Of 31 children born of father-daughter matings, 6 died in infancy, 12 were abnormal and died in childhood, and 13 were normal. From this information calculate roughly how many recessive lethal genes we have, on average, in the human genome. (Hint: if the answer were 1, then the daughter would stand a 50% chance of carrying the lethal allele, and the probability of the union’s producing a lethal combination would be 1/2 * 1/4 = 1/8. So, 1 is not the answer.) Discuss the possibility of undetected fatalities in utero in such matings. How would they affect your result?
In: Biology
Explain how a pathogen can escape your innate immune defenses.
In: Biology
Approximately 25% of human tumors are found to have activating mutations in Ras. How do these mutations contribute to the tumor development?
In: Biology
(30) The textbook discusses human blood typing (ABO) from both phenotypic and genotypic perspectives. If a particular red blood cell exhibits both the cell surface antigens designated glycoproteins A and B, we designated the blood type AB. This type of genetics is an example of multiple alleles and which of the following types of dominance?
(A) complete dominance (B) co-dominance
(C) partial dominance (D) non-dominance
In: Biology
Two different genes controlling pod morphology in peas are found on chromosome 5. The narrow pod trait is recessive to wide pods and yellow pods is recessive to green pods. A heterozygous plant is generated by mating a narrow green pod plant with a wide yellow pod plant. This plant was testcrossed and the following progeny were obtained. What is the linkage relationship between the two genes?
144 Narrow green pods , 150 wide yellow pods , 110 narrow yellow pods , 90 wide green pods
In: Biology
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a. |
Are found on the plasma membrane. |
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b. |
Are ion channels. |
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c. |
Dimerize when binding to their signaling molecule. |
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d. |
Are transmembrane proteins. |
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e. |
Contain a protein kinase domain. |
2. During protein synthesis, a protein is made in which direction?
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a. |
From the 2' end to the 3' end. |
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b. |
From the 3' end to the 2' end. |
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c. |
From the 2' end to the 3' end and from the 3' end to the 5' end. |
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d. |
From the amino-terminal end to the carboxyl-terminal end. |
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e. |
From the carboxyl-terminal end to the amino-terminal end |
3. What type of molecule is ATCAGCTAG?
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Protein. |
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Phospholipid. |
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DNA. |
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RNA. |
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Glucose. |
4. In the lytic cycle:
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a. |
A bacteriophage interacts with an episome and stimulates transcription of the bacterial chromosome. |
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b. |
A bacteriophage replicates to very high numbers within a bacterial cell and eventually the bacterial cell bursts to release the new viruses. |
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c. |
A bacteriophage binds to the lac repressor and stimulates translation of Rubisco RNA. |
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d. |
A bacteriophage genome is stably integrated into the bacterial chromosome. |
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e. |
A bacteriophage stimulates the transcription of an R factor. |
5. Which of the following organisms would be expected to have the largest genome size?
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a. |
Bacteriophage T4. |
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b. |
Escherichia coli. |
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c. |
Yeast (Saccharomyces cerevisiae). |
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d. |
Homo sapiens (humans). |
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e. |
Human immunodeficiency virus (HIV). |
6. For a protein to be inserted into the endoplasmic reticulum membrane:
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a. |
The protein must have a promoter. |
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b. |
The protein must have a telomere. |
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c. |
The protein must have a centromere. |
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d. |
The protein must have a signal sequence. |
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e. |
The protein must be in a complex with DNA. |
In: Biology
Your human body has two chemical messenger systems: Neurotransmitters and Hormones. 1) Where does each system primarily operate? 2) Which system is slower? 3) Briefly describe how the HPA axis uses three main structures to cause cortisol to be released into the bloodstream. 4) How does the HPA axis prevent itself from constantly releasing cortisol into the bloodstream once the threatening stimulus has gone away?
In: Biology
Explain the mechanism by which the signaling by the Epinephrine receptor is amplified inside the cell. And also explain the merit of signal amplification.
In: Biology
2. At what point do the carbon atoms of each of the following amino acids enter metabolic pathways for the production of energy? State citric acid cycle, etc.
a. valine b. proline c. glycine
In: Biology
8. Explain how the lacZ gene will be expressed when bacteria with loss-of-function mutations in the lacI gene are in an environment free of both lactose and glucose.
In: Biology
Some bacteria produce multiple toxins that interfere with the host’s immune response. For example, one bacterial toxin is a protease that cleaves the proteins that form tight junctions between skin cells. The result is severe, widespread blistering (patches of skin sort of peel away from the body). (a) Explain how this toxin helps the pathogen. (b) What branch of the immune system can best defend against this toxin?
In: Biology
Explain the mechanism by which a missense mutation in the RAS gene that impairs the GTPase activity of the RAS protein promotes cancer cell division.
In: Biology
. Explain the mechanism by which the signaling by the Epinephrine receptor is amplified inside the cell. And also explain the merit of signal amplification.
In: Biology
Hypothesis 1: Mercury in thimerosal caused neurological damage
in children, and is at least partly responsible for
the increase in autism diagnoses.
Hypothesis 2: The rate of autism incidence is not increasing, only
the rate of autism diagnoses, as greater awareness
of the syndrome and increased screening of children yields more
positive diagnoses of autism.
based on both hypothesis..
Do both hypotheses make testable predictions? How could you test them? please explain
In: Biology
In: Biology