2.  Replace old cells  Growth  Repair cuts/ wounds  Reproduction

3.  DNA must replicate, or make an exact copy of itself to put into new cells. 1 DNA2 DNA DNA Replication

4.  1: DNA double helix unwinds.

5.  2: Hydrogen bonds break and strands begin to unzip.

6.  3: Free nucleotides pair up with nucleotides on parent strand to form a complementary strand.

7.  At the end of replication, two IDENTICAL daughter strands of DNA have been formed!

8.  Each new strand pairs up with an old strand two produce two DNA molecules each containing one parent (old) and one daughter (new) strand.

9.  After DNA is replicated, a cell splits to form two cells that each get one copy of the DNA!

11.  Riboonucleic acid  RNA is used to make a temporary copy of the information contained in the DNA of an organism.

12.  Messenger RNA (mRNA)  Transfer RNA (tRNA)  Ribosomal RNA (rRNA)

13.  Single helix  Single strand  Backbone of sugar, phosphate  Nucleotides: ◦ Adenine ◦ Guanine ◦ Cytosine ◦ Uracil

14.  DNA is in the nucleus of the cell BUT  Proteins are made in ribosomes in the cytoplasm

15.  Instructions from DNA need to be carried to ribosomes so proteins can be made.  Why would it be a bad idea to send the DNA to the ribosomes? DNA Protein Manufacturing

16.  Each cell only has one copy of DNA, so it has to be protected in the nucleus.  Thousands of mRNAs can be made from a DNA template strand, but DNA is only replicated to make a new cell.

19. DNA mRNA transcription

20.  To make a copy of something  Examples: ◦ Rewriting or typing an old documents ◦ Typing the lyrics to a song ◦ Taking notes from a PowerPoint!

21.  DNA contains all the information for making the proteins that make up our bodies.  DNA never leaves the nucleus of the cell. If this is true, then how does the rest of the cell get information from the DNA?

22.  1: DNA unwinds  2: DNA unzips

23.  3: RNA nucleotides are combined by RNA polymerase to form messenger RNA (mRNA) strand

24.  4: DNA rezips and winds back up

25.  mRNA leaves the nucleus through a nuclear pore and travels to a ribosome

26.  Proteins are made from the mRNA!

27.  DNA contains the instructions for making proteins  The instructions are in code  The code is based on the sequence of amino acids—each protein has a particular sequence  Each amino acid has a 3-nucleotide code (like AGA or GCC)  The code is transferred to mRNA

29.  3 bases of mRNA= 1codon = 1 amino acid

30.  There are 20 amino acids.  The hundreds of thousands of proteins are made with different sequences of amino acids—300 long or more

31.  Each codon is specific to an amino acid.

32.  One sequence ALWAYS tells a ribosome where to start an amino acid chain.  AUG codes for met (methionine)  Every amino acid chain starts with a methionine in humans. AUGAUG

33.  Tells a ribosome where to stop reading a strand of mRNA  There are 3 stop codons: UAA, UAG, and UGA.

35.  What amino acid is coded by: ◦ GCU: ◦ GAA: ◦ CUA: ◦ AUU: ◦ UCG:

36.  What amino acid is coded by: ◦ UGG: ◦ AUA: ◦ GUC: ◦ GAA: ◦ UUU:

38. mRNA protein translation

39.  In a ribosome

40.  Transfer RNA- bring amino acids to ribosome in order to make a protein made of amino acids

41.  Each 3 base sequence of mRNA is known as a codon and is specific for a particular amino acid.

42.  1. tRNA molecule finds and attaches to the specific amino acid it is designed to recognize Steps to Translation – tRNA attaches to specific amino acid

43.  2: tRNA molecule (with its amino acid) attaches to mRNA codon

44.  2: A peptide bond is formed between amino acids.

45.  3: tRNA molecule exits the ribosome. The ribosome shifts down the mRNA.

46.  T: tRNA and amino acid  A: Attachment  P: Peptide Bond  E: Exit

47.  A chain of amino acids= protein!

48.  Protein gets shipped to a part of the cell to do a specific job.  mRNA is broken down into bases that can be used to make new mRNA or translated again to make another protein