PROKARYOTIC AND EUKARYOTIC CELLS (AND VIRUSES) Cell Biology Standard 1c Students know how prokaryotic cells, eukaryotic cells (including those from plants and animals), and viruses differ in complexity and general structure. PROKARYOTIC CELLS (BACTERIA) Bacteria Simplest cells No membranebound organelles No nucleus DNA is found in “nucleoid region” pro = before karyo = nucleus EUKARYOTIC CELLS Membrane-bound organelles Many chemical reactions can take place at the same time Nucleus (Contains DNA) Eu = true karyo = nucleus Unicellular or multicellular organisms 2 Types: Plant & Animal Cells VIRUSES Not alive DNA or RNA surrounded by protein TRUE OR FALSE??? 1. Viruses are living and bacteria are non-living. 2. Both types of cells as well as viruses have genetic material. 3. The two types of Eukaryotic cells are plant cells and animal cells. 4. A prokaryotic cell does not have membrane bound organelles like mitochondria or endoplasmic reticulum. Eukaryotic cells are found in bacteria. Eukaryotic cells are differentiated from prokaryotic cells because eukaryotic cells A are much smaller. B have permeable membranes. C have a higher rate of reproduction. D have a nucleus. ORGANELLES OF EUKARYOTIC CELLS Cell Biology Standard 1d, 1e NUCLEUS 1D The “brain” of the cell Contains DNA that codes for ALL the proteins in your body Surrounded by the nuclear membrane Membrane has nuclear pores to let mRNA out When DNA is coiled up it’s called chromosomes When DNA is uncoiled it’s called chromatin TRANSCRIPTION 1D DNA is transcribed (copied) into messenger RNA (mRNA) mRNA leaves through nuclear pore into cytoplasm TRANSLATION 1D mRNA is translated into a protein by a ribosome That’s how your genes (DNA) predict your appearance (proteins)! The central dogma of molecular biology outlines the flow of information as the following: A. DNA ->mRNA-> protein -> ribosome B. mRNA ->DNA -> ribosome -> protein C. DNA -> mRNA -> ribosome -> protein D. Protein -> ribosome -> mRNA -> DNA Translation is the process of: A. DNA replication B. ribosomes reading mRNA code to build a protein C. DNA copied into mRNA D. mRNA copied into DNA ORGANELLES 1E Ribosomes: read the mRNA and make proteins. Rough ER : covered in ribosomes where proteins are made. Golgi apparatus: packages proteins in vesicles which are moved to the membrane. Smooth ER: modifies and detoxifies lipids. (fats, steroids) Which cellular organelle is responsible for packaging the proteins that the cell secretes? A cytoskeleton B cell membrane C lysosome D Golgi apparatus WHICH CELLULAR ORGANELLE IS RESPONSIBLE FOR MODIFYING AND DETOXIFYING LIPIDS? A Rough ER B Mitochondria C Ribosomes D Smooth ER THE CELL MEMBRANE Cell Biology standard 1a Students know cells are enclosed within semipermeable membranes that regulate their interaction with their surroundings. CELL MEMBRANE Surrounds ALL cells! Controls what enters/leaves the cell SEMIPERMEABLE – allows some things through but not others STRUCTURE Phospholipid bilayer Polar heads “love” water (hydrophilic) Nonpolar tails “fear” water (hydrophobic) FLUID MOSAIC MODEL “Fluid mosaic model” Proteins float around like icebergs in the ocean CELL TRANSPORT Molecules can enter/leave the cell 3 ways Diffusion Carrier-Facilitated (“helped”) diffusion Active transport 1. DIFFUSION No energy required Molecules move from area of high concentration to low concentration Diffusion of water is called “osmosis” 2. CARRIER-FACILITATED DIFFUSION No energy required Molecules “helped” across by proteins from high to low concentration 3. ACTIVE TRANSPORT Energy required! ATP – the “battery” of the cell Breaking a bond in ATP releases energy Can “pump” molecules from low to high concentration building them up in the cell The cell membrane of the red blood cell will allow water, oxygen, carbon dioxide, and glucose to pass through. Because other substances are blocked from entering, this membrane is called A. perforated. B. semi-permeable. C. non-conductive. D. permeable. TRUE OR FALSE??? 1. In both diffusion and carrier-facilitated diffusion molecules move from high to low concentration. 2. The cell membrane is called the fluid mosaic model because ribosomes float around like icebergs in an ocean. 3. The type of energy needed for active transport to move molecules against the concentration gradient from low to high is ATP. The cell membrane is a phospholipid bilayer with polar heads on the inside and non polar tails on the outside. CELLULAR ENERGETICS Photosynthesis and Respiration Standards 1f and 1g PHOTOSYNTHESIS 1F Process where sunlight is converted into chemical energy stored in carbohydrates (sugar) Occurs in the Chloroplast CO2 + H2O + light C6H12O6 + O2 Carbon Dioxide + water + light Glucose + Oxygen • Has stacks of membranes called thylakoids surrounded by space called the stroma 28 REACTIONS OF PHOTOSYNTHESIS Light-dependent reactions Need light Energy from sunlight is stored in chemical bonds of ATP and NADPH O2 is released from water H2O + light ATP + NADPH +O2 (full batteries) Light-independent Reactions (Calvin Cycle) Use ATP and NADPH to make glucose from CO2 CO2 + ATP + NADPH C6H12O6 (sugar) Which of these best completes this concept map? A an animal cell B a prokaryotic cell C a virus D a plant cell Which molecule in plant cells first captures the radiant energy from sunlight? A glucose B carbon dioxide C chlorophyll D adenosine triphosphate The first stage of photosynthesis in a chloroplast is A. light-dependent. B. temperature-dependent. C. glucose-driven. D. ATP-driven. CELLULAR RESPIRATION 1G Series of reactions where carbohydrates are broken down to produce CO2 and energy (ATP) Occurs in the Cytoplasm & Mitochondria C6H12O6 + O2 Glucose CO2 + H2O + ATP energy + Oxygen Carbon Dioxide + Water + ATP energy Matrix is center of the mitochondria Cristae are folded portions of inner membrane 3 sets of reactions Glycolysis – glucose split into two pyruvate (Cytoplasm) = 2 ATP Krebs Cycle – pyruvate broken into CO2 (matrix of the mitochondria) = 2 ATP Electron TransportChain – most ATP produced (cristae of the mitochondria) = 32-34 ATP WHICH STEP OF CELLULAR RESPIRATION PRODUCES THE MOST ATP? A. Glycolysis B. Krebs Cycle C. Electron Transport Chain D. All steps produce the same amount of ATP In aerobic respiration, the Krebs cycle (citric acid cycle) takes place in A. chloroplasts. B. nuclei. C. lysosomes. D. mitochondria. A cell from heart muscle would probably have an unusually high proportion of A. lysosomes. B. mitochondria. C. mRNA. D. Golgi bodies.