intro to biological molecules Flashcards
how many bonds can carbon form
Carbon (C) is the basis of living material because of its ability to form four bonds with
- other atoms
- and/or wide variety of chemical groups
what form can carbon based molecules come in
simple, chain, or ring
what bounds are present in carbon-based compounds?
- Carbon-based molecules are often large
* Held together by strong covalent bonds
how many sub-atomic particals of protons, neutrons and electrons in carbon?
6 Protons
6 Neutrons
6 Electrons
carbon bonding with flourine
CF4 one F shares one electron, in total carbon shares four of its electrons .
what are the importance of functional groups attached to carbon based compounds.
what occurs when covalent bonds break?
- Clusters of atoms (functional groups) can attach to carbon-based compounds
- Each type of functional group has specific chemical properties
- Cellular chemical reactions often involve functional group transfer (loss or gain)
- Breakage of covalent bonds in carbon-based compounds releases energy
what are te four most important macromolecules
o carbohydrates
o lipids
o proteins
o nucleic acids
what are the polymers of these monomers:
suger
amino acid
nucleotide
- Macromolecules are composed of building blocks or subunits known as monomers
- Monomers join together with covalent bonds to form long chains or macromolecules known as polymers
polysaccharide
proteins
nucleic aciid
how are polymers formed
- Formed by a type of condensation reaction known as dehydration synthesis
- A molecule of water is formed and removed from the reactants joined during the reaction
how is a new covalent bond formed in a condensation reaction.
• Using energy generated by nearby reactions, a new covalent bond forms between the reactants
how is water formed in a condensation reaction?
• H2O is formed from the loss of a hydroxyl group (-OH) from one reactant and a hydrogen (-H) from the other
what is the name of the process that breaks down polymers?
- Polymers are broken down by an opposite process known as hydrolysis
- Bonds between reactants are broken with the addition of a molecule of water H2O
how does hydrolysis release ATP
- The hydroxyl (-OH) group of a water molecule bonds with one reactant, and the hydrogen (-H) bonds to its neighbour
- The energy held in the bond is released and stored in the form of ATP
Digestion of polymers
- Polymers like starch are broken down into smaller sugar units which are easily absorbed across the gut
- This hydrolysis reaction requires help from digestive enzymes
biological molecules consist of which chemicals?
70% water 4% ions and small molecules 2% phospholipids 1% DNA 6% RNA 15% proteins 2% polysaccharides
why is water vital for life?
• Chemical formula H2O
• Water is the most abundant molecule in your body
o 60-95% of fresh mass of living organisms
• Water is the medium in which cellular chemical reactions occur
• Water plays a major role in living systems
o Growth and reproduction
o Hydration, nutrition, hygiene and health
what properties does water have
• Is a universal solvent and transporter
o All body fluids are mostly water
o Aids movement of chemicals during diffusion
• Is a lubricant
o In joints and on tissues
o Moistens epithelial surfaces
o Shock absorber
• Regulates body temperature
o Water requires heat to turn to vapour
o Sweat absorbs heat from the skin when evaporating
what is the structure of water molecule?
- A simple molecule
* One oxygen atom bonded by single covalent bonds to two hydrogen atoms
how much do you need of water
- The body tissues are 62% water
* Need approx 1.5L per day
what does dehydration do to the body
- Dehydration is associated with many conditions, e.g. diarrhoea
- Dehydration can be fatal and must be rapidly treated
- Fluid replacement therapy – oral or IV
capillary refill test on a child to check hydration status
how does polarity arise in water
- The oxygen atom contains eight positively charged protons (+) in its nucleus
- Each hydrogen atom contains only one positively charged proton (+) in their nucleus
- The electron pair shared in each O-H covalent bond is therefore more strongly attracted to the oxygen nucleus than to either of the hydrogen nuclei
- This makes the water molecule polar with a slightly negative pole near the oxygen (-) and a slightly positive pole near the hydrogen (+)
how does hydrogen bonding occur in water
- The + near the hydrogen atoms is attracted to the - near the oxygen atom of a nearby water molecule
- This results in the formation of a hydrogen bond between two water molecules
Why is water a liquid?
- Hydrogen bonds are weak (5% to 10% the strength of covalent bonds) and are easily broken (each lasts only 1/100,000,000,000 of a second)
- Hydrogen bonding creates a fluid as molecules constantly change partners
Water is a Powerful Solvent
- Sodium chloride (salt) is a lattice of sodium (Na+) ions ionically bonded to chloride (Cl-) ions
- The + hydrogens are attracted to the Cl- ions, while the - oxygens are attracted to the Na+ ions
- The lattice pulls apart and the salt dissolves in the water
why is water considered universal solvent?
- All polar (charged) molecules and ions are water soluble because they can form hydrogen bonds with water
- Ions and polar molecules can move/interact freely and take part in cellular chemical reactions
what properties do nonpolar molecules have?
- Nonpolar molecules have no electrical charge and cannot form hydrogen bonds with water
- Nonpolar molecules repel water molecules and are thus hydrophobic whereas polar molecules attract water and are hydrophilic. Some complex molecules have a mixture of both properties and are amphiphilic
- The 3D shape of many biological molecules is influenced by hydrophobic forces
how are alveoli prevented from collapsing
• Surface tension tends to make lung alveoli collapse
• Alveoli
secrete a non-polar ‘surfactant’ to break the surface tension
how does surface tension occur
a. Causes surface layer of liquid to act as an elastic sheet
b. Caused by inter-molecular attractions between water molecules
How surfactant prevents atelectasis in premature babies
c. Lungs create non-polar ‘surfactant’ to break the surface tension in the alveoli. Helps prevents atelectasis in premature babies by prevent the formation of surface tension to occur in alveoli
