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The following Critical Thinking questions are meant to provide deeper understanding of biology topics after students have watched this week's Panopto lectures. Attempting to answers these before lectures have been watched, may compromise your understanding and participation in this course.

In the future, I will be subdividing the class into smaller online groups to answer these questions so it may be less intimidating for the "shy" person, but for this first one I wanted to do it as a class.

How do your get graded? Well, you are NOT graded on whether you answer the questions correctly! You are graded on how well you use critical thought from our lecture and chapter readings to synthesize answers. Your posts should NOT be long, multi-paragraph essays but rather concise statements that are well thought out. They can even be in the form of a question or inquiry such as "...I know that only proteins have disulfide bridges so if a stain binds to these groups then it should change color, however I'm not sure how that relates to the question...". Help each other out if some people are struggling to understand the question or are having difficulty seeing a point of view. Some questions may not have a correct answer! I will reveal the answers or possible answers after the due date.

For each question below post one critical thinking post and one critical thinking reply to another student before the due date (that's a total of 8 posts all together). Note that your posts doesn't have to answer the question completely...partial answers to a question are fine!

Macromolecules

1. Trans-fatty acids are a type of unsaturated fat. Most trans-fats consumed today are industrially created as a side effect of partial hydrogenation of plant oils (Crisco). In trans-fat molecules, the hydrogens on the doubly bonded carbon atoms (characteristic of all unsaturated fats) are straighter, rather than kinked, in shape. Why do you think trans-fats are considered unhealthy as compared to other unsaturated fats? Can you explain your answer chemically?
2. Why might an evolutionary biologist be interested in comparing the amino acid sequence of proteins between two different species? What differences might she find when comparing species that are distantly related or closely related? Explain.
3. Some viruses carry their genetic material as DNA while others, known as retroviruses, carry their genes as RNA. Virologists studying emerging viruses that might infect humans are interested in discovering which types would be the most difficult for our immune system to fight. Viruses that mutate quickly and thus, are able to thwart our immune defenses are the most concerning. Which of these two viruses, DNA or RNA, do you think mutate faster? Explain.

Answer 1

1. Trans fatty acids do not have a kink in the molecule. Because of that the fatty acids pack closure in the lipid layers. This helps in solidification of the fat under low temperatures. Leading to settling in the body and causing damage to the body. Kink is important to maintain health. Trans fats raise the bad cholesterol levels.

2. The amino acid sequence is determined by the nucleotide sequences in the DNA. Closure the organisms related, there will be less differences in the nucleotide sequences and hence aminoacids also will be mostly similar with fewer differences. So it is indirectly telling about the DNA nucleotide sequences.

3. RNA viruses mutate faster. This is because RNA viruses are single stranded and the nucleotides are more exposed to the surroundings and the RNA replication does not have proof reading. Any errors during replication are not corrected. That is why the RNA viruses mutate faster. More mutations will cause more changes in the viral particles which the immune system fail to recognize and attack. So RNA viruses are more difficult to control.