EOCT Review

1. EOCT Review Domain I - Cells

2. Prokaryotes vs. Eukaryotes • Prokaryotes • Cells that do not have a nucleus or any other membrane-bound organelles • Kingdoms Eubacteriaand Archaebacteria • Eukaryotes • Cells that do have a nucleus and other membrane-bound organelles • Kingdoms Plantae, Animalia, Fungi, and Protista

3. Living vs. Nonliving • All living things: • Must obtain energy and nutrients • Maintain homeostasis • Respond to stimuli • Reproduce • Are made of cells

4. Cells must have boundaries… • Plasma membrane • A boundary between the cell and its external environment • Flexible and allows the cell shape to vary • Controls movement of materials into and out of the cell • Found in all cells • Cell wall • An additional boundary outside the plasma membrane • Thicker and inflexible • Protects the cell and gives it shape • Found in plants, fungi, most bacteria, and a few protists • Not found in animals

5. Question #1 • Unlike prokaryotic cells, eukaryotic cells have the capacity to • assemble into multicellular organisms • establish symbiotic relationships with other organisms • obtain energy from the Sun • store genetic information in the form of DNA

6. Question #2 • Inside eukaryotic cells are membrane-bound structures called • cell walls • cilia • organelles • cytoplasm

7. Nucleus • Control the cell • Regulates all cellular processes • Contains the DNA • Where DNA is replicated • Where RNA is made • Related structures: • Nuclear envelope • Chromatin • Nucleolus

8. Ribosomes • Where proteins are made • Found freely floating in the cytosol or attached to the Rough ER

9. Endoplasmic Reticulum (ER) • Rough ER • Has ribosomes on the surface • Aids in the production of proteins • Transports proteins to the Golgi body or imbeds them in the plasma membrane • Smooth ER • Does not have ribosomes • Produces lipids for the plasma membrane • Drug detoxification

10. Endoplasmic Reticulum (ER)

11. Golgi Apparatus • Also known as the Golgi body or Golgi complex • Modifies, sorts, packages, and transports proteins • Sends proteins to their final destination inside or outside the cell

12. Chloroplasts • Found in plant cells, some bacteria, and some protists • Use energy from sunlight to produce sugars during photosynthesis • Contains the green pigment chlorophyll

13. Mitochondria • Release energy (ATP) from food molecules during cellular respiration • Known as the ‘powerhouse’ of the cell

14. Identify the cell parts…

15. Identify the cell parts…

16. Plasma Membrane • Helps to maintain homeostasis by controlling what enters and leaves the cell • Selective permeability – allows certain materials to pass through the cell while keeping others out

17. Cell Transport • Passive transport – does not use energy • Diffusion – the movement of substances across the membrane from high concentration to low concentration • Osmosis – the diffusion of water • Facilitated transport – a carrier molecule transports a large substance across the membrane • Active transport – requires energy • Materials are moved from an area of low concentration to an area of high concentration • Ex. Sodium-potassium pump • Endocytosis – a process in which a cell surrounds and takes in material • Exocytosis – a process by which materials leave the cell

18. Question #3 • Which of the following examples illustrates osmosis? • Water leaves the tubules of the kidney in response to the hypertonic fluid surrounding the tubules. • Digestive enzymes are excreted into the small intestine. • White blood cells consume pathogens and cell debris at the site of an infection. • Calcium is pumped inside a muscle cell after the muscle completes its contraction.

19. Enzymes • Proteins that are catalysts – speed up reactions by lowering the activation energy • Features: • They do not make processes happen that would not take place on their own. They just make the processes take place faster. • Enzymes are not permanently altered or used up in reactions. • The same enzyme works for the forward and reverse directions of a reaction. • Each enzyme is highly selective about its substrate

20. Enzymes • Substrates are molecules which a specific enzyme can chemically recognize and to which it can bind • Substrates undergo chemical changes to form new substances called products • Each substrate fits into an area of the enzyme called the active site

21. Lock-and-key mechanism • Once the enzyme-substrate complex is formed, the enzyme holds the substrate in a position where the reaction can occur

22. Enzymes • Enzymes have an optimum pH and temperature that they work best at • If the pH or temperature is too high or too low, then the enzyme will not function properly or not at all

23. Question #4 • Food is commonly refrigerated at temperatures 2°C to 7°C to slow the rate of spoilage by bacteria. Which of the following best explains why refrigeration at these temperatures slows the spoilage of food? • Bacteria that cause food spoilage are killed by these low temperatures. • Bacteria that cause food spoilage multiply rapidly at these temperatures. • The enzymes in bacteria that cause food spoilage are not active at these temperatures. • The enzymes in bacteria that cause food spoilage are denature at these temperatures.

24. Carbohydrates • A simple sugar or a molecule composed of two or more simple sugars • The ratio of carbon, hydrogen, and oxygen atoms is 1:2:1 • Monosaccharide – one sugar • Oligosaccharide – short chain of two or more sugars • Polysaccharide – many sugars • Ex. Glucose, sucrose, starch, cellulose

25. Lipids • Organic compounds that have more carbon-hydrogen bonds and fewer oxygens than carbohydrates • Fats, oils, and waxes • Insoluble in water • Long-term energy storage, insulation, and protective coatings

26. Proteins • Composed of amino acids • Made of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur • Important in muscle contraction and in the immune system • Transport oxygen in blood • Component of cell membranes • Ex. Collagen, enzymes, hemoglobin, insulin, antibodies

27. Nucleic Acids • Store information in cells in the form of a code • Make up ATP, NAD+, NADP+, DNA, and RNA • Made up of nucleotides which contain: • A five-carbon sugar • A nitrogen-containing base • A phosphate group

28. Question #5 • The assembly of proteins in a cell takes place in the • nucleus • vacuoles • cytoplasm • mitochondria

29. Question #6 • Which of the following is an organism whose cell(s) lack(s) membrane-bound organelles? • nucleolus • chromatin • eukaryote • prokaryote

30. Question #7 • In all reptiles, birds, and mammals, the processes of excretion, water and salt balance, and the regulation of pH in body fluids are controlled by the kidneys. This is an example of the organism maintaining • reabsorption • homeostasis • insulation • hibernation

31. Question #8 • Proteins are long chains or polymers made up of • nucleotides • carbohydrates • amino acids • lipids

32. Question #9 • Which of the following molecules provides the greatest amount of energy per gram of mass when metabolized? • carbohydrate • nucleic acid • protein • lipid

33. Question #10 • Which of the following environmental changes can cause an increase in the rates of reactions in cells? • increased temperature • decreased enzyme concentration • increase activation energy requirement • decreased diffusion rates

34. Answers • A • C • A • C • C • D • B • C • D • A

35. Information and images obtained from: • http://www.doe.k12.ga.us/ci_testing.aspx?PageReq=CI_TESTING_EOCT&SubPageReq=GUIDES • Google image search • Campbell, Neil A. and Reece Jane B (2001). "6". Biology. Benjamin Cummings. • Miller, Kenneth R. and Levine Joseph S. (2002). Biology. Prentice Hall.