Double Helix Model (1)
Describe the double helix model of DNA
made of two strands that coil around each other
If a DNA molecule has 30 adenines how many thymines does it have.
30 thymines
Which direction is RNA synthesized in transcription?
5 to 3 direction
Daily Double1. How many bases make up a codon, and which type of RNA is it found on.
2. How many bases make up an anti-codon and which type of RNA is it found on
1. mRNA - 3 bases
2. tRNA - 3 bases
What is the purpose of DNA replication
When cell divides, each cell has an identical copy of the DNA ( assuming no mutations occur). S phase
Who were the three scientists that won the noble prize for the double helix model
watson, crick, and wilkins
What part(s) of the nucleotide make up the backbone of DNA what part(s) make up the interior of DNA.
Phosphate and sugar make up backbone (sides), bases make up interior.
What is the enzyme that performs transcription, and describe the purpose of the promoter
RNA polymerase, the promoter directs the RNA polymerase where to begin transcription
What is the difference between a frameshift and substitution mutation
Frameshift mutation a base is either added or subtracted. Substitution is when one base is exchanged for another base.
What is the major difference in DNA replication in eukaryotes and prokaryotes.
In eukaryotes since DNA is stored in the nucleus, takes place in the nucleus, while in prokaryotes takes place int he cytoplasm.
What are the building blocks of nucleic acids ( DNA and RNA and what are the three parts that make these up.
Nucleotides - phosphate, sugar ( deoxyribose in DNA, ribose in RNA), nitrogen bases
Daily Double - What are three differences between DNA and RNA
1. DNA has deoxyribose as a sugar, RNA ribose
2. DNA is two strands, RNA one strand
3. DNA has thymine, RNA has uracil
What are the two main differences in transcription between prokaryotes and eukaryotes
1. In eukaryotes transcription occurs in the nucleus, in prokaryotes cytoplasm
2. In prokaryotes RNA does not need to be processed in eukaryotes RNA is processed in the nucleus where introns ( do not code for proteins) are cut out, while exons ( code for proteins ) are joined together to make the mature RNA that will leave the nucleus and go to the ribosome for translation.
f a mRNA has 210 bases how many amino acids will the protein be ( assuming the last codon is the stop codon)
69 amino acids assuming last codon is a stop codon.
Describe the semi-conservative model of DNA replication.
Each newly synthesized DNA molecule has one old strand and one new strand
What were the two pieces of evidence watson and crick used to develop the double helix model
1. Photo 51
2. Chargraff's data
IF a DNA molecule has 1000 total bases, and has 200 many thymine bases how many guanine bases does it hace.
300
Describe the functions of the three types of RNA.
1. mRNA - carries the information from DNA to code for a protein
2. tRNA - carries the amino acid
3. rRNA - makes up ribosome
Explain the difference between a silent, missense, and nonsense mutation
silent mutation is a change in DNA sequence that results in no change in the amino acid sequence of the protein.
missense mutation is a change in DNA sequence that results in a change in the amino acid sequence of the protein.
nonsense mutation is when stop codon is introduced prematurely.
1.What are the four main enzymes involved in DNA replication and describe there functions.
2. What is the difference between the leading and lagging strand.
1. a. DNA Helicase - separates the two DNA strands by breaking the hydrogen bonds.
1. b. Primase - makes the primer
1. c. DNA polymerase - synthesizes DNA in the 5' to 3' direction.
1 d. DNA Ligase - seals the gaps between the Okazaki fragments.
2. Leading strand is synthesized continuously in the 5' to 3' direction in the same direction the DNA is opening up. Lagging strand is synthesized discontinuously in the 5' to 3' in the opposite direction the DNA molecule is opening up.
What is attached to the 5' end of the sugar of a nucleotide, what is attached to the 3' end of a sugar.
phosphate attached to 5' end, hydroxyl (OH) attached to 3' end.
500
In the hersey chase experiment.
1. Why were one batch of bacterial cells infected with bacteriophages labeled with S35 while the other batch was infected with bacteriophages labeled with P32.
2. In both experiments where was there a higher lower level of radioactivity and what information can be derived from this.
1. S35 labels proteins, P32 labels DNA
2. In bacterial cells infected with phages labeled S35 higher level of radioactivity outside the cell than inside the cell. In bacterial cells infected with phages labeled P32 higher level of radioactivity inside the cell than outside the cell. This suggests its DNA that is being injected from the bacteriophage into the host cell, and DNA carries instructions to make new phages, therefore DNA is the genetic material.
Describe in detail the steps of transcription.
1. Initiation - RNA polymerase binds to the promoter, hydrogen bonds between two strands are broken, therefore two DNA strands separate.
2. Elongation - RNA polymerase synthesizes RNA in 5 to 3 direction
3. Termination - RNA polymerase reaches the terminator sequence on the DNA, both the RNA polymerase and the newly synthesized RNA come off the DNA.
Describe in detail the steps of translation
1. Initiation - ribosome scans the mRNA until it reaches the start codon where the complementary anti-codon on the tRNA will match up with the complementary codon on the mRNA to deposit the first amino acid.
2. Elongation - ribosome moves to the next codon and the complementary anti-codon on the tRNA will match up with the complementary codon on the mRNA to deposit the next amino acid and ribosome will catalyze the formation of a peptide chain between these two amino acids. Ribosome moves to next codon and this process where another amino acid is deposited int he growing peptide chain as described above.
3. Termination - ribosome reaches stop codon, ribosome comes off the mRNA, polypeptide chain is released from the tRNA and now will fold into a protein.
Describe in detail the steps in order in DNA replication.
DNA helicase breaks apart the hydrogen bonds separating the two strands, SSBP bind to each strand, primer attaches to each strand, DNA polymerase synthesizes complementary strand in the 5'-3' direction, DNA ligase joins together the okazzaki fragments.