DNA,RNA,protein synthesis

1. DNA,RNA,protein synthesis

2. DNA Model / 3.1 • Using Chapter 11 in the textbook, answer the first three questions on the activity sheet. (5min.) • Create one model of 4 nucleotides as a table. Reminders: • Label the front of all pieces as you cut them out. • Build the individual nucleotides first before you connect them. • Ask for confirmation before gluing or taping (#2-4)

3. Deoxyribonucleic Acid. DNA is the code for making proteins. Proteins make you who you are  • Found in all cells!!!!!!!!!!! Only eukaryotes keep DNA in a nucleus. • What is it made of? The monomer of DNA is a nucleotide -deoxyribose, phosphate, and one base form a DNA nucleotide. • Draw one!

4. The 4 nucleotides of DNAIf you are building a DNA model that contains 4 unique nucleotides, how many sugars would you need? How many phosphates? How many bases?

5. Formation-Twisted Ladder or Double Helix • two nucleotides pair up in the middle to make a “rung” • Each “rung” must be the same size. • Therefore the base pairing rules are: • Adenine binds with Thymine • Guanine binds with Cytosine • These are held together by WEAK hydrogen bonds. • Strong bonds hold the sides together (sugar-phosphates)

7. Hierarchy • Genome-the entire set of an organisms DNA • Chromosome-Chromatid-Chromatin-Gene-Codon-Nucleotide • As you move through this list the size gets smaller.

8. DNA/RNA/Replication Diagram / 3.1 25 pts. • Read the sections labeled: DNA-The Double Helix Color diagram 1. Follow the colors in the reading. 10 min. • Read the section labeled: DNA Replication Color diagram 2. Follow all colors from the reading. 10 min. • Read the section labeled: Messenger RNA Color code diagram 3. Answer questions #1-18 in your notebook. 20 minutes.

9. DNA Replication • Copying the entire set of DNA in an organism. • When would an organism need to replicate the DNA in cells? • In preparation for mitosis • IN THE NUCLEUS: • Each single strand of DNA acts as a template for the new strand. • Enzymes control DNA replication. DNA polymerase. • 2 DNA strands now consists of a new and old strand. This is called semi-conservative replication.

11. RNA • Ribonucleic Acid – Read and highlight how RNA is different from DNA. • Color! • The monomer of RNA is a nucleotide. • ribose, phosphate, and one base form a RNA nucleotide. • Bases in RNA • Cytosine binds with Guanine • Adenine binds with Uracil (what??!!) • RNA is responsible for using the DNA code to create proteins. • RNA is single stranded most of the time so it can move in and out of the nucleus.

13. Types of RNA • mRNA (messenger)-takes the message for proteins out of the nucleus • tRNA (transfer)-transfers in the amino acids • rRNA (ribosomal)-makes the ribosome

14. Building A Protein • A gene is a sequence of nucleotide bases that code for a protein (a few hundred to thousands). • Nucleotides  codons  genes  proteins  traits • This process takes two steps: Transcription and Translation • DNA is transcribed (read) into RNA • RNA is translated into a protein

15. Transcription • DNA is split and the code is copied into mRNA nucleotides are added. • Transcription must occur because DNA contains the instructions for making proteins but it CANNOT leave the nucleus • Transcription is controlled by enzymes in the nucleus. • This strand of mRNA nucleotides breaks off and moves to the ribosomes for translation. • What is a codon????

17. Types of RNA • mRNA (messenger)-takes the message for proteins out of the nucleus • tRNA (transfer)-transfers in the amino acids • rRNA (ribosomal)-makes the ribosome

18. Translation • Once the DNA has been transcribed into mRNA now we need to translate (change) it into proteins. • Translation occurs at the ribosome. • tRNA anti-codons match with the mRNA codons and bring in amino acids. • Amino acids are connected by peptide bonds (=polypeptide) • This continues until the “stop” codon is reached (UAA, UAG, UGA)

24. Mutation Notes / 3.2 CTT TTA TAG TAG ATA CCA CAA AGG • Write the mRNA that would be transcribed from this gene. • What amino acids would form the protein coded by this gene? (use the chart) • What tRNA anticodons would bring the amino acids to the ribosome in translation?

25. Mutation Notes / 3.2 CTT TTA TAG TAG ATC CCA CAA AGG A mutation occurred that changed substituted one nucleotide. • Write the mRNA that would be transcribed from this mutated gene. • What amino acids would form the protein coded by this gene? (use the chart) • Is the protein the same?

26. Mutation Notes / 3.2 • Mutations result when a nucleotide or group of nucleotides is changed in DNA. • These “mistakes” can occur in replication, transcription or translation. • Mutations can be caused by heredity, mistakes, environmental factors such as UV, chemicals or X-rays. • Some mutations can be lethal. Some mutations are “silent”. Others may be beneficial (usually in smaller organisms)

27. Point mutations – only one nucleotide is substituted. These may OR may not be harmful if the new codon codes for the same amino acid on the chart. Ex. Sickle Cell Anemia • Frameshift mutations-mutation causing the codons to be inappropriately grouped or shifted. • Addition or Deletion • These mutations are harmful! THE CAT ATE THE BIG RAT

28. Summary • DNA mutations can happen during any process-replication, transcription or translation. • Mutations are not always harmful. • Frameshitfs are the most harmful mutations. • Any mutation is more harmful if it occurs early in the gene.