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144 Cards in this Set
- Front
- Back
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Prokaryotic cells divide by:
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Binary Fission
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Most eukaryotes have between __________ chromosomes in their body cells.
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10 - 50
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During which phase of the cell cycle is DNA synthesized
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S
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Proteins with positive charges that are wrapped areound DNA within chromosomes are:
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Histones
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The G1, S, and G2 phases of the cell cycle are collectively known as:
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Interphase
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Replicate copies if each chromosome are called _____ and are joined at the ______
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sister chromotids
centromere |
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The proper sequence, beginning to end, for the stages of mitosis is
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Prophase
metaphase anaphase telophase |
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The eukaryotic cell cycle is controlled at several points; which of these is not a control point?
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Cell growth is not assessed at the S checkpoint
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What causes cancer cells in cells?
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Damage to genes failing to stop cell division
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Mutations disabling key elements of the G1 checkpoint are associated with many cancers
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True
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What cell cycle regulatory protein is the tumor-supressor protein?
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P53
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Fertilization results in:
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a zygote
a diploid cell a cell with a new genetic combination |
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The diploid number of chromosomes in humans 46. The haploid number is:
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23
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During which stage of meiosis does crossing over occur?
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Prophase 1
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Duplication of DNA occurs
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during interphase
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When does separation of homologous chromosomes occur?
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anaphase 1
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Genetic recombination is possible because of ________ during or after meiosis.
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independent assortment
crossing over fertilization with a nonrelated gamete |
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After meiosis, the gamete join with another gamete in all eukaryotic organisms.
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false
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Which of these is not a unique feature of meiosis?
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diploid daughter cells are not unique
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The arrangement of the chromosomes in metaphase 1 of meosis is not important as long as homologues pair.
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True
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The life cycle of a cell is known as the
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Cell Cycle
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Pairs of chromosomes that have the same size, shape, and function are
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Homologous
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During mitosis, chromosomes are lined up at the equator of the cell during this phase
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Metaphase
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Cytoplasm is cleaved in two during the ______ phase of the cell's life cycle.
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C phase
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The daughter chromatids are separated and pulled to their respective poles during ____ of mitosis.
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Anaphase
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Objects that are not actively moving but have the capacity to do so are said to possess:
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potential energy
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Reactions that tend to go on their own, releasing energy, are called:
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exergonic
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Enzymes are catalysts because they operate to
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lower activation energy
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The site on the surface of an enzyme where the reactant binds to the enzyme is called the:
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binding site
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Which of the following activities does not require cellular energy?
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movement of water across the cell membrane
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ATP is composed of sugar, the organic base adenine, and:
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three phosphate groups
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In reference to enzyme activities, repressors _____ the active site, while activators _____ it.
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DISRUPT
RESTORE |
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The site on the enzyme surface where the reactant fits is referred to as the:
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active site
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Objects that are moving are said to possess
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kinetic energy
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The making and breaking of chemical bonds is called
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chemical reactions
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The First Law of Thermodynamics states
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that energy can be changed from one form to another, but cannot be created or destroyed
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The extra energy required to destabilize existing chemical bonds and to initiate a chemical reaction is called
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activation energy
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When a cytoplasmic vesicle fuses with the plasma membrane, expelling its contents outside the cell, the process is know as
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exocytosis
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Choose the membrane molecule responsible for aiding passage of polar molecules into and out of the cell.
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transmembrane proteins
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When molecules move through a cell membrane from an area of greater concentration to an area lesser concentration by way of a channel protein, it is called
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facilitated diffusion
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When plant cells are placed in a salt solution, they don't shrink up in the same manner as do animal cells. This is due to the fact that plants have
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Cell Walls
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Which of the following processes requires - BOTH a channel protein AND energy?
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Active transport
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The capacity to work and cause change
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Energy
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Work is accomplished when and object is moved against an opposing force, such as friction
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Part of energy
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Kinetic Energy
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The energy of motion
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Potential Energy
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Energy that an object possesses as a result of its location
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Kinetic energy performs works by trasferring motion to other matter
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heat or thermal is kinetic energy associated with the random movement of atoms
ex.water moving through a turbine generates electricity |
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Example of potential energy is water held behind a dam
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potential
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Chemical Energy
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Potential energy because of its energy available for release in a chemical reaction
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energy transformations within matter are studied by individuals in the field of
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thermodynamics
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Biologists study thermodynamics because
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an organism exchanges both energy and matter with its surroundings
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1st law of thermodynamics
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Energy is constant
neither created of destroyed |
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2nd law od thermodynamics
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Energy conversion increase the disorder of the universe
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ENTROPY
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The measure of disorder or randomness
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CHEMICAL REACTION
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making and breaking of chemical bonds
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REACTANTS
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the molecules you start with
AKA substrates |
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PRODUCTS
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the molecules you end up with
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Types of reactions
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exergonic reaction
endergonic reaction |
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EXERGONIC REACTION
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Chemical reaction that releases energy. Think exit
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EXERGONIC REACTION
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releases the energy in covalent bonds of the reactants
burning wood releases energy in glucose, producing heat, light, carbon dioxide, and water |
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cellular respiration
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releases energy and heat and produces products but it is able to use the release energy to perfom work
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ENDERGONIC REACTION
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requires an input of energy and yields products rich in potential energy
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ENDERGONIC REACTION
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the reactants contain little energy in the beginning but the energy is absorbed from the surroundings and stored in covalent bonds of the products
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ENDERGONIC REACTION
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photsynthesis makes energy-rich sugar molecules using energy in sunlight
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The cell does 3 types of cellular work
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chemical work
transport work mechanical work |
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cellular work - chemical
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driving energonic reactions
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cellular work - transport
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pumping sunstances across membranes
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cellular work - mechanical
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beating of cilia
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to accomplish work a cell must manage its energy resources
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energy coupling
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energy coupling
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the use of exergonic processes to drive and endergonic one
exer drives ender |
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Cells have thousands of
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exergonic and endergonic reactions
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Total of all these reactions equal
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metabolism
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2 types of Metabolism
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Anabolic put molecules together-uses energy (endergonic)
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2 types of metabolism
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Catabolic breaks molecules apart-releases energy (exergonic)
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Energy must be available to break bonds and form new ones.
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EA energy of activation
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Used to initiate a chemical reaction or chemical nudge
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EA energy of activation
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Cell use______to drive (speed up) biogical reactions
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catalysis
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Catalysis is accomplished by ______ which are proteins that function as biological catalysis
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enzymes
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enzymes speed the rate of the biological reaction by ______ and they are not used up in the process
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lowering the EA
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In a catalysis each enzyme has a particular target molecule called the
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substrate or reactant
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Enzymes have unique
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three-dimensional shapes
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Shape is critical
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to a enzymes role as biological catalysis
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where the enzyme interacts with the enzyme's substrate
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active site
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The substrate's chemistry is altered to form the
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product of the enzyme's reaction
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The site on the reactant (substrate) that binds to the enzyme is called the
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binding site
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High temperatures
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Denatures human enzymes
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Enzymes require
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pH around neutrality for best results
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Human enzymes function best at temperature
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37 degrees C or body temp
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Some enzymes require
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non-protein helpers
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Non-protein factors
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cofactors
coenzymes |
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cofactors
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inorganic, such as zinc iron copper (minerals)
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coenzymes
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organic molecule and are often vitamins
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Many coenzymes
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are necessary for cellular respiration. Eat fruits and veggies
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Enzymes (proteins)
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have a precise shape needed to function properly
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Cells can regulate this shape by sending
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signal molecules
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2 types of signal molecules
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repressor
activators |
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Repressor
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act to inhibit enzymes activity
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Activators
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signals molecule that is necessary to allow the enzymes to work
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Signal Molecules binds to enzymes at
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allosteric sites
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Inhibitors
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chemicals that inhibit an enzyme's activity
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One group inhibits because they compete for the enzyme's active site and thus block substrates from entering the active site
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competitive inhibitors
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Non competitive inhibitors
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Other inhibitors do not act directly with the active site these bind somewhere else and change the shape of the enzyme so that substrate wil no longer fit the active site
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Feedback Inhibitors
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Ezyme inhibitors are important in regulating cell metabolism often the product of a metabolic pathway can serve as an inhibitor one enzyme inthe pathway, a mechanism
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The more product formed, the greater the inhibition, and in this way, regulation of the pathway is accomplished
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Chain of reactions continue - when an enzyme is too much cells says stop
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Tryptophan
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Body can make
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ATP
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adenosine triphosphate
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ATP
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energy curency of cells.
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ATP
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IMMEDIATE SOURCE OF ENERGY THAT POWERS MOST FORMS OF CELLULAR WORK
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ATP is composed of
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adenine (a nitrogenus base)
ribose (a five-carbon base) and 3 phosphate groups |
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Hydrolysis of ATP releases energy by transferring it third phosphate from ATP to some other molecule. ATP energizes moleculesysis
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PHOSPHORYLATION
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hydrolysis
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cells break bonds
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energy is stores in the COVALENT BONDS between phosphates
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pyrophosphate bonds
Greatest amount of energy is between the 2nd and 3rd phosphate groups |
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ATP is a renewable source of energy for the cell
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WHEN ENERGY IS RELEASED IN AN EXERGONIC REACTION, SUCH AS BREAKDOWN OF GLUCOSE, THE ENERGY IS USED IN AN ENDERGONIC REACTION TO GENERATE ATP
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PHOPHOLIPID BILAYER
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proteins embedded in the membrane serve different functions
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Channel Proteins
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form small openings for molecles to diffuse through
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Carrier Proteins
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bindind site on protein surface "grabs" certain molecules and pulls them into the cell
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Receptor Proteins
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molecule triggers that set off cell responses (such as release of hormones of opening of channel proteins)
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Cell Recognition
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ID tags, to identify cells to the body's immune system
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Enzymatic proteins
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carry out metabolic reactions
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beyond the plasma membrane is the
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extracellular matrix ECM
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mixture of glycoproteins
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secreted by animal cells to help coordinate the behavior of all cells in a tissue
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ECM attaches through connecting proteins that bind to membrane proteins called
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integins
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Integins
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span the plasma membrane and connect to microfilaments of the cytoskeleton
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Cells have selective permeability
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only allows some material to pass
this is why cells have protein channels |
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DIFFUSION
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the movemnet of molecules down their concentration gradient
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OSMOSIS
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diffusion of water through aa semi-permiable membrane (cell-membrane)
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TONICITY
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ability of a solution to cause a cell to gain or lose water
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SOLUTE
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a substance dissolved in a solution
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HYPERTONIC SOLUTION
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contains a higher concentrate of solute than the cell
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HYPOTONIC SOLUTION
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contains lower concentration of solute than the cell
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ISOTONIC SOLUTION
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contains equal concentrations of solute as the cell
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movement of water into a cell creates
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osmotic pressure
can cause cell to swell and burst |
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OSMOREGULATION
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control of water balance
prevents excessive uptake and excessive water loss |
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SELCTIVE DIFFUSION
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allows molecules to pass through open channel in either direction
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FACILITATED DIFFUSION
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net movement of a molecule down its concentration gradient by specific carrier proteins
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Faciliated Diffusion
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AQUAPORINS transport protein responsible for rapid diffusion of H20 in and out of plant, blood, and kidney cells
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ACTIVE TRANSPORT (NEED ATP)
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movement of molecules across a membrane against a concentration gradient
requires energy proton pump Ex. sodium-potassium pump |
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Material can be moved in and out by
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vesicles
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exocytosis
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EXITS releases material
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endocytosis
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ENTERS envelopes material
phagocytosis pinocytosis receptor mediated |
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PHAGOCYTOSIS
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PAC MAN eating food
the engulfment of particulate material |
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PINOCYTOSIS
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PAC MAN DRINKING PINO COLADA
engulfment of liquid |
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Receptor Mediated
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specific
uses receptor |
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90% of a cells life is in
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Interphase
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