Chapter 10 Flashcards
Describe the meaning of the term hereditary info. How is DNA involved
It means that genetic information is passed down from parents to offspring. DNA is involved because in replication, one strand is parental and one strand is a new daughter strand. The model template is a parental strand.
Explain the experiment that was used to discover that DNA is, in fact, genetic material
Hershey and Case: used radioactive sulfer to dye protieins and radioactive phosporus for DNA
Showed that phages rise since its lighter than virus
Describe the structure of DNA and how that structure is able to meet the needs of the organism for hereditary transfer from generation to generation
The structure of DNA is a double helix, and when it is pulled apart by DNA helicase, the parental strand is used in replication which is how it is used for hereditary transfer.
Describe the nucleotides of DNA and RNA and how they are arranged. Which nitrogenous base bonds with which? How do DNA and RNA differ? how are the simular?
They both have the 3 essential building blocks (phosphate group, 5 carbon sugar, and nitrogenous bases), but RNA has ribose sugar while DNA is deoxyribose sugar. The base A always bonds with T (or U on RNA), and the base C always bonds with G. They are different because RNA is 1 strand whilde DNA is 2, RNA has uracil and DNA has thymine, and RNA is ribose sugar (with oxygen) and DNA is deoxyribose (without oxygen).
Explain how watson, crick, and franklin figured out the structure of DNA
They used x-ray diffracted images to observe the double helix shape.
Why does DNA have to duplicate in order of Mitosis to occur?
each daugther cell needs its own set of DNA
Define semiconservative replicaiton. Explain the concept of the DNA template
Semicon: Reuslting strand is half parent/half daugther.
When copying, strands untwist and split
The Parent strand is what decides how the daugther will look (template)
What is occuring at the origins of replication? Why are their multiple origins?
The origin of replication is where the DNA replication begins. There are multiple origins because eukaryotic DNA is much larger than prokaryotic DNA, so it needs to replicate much faster.
What is meant by a 3’ or 5’ end of DNA? How are they important in the process of replication and transcription?
This means that the 3’ end is where there is an OH molecule (hydroxyl group) and the 5’ end is where there is a phosphate group attached to the 5th carbon in the sugar ring.
Describe the function of DNA helicase
Enzyme that attaches to DNA and seperates parental strands
Opens DNA at replication bubble
Describe the function of DNA polymerase
Enzyme adds nucleiotides only at the 3’ end
Daugther cells elongates 5’-‘3 direction
What is meant by the statement: “DNA genotype is expressed as proteins that provide the molecular basis for phenotypic traits”?
DNA codes for proteins to determine phenotype instructions in form of RNA
Explain how the gentoype is expressed as phenotype
Because a genotype codes for a trait, while a phenotype is what is expressed.
Steps that occur when a gene is translated into a protein
mRNA attaches to rRNA, rRNA tells tRNA which amino acids to bring. rRNA makes peptide bonds.
What is meant by one gene=one protein? Why is one gene=one polypeptide more accurate
Because proteins can be made up of more than one polypeptide chain
Defien transcription and translation
Transcription: Transfer of genetic material from DNA to RNA
Translation: Transer of genetic info from RNA to Protein
Explain what happens during DNA replication initiation, elongation, and termination
Initiation begins at the origin, and the parental strands are separated and form the replication bubble.
Elongation is where DNA polymerase starts to write on the 5’ to 3’ direction to write the daughter strand.
Termination is when the replication reaches the end and the new strand is proofread
what exactly is a gene?
A gene is a piece of DNA that contains the information necessary for the cell to make one protein
What is the Triplet code? What is a codon? What info do condons confer?
triplet: 3 bases are read at a time
Codon: 3 RNA bases that specify for an amino acid
Confer to amino acids
Define start and stop codons
Sequence of codons that signals the rRNA to stop translating to tRNA
Explain how tRNA is invloved in teh construction of a polypeptide
brings anticodon to build amino acid chain
Define an anticodon and how it works
An anticodon is a set of 3 complementary bases to mRNA that is on one end of tRNA.
Describe rRNA and its role in translation
Ribosome RNA: Makes polypeptides and positions the mRNA and RNA
What is mutation, how does it occur and what are the 4 types
Any change in the amino acid sequence of DNA
Happens when DNA Polymerase makes a mistake
Silent (no change),
Missease: (Change in aa (EX: Sickle cell))
Nonsense: Changes an aa into a stop codon
Base insertion/deletion
Define the term “Reading frame”
Area of mRNA being read
The complimentary bases of DNA are located on the _____ of the helix, with the sugar-phosphate backbone on the inside.
inside
The strand of DNA that is being replicated away from the replication fork and in short fragments (Okazaki fragments) is called the _________.
lagging strand
If a DNA sample contains 13% adenine, it will contain __% cytosine.
37%
T/F? Protein synthesis may still occur without ribosomes.
FALSE
T/F? Translation is the first step in the production of a protein from the information coded by DNA
FALSE
T/F? Transcription is the process that synthesizes mRNA.
FALSE
T/F? In eukaryotes, the initial mRNA transcript is always found in the nucleus.
TRUE
Who were the 2 scientists that performed an experiment on bacteriophages?
Alfred Hershey and Martha Chase
What are bacteriophages (phages)?
Viruses that can cause disease in bacteria.
What radioactive isotope labled the DNA?
Phosphorus
What radioactive isotope labled the Proteins?
Sulfur
Why did Hershey and Chase use sulfur and phosphorus?
Phosphorus was used to mark the DNA because DNA contains phosphorus but not sulfur, and the sulfur was used to mark proteins because the proteins contained sulfur but not phosphorus.
On the first run of the test, was the color showing up on the top or the bottom of the centrofuge?
Top
On the first run of the test, was there sulfur found in the bacteria?
No
On the second run of the test, was the phosphorus found in the bacteria?
Yes
What do the second results mean?
The bacteria cells were now green, which meant that the DNA is what entered the bacteria cells and proved that DNA was the genetic material used to replicate inside of and enter bacteria.
What two nitrogenous bases are single ringed?
Thymine (Uracil) and Cytosine
What are the single ringed structures on DNA called?
Pyridimines.
Which two nitrogenous bases are double ringed?
Adenine and Guanine
What are the double ringed structures on DNA called?
Purines
___ pairs with thymine and ___ pairs with cytosine.
Adenine, Guanine