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The synthesis of RNA under the direction of DNA is called __________ and takes place in the cell’s __________. The synthesis of protein under the direction of __________ is called __________ and takes place in the cell’s __________.
transcription, nucleus; RNA, translation, cytoplasm
Within a population of butterflies, the color brown (B) is dominant over white (b). 40% of butterflies are white. What percentage of butterflies are heterozygous? What is the frequency of homozygous dominant individuals?
Percentage heterozygous-> 2pq= 47%.
Frequency homozygous genotype-> P2= 0.14
What does 2pq stand for?
Frequency of heterozygous genotype (Aa).
What does q^2 stand for?
Frequency of homozygous recessive genotype
What does P^2 stand for?
Frequency of homozygous dominant genotype (AA).
Can you directly know the alleles from phenotype (mendelian genetic/inheritance)?
No, because phenotype won't show you heterozygous genotype.
Which ones are matching (the same): phenotype, genotype, traits, genes?
Phenotype-Traits, Genotype-Genes
What are adaptations?
Inherited characters that enhance an organism's ability to survive and reproduce.
Define evolution.
Evolution is the changing of traits in a population due to natural selection across many generations.
What are the key points to evolution?
Individuals do not evolve (population over generations).
Natural selection can only amplify or diminish heritable traits.
Evolution is not goal based.
What is the mechanism of evolution?
Natural selection.
Where does translation take place?
Ribosome.
Describe the first phase of transcription.
RNA polymerase attaches to a DNA strand and separates the two strands.
What is a promoter and what binds to it?
A promoter is a specific nucleotide sequence in DNA that is at the start of the gene. It binds to RNA polymerase and is where transcription begins.
What is the structure of DNA?
A double helix.
What are DNA and RNA made of?
Long chains of chemical units called nucleotides.
What are the 4 types of nucleotides that make up DNA?
Adenine, cytosine, guanine, thymine.
How are the individual nucleotides in an DNA or RNA molecule joined together?
By covalent bonds between sugar of one nucleotide and phosphate of the next.
Explain what the sugar-phosphate backbone is.
A chain of sugar and phosphate to which nitrogenous bases are attached.
List the three components of a nucleotide.
Nitrogenous base, a sugar, a phosphate group.
How do the 4 nucleotides differ from each other?
They differ in structure, half are single rings, while the other half are double rings.
What are the 2 differences between RNA and DNA?
RNA’s sugar is ribose rather than deoxyribose and it has uracil instead of thymine.
Who was credited with the discovery of the structure of DNA?
Watson and Crick
What was the role of Rosalind Franklin in the discovery of the structure of DNA?
She made an x-ray image of DNA showing a double helix.
What DNA base pairs with what DNA base?
Cytosine pairs with guanine. Adenine pairs with thymine.
What does Chargaff’s rule state?
That cytosine always pairs with guanine and adenine pairs with thymine. Also that the corresponding pairs will be the same percentage out of the nucleotides.
Given that the DNA of a certain fly species consists of 27.3% adenine and 22.5% guanine, use Chargaff’s rule to deduce the percentages of thymine and cytosine.
Thymine would be 27.3% and cytosine would be 22.5%.
How can we visualize the structure of DNA?
As a rope ladder with wooden rungs twisted into a spiral.
What do the sides of the ladder represent in a real DNA molecule?
The sugar phosphate backbones.
What do the rungs of the ladder represent in a real DNA molecule?
Pairs of nitrogenous bases joined by hydrogen bonds.
Who else received the Nobel prize along with Watson and Crick?
Maurice Wilkins
Why did Rosalind Franklin not receive the Nobel prize along with Watson, Crick, and Wilkins?
She died of cancer a few years prior.
For the below sequence of DNA provide the complimentary DNA strand: A G T T A C G C A T C G G C A T
TCAATGCGTAGCCGTA
What is the semiconservative model of replication?
The model for DNA replication that shows that half the parental molecule is maintained.
Where in the cell does DNA replication begin?
At the origin of replication.
What is the origin of replication?
Short stretches of DNA having a specific sequence of nucleotides where DNA replication begins.
What role does DNA polymerase play in DNA replication?
They help link nucleotides to growing strands so that they have the correct orientation.
With your knowledge of DNA, explain what a genotype is.
The information contained in the sequence of nucleotide bases in DNA.
With your knowledge of DNA, explain what a phenotype is.
The physical traits that the genes direct the proteins to create.
What is the link between the genotype and phenotype?
Proteins
Do genes directly build proteins? If not, then explain how genes build proteins.
Genes dispatch instructions (RNA) which programs protein synthesis.
What are the two main stages of protein synthesis (gene expression)?
Transcription and translation.
Explain transcription.
Synthesis of RNA under direction of DNA.
Explain translation.
Synthesis of proteins under direction of RNA.
What is the flow of information from gene to protein based on?
A triplet code: the genetic instruction for the amino acid sequence of a polypeptide chain in DNA and RNA as a series of nonoverlapping 3 base “words”.
Describe a codon.
A 3-nucleotide sequence that specifies amino acid or polypeptide signal; genetic code.
Below is a short DNA template. Below it, assemble the complementary mRNA strand:
A C G A C C A G T A A A
UGCUGGUCAUUU
What does it mean when we say the genetic code is redundant but not ambiguous?
The genetic code has many redundancies like words in the human language. But this is not a bad thing because our DNA is changing every day. So these redundancies keep our DNA from mutating and causing genetic diseases most of the time.
What does it mean when we say the genetic code is nearly universal?
Because all living organisms go through the same process which means that these rules can be universal.
Translate the RNA sequence CCAUUUACG into the corresponding amino acid sequence.
GGUAAAUGC
Where does transcription take place within the cell?
Transcription takes place in the cytoplam
What role does RNA polymerase play in transcription?
RNA polymerase is the only enzyme used to transcribe DNA to RNA. First it separates the strands of DNA and then corresponds that base with its complementary RNA base.
Describe the second phase of transcription.
RNA polymerase moves down the DNA strand joining complimentary bases between DNA and mRNA to make a singlet strandof mRNA.
Describe the third phase of transcription.
RNA polymerase detaches from DNA by using the terminator, the mRNA strand drifts free.
What type of RNA molecule is transcribed from DNA?
An mRNA molecule. (Messenger RNA)
What is Chargaff's rule?
A rule that shows which bases pair with each other.
What is the building block and structure of DNA?
DNA is a double helix made up of nucleotides.
What is a nucleotide made of?
A nitrogenous base (adenine, cytosine, thymine, guanine), a phosphate group, and a deoxyribose(sugar)
Why does DNA goes from a double helix to Chromatin
The double helix form can be fragile because the nucleotides are held together by hydrogen bonds, so by condensing it to chromatin, it's not as long and breakable.
Why are nucleotides joined together (adenine and thymine for example) by hydrogen bonds?
They are joined by hydrogen bonds because hydrogen bonds are weaker, and weaker bonds are needed so that information can be shared through DNA replication, transcription and translation, and cell division.
How is RNA different from DNA?
Use of ribose, uracil in place of thymine, single strand, no use of hydrogen bonds.
How does every organism use the same DNA, without having the same genotype?
Because organisms use different nucleotide sequences.
What is DNA replication used for?
Cell division and protein synthesis.
How does DNA replication make use of the semiconservative model?
By keeping one original strand and making a new complementary strand, to make the replica.
What is needed for DNA replication?
Helicase and DNA polymerase.
Describe the replication process.
2 strands separate to give access to bases.
Enzyme called helicase breaks the hydrogen bonds between the nucleotides.
This creates a replication fork
Helicase makes use of replication bubbles to break bonds quicker.
After helicase, DNA polymerase creates a new complementary strand (replicates both new strands at same time).
Creates 2 identical copies.
What is the origin of replication?
A sequence of DNA bases that tells helicase to start.
What are the 2 parts of protein synthesis?
Transcription and translation.
What is gene expression?
The use of the genetic information in DNA to make proteins.
What is the central dogma of biology?
DNA->RNA->Protein
What is transcription (short answer)?
The process of going from DNA to RNA.
What is translation (short answer)?
Going from RNA to protein.
What is transcription (long answer)?
Genetic information encoded in DNA is transferred to an mRNA molecule.
What is translation (long answer)?
The process by which the genetic message in mRNA is deciphered.
Why create an mRNA?
So that there is less mistakes and damage on the way to the ribosome.
What is RNA polymerase?
An enzyme that attaches to the DNA and separates the 2 strands during transcription.
What is used to tell the RNA polymerase to attach/begin?
Promotor
Describe the process of transcription.
RNA polymerase attaches to the DNA molecule.
RNA polymerase moves down the DNA strand, joining complementary bases between DNA and RNA, making a strand of mRNA.
mRNA detaches and drifts free.
What is the genetic code?
It converts the language of RNA into the language of protein (AA).
Described what caused Darwin to question the beliefs about life.
He went on a voyage to the Galapagos islands and studied some finches. He noticed that the finches varied in beak sizes and shoes, even though they were the same finches from the coats of the mainland (same environment). This made him question the idea that organisms were unchanging in the same environment.
Why aren't organisms identical to parents?
Because of sexual reproduction, crossing over, and the Law of Independent Assortment.
What two major ideas did Dawin have, to answer his questions?
Descent with modification and natural selection.
What is descent with modification?
The idea that all prescient day species arose from ancestors.
What is natural selection?
The idea that certain individuals survive and reproduce better because of particular trait/s, than those without.
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