Dr. Reichlers Bio 301L 9:30-11:00amPrint Name:________________KEY_________
In-class Exam #1 25 Sept. 2001
Answer each question as succinctly as possible in the space provided. You may use the back if you need more space. If you use a drawing as part of your answer, be sure to also include a written explanation. Each question is worth 3 pts, unless otherwise noted, for a total of 100 points possible for this exam. Read each question carefully, and dont hesitate to ask if a question seems unclear.
Reductionist. The question is about events at the molecular or cellular level. Looking at the smallest components will give answers to this question.
By having multiple hypotheses, we can not become attached to just one. Also by eliminating hypotheses, we are less likely to be led astray by positive, but incorrect results.
b. If potassium forms an ionic bond with chloride to make the salt KCl, and if this makes the potassium positive and the chloride negative, how many electrons does the potassium have now?
KCl is held together by ionic bonds that can be interrupted by the + and - charges. CO2 is covalently bonded, and will not disassociate when put near other charges.
Dr. Reichlers Bio 301L 9:30-11:00am In-class Exam #1 25 Sept. 2001 Name:_____________KEY________
3. a. Describe what happens to an individual water molecule that causes it to be polar.
The electron sharing in the covalent bond is unequal, so the electrons are closer to the oxygen more time than they are close to the hydrogen. Thus the O has an overall - charge and the H a + charege. Because these + and - charge are unequally distributed, the water molecule is polar.
A soluble protein is likely made of mostly polar AA'a, while a non-soluble protein is made of non-polar AA's.
As water freezes it rises leaving liquid water below where organisms can survive during cold temp's.
Chemical. Covalent bonds are being broken.
There are more H+ than OH-.
One neutron breaks into a proton and electron. The electron leaves the molecule, and the proton remains so now the element has changed to one with 16 protons.
Dr. Reichlers Bio 301L 9:30-11:00am In-class Exam #1 25 Sept. 2001 Name:________ KEY ____________
The half-life of phosphate-32 is about 14 days, and the half-life of calcium-45 is 165 days
32P, it is less stable and therefore releasing more radioactivity more quickly.
45Ca, it is more stable, and will continue to emit radioactivity slower and therefore longer.
When beta-particles enter a cell, it commonly hits a water molecule, breaking the water molecule apart. This releases a single O molecule, called activated O. this is very reactive and will cause improper/unregulated chemical reactions thereby damaging the cell.
By using radioactive dating you can check how much of a radioactive element is left in the dye versus how much should be present, carbon-14 is commonly used. This will tell you how long ago the plant was killed to make the dye.
Nucleic acids (nucleotides)-Store information
Lipids-Serve as barrier/membrane
Dr. Reichlers Bio 301L 9:30-11:00am In-class Exam #1 25 Sept. 2001 Name:_________ KEY ___________
They are all made of small units that must be covalently bonded together to form a functional unit. Lipids are not covalently bound to each other.
Separating the strands only involves breaking ionic bonds. Cutting a chain means cutting covalent bonds.
Transfer the info from DNA to make proteins.
DNA carries the info, and if it is damaged all the proteins made after it will be wrong. Damaged proteins can be remade from the DNA.
Any three of:
Signal-sending or receiving information
Transport-moving things in/out of cell or around organism
Enzyme-allow chemical reaction to take place
Structural-support cell or organism
Sugars are polar, and their increased levels interfere with the ionic bonds that give the protein its 3-D shape, so it unfolds.
Dr. Reichlers Bio 301L 9:30-11:00am In-class Exam #1 25 Sept. 2001 Name:________ KEY ___________
Polar head (hydrophilic), nonpolar tail (hydrophobic). Groups of lipids form a bilayer with the tails to the inside and heads outside. This makes a membrane that excludes water and other polar molecules.
Membranes act as barriers but cells need to move things in and out. So proteins in the membrane act to facilitate and regulate this transport.
By releasing it from cells via glucagon and transport proteins or eating it.
Their cells are insensitive to insulin, so giving insulin will not help.
DNA codes for proteins such as insulin, glucagon, the transporters, etc. Also, problems in the DNA can lead to diabetes.
Create multiple hypotheses. Design experiments that ELIMINATE one or more of the hypotheses.