IB Biology Review Test 1 Part 1
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Outline the thermal properties of water
Water can be vaporized, or turned from a liquid to a gas by the heat of vaporization
- heat of vaporization- the quantity of heat a liquid must absorb for 1 gram to be converted to a gaseous state
- The molecules of water can absorb a lot of heat energy (high specific heat capacity before it changes from one phase to another
- Water has a very high melting point and boiling point
Outline the cohesive properties of water
Cohesion: the attractive forces between molecules of the same type
- hydrogen bonding between water molecules results in cohesion
- Water binds to itself due to polarity of its molecules
Outline the solvent properties of water
Water is usually the dissolving agent of a solution because ionic and polar compounds can dissolve in water because it is also polar.
Explain the relationship between the properties of water and its uses in living organisms as a coolant, medium of metabolic reactions and transport medium.
Water acts as a coolant in organisms when they sweat. Because water has a high amount of vaporization when organisms sweat, it takes heat with it when it evaporates. This makes the organism cooler.
- Water can act as a transport medium because it is cohesive. Because the water can bind to itself, and all the molecules are bonded to one another, it alows for the transport of water against gravity
- ex) transpiration or water being drawn up the xylem, water up a straw
Water is a universal solvent because it can dissolve polar and ionic bonds. In order for reactions to occur, the molecules have to be dissolved. The dissolved molecules can react in the cell because the cell is mainly made up of water, which acts as a medium of metabolic reactions.
Outline the role of condensation and hydrolysis in the relationships between monosaccharides, disaccharides, and polysaccharides; between fatty acids, glycerol, and triglycerides; and between amino acids, dipeptides, and polypeptides
Condensation: a type of polymerization where monomers are covalently bonded with the release of water
- In condensation reactions, two molecules work together and form one big molecule along with water, because water is released during this reaction.
- Through condensation, monosaccharides bond to form disaccharides and polysaccharides, amino acids join to form dipeptides and polypeptides, and fatty acids join to glycerol to form triglycerides
- Hydrolysis: chemical reaction that breaks covalent bonds between monomers with the addition of water.
- Water molecules are used to make a large molecule into a small molecule
- Through hydrolysis, disaccharides and polysaccharides break down to monosaccharides, polypeptides and dipeptides break down to amino acids, and triglycerides are broken apart from glycerol to form fatty acids.
Explain the four levels of protein structure, indicating each level's significance
Primary Structure: unique linear sequence of amino acids in a polypeptide chain
- determined by the genes
- can be sequenced in a lab
- determines final structure
- Secondary Structure: Regula repeated coiling or folding of the helix or pleats in a polypeptide chain
- stabilized by hydrogen bonds
- protein's backbone
- Tertiary Structure: 3 dimensional large folding of the polypeptide chain
- 2 types of bonds= weak interactions and covalent linkages
- Quaternary Structure: structure that results from interactions between several polypeptide chains
- fibrous/globular proteins
- all proteins do not have quaternary
Outline the difference between fibrous and globular proteins, with reference to two examples of each protein type.
Fibrous: Secondary structure is dominant (determines overall structure), long and thin, insoluble in water
- Ex) Collagen, spiders silk
- Globular: tertiary or quaternary structures are dominant, folding into round shapes
- soluble in water
- ex) hemoglobin, amylase
Explain the effects of temperature, pH, and substrate concentration of enzyme activity
TemperatureEnzyme reaction rate increases with increasing temperature. Optimal temperature allows for the greatest number of molecular collisions without denaturing the enzyme. Beyond optimal temperature, reaction rate slows due to denaturation.
- pHFor an enzyme to be effective, it must have a certain shape so the substrate can fit into it. The pH of the system that an enzyme is found in can influence the folding of the polypeptide chains of the proteins, and the shape. As the pH increases or decreases from its optimum, enzyme activity is reduced.
- Substrate ConcentrationIn general, the greater the substrate concentration, the faster the reaction. This is because the chance that a substrate will encounter the correct active site increases. Reaction rate levels off after awhile, because the active sites saturate
State three functions of lipids
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