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A teratoma is a tumor composed of several different types of tissue that can include muscle, teeth, hair, or bone. Teratomas develop from germ cells, a type of cell that gives rise to gametes. Because germ cells are not differentiated into specific cell types (as are e.g. muscle cells, skin cells, fat cells, etc.), teratomas can develop exhibiting numerous different cell types, giving them their name teratoma, Greek for “monstrous tumor”. Teratomas may be benign or cancerous. As a result of mistakes in processes of cell division, they are generally diploid, and sometimes polyploid. Consider a cell of a teratoma and a healthy human epithelial (skin) cell. Now consider the DNA and the three types of RNA (mRNA, tRNA, and rRNA) found in both. For each of these (DNA, mRNA, tRNA, and rRNA), compare what you would expect to find in both a teratoma and a healthy cell. Would they be the same, or different, or both? Please explain briefly but clearly for each of these four nucleic acids and provide examples or reasons. 1) DNA 2) mRNA 3) tRNA 4) rRNA Photo credits: https://emedicine.medscape.com/article/281850-overview (left) and Ed Uthman, MD. http://web2.airmail.net/uthman/specimens/index.html (right)

In E. coli, the lac operon should be fully expressed (turned on) ______.

During which part of the cell cycle is DNA polymerase most active?

You cross two plants that have pink flowers. The F1 offspring include mostly plants with pink flowers, some plants with red flowers and some plants with white flowers. Your goal is to have as many pink-flowered plants in the F2 generation as possible. Which F1 plants would you cross to achieve this goal?

Which of the following processes produces the most ATP?

Optional extra credit (2 points)! The SARS-CoV-2 virus responsible for the current COVID-19 pandemic gains entry to epithelial cells especially of the respiratory and oral passageways by binding to angiotensin-converting enzyme 2 (ACE2) found on their surface. The structure of ACE2 is shown below. 1) Consider the ribbons forming coils. What are these particular structures called? 2) What level of protein structure (i.e., primary, secondary, tertiary, or quaternary) are these structures considered, and what type of bonds are primarily responsible for the formation of these structures? Photo credit: Emw – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8761587

When producing unfertilized eggs, female fruit flies deposit mRNA coding for the Bicoid protein at the anterior (head and upper body) side of the egg. Following fertilization, a concentration gradient of Bicoid develops that ranges from high concentration of the protein at the anterior end to a low concentration at the posterior (abdomen and rear end) end. Where Bicoid is present, anterior structures form; in its absence, posterior structures form. Bicoid therefore plays a critical role in the development of structures in the fruit fly. Following fertilization, how is Bicoid produced?

This question has 2 parts You obtain a sample of double-stranded DNA and transcribe mRNA from this DNA.  Then, you analyze the base composition (percentage of each base found in each strand) for each of the two DNA strands and the one mRNA strand. Numbers in the table below indicate the percentage of each base in the strand.  (Note: results may differ from the true value by about 1%; that is the best estimate that the machine you used can make.)  Question a)  Which of these strands must be the mRNA? [A]  b) Which one is the template strand (from which the mRNA was transcribed)? [B]

During which part of the cell cycle is DNA polymerase most active?

A molecule binds to a receptor on the surface of a cell membrane. A short time later the cell responds by expressing genes and synthesizing proteins. What initial process did that binding event first initiate?