The sum total of chemical reactions in the cell constitutes
air: aerobic respiration—respiratory process that requires oxygen
without: anaerobic respiration—respiratory process that does not require oxygen.
down: catabolism—cellular processes in which larger molecules are broken down into smaller ones.
with: coenzyme—substance that unites with a protein to complete the structure of an active enzyme molecule
undoing: deamination—process that removes nitrogen-containing portions of amino acid molecules
change: mutation—change in genetic information
spread out: substrate—substance upon which an enzyme acts
under: substrate—substance upon which an enzyme acts
causing to ferment: enzyme—protein that speeds up a chemical reaction without itself being consumed
proteins that control the rate of each reaction
they are not consumed and can, therefore, function repeatedly
Each enzyme is specific, acting only on a particular molecule
larger molecules are constructed from smaller ones, requiring input of energy.
provides all the materials required for cellular growth and repair
larger molecules are broken down into smaller ones, releasing energy
a form of anabolism that produces water
a form of catabolism that uses water to form a product
What are the general functions of anabolism and catabolism?
create and release energy
What type of molecule is formed by the anabolism of monosaccharides? Of glycerol and fatty acids? Of amino acids?
-many simple sugar molecules (monosaccharides) to form larger molecules of glycogen
-Glycerol and fatty acid molecules also join by dehydration synthesis in fat (adipose tissue) cells to form fat molecules
-In cells, dehydration synthesis also builds protein molecules by joining amino acid molecules
Each enzyme is specific, acting only on a particular molecule, called its
During an enzyme-catalyzed reaction, regions of the enzyme molecule called ? temporarily combine with portions of the substrate, forming an enzyme-substrate complex
active sites .
sequences of enzyme-controlled reactions, that lead to synthesis or breakdown of particular biochemicals
ineffectual at high substrate concentrations
Binds with an enzyme that is inactive which helps the active site attain its appropriate shape or helps bind the enzyme to its substrate
A cofactor may that is an ion of an element, such as copper, iron, or zinc, or a small organic molecule
are essential organic molecules that human cells cannot synthesize (or may not synthesize in sufficient amounts) and therefore must come from the diet.
How can an enzyme control the rate of a metabolic reaction?
The rate at which a metabolic pathway functions is often determined by a regulatory enzyme that catalyzes one of its steps. The number of molecules of such a regulatory enzyme is limited. Consequently, these enzymes can become saturated when the substrate concentration exceeds a certain level
How does an enzyme "recognize" its substrate?
depends upon the shape of an enzyme molecule. That is, each enzyme's polypeptide chain twists and coils into a unique three-dimensional conformation that fits the particular shape of its substrate molecule.
How can a rate-limiting enzyme be an example of negative feedback control of a metabolic pathway?
Often the product of a metabolic pathway inhibits the rate-limiting regulatory enzyme. This type of control is an example of negative feedback. Accumulating product inhibits the pathway, and synthesis of the product falls. When the concentration of product decreases, the inhibition lifts, and more product is synthesized. In this way, a single enzyme can control a whole pathway, stabilizing the rate of production
What factors can denature enzymes?
exposure to excessive heat, radiation, electricity, certain chemicals, or fluids with extreme pH value
is the capacity to change something; it is the ability to do work.
is the process that transfers energy from molecules such as glucose and makes it available for cellular use
molecules shuttle back and forth between the energy-transferring reactions of cellular respiration and the energy-transferring reactions of the cell.
chemical process that breaks down fatty acid into molecules acetyl which bind coenzymes A, entering the citric acid cycle
How does cellular oxidation differ from burning?
Oxidation of substances inside cells and the burning of substances outside them have important differences. Burning in nonliving systems (such as starting a fire in a fireplace) usually requires a great deal of energy to begin, and most of the energy released escapes as heat or light. In cells, enzymes initiate oxidation by lowering the activation energy. Also, by transferring energy to ATP, cells are able to capture almost half of the energy released in the form of chemical energy. The rest escapes as heat, which helps maintain body temperature
the energy breakdown of glucose to pyruvic acid during cellular respiration
citric acid cycle
series of chemical reactions that oxidizes certian molecules releasing energy; Krebs Cycle
electron transport chain
(oxidative phosphorylation) series of oxidation-reduction reactions that takes high energy electrons from glycosis and the citric acid cycle to form water and ATP
reactions which require oxygen, and anaerobic
reactions, which do not require oxygen.
What are the final products of cellular respiration?
products of these reactions include carbon dioxide (CO2), water, and energy. Although most of the energy is lost as heat, almost half is captured as ATP
What is the result of glycolysis?
ATP and NADH. NADH delivers these high-energy electrons to the electron transport chain elsewhere in the mitochondria, where most of the ATP will be synthesized
organic compound formed from pyruvic acid during the anaerobic reactions of cellular respiration
What is the role of oxygen in cellular respiration?
Oxygen acts as the final electron acceptor at the end of the electron transport chain, enabling the chain to continue processing electrons and recycling NAD+.
Under what conditions does a cell produce lactic acid?
anaerobic conditions - the electron transport chain has nowhere to unload its electrons, and it can no longer accept new electrons from NADH. As an alternative, NADH + H+ can give its electrons and hydrogens back to pyruvic acid
acetyl coenzyme A
Intermediate compound produced from the oxidation of carbohydrates and fats
State the products of the aerobic reactions.
carbon dioxide and water, the aerobic reactions yield up to thirty-six ATP molecules per glucose
List the products of the citric acid cycle
Explain the function of the electron transport chain
a series of enzyme complexes that carry and pass electrons along from one to another. These complexes dot the folds of the inner mitochondrial membranes. The electron transport chain passes each electron along, gradually lowering the electron's energy level and transferring that energy to ATP synthase
Discuss fates of glucose other than cellular respiration
Glucose can also react to form fat molecules, later deposited in adipose tissue. This happens when a person takes in more carbohydrates than can be stored as glycogen or are required for normal activities. The body has an almost unlimited capacity to perform this type of anabolism, so overeating carbohydrates can cause accumulation of body fat.
deoxyribonucleic acid (DNA),
genetic code (jě-net′ik kōd).
the correspondence between a unit of DNA information and a particular amino acid
The portion of a DNA molecule that contains the genetic information for making a particular protein
The complete set of genetic instructions in a cell
part of a nitrogen containing base that is part of a DNA and RNA and has two organic rings; adenine and guanine
part of a nitrogen containing base that is part of a DNA and RNA and has two organic rings; thymine, cytosine and uracil
complementary base pairs
Hydrogen bonded adenine and thymine or guanine and cytosine in DNA. Adenine bonds to uracil in RNA
the process that creates an exact copy of a DNA molecule. It happens during interphase of the cell cycle
What is the function of DNA?
contains the information that instructs a cell to synthesize a particular protein
What is the structure of DNA?
double-stranded DNA molecule twists, forming a double helix
How does DNA replicate?
hydrogen bonds break between the complementary base pairs of the double strands. Then the strands unwind and separate, exposing unpaired bases. New nucleotides pair with the exposed bases, forming hydrogen bonds. An enzyme, DNA polymerase, catalyzes this base pairing. Enzymes then knit together the new sugar-phosphate backbone. In this way, a new strand of complementary nucleotides extends along each of the old (original) strands. Two complete DNA molecules result, each with one new and one original strand
are molecules differ from DNA molecules in several ways. RNA molecules are single-stranded, and their nucleotides have ribose rather than deoxyribose sugar
messenger RNA (mRNA).
manufacturing a complimentry RNA from DNA
set of three nucleotides in a messenger RNA molecule corresponding to one of the 20 types of amino acids
RNA making a protein at the ribosomes
the series of codons of the mRNA is translated from the "language" of nucleic acids to the "language" of amino acids
Comparison of DNA and RNA Molecules
Main location Part of chromosomes, in nucleus Cytoplasm
5-carbon sugar Deoxyribose Ribose
structure Double-stranded Single-stranded
included CGAT CGAU
Major functions Contains genetic code for protein synthesis/ replicates prior to mitosis Messenger RNA carries transcribed DNA information to cytoplasm and acts as template for synthesis of protein molecules; transfer RNA carries amino acids to messenger RNA; ribosomal RNA provides structure for ribosomes
transfer RNA (tRNA),
transcribed in the nucleus and aligns amino acids in a way that enables them to bond to each other.
sequence of three nitrogen bases on tRNA
An anticodon bonds only to the complementary mRNA codon. In this way, the appropriate tRNA carries its amino acid to the correct place in the mRNA sequence
ribosomal RNA (rRNA)
helps build ribosomes
Transcription (In the Nucleus) - steps (6)
1. RNA polymerase binds to the DNA base sequence of a gene.
2. This enzyme unwinds a portion of the DNA molecule, exposing part of the gene.
3. RNA polymerase moves along one strand of the exposed gene and catalyzes synthesis of an mRNA, whose nucleotides are complementary to those of the strand of the gene.
4. When RNA polymerase reaches the end of the gene, the newly formed mRNA is released.
5. The DNA rewinds and closes the double helix.
6. The mRNA passes through a pore in the nuclear envelope and enters the cytoplasm
Translation (In the Cytoplasm) - steps (7)
1. A ribosome binds to the mRNA near the codon at the beginning of the messenger strand.
2. A tRNA molecule that has the complementary anticodon brings its amino acid to the ribosome.
3. A second tRNA brings the next amino acid to the ribosome.
4. A peptide bond forms between the two amino acids, and the first tRNA is released.
5. This process is repeated for each codon in the mRNA sequence as the ribosome moves along its length, forming a chain of amino acids.
6. As the chain of amino acids grows, it folds, with the help of chaperone proteins, into the unique conformation of a functional protein molecule.
7. The completed protein molecule (polypeptide) is released. The mRNA molecule, ribosome, and tRNA molecules are recycled.
How is genetic information carried from the nucleus to the cytoplasm?
messenger RNA (mRNA). RNA nucleotides form complementary base pairs with one of the two strands of DNA that encodes a particular protein
How are protein molecules synthesized?
Synthesizing a protein molecule requires that the specified amino acid building blocks in the cytoplasm align in the proper sequence along an mRNA. A second type of RNA molecule, transcribed in the nucleus and called transfer RNA (tRNA), aligns amino acids in a way that enables them to bond to each other
How is gene expression controlled?
Proteins called transcription factors activate certain genes, moving aside the surrounding histone proteins to expose the promoter DNA sequences that represent the start of a gene. These actions are called "chromatin remodeling," and they control which proteins a cell produces and how many copies form under particular conditions
change in a gene
single nucleotide polymorphisms
genetic variants with no detectable effects
Anything that causes mutation
DNA damage response,
Cells detect many mutations and take action to correct the errors. Special "repair enzymes" recognize and remove mismatched nucleotides and fill the resulting gap with the accurate, complementary nucleotides. This mechanism restores the original structure of the double-stranded DNA molecule
Distinguish between a mutation and a SNP
mutations affect how we look or feel, SNP we do not notice
How do mutations arise?
spontaneously or induced
How do mutations affect health or appearance?
Disease may result from a mutation, whether spontaneous or induced
Describe protections against mutation.
Cells detect many mutations and take action to correct the errors. Special "repair enzymes" recognize and remove mismatched nucleotides and fill the resulting gap with the accurate, complementary nucleotides. This mechanism, called the DNA damage response, restores the original structure of the double-stranded DNA molecule.
Explain how metabolic pathways are linked and intersect
the products of one reaction are starting materials for the next. These reactions form pathways and cycles that may intersect where they share intermediate compounds, each step catalyzed by an enzyme
Distinguish between catabolism and anabolism
anabolism creates energy, catbolism releases energy
Distinguish between dehydration synthesis and hydrolysis
Dehydration is when two molecules come together to produce a water (by bonding OH and H so you have H2O.) Hydrolysis is doing that in reverse. Breaking the H2O into H and OH and therefore breaking the bond.
Give examples of a dehydration synthesis reaction and a hydrolysis reaction.
dehydration synthesis of proteins, which requires reaction between amino acids in order to release proteins and water as products
-The breakdown of triglyceride to form glycerol and fatty acids
State two factors that control the rate of an enzyme-catalyzed reaction
heat and the number of enzyme or substrate molecules in the cell.
A cell has ? types of enzymes and metabolic reactions
Discuss the relationship between a coenzyme and a vitamin
vitamins provide coenzymes, like enzymes
Explain the importance of ATP and its relationship to ADP
ATP (Adenoside triphoshpate) is a molecule that carries energy in that the cell can use. When an ATP loses its terminal phosphate it becomes an ADP (adenosine diphosphate) molecule.
Identify the final acceptor of the electrons released in the reactions of cellular respiration
Excess glucose in cells may link and be stored as
If a DNA strand has the sequence ATGC then the sequence on the complementary DNA strand is
If one strand of a DNA molecule has the sequence of ATTCTCGACTAT, the complementary mRNA has the sequence