biology 2013. experiment – when an idea is tested. independent variable – measured (time or...

Mid-Term ReviewBiology 2013

Scientific Method and Inquiry

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.

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.

a) What is Smither’s hypothesis?a) The magic juice will improve worker’s

productivityb) What is the independent variable?

a) The time the workers were asked to staple papers

c) What is the dependent variable?a) The amount of papers the workers stapled.

d) What are his controls?a) Same amount of workers in each test groupb) Same amount of juice in test groupc) Same amount of time workers could staple.

e) What should Smither’s conclusion be?a) The juice had no, if not a negative effect on

the worker’s productivity.

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.

.

4. What is the diff erence 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.

Levels of Organization

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!

6. What is homeostasis?

• Maintaining a stable internal environment

Biomolecules and Enzymes

7. What are the four biomolecules?

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

9. Draw a quick picture of each biomolecule.

10. Biomolecules are polymers, correctly pair them with their monomer.

• Monomers• Glucose• Amino acid•Nucleotide

• Polymers• Starch• Protein• Nucleic acid (DNA, RNA)

13. Enzymes are which biomolecule?

•Proteins!

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

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

amount of activation energy.

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

Cell Structure

17. What are the three part of the cell theory?

1. All living things are made up of one or more cells.

2. The cell is the basic unit of life3. All cells come from pre-existing cells

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

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.

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

ProkaryoteEukaryote

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

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

Diffusion and Osmosis

23. What is diffusion?

• The movement of a substance from high to low concentration.

24. What is osmosis?

• The movement of WATER from high to low concentration.

• 25. Under normal conditions, water will move from HIGH concentration to LOW concentration.

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

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.

28. What is active transport?• When a substance needs energy (ATP)

to move against the concentration gradient. (low to high or uphill concentration)

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

Endocytosis

Specialized Cells

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!

31. Why would it be necessary for a leaf cell to have lots of chloroplasts?

• Because leaves are the plants sites of photosynthesis!

Cell Cycle (Interphase, Mitosis, Cytokinesis)

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

32. What are the three “main” events of the cell cycle?

• INTERPHASE

• MITOSIS• CYTOKINES

IS

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

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

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!

• 36. The M phase of the cell cycle consists of both mitosis and cytokinesis.

• Mitosis refers to nuclear division, whereas cytokinesis refers to cell division.

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!

38. What is cancer? What causes cancer?

• Uncontrolled cell growth.• Is caused by internal(genetic) factors

as well as environmental factors

DNA and DNA Replication

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!

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

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!

42. What is the monomer of DNA? What three things make up a nucleotide found in DNA?

• NUCLEOTIDES!• 5 CARBON SUGAR (HOUSE)• PHOSPHATE (CHIMNEY)•NITROGEN BASE (GARAGE)

43. Figure 12.1

• Figure 12-1 shows the structure of a(an) DNA

• Using Figure 12-1, the structure labeled X is a NUCLEOTIDE

• The structure (shape) for Figure 12-1 is a

DOUBLE HELIX

44. 3’TATCCGGACTTC 5’• What is the nucleotide base sequence that

complements the section of DNA modeled above?

•5’ATAGGCCTGAAG3’

45. The diagram to the side shows the process of DNA REPLICATION.

46. What are the steps of DNA replication? (What happens first?) Describe the end result of DNA replication, how do the strands compare?

End result: two new strands, each with one parent and one new strand.

47. Do all living things have DNA? If so, what then makes an organism completely unique from another?

• All living things have DNA

• The difference is in the SEQUENCE of the bases!

Protein Synthesis and Mutations

48. . What are the two stages of protein synthesis? Where does each stage take place in the cell?

• Transcription and Translation

• Transcription occurs in the nucleus

• Translation occurs in the cytoplasm, at the ribosome.

49. What is the end result of transcription? What is the purpose of this molecule?

• mRNA strand.• To send the message of the gene to the ribosome where it can be translated into a protein!

50. Transcribe the following DNA strand in to mRNA T-A-C-G-G-C-G-A-T-A-T-T

• A-U-G-C-C-G-C-U-A-U-A-A

51. What is the end result of translation? Translation requires the use of tRNA, what is the purpose of this molecule?

• A PROTEIN!

52. Translate the following mRNA strand into its correct amino acid sequence A-U-G-C-U-A-A-A-A-U-A-GMET – LEU – LYS - STOP

53. Chains of amino acids

(polypeptide) form a PROTEIN!

53. What is a mutation? What is the difference between a point mutation and a frameshift mutation?

54. Draw an example of a substitution mutation. Draw an example of an insertion mutation. Draw an example of a deletion mutation.

55. How do mutat i ons c hange the ma k i ng o f a pr ote in?

•They can change the amino acid sequence…

56. How do environmental factors play a role in gene expression?

The coloration of the fur is dependent on environmental temperature.

Ecology

57. Which of the following is a long-term effect on the removal of the redfish from the ecosystem represented by this food web?

A decline in the amount of phytoplankton, sea grass and seaweed

58. The diagram represents a pyramid of biomass in an aquatic environment. Explain what happens to energy as you go up the pyramid.

As you go up the pyramid, the amount of energy available for the next level decreases by a factor of 10.

59. How much energy is passed from the producers to the primary consumers if the producers start with 1000J (Kcal/sq.m)of energy?

60. A tapeworm is a worm with no digestive tract. They live in the intestines of other animals and absorb food that has already been digested by their host causing harm. What type of nutritional relationship do tapeworms exhibit?

•Parasitism

61. Orchids grow on large tropical trees. The orchids depend on the support offered by the trees, but do not harm the trees. What type of symbiotic relationship is this?• Commensalism

62. The symbiotic relationship between a flower and the insect that feeds on its nectar is an example of _____________.• Mutualism

63. What crucial role do fungi play in the ecosystem?

• Decomposers

64. What is a density-dependent limiting factor? Give an example.

• Factors within the environment that affect populations because of their size. Ex. Disease, Famine

65. What is a density-independent limiting factor? Give an example.• Factors within the environment that

affect populations regardless of their size. Ex. Weather

66. What is the difference between primary and secondary succession?

Secondary Succession - starts from soil, usually occurs after a disturbance, like a fire or humans clearing forests.

Primary Succession - starts from bare rock, the first life form, the pioneer species, is typically lichens and moss, they eventually develop soil, then larger types of vegetation can take hold; the largest form of vegetation in an area is called its climax community

67. The only way carbon dioxide (CO2) is removed from the atmosphere is through what process?

• Photosynthesis

Photosynthesis and Cellular Respiration

68. What is the equation for photosynthesis? Where in the cell does this process happen?

• In the chloroplasts of plant cells

69. What is the equation for cellular respiration? Where in the cell does this process happen?

• In the mitochondria of all eukaryotic cells

70. Why are photosynthesis and cellular respiration often considered opposites?• The reactants of one equation are the

products of the other.

Ghosts of Reviews Past….

Genetics and Meiosis

56. Define genotype and phenotype. Give an example of both.

57. Organisms that have two identical alleles for a particular trait are said to be HOMOZYGOUS. What does it mean to be heterozygous?

• TO HAVE 2 DIFFERENT ALLELES FOR A TRAIT.

58. Botanists cross a heterozygous (Pp) plant having purple flowers with a homozygous (pp) plant having white flowers. About what percentage of the offspring will have purple flowers? White flowers?

50% Purple50% white

59. A male and female bison are both heterozygous for normal skin pigmentation (Aa). What is the probability that they will produce an albino offspring (aa)? What is the genotypic ratio? What is the phenotypic ratio?

25% chance of albino offspring.G: 1:2:1P: 3:1

60. Gregor Mendel, the father of genetics, used pea plants to study the inheritance of traits. If a plant that is homozygous tall and wrinkled was crossed with a short, wrinkled plant, which percentage of genotypes would most likely be found in the first-generation offspring?

• TTss X ttss• Ts Ts Ts Ts x ts ts ts ts• All would be Ttss

61.INCOMPLETE DOMINANCE occurs when one allele for a gene is not completely dominant over another causing blending of phentypes. Four-o'clock flowers show incomplete dominance for flower color. Purebred white flowers (WW) crossed with purebred red flowers (RR) produce?

62. A cross of a black chicken with a white chicken produces all black and white speckled offspring. This type of inheritance is known as CODOMNIANCE. Color coat for roan(red and white spotted) cows shows codominance. If a cow with a white coat is crossed with a cow with a roan (red and white spotted) coat, what percentage of the offspring will be red?

63. Assume that a woman who is heterozygous for type A blood and a man who is heterozygous for type B blood are expecting a child. What is the chance that their child will have type O blood? What chance will their child have type A blood?

25% chance of type O, 25% chance of type A

64. Assume that a woman who is homozygous for type A blood and a man who is AB are expecting a child. What are the possible outcomes of blood type for their child?

• AA X AB = 50% AA OR 50% AB

AAAA A

65. What are sex-linked traits? On what chromosome are sex linked traits carried?

• Traits that are passed down from mother to children on the X chromosome.

66. Be able to read and explain a pedigree chart. What are the possible outcomes at ???????????????

???????????? = 25% CARRIER FEMALE, 25% NORMAL FEMALE 25% MALE WITH COLORBLINDNESS , 25% NORMAL MALE

67. What is the significance of meiosis to the evolution of a species?

• Meiosis adds to the VARIATION within a species

68. What is the end result of meiosis? Draw a picture!

RESULT = 4 UNIQUE HAPLOID DAUGHTER CELLS

69. What is crossing over? And why is it significant to meiosis?

• Crossing over shuffles genes! Adds to VARIATION!