Some genes are continually expressed, whereas the expression of most genes is regulated, commonly at the level of transcription. At the initiation of transcription, the TATA-binding protein (TBP) provides access to the DNA strand to be transcribed.
Eukaryotic transcription does not start at a consensus sequence. b. Eukaryotic transcription does not require an initiation complex. c. Eukaryotic transcription and translation do not take place at the same time. d. Eukaryotic transcription does not require a termination sequence.
It depends on the gene. b. No, the rho protein is essential. c. Transcription termination is not required. d. Yes, the rho protein is not involved in transcription. Dennis H. Which feature of promoters can be found in both prokaryotes and eukaryotes? a. GC box Dennis H.
The range allows for interpersonal and small group differences that are influenced by specific environments, but still gives us important information about the differences in people’s traits. The interactions between your genes and your environment are especially important during your early development.
Is there a way to tell how much of an influence genes have on a behavior? Scientists can look at the influence of genes on behavior by using a mathematical formula called a heritability estimate. Heritability estimates give information about how much of an impact genes have on a behavior in a certain environment.
Their genes could tell their body to: increase the size of their fat cells or dictate how they use fat in their body.
If we look at the athletic ability of Jennifer’s neighbors, the heritability estimate is closer to 1 because their experiences in financially well off environment have enabled their athleticism genes to be expressed.
The athletic ability of Karen and her neighbors is decreased and the heritability of athleticism is closer to 0, because their experiences in a financially poor environment have inhibited genes associated with athleticism. On the other hand, Jennifer and her neighbors eat plenty of healthy foods are well nourished.
Karen’s eating and physical activity habits enhance the expression of her genes for obesity. Flowchart of two twins demonstrating how their environment (the food they eat) influences their genetics which determines whether they will be obese.
In some situations, genes play a larger role in determining your behavior; in other situations, environment plays a larger role in influencing your behavior . If you had a whole different set of experiences over your lifetime your genes may be expressed in different ways, and you may behave differently than you do now.
release chemicals (like hormones) which control hunger and appetite. influence behavior as Jennifer and Karen interact with their environment. For example, if Karen begins to gain weight, she may seek out fewer opportunities to exercise because going to the gym makes her feel uncomfortable.
Explain the initiation of transcription in prokaryotes. Include all proteins involved.#N#a. In prokaryotes the polymerase is composed of five polypeptide subunits, two of which are identical. Four of these subunits, denoted α, α, β, and β ′ comprise the polymerase core enzyme. The fifth subunit, σ, involved only in transcription initiation. The polymerase comprised of all five subunits is called the holoenzyme.#N#b. In prokaryotes the polymerase is composed of four polypeptide subunits, two of which are identical. These subunits, denoted α, α, β, and β ′ comprise the polymerase core enzyme. There is a fifth subunit that is involved in translation initiation. The polymerase comprised of all four subunits is called the holoenzyme.#N#c. In prokaryotes the polymerase is composed of five polypeptide subunits, two of which are identical. Four of these subunits, denoted α, α, β, and β ′ comprise the polymerase holoenzyme. The fifth subunit, σ, is involved only in transcription initiation. The polymerase comprised of all five subunits is called the core enzyme.#N#d. In prokaryotes the polymerase is composed of five polypeptide subunits, two of which are identical. Four of these subunits, denoted α, α, β, and β ′ comprise the polymerase core enzyme. The fifth subunit, σ, is involved only in termination. The polymerase comprised of all five subunits is called the holoenzyme.
Crick and coworkers (1961) used a method developed by Benzer to induce mutations in the DNA of a virus by the insertion of a single nucleotide. The mutant could not infect the bacterium Escherichia coli and neither could viruses with a second insertion of a second DNA nucleotide.
In your own words, describe the difference between ? -dependent and ? -independent termination of transcription in prokaryotes.#N#a. Rho-dependent termination is controlled by rho protein and the polymerase stalls near the end of#N#the gene at a run of G nucleotides on the DNA template. In rho-independent termination, when the polymerase encounters a region rich in C-G nucleotides the mRNA folds into a hairpin loop that causes the polymerase to stall.#N#b . Rho-independent termination is controlled by rho protein and the polymerase stalls near the end of the gene at a run of G nucleotides on the DNA template. In rho-dependent termination, when the polymerase encounters a region rich in C-G nucleotides, the mRNA folds into a hairpin loop that causes polymerase to stall.#N#c . Rho-dependent termination is controlled by rho protein and the polymerase begins near the end of the gene at a run of G nucleotides on the DNA template. In rho-independent termination, when the polymerase encounters a region rich in C-G nucleotides, the mRNA creates a hairpin loop that causes polymerase to stall.#N#d. Rho-dependent termination is controlled by rho protein and the polymerase stalls near the end of the gene at a run of G nucleotides on the DNA template. In rho-independent termination, when the polymerase encounters a region rich in A-T nucleotides, the mRNA creates a hairpin loop that causes polymerase to stall.
In prokaryotes the polymerase is composed of four polypeptide subunits, two of which are identical. These subunits, denoted α, α, β, and β ′ comprise the polymerase core enzyme. There is a fifth subunit that is involved in translation initiation. The polymerase comprised of all four subunits is called the holoenzyme.
The polymerase comprised of all four subunits is called the holoenzyme. c. In prokaryotes the polymerase is composed of five polypeptide subunits, two of which are identical. Four of these subunits, denoted α, α, β, and β ′ comprise the polymerase holoenzyme.
What would happen if the 5’ methyl guanosine was not added to an mRNA?#N#a. The transcript would degrade when the mRNA moves out of the nucleus to the cytoplasm.#N#b. The mRNA molecule would stabilize and start the process of translation within the nucleus of the cell.#N#c. The mRNA molecule would move out of the nu cleus and create more copies of the mRNA molecule.#N#d. The mRNA molecule would not be able to add the poly-A tail on its strand at the 5’ end.
Only a fraction of DNA encodes proteins. The noncoding portion of a gene is referred to as the intron. The intron fraction depends upon the gene. Introns are rare in prokaryotic and mitochondrial DNA; in human nuclear DNA, this fraction is about 95%. The intron is transcribed into mRNA, but this noncoding mRNA is edited out before translation of the coding portion, or exon, of a gene. The edited exon segments are then spliced together by a spliceosome, a very large and complex collection of RNAs and proteins.#N#Although introns do not encode proteins, they have functions. In particular, they amplify expression of the exon, although the mechanism is unknown. When introns are very long, which is common among mammalian genes with roles in development, they can significantly extend the time required to complete transcription. Analysis of genes common to different plant and animal species shows many shared intronic positions and base sequences, although in some organisms, such as yeast, many introns have been deleted. Because introns do not encode proteins, mutations can remain silent and accumulate.#N#A. As described above, introns are ancestral remnants that are replicated because they do not disadvantage the organism. Consider the claim that introns are “junk DNA.” Evaluate the claim with supporting evidence.#N#B. Introns may be retained during transcription. Explain how the retention of a transcribed intron between two transcribed exons within a gene could do the following:#N#• block expression of one polypeptide sequence#N#• increase expression of a polypeptide#N#• alter the polypeptide expressed
A pair of allelic disorders may result from mutations in different parts of the gene; be localized (a single base change) or catastrophic (a missing gene); or alter the protein in ways tht affect interactions wit other proteins.
The effect of a mutation is called a "loss-of-function" when the gene's product is reduced or absent, or a "gain-of-function" when the gene's activity changes. Most mutations are recessive and cause a loss-of-function. Gain-of-function mutations tend to be dominant + called "toxic.".
The tiny mutation responsible for sickle cell disease is a substitution of the amino acid valine for the glutamic acid that is normally the sixth amino acid in the beta globin polypeptide chain. At the DNA level, the change was even smaller—a CTC to a CAC, corresponding to RNA codons GAG and GUG.
A mutation is a change in a DNA sequence that is rare in a population and typically affects the phenotype. "Mutate" refers to the process of altering a DNA sequence.
Because the mutation prevents CCR5 from moving to the cell surface from inside the cell, HIV cannot bind. Heterozygotes for this mutation are partially protected against HIV infection. The term mutation refers to genotype—that is, a change at the DNA or chromosome level. The familiar term mutant refers to phenotype.
A mutation is a change in a DNA sequence that is rare in a population and typically affects the phenotype. "Mutate" refers to the process of altering a DNA sequence. Click card to see definition 👆. Tap card to see definition 👆.
Humans have two types of excision repair. Nucleotide excision repair replaces up to 30 nucleotides and removes errors that result from several types of insults, including exposure to chemical carcinogens, UVB in sunlight, and oxidative damage. Thirty different proteins carry out nucleotide excision repair.