Mid-Term Review

1. Mid-Term Review Biology 2013

2. Scientific Method and Inquiry

3. 1. What is an experiment? What is an independent variable? What is a dependent variable? What is a control? • Experiment – when an idea is tested. • Independent Variable – measured (time or temp.) • Dependent variable – manipulated variable. (WHAT you are measuring…) • Control – part of the experiment that is kept constant – for comparison.

4. 2. Evaluating an Experiment • Smithers thinks that a special juice will increase the productivity of workers. • He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). • Group A is given the special juice to drink while they work. • Group B is not given the special juice. • After an hour, Smithers counts how many stacks of papers each group has made. • Group A made 1,587 stacks, Group B made 2,113 stacks.

5. What is Smither’s hypothesis? • The magic juice will improve worker’s productivity • What is the independent variable? • The time the workers were asked to staple papers • What is the dependent variable? • The amount of papers the workers stapled. • What are his controls? • Same amount of workers in each test group • Same amount of juice in test group • Same amount of time workers could staple. • What should Smither’s conclusion be? • The juice had no, if not a negative effect on the worker’s productivity.

6. 3. How do you increase the validity of an experiment ? • How can we make this a good experiment? • Use a large sample size • Use controls! • Test only 1 variable at a time • Repeat experiment to see if you come up with the same conclusion every time.

7. . 4. What is the difference between a hypothesis and a theory? • Hypothesis – idea that can be tested. • Theory – a hypothesis that has been tested many times and has a lot of evidence supporting it.

8. Levels of Organization

9. 5. Least complex to most complex (stopping at organism), write out the levels of organization. Give an example of each level involving either a human or plant. • Animal: Cell  tissue  organ  organ system  ORGANISM! Ex. Muscle cell, muscle tissue, heart, circulatory system, human being! • Plant: Ex. Plant cell, vascular bundle, leaf, vascular system, plant!

10. 6. What is homeostasis? • Maintaining a stable internal environment

11. Biomoleculesand Enzymes

12. 7. What are the four biomolecules?

13. 8. What is the function of carbohydrates? What is the function of lipids? What is the function of proteins? What is the function of nucleic acids? • Carbohydrates  energy • Lipids  energy and cell membranes • Proteins  build and repair • Nucleic acids  store information

14. 9. Draw a quick picture of each biomolecule.

15. 10. Biomolecules are polymers, correctly pair them with their monomer. • Monomers • Glucose • Amino acid • Nucleotide • Polymers • Starch • Protein • Nucleic acid (DNA, RNA)

16. 13. Enzymes are which biomolecule? • Proteins!

17. 14. . What is the function of enzymes? What is the term for the energy needed to get a reaction started? • Functions: • Lower activation energy • Speed up reactions

18. 15. Explain what is going on in the following graph, how did the enzyme affect the reaction? • It lowered the amount of activation energy.

19. 16. How does temperature and pH affect enzyme function? • Temperature – • Lowers or speeds up reaction • pH – • All enzymes work at their own, special (optimal) pH

20. Cell Structure

21. 17. What are the three part of the cell theory? • All living things are made up of one or more cells. • The cell is the basic unit of life • All cells come from pre-existing cells

22. 18. What are two differences between prokaryotic and eukaryotic cells? • Pro “No” Eu “Do!” • Prokaryotes • Bacteria, have no membrane-bound organelles, small • Eukaryotes • Plants and animals, have a lot of membrane-bound organelles, large

23. 19. What are two things that prokaryotic and eukaryotic cells have in common? • Prokaryotic – • Have a cell membrane, have ribosomes. • Eukaryotic – • Have a cell membrane and have ribosomes.

24. 20. Give an example of a prokaryotic cell. Give two examples of eukaryotic cells. Prokaryote Eukaryote

25. 21. What are two differences between plant and animal cells?

26. 22. What structure in the cell is responsible for maintaining homeostasis by controlling what goes in and out of the cell? • THE CELL (PLASMA) MEMBRANE

27. Diffusion and Osmosis

28. 23. What is diffusion? • The movement of a substance from high to low concentration.

29. 24. What is osmosis? • The movement of WATER from high to low concentration.

30. 25. Under normal conditions, water will move from HIGH concentration to LOWconcentration.

31. 26. Explain what type of solution the cell was placed in at A, B, and C. Be sure to include how water is moving in each type of solution. • A. HYPERTONIC • Water left the cell • B. ISOTONIC • Water moves equally into and out of the cell. • C. HYPOTONIC • Water moves into the cell

32. 27. What is facilitated diffusion? • A form of passive diffusion where a substance needs a “door” to enter a cell. Substances move from high to low concentration.

33. 28. What is active transport? • When a substance needs energy (ATP) to move against the concentration gradient. (low to high or uphill concentration)

34. 29. This is an example of what type of active transport? Endocytosis

35. Specialized Cells

36. 30. Why would it be necessary for a muscle cell to have a higher percentage of mitochondria than other cells in the body? • Because muscle cells need ENERGY!

37. 31. Why would it be necessary for a leaf cell to have lots of chloroplasts? • Because leaves are the plants sites of photosynthesis!

38. Cell Cycle (Interphase, Mitosis, Cytokinesis)

39. 32. How do cells “grow”? • Cells grow when a single cell divides into two cells and that process keeps going it is called mitosis. • When you reach adult hood and you stop growing it will still do this process because the old cells died out & dried out and new ones will replace them

40. 32. What are the three “main” events of the cell cycle? • INTERPHASE • MITOSIS • CYTOKINESIS

41. 33. What are the three parts of Interphase? What happens during each step? • G1 – cell grows and carries out metabolism. • S – DNA is copied • G2 – cell gets ready to divide

42. 34. During which stage of the cell cycle, does the cell divide and become two identical cells?

43. 35. What is mitosis? What are the 4 phases of Mitosis (M phase)? Explain what happens during each phase of mitosis and draw a picture. • Mitosis is NUCLEAR DIVISION!

44. 36. The M phase of the cell cycle consists of both mitosis and cytokinesis. • Mitosis refers to nucleardivision, whereas cytokinesis refers to cell division.

45. 37. If a cell begins with 24 chromosomes, after cell division how many chromosomes does each of the two daughter cells have? • 24? Mitosis produces IDENTICAL CELLS!

46. 38. What is cancer? What causes cancer? • Uncontrolled cell growth. • Is caused by internal(genetic) factors as well as environmental factors

47. DNA and DNA Replication

48. 39. Why will knowledge of the human genome enable scientists to better understand proteins involved in human diseases? • So that scientists can possible find cures to these diseases! • Scientists can find the genes that cause these diseases!

49. 40. Genes (DNA) contain instructions for assembling PROTEINS!

50. 41. In all plant and animal cells, the nucleus contains long molecules of DNA. Describe the function of DNA? What are the base pair rules for DNA? The function of DNA is to provide the CODE to make PROTEINS!