Life Science & Biology Projects

Question: What is The Structure of DNA?

To initially see how DNA is organized, form a model of it. This is a streamlined model of DNA, however, now it will give you the general image of how the sugars, phosphate groups, and bases all interface together to make the well known double helix state of DNA. You can make a DNA model out of an assortment of materials. In this experiment we will be using gummy bears to build a DNA model.

Materials Needed:

Mini marshmallows

Red and black hollow licorice sticks

Toothpicks

String

Gummy bears

Procedure:

1. Cut the red and black licorice sticks into one inch strips.
2. Make two equivalent lengths of licorice strands by threading the bits of licorice onto the string, exchanging the red and black pieces.
3. Assemble four unique shades of gummy bears, marshmallows, and toothpicks.
4. Combine two shades of the gummy bears together and after that match two different colors together. For instance, red and orange gummy sets could be matched together, green and yellow ones could be combined together.
5. Take a gummy bear and string it onto the toothpick. String the marshmallow onto the toothpick with the goal that it is in the focal point of the toothpick and alongside the gummy bear. String the reciprocal gummy bear onto the toothpick with the goal that it is by the marshmallow. You ought to now have a toothpick with a gummy bear marshmallow gummy bear focused on it.
6. Repeat step five to make more gummy bear marshmallow toothpicks, ensuring the gummy bears are coordinated with their correlative hues. Make the same number of these toothpicks as you have red pieces on one of your licorice strands.
7. Take one strand of licorice and begin appending the gummy bear marshmallow toothpicks to it, interfacing one of these toothpicks at each of the red pieces on the strand. At that point, take the second licorice strand and interface it to the opposite side of the toothpicks. Once more, associate the toothpicks to the red bits of licorice. You should wind up with a ladder with the red and black licorice stands making the sides of the ladder and the gummy bear marshmallow toothpicks making the rungs of the ladder.
8. Hold the candy ladder up and turn the top counterclockwise to add the twists to the ladder.

Result:

You have just made a candy model of a strand of DNA. The red licorice represents the sugar deoxyribose, the black licorice represents the phosphate groups, together they both represent the sugar-phosphate backbone of DNA.

The gummy bears represent the bases that make the code of DNA. The four unique colors are utilized to represent the four distinct bases found in DNA: adenine (A), thymine (T), guanine (G), and cytosine (C). It doesn't generally make a difference in your model the amount of a base you utilize or where it is put in the strand, yet it is imperative that bases are matched up accurately: A with T and G with C. In genuine DNA, the order does make a difference as that decides what kind of life form it is and how it will behave.

The marshmallow in the middle of the gummy bears represents the hydrogen bonds connecting the bases. This is the time when the DNA strands begin to come apart as they replicate and where the new strand associates with the first strand. Twisting the ladder at the top in a counterclockwise heading gives the DNA model its actual shape; a right-handed double helix.

Question: Can You Breed Bacteria?

Bacteria are a fascinating type of microorganism that play a large role in our lives whether we like it or not. Try growing your own sample of bacteria while monitoring how it reproduces in a short space of time. Compare your original sample with others and get proof that bacteria truly are everywhere!

What You'll Need:

Procedure:

1. Prepare your petri dish of agar.

2. Using your cotton swab, swab a certain area of your house (i.e. collect a sample by rubbing the cotton swab on a surface of your choice).

3. Rub the swab over the agar with a few gentle strokes before putting the lid back on and sealing the petri dish.

4.Allow the dish to sit in a warm area for 2 or 3 days.

5. Check the growth of the bacteria each day by making an observational drawing and describing the changes.

6. Try repeating the process with a new petrie dish and swab from under your finger nails or between your toes.

7. Dispose of the bacteria by wrapping up the petrie dish in old newspaper and placing in the rubbish (don't open the lid).

Question: What Is the Safest Way to Thaw Frozen Meat?

Summary: Often when you buy meat products at the grocery store you freeze them to make them last until they are ready for use. But they come out of the freezer frozen solid, and must be thawed before use. In this experiment we will compare 3 different thawing techniques, and see which results in the least bacteria in the meat once it is thawed.

Materials Needed: 

(Any of The Materials Highlighted in Blue are Clickable Links for Purchasing)

Pack of 5 Petri Dishes

Nutrient Agar

Disinfected Swabs

Bottle of Purified Water

Clean Chopping Board

Clean Knife

Refrigerator

Chicken Breast Bought Cold from Supermarket

3 250 Ml Beakers

Permanent Marker

Project Procedure:

1. Prepare 3 Petri dishes using agar and store them in a refrigerator. The Petri dishes are brought to room temperature before the start of experiment by taking them out of the refrigerator, label the Petri dishes as  “Room temperature”, “Fridge” and “Microwave”.

2. Using a knife and a chopping board, cut out 3 equal cubes of  chicken meat. Keep the chicken cubes inside the freezer for a day.

3. The next day, the 3 pieces of frozen chicken cubes are removed from the freezer. Remove the 3 cubes of frozen chicken from the freezer the next day. Keep the  1st cube of chicken in  the fridge for the next 12 hours to thaw . Leave The 2nd piece of chicken at the kitchen counter for the next 4 hours to thaw at room temperature. Use the microwave to thaw the 3rd piece of chicken.

4. Label the 3 beakers as “Room Temperature ”, “Fridge” and “Microwave”. Pour 100 ml of disinfected water into each beaker and soak the thawed meat in it, according to the labels on the beaker for ten minutes. Wash the swab with sterilized water and dip it into the beaker. Swipe the swab at the center of the agar surface according to the label on the beaker and Petri dish

5. Cover the Petri dishes and keep them in a cool, shaded place for the bacteria to grow, for the next 5 days.

6. Measure the diameter of the bacteria colony growth after 5 days and record it in the table provided below.

Question: What is the Bacterial Content of Milk?

Summary: For this experiment we will use Methylene blue to study the presence of aerobic bacteria in milk. Methylene blue is a blue dye that reacts to the lack of dissolved oxygen by turning translucent if there is no dissolved oxygen in a sample. Methylene blue is a good indicator for the presence of aerobic bacteria in a sample because aerobic bacteria use up oxygen.

Looking for a kit with everything you need to complete this experiment? Click Here!

Materials Needed:

(Any of The Materials Highlighted in Blue are Clickable Links for Purchasing)

Access to a stove and big pot for sterilizing equipment

5 Test Tubes

5 Test Tube Stoppers

Test tube rack

Paper towels

Calibrated pipette

50 ml graduated beaker

Pot and stove to use as a water bath

Refrigerated pasteurized milk

 Thermometer

 Kitchen tongs

 Methylene blue

Project Procedure:

1. Before starting, make sure you have sufficient temperature control with your stove. Fill a pot half-full with tepid water. Put it on the stove and raise the temperature to 98 degrees. Make sure you can keep it at this temperature for several hours.

2. Wash your hands. Cover the surfaces adjacent to your kitchen stove with paper towels. Place the test tube racks close to the stove on the paper towels.

3. Fill the pot with water and bring to a boil. Uncap your test tubes. Using your kitchen tongs, carefully drop your graduated beaker, test tubes and their caps in boiling water. Boil for one minute.

4. Remove your test tubes and graduated beaker from the water. Place the test tubes in the test tube rack.

5. Measure 9 ml of milk in the graduated beaker. Measure 9 ml milk into each test tube.

6. Using your measuring pipette, measure 1 ml methylene blue. Place the methylene blue in one of the test tubes

7. Using the kitchen tongs remove the test tube caps from the pot, and cap the test tubes. The test tube with the methylene blue is your test sample. The test tube without the methylene blue is your control. Label each test tube.

8. Pick up your test tube and gently shake it so that the methylene blue is dissolved.

9. Place each test tube in the water bath.

10. Examine the test tubes every 15 minutes for two hours and every hour afterwards. Record your observations. If it takes more than 8 hours for the milk to turn white again, the quality of the milk is excellent. If it takes 5.5 to 8 hours for the milk to turn white, then there are less than 0.5 million organisms/ml of milk. If it takes 2 to 5.5 hours for the milk to regain color, then there are 0.5 to 4 million organisms/ml of milk. If it takes 20 minutes to 2 hours, then there are 4 to 20 million organisms/ml of milk. If it takes less than 20 minutes, then there are over 20 million organisms/ml.

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