Protein Synthesis DNA&RNA

DNA Deoxyribonucleic Acid Deoxyribonucleic Acid Shape - double helix - twisted ladder Shape - double helix - twisted ladder

DNA cont. Made up of three parts Made up of three parts A sugar molecule - deoxyribose A sugar molecule - deoxyribose A phosphate group A phosphate group A nitrogen base A nitrogen base Adenine Adenine Guanine Guanine Cytosine Cytosine Thymine Thymine

Bases Purines - 2 rings of carbon and nitrogen atoms Purines - 2 rings of carbon and nitrogen atoms Adenine Adenine Guanine Guanine Pyrimidines - 1 ring of carbon and nitrogen atoms Pyrimidines - 1 ring of carbon and nitrogen atoms Thymine Thymine Cytosine Cytosine

Purines

Complementary Base Pairing Nucleotides that normally pair together Nucleotides that normally pair together 2 Base-pairing rules 2 Base-pairing rules Cytosine bonds with guanine Cytosine bonds with guanine Adenine bonds with thymine Adenine bonds with thymine Base pairs connect by hydrogen bonds Base pairs connect by hydrogen bonds

The DNA Song to the tune of "Row, Row, Row your Boat We love DNA, made of nucleotides. Sugar, phosphate and a base bonded down one side. Adenine and thymine make a lovely pair, cytosine without guanine would feel very bare.

Replication of DNA Replication= process of copying DNA in the cell. Replication= process of copying DNA in the cell. 1. Two nucleotide chains are separated by helicase enzyme. (AKA replication fork) 1. Two nucleotide chains are separated by helicase enzyme. (AKA replication fork) 2. Hydrogen bonds within DNA are broken. 2. Hydrogen bonds within DNA are broken. 3. DNA polymerases attached to strands. 3. DNA polymerases attached to strands. 4. Complimentary DNA strands are formed. 4. Complimentary DNA strands are formed. 5. New strands bind with old strands resulting in two full strands of DNA. 5. New strands bind with old strands resulting in two full strands of DNA.

RNA Ribonucleic Acid Ribonucleic Acid Shape - Single helix Shape - Single helix

RNA

Three Type of RNA Messanger RNA (mRNA) Messanger RNA (mRNA) Carries genetic material from DNA in the nucleus to the cytosol. Carries genetic material from DNA in the nucleus to the cytosol. Transfer RNA (tRNA) Transfer RNA (tRNA) Hairpin shaped. Hairpin shaped. Binds directly to amino acids. Binds directly to amino acids. Ribosomal RNA (rRNA) Ribosomal RNA (rRNA) Most abundant type of RNA Most abundant type of RNA Assist in production of proteins Assist in production of proteins

RNA cont. Made up of three parts Made up of three parts A sugar molecule - ribose A sugar molecule - ribose A phosphate group A phosphate group A nitrogen base A nitrogen base Adenine Adenine Guanine Guanine Cytosine Cytosine Uracil Uracil

Purine or Pyridimine?

Pyridimine

Complementary Base Pairing 2 Base-pairing rules 2 Base-pairing rules Cytosine bonds with guanine Cytosine bonds with guanine Adenine bonds with URACIL Adenine bonds with URACIL

General Information One strand of the DNA double helix is used as a template One strand of the DNA double helix is used as a template DNA is only found in the nucleus DNA is only found in the nucleus Protein synthesis takes place in ribosomes. Protein synthesis takes place in ribosomes.

Breaking the Bonds RNA polymerase bumps into the promotor site of the DNA RNA polymerase bumps into the promotor site of the DNA Helicase is an enzyme used to unzip the DNA Helicase is an enzyme used to unzip the DNA Occurs inside the nucleus! Occurs inside the nucleus!

Breaking the Bonds cont. Messenger RNA (mRNA) is synthesized by RNA polymerase until a stop signal is reached. Messenger RNA (mRNA) is synthesized by RNA polymerase until a stop signal is reached.

After mRNA is Made Helix zips the DNA molecule as hydrogen bonds form Helix zips the DNA molecule as hydrogen bonds form mRNA leaves the nucleus mRNA leaves the nucleus

mRNA mRNA leaves the nucleus through pores in the nuclear membrane and travels to the cytoplasm mRNA leaves the nucleus through pores in the nuclear membrane and travels to the cytoplasm Every 3 bases make what is known as a codon Every 3 bases make what is known as a codon Look on page 195 of text Look on page 195 of text

1st 2nd2nd 3rd

Something to notice There is only one start codon. There is only one start codon. For translation to occur, mRNA must have AUG. For translation to occur, mRNA must have AUG. There are three stop codons. There are three stop codons. Translation will stop if mRNA reaches UAA, UAG or UGA. Translation will stop if mRNA reaches UAA, UAG or UGA.

Translation Ribosomes bind with the mRNA at the start codon (AUG) Ribosomes bind with the mRNA at the start codon (AUG) tRNA (transfer RNA) has an anticodon (three nitrogenous bases that are complementary to the codon on mRNA) that codes for the same amino acid. tRNA (transfer RNA) has an anticodon (three nitrogenous bases that are complementary to the codon on mRNA) that codes for the same amino acid.

Translation cont. tRNA finds the amino acid that the genetic code asks for and bring it to the ribosomes. tRNA finds the amino acid that the genetic code asks for and bring it to the ribosomes.

Translation What would the tRNA sequence be? What would the tRNA sequence be?

Translation cont. The ribosomes build peptide bonds connecting the amino acids to form a polypeptide. The ribosomes build peptide bonds connecting the amino acids to form a polypeptide.

Protein Elongation

Ending Translation At the end, the stop codon terminates translation At the end, the stop codon terminates translation The complete polypeptide is released from the ribosome. The complete polypeptide is released from the ribosome.

Termination of Translation What would the peptide sequence be? What would the peptide sequence be?

Summary of Translation

Proteins Synthesis DNA is “unzipped” DNA is “unzipped” mRNA is made and leaves the nucleus mRNA is made and leaves the nucleus tRNA takes the amino acids to the ribosomes tRNA takes the amino acids to the ribosomes Protein is made Protein is made