Category: 1st Semester

Protein Synthesis Puzzle

 

Protein Synthesis
Across 2. a series of three mRNA nucleotides that codes for an amino acid 3. coded for by DNA and made of amino acids 7. process of assembling amino acids into polypeptides in the ribosomes 9. RNA that copies DNA in the nucleus 10. use to translate mRNA transcripts into proteins 11. UGA, UAA, and UAG codons 12. RNA that carries amino acids to be linked together to make proteins 15. site of transcription Down 1. both DNA and RNA are these types of compounds 2. where ribosomes are found 4. series of three bases on tRNA that code for an amino acid 5. base on RNA that replaces thymine 6. holes in the nuclear membrane where mRNA leaves to move to the ribosome 8. methionine codon (AUG) 13. RNA that makes up ribosomes along with proteins 14. site of protein synthesis

 

Pterosaur Reconstruction Bi

 

Pterosaur Reconstruction

 

Introduction:

A common sight during the Cretaceous period was the soaring through the air of a large fur-covered creature called the pterosaur. Pterosaur means flying lizard. Wings of some  pterosaurs were longer than the wings of a small plane. This creature lived on cliffs at the edge of lagoons and would sail from its nest to catch prey.  The bones of one pterosaur, Scaphognathus crassirostris, were discovered in 1826 by the German scientist, August Goldfuss.  The fossilized bones were located in a limestone quarry and were unbroken.  Scaphognathus crassirostris was approximately the size of a large bat with a broad jaw and short tail.

Objective:

Students will reconstruct the skeleton of S. crassirostris and draw conclusions about its method of movement, feeding habits, and other adaptations.

Materials:

Scissors, tape, construction paper, glue, metric ruler, pencil

                     
Fossil Cast of S. crassirostris                                    

 

Procedure:

  1. Use the drawings of S. crassirostris bones to cut out and reassemble a model of the flying reptile.
  2. Glue the model bones to a sheet of construction paper being sure to center the model and keep all bones on the paper.
  3. Use the metric ruler to measure the complete wingspan of the organism (tip to opposite tip).
  4. Complete the characteristics in data table 1.

Data:

Table 1

 

Characteristics of S. crassirostris
Wingspan (centimeters)?
Jaw Shape?
Teeth adapted for?
Arms & hands adapted for?
Number of bones in lower arm?
Number of bones making up skull?
Number of fingers?
Finger adaptations?

 

Questions:

  1. The bones of the lower arm and lower leg are fused (joined together). How might this be an adaptation for flight?
  2. What would be the main function of the long bones of S. crassirostris little finger?
  3. Noting the shape of the teeth and where S. crassirostris lived, what did it probably eat?
  4. Name 3 characteristics that adapted S. crassirostris to flight.
  5. The bones of S. crassirostris were hollow. How was this an adaptation?
  6. The flap of skin that made up the wing of S. crassirostris was very delicate and could tear easily. How could this cause a problem with S. crassirostris competing with other gliding reptiles?

 

 

Properties of Water

 

Properties of Water

 

Introduction:

Water’s chemical description is H2O. As the diagram to the left shows, that is one atom of oxygen bound to two atoms of hydrogen. The hydrogen atoms are “attached” to one side of the oxygen atom, resulting in a water molecule having a positive charge on the side where the hydrogen atoms are and a negative charge on the other side, where the oxygen atom is. This uneven distribution of charge is called polarity. Since opposite electrical charges attract, water molecules tend to attract each other, making water kind of “sticky.” As the right-side diagram shows, the side with the hydrogen atoms (positive charge) attracts the oxygen side (negative charge) of a different water molecule. (If the water molecule here looks familiar, remember that everyone’s favorite mouse is mostly water, too). This property of water is known as cohesion.

All these water molecules attracting each other mean they tend to clump together. This is why water drops are, in fact, drops! If it wasn’t for some of Earth’s forces, such as gravity, a drop of water would be ball shaped — a perfect sphere. Even if it doesn’t form a perfect sphere on Earth, we should be happy water is sticky. Water is called the “universal solvent” because it dissolves more substances than any other liquid. This means that wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, and nutrients.

Water, the liquid commonly used for cleaning, has a property called surface tension. In the body of the water, each molecule is surrounded and attracted by other water molecules. However, at the surface, those molecules are surrounded by other water molecules only on the water side. A tension is created as the water molecules at the surface are pulled into the body of the water. This tension causes water to bead up on surfaces (glass, fabric), which slows wetting of the surface and inhibits the cleaning process. You can see surface tension at work by placing a drop of water onto a counter top. The drop will hold its shape and will not spread.

In the cleaning process, surface tension must be reduced so water can spread and wet surfaces. Chemicals that are able to do this effectively are called surface active agents, or surfactants. They are said to make water “wetter.” Surfactants perform other important functions in cleaning, such as loosening, emulsifying (dispersing in water) and holding soil in suspension until it can be rinsed away. Surfactants can also provide alkalinity, which is useful in removing acidic soils.

Pre-Lab Questions (Click here)

Materials:

Box of small paper clips, small plastic container, eyedropper, cup, stirring rod, water, liquid soap, plastic tray

Procedure (Part A) Cohesiveness of Water:

  1. Estimate how many paper clips will fit into a completely full cup of water. Record this number in data table 1.
  2. Place your small container on a tray to contain any water that may spill.
  3. Fill a plastic cup with tap water.
  4. Pour tap water from your cup into your small container.
  5. Continue to add water by eyedropper until the top surface appears rounded.
  6. Slowly add paper clips one at a time to the cup keeping count of all paper clips that you add.
  7. Stop adding paper clips to the container whenever water spills from the top.
  8. Record your paper clip count. Compare the actual number of paper clips to the estimated number.

Procedure (Part B) Soap’s effect on Surface Tension:

  1. Again estimate how many paper clips will fit into a completely full cup of soapy water. Record this number in data table 2.
  2. Place your small container on a tray to contain any water that may spill.
  3. Fill a plastic cup with tap water.
  4. Add several drops of liquid soap & use a stirring rod to mix.
  5. Pour soapy water from your cup into your small container.
  6. Continue to add soapy water by eyedropper until the top surface appears rounded.
  7. Slowly add paper clips one at a time to the cup keeping count of all paper clips that you add.
  8. Stop adding paper clips to the container whenever water spills from the top.
  9. Record your paper clip count. Compare the actual number of paper clips to the estimated number.

Data:

Table 1

 

Cohesiveness of Tapwater
Estimated Number of Paper Clips Actual Number of paper Clips Difference
 

 

 

Table 2

 

Cohesiveness of Soapy water
Estimated Number of Paper Clips Actual Number of paper Clips Difference
 

 

 

Questions: 

1. How did your estimated number compare to your actual number?

2. What happened to the surface of the water as more clips were added?

 

3. What property of water was shown in Part A?

4. How is this property of water used in nature?

5. Explain why water shows surface tension.

 

6. Explain why water is a polar molecule and include a diagram of several water molecules in a drop of water.

 

 

7. In order to clean a surface, what must happen to surface tension?

 

8. What is the job of a surfactant?

 

9. Name a surfactant used in Part B?

10. Using your data from Part B, explain what proof you gathered in Part B to support your answer to question 9.

 

 

 

Preap Cellular Respiration Study Guide

 

Cellular Respiration Review  

 

1. Most eukaryotic cells produce only about ___________  ATP Molecules per Glucose Molecule.

2. What is the process by which glucose is converted to pyruvic acid? ________________________________________

3. At the beginning of aerobic respiration, pyruvic acid bonds to a molecule called ______________________________________ to form Acetyl CoA.

4. The breakdown of pyruvic acid in the presence of oxygen is called ______________________________  _______________________.

5. With every completion of the Krebs Cycle, how many ATP Molecules are made? ________________

6. What is the waste product of the Krebs Cycle? _____________________________________________.

7. The conversion of pyruvic acid to carbon dioxide and ethanol is called ___________________________________   _____________________________________________.

8. The release of energy from food molecules in the absence of oxygen is ______________________________________     _________________________________________________________.

9. What is the byproduct of the electron transport Chain?_______________________________________________.

10. How efficient is Anaerobic Respiration? __________%  Aerobic Respiration? ____________%

11. What is the first pathway of cellular respiration called? ________________________________________________

12.What is the location of Glycolysis? _______________________________________________________

13. What is the scientific unit of Energy? ________________________________________________

14. What do you call cellular respiration in the presence of oxygen? _______________________________________  _________________________________________________________.

15. Yeast produces ______________________________ and _______________________________ in the process known as ____________________________________  ___________________________________________.

16. In cellular respiration, glycolysis proceeds the _______________________________  ___________________________.

17. In cellular respiration, more energy is transferred in the ___________________________  ________________________  _________________________________ than in any other step.

18. Glucose molecules are converted into _______________________________  _______________________ molecules in the process of glycolysis.

19. What is the location of the electron transport chain in prokaryotes? ________________  _______________________.

20. The processes of glycolysis and the anaerobic pathways is called ___________________________________.

21. What is the product of acetyl CoA and oxaloacetic acid? _________________  ___________________

22. What molecule is the electron acceptor of glycolysis? _________________________________________

23. The breakdown of organic compounds to produce ATP is known as ____________________________________  ________________________-_______________________________.

24. Glycolysis begins with glucose and produces ______________________________  _________________________.

25. An important molecule generated by both lactic acid and alcoholic fermentation is ______________________________.

26.  In the first step of aerobic respiration, pyruvic acid from glycolysis produces CO2, NADH, H+, and _________________________________  _____________________________________.

27. The electron transport chain is driven by two products of the Krebs Cycle – ______________________  and  ___________________________.

28. What happens to electrons as they are transported along the electron transport chain? _________________________________________________________________

29. The energy efficiency of aerobic respiration (including glycolysis) is approximately ______________  __________________________________________________.

30. Where in the mitochondria do the reactions of the Krebs cycle occur? _____________________________   ___________________________________________________________

31. Where in the mitochondria is the electron transport chain located? _____________________________          __________________________________________________

32. In alcoholic fermentation, ethyl alcohol is produced from _______________________________  ______________________________________.

33.  ____________________________________, and _______________________________ supply electrons and protons to the electron transport chain.

34. Cellular respiration takes place in Two Stages: _______________________________________, then ________________________________________  ________________________________.

35. Water is an end product in the ________________________________________________________________
___________________________________________________________________.

36. In cellular respiration, a two-carbon molecule combines with a four-carbon molecule to form citric acid as part of the _____________________________________________________________________________________.

37. When glycolysis occurs, a molecule of glucose is ___________________________________________.

38. The name of the process that takes place when organic compounds are broken down in the absence of oxygen is _____________________________________________ or _______________________________________.

39. Energetic electrons that provide the energy for the production of most of a cell’s ATP are carried to the electron transport chain by _______________________________ and __________________________________________.

40. _______________________________________ is a biochemical pathway of cellular respiration that is anaerobic.

41. Glucose is split into smaller molecules during the biochemical pathway called __________________________________.

42. In the absence of oxygen, instead of oxidative respiration following glycolysis, glycolysis is followed by ______________________________________________________.

43. During fermentation, either ethyl alcohol and carbon dioxide or _______________________________________ is formed.

DIRECTIONS: Answer the questions below as completely and as thoroughly as possible. Answer the question in essay form (not outline form), using complete sentences. You may use diagrams to supplement your answers, but a diagram alone without appropriate discussion is inadequate.

1. How does aerobic respiration ultimately depend on photosynthesis?

2. Explain the role of oxaloacetic acid with respect to the cyclical nature of the Krebs cycle.

3. Glycolysis produces only 3.5% of the energy that would be produced if an equal quantity of glucose were completely oxidized.  What has happened to the remaining energy in the glucose?

4. Why do most cells produce fewer than 38 ATP molecules for every glucose molecule that is oxidized through aerobic respiration?

5. What happens to electrons that accumulate at the end of the electron transport chain?

6. What role does chemiosmosis play in aerobic respiration?

7. What condition must exist in a cell for the cell to engage in fermentation?

8. How is the synthesis of ATP in the electron transport chain of mitochondria similar to the synthesis of ATP in chloroplasts?

9. The fourth step of glycolysis yields four ATP molecules, but the net yield is only two ATP molecules.  Explain this discrepancy.

10. Under what conditions would cells in your body undergo lactic-acid fermentation?

11. What role does oxygen play in aerobic respiration? What molecule does oxygen become a part of as a result of aerobic respiration?

12. Where in the mitochondrion do protons accumulate, and what is the source of the protons?