1. MID-TERM REVIEW Practice Test on HRW Website
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2. List the characteristics of life:. Organization, cells, response
List the characteristics of life: Organization, cells, response to stimuli, homeostasis, metabolism, growth and development, reproduction, and change through time.

3. Distinguish between homeostasis and metabolism and between growth, development, and reproduction Homeostasis - maintain stable internal conditions, such as temperature: Metabolism – convert nutrients into energy the body can use to sustain life. Growth and development is how an organism matures into adulthood: reproduction is how organisms produce new organisms it is essential to the existence of organisms.

4. Outline the main steps in the scientific method Making observations, asking questions, forming hypotheses, designing and conducting experiments, analyzing data, drawing conclusions, and communicating results.

5. Compare a scientific hypothesis to a scientific theory A hypothesis is an educated answer to the problem in a scientific experiment, a set of related hypothesis are true it becomes a theory.

6. State how communication in science helps prevent dishonesty and bias
When people publish the results of their experiments it allows others to test the same findings and see if they are true.

7. List the function of each of the parts of a compound light microscope
Ocular Lens – magnifies the object normally 10 times
Objective Lens – Enlarges the object to allow scientists to see stain and other parts of the specimen.
Stage – Platform that supports the slide.
Light Source – provides light to the specimen that is being observed.

8. Explain the relationship between elements and atoms
Elements are substances that cannot be broken down chemically into simpler kinds of matter. Atoms are the simplest particle of an element that retains all the properties of that element.

9. Explain the relationship between enzymes and activation energy
Activatoin energy is the amount of energy that is needed to start a reaction: Enzyme is a protein or RNA molecule that speeds up reactions.

10. Describe the structure of a water molecule
A water molecule is composed of one oxygen and two hydrogen atoms. The oxygen atom is more negative than the two hydrogen atoms. Therefore, the water molecule has a region of partial negative charge and a region of partial positive charge.

11. Explain how water’s polar nature affects its ability to dissolve substances.
In water molecule, the oxygen atom has a greater ability than the hydrogen atoms do to attract the electrons shared between the oxygen and hydrogen. The charge within the molecule is unevenly distributed.

12. Identify the role of solutes and solvents in solutions.
A solute is the substance that is being dissolved: the solvent is the substance that is dissolving the substance.

13. Identify the role of solutes and solvents in solutions.
A solute is the substance that is being dissolved: the solvent is the substance that is dissolving the substance.

14. Differentiate between acids and bases.
Acid: solution in which the number of hydronium ions is greater that the number of hydroxide ions.
Base: solution in which the number of hydroxide ions is greater than the hydronium ions.

15. Distinguish between organic and inorganic compounds.
Organic compounds are made primarily of carbon atoms: Inorganic compounds with a few exceptions do not contain any carbon atoms.

16. Explain the importance of carbon bonding in biological molecules.
Carbon can form four covalent bonds with any number of atoms, including other carbon atoms. This allows it to form molecules of different composition and shape.

17. Describe how the breaking down of ATP supplies energy to drive chemical reactions.
The removal of a phosphate from ATP releases a great deal of energy to drive other chemical reactions.

18. Distinguish between monosaccharide, disaccharides and polysaccharides.
Monosaccharide: simple sugar that contains carbon, hydrogen, and oxygen in a 1:2:1 ratio.
Disaccharides: two monosaccharide or a double sugar.
Polysaccharide: three or more monosaccharide.

19. Explain the relationship between amino acids and proteins structure.
There are 20 different amino acids, these combine through peptide bonds which form polypeptide chains. Protiens are formed by these chains of amino acids

20. Compare the structure and function of each of the different types of lipids.
Triglycerides: three fatty acids joined to one glycerol.
Phospholipids: two fatty-acid chains joined by one glycerol with a phosphate.
Wax: fatty acid chain, alcohol chain
Steroids: 4 fused carbon rings

21. Compare the nucleic acids DNA and RNA.
DNA has information for cell activities and RNA stores and transfers information for protein synthesis and are also enzymes.

22. State the three principles of the cell theory
All living organisms are composed of one or more cells, cells are the basic units of structure and function in an organism, and cells come only from the reproduction of existing cells.

23. Explain why the cell is considered to be the basic unit of life.
Because the cell is the smallest unit that can carry on all of the processes of life.

24. Describe the three basic parts of the cell eukaryotic.
The three basic parts of the eukaryotic cell are the:
Cell membrane: the cell’s outer boundary.
Cytoplasm: includes the liquid interior, cytoskeleton, and organelles of the cell.
Nucleus: the area where the cell’s genetic material is found.

25. Analyze the relationship among cells, tissue, organs, organ systems, and living organisms.
A group of similar cells working together is a tissue; tissues working together make up an organ; organs working together make up an organ system.

26. Compare prokaryotic cells and eukaryotic cells.
Prokaryotic cells, unlike eukaryotic cells do not contain membrane-bound nuclei and organelles.

27. Describe the structure and function of a cell’s plasma membrane.
Plasma Membrane functions:
Allows certain molecules to enter or leave the cell, seperates internal metabolic reactions from the external environment, allows the cell to excrete wastes and to interact within its environment.
Plasma Membrane structure:
The structure is thought of like a “mosaic” because the proteins and lipids embedded in the membrane can move laterally throughout the membrane.

28. Summarize the role of the nucleus.
The nucleus houses and protects the cell’s genetic information.

29. Identify the characteristics of mitochondria.
Tiny organelles that transfer energy from organic molecules to ATP.

30. Describe the structure and function of the cytoskeleton.
Cytoskeleton is a network of thin tubes and filaments that crisscross the cytosol.
Microtubules: maintenance of cell shape, chromosome movement, and organelle movement
Microfilaments: maintenance and changing of cell shape, muscle contraction, movement of cytoplasm, cell division
Intermediate filaments: maintenance of cell shape, anchor nucleus and other organelles, maintenance of shape of nucleus.

31. List the three structures that are found in plant cells but not in animal cells.
Animal cells, unlike plant cells, do not have cell walls, plastids, or central vacuoles.

32. Explain how equilibrium is established as a result of diffusion.
Diffusion usually leads to equilibrium, which occurs when the concentration of molecules is the same throughout a space.

33. Distinguish between diffusion and osmosis.
Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration.

34. Explain how substances cross the cell membrane through facilitated diffusion.
A molecule binds to a carrier protein on one side of the cell membrane. The carrier protein then changes its shape and transports the molecule down its concentration gradient to the other side of the membrane.

35. Distinguish between passive transport and active transport.
Passive transport moves substances down a concentration gradient with no energy use by the cell.
Active transport requires energy use by the cell to move substances against the concentration gradient

36. Compare endocytosis and exocytosis.
Endocytosis uses vesicles to bring external substances into the cell.
Exocytosis uses vesicles to release substances from the cell.

37. Explain why almost all organisms depend on photosynthesis.
Most autotrophs use the process of photosynthesis to convert the sun’s energy into chemical energy.
Heterotrophs eat photosynthetic organisms to obtain their energy, or eat other heterotrophs that have in turn eaten autotrophs.

38. Describe the role of chlorophylls and other pigments in photosynthesis.
Chlorophylls are pigments that absorb light energy during photosynthesis. Chlorophyll b assists chlorophyll a in capturing light energy. Excited electrons that leave chlorophyll a travel along two electron transport chains. The energy of these excited electrons is then used to form ATP and NADPH

39. Summarize the main events of the light reactions.

40. Explain how environmental factors influence photosynthesis.
Temperature: changes the rate at which photosynthesis occurs, Carbon Dioxide: CO2 concentration stimulate photosynthesis until the rate levels off, and Light Intensity: excites more electrons so light reactions occur more rapidly until the electrons reach their maximum rate of photosynthesis.

41. Identify the two major steps in cellular respiration.
Glycolysis: Organic compounds are converted to pyruvic acid, producing a small amount of ATP.
Aerobic Respiration: pyruvic acid is broken down and a large amount of ATP is made.

42. Compare lactic acid fermentation with alcohol fermentation.
Lactic acid fermentation produces Lactic acid.
Alcoholic fermentation produces ethyl alcohol and CO2

43. Contrast the role of glycolysis and aerobic respiration in cellular respiration.
Glycolysis: Organic compounds are converted to pyruvic acid, producing a small amount of ATP.
Aerobic Respiration: pyruvic acid is broken down and a large amount of ATP is made.

44. Describe the structure of a chromosome.
The structure of the eukaryotic chromosome begins with DNA, which is wrapped around histones and other proteins. Then these coils are further wrapped tighter and tighter until a rod-shaped chromosome is formed.

45. Identify the difference in structure between prokaryotic chromosomes and eukaryotic chromosomes
In rod-shaped eukaryotic chromosomes, DNA is wrapped around special proteins called histones and other proteins. Prokaryotic chromosomes are circular.

46. Explain the difference between sex chromosomes and autosomes
Sex chromosomes contain genes that determine gender all other chromosomes are called autosomes.

47. Distinguish between diploid and haploid cells.
Cells having two sets of chromosomes are diploid.
Cells having one set of chromosomes are haploid.

48. Describe the events of cell division in prokaryotes.
Binary fission is the division of a cell into two offspring cells, resulting in two identical daughter cells.
Prokaryotic cell exists, DNA is copied, the cell begins to divide, the cell completely divides.

49. Name the two parts of the cell that are equally divided in eukaryotes.
Both the cytoplasm and the nucleus divide.

50. Summarize the events of interphase.
G1: offspring cells grow to mature size
G2: the cell prepares for cell division
G0: a nondividing resting period

51. Describe the stages of mitosis.
Prophase: Nuclear membrane disappears, chromosomes become visible, and spindle fibers form
Metaphase: Chromosomes align at cell midline
Anaphase: The chromatids of each chromosome separate and move to the cell’s poles
Telophase: Nuclear membranes re-form, chromosomes start to uncoil, and spindle fibers disappear.

52. Explain crossing-over and how it contributes to the production of unique individuals.
Crossing over permits the exchange of genetic material between maternal and paternal chromosomes, producing a new combination of genes. This creates genetic recombination because a new mixture of genetic material is created.

53. Define sexual reproduction.
Sexual reproduction is the formation of offspring through the union of sperm and egg. Off spring produced by sexual reproduction are genetically different from the parents.

54. Relate the role of the base-pairing rules to the structure of DNA.
Hydrogen bonds between complementary base pairs helps to hold the strands together. In addition, a double-ringed purine on one strand bonds with a single ringed pyrimidine on the opposite strand, so the chains are always the same distance apart.

55. Describe how complementary base pairing guides DNA replication.
Complementary base pairing allows for two exact copies of DNA to be made from one original strand.

56. Outline the flow of genetic information in cells from DNA to proteins.
DNA  RNA  proteins

57. Compare the structure of RNA to DNA.
RNA nucleotides contain ribose (the DNA sugar is deoxyribose), the base uracil instead of thymine, an dRNA is single stranded.

58. Describe the internal and external structure of prokaryotic cells.
Capsule: protects the cell and helps the cell attach to other cells and surfaces
Cell wall: Protects the cell and gives the cell it’s shape
Cell membrane: regulates the types of molecules that move into and out of the cell

59. Continued
Cytoplasm: Contains DNA, ribosomes, an dorganic compounds that are needed for life
Chromosome: Carries genetic information from one generation to the next
Plasmid: Carries genes that are transferred through genetic recombination

60. Continued
Endospore: contains DNA; is a thick coated, resistant structure
Pilus: Helps the cell attach to surfaces and other cells during conjugation
Flagellum: Propels the cell by rotating in a whiplike motion
Outer membrane: Protects the cell against some antibiotics.

61. Summarize why viruses are not living organism.
Viruses lack key characteristics of living organisms, such as cytoplasm, organelles, metabolism, and homeostasis.

62. Describe the basic structure of viruses.
Three basic structures are helix an example is the tobacco mosaic virus, icosahendron 20 triangular faces and 12 corners, or sphere which is round.

63. Describe the lytic and lysogenic cycles of virus replication.
The Lytic cycle does not involve the integration of the viral genome into the host genome but it does result in the production of new viral particles and the host’s destruction.
The lysogenic cycle the viral genome integrates with the host genome and may stay there for a long period of time without making new virus particles or lysing the cell.

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