Domain I Review Cells Microscopes Compound Microscope Used

Domain I Review Cells

Microscopes • Compound Microscope – Used to magnify objects – Bends or refracts light to make objects appears closer – Common magnifications: • 40 x, 100 x, 400 x • Stereoscope – Allows for binocular viewing of large specimens – Can be used for thick specimens – Creates a 3 D view of specimen – Common magnifications: • 10 x to 20 x

Microscopes • Scanning Electron Microscope – Use electrons to magnify objects up to 10, 000 times – View surface of objects – Creates a 3 D view of specimen, but cannot view living specimens (process kills them) • Transmission Electron Microscope – Sees through objects – Magnifies up to 100, 000 times – Can view only dead or inanimate objects

Characteristics of Life • All living things: – Must obtain energy and nutrients – Maintain homeostasis – Respond to stimuli – Reproduce – Are made of cells

Introduction to the Cell • Cell is the smallest living unit of life • Unicellular (Prokaryote) • Multicellular (Eukaryote) 10/7/2020 SB 1 a 5

Discovery of the Cell • Robert Hooke (1600’s) – 1 st person to see a cell – Looked at a cork • Anton van Leeuwenhoek (1700’s) – 1 st person to see a living cell – Looked at pond water 10/7/2020 SB 1 a 6

In 1838 German botanist Matthias Schleiden concluded that cells make up all parts of a PLANT. In 1839 German zoologist Theodor Schwann claimed that ANIMALS are made of cells. http: //www. rkm. com. au/posters/

Cell Theory In 1858, German physician Rudolph Virchow determined that cells come from other cells. 1. All living things are composed of cells 2. Cells are the basic unit of life 3. Cells come only from other cells 10/7/2020 SB 1 a 8

Cell Organelles • The term organelle means “little organ. ” • Organelles are small, specialized structures in a cell. Just like your organs in your body, they carry out different jobs so the cell can function. • You should know the organelles in eukaryotic (complex) cells, like plant and animal cells.

Prokaryotes vs Eukaryotes • Prokaryotes – Less complex cells (simple) – No membrane bound organelles; contains cell membrane, cytoplasm, and ribosomes – DNA and RNA are present, but they are free floating; DNA is found in circular strands called plasmids – Smaller cells – Example: Bacteria • Eukaryotes – More complex cells – Has membrane bound organelles-mitochondria, nucleus, vacuole, chloroplasts, etc. – Has a nucleus that contains DNA; DNA is in the shape of a double helix (twisted ladder) – Larger cells – Example: Plant and Animal Cells

Similarities Between Prokaryotic and Eukaryotic Cells • Both have DNA (just different shapes/locations) • Both have ribosomes • Both have cell membrane, cytoplasm, may contain cell wall Video Review: https: //www. youtube. com/watch? v=RQ-SMCm. WB 1 s

Organelles to Know Nucleus • Structure: Sphere-shaped organelle containing most of the cell’s genetic information (DNA) • Function: Controls cell; where RNA is made, DNA replication occurs; has nuclear membrane Plasma (Cell) Membrane • Structure: Double membrane (bilayer) of lipids • Function: Controls what goes in and out of cell (selectively permeable); Supports and protects cell; maintains chemical balance within cell

Cellular Structure and Function

Organelles to Know Mitochondria • Structure: Oval shaped; folded inner membrane for extra surface area • Function: Produce energy in cell (ATP) through the process of respiration Vacuole • Structure: Sac-like organelle • Function: Stores water and other important materials • NOTE: There are many small vacuoles in animal cells. Plants have one large vacuole that stores water for turgor pressure

Organelles to Know Ribosomes • Structure: Tiny organelles scattered throughout the cell • Function: Produces proteins during protein synthesis Cell Wall (Plant Only) • Structure: Rigid, cellulose based structure that surrounds plasma membrane in plant cells • Function: Additional protection and support for the cell

Organelles to Know Chloroplast • Structure: Green, oval organelles in plant cells • Function: Perform photosynthesis for the cell by converting sunlight into glucose; contains chlorophyll Golgi Apparatus • Structure: flattened membranous sacs • Function: Modifies, sorts, packages, and transports proteins and lipids; sends proteins to final destination inside and outside of cell

Organelles to Know Endoplasmic Reticulum • Structure: membranous sheets and tubules that begin near the nucleus and extend across the cell • Function: – Rough: Aids in the production of proteins; transports proteins to the Golgi body or imbeds them in the plasma membrane – Smooth: Does not have ribosomes; produces lipids for the plasma membrane; drug detoxification

Organelles to Know Lysosomes • Structure: spherical bodies found within cell • Function: Contain digestive enzymes; Digests: food particles, bacteria, worn out cell parts; only found in animal cells Cilia and Flagella • Structure: fingerlike projections that extend from some cells • Function: Help the cell move – Cilia: Short, hair like; lots of them – Flagella: Long, tail like; generally one long one

Plastids • Store pigments – Chloroplasts • Chlorophyll = green – Chromoplasts • Carotenes = orange • Xanthophyll = yellow – Leucoplasts • Store starches 10/7/2020 SB 1 a 19

Things to Note: • The structure of the organelle determines its function – For example, the mitochondria has a folded inner membrane to increase the surface area. More surface area = more energy production for the cell. – What other examples can you think of? • Organelles may appear in higher numbers in different cells – For example, you may see more mitochondria in muscle cells where more energy is needed, or more chloroplasts on the leaf cells of plants where they have access to sunlight. • The organelles work together to make the cell function. – All organelles play a role. Consider the nucleus which controls the production of proteins, which are made on ribosomes in the cytoplasm, where the proteins can then be used as enzymes during respiration in the mitochondria. Video Review: https: //www. youtube. com/watch? v=3 n. Bt. Y 6 LR 030

How Do Cells Maintain Homeostasis? • Homeostasis means to maintain balance in a cell. This is required for life! • Cells have buffers that regulate p. H in the cell • The plasma membrane regulates what goes into and out of the cell using active and passive transport. This helps maintain homeostasis!

Active Transport • Active Transport: The cell transports molecules against the concentration gradient using protein pumps. Required energy! (ATP) – Endocytosis: cell takes in material from its environment (enters cell) • Phagocytosis – cell eating • Pinocytosis – cell drinking – Exocytosis: cell removes materials from inside the cell (leaves cell)

Passive Transport • Passive Transport: The cell moves molecules with the concentration gradient. Requires no energy. – Diffusion: Particles moves from high to low concentration – Facilitated Diffusion: Particles move from high to low concentration through proteins (carrier or channel) – Osmosis: The movement of water from high to low concentration across a membrane • 3 Osmotic solutions: Isotonic, hypotonic, and hypertonic

Cellular Structure and Function

Osmosis Solutions

Cellular Structure and Function

How Do Unicellular Organisms Maintain Homeostasis? • Chemotaxis: Movement toward or away from chemicals • Phototaxis: Movement toward or away from light • All of these adaptations allow the cell to maintain homeostasis.

Enzymes • Are proteins that act as catalysts - speeding up a chemical reaction by lowering the activation energy • Features: – Do not create processes that would not take place on their own. They just make the processes take place faster! – Are not permanently altered or used up in reactions. – Can only catalyzes only one specific type of reaction – Highly selective about substrate (lock and key mechanism) – Optimum temperature (body temp. ), denatured if temperature or p. H changes

Substrates • 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

Chemistry in Biology

Carbohydrates • Made of Carbon, Hydrogen, and Oxygen in a 1: 2: 1 ratio • Includes sugars and starches • The monomer (or building block) of are monosaccharides, or simple sugars • Carbohydrates are our main source of energy • Monosaccharides = simple carbohydrates – Glucose – sugar needed for energy production – Galactose – milk sugar – Fructose – fruit sugar • Disaccharide = 2 monosaccharides joined together – Sucrose = table sugar • Polysaccharides = many monosaccharides joined together – Storage forms of glucose • In plants = starch • In animals = glycogen, then changed to fat if not used – Animals store excess sugar in muscles and liver for energy

Lipids are made mostly of carbon and hydrogen Include fats, oils, and waxes The building blocks of most lipids are fatty acids and glycerol Lipids: – Can be used to store energy – Make up part of the structure of cell membranes – Are chemical messengers – Body insulation and cushioning for organs. – Waterproof coverings. – Cholesterol • Saturated fats—Bad fats in diet. Comes from animals. – Examples: butter, lard, mayonnaise, fat in meat • Unsaturated fats—Good fats in diet. Comes from plants. – Polyunsaturated—more than 1 double bond – Examples : vegetable oil, peanut oil, olive oil • •

Proteins • Proteins are made of Carbon, Hydrogen, Oxygen, and Nitrogen • Comes from animals. (Meat, cheese, milk, eggs, and nuts) • The building blocks of proteins are amino acids – 20 different amino acids can make many different kinds and shapes of proteins. • Proteins: – – – Control the rate of reactions Regulate cell processes Form bones and muscle Transport substances into or out of cells Help fight disease • NOT USED FOR ENERGY!

Nucleic Acids • Contain Hydrogen, Oxygen, Nitrogen, Carbon, and Phosphorus • The building blocks are nucleotides • Nucleic acids store and transmit hereditary information • Ex. DNA and RNA – DNA – stores genetic information – RNA – builds proteins

Chemistry in Biology

Question #1 Placing wilted lettuce in cold water will make it crisp again. Which statement best describes what happens to restore the lettuce to its original condition? a. Water left the lettuce cells by diffusion. b. Water entered the cells of the lettuce by osmosis. c. Osmosis caused salts to enter the lettuce cells. d. Salts in the leaf caused water to leave the cells.

Question #2 What feature of eukaryotic cells has enabled them to develop more specific functions than prokaryotic cells? a. b. c. d. Nucleus Organelles Genetic material (DNA) Larger cell size

Question #3 In prokaryotic cells, where does the conversion of fuel particles into usable energy occur? a. b. c. d. Cytoplasm DNA Mitochondria Ribosomes

Question #4 Which organelle is similar to the section of a factory that organizes, boxes, and ships the final product? a. b. c. d. Chloroplast Endoplasmic Reticulum Golgi Apparatus Mitochondria

Question #5 In which structure is light energy captured and converted to chemical energy? a. b. c. d. Chloroplast Lysosome Nucleus Vacuole

Question #6 How does osmosis occur between the two solutions separated by the selectively permeable membrane? a. b. c. d. Sugar moves to the left. Sugar moves to the right. Water moves to the left. Water moves to the right.

Question #7 Which type of cellular transport does not require an input of energy? a. active transport b. endocytosis c. exocytosis d. facilitated diffusion

Question #8 Which diagram shows a cell in a hypotonic solution? A. B. C.

Question #9 _______ is the net movement of particles from an area where there are many particles of the substance to an area where there are fewer particles of the substance. a. Diffusion b. Endocytosis c. Exocytosis d. Equilibrium

Question #10 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? a. Bacteria that cause food spoilage are killed by these low temperatures. b. Bacteria that cause food spoilage multiply rapidly at these temperatures. c. The enzymes in bacteria that cause food spoilage are not active at these temperatures. d. The enzymes in bacteria that cause food spoilage are denature at these temperatures.

Question #11 Muscle cells require a great amount of energy. Which would you expect to find in large numbers in muscle cells? a. centrioles b. endoplasmic reticulum c. mitochondria d. ribosomes

Question #12 In what type of cell would you most likely expect to find numerous lysosomes? a. A plant cell that stores food, enzymes, or other materials b. A plant cell that uses light energy for photosynthesis c. A single-celled organism that moves around its environment d. A white blood cell that digests bacteria and viruses

Question #13 Why are the carrier proteins that move substances across a plasma membrane from a region of higher concentration to a region of lower concentration called pumps? a. They require energy to move substances against a concentration gradient. b. They open and close to allow substances to diffuse across the plasma membrane. c. They help with the osmosis of water through the plasma membrane. d. They pump water into the cell, causing the pressure within the cell to increase.

Question #14 How does an enzyme increase the rate of a chemical reaction? a. It acts as a reactant. b. It reduces the amount of heat produced. c. It increases the amount of product. d. It lowers the activation energy.

Question #15 Which element do almost all biological molecules contain? a. carbon b. nitrogen c. phosphorus d. sodium

Question #16 What are fats, oils, and waxes composed of? a. lipids b. nucleotides c. polypeptides d. sugars

Question #17 What are the monomers that make up proteins? a. amino acids b. fatty acids c. glycerols d. nucleotides

Question #18 Look at the following figure. Determine what the upward curve represents. a. activation energy b. reactants c. products d. enzymes

Question #19 The assembly of proteins in a cell takes place in the a. b. c. d. nucleus vacuoles cytoplasm mitochondria

Question #20 Which of the following is an organism whose cell(s) lack(s) membrane-bound organelles? a. b. c. d. nucleolus chromatin eukaryote prokaryote

Question #21 In all reptiles, birds, and mammals, the processes of excretion, water and salt balance, and the regulation of p. H in body fluids are controlled by the kidneys. This is an example of the organism maintaining a. b. c. d. reabsorption homeostasis insulation hibernation

Question #22 Which of the following molecules provides the greatest amount of energy per gram of mass when metabolized? a. b. c. d. carbohydrate nucleic acid protein lipid

Question #23 Which of the following environmental changes can cause an increase in the rates of reactions in cells? a. b. c. d. increased temperature decreased enzyme concentration increase activation energy requirement decreased diffusion rates

Question #24 Which characteristic does a virus have in common with a eukaryotic cell? a. b. c. d. Cell wall Mitochondrion Nucleic acid Ribosome

Question #25 About one in one million people are born with dyskeratosis congenita. This disease affects many areas of the body. It causes fingernails and toenails to grow abnormally and discoloration of the skin. Dyskeratosis congenita is caused by a mutation in a gene responsible for the production of ribosomes; therefore, ribosome functioning is impaired. Which cell process would be most directly affected by this disease? a. b. c. d. the production of energy the production of proteins the removal of substances the breakdown of chemicals

Question #26 Which graph shows the most effective enzyme reduction of the amount of required activation energy?

Question #27 A student is demonstrating how water moves across cell membranes to maintain homeostasis. The student uses dialysis bags, which are semipermeable and model cell membranes. The student fills each of the three bags with 100 m. L of a 10% salt solution and ties the end of each bag. In Beaker 1, the student places 200 m. L of a 5% salt solution. In Beaker 2, the student places 200 m. L of a 10% salt solution. In Beaker 3, the student places 200 m. L of a 20% salt solution. What kind of environments are in Beakers 1, 2, and 3? a. Beaker 1: hypertonic, Beaker 2: hypotonic, Beaker 3: isotonic b. Beaker 1: hypertonic, Beaker 2: isotonic, Beaker 3: hypotonic c. Beaker 1: isotonic, Beaker 2: hypertonic, Beaker 3: hypotonic d. Beaker 1: hypotonic, Beaker 2: isotonic, Beaker 3: hypertonic

Question #28 Individuals who lack lactase are unable to break down the sugar lactose. Which term best describes lactase? a. enzyme b. fatty acid c. lipid d. starch

Information and images obtained from: • https: //www. gadoe. org/Curriculum-Instructionand. Assessment/Documents/Milestones /Study. Resource%20 Guides/Study. Guide_BIO_s 15 GAEOC_08. 14. 15. pdf • Biggs, A. , et al. (2008). Biology. Mc. Graw-Hill. • Campbell, Neil A. and Reece Jane B (2001). "6 th ed. ". Biology. Benjamin Cummings. • Miller, Kenneth R. and Levine Joseph S. (2002). Biology. Prentice Hall.