may not show a problem in the individual 1

Packet page # 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 1

Packet page # Vocab: Meiosis, fertilization, RNA RNA – ribonucleic acid – similar to DNA, but one stranded. Leaves the nucleus to make proteins at the ribosomes. 1

Packet page # Vocab: Transcription, translation, amino acid, protein Transcription – DNA is copied into RNA Translation – RNA is copied into proteins 1

Packet page # What does DNA look like? A A A T T C G C G T T A C G Sugar Phosphate Group Thymine Adenine Guanine Cytosine 4

Packet page # 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 to each other. DNA Model Notes complimentary 5

Packet page # Materials Key MaterialDNA Structure Beads Blue = Adenine Yellow = Thymine Green = Guanine Purple = Cytosine Red = Sugar Pipe CleanersServe to anchor everything else together StrawsPhosphate groups 5

Packet page # Making your DNA model First, build a half strand of DNA that looks like this. Then, match the nitrogenous bases and build the other half of the DNA strand. 6

Packet page # Interphase: When the cell is doing its work Cell membrane Cytoplasm Centrioles DNA – 2 copies Nuclear membrane 8 – top left box Nucleus

Packet page # Prophase – DNA starts to appear as chromosomes Chromosomes Nuclear envelope dissolving Spindle Centrioles 8 – top right

Packet page # Metaphase: Chromosomes line up Chromosomes lined up on equator of cell spindle centriole 8 – middle left

Packet page # Anaphase – Spindle pulls the copies of the DNA to opposite poles 8 – middle right

Packet page # Telophase – New nuclear membranes start to appear 8 – bottom left

Packet page # Cytokinesis – 2 separate, identical cells 8 – bottom right

Packet page # Meiosis vs Mitosis Mitosis 1.1 division of the nucleus 2.Makes all other types of cells 3.New cells are identical to original Meiosis 1.2 divisions of the nucleus 2.Makes sperm and egg cells only 3.New cells have ½ the number of Chromosomes as original A.Involve chromosomes B.Use prophase, metaphase, anaphase and telophase