6. a. If the oligopeptide AFVRWGTHLESKLVMSLDIHLRF were cleaved completely by reaction with trypsin and V8 protease and the products subjected to ESI TOF-MS in positive ion mode with the peptides in a pH 2 solution, which product will reach the detector last? Explain why.

2. If the Lys on the oligopeptide were to be acetylated on its side chain, would the last peptide to reach the detector be changed? Explain.
3. To determine the M_r of a purified protein, you subject it to ESI TOF-MS in positive ion mode with the protein in a pH 2 solution. The spectrum shows a series of peaks with the two most prominent neighboring peaks having m/z ratios of 648.78 and 659.52. What is the uncharged mass of the protein (i.e., M_r at its pI) in the 648.78 peak?
4. Is the charge on the protein in part c consistent with the protein having a typical basic amino acid composition? Justify your conclusion mathematically.

1. What is a peptide bond? 2. How does the primary structure of proteins differ from the secondary structure? A. Peptide Bonds A.1 Structure of glycylserine Structure of serylglycine A.2 Hydrolysis of serylglycine

Q.1 Why are heat and alcohol used to disinfect medical equipment?

Q.2 Why is milk given to someone who accidentally ingests a heavy metal ion such as silver or mercury?

Q.5 After working with HNO3, a student noticed that she had a yellow spot on her hand. What might be the reason?

Q.6 Which samples above give a negative biuret test? Why?

Q.7 What functional group gives a positive test in the xanthoproteic test?

Q.8 What tests could you use to determine whether an unlabeled test tube contained an amino acid or a protein?

You have discovered a new transmembrane protein that resides in the ER. The molecular weight of the protein is approximately 100 Kd and it contains a hydrophobic transmembrane domain in middle of the protein amino acid sequence. You want to determine whether the protein is a Type I or Type II transmembrane protein. For the experiment, you are given the following reagents: cDNA construct for the protein, a cell line, a centrifuge, SDS-page apparatus, reagents needed for Western blot analysis and an antibody made against the N-terminus of the protein. Basic biochemicals and enzymes routinely used in cell biology research labs are also available to you. Briefly outline your experimental strategy for determining the topology of the protein and show expected Western blot analysis results if the protein is 1) Type I transmembrane protein or 2) Type II transmembrane protein.

10.Which base pairing is incorrect for DNA replication (not protein synthesis)

a. A-T

B. T-A

C. G-C

D. U-T

12.Cancer results from unchecked

a. Mitosis

b. Meiosis

c. Homeostasis

d. Complementarity

22. Which of the following is true about aerobic cellular respiration?

a. it occurs in both plant and animal cells

b. It is a catabolic reaction

c. Sugar ( in the presence of oxygen) is broken down into carbon dioxide and water, releasing energy.

d. all of the above is true.

31. Which of the follwoing is true about the amino acid code?

a. the code is nearly universal

b. the code is redundant

c. the code had no redundancy

d. both a and b

32. what is the function of an operon?

a. promotes the expression of a gene

b. codes for the production of proteins

c. allows binding of suppressor proteins

d. none of the above

A) Which of these groups is known from fossils in both Europe and Africa from 200,000 years ago?

• A. Homo heidelbergensis
• B. Neandertals
• C. Anatomically modern Homo sapiens
• D. Denisovans

B) What did the discovery of Neanderthal DNA in modern human genomes tell us about gene flow as Homo sapiens emerged from Africa?

• A. All of the human variation that exists today was derived from the variation that existed in the population of Homo sapiens that first emerged in Africa; there is no evidence of interbreeding with other hominin populations.
• B. Very little human variation is derived from what was present in the population of Homo sapiens that first emerged in Africa; a significant amount of variation was introduced after interbreeding with Neanderthals and Denisovans.
• C. Human variation is largely derived from what was present in the population of Homo sapiens that first emerged in Africa, but a limited amount of variation has been passed from Neanderthals and Denisovans through interbreeding after Homo sapiens emerged from Africa.
• D. Although DNA extraction techniques continue to improve, there are not enough data to provide conclusive evidence about whether modern humans interbred with Neanderthals.

C) The LCT allele for persistence of lactase until adulthood is today found at high frequency (40-100%) in various populations of Europe, where dairy farming has been practiced for thousands of years. Which of the following is our current understanding of the origins of the allele in Europe.

• A. The allele originated in Europe after hunter-gatherers began keeping dairy cattle and the mutation went to high frequencies quickly under strong selection.
• B. The allele spread from the Near East via farmers who also introduced crops, animals and agricultural technology to Europe around 7,500 years ago.
• C. The allele was present at low frequency in cattle and sheep herding nomads that spread to Europe from the Russian steppe 4,500 years ago.
• D. The allele spread to Europeans via introgression from Neandertals.

D) Which of the following are real limitations of direct-to-consumer percentage ancestry tests? Select all that apply.

Learning Task 12-01

The Enzyme Lactase Experiment Design

Which question will your experiment investigate? (select one and delete the others)

How does temperature affect how lactase drops work to break down lactose into glucose and galactose?

How does pH affect how lactase drops work to break down lactose into glucose and galactose?

How does agitation (movement) affect how lactase drops work to break down lactose into glucose and galactose?

What variable will you change in this experiment? This is also called the Independent variable.

How will you change it?

What variable will you measure in this experiment to determine the effect of the variable you changed? This is also called the Dependent variable.

How will you measure it?

What variables will you keep the same in this experiment?

Check off the items in this list that you would use for this experiment. You may add any items you feel you would need.

Describe what you would do in your experiment. For each step, explain why the step is important. Add more steps if required.

If you actually conducted this experiment, what safety issues would you need to identify?

If you actually conducted this experiment, what appropriate precautions would you take to ensure that you performed the experiment safely?

If you actually conducted this experiment, what results would you expect to see?

Why would you expect these results?

Read the following article to assess if this claim scientific by answering the questions that follow:

The term lunar effect refers to correlations between specific stages of the roughly 29.5-day lunar cycle and behavior in humans or other living things. In some cases these rhythms may depend on external cues, such as a greater or smaller amount of moonlight due to the moon's phases. A considerable number of studies have examined the effect on humans. By the late 1980s, there were at least 40 published studies on the purported lunar-lunacy connection,and at least 20 published studies on the purported lunar-birthrate connection. However, several extensive literature reviews and meta-analyses found no correlation between the lunar cycle and human biology or behavior.

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Other studies found evidence that those with mental disorders i.e. Schizophrenia generally exhibit 1.8% of increased violent or aggressive episodes during the full Moon, but a more recent study found no such correlation to that of non-schizophrenic human beings^. An analysis of mental-health data found a significant effect of Moon phases, but only on schizophrenic patients.

A recent study of 33 volunteers that did not account for age and sex found a statistically significant connection between sleep quantity and quality and lunar phases, even though the subjects could not see the moon or its light.  A July 2013 study carried out at the University of Basel in Switzerland suggests a correlation between the full Moon and human sleep quality.^[5] Professor Cajochen and colleagues presented evidence that a lunar rhythm can modulate sleep structure in humans when measured under the highly controlled conditions of a circadian laboratory study protocol without time cues. Studying 33 volunteer subjects, the researchers found that subjective and objective measures of sleep varied according to lunar phase and thus may reflect human circalunar rhythmicity. Stringently controlled laboratory conditions, in a cross-sectional setting, were employed to exclude confounding effects such as increased light at night or the potential bias in perception. Measures of lunar influence on sleep structure, electroencephalographic activity during non-rapid eye movement sleep (NREM), and secretion of the hormones melatonin and cortisol, were retrospectively analyzed.   Cajochen said: "The lunar cycle seems to influence human sleep, even when one does not 'see' the Moon and is not aware of the actual Moon phase."

However, there are suggestions that the 2013 Cajochen study is faulty because of a relatively small (n=33) sample size and inappropriate controls for age and sex. A 2014 study with larger sample sizes (n1=366, n2=29, n3=870) and better experimental controls found no effect of the lunar phase on sleep quality metrics. A 2015 study of 795 children found a 3 minute increase in sleep duration near the full moon, but a 2016 study of 5,812 children found a 5 minute decrease in sleep duration near the full moon. No other modification in activity behaviors were reported, and the lead scientist concluded: "Our study provides compelling evidence that the moon does not seem to influence people's behavior."

1. What are the scientific bases for the claim that there is a lunar effect on human behavior?