Chapter 2: Molecular Biology Flashcards
Organic Chemistry
chemistry of carbon compounds
Anabolism
Building complex molecules from simpler ones. Ex: photosynthesis
Catabolism
Breaking down organic molecules to release energy. Ex: cellular respiration
4 groups of molecules
-carbohydrates, lipids, proteins, nucleic acids
Insulin
protein hormone that facilitates the movement of glucose from the bloodstream to the interior of cells.
examples of carbohydrates
- Monosaccharides (glucose, galactose, fructose, ribose)
- Disaccharides (maltose, lactose, sucrose)
- Polysaccharides (starch, glycogen, cellulose, chitin)
Carbohydrate building blocks
Monosaccharides
Lipids building blocks
Glycerol, fatty acids, phosphate groups
Proteins (polypeptides) building blocks
Amino Acids
Nucleic acids building blocks
Nucleotides
examples of proteins
enzymes, antibodies, peptide hormones
examples of lipids
Triglycerides: fat stored in adipose cells
Phospholipids: lipids forming a bilayer in cell membrane
Steroids: some hormones
examples of nucleic acids
deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and adenosine triphosphate (ATP)
What are the factors determining whether a reaction occurs when two molecules collide
- identity of the colliding molecules
- orientation of the colliding molecules (where they hit each other)
- the speed of the molecules when they collide
Enzymes
protein molecules that have a specific shape into which a reactant(s) can fit, at a molecular location called the active site of the enzyme. By having an active site, the enzyme increases the likelihood of a reaction
Examples of reactions in our body
- replication of DNA, in preparation for cell division
- synthesis of RNA, allowing chemical communication between the nucleus and the cytoplasm
- synthesis of proteins, including bonding of one amino acid to another
- cell respiration, with nutrients being converted into ATP
- photosynthesis with light energy being used to create carbohydrates
Example of catabolism and anabolism
when animals eat foods, food is digested into the building blocks (catabolism). After these building blocks are transported to body cells, they are bonded together to form larger molecules once again (anabolism).
Hydrolysing
digesting
Hydrolysis
A reaction involving the breaking of a bond in a molecule using water.
Condensation reaction
A reaction in which two molecules combine to form a larger molecule, producing a small molecule such as H2O as a by-product
Covalent bond
the bond formed by the sharing of a pair of electrons by two atoms.
Hydrogen Bonding
Whenever 2 water molecules are near each other, the positive end of one attracts the negative end of another.
ephemeral hydrogen bonding explains which variety of events
- why water forms into droplets when it is spilt
- why water has a surface tension that allows some organisms to “walk on water”
- how water is able to move as a water “column” in the vascular tissues of plants
Adhesion
attraction between 2 unlikely molecules
Cohesion
The binding together of alike molecules.
Thermal properties of water
- high specific heat, water can absorb or give off a great deal of heat without chaining temperature very much
- high heat of vaporization, water absorbs a great deal of heat when it evaporates
Water solvent properties
A liquid in which substances (or solutes) are dissolved forming a solution. Water is an excellent solvent of other polar molecules
Hydrophilic molecules
molecules that are polar substances, “water loving”
Hydrophobic molecules
non-polar molecules, “water fearing”
Fatty acids
Any of the group of a long chain of hydrocarbon derived from the breakdown of fats (through a process called hydrolysis).
Monomer
a molecule that can be bonded to other identical molecules to form a polymer.
3 most common monosaccharides
- trioses, containing 3 carbons, C3H6O3
- pentoses, containing 5 carbons, C5H10O5
- hexoses, containing 6 carbons, C6H12O6
Monosaccharides formula
CnH2nOn
Functions of Cellulose (a polysaccharide)
Major component of plant cell walls, helps give rigidity/support to plant parts such as roots, stems and leaves
Functions of Starch (a polysaccharide)
Organic products of photosynthesis are stored in plants as starch, typically as starch granules in chloroplasts or in plant storage areas such as roots or root structures
Functions of Glycogen (a polysaccharide)
Animals store excess glucose in this form. Glycogen is stored in the liver and in muscle tissue.
Two subcomponents of starch
Amylose and amylopectin
Fatty acids structure
have a carboxyl group (-COOH) at one end and a methyl group (CH3-) at the other end. In between is a chain of hydrocarbons usually between 11 and 23
Saturated fatty acids
the carbons are carrying as many hydrogen atoms as they can, in other words are saturated with hydrogen atoms. No double bonds.
Monounsaturated fatty acids
If 1 double bond exists in the chain of hydrocarbons, it is no longer saturated, it has 2 empty spaces where hydrogen atoms could be. This unsaturated fatty acid is called monounsaturated.
Polyunsaturated fatty acids
Have at least 2 double bonds in the carbon chain. 2 or more carbons are not carrying the maximum number of hydrogen atoms (2 or more carbons are double bonded to each other).
Hydrogenation
the double bonds are eliminated by adding hydrogen atoms. It straightens out the natural bent shape of unsaturated fatty acids.
Cis fatty acids
Naturally curved fatty acids. (omega-3)
Trans fatty acids
hydrogenated straightened fatty acids, the result of chemical transformation in food-processing factories.
Component molecules of triglyceride lipids
glycerol and 3 fatty acids
Chemical strategies to store molecules in reserve to use for ATP
- storing glucose as the polysaccharide glycogen in liver and muscle tissues
- storing triglyceride lipids within adipose (fat) cells
Glycogen
A branched polymer of glucose that is mainly produced in liver and muscle cells, and functions as secondary long-term energy storage in animal cells.
Why are triglyceride lipids good for storing molecules
- can by hydrolysed into 2 carbon segments that can enter into cell respiration, have twice the energy content per gramme compared with other molecules
- long-term energy storage: insoluble in water and do not upset the osmotic balance if solutions
Body Mass index (BMI)
a number that reflects both the weight and the height of a person
How to calculate BMI
- using a formula, based on either metric or imperial measurements of weight and height (weight kg/ (height m x height m))
- using a graph known as nomogram
- using an online calculator
Formation of polypeptides
- 20 amino acids to synthesize polypeptides
- each polypeptide created under control of a gene
Polypeptide
A polymer of amino acids joined together by peptide bond
Which gene is universal
the genes that code for proteins involved in common cell cell functions (such as the protein components that make up ribosomes as all cells need ribosomes).
Approximate number of active genes in humans
20 000 to 25 000 genes in each of our cells
Amino Acids
The building block of protein in which each is coded for by a codon (A set of three adjacent nucleotides, the building blocks of nucleic acids like DNA and RNA) and linked together through peptide bonds (covalent bond joining amino acids).
Rubisco protein function
the short hand name for the enzyme that catalyses the 1st reaction of the carbon-fixed reactions of photosynthesis