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Introduction:
The first cells to arise in oceans of Earth were prokaryotes. The genetic material of these cells was not contained within a nucleus. Thus, the cells obtained energy and nutrients by absorbing organic molecules from their environment.
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Answer to Problem 1FIB
Correct answer:
In the early atmosphere, there were no oxygen the first cells must have derived energy by anaerobic
Explanation of Solution
There was no oxygen gas in the primitive atmosphere, so cells must have metabolized the organic molecules anaerobically. Thus, anerobic bacteria were the earliest cells. Simpler molecules such as water, and carbon dioxide would still be very abundant.
Eventually, some cells evolved the ability to utilize the energy of sunlight to carry out the synthesis of high energy complex molecules from simplex molecules releasing oxygen as a byproduct.
Oxygen is potentially very dangerous to living organisms as it reacts with organic molecules resulting in their break down. Many anaerobic bacteria of today perish when exposed to oxygen which acts as deadly poison for them. Then the great advance in evolution allowed some organisms to use this oxygen in metabolism. This ability prevented them from chemical action of oxygen and allowed them to channelize the oxygen’s destructive power, through aerobic respiration to generate useful energy in the huge amount for cell.
Oxygen present in the early atmosphere was destruction until evolution of some cells that channelized its power for the aerobic respiration. The amount available to the cell is vastly increased when oxygen is utilized for metabolism of food.
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Chapter 17 Solutions
Biology
- 10. Your instructor will give you 2 amino acids during the activity session (video 2-7. A. First color all the polar and non-polar covalent bonds in the R groups of your 2 amino acids using the same colors as in #7. Do not color the bonds in the backbone of each amino acid. B. Next, color where all the hydrogen bonds, hydrophobic interactions and ionic bonds could occur in the R group of each amino acid. Use the same colors as in #7. Do not color the bonds in the backbone of each amino acid. C. Position the two amino acids on the page below in an orientation where the two R groups could bond together. Once you are satisfied, staple or tape the amino acids in place and label the bond that you formed between the two R groups. - Polar covalent Bond - Red - Non polar Covalent boND- yellow - Ionic BonD - PINK Hydrogen Bonn - Purple Hydrophobic interaction-green O=C-N H I. H HO H =O CH2 C-C-N HICK H HO H CH2 OH H₂N C = Oarrow_forwardFind the dental formula and enter it in the following format: I3/3 C1/1 P4/4 M2/3 = 42 (this is not the correct number, just the correct format) Please be aware: the upper jaw is intact (all teeth are present). The bottom jaw/mandible is not intact. The front teeth should include 6 total rectangular teeth (3 on each side) and 2 total large triangular teeth (1 on each side).arrow_forward12. Calculate the area of a circle which has a radius of 1200 μm. Give your answer in mm² in scientific notation with the correct number of significant figures.arrow_forward
- Describe the image quality of the B.megaterium at 1000X before adding oil? What does adding oil do to the quality of the image?arrow_forwardWhich of the follwowing cells from this lab do you expect to have a nucleus and why or why not? Ceratium, Bacillus megaterium and Cheek epithelial cells?arrow_forward14. If you determine there to be debris on your ocular lens, explain what is the best way to clean it off without damaging the lens?arrow_forward
- 11. Write a simple formula for converting mm to μm when the number of mm's is known. Use the variable X to represent the number of mm's in your formula.arrow_forward13. When a smear containing cells is dried, the cells shrink due to the loss of water. What technique could you use to visualize and measure living cells without heat-fixing them? Hint: you did this technique in part I.arrow_forward10. Write a simple formula for converting μm to mm when the number of μm's are known. Use the variable X to represent the number of um's in your formula.arrow_forward
- 8. How many μm² is in one cm²; express the result in scientific notation. Show your calculations. 1 cm = 10 mm; 1 mm = 1000 μmarrow_forwardFind the dental formula and enter it in the following format: I3/3 C1/1 P4/4 M2/3 = 42 (this is not the correct number, just the correct format) Please be aware: the upper jaw is intact (all teeth are present). The bottom jaw/mandible is not intact. The front teeth should include 6 total rectangular teeth (3 on each side) and 2 total large triangular teeth (1 on each side).arrow_forwardAnswer iarrow_forward
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