please answer all parts of the question 1. In this problem, we will develop macr
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please answer all parts of the question
1. In this problem, we will develop macroscopic analogies to mechanical components in the cell, in order to get a better feel for the scales involved. You may need to look up some numbers as you go. Show your calculations and indicate any additional values used Imagine scaling up a typical eukaryotic cell (let's say a fibroblast, to be concrete) and all its constituent parts to the size of a large house (roughly 15m across) (a) First we'll consider the nucleus and the genome in this analogy i. In terms of size, the nucleus of the cell will resemble which of the following in ii. In terms of its thickness, the DNA chain in this analogy will resemble: a thread ii. What total length of analogous chain must fit inside this house to represent your imaginary house: a marble, a basketball, a chair, a room? a piece of spaghetti, an extension cord, a snake, or a plumbing pipe? the entire human genome? Give an approximate example of a comparable macroscopic distance (e.g.: the length of the UCSD campus) iv. Nucleosomes, in this analogy, will most closely resemble: a grain of sand, a v. Consider what would happen if you wrapped a strand of raw spaghetti twice al differences between DNA and spaghetti that marble, a basketball, a chair? around a marble, like DNA around a nucleosome. How does a cell manage to do this? Comment on the m make this possible and explain where the energy for such deformation comes rom (b) Now consider the rest of the cell. i. What will be the diameter of a microtubule in this analogy? ii. In our analogy, the thickness of the cell membrane would be comparable to: a sheet of paper, a notebook, a wall? Page 1 of4 Physics 177/277 Problem Set 1 Due 4/12/2017 ii. Mitochondria in our analogy would be roughly the size of: a marble, a basket- ball, a chair, a room?Explanation / Answer
(1) (a) (i) Nucleus is the central part of an eukaryotic cell and it controls all major functions of living cell. A nucleus is round in shape and contains genetic components. For this reason, a nucleus will resemble a basketball in the imaginary house.
(ii) DNA chain is extremely thin and resembles a piece of spaghetti.
(iii) If we unwind all the DNA chains in a cell total length would be about 6 feet. This is comparable to a room in an imaginary house. The entire human genome would fit inside the entire house.
(iv) Nucelosome is the fundamental unit of DNA and it resembles a marble.
(v) A strand of raw spaghetti is wrapped around a marble just like DNA is wrapped around a nucleosome in a living cell. DNA chain has a double helical structure and this helps it to wrap around a nucleosome. However, a strand of raw spaghetti doesn't have a helical structure. The energy for deformation, while wrapping the nucleosome, comes from the helical tension within the DNA chain.
(b) (i) A microtubule is extremely thin and its diameter resembles a grain of sand.
(ii) A cell membrane is a very thin outer covering of a living cell. It resembles a sheet of paper in macroscopic analogy.
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