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Bio 141 Exam 2
| Question | Answer |
|---|---|
| What is microscopy? | -The precursor to cell biology -Using microscopes to see things that can't be seen with the naked eye |
| Who invented the telescope? | Either Zacharias Janssen or Hans Lippershay |
| Who most likely invented the telescope? | Hans Lippershay |
| What did Galileo Galilei do to the telescope? | Improve it |
| Who made the compound microscope? | Cornelius Drebbel |
| When was the compound microscope created? | The 1620s |
| What did Galileo Galilei do to the compound microscope? | He refined it |
| When was cellular biology discovered? | The 1700s |
| Who gave cells their name? | Robert Hooke |
| Where do cells get their name from? | Hooke observed plant cells and thought they reminded him of the monastery rooms |
| What book does Robert Hooke name cells in? | Micrographia |
| What is light microscopy used for? | To see bacteria |
| What was the first kind of microscopy? | Light microscopy |
| What is the largest cell in the human body? | The egg |
| What is the largest cell in the world? | The ostrich egg |
| What is the smallest microscopy we have? | Electron microscopy |
| How does transmission electron microscopy work? | It looks at tiny things and hits it with electrons |
| How does scanning electron microscopy work? | It looks at large images and bombards it with electrons |
| What are the basic features of all cells? | -Plasma membrane -Genetic material -Ribosomes |
| What is the plasma membrane made out of? | Phospholipids |
| Where is DNA stored in eukaryotes? | The nucleus |
| Where is DNA stored in prokaryotes? | The nucleoid |
| What is the function of ribosomes? | To make proteins |
| Features of prokaryotic cells | -No membrane-bound organelles -Nucleoid -Capsule |
| Bacillus has what kind of shape? | A rod shape |
| Features of eukaryotic cells | -Membrane-bound organelles -Membrane-bound nucleus -Organelles |
| Surface Area to Volume Ratio AKA Square-Cube Law | Once a cube surpasses size 6, its volume becomes much bigger than its surface area |
| Why is the Square-Cube Law important in biology? | -Explains why it's better to have many small cells vs few large cells -Cells need more surface area to perform reactions |
| Why does cell biology go against the universe? | -The universe wants things to have as little surface area as possible -Cells need more surface area to perform life-sustaining reactions |
| Why are our biggest animals underwater? | Water helps support the robust skeletons they need to support their large sizes |
| Features of an animal cell | -No cell wall -Nucleus always visible |
| Features of a plant cell | -Cell wall -Vacuole -Chloroplast |
| What is the role of the nucleus? | Store and protect DNA |
| Why is the nucleus covered in pores? | So transcription factors and RNA can go in and out for transcription or translation |
| What is the dark spot of the nucleus? | The nucleolus |
| What happens in the nucleolus | RNA synthesis |
| What is DNA wrapped around proteins called? | Histones |
| Structural winding of DNA | DNA->Histones->Chromatin->Chromosomes |
| What does it mean if a chromosome is less tightly wound? | Transcription becomes easier |
| What does it mean if a chromosome is more tightly wound? | Transcription becomes harder |
| How is wounding of chromosomes inherited? | Through epigenetics |
| What is a ribosome? | A large protein that performs translation AKA protein synthesis |
| Ribosome structure | 2 subunits that close on mRNA |
| Vesicles | AKA Endomembrane system -Transport things, has stuff inside of it |
| Endoplasmic reticulum | -Extremely close to the nucleus -Continuous with the nuclear membrane |
| 2 parts of the endoplasmic reticulum | -Rough ER -Smooth ER |
| Difference between the smooth and rough er | The rough ER has ribosomes, the smooth ER does not |
| Smooth ER | -Chemical production factory -Detoxifies drugs/poisons (the liver of the cell) -Metabolizes carbs -Synthesizes lipids |
| Rough ER | -Membrane factory -Creates vesicles out of smooth ER's lipids -Covered in ribosomes that secrete glycoproteins |
| Golgi Apparatus | -Modifies the ER products -Sorts and packages the materials from the ER into transport vesicles -Creates some macromolecules |
| Lysosomes | -Digestive and excretion system of the cell -Hydrolyzes proteins, fats, polysaccharides, and nucleic acids |
| Autophagy | -Self-eating -Recycles old pieces of cells that don't work anymore -Digests and releases it back into the cell so it can use those pieces again |
| Vacuoles | -Storage -Central vacuole holds water in plant cells -Basically a large vesicle |
| Mitochondria | -Cellular respiration and generates ATP -Cristae folds allow for more respiration |
| Chloroplasts | -Photosynthesis -Thylakoid stacks -Only in plants |
| Peroxisomes | -Mostly in plant cells -Full of enzymes -Breaks down fatty acids so they can be used for respiration and creation of membranes -Converts H2O2 to H2O and O2 -Involved in photorespiration |
| Cytoskeleton | -Provides structure -A transport highway in the cell |
| 3 components of the cytoskeleton | -Microtubules -Microfilaments -Intermediate filaments |
| Microtubules | -Thickest part of the cytoskeleton -Provide structure -Pulls chromosomes apart in metaphase -Grow out from centrosomes -Make up cilia and flagella |
| How does cilia move? | One direction |
| How does flagella move? | With the current |
| Dynein | -Motor protein that anchors microtubules using disulfide bridges -When phosphorylated, it bends -When dephosphorylated, it straightens -Causes cilia and flagella to move the cell |
| Microfilaments | -Twisted double chains of actin -Present in muscles -ATP helps it flex |
| Intermediate filaments | Support cell shapes and hold organelles in place |
| Cell wall | -Unique to plant cells -Porous -3 layers (primary, secondary, and plectin) |
| Extracellular matrix | -Support, adhesion, movement, regulation -Made of glycoproteins (collagen, proteoglycans, fibronectin) |
| How do cells stick together and do the same thing? | Structural junctions and gaps |
| Tight junctions | Nearby cells are smashed together, preventing leakage of fluids |
| Desmosomes | Cellular velcro, fastens cells together in sheets |
| Gap junctions | Gaps in the cell membrane that provide channels between adjacent animal cells |
| Plasmodesmata | Gaps in cell wall that provides channels between adjacent plant cells |
| What is selective permeability? | Some things get in the cell, some things can't |
| Davson and Danielli | -Proposed the sandwich model of the plasma membrane (1935) |
| What is the sandwich model? | -Inside of sandwich is phospholipids tails -Outside of sandwich is very smooth, thick layer of proteins covering the phospholipid heads |
| Why is the sandwich model incorrect? | Proteins have positive and negative charges, so they would never form a uniform protein layer |
| Seymore Singer and Garth Nicolson | Proposed the fluid mosaic model of the plasma membrane (1972) |
| Fluid mosaic model | -Fluid = it moves -Mosaic = made up of many things (carbs, proteins, etc.) -Phospholipids can move sideways or across the membrane -Can become more fluid with heat |
| How do we know the fluid mosaic model is correct? | -Cells were dumped in a freezer -Freeze fracturing caused the bilayer to be separated -Proteins were on one side with corresponding hole on the other side |
| 3 types of membrane proteins | -Peripheral -Integral -Transmembrane |
| Cellular fractionation | Separating cellular components with sound waves while preserving their individual functions |
| Peripheral proteins | Proteins only on the edge of the cell |
| Integral proteins | Proteins that are within the membrane |
| Transmembrane proteins | Proteins that go completely across the membrane |
| Frye and Edidin | -Combined a mouse cell and a human cell -Created a hybrid cell -Proteins on the membrane were mixed after 1 hour |
| What keeps the membrane fluid? | -Kinks in hydrocarbon tails -Cholesterol fluidity |
| Major functions of membrane proteins | -Transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to cytoskeleton and extracellular membrane |
| Cell-cell recognition | -Helps your body to identify existing viruses -Also tells your cells if they know each other -Use spike proteins on cells to determine recognition |
| What can pass through the cellular membrane? | -Small nonpolar and polar molecules -Gases, hydrophobic molecules |
| What cannot pass through the cellular membrane? | -Large polar molecules -Charged molecules (ions, amino acids) |
| How do large polar molecules and charged molecules pass through the membrane? | Active transport, passive transport, and ion-gated channels |
| Facilitated diffusion | The protein passively diffuses something down a concentration gradient |
| Passive transport: Diffusion | Movement of solute down the concentration gradient without the use of a protein |
| Osmosis | Movement of the solvent (water) down the concentration gradient |
| Isonic solution | -Concentration of salt is the same inside and outside a cell -Ideal situation |
| Hypotonic solution | -Less solute on outside of cell, more on inside -Water rushes in to dilute the inside of the cell -The cell bursts (lysed) |
| Hypertonic solution | -More solute on outside of cell than inside -Water rushes out, cell shrivels and dies -AKA as plasmolyzed in plant cell |
| Osmoregulation | -The ability to moderate water in a cell -Done by a contractile vacuole in bacteria cells |
| Passive transport | The transportation of things across a membrane with the concentration gradient |
| Active transport | -Transport that goes across a membrane and against the concentration gradient |
| How does active transport work? | -ATP becomes ADP+ and phosphate, energy comes from this broken bond -The phosphate attaches to a transport protein, signals it to change shape and transport something -AKA a phosphorylated intermediary |
| What is a phosphorylated intermediary? | When a phosphate bonds to a protein and causes it to change shape |
| What is the proton pump? | -Transports H+ ions -ATP needed to pump H+ out of the cell -H+ attaches to sucrose-H+ cotransporter and charges the protein to move sucrose into the cell |
| Why is coupled transport good? | -It uses less ATP to carry more things across the membrane -Getting more bang for the cell's buck |
| What is bulk transport? | Vesicles moving things across a membrane |
| Phagocytosis | -Cell eating -Vesicle breaks off cell membrane and encapsulates large food particle |
| Pinocytosis | -Cell drinking -Vesicle breaks off membrane and grabs extracellular fluid, brings it inside the cell |
| Receptor-mediated endocytosis | -Receptors on the cell membrane pick up the matching ligands -When the receptors are full, the membrane forms around it in a bubble -Bubble is covered in coat proteins -The bubble gets transported to a specific spot in the cell based on coat proteins |
| Metabolism | The ability to use energy and the efficiency at which something can use it |
| Cells are _______ factories that extract energy to do work | chemical |
| Anabolism | The synthesis of complex molecules |
| Catabolic pathways | Release energy by breaking complex molecules Ex. cell respiration |
| Anabolic pathways | Consume energy to build complex molecules Ex. protein synthesis |
| What is energy? | -The capacity to cause change -Exists in many forms, some of which can perform work |
| Kinetic energy | The energy of movement |
| Thermal energy | Energy of heat |
| Potential energy | Stored energy (energy of position, energy in chemical bonds) |
| Closed system | -Do not exchange energy with the external environment -Don't typically exist in nature |
| Open system | -Exchange energy with the environment -Energy can flow in and out -Ex. our bodies |
| 1st Law of Thermodynamics | -Energy can't be created or destroyed -It can only be transferred and transformed -Energy is conserved |
| 2nd Law of Thermodynamics | -There is no such thing as a perfect system -Some energy is always lost, usually as heat -Happens during transferring or transforming -Entropy is always increasing over time |
| What is entropy? | Randomness, chaos |
| Processes that _________ entropy are energetically favorable | Increase |
| Processes that _________ energy are often spontaneous | Release |
| One example of entropy laws being broken | The golden ratio (order is favored over disorder) |
| What is free energy? | -Energy that can do work when temperature and pressure are uniform -Determines whether a reaction will occur spontaneously or not |
| Gibbs Free Energy equation | ΔG=ΔH-TΔS |
| What is the T in the Gibbs Free energy equation? | Temperature in Kelvin |
| What is the ΔG? | G2-G1 |
| What is ΔS in the Gibbs Free energy equation? | Change in entropy |
| ΔG is positive when energy was put into a system, and the reaction is ________ | Not spontaneous |
| ΔG is negative when energy is released from the system, and the reaction is ________ | Spontaneous |
| What is ΔH in the Gibbs Free energy equation? | Enthalpy AKA total energy |
| Exergonic reaction | -Energy released -Spontaneous -Products have less energy than reactants -Exothermic |
| Endergonic reaction | -Energy required -Nonspontaneous -Products have more energy than reactants -Endothermic |
| What does ATP stand for? | Adenosine triphosphate |
| What does ATP do? | -Powers endergonic reactions |
| How does ATP work? | -When a phosphate group is broken, energy is released and can be used for endergonic reactions -When a phosphate is added back on, ATP regains its energy |
| How is ATP renewable? | -It can be phosphorylated and dephosphorylated |
| What do enzymes do? | -Lower the activation energy needed for a reaction -This either enables a reaction to happen or speeds it up |
| What is an enzyme? | A biological catalyst |
| What is a substrate? | The reactant(s) and enzyme acts on |
| Enzyme-substrate complex | The structure formed when the substrate binds to the enzyme's active site |
| Lock and key model | -Every enzyme and substrate are perfectly shaped to fit together -Incorrect |
| Induced fit model | -Enzymes have to change shape to bind to the substrate -Enzyme goes back to original shape after the reaction is over -Correct |
| Enzymes function best at _________ levels (pH, temperature) | Optimal |
| What do cofactors do? | They help the enzyme do its job by binding to an active site to change so it can fit the substrate |
| What is an amphipathic molecule? | A molecule with both polar and nonpolar parts Ex. phospholipids |
| Competitive Inhibition | An inhibitor binds to an active site, blocking the substrate out and stopping a reaction |
| Noncompetitive Inhibition | An inhibitor binds somewhere other than the active site and changes the shape of the enzyme, stopping the reaction |
| Allosteric activation | -A regulatory molecule binds to a protein somewhere other than the active site -Allows the active site to become available to the substrates |
| Allosteric inhibition | -A regulatory molecule binds to a protein somewhere other than the active site -The active site becomes unavailable to the substrates |
| Negative feedback inhibition | More product inhibits a reaction |
| Positive feedback inhibition | More product keeps the reaction going |
| Why is cell communication important? | For cells to function in tissues/organs, they need to be doing the same thing |
| How do most signals start? | With an external stimulus |
| Example of responding to external stimuli | -Yeast reproduces sexually and asexually -Alpha yeast can send signals to beta yeast -They combine to form a joint alpha and beta yeast cell because of cellular signaling |
| What are the three types of signaling? | -Direct signaling -Local signaling -Long-distance signaling |
| Direct signaling | -Signaling to cells that are touching -Ex. Gap junctions in animal cells and plasmodesmata in plant cells -The cells freely exchange cytoplasm and signals to the cells attached to it |
| Local signaling | -A chemical is released -The cells nearby react to the chemical -Ex. synaptic signaling between neurotransmitters and synapses -Ex. paracrine signaling between hormones and nearby target cells |
| Long-distance signaling | Signaling between cells that are not close to each other -Ex. Endocrine system: hormone is released into the bloodstream and affects the entire body |
| Who discovered the Signal Transduction Pathway? | Earl Sutherland Jr. |
| What else did Earl Sutherland Jr. discover? | -cAMP -How epinephrine works |
| What are the three stages of cell signaling | -Reception -Transduction -Response |
| What is reception? | -A ligand from outside the cell binds to a receptor inside the cell |
| What is transduction? | -The signal from the receptor gets passed on like a relay race in the signal transduction pathway |
| What is response? | A cellular response, could be many different things |
| What are the three main receptors in the plasma membrane? | -G-protein coupled receptors (GPCR) -Receptor Tyrosine Kinase (RTK) -Ligand-gated ion channels |
| G-protein coupled receptors | -Ligand goes in the receptor -G-protein attaches to the receptor and activates to GTP -G-protein and GTP go to an enzyme and activate it -The enzyme creates the cellular response |
| How are G-protein coupled receptors good at sustaining reactions? | -GTP becomes GDP and vice versa, always renewable -G-protein never runs out, can always shuttle the GTP/GDP back and forth between receptor and enzyme as long as the ligand is present |
| Receptor Tyrosine Kinase | -Ligand binds to a receptor -2 receptors combine to form a dimer -Each dimer has six tyrosines -Tyrosines can phosphorylate and bond to enzymes -Enzymes cause cellular response |
| Why are Receptor Tyrosine Kinases efficient? | They can cause 6 responses at once |
| Ligand-gated ion channels | -Ligand binds to a receptor/gate -The gate opens and lets ions flow across the plasma membrane -Flow of ions cause cellular response -This is how neurotransmitters work |
| Why are ligand-gated ion channels very fast? | When the gate opens, ions can flow very quickly all at once |
| Signal Transduction Pathway | -Protein kinase transfers P from ATP to proteins -Protein phosphatase removes the P -Signal->Reception->Activate kinase 1->phosphorylation->Activate kinase 2->phosphorylation->Activate kinase 3->Phosphorylation->Activates protein->Cellular response |
| What are second messengers? | -Things that bridge the gap between reception and transduction |
| Examples of second messengers | -cAMP -Calcium |
| How is cAMP a second messenger? | Enzymes release cAMP which reaches the target and causes phosphorylation |
| How is calcium a second messenger? | -When calcium flows across a membrane, it carries a positive charge -This positive charge activates the response |
| How does a protein kinase cascade work? | The kinases continuously phosphorylate each other until the desired protein is activated |
| What is cytoplasmic streaming? | The direct flow between cells using cytoplasm and its chemicals |
Created by:
jordanleigh