IB Biology: Biochem
33 flashcards · Other · by Gabrielle Wong
Metabolism: the chemical processes that take place within an organism
Metabolism consists of catabolism (catastrophe = break apart) and anabolim (build a bear)
Anabolism: formation of more complex molecules from monomer parts condensation reactions produces water
Anabolism is a type of metabolism.
Catabolism: formation of more simple molecules by breaking apart polymers. hydrolysis reactions uses water
Catabolism is a type of metabolism.
Carboyhydrate: sugar, often in ring form Joined together with glycosidic bonds can be single sugars (monosacchardie), two sugars (disaccaride) or many sugars (polysaccharides) ex. glucose
Monosaccharides: d-ribose, alpha glucose, beta glucose Disaccharaides: maltose, sucrose, fructose Polysaccharides: amylose, amlyopectin, glycogen, cellulose
Lipid: Molecule used for energy, making complex molecules such as steroids and hormones, and in cell membranes; there are many more C-H bonds than C-O bonds; they are made of fatty acids and are insoluble in water Joined togeter with ester bonds
Saturated: mx number of hydrogens attached Unsaturated: double bonds between carbon (cis = same side, trans = different) Hydrogenated = change from liquid to solid by adding Hs Triglyceride: 1 glycerol and 3 fatty acid tails Have twice the energy content of carbs
Energy: carbs are found in liver and muscle tissue, lipids are found in adipose fat cells carbs are released faster than lipids lipids have twice the energy content of carbs carbs are used in the short-term, whereas lipids are used for the long-term carbs are more accessible than lipids because carbs are soluble and can be transported in water as a result, lipids won't upset osmotic balances
Common question: compare energy potential of lipids and carbs
Protein: molecule formed through the specific combination and shaping of around 20 amino acids formed through chains of amino acids put together with protein synthesis joined together with peptide bonds
Common functions of proteins and examples: Enzyme (catalyzing reacitons): catalase, amylase, lipase, lactase Strength and structure: collagen and spider silk Immunity and defense: immunoglobin, fibrin Transportation: hemoglobin, transferrin Hormones (regulation of body activity): insulin Muscle contraction and movement: actin
Denaturation of proteins: disruption that breaks shape and destroys function 2 things that can denature proteins temperature pH
Temperature can lead to denaturation beacuse high temperatures = high energy, which stresses the bonds holding the protein together. pH can lead to denaturation becasue the charges of ions (in either direction) can lead to disruption of the hydrogen bonds holding a protein together
Enzyme: globular proteins that catalyze the rate of reaction by holding substrate in and decreasing activation energy. Enzymes are specific and reusable. Influencing factors are temperature, pH, and substrate concentration.
Example of enzyme use: Lactase to catalyze reaction of lactose breaking down into glucose and galactose - held in place with calcium aginate beads. Benefits: People with lactorse intolerance can consume dairy products Sweeter taste Less crystallization = better for some frozen products Faster fermentation = better for some yogurts and cheeses
Allosteric inhibition: concept that the binding of one substance to an enzyme decreases affinity for substrate at a different active site.
Term related to enzymes
Active site: The part of an enzyme which attaches to the substrate to catalyze the reaction
Substrate will always bind to active site and then reaciton will occur (activation energy needed is lowered because substrate is held in correct position for reaction to occur)
Nucleic Acid: A molecule made out of nucleotides that form the polymers of DNA and RNA Nucleotide: Building block of DNA - nitrogen base, sugar, and phosphate held together with phospholite ester bonds
Sugar: ribose or deoxyribose Phosphate Base: adenine, guanine, thymine, cytosine, uracil
DNA Structure: double-helix each strand has a sugar-phosphate backbone runs antiparallel - one end is 5', the other is 3' complementary base pairing: AT / GC A and G are purines T and C and pyrimidines
Differences from RNA RNA is single stranded sugar in RNA is ribose instead of deoxyribose RNA has uracil instead of thymine RNA makes DNA useful - mRNA and tRNA
Replication: the process where two strands of DNA are made (during S phase of interphase) from one mother strand of DNA using semi-conservative replication. Occurs in the nucleus of eukaryotes.
Process: Enzyme helicase braeks hydrogen bonds betweeen bases DNA Polymerase creates covalent bonds and joins new nitrogen bases to each strand this is a semi-conservative process becuase half of the each new strand comes from the original parent strand
Semi-conservative replication: iidea that something is made of one old and one new part. Characteristic of DNA replication
DNA replication is a semi-conservative process becuase half of the each new strand comes from the original parent strand. Shown by the experiment of Meselson and Stahl: e. coli DNA replicated density measured with caesium chloride gradually decreases in density when moved from 15N to 14N solution
Transcription of DNA: process through which mRNA copies DNA code to make an amino acid mRNA copies off the anti-sense strand so that its code is identical to the sense strand
Process: RNA polymperase is an enzyme that breaks apart the bonds and creates the covalent bodns with completementary base pairings formation of a single-strand of mRNA (messenger RNA)
Translation: process through which mRNA is used to create a chain of amino acids in a ribosome - leads to the formation of a polypeptide
Process: mRNA leaves nuclear pore, travels to rough ER or ribosome anticodons, each with a specific amino acid on its end, pair to codons (set of three bases) on mRNA then chained togehter to form a polypeptide triplet: set of two codons Process ends with a stop codon
Taq DNA polymerase: type of DNA polymerase used in PCR to quickly replicate DNA (enzyme is found in hot springs)
Process: Head to 95 C to break hydrogen bonds lower temperature, bonding of primers enzyme pairs over 1000 nucleotides a minute at 72 C
Cellular respiration: The chemical process converting glucose into waste products (carbon dioxide and water) and energy, which is stored in the form of ATP
Starts in cytoplasm of a cell (glycolysis), moves to mitochondrion in a eukaryote
Glycolysis: process through which one molecule of glucose is convereted into two molecules of pyruvate, leading to a net gain of 2 ATP
Glycolysis occurs regardless of whether respiration is aerobic or anaerobic
Comparison of anaerobic and aerobic respiration: both start with glycolysis only aerobic respiration needs oxygen aerobic respiration is far more efficient, producting over 30 ATP per molecule of glucose anaerobic respiration is used when oxygen supply is low anaerobic respiration produces: lactate (animals, reversible reaction) or CO2 and ethanaol (plants) aerobic respiration proudces CO2 and H2O
Comparison needs similarities AND differences!
Alcoholic fermentation: type of anaeroic respiration, pyruvate is converted into ethanol, with a byproduct of CO2
Used in plants and in yeast (used to make bread)
Lactic acid fermentation: type of anaerobic respiration, pyruvate is converted into lactate This reaciton is reversible.
Used by animals when O2 levels are too low to support aerobic respiration
Aerobic respiration: pyruvate is used in the Krebs cycle, which occurs in the mitochondria
Used in O2 rich conditions
Respirometer: device used to measure the rate of respiration
Components: alkali to absorb CO2 organism in sealed contained capillary tube connected to tube of fluid (if working, the volume of air will decrease and the fluid will move towards container as oxygen is ued)
Photosynthesis: process through which plants convert light energy into useable energy in the form of glucose
Occurs in the chloroplast large SA to absorb light small space to accumulate proteins in thykaloids stroma's fluid contains enzymes for Calvin cycle
Process of photosynthesis: Light-dependent reactions, in which chlorophyll is converted into ATP and water undergoes photolysis, meaning that it is split apart by light, producing oxygen, hydrogen ions, and electrons Light-independent reactions, in which fixation occurs (CO2+H20=C6H12O6+O2)
The pigment that absorbs light energy is chlrophyll - will absorb red and blue, but reflects green (explains why green light would not be as good for a plant as blue light in terms of maximizing efficiency) Factors that can affect this rate: time of day - more light during the day intensity of light - more light absorbed, but eventually plateaus once active sites of an enzyme are filled temperature - same reasons as enzymes concentration of CO2 - plateaus once active sites full wavelength of li…
Ways to measure the rate of photosynthesis: Release of oxygen by acquatic plants: because oxygen is a waste product of photosynthesis Measuring the acidity of water, because CO2 forms a weak acid in water, so removing CO2 will increase pH track biomass, since photosynthesis is necessary for growth using radioactive CO2 and measuring its uptake using a respirometer to indirectly track rate of photosynthesis
Note that not all of these are direct methods
Hydrogen bonds: A molecular attraction between the positively charged region around a hydrogen atom and the negatively charged region of oxygen, fluorine, or nitrogen in an adjacent molecule.
Hydrogen bonds form betweeen water molecules because it is dipolar and has different charges and different ends.
Specific heat capacity: means that significant levels of energy are needed to break bonds, so water can absorb heat without a large temperature increase
This is a property of water. stable acquatic environment stabilize land temperatures even distribution of heat and stable internal temperature
High latent heat of evaporization: means that becuase bonds break and reform constnatly, a high level of energy is needed and absorbed when water becomes water vapour (relatively high boiling point)
This is a property of water. sweat is a coolant absorption of heat when it evaporates
Cohesive/adhesive properties: means that bonds form a weak attraction between itself (cohesive) and other (adhesive) surfaces
This is a property of water. surface tension of water - water striders water is able to form droplets water can move up and down the vascular tubes of plans
Solubility: dissolution of polar substances in water Occurs becuase hydrogen bonds disurb the molecules of a compound
This is a property of water. containment/storage of materials in plasma travel and transport ex. blood distribution of nutrients wnd wastes envrionment for metabolic reactions ex. cytoplasm, stroma