ch.4 cellular respiration Flashcards
What are the two types of metabolic pathways and reactions?
anabolism and catabolism
Define anabolism
small molecules are built up into larger ones; requires energy (ATP)
define catabolism
larger molecules are broken into smaller ones; releases energy
define cellular metabolism
sum of all chemical rxns in a cell
what does anabolism provide materials for?
cell maintenance, growth, and repair
what is the main type of anabolic process? describe in
dehydration synthesis; joins simple sugar molecules to form larger molecules of gylcogen
what type of organic molecules can dehydration synthesis be used for?
-carbohydrates (simple sugar to glycogen)
-lipids (glycerol and fatty acids to triglyceride)
-protein (joining amino acids)
-nucleic acids
what type of bonds connects amino acids to form proteins?
peptide bond
what is the main type of catabolic reaction? describe it
hydrolysis; decomposes carbohydrates, lipids, and proteins
what is a product in all dehydration synthesis rxns but a reactant in all hydrolysis rxns?
water
hydrolysis is the ___ of dehydration synthesis
reversal
why doesn’t hydrolysis occur automatically?
-water soluble substance will dissolve in water but won’t undergo hydrolysis
-the process requires enzymes
why might some metabolic rxns not be reversible?
the enzyme needed for the anabolic rxn may be different than the ezymes needed for the catabolic rxn
true or false
catabolism and anabolicm must be controlled so that the breakdown or energy releasing rxns occur at rates adjusted to the requirements of the build up or energy utilizing rxns
true
define intermediary metabolism, primary metabolism, and secondary metabolism
-process that obtain, release, and use energy
-products of metabolism essential to survival
-not essential, but may provide advantage (plants)
what is the main job of enzymes
controling the rate of chem rxns
true or false
energy releasing rxns don’t need to occur at rates to balance energy utilizing
false
metabolic rxns require ___ energy before they process
activation
in a lab what is used to increase the rate of rxns?
heat
most enzymes are globular proteins that catalyze specific chem rxns by …
lowering activation energy
how are most enzymes named?
dervided from the names of the substrate, with the suffix -ase
define an activation site. how does this help with the chem rxn
-a region of enzyme that temporarily combines with specific part of a substrate, forming an enzyme-substrate complex
-this interaction strains chem bond in substrate so that the chem rxn requires less energy
what does the rate of enzyme-catatlyzed rxns depend on?
-rxn is faster if rate of enzyme or rate of substrate increases
what is critical to an ezymes function? what can damage this?
-their configuration (shape)
-excessive heat, radiation, electricity, certain chemicals, fluids with extreme pH values
define denature
inactivation of an enzyme
how do enzyme-catalyzed rxns form metabolic pathways?
the product of one rxn is the reactant in another rxn. this process continues to happen
define metabolic pathways
lead to the synthesis or breakdown of particular biochemicals
what does a regulatory enzyme do in metabolic pathways?
sets the rate for the entire sequence of rxns
when enzymes don’t work at high substrate concentrations, it is a … Where are these enzymes located in the metabolic pathways
-rate limiting enzyme
-usually first
how does negative feedback relate to metabolic pathways?
in some pathways that product inhibits the rate limiting enzyme. accumulating product inhibits the pathways
an enzyme may be inactive until it combines with a non protein component, called a ___, which helps active site fold into right configuration
cofactor
define coenzyme. where do these coenzymes come from
-a cofactor that is an ion of an element of small organic molecule
-vitamins
define vitamin
an essential organic molecule that human cells cannot synthesize and therefor must come from diet; they can function repeatedly,
define metabolone
small molecules that are part of metabolism
define energy. what are common forms of energy? energy cannot be created nor destroyed but it can …
-the capacity to change something/do work
-heat, light, sound, chemical energy
-change forms
all metabolic rxns involve ___, they must use …
-energy
-chemical energy
what is the primary enegry carrying molecule in a form that cells can use? what does this molecule consist of?
-adenosine triphosphate (ATP)
-sugar, 3 phosphate, adenine
how is energy released from ATP? what is the resulting molecule of this action?
-breaking of the high energy bonds between the 2nd and 3rd phosphate
-adenosine diphosphate (ADP)
what is the name of the process used to describe ATP being converted to ADP?
phosphorylation
what is the process that releases energy from glucose, that is used to power cellular respiration?
oxidation
what are the 3 series or rxns in cellular repiration? list if they are anaerobic or aerobic
-glycolysis (anaerobic)
-citric acid cycle (aerobic)
-electron transport chain (aerobic)
what are the reactants of cellular respiration? what are the products of cellular respiration?
-glucose and oxygen
-carbon dioxide, water, energy (ATP and heat)
define aerobic rxns. define anaerobic rxns.
-require oxygen
-don’t require oxygen
describe glycolysis
6-carbon sugar glucose is broken down in the cytosol into two 3-carbon pyruvic acid molecules with a net gain of 2 ATP and the release of high energy electrons. 2 ATP are required to start this process but 4 ATP are created, so there is a net gain of 2 ATP
describe the citric acid cycle
-the 3-carbon pyruvic acids generated from glycolysis enter the mitochondria separately. each lose a carbon (generating C02) and is combines with coenzyme to form 2-carbon acetyl CoA. more high energy electrons are releases
-each acetyl CoA combines with a 4-carbon oxaloacetic acid to form 6-carbon citric acid. for each citric acid cycle, a series of rxnz remove 2 carbons (generating CO2), synthesis 1 ATP, and release more high energy electrons
describe the electron transport chain
the high energy electrons still contain most of the chemical energy of the original glucose molecule. special carrier molecules bring the high-energy electrons to a series of enzymes that transfer much of the remaining energy to ATP. the electrons eventually combine with hydrogen ions and an oxygen atom to form water. oxygen is the final electron acceptor, that is why it is aerobic
what must occur so glycolysis can continue? what happens when this doesn’t occur?
-NADH + H+ must be present; this happens when oxygen is present
-NADH + H+ gives its electron and hydrogen back to pyruvic acid in a rxn that forms lactic acid
what does the build up of lactic acid cause?
it inhibits glycolysis and ATP production declines. the lactic acid diffuses into blood when oxygen levels return to normal the liver converts lactic acid back to pyruvic acid so it can enter cellular respiration
what are the products of aerobic cellular respiration?
CO2 & less than 36 ATP
when does aerobic cellular respiration start?
when the pyruvic acid (from glycolysis) moves from the cytosol into the mitochondria. a bridge rxn creates NADH, CO2, and 2-carbon acetic acid. acetyl CoA goes into the citric acid cycle
the ingestion of ___ kills cells by blocking the enzyme that helps with the rxn for the production of aceytl CoA
arsenic
what are the consequences of the citric acid cycle?
-one ATP per citric acid molecule
-for each citric acid molecule, 8 hydrogen elections are transferred to electron carrier
-as 6-carbon citric acid reacts to form 4-carbon oxaloacetic acid, 2 CO2 are produced
what happens as the electron move down the electron transport chain? what happens when oxygen isn’t present?
-they lose energy
-the electrons cannot pass through the transport chain and aerobic rxns stop
what may happen to excess glucose in cells?
they may enter anabolic carbohydrate pathways and be linked into glycogen (storage form)
what happens after a meal when blood glucose is high? what happens between meals when blood glucose is lwo?
-liver cells obtain glucose from the blood and synthesize glycogen
-the rxn is reversed and glucose is released into the bloodq
true or false
the body has an almost unlimited capacity for glucose
true
can lipids and proteins be used to release energy for ATP synthesis?
yes
the info that instructs a cell to synthesize a protein is held in the sequence of building block in ___. the correspondence between DNA info and particular amino acid constitutes the ___
-DNA
-genetic code
define gene. define genome.
-a DNA sequence that contains the info for making a particular polypeptide
-the complete set of genetic instructions in a cell
define exome. define gene expression
-a small part of the human genome that encodes protein
-controls which proteins are porduced under particular circumstances and the amounts produced
what are the building blocks of nucleic acids? what are they made of?
-nucleotides
-5-carbon sugar, phosphate group, nitrogenous base
how to polynucleotide chains form in DNA and RNA?
dehydration syntheis joins sugars and phosphates forming backbones
what are the 4 types of DNA bases? how do they bind?
-adenine, guanine, thymine, cytosine
-A to T, G to C
in the nucleus, DNA is wound around proteins called ___, clustered in groups to form chromatin
histones
describe the DNA replication process
-hydrogen bonds break between base pairs
-the strands unwind and separate, exposing unpaired bases
-new nucleotide pair with exposed bases, forming hydrogen bonds
-enzymes knit together the new sugar-phosphate back bone
-2 complete DNA molecules result
what are the 4 nitrogenous bases in RNA?
-adenine, uracil, cytosine, guanine
transcription occurs in the ___ and is ___ to ___
translation occurs in the ___ and is ___ to ___
protein synthesis occurs in the ___ and is ___ to ___
-nucleus; DNA; RNA
-cytoplasm/ribosome; RNA; amino acid
-cytoplasm/ribosome; amino acid; protein
describe the process of transcription
-RNA polymerase binds to the DNA base sequence of a gene
-the enzyme unwinds and exposes part of the DNA molecule
-RNA polymerase moves along one strand of the exposed gene and catalyzes synthesis of a mRNA
-when RNA polymerase reaches the end of the gene, the newly formed mRNA is release
-DNA rewinds and closes
-the mRNA passes through a pore in the nuclear envelope and enters cytoplasm
describe translation
-a ribosome binds to the mRNA near the codon at the beginning of the messenger strand
-a tRNA molecule that has the complementary anitcodon brings its amino acid to the ribosome
-a second tRNA brings the next amino acid to the ribosome
-a peptide bond forms between the 2 amino acid and the first tRNA is released
-this process repeats for each codon in the mRNA sequences, forming a chain of amino acids
-the growing amino acid chain folds into the unique conformation of a protein
the human genome sequence is ___ the same among individuals. what could the different part affect?
-99.9%
-health, appearance
define mutation. what can happen to the bases?
-changes in the DNA sequence due to errors in DNA replication
-changed, added, deleted
what are the 2 types of mutation? describe them
-spontaneous: arise from the chemical tendency of free nitrogenous bases to exist in 2 slightly different structures
-induced: response to exposure to certain chemicals or radiation (mutagen)
most mutations affect health.
true or false
false; most don’t have affect health
how does the body protect against mutations?
-DNA repair restores the original DNA sequence
-since some amino acids correspond to one or more codon and 2 or 3 codons specify the same amino acid differ in the 3rd base, a mutation in the 3rd base could code the same amino acid
-a person has 2 copies of each chromosome
how does timing of mutation affect health?
- a mutation in sperm or egg cells are repeated over and over; causing inherited disease or trait
-a mutation in the body cell of an adult would most likely have no affect, unless cancer
