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Biology Exam 2

Chapter 4,5,6

QuestionAnswer
What are the 3 domains of living things? Bacteria, Archaea, Eukarya.
What size is a virus? 0.2 microns.
What are the two main components of a virus? Capsid - composed of proteins. Nucleic Acid Core - DNA or RNA.
What cells are Prokaryotes? Bacteria and Archaea.
What cells are Eukaryotes? Eukarya.
What is a cell? Smallest unit of life, plasma membrane, cytoplasm and DNA.
What is the smallest unit of life? Cell.
What contains a plasma membrane, cytoplasm and DNA? Cell.
How are new cells created? Division of pre-existing cells.
How does one organism produce different types of cells? Proteome- the entire set of proteins expressed by a genome, this determines cell’s structure and function.
What does volume determine in a cell? The amount of chemical activity in a cell per unit time.
What does surface area determine in a cell? The amount of substances that can pass the cell boundary per unit time.
Why is the surface area to volume ratio important? The physical relationship between increasing volume and surface area constrains cell size and shape.
How is surface area ratio determined. More surface are and less volume = higher surface area ratio.
What are the types of cells? Prokaryote and Eukaryote.
What has no nucleus and is not a membrane bound organelle? Prokaryote.
What has a defined nucleus and is a membrane bound organelle? Eukaryote.
What do all prokaryotes have? Plasma Membrane Nucleoid Cytoplasm Ribosomes
What is found in MOST but NOT all prokaryotes? Cell Wall Flagellum Plasmid
What are the basic shapes of prokaryotes? Bacillus (Rods) Coccus (spheres) Spirals
Explain Binary Fission. When a bacterial cell replicates its genome and divides in half. Asexual Reproduction
What are the three types of Genetic Recombination in bacteria? Conjugation, Transformation, Transduction.
What is Conjugation? Male cell passes DNA to female cell through a sex pilus.
What is Transformation? Bacterium takes up DNA from environment released by dead bacteria.
What is Transduction? Viruses carry bacterial DNA from cell to cell.
What do antibiotics do in the cell? Inhibit protein synthesis by bacteria and inhibit cell wall biosynthesis.
Are Archaea closely related to Bacteria or Eukaryotes? Eukaryotes, based on nucleic acid similarities.
What are Archaea? Thermoacidophiles, Methanogens, Halophiles.
What do Eukaryote cells have compared to a prokaryote? Nucleus, Cytoskeleton, Compartmentalization, Membrane enclosed organelles.
Which is larger, Prokaryote or Eukaryote? Eukaryote.
What is the difference between plant and animal cells? Plant cells have a cell wall, central vacuole, and chloroplast.
What do animal cells not have? Cell walls, central vacuole, and a chloroplast.
Animal and plant cells both have what? Plasma Membrane.
What are the four parts in the Eukaryote system? Cytosol, Nucleus, Endomembrane system, and Semiautonomous Organelles.
What is the Cytosol? Central coordinating region for many metabolic activities. Region of eukaryotic cell outside the organelles but inside the plasma membrane.
Types of Cytoskeleton? Actin, Intermediate Filaments, Microtubules.
What is the function of the Cytoskeleton? Cell Shape, Internal Organization, Intracellular Transport, Movement.
Importance of the Nucleus? Contains most of the DNA which codes for protein. Assembles Ribosomes in the Nucleolus. Has the Nuclear Membrane that is double layered and has the Endomembrane System.
Where are Ribosomes located? Assembled in Nucleolus, free in Cytoplasm, in the Mitochondria and Chloroplast, bound to the ER.
Where does protein synthesis occur? Ribosomes.
What does the Endomembrane system do? The system makes and modifies lipids and proteins; it also recycles and disposes of molecules and particles.
What does the Endomembrane system consist of? Nuclear Membrane, Golgi Apparatus, and Plasma Membrane, Vesicles/Vacuoles.
What are the three Vesicles? Lysosomes, Central Vacuole, Peroxisomes.
What is the ER of the Endomembrane System? Rough and Smooth.
What is the Endoplasmic Reticulum? Network of membranes, ER membrane encloses lumen.
What is the difference between rough and smooth ER? Rough ER is studded with Ribosomes. Smooth ER lacks Ribosomes.
What does Rough ER do? Sorts and folds proteins, inserts proteins into ER membrane and Glycosylation.
What does Smooth ER do? Continuous with rough ER, functions depend on cell type, and Synthesis and modification of lipids.
What does the Golgi Apparatus do? Stack of saccules, has three overlapping functions for proteins- sorting, processing, and secretion.
What does the Lysosome control? Specialized vesicles with digestive enzymes, Phagocytosis (digesting food), Autophagy (breaking down damaged organelle), Destroy invaders, Apoptosis.
What does the Vacuole do? Central vacuoles in plants, Contractile vacuoles in protists, Phagocytic vacuoles in white blood cells, Store wastes and toxic compounds, Store anthocyanins (pigments).
What do Peroxisomes do? Contain specific digestive enzymes Including catalase, Break down toxic hydrogen peroxide, Cells that break down large amounts of lipids- liver cells and germinating seeds.
What is he protein process in Eukaryote cells? Nucleus- DNA codes for proteins. Ribosomes- site of protein synthesis. Rough ER- folding of proteins. Golgi Apparatus- Sorting of proteins. Vesicles- Transporting of proteins.
What are the Semiautonomous organelles? Can grow and divide to reproduce themselves, but they are not completely autonomous because they depend on other parts of the cell for their internal components. Mitochondria and Chloroplasts.
What are Mitochondria? Make ATP, outer and inner membrane, intermembrane space. mitochondrial matrix, contain their own DNA, divide by binary fission.
What are Chloroplasts? Plastids, plants and some protists, Chloroplasts are one type of plastid, photosynthesis, in nearly all plants and algae, contain own DNA, divide by binary fission.
What are the functions of the cell membrane? Physiological roles, Boundary, Regulates movement.
What is the cell membrane composed of? Lipids, Proteins, and Carbohydrates.
Types of Lipids? Phospholipids and Cholesterol.
Phospholipids are what? Amphipathic, Hydrophilic Heads, Hydrophobic Fatty Acids.
Cholesterols is? Only in animals and stabilization.
In plants cholesterol is what? Phytosterols.
Types of proteins? Integral (intrinsic) proteins. Peripheral (extrinsic) proteins.
What is the difference between Integral and Peripheral proteins? Integral is transmembrane or lipid-anchored proteins. Peripheral is bound to integral or bound to polar head.
Membranes are what? Semifluid.
Semifluid means what? Most lipids can rotate freely around their long axes and move laterally within the membrane leaflet
Flipflopping of lipids does not occur spontaneously. True.
What affects fluidity? Length of fatty acid tails- Shorter tails are more fluid. Double bonds in the acid tails- Increasing unsaturated fatty acid content, more fluid. Presence of Cholesterol- Cholesterol stabilizes membranes.
What causes a lipid raft? Certain lipids associating strongly with each other.
What do lipid rafts do? Rafts float together as a unit and they function in cell signaling.
Why is composition of lipid raft is different than rest of membrane? High concentration of cholesterol. Unique set of membrane proteins.
Why are 10-70% of proteins restricted? Integral proteins may be bound to cytoskeleton. Proteins may be attached to the extracellular matrix.
What are the membrane carbohydrates? Glycolipid and Glycoprotein.
What do the membrane carbohydrates do? Recognize signals.
What is Synthesis of Membrane Components in Eukaryotic Cells? Synthesis of lipids which then add carbohydrates then add Transmembrane Proteins.
How does synthesis of lipids work? In eukaryotes, the cytosol and endomembrane system work together to synthesize lipids. Fatty acid building blocks are made via enzymes in cytosol or taken into cells from food. Process occurs at cytosolic leaflet of the smooth ER.
What happens when membrane synthesis adds carbohydrates? Protein glycosylation through N-linked and O-linked.
What is N-linked? Membrane proteins are transported to the cell surface.
What is O-linked? Proteoglycans secreted from cells and part of extracellular matrix.
What happens when membrane synthesis adds transmembrane proteins? Transmembrane proteins are redirected to the ER membrane first, from there membrane proteins can be transferred via vesicles.
What is the exception for transmembrane proteins in membrane synthesis? Proteins designated for semiautonomous organelles.
Membrane transport is what? A selectively permeable plasma membrane.
What does the structure of the membrane transport do? Essential molecules enter, metabolic intermediates remain, waste products exit.
What is passive transport? No energy input, down concentration gradient. Passive and Facilitated Diffusion.
What is active transport? Energy input, against concentration gradient.
What is diffusion? Net movement of molecules or ions from a region where they are more concentrated to a region where they are less concentrated.
What factors affect Diffusion rates? Size- smaller faster Temp- hotter faster Steepness of Gradient- steeper faster Charge- more complex Pressure- higher faster
What are the types of gradients for a cell? Transmembrane Gradient. Ion electrochemical gradient.
Internal gradient is different than the external gradient in cells. True.
What is Osmosis? Diffusion of water across a selectively permeable membrane.
How does diffusion work in Osmosis? Water diffuses from a region with lower solute concentration toward a region with higher solute concentration.
What is Hypertonic? More solute, less water.
What is Hypotonic? Less solute, more water.
What is Isotonic? Same amount of solute on either side.
How does water flow is Osmosis? Water flows from Hypo to Hyper.
Osmosis in animal cells must do what? Must balance with Crenation and Lysis.
Osmosis in plant cells must have what? Turgor Pressure and Plasmolysis.
Transport proteins are what? Transmembrane proteins that provide a passageway.
What are the two classes for manner of movement? Channel and Transporters. Both can be active or passive.
What are Channels? Open Passageway, Passive, Faster.
What are Transporters? Conformational Change, Organic Molecules, Passive or Active, Slower.
What are the types of Transporters? Uniporter- Single solute in one direction. Symporter- Two solutes in same direction. Antiporter- Two solutes in opposite directions.
What is Primary Active Transport? Uses a pump, ATP used directly.
What is Secondary Active Transport? Uses pre-existing gradient to drive transport, uses ATP indirectly.
How are larger molecules transported? Endocytosis and Exocytosis.
What is Endocytosis? Phagocytosis/Phagocytosis . Receptor-mediated endocytosis.
What is Exocytosis? Process by which materials packaged in vesicles are secreted from the cell.
What is Energy? The ability to do work.
What are forms of Energy? Light to Chemical Electric to Thermal Chemical to Mechanical
What are the states of Energy? Kinetic and Potential
What is Catabolic Energy? A reaction that breaks down complex molecules to make their energy available to do work.
What is Anabolic Energy? A reaction that requires energy to assemble simple substances into more complex molecules.
What is Thermodynamics? The study of energy flow during chemical and physical reactions.
What is the first law of Thermodynamics? Energy can be transferred but it can not be created or destroyed.
What is the second law of Thermodynamics? A total disorder/entropy of the system and its surroundings alwasy increase.
How is the second law of Thermodynamics restated? Each time energy is converted or transferred it becomes less useful.
In any system what is the equation for energy? Total energy = usable energy + unusable energy OR Enthalpy(H) = Free Energy(G) + Entropy(S) OR H=G+TS T=Absolute Temp OR Usable Energy= G=H-TS
What is Free Energy? The energy available to do work in biological systems. Can be used to predict direction of reaction.
What is the equation for Free Energy? Change in Free Energy = ^G ^G=G (final state)-G(initial state)
How is the change in Free Energy measured? At constant temperature it can be measured precisely in Joules or Calories. ^G=^H-T^S
What if ^G is Positive? Anabolic reaction, free energy is required.
What is ^G is Negative? Catabolic reaction, free energy is released.
What is Exergonic? Product has less free energy than the reactant, spontaneous.
What is Endergonic? Product has more free energy than the reactant, requires energy input.
What is ATP? Capture, Storage, and Transfer of Energy.
What happens to free energy when released from an exergonic reaction? ATP captures it, then can release it to drive endergonic reactions.
What makes us hot? Chemical reactions turn to mechanical reactions, a release of energy is given off, from a exergonic reaction. Then heat is give off.
Biochemical reactions that are to slow are what? Spontaneous.
Catalyst in a biochemical reaction will do what? Speed up the rate of reaction, but is not changed by the reaction.
What is the most common catalyst? Enzymes.
What is an Enzyme? Protein.
What is a Ribozyme? RNA.
The direction of a reaction can be predicted if ^G is known, but not the rate of reaction. True.
What is activation energy? The amount of initial energy input needed to start a reaction, Molecules can then get close enough for bond rearrangement, Now they can achieve transition state where bonds are stretched.
What is transition state? An intermediate and unstable arrangement of atoms and bonds that both the reactants and products assume.
How can you overcome activation energy? Heat and Enzymes.
What is the reactant that an enzyme will bind to? Substrate.
What does the enzyme and substrate form? Enzyme- Substrate Complex.
What is the active site? The region on the enzyme where the substrate binds.
Structures determine function? True.
Most enzymes are larger than their substrate. True.
The active site is a small region of the whole protein. True.
What is the specificity that depends on a precise interlock? Lock and Key.
What is induced fit? Change in Enzyme shape caused by substrate binding.
What are the functions for the rest of the enzyme? Framework for positioning of amino acids of active site. Participate in small changes that allowed induced fit.
Why do reactions that might take years to happen can occur in a fraction of a second? Enzymes can have a profound effect on reaction rates.
What happens at the active site? Enzymes and substrates interact by breaking old bonds and forming new ones.
What is Saturation in Enzyme reactions? Plateau where nearly all active sites are occupied by substrates.
Velocity of a reaction near its maximal rate is what? Vmax.
Substrate concentration at which velocity is half maximal value is what? Km.
Km is also called what? Michaelis Constant.
High Km enzymes need a higher or lower substrate concentration? Higher.
Km is inversely related to the affinity between enzyme and substrate. True.
What factors affect Enzyme function? Prosthetic Groups, Cofactor, Coenzyme.
What is a prosthetic group? Small molecules permanently attached.
What is a Cofactor? Usually inorganic ion that temporarily binds.
What is a Coenzyme? Organic molecule that participates in reaction but left unchanged afterward.
What other factors could affect Enzyme functions? Temperature, pH, and salt concentration.
What is activation in regulation of enzyme activity? A molecule binds to the enzyme to activate it (turn it on).
What is inhibition in regulation of enzyme activity? A molecule binds to the enzyme to inactivate it or slow it down.
What are the types of Regulation in enzymes? Competitive and Noncompetitive/ Allosteric
Competitive regulation is what? Molecule that will activate or inactivate the enzyme binds directly to the active site of the enzyme.
Allosteric or noncompetitive regulation is what? Molecule that will activate or inactivate the enzyme binds to a site other than the active site of the enzyme.
Chemical reactions occur in metabolic pathways and Each step is coordinated by a specific enzyme. True.
Catabolic pathways..... Result in breakdown and are exergonic. Recycle organic building blocks. Produce energy intermediates. Redox reactions are important in the metabolism of small organic molecules.
Anabolic pathways..... Promote synthesis and are endergonic.
How is metabolism organized? Sequences of enzyme-catalyzed chemical reactions called pathways. In these sequences, the product of one reaction is the substrate for the next.
What are the redox reactions? Oxidation, Reduction, Redox reaction.
What is Oxidation? Removal of electrons.
What is reduction? Addition of electrons.
What is redox reactions? Electron removed from one molecule is added to another.
What is NAD? Coenzyme is an essential electron carrier in cellular redox reactions, exists in an oxidized form, and can be reduced.
Reduction required what? Input of energy.
Oxidation requires is what? Exergonic.
What are the regulations of metabolic pathways? Gene Regulation, Cellular Regulation, Biochemical Regulation- feedback inhibition.
What does Gene Regulation do? Turns genes on or off.
What does Cellular Regulation do? Cell signaling pathways, respond to environment, hormone epinephrine activates enzymes that increase carbohydrate breakdown. Compartmentalization, isolate pathways in membrane-bound organelles.
What is Feedback Inhibition? Product of pathway inhibits early steps to prevent overaccumulation of product. This is a type of biochemical regulation.
Created by: Jacque_H36