Study Guide for Biology Midterm



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Study Guide Key for Biology Exam on Organic Molecules and Cells

Directions: On a separate piece of paper answer all of the following questions. Your answers should be thorough and detailed! This study guide is not graded, but I highly suggest that you complete the study guide by Monday, October 3, 2011.

1. What is life made of? Cells Define what a cell is. A cell is the smallest living unit capable of functioning independently.

2. How many bonds can carbon have? ____4____Fill in the short hand version of this molecule to make it a full atom version by filling in the carbon and hydrogen atoms:

[pic][pic]

3. What are the 4 types of organic macromolecules that we discussed in class? What are the monomers for each polymer? Describe how you can recognize each type of macromolecule. Be Able to Identify Each Type.

E.g.

|Polymer |Monomer |Description |

|Nucleic Acids |Nucleotide |A nucleotide has a phosphate, sugar, and nitrogenous base (A,T, C, G, U) |

|(DNA and RNA) | | |

|Carbohydrates |Monosaccharide |Saccharides are usually carbon rings. They have the molecular formula |

| | |CnH2nOn |

|Proteins |Amino Acid |There are 20 different amino acids. Each amino acid has an amino group (NH2)|

| | |and a carboxyl group (COOH) |

|Lipids |Fatty acids |Have long carbon chains |

4. What type of macromolecule is depicted in the picture below? Protein Label the amino end, carboxyl end, and peptide bond.

[pic]

Amino End Peptide Bond Carboxyl End

5. Add another monomer to this molecule to increase its size, show the product below:

|[pic] |+ |[pic] |

6. What is the chemical formula for a monosaccharide? CnH2nOn

7. What molecule is removed from monomers to make a polymer? Water What is this reaction called? Dehydration Reaction When polymers are broken into monomers, what molecule is added? Water What is this type of reaction called? Hydrolysis Reaction

8. What are cells made of? (HINT: Define atom, element, molecule, organic molecule, macromolecule, and organelles and give an example of each. Pictures help)

E.g.

|Atom |The smallest unit of an element |[pic] |

|Element |A type of atom defined by the number of protons it has. |[pic] |

|Molecule |Two or more atoms held together by covalent bonds |[pic] |

|Organic Molecule |A molecule with carbon atoms |[pic] |

|Macromolecule |A large molecule |[pic] |

|Organelles |Compartments within a cell |[pic] |

9. What does it mean to be alive? Organisms that can grow, reproduce, evolve, respond to the environment, maintain homeostasis What is an organism? A living thing

10. Define eukaryote. A eukaryote has a nucleus and membrane bound organelles. An example of a eukaryote is a human. What is the difference between a prokaryote and a eukaryote? A prokaryote does not. An example of a prokaryote is bacteria.

11. What are the three domains of life? Define each and give an example.

Bacteria: prokaryotes that we encounter every day like E.coli.

Archea: prokaryotes usually found in extreme environments like deep sea vents.

Eukarya: eukaryotes including, plants, animals, fungus, and protists.

12. What is biodiversity? All the variety of life on earth Why is biodiversity important? Because organisms provide us with the food we eat, the air we breathe, the water we drink, etc. How are humans impacting biodiversity? Humans are destroying habitats, polluting, spreading diseases and invasive species, hunting, etc.

13. Convert 5,000uL to __5mL.

14. Convert 0.05L to _50,000uL.

15. Describe the function of each organelle and draw it: nucleus, ribosomes, smooth endoplasmic reticulum, rough endoplasmic reticulum, golgi apparatus, mitochondria, chloroplasts, cytoskeleton, flagella, and cell wall.

[pic]

Nucleus: holds the DNA

Ribosomes: Make proteins

Smooth ER: Makes lipids

Rough ER: Has ribosomes; site of protein synthesis

Golgi Apparatus: Packages and sorts proteins

Mitochondria: Site of cellular respiration (ATP is made here)

Chloroplasts: Site of photosynthesis; glucose is made here

Cytoskeleton: Made of microtubules and microfilaments; gives the cell shape and structure.

Flagella: Tail of the cell that helps the cell move. It is made of microtubules

Cell Wall: A membrane on the outside of the plasma membrane. Found in plants, bacteria, fungi and some protists. It gives the cell rigidity.

16. How do plant and animal cells differ? Plant cells have chloroplasts, a cell wall, and a large central vacuole. Animal cells don’t have any of these.

17. Draw a cell membrane. Label the phospholipids and the membrane proteins. Label the phosphate head and the fatty acid tails of the phospholipids. Label the hydrophobic and hydrophilic regions.

[pic]

18. What is the function of a cellular membrane? It separates the cell from the outside environment. It regulates what goes in and out. When we say that the plasma membrane is semi permeable, what does that mean? Some things can pass through it and other things cannot.

19. What molecules can pass through the membrane? Small non-charged molecules. What cannot? Charged big molecules.

20. Define osmosis, diffusion.

Osmosis: the diffusion of water across a semi permeable membrane

Diffusion: The movement of molecules from a high concentration to a low concentration until they reach equilibrium.

Molecules diffuse passively from areas of HIGH concentration to areas of LOW

concentration.

21. In an experiment designed to study osmosis, several pieces of dialysis tubing were filled with sucrose solutions of varying concentrations and placed in beakers containing distilled water. The weight and direction of water movement is determined by weighing the bags before and after placing them in distilled water. The data is recorded below:

Table 1: Mass of Dialysis Tubing After Submersion in Water

|Tube Number |Tube contents (beaker contents) |Mass (g) |Mass (g) |Mass (g) |Mass (g) |

| | |0 minutes |15 minutes |30 minutes |45 minutes |

|1 |Distilled water |22.3g |22.4g |22.2g |22.3g |

| |(distilled water) | | | | |

|2 |10% Sucrose |24.8g |25.3g |25.7g |26.4g |

| |(distilled water) | | | | |

|3 |40% Sucrose |25.1g |26.3g |27.5g |28.9g |

| |(distilled water) | | | | |

|4 |Distilled water |22.7g |21.3g |20.5g |19.8g |

| |(40% sucrose) | | | | |

a. Why does the mass of Tube 3 increase, while the mass of Tube 4 decreases? Tube 3 is in a hypotonic solution, so water diffuses into the tube by osmosis. Tube 4 is in a hypertonic solution, so water diffuses out of the tube by osmosis.

b. Why does the mass of Tube 1 remain relatively unchanged? Tube 1 is in an isotonic solution

c. When comparing the solution in Tube 1, with the solution in the beaker, the solution in the beaker is isotonic, hypertonic or hypotonic? Explain. Isotonic because it has the same amount of solutes in the tube as in the beaker.

d. When comparing the solution in Tube 3, with the solution in the beaker, the solution in the beaker is isotonic, hypertonic or hypotonic? Explain. Tube 3 is in a hypotonic solution because there is less solutes in the beaker compared to the tube.

22. Animal Cells are approximately 0.9% solute solution. What would happen if you put an animal cell in a solution of 4% solute solution? It would shrivel because the cell is in a hypertonic solution.

23. Define passive transport, and active transport. Explain two types of passive transport and draw a picture of each.

Passive transport: when molecules diffuse across a membrane from high concentration to a low concentration (down their concentration gradient). This does not require energy.

Active transport: when molecules diffuse across a membrane from low concentration to a high concentration (against their concentration gradient). This does require energy.

[pic]

24. The molecule that stores energy is called ATP. What are the subunits of this molecule? Adenosine and three phosphates. When is energy released from this molecule? When the phosphate bond is broken. What is this energy used for? Lots of different cellular processes.

25. What is photosynthesis? The use of light energy to make sugar (glucose).

26. Write the general equation for photosynthesis.

6CO2 + 6H2O + light ( C6H12O6 + 6O2

27. What green pigment molecule traps light in photosynthesis? chlorophyll

28. What are the two phases of photosynthesis? Where do they each occur? What stage requires light? What is produced in each stage?

1. The Light Reactions. This occurs in the thylakoid membrane of the chloroplasts. This stage requires light. ATP and NADPH is produced in this stage. O2 is also made.

2. The Calvin Cycle. This occurs in the stroma of the chloroplasts. This stage DOES NOT require light. Glucose is produced here.

29. Draw a diagram of both phases of photosynthesis. Label the two phases, the thylakoid membrane, the grana, the stroma, the molecular inputs and products for each phase.

a. Draw the electron transport chain in the light reactions of photosynthesis.

Include a phospholipid bilayer; ATP synthase; light; electrons moving; H2O; H+; NADPH; the movement of H+; and ATP.

b. Draw the second phase of photosynthesis. Include: CO2, Ribulose biphosphate, ATP, NADPH, GP3, glucose

Jesse’s picture:

[pic]

Extra Pictures from the web

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[pic]

30. How do all cells harvest the energy in food? Cellular Respiration

31. What is the equation for cellular respiration?

C6H12O6 + 6O2 ( 6CO2 + 6H2O + ATP

32. What are the three stages of cellular respiration? Where are they located in the cell? Which stages require O2?

1. Gylcolysis. This is located in the cytosol.

2. Citric Acid Cycle (Krebs). This is located in the mitochondrial matrix. This requires oxygen.

3. Oxidative Phosphorylation and the Electron Transport Chain. This is located in the inner mitochondrial membrane. This requires oxygen.

33. Draw a picture of where each of the three stages + the PDC of cellular respiration occur in the cell. Show where each stage is located in the cell, how much ATP is produced in each stage, how many electron carriers are made at each stage and what are the starting molecules and products. Include an electron transport chain with a phospholipid bilayer, proteins, electrons moving, H2O, H+, NADH, the movement of H+, ATP synthase, and ATP.

Jesse’s Picture

[pic]

Pictures form the web:

[pic]

[pic]

34. What ion is used to make a chemiosmotic gradient in the mitochondria and chloroplast to make ATP? H+

35. What happens if there is no oxygen to complete cellular respiration? Fermentation. What are the two types of fermentation? Lactic Acid Fermentation and Alcoholic Fermentation. What is made in each? Lactic Acid. Ethanol and CO2. Explain how NAD is recycled. In glycolysis, NAD+ is converted to NADH because it picks up an electron. In fermentation it loose an electron (is oxidized) to become NAD+ again. Draw a picture showing glycolysis and fermentation in the cell.

[pic]

After you are finished with this study guide, spend some time going over and over each question and answer. A good study strategy is to write the answers of the study guide over and over again until you have them memorized. Or you can make flashcards for each question. Go over the flashcards until you can “spit back” the information without looking at the cards

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