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87 Cards in this Set
- Front
- Back
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Polymer |
Nucleic Acids |
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What are the monomers of nucleic acids? |
Nucleotides |
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Purines: |
Adenine and Guanine |
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Pyrimidines: |
Thymine, Cytosine, and Uracil |
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What does a nucleicacid consist of? |
Pentose Sugar + Phosphate + Nitrogenous Base |
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What bonds hold nucleotides together? |
phosphodiester bond |
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What are the 5 nitrogenous bases? |
adenine, guanine, cytosine, uracil, thymine |
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What are the basepairing rules? |
Adenine and Thymine (AT;forms 2 hydrogen bonds) Cytosine and Guanine (CG;forms 3 hydrogen bonds) |
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What is the sugar in DNA? |
Deoxyribose |
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What is the sugar in RNA? |
Ribose |
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Explain Chargaffs Rules |
Erwin Chargaff concluded that the amount of Adenine always equals the same amount of Thymine & the amount of Cytosine always equals the amount of Guanine |
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Who were the scientists that proposed the cell theory? |
Mathias Schleiden and Theodor Schwam |
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What is the cell theory? |
All living things are composed of cells Cells are the smallest unit of life Cells arise from preexisting cells |
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Explain why cells are relatively small |
due to their reliance on diffusion of substances; large cells would increase diffusion time and be very inefficient |
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Give the features that are included in all cells |
plasma membrane cytosol chromosomes ribosomes |
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Explain differences between prokaryotes and eukaryotes: |
Prokaryotes: simplest organisms DNA is present innucleoid Cell wall outside of plasma membrane Eukaryotes: Possess membrane bound organelles DNA enclosed in nucleus Cytoskeleton for cellular structure |
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What is a ribosomes function? |
Protein Synthesis |
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List all organelles in the endomembrane system: |
Endoplasmic reticulum Golgi apparatus Lysosomes |
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Functions of Endoplasmic reticulum |
Smooth ER: lipid synthesis, stores calcium ions, detoxifies Rough ER: membrane factory of the cell; produces new membrane (some cells mayproduce proteins here due to the ribosomes embedded on ER |
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Function of Golgi Apparatus |
modifies products of the ER;sorts and packages materials into vesicles (cis and trans faces) |
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Function of lysosomes(specialized vesicles) |
arise from the Golgi; contains enzymes that break down macromolecules |
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What are vesicles? |
Arise from the Golgi; serves as the transport medium in cell |
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What are mitochondria |
Energy producing organelle(ATP) |
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How many membranes do mitochondria have? |
2, double membrane (inner and outer) |
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What are the folds in the mitochondria called? |
cristae |
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What are chloroplasts |
specialized organelles inplants (and some eukaryotes) that are the sites of photosynthesis |
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what types of cells are chloroplasts found in? |
plants and some eukaryotes |
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How many membranes do chloroplasts have? |
2; double membraned |
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Explain the endosymbiotic theory: |
Nonphotosynthetic eukaryote engulfed an oxygen using prokaryote that was capable of fixing oxygen, evolved to become mitochondria. Nonphotosynthetic Eukaryote engulfed a photosynthetic prokaryote, evolved to become chloroplast. Now the initial eukaryote can fix oxygen and is photosynthetic |
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What two reasons are there to support the endosymbiotic theory |
the mitochondria and chloroplast have their DNA molecules and have double membranes |
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What is the purpose of a cytoskeleton in acell? |
to maintain cell structure |
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What are the 3 types of fibers that make up the cytoskeleton? give their functions |
Microfilaments (actin) used in muscular contractions Intermediate filaments (mainly keratin) anchors nucleus and other organelles, hold them in place Microtubules (tubulin) cell mobility |
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What is the purpose of intercellular junctions? |
way for adjacent to communicate and interact |
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Tight junctions, gap junctions, desmosomes |
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What is the current model that biologists use to refer to the plasma membrane? |
Fluid mosaic model |
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In cells, what specific molecule is the bilayer composed of? |
Phospholipids |
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What dophospholipids consist of? |
Phosphate attached to a glycerol head and two fatty acid tails |
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what type of fatty acids the bilayer composed of? |
unsaturated fatty acids |
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Give the function of cholesterol in the bilayer |
Cholesterol acts like a buffer because it resists changes in membrane fluidity due to an increase/decrease in temperature |
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In integral proteins, is the region that is embedded in the bilayer nonpolar or polar? |
nonpolar (hydrophobic) |
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Name the two types of membrane transport |
Passive transport and active transport |
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What is passive transport? |
Requires no input of energy; molecules diffuse across the membrane due to concentration gradients |
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what is diffusion? |
movement of molecules from an area of high solute concentration to an area of low solute concentration |
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What is facilitated diffusion |
movement of polar molecules across the membrane with the help of channel proteins or carrier proteins |
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What are the 3 conditions that determine movement direction in passive transport? |
1. Difference in concentration gradient 2. voltage differences across membrane 3. Gated channels (need stimulus to open) |
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What is osmosis? |
Net movement of water from an area of low solute concentration to an area of high solute concentration |
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Definition of hypertonic solution |
solution that has a high solute concentration |
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Definition of Hypotonic solution |
solution that has a low solute concentration |
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Definition of Isotonic solution |
same osmotic concentration |
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What type of solution does an animal cell prefer to be in? |
isotonic |
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What happens if an animal cell is placed in a hypertonic/hypotonic solution? |
hypertonic: shrivels up hypotonic: bursts (lyses) |
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What type of solution does a plant cell prefer to be in |
hypotonic |
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what is active transport? |
input of energy is required to move molecules up their concentration gradient (low to high concentration) |
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Give an example of active transport incells |
Sodium Potassium pump |
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What is exocytosis? |
when something exits the cell |
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What is endocytosis? |
cell intakes something |
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3 types of endocytosis |
Phagocytosis: cell takes up particulate matter Pinocytosis: "celldrinking" Receptor-mediated endocytosis: specific molecules are taken in after they bind to receptors on the membrane |
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What is energy? |
Capacity to do work |
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What is potential energy? |
Energy of position |
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What is kinetic Energy |
energy of motion |
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What is thermodynamics |
study of energy transformations |
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What are the 2 types of systems? |
Isolated system: EX: liquid in thermos bottle (no transfer of energy) Open system: energy that can be transferred between the system and the surroundings |
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Give the 2 laws of thermodynamics |
1st: energy cannot be created or destroyed, only transferred/transformed 2nd: with every energy transformation, the entropy of the universe decreases |
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Explain why organisms don't violate the 2nd law of thermodynamics |
although the entropy of the system itself is decreasing, the entropy of the system and its surroundings is always increasing |
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what is free energy? |
the amount of available energy a system has to do work |
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Spontaneous reaction |
some process or change that occurs without any outside help |
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nonspontaneous reaction |
change that will happen only if energy is supplied |
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Does a spontaneous reaction require the input of energy? |
no |
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what happens during a spontaneous change? |
system becomes more stable; processes can be harnessed to do work |
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If my G (change in free energy) is positive,then my products have more free energy than my reactants |
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If my G (change in free energy) is negative,then my products have less energy than my reactants |
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What is an exergonic reaction? |
proceeds with a net release of free energy. It is Catabolic |
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What is an endergonic reaction? |
absorbs free energy from its surroundings(nonspontaneous). Anabolic |
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What is activation energy |
the amount of energy required to initiate a chemical reaction |
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what are 2 ways in which the rate of a chemical reaction can be increased? |
1. increasing temperature 2. lowering the activation energy (via enzymes) |
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what is a catalyst? |
substance that influences chemical bonds in a way that lowers the activation energy |
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how do enzymes affect a chemical reaction? |
lowers the activation energy of a reaction |
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what is an active site? |
region on an enzyme where the substrate binds to |
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what factors can affect enzyme activity? |
pH Temperature |
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What is a competitive inhibitor? |
inhibitor that competes with the substrate for the active site |
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What is a noncompetitive inhibitor? |
inhibitor that does not compete with the substrate; binds the allosteric site and changes protein shape |
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What is feedback inhibition? |
End product of pathway binds to an allosteric site on enzyme that catalyzes first reaction in pathway Shuts down pathway so raw materials and energy are not wasted. Inition |
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What is a catabolic pathway? |
pathway where there is a breakdown of complex molecules into simpler ones |
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what is an anabolic pathway? |
process where complex molecules are made from simpler ones |
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ATP stands for |
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What is a Catalyst? |
Substance that influences chemical bonds in a way that lowers activation energy |
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If the enzyme responsible forconverting A to C was mutated and nonfunctional, what would happen? A: A levels would increase; B, C, and Dlevels would decrease. B: A and B levels would increase; Cand D levels would decrease. C: A, B and C levels would increase; Dlevels would decrease. D: A, B, C, and D levels would alldecrease. |
B: A and B levels would increase; C and D levels would decrease. |
