Topic 2: Molecular Biology (2.1-2.4)

molecular biology

molecular biology

the study of explaining life processes in terms of the chemical substances involves

list the four main elements found in organic compounds

• hydrogen

• oxygen

• nitrogen

• carbon

HONC!

explain the importance of carbon

• all living things are composed of organic compounds, compounds containing carbon

• carbon has 4 electrons on its outer ring, allowing 4 bonds to be created

covalent bonds

• the bonds that hold two or more atoms together by sharing electrons

• can be single, double, or triple

• relatively strong

intermolecular forces

• relatively weaker bonds that hold molecules together

hydrogen bond

• an intermolecular bond that can form between the positive pole of one water molecule to the negative pole of another

  • the bond between one, slightly positive, hydrogen atom of a water molecule to the, slightly negative, oxygen atom of another water molecule

polarity

• the consequence of the nucleus of one atom being attracted to the electrons of another

• part of the molecule will have a slight positive charge and another part has a slight negative charge

explain polarity in a water molecule

• the hydrogen nuclei are less attracted to electrons oxygen

• the two hydrogen atoms have a slight positive charge

• the oxygen atom has a slight negative charge

metabolism

all enzyme-catalyzed reactions in a cell or organism; it is a function of life

anabolism

the synthesis of complex molecules from simpler molecules; involves condensation reactions

catabolism

the breakdown of complex molecules into simpler molecules; involves hydrolysis reactions

macromolecules

large molecules

monomers

the building blocks of macromolecules

polymer

a chain of monomers

explain the thermal properties of water

• ice melts at a higher temperature (0 degrees Celsius); heat is needed to stop h-bonds from preventing the movement of water molecules

• water has a high boiling point (100 degrees Celsius)

• water has a high heat capacity

• water has a much higher heat of vaporization

hydrophilic

• substances attracted to water

• form intermolecular bonds with water

• ionic compounds + substances with polar molecules

  • most dissolve as their electrons are more attracted to those of water rather than each other

• soluble

hydrophobic

• substances ‘repelled’ by water

  • it’s just because the hydrophobic substance is more strongly attracted to each other

• insoluble

what property of water demonstrates the strength of h-bonds?

• adhesive property

  • molecules will stick to other surfaces

• cohesive property

  • molecules will stick to each other

as shown through capillary action in xylem vessels

what are the four main classes of large biological molecules that life is based on?

1. carbohydrates

2. lipids

3. nucleic acids

4. proteins

which of life’s organic compounds are polymers?

1. carbohydrates

2. proteins

3. nucleic acids

NOT LIPIDS!

carbohydrates

sugars and the polymers of sugars

what are the monomers of carbohydrates?

monosaccharides

give two examples of monosaccharides and draw their molecular structure

• glucose

  • hexose (6-carbon) sugar

  • C6H12O6

• ribose

  • pentose (5-carbon) sugar

  • C5H10O5

give an example and function of one of each type of saccharide (-mono, -di, -poly)

• monosaccharide

  • glucose: used in cell respiration

• disaccharide

  • lactose: easily broken down and digested

• polysaccharide

  • glycogen: stored in the liver to be used in low blood glucose conc.

what type of bond is created during condensation of two saccharides to form a disaccharide?

glycosidic bond

lipids

insoluble compounds identified by their hydrocarbon chains; there are three types

what are the three types of lipids?

1. triglycerides

2. phospholipids

3. steroids

triglycerides

• contain three fatty acids and one glycerol

• synthesized through condensation reactions creating ester linkages

  • includes fats and oils

phospholipids

• contain a hydrophilic head and hydrophobic tails

• essential components of cell membranes; create the bilayer

steroids

• composed of four fused rings of carbons

  • functional groups can be attached to change the function

list the types of fatty acids

• saturated: all are connected by single covalent bonds

• unsaturated: contains one or more double bonds between atoms in the chain

  • monounsaturated: contains only one double bond

  • polyunsaturated: contains two or more double bonds

proteins

what are the six main functions of proteins?

1. transport

2. enzymatic activity

3. signal transduction

4. cell-cell recognition

5. intercellular joining

6. attachment to the cytoskeleton and extracellular matrix

what are the monomers of proteins?

amino acids

identify the three component groups that make up an amino acid

1. R group

2. Carboxylic group (-COOH)

3. Amino group (-NH2)

along with the carbon and hydrogen atom

what are the four structures of a protein?

1. primary: single polypeptide chain

2. secondary: coils and folds of a polypeptide chain held together by different types of bonds

3. tertiary: 3D shape is created as bonds form between R groups

4. quaternary: interaction between multiple protein subunits.

enzymes

biological catalysts; proteins that help speed up reactions by lowering activation energy needed to kickstart a reaction