| Elements in Living Things |
Now write the symbol for each element in the proper place on the periodic table.
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Category: My Classroom Material
DNA Replication Lab
Modeling DNA Replication
Introduction
Within the nucleus of every cell are long strings of DNA, the code that holds all the information needed to make and control every cell within a living organism. DNA, which stands for deoxyribonucleic acid, resembles a long, spiraling ladder. It consists of just a few kinds of atoms: carbon, hydrogen, oxygen, nitrogen, and phosphorus. Combinations of these atoms form the sugar-phosphate backbone of the DNA — the sides of the ladder, in other words.
Other combinations of the atoms form the four bases: thymine (T), adenine (A), cytosine (C), and guanine (G). These bases are the rungs of the DNA ladder. (It takes two bases to form a rung — one for each side of the ladder.) A sugar molecule, a base, and a phosphate molecule group together to make up a nucleotide. Nucleotides are abundant in the cell’s nucleus. Nucleotides are the units which, when linked sugar to phosphate, make up one side of a DNA ladder.
During DNA replication, special enzymes move up along the DNA ladder, unzipping the molecule as it moves along. New nucleotides move in to each side of the unzipped ladder. The bases on these nucleotides are very particular about what they connect to. When the enzyme has passed the end of the DNA, two identical molecules of DNA are left behind. Cytosine (C) will “pair” to guanine (G), and adenine (A) will “pair” to thymine (T). How the bases are arranged in the DNA is what determines the genetic code.
When the enzyme has passed the end of the DNA, two identical molecules of DNA are left behind. Each contains one side of the original DNA and one side made of “new” nucleotides. It is possible that mistakes were made along the way — in other words, that a base pair in one DNA molecule doesn’t match the corresponding pair in the other molecule. On average, one mistake may exist in every billion base pairs. That’s the same as typing out the entire Encyclopedia Britannica five times and typing in a wrong letter only once!
Objectives
The replication of DNA before cell division can be shown using paper templates for the components of DNA nucleotides.
Materials
- Cut Outs of basic subunits of DNA
- Colors or markers
- Scissors
- Tape or glue
- Paper & pencil
Procedure:
- Cut out all of the units needed to make the nucleotides from the handout provided.
- Color code the Nitrogenous bases, phosphorus, and deoxyribose sugar as follows —
Adenine = red, Guanine = green, Thymine = yellow, Cytosine = blue, Phosphate = brown, and Deoxyribose = purple. - Using the small squares and stars as guides, line up the bases, phosphates and sugars.
- Now glue the appropriate parts together forming nucleotides.
- Construct DNA model using the following sequence to form a row from top to bottom – cytosine (topmost), thymine, guanine, and adenine (bottommost).
- Let this arrangement represent the left half of your DNA molecule.
- Complete the right side of the ladder by adding the complementary bases. You will have to turn them upside down in order to make them fit.
- Your finished model should look like a ladder.
- To show replication, separate the left side from the right side, leaving a space of about 6-8 inches.
- Use the remaining nucleotides to complete the molecule using the left side as the base.
- Build a second DNA model by adding new nucleotides to the right half of the original piece of the molecule.
- Tape the nucleotides together to form 2 complete DNA ladders.
Questions
1. Of the 4 bases, which other base does adenine most closely resemble?
2. List the 4 different nucleotides.
3. Which 2 molecules of a nucleotide form the sides of a DNA ladder?
4. If 30% of a DNA molecule is Adenine, what percent is Cytosine?
5. What does the term replication mean?
6. What is another name for adenine and three phosphate molecules attached to it?
Elephants Can’t Jump
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It is a known fact that, unlike other animals, elephants can not jump! The bones in an elephant’s feet are too tightly packed and they’re too heavy.
On this page, you will find interesting questions about other living things. Use the Google search engine on this page to help find the answers & then e-mail me your correct answer for test coupons.
| The scientific name for the giraffe is Giraffa camelopardalis. What does this Latin name mean? |  |
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Double Helix Paper
Race for the Double Helix
Write a 2 page synopsis of the movie, Double Helix, using the following outline for your summary. Your grade will be based on the amount of specific facts you include from the movie.
Introduction:
- How did Watson meet Crick
- Where did Watson and Crick work
- Where did Franklin work
- The “race”
- The “prize”
“One of the Believers”
- Who were the believers
- What did they believe in
- How was Watson’s sister to help
- Why was Linus Pauling a threat
“Buried treasure”
- Why was Wilkins helpful
- Why wasn’t Franklin helpful
- Who was Franklin ’s assistant
- What types of DNA did Franklin find
- What type did she spend most of her research time on and why?
- Tell about the 1st model Watson and Crick built and what was the problem
“She Hasn’t Seen It”
- What did Franklin miss
- Why didn’t Wilkins go ahead and build the model
- Watson & Crick had to get permission from the head of the Cavendish Institute for what to be done
- Who determined how the bases fit together and how did they do this?
- Where did they end up putting the phosphates
- How were Watson & Crick able to finally build the DNA model
- What was Wilkins part?
Conclusion
- Who got credit for finding the structure of DNA
- What was Rosalind Franklin’s response when she saw the model that Watson & Crick built
Energy in food
| The Heat is On – The Energy Stored in Food |  |
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| Introduction:
Plants utilize sunlight during photosynthesis to convert carbon dioxide and water into glucose (sugar) and oxygen. This glucose has energy stored in its chemical bonds that can be used by other organisms. This stored energy is released whenever these chemical bonds are broken in metabolic processes such as cellular respiration. Cellular respiration is the process by which the chemical energy of “food” molecules is released and partially captured in the form of ATP. Cellular respiration is the general term which describes all metabolic reactions involved in the formation of usable energy from the breakdown of nutrients. In living organisms, the “universal” source of energy is adenosine triphosphate (ATP). Carbohydrates, fats, and proteins can all be used as fuels in cellular respiration, but glucose is most commonly used as an example to examine the reactions and pathways involved. Marathon runners eat a large plate of pasta the night before a competition because pasta is a good source of energy, or fuel for the body. All foods contain energy, but the amount of potential energy stored will vary greatly depending on the type of food. Moreover, not all of the stored energy is available to do work. When we eat food, our bodies convert the stored energy, known as Calories, to chemical energy, thereby allowing us to do work. A calorie is the amount of heat (energy) required to raise the temperature of 1 gram (g) of water 1 degree Celsius (°C). The density of water is 1 gram per milliliter (1g/ml) therefore 1 g of water is equal to 1 ml of water. When we talk about caloric values of food, we refer to them as Calories (notice the capital “C”), which are actually kilocalories. There are 1000 calories in a kilocalorie. So in reality, a food item that is listed as having 38 Calories has 38,000 calories. Calories are a way to measure the energy you get from the food you eat. Just as pasta can provide a runner energy to run a marathon, a tiny peanut contains stored energy that can be used to heat a container of water. For this lab exercise, you will indirectly measure the amount of Calories in couple of food items using a calorimeter. A calorimeter (calor = Latin for heat) is a device that measures the heat generated by a chemical reaction, change of state, or formation of a solution. There are several types of calorimeters but the main emphasis of all calorimeters is to insulate the reaction to prevent heat loss. We will be using a homemade calorimeter modeled after a constant-volume calorimeter. A particular food item will be ignited, the homemade calorimeter will trap the heat of the burning food, and the water above will absorb the heat, thereby causing the temperature (T) of the water to increase. By measuring the change in temperature (∆T) of a known volume of water, you will be able to calculate the amount of energy in the food tested
Objective:
In this experiment, you will measure the amount of energy available for use from three types of nuts, a plant product. This process of measuring the energy stored in food is known as calorimetry. Materials: Procedure:
Results:
Questions & Conclusion:
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