IB Bio - Metabolic Reactions

enzymes

enzymes

globular proteins with tertiary or quaternary structure that catalyse biochemical reactions; not consumed during reactions

active site

where specific substrates can attach to and where reactions are catalysed

the induced fit model

the model that shows that when the substrate enters the active site, it triggers a change in the 3D shape of the enzyme that allows a tighter fit

lock and key model

the model that shows that enzyme and substrate complement each other precisely in terms of shape and chemical properties; not used anymore

things that can affect the rate of activity in enzymes

temperatur, pH, substrate/enzyme concentration

denaturations

when the tertiary or quaternary conformation (beta sheets and alpha helices) of a protein is destroyed; and therefore, there is no longer a functional active site

immobilised enzymes

enzymes that are fixed to a static surface to prevent enzyme loss; they can be reusec

lactase immobilisation with alginate beads

milk containing lactose is passed through alginate beads containing lactase; the immobilised lactase converts lactose into glucose and galactose as the milks flows through

nucleotides

the basic structure of DNA and RNA; monomers that include a pentose sugar, a phosphate group, and a nitrogenous base

DNA bases

adenine, thymine, guanine, and cytosine

RNA bases

adenine, uracil, guanine, and cytosine

purines

bases with two rings in their structure; adenine and guanine

pyrimidines

bases with one ring in their structure; thymine, uracil, and cytosine

phosphodiester bond

the covalent bond that links nucleotide units together to form a polynucleotide; forms between the phosphate group attached to the 5’ of one sugar and the hydroxyl group attached to the 3’ of another sugar

replications

the formation of a new DNA molecules during the S phase that results in two identical copies of the DNA in the daughter cells

enzymes used during replications

• helicase: unwinds the double helix and separates the two DNA strands by breaking the hydrogen bonds between the bases

• DNA polymerase starts making the new strands of DNA using the parent strands as templates

transcription

the coding information is copied or transcribed into the mRNA; the single stranded mRNA that is made follows the complementary base pairing rules of DNA except uracil replaced thymine in mRNA

translation

mRNA binds to a ribosomes to synthesize polypeptides according to the genetic code

tRNA

transfer RNA brings a specific amino acid to the mRNA; they have an anti-codon that pairs with a codon of the mRNA

cellular respiration

the gradual and controlled release of energy by breaking down organic compounds ro produce ATP

3 main processes of cellular respiration

glycolysis, the Krebs cycle, the electron transport chain

anaerobic respiration

cell respiration that takes place without the presence of oxygen; occurs in the cytoplasm as only glycolysis is involved; produced 2 ATP

alcohol fermentation

when yeast respired anaerobically to produce ethanol and carbon dioxide

lactic acid fermentations

anaerobic respiration in animals when lactate is produced

aerobic cell respiration

cell respiration that takes place with the presence of oxygen; occurs in the cytoplasm and mitochondria as glycolysis, the Krebs cycle, and the electron transport chain are all involved; produced 36 ATP; produced carbon dioxide and water

photosynthesis

the reaction of carbon dioxide and water using energy from light to produce carbohydrates and releasing oxygen as a waste product

chloroplast

the organelle where photons are captured and photosynthesis takes place

the pigments that makes chloroplasts look green

chlorophyll a and chlorophyll b

the action spectrum

shows the efficiency of photosynthesis or rate of photosynthesis achieved over the various wavelengths of light from the visible spectrum

the absorption spectrum

shows which wavelength of visible light is absorbed by a particular photosynthetic pigment such are chlorophyll a or b as measured by a spectrometer

photolysis

the stage of photosynthesis in which water is split by light by photons; generates hydrogen ions (which is used later in photosynthesis), electrons (which is used to generate ATP), and oxygen (a waste product); light-dependent

the Calvin cycle

the light-independent reaction where carbon dioxide reacts with water to produce carbohydrates and oxygen

limiting factors of photosynthesis

light, carbon dioxide, temperature

the earliest photosynthetic organisms

prokaryotes called cyanobacteria that appeared on Earth around 3500 million years ago

chromatography

the technique used to separate the mixture of substances based on the movement of the different substances on a piece of paper by capillary action

ethanol in chromatography

used to separate the pigments

codon

a set of three consecutive bases in RNA

RNA polymerase

separates DNA strands of the double helix and joins the ribonucleotides together by phosphodiester bonds to form mRNA