Estimate the percentage of time that a constantly developing cell spends in interphase.

/in /by
Virtual Lab 2:           Cellular Processes
A. Bacterial Growth. Observing the growth of the bacteria Streptococcus pneumoniae
These Streptococcus bacteria have been placed on a nutrient rich agar medium and their growth visualized. You can monitor their growth by watching the middle frame and moving through time with the time step buttons.
•   Estimate how long it takes for this population of bacteria to double. Hint- this population doubles multiple times during the duration of this recording.
B. Cellular Reproduction : The Cell Cycle (1 , 2 , 3), Mitosis (1 , 2), Meiosis (1 , 2), and Binary fission (1 , 2).
•  1. Estimate the percentage of time that a constantly developing cell spends in interphase.
•  2. In a random selection of 100 such cells, estimate the number that would be undergoing mitosis at any given time.
•  3. Understand the basic differences between mitosis, meiosis, and binary fission.  Is mitosis
more similar to meiosis or to binary fission? Explain your reasoning.
C. Cellular Metabolism: Cellular Respiration (1 , 2), Photosynthesis (1 , 2), and The Carbon Cycle (1 , 2 , 3)
•  1. In a paragraph or two compare and contrast  photosynthesis and cellular respiration.
•  2. Describe the ecological relationship between photosynthesis and cellular respiration.
•  3. Hypothesize about what might happen if a large number of producers were suddenly removed from the biosphere. Where might carbon accumulate if the ratio of number of producers to consumers was markedly reduced?

Gauge the size of various biological components and organisms.

/in /by

The Virtual labs (below) are online laboratory simulations that enable you to perform experiments and observations in microscopy, microbial growth, inheritance, and genetic analysis from the relative comfort of your computer.
Use the Virtual Lab Report form to record your observations and results from these online experiments. When saving your work, title your report with your last name, first initial ‘_V1’. Thus the title for Charles Darwin’s report is DarwinC_V1. Use the ‘Save As’ option to save the file as Word 97 .doc file. Submit the report in the Dropbox before 11:00 PM PST on the second Saturday of class.
     Virtual Lab Report Part I         Due: Second Saturday of the course

Virtual Lab 1:            Virtual Microscopy
A. Gauge the size of various biological components and organisms. The Virtual Microscope can be used to make these observations. Estimate the size (length and width in microns) of
•  1. An E. Coli cell
•  2. A mitochondrion.
•  3. A Red blood cell
•  4. A virus.
•  5. A water molecule
B. Observe the various Cell types and learn to distinguish between Bacterial cells, Plant cells (1, 2), and Animal cells (1, 2, 3)
•  1. Observe and describe three differences between prokaryotic and eukaryotic cells.
•  2. Observe and describe three differences and three similarities between plant and animal cells.
C. Form a hypothesis
•  1. Hypothesize about how you might be able to sort a mixed population of cells into prokaryotes and
eukaryotes. Try to be practical, build on your understanding of the differences between the two cell classes.
•  2. Hypothesize about a means to separate out plant cells from a mixed population of eukaryotic cells.
Supplemental:
Cell structures and functions
Virtual Optical Microscope.
Virtual Scanning Electron Microscope (SEM).
Scanning Electron Microscope (SEM) images.

 What is the purpose genetic engineering of crop plants and domestic animals?

/in /by
Biology and Technology in the Real World
Instructions  
Written Assignment: Biology and Technology in the Real World
Addresses course outcomes 1-4:

  • recognize and explain how the scientific method is used to solve problems
  • make observations and discriminate between scientific and pseudoscientific explanations
  • weigh evidence and make decisions based on strengths and limitations of scientific knowledge and the scientific
  •  method
  • use knowledge of biological principles, the scientific method, and appropriate technologies to ask relevant
  • questions, develop hypotheses, design and conduct experiments, interpret results, and draw conclusions

1. Select one of the topics listed below.
2. Find at least two information sources related to the topic. You can find assistance with searching for articles at the
athttp://libguides.umuc.edu/science.
3. Write a 750-1500 word paper, excluding references and title page. You must read the information sources that you
find and summarize the information in your own words, addressing each of the questions and expectations for your
chosen topic. Extensive quotes from the article are discouraged. Use APA style for citing references,
seehttp://www.umuc.edu/library/guides/apa.html.
4. Post your assignment to your Assignments folder by the due date listed in the course schedule.
Topics (select one)
a)     Genetically modified organisms (GMOs). What is the purpose genetic engineering of crop plants and domestic
animals? Briefly explain how GMOs are created. What foods in your supermarket contain GMOs? Are foods that
contain GMOs safe for human consumption? What types of regulations exist for these foods? Clearly explain your
reasoning for each answer. The following website from FDA regarding GMO regulation may be helpful:http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm352067.htm
b)    Stem cells. Your friend had a spinal cord injury after a bad car accident. The medical team has decided that he is a
good candidate for a clinical trial using stem cell therapy. Your friend has not had a biology course since high
school, so you decide to write him a letter sharing your knowledge of stem cells. Include in your letter a description of
the biology of stem cells and how these cells are unique from other cells. Contrast the different types of stem cells,
including pros and cons of each.
Explain how stems cells are can be used to treat diseases and injury, with special focus on spinal cord injuries.
Conclude with your own opinion. The following website from NIH regarding stem cell research will be very helpful:
http://stemcells.nih.gov/index.asp.
c)     Fracking (hydraulic fracturing) and tar sands (oil sands).  With society’s dependence on nonrenewable fossil
fuels, the oil & gas industry is turning to the use of hydraulic fracturing and tar (oil) sands to extract natural gas and
oil respectively.  A friend asks you “What’s all this controversy in the news about fracking and tar sands?”  Briefly
explain to your friend how hydraulic fracturing and tar (oil) sands are used to obtain these fossil fuels. Then, in more
detail, describe the environmental problems that may result from these processes and why they are controversial.
Issues that may be addressed involves, but are not limited to, water, air and soil pollution, effects on human health,
effects on other species and natural ecosystems. Finally, give your opinions on possible solutions to these
environmental problems, with your reasoning backed by the references that you studied. The following websites
from EPA may be helpful: http://www2.epa.gov/hydraulicfracturing

How much time is required for the potassium ions in the liposome to reach equilibrium with their environment?

/in /by
Biology homework help
Course Number: 211G A20 Course Name: Online – Cellular and Organismal Biology Instructor: Catherine Hartkorn Individual/Partner Project – Biology Math Problems Assignment Write out… Course Number: 211G A20 Course Name: Online – Cellular and Organismal Biology Instructor: Catherine Hartkorn Individual/Partner Project – Biology Math Problems Assignment Write out your calculations and explanations for ALL problems. To solve the problems in this problem set, you will need to review (or look up, if you cannot remember) some geometry formulas. Problem Set 2 – Problems on Cell Structures and Membranes (3 problems): 3. Lysosomes are little sacs of acid in a cell. Their pH is about 5, and an electron micrograph suggests they have a diameter of 0.5 μm. The increased hydrogen ion concentration inside lysosomes is due to the pumping of hydrogen ions across the lysosomal membrane from the surrounding cytosol, which has a pH of 7.2. a. Assuming that a lysosome has the shape of a sphere and that there is no buffering capacity inside the lysosome, how many hydrogen ions were moved to the inside of the lysosome to lead to an internal pH of 5? (hint: first determine the volume of a lysosome in liters, then determine [H+] in moles/L in a lysosome at each pH (5 and 7.2), then determine the number of moles of hydrogen ions at each pH, and finally determine and compare the number of hydrogen ions at each pH). 4. Liposomes are laboratory-prepared artificial membranes. Liposomes can be made in a variety of sizes and can be made so that they have transmembrane proteins, which form membrane. Contents of the liposomes can also be known. For example, let’s say that one lab makes liposomes that are spheres with the diameter of 4 μm and that each liposome has an average of ten protein pores. Each liposome has an internal potassium ion concentration of 100 mM. Each protein pore transports 3x 10^6 potassium ions per second. The pores stay open an average of 0.3 second and stay closed an average of 2 seconds; so, each pore opening and closing cycle takes about 2.3 seconds. a. Assuming that a liposome has the shape of a sphere, how many potassium ions are in a liposome initially? (hint: the method here is similar to what you used to solve problem 3 above, except find the volume of a liposome in μm^3 and the [K+] in mol/μm^3) b. How much time is required for the potassium ions in the liposome to reach equilibrium with their environment? Assume that this environment is relatively large and potassium-free. (hint: before calculating the total time it would take to reach this equilibrium, think about how many potassium ions would need to leak out of the liposome in order to reach this equilibrium – all of them, half of them, none of them, why?) 5. Glycophorin is a single-pass transmembrane protein in red blood cells (RBCs). The protein component of glycophorin is 131 amino acids long and binds carbohydrates on the outside (noncytoplasmic side) of glycophorin. Then, approximately 100 modified sugar residues are attached near the end of each glycophorin; these account for about 60% of this macromolecule’s mass. The average molecular weight of an amino acid is 130 daltons. a. What is the average molecular weight (in daltons) of each modified sugar residue on the glycophorin? b. An RBC contains an average of 6 x 10 ^5 glycophorin molecules. How many modified sugar residues are found attached to glycophorins in one RBC? c. How many grams does the protein component of glycophorin weigh in one RBC?