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83 Cards in this Set
- Front
- Back
_____ catalyze all cellular reactions
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enzymes
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_____ increase the probability that chemicla reactions will occur
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enzymes
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_____ are not changed by the reactions, and can be reused
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enzymes
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______ activity is highly specific
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enzyme
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_____ act on substrates
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enzymes
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______ lower the activation energy so a reaction is more likely to occur
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enzymes
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_____ weaken chmeical bonds in the substrate
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Enzymes
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____ ____ = Lock and Key model
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Old model
(perfect fit) |
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____ ____ = substrate, active site, product
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Induced fit
(not perfect, like a temperpedic mattress it forms to fit the body) |
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____ can be named in one of two ways
- by thier function - by the sbustrate on which they act * Examples: - sucrase - lipase - oxidase - hydrolase |
Naming enzymes
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_____ act thorugh enzyme-substrate complexes
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Enzymes
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_____ align substrate molecules in such a way that a reaction is energetically favorable
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Enzymes
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______ bind to the enzyme at the active site, which is specific to the substrate
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Substrates
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____ lower the activation energy so a reaction is more likely to occur
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Enzymes
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Enzymes weaken chemical bonds in the ______
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substrate
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____ can:
- be made entirely of protein or - have a complementing substance, such as: - a metal ion (cofactor) - an organic molecule (coenzyme) |
Enzymes
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Carbonic Anhydrase
* The gray sphere is zinc ( a metal) acting as a _____ |
cofactor
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______- a subclass of cofactors that are organic molecules (but not proteins)
* Ascorbic acid - Vitamin C acts as an electron carrier |
Coenzymes
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____ often team up in metabolic pathways
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enzymes
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A metabolic pathway is a sequence of _____ _____
- each reaction is catalyzed by a different enzyme - the product of one reaction serves as the substrate for the next |
chemical reactions
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Enzyme activity is regulated and can be _____
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inhibited
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_____ inhibition hinders metabolic pathways
- it inhibits an enzyme in the pathway so no product is available to feed the next reaction |
feedback
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Other types of _____ include
- changing the shape of an active site (noncompetitive inhibition) - blocking an active site (competitive inhibition) |
inhibition
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Energy in the form of ____ is required for metabolism
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ATP
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____ is the cellular "energy currency," providing energy for:
- movement - cell division - protein synthesis, etc. |
ATP
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_____ is released from ATP when the bond holding the last phosphate group on the molecule is broken, producing
- adenosine diphosphate (ADP) - a free phosphate group |
Energy
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Adding a phosphate group to a molecule is called ______
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phosphorylation
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Enzymes that transfer a phosphate from one molecule to another are called _____
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kinases
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_____ cannot be stored because it is relatively unstable
- energy must be stored in more stable forms like glycogen, starch or lipids (in prokaryotes), which can then be used to form ATP |
ATP
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_____ contains stored energy that can be extracted
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Glucose
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_____ in glucose is released slowly by converting to ATP through metabolic pathways
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Energy
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Cellular respiration is a series of catabolic pathways for the production of _____
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ATP
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Cells make ____ by harvesting energy through cellular respiration
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ATP
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If oxygen is consume while making ATP, it is ______ respiration
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aerobic
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Major _____ pathways break organic molecules down - use harvested potential energy to form ATP
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Catabolic
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Formation of ATP in a cell =
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respiration
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Name the two major Catabolic Pathways
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Fermentation and Aerobic respiration
- both start with glycolysis |
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Catabolic Pathways: an overview
_______ - a 10 step pathway - aerobic resp. and ferm. both start here - all steps are catalyzed by enzymes - does not require oxygen or specialized membranes - occurs in the cytoplasm - all cells do this - because of last 3 items, is viewed as an ancient pathway |
Glycolosis
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Catabolic pathways overview, cont..
_______ _______ - is comprised of 2 pathways - Kreb's Citric Acid Cycle - an electron transport system - it follows glycolysis - requires oxygen, special membranes, special electron transporting proteins - because of last 2 items, is viewed as a more recent pathway |
Aerobic Respiration
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Step 1 in Aerobic Respiration or Fermentation:
______ -______ splits 1 glucose molecule into 2 pyruvate molecules - steps 1-3= energy requiring reactions - step 4 = molecule breaks in half - Steps 5-10 = energy harvesting reactions |
Glycolysis
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Net yield for _____ is 2 ATP; 2 NADH - is a carrier molecule that gives you lots of energy
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Glycolysis
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Aerobic Respiration, Cont:
____ _____ ____ ____ The ____ ____ extracts additional energy from pyruvate following glycolysis - synthesizes "building block" molecules - before entering ___ ____, pyruvate molecules coming from glycolysis must pass through an intermediate step |
Kreb's Citric Acid Cycle
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The Krebs Cycle Extracts more energy from ______
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Pyruvate
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The krebs cycle is also called the ____ ____ ____
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Citric Acid Cycle
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Before entering the Krebs cycle, ______:
- remove a carbon from each pyruvate molecule - combine the carbon with coenzyme A (CoA) to form acetyl - CoA - This releases 2 NADH and 2 CO2 |
enzymes
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For each two _____ molecules that enter the cycle, the following molecules are formed
- 4 CO2 - 2 ATP - 6 NADH - 2 FADH2 |
pyruvate
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Oxidative Phosphorylation is the process by which most ____ molecules form
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ATP
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Pair of _____ are passed from one chemical substance to another (electron transport), releasing energy
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electrons
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The energy released is used to combine phosphate with ADP to form _____
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ATP
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The electron transport chain is composed of electron carriers called _____
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cytochromes
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NADH and FADH2 provide the source electrons for _____ ____
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oxidative phosphorylation
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______ accepts the electron pair at the end of the chain acquires 2 protons, and becomes water
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Oxygen
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As the _____ move down the chain they use energy, which is harnessed to pump protons out of the cell (chemiosmosis)
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electrons
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The _____ outside the membrane build up a concentration gradient
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protons
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A channel opens and the ____ flow in through a channel in ATP synthesis
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protons
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ATp synthase harnesses the energy from the flowing protons to phosphorylate ADP into ____
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ATP
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Many mono-, di-, and polysaccharides can be energy sources for ______
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prokaryotes
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Chemical bonds in ____ store large amounts of energy, making ____ good energy sources
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fats
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Cells use _____ for energy when fats and carbohydrates are lacking
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proteins
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______ is the replacement of the amino group in a protein with a carbonyl group in protein breakdown
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Deamination
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Fatty acids are broken down through _____ _____
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beta oxidation
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______ respiration produces ATP using other final electron acceptors
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Anaerobic
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In _____ respiration, _____ use molecules other than oxygen as the final electron receptor in the electron transport chain
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Anaerobic
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Anaerobic respiration produces less ____ than aerobic respiration
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ATP
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______ produces ATP using an organic final electron receptor
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fermentation
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______ is used when oxygen and other alternative electron acceptors are unavailable
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Fermentation
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______ can be converted to lactic acid to reform NAD+ coenzymes so glycolysis can produce ATP from glucose
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Pyruvate
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Fermentation Pathway
* Pyruvate ---- - In our muscle cells |
Lactate
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Fermentation Pathway
* Pyruvate ------ - in yeast cells - used commercially to produce risen bread and alcoholic beverages |
CO2 + ethanol
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______ can be identified by their fermentation product
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Prokaryotes
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______ respiration produces ATP using other final electron acceptors
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Anaerobic
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______ is a process to acquire chemical energy
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Photosynthesis
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In ______, light energy is converted to chemical energy, which is stored as an organic compound
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photosynthesis
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In prokaryotes photosynthesis is carried out in the cell membrane, in eukaryotes in organelles called _______
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chloroplasts
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The gree pigment _____ absorbs light energy
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chlorophyll
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Some bacteria use other pigments, such as _________
- some archaea use bacteriorhodopsin |
bacteriochlorophylis
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______ is divided into two sets of reactions
- energy-fixing reactions: - carbon-fixing reactions |
Photosynthesis
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The Carbon-Fixing Reaction
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The Calvin Cycle
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_____ and heterotrophs get their energy and carbon in different ways
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Autotrophs
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_____ synthesize their own foods from simple carbon sources like carbon dioxide
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Autotrophs
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_______ use light as their energy source
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photoautotrophs
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_____ feed exclusively on dead organic matter-mold
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Saprobes
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The microbial ant foe is called Thelohania solenopsae is a protozoan _____; live on living material
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Parasite
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