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DNA. What is the shape of DNA?. What is the shape of DNA?. Double Helix. What are the parts of the nucleotide?. What are the parts of the nucleotide?. Phosphate Sugar Base. What is the DNAs job?. What is the DNAs job?. Molecule that stores genetic information in all organisms.
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What is the shape of DNA? • Double Helix
What are the parts of the nucleotide? • Phosphate • Sugar • Base
What is the DNAs job? • Molecule that stores genetic information in all organisms
What kind of bonds are there in DNA? • Covalent-appear between the phosphate and the sugar (deoxyribose) • Hydrogen- appear between the nitrogen bases
What are the four bases of DNA? • Thymine • Adenine • Cytosine • Guanine
What is the base pairing rules of DNA? • A=T • C=G
What is the difference between a pyrimidine and a purine? Pyrimidine- Single ring Purine-Double ring
When do cells replicate? • During S Phase of the cell cycle
What is made during replication? • 2 strands of DNA
Why is replication needed? • Replication assures that every cell has a complete set of identical genetic information
What molecules are involved in replication? • DNA molecules • DNA polymerase
Describe the steps in the process • 1. Enzymes begin to unzip the the double helix along the chromosome. • 2. Floating nucleotides pair with the bases on the template strands. DNA polymerases bond the nucleotides together. • 3. Two identical molecules of DNA result. Each molecule has one strand from the original molecule and one new strand.
Why is replication semi conservative? • One strand of the DNA came from the original molecule and another part is newly formed
Where does transcription happen? • Transcription happens in the nucleus as DNA converts into an intermediate molecule called RNA
What is made? • mRNA is made
What molecules are involved? • DNA • Messenger RNA (mRNA) • RNA polymerase
Why is it needed? • To create RNA which will make a protein.
Describe the steps of the process • 1. A transcript ion complex of RNA polymerase recognizes a start of a gene and begins to unwind a segment of DNA • 2. RNA polymerase use one strand of DNA as a template. G pairs with C and A pairs with U • 3. RNA separates from the DNA template
What is a “codon”? • Three nucleotide sequence
What do they code for? • Amino acids
What is translation? Where does it happen? • A process that converts or translates mRNA message into a polypeptide • It happens in the cytoplasm on a ribosome.
How is the code read? • In units of three nucleotides left to right.
What are the steps for translation • 1. Exposed codon attracts a complementary tRNA molecule bearing an amino acid. The tRNA anticodon pairs with the mRNA codon • 2.Ribosomes form a peptide bond with two amino acids and break the bond with the first tRNA and its amino acid • 3. Ribosome pulls the mRNA strand the length of the codon. The first tRNA shifts into the exit site where it leaves the ribosome and returns to the cytoplasm to recharge. The first site is empty , exposing the next mRNA codon.
What is produced at the end? • Protein