Activity 2: Transcription

Imagine that you’re having a house built. The architect draws up a set of blueprints for the builder. The builder, in turn, has to hire several subcontractors for the electrical, plumbing, and heating systems. The builder doesn’t wish to give up the original set of blueprints, so copies are made for each of the subcontractors.

This same principle applies to a cell. The nucleus contains the master set of blueprints, the DNA. DNA molecules are needed to direct the activities that occur in the cytoplasm of each cell.

When other organelles need to manufacture materials for the cell, copies of the master blueprint are made, so that the originals are not damaged or lost. This process is referred to as transcription. The copies made by transcription will be in the form of another molecule called messenger RNA (mRNA)

There are several differences between DNA and mRNA:

In this activity you’ll transcribe a DNA code into mRNA. The DNA sequence in this activit represents a gene located on one of the chromosomes in the nucleus of a cell that codes for a specific protein.

1. Since thymine isn’t found in mRNA, the base pairing rule you learned in the previous activity must be altered. Complete Table 9-2 by entering the appropriate bases.

Table 9 – 2 mRNA Base pairing

2. Looking at Figure 9 – 2, you can see that column one contains the DNA sequence found along one side of a double helix.

Fill in the appropriate mRNA sequence in the second column.

3. The mRNA code is composed of a sequence of three bases along the mDNA molecule. The three bases are referred to as a codon.

ATG is the first triplet on the DNA sequence. What is the corresponding codon?

4. How many codons does your mRNA strand contain?
5. What is the base sequence of the fourth codon of your mRNA?

FIGURE 9-2

Activity 3: Translation and protein synthesis

Having copied the DNA into mRNA leaves the nucleus of the cell and travels to a ribosome.

Reminder: Ribosomes are the sites of protein synthesis within a cell

Proteins are composed of chains of amino acids. A chain of amino acids is also referred to as a polypeptide chain because the amino acids are held together with a type of covalent bond called a peptide bond.

Amino acids are brought to the ribosome by another type of RNA called transfer RNA (tRNA). The codons in the mRNA determine the sequence and number of amino acids being bonded into the corresponding protein.

1. Refer to the mRNA codons in Table 9-3 to determine the amino acid sequence for your protein.

To do this, just match each codon in your mRNA sequence to the corresponding amino acid as listed in the table.

Fill in column three of Figure 9-2 with the correct amino acids.

2. How many amino acids does your protein contain?
3. What is the sixth amino acid in the polypeptide chain?
4. If the sixth triple read GAA instead of GGA, would the sequence of amino acids change? Explain your answer.
5. If the sixth triple read GGC instead of GGA, would the sequence of amino acids change? Explain your answer.
6. What is the name of the bonds that attach the amino acids together within the polypeptide chain?

Animals evolved certain traits in order to adapt to their environments. These traits inform their life histories such as where the species lives, what it eats, and how it behaves. Explain at least two anatomical differences between amphibians and reptiles which explain their very different relationships to water. Explain two anatomical features that would shed light on the life history of a bird species, such as what it eats, where it lives, or any other feature. Explain the anatomical feature that would most help a scientist trying to figure out what kind of food a mammal species eats.

1. The alpine sky pilot, Polemonium viscosum is a common flowering plant in the Rocky Mountains. At high elevations, P. viscosum is pollinated mainly by B. kirbyellus bumblebees; At lower elevations, it is pollinated mainly by flies. A biologist observed that alpine sky pilot populations growing at higher elevations had significantly larger flower corollas than those growing at lower elevations.

a) Explain why flower size would be likely to affect the fitness of sky pilots at different elevations.

b) Explain why, based on fitness differences, average flower size has become different at high and low elevations.

2. A biologist claims that although the two sky pilot populations have different flower sizes, they are the same biological species.

a) How would the biologist test this hypothesis?

b) What experimental outcome would support the hypothesis that the two populations are the same biological species?

What is the significance that primates generally give birth to one offspring at a time and the elongations of gestation and infant dependency? What does this mean about the degree of learning found among prosimians, monkeys and apes.

• How does the route of administration for tropisetron relate to its activity and effectiveness? Would you have expected tropisetron to present with this activity based on its structure and physicochemical properties? Why or why not?

A number of other related drugs with a similar indication to tropisetron are not being considered for use in Alzheimer’s disease. What distinguishes tropisetron from other drugs? Consider the paper and its specific findings.

Biology review Sheet - NEED ANSWERS ASAP - the last person did this very poorly

1. Identify and differentiate between the asexual spores and sporangia produced by zygomycetes and the conidia and conidiophores produced by ascomycetes.

2. Describe mycorrhizae and lichens and explain the role of each organism involved in each of these mutualistic relationships. If presented with a lichen specimen, you should be able to identify it as such.

3. Ste why Bryophytes (mosses) and Pteridophytes (Ferns) are restricted to habitats that are moist.

4. State why Bryophytes exhibit low, sprawling growth.

5. Differentiate between xylem and phloem.

6. Define Heterospory and distinguish between microspores and megaspores (i.e. with respect to what they develop into). State which plant groups are heterosporous.

7. List for differences between seeds and spores.

8. Describe pollen (i.e. what is pollen?) and explain why pollen provides and advantage to plants that produce it.

9. Describe a seed (i.e. what is a seed?) state which generation (gametophyte or sporophyte) develops from a seed, and state the advantage of producing seeds.

10. Describe a flower; label the parts of a flower; identify the male and female reproductive organs; the site of pollen production; site of egg production; and site of fertilization; and state the purpose of flowers.

11. Define fruit and explain how fruits are advantageous to flowering plants.

12. State which structures of the flower develop into the seed and fruit respectively.

13. Differentiate between simple, aggregate, accessory, and multiple fruits, with examples.

14. Compare and contrast the life cycles of bryophytes, pteridophytes, gymnosperms, and angiosperms (some of this included in the list for objective 6 above).

part 2

1. Describe at least 5 characteristics that green algae and land plants have in common.
2. List and briefly describe at least 5 challenges faced by plants in “making the move to land”.
3. List at least 5 adaptations (shared derived characteristics) of land plants and briefly explain how these4 features are adaptive for life on land.
4. Diagram the generalized alternation of generations, the reproductive cells produced (spores, gametes, and zygote) and where mitosis, meiosis and fertilization take place.
5. Indicate which stages/structures in the alternation of generations life cycle are haploid and which are diploid, and which are multicellular and which are unicellular.
6. Compare/contrast phylum Bryophyta, Pteridophyta, Pinophyta, Cupressophyta, and Anthophyta with regards to:

• The presence of a waxy cuticle, sporangia and gametangia, and embryo retention.
• The presence of stomata
• The presence of vascular tissue
• The presence of true roots and leaves
• The dominance, size and independence of the sporophyte and gametophyte stages
• How fertilization is accomplished (i.e. do flagellated sperm swim to the egg or is the male gametophyte transported to the female via wind and/or animal dispersed pollen grains?).
• The reproductive structures that are being dispersed
• If the female gametophyte is contained within and ovule, and if so, the ovule is within an ovary.
• Whether seeds, flowers and/or fruit are produced
• … and be able to state/identify/describe any other distinguishing features of these phyla that are noted in you lab manual 9e.g., rhizoids, sori, cones, the sporophytes vs. gametophyte generation…etc).

part 3

1. List the general characteristic of fungi that distinguish them from members of other multicellular kingdoms (i.e. Plants and Animals).
2. State at least two characteristics of fungi that support the hypothesis that they are more closely related to animals than to plants (i.e. what are some features found in fungi and animals, but not in plants?).
3. Explain how fungi acquire their nutrients.
4. Describe the basic body plan of a multicellular fungus.
5. State what a yeast is.
6. Differentiate between coenocytic and septate fungi.
7. Draw/fill-in/answer questions related to a diagram illustrating the basic (generalized) lifecycle of a fungus, including asexual and sexual reproduction. Identify the haploid, diploid, and heterokaryotic stages, and define plasmogamy and karyogamy.
8. State the function of a fungal fruiting body
9. Explain the significance of cyanobacteria to the evolution of life on Earth and the important roles cyanobacteria play in ecosystems.
10. Identify specimens of any of the cyanobacteria colony, and state the significance (role) of these cells.
11. Explain why it s that people who cannot tolerate milk can often eat yogurt.
12. Given the results of the gram stain, be able to identify which bacteria are Gram positive and which are gram negative
13. Define zone of inhibition.
14. Given a plate (or and image of a plate) that has been incubated with bacteria and antibiotic discs, identify which antibiotic(s) the bacterium was sensitive to, which antibiotic(s) the bacterium was resistant to, and justify your answer by explaining how/why the zones of inhibition form and what a larger zone means. → Hint: Your answer should refer to the concentration antibiotic as it diffuses in to the agar.
15. Explain how pathogenic bacteria may acquire antibiotic resistance, how antibiotic resistance can quickly spread through a bacterial population, and how misuse of antibiotics an promote prevalence of resistant strains → Hint: Your answer should refer to mutations , lateral/horizontal gene transfer, rapid reduction in bacteria, and natural selection (i.e. change environment with addition of antibiotic → resistant strains favored)

16. Briefly explain why antibiotics are effective at killing bacterial cells, but do not seem to impact human sells. → Hint: This is in your assignment.

part 4

1. State several characteristics of Archaea that distinguish this group from Bacteria.
2. Distinguish between halophile, thermophiles, and methanogens.
3. List the major characteristics that define domain Bacteria
4. Differentiate between cocci, bacilli, and spirilli.
5. Define “endospores” and explain how endospores have contributed to the success of some bacteria.
6. Differentiate between the following modes of nutrition: photoautotroph, chemoautotroph, photoheterotroph and chemoheterotroph.
7. Differentiate between obligate aerobe, obligate anaerobes, and facultative anaerobes.
8. Understand/explain sterile technique. Both when pouring plates and spreading bacteria on plates.
9. Distinguish between the structure of Gram positive and Gram negative bacteria, and clearly explain how these differences allow the Gram staining procedure to differentiate between these groups (this will require both explaining how the Gram staining procedure is carried out and how differences in morphology of these two groups of bacteria result in different end colors).

part 5

1. Define “taxonomy”.
2. Define “binomial nomenclature” and know how to properly write an organism’s scientific name.
3. List the major taxonomic categories or the current hierarchical classification system, from the most to least inclusive.
4. Describe Linnaeus’ original two kingdom classification and name two shortcomings of this scheme.
5. List three Domains
6. State the guidelines/rules for properly building a dichotomous key and/or identify errors in an example a dichotomous key and/or build a dichotomous key using a given set of specimens

The general structure of the replication fork and the enzymes and steps involved in resolving Okazaki fragments.

2.) Consider the following RNA sequence, which represents the beginning of an open reading frame: 5’-AUGGGACUAGAUACC-3’. Examine each of the sequences below, describe the change to the sequence, and state whether it represents a silent, missense, nonsense, or frameshift mutation. If frameshift, be sure to include the consequences of the frameshift (nonsense or massive missense). Use the codon table. a) 5’-AUGGGUCUAGAUACC-3’ b) 5’-AUGCGACUAGAUACC-3’ c) 5’-AUGGGACUAGUUACC-3’ d) 5’AUGGGACUAAGAUACC-3’ 3. Using a couple of sentences each, describe the function of each of the following in regulating eukaryotic gene expression: a) promoter b) enhancer c) histone acetyltransferase d) 5-methylcytosine

On the planet Proboscide, there are elephants that are the size of flies. They genomic makeup is also very similar to the genomic make up of earth drosophila. There are two genes of interest for the elephants. They are PNT, and WGT.

The PNT gene produces two phenotypes, those elephants that like to eat peanuts and wild types that do not.

The WGT gene produces a wild-type phenotype of elephants near mean-weight, and a mutant phenotype where the weights are extreme (very heavy). Both genes have two alleles at their loci.

The mode of inheritance for the WGT gene is autosomal dominant, homozygous lethal. The mode of inheritance for the PNT gene is autosomal recessive. The two genes are unlinked.

In a cross between a male elephant with both extreme weight and that likes peanuts, and female elephant with wild-type phenotypes for both loci (true breeding at each locus)offspring are produced. Among these offspring, two elephants, both with extreme weight and wild-type PNT phenotypes (don't like peanuts) are crossed. In an F₂ offspring pool of approximately 1000 elephants, the most likely pairs of phenotype counts are:

A. (Phenotype 01, Phenotype 02) Count
(WGT, PNT) 500
(WGT, +) 500
(+, PNT) 0
(+, +) 0

Here, + is the wild-type phenotype at for the repsective gene.

B. (Phenotype 01, Phenotype 02) Count
(WGT, PNT) 570
(WGT, +) 180
(+, PNT) 187
(+, +) 62

Here, + is the wild-type phenotype at for the respective gene.

C. (Phenotype 01, Phenotype 02) Count
(WGT, PNT) 333
(WGT, +) 334
(+, PNT) 167
(+, +) 162

Here, + is the wild-type phenotype at for the repsective gene.

D. (Phenotype 01, Phenotype 02) Count
(WGT, PNT) 0
(WGT, +) 681
(+, PNT) 0
(+, +) 319

Here, + is the wild-type phenotype at for the repsective gene.

E. (Phenotype 01, Phenotype 02) Count
(WGT, PNT) 252
(WGT, +) 252
(+, PNT) 240
(+, +) 261

Here, + is the wild-type phenotype at for the repsective gene.

Please answer in detail.(2 pages)
At the core of a fluorescence microscope is the dichroic mirror. What function does the dichroic mirror perform?