Biology Chapter 2: Molecular Biology

organic compounds

Compounds that contain carbon

inorganic compounds

Compounds that do not contain carbon

Macromolecules

carbohydrates, lipids, proteins, nucleic acids

Metabolism

the chemical processes that occur within a living organism in order to maintain life.

Anabolism

Constructive metabolism; the process of building up larger molecules from smaller ones.

Catabolism

The sum total of all processes in an organism which break down chemicals to produce energy and simple chemical building blocks.

hydrolysis reaction

A chemical reaction that breaks apart a larger molecule by adding a molecule of water

condensation reaction

A reaction in which two molecules become covalently bonded to each other through the loss of a small molecule, usually water; also called dehydration reaction.

Urea

major nitrogenous waste excreted in urine

polarity of water

water is a polar molecule meaning it has opposite charges on opposite ends. This causes hydrogen bonds to form causing water to stick together.

Hydrophobic

Having an aversion to water; tending to coalesce and form droplets in water.

Hydrophilic

Attracted to water

Cohesion

Attraction between molecules of the same substance, like water

surface tension

the force that acts on the surface of a liquid and that tends to minimize the area of the surface

Adhesion

An attraction between molecules of different substances

capillary action

the combined force of attraction among water molecules and with the molecules of surrounding materials

Thermal properties of water

High specific heat capacity, High latent heat of vaporization, High boiling point

High specific heat capacity

it takes a lot of heat to change the temperature of water

specific heat

The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree celcius

coolant

a liquid or gas that is used to remove heat from something

high latent heat of vaporisation

takes alot of energy to break the hydrogen bonds between water molecules - so lot's of energy is used up when H2O evaporates - useful for living organisms as they can used water loss through evaporation to cool without losing too much

latent heat of vaporisation

The heat energy needed to change the substance from a liquid at its boiling point into gas at the same temperature.

Solvent

A liquid substance capable of dissolving other substances

Glucose

the form of sugar that circulates in the blood and provides the major source of energy for body tissues. When its level is low, we feel hunger.

amino acids

monomers of proteins

Fats

lipids that are solid at room temperature

Cholesterol

A lipid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids.

Oxygen

gas that enters the blood through the lungs and travels to the heart to be pumped via arteries to all body cells

Sodium Chloride

compound

Methane vs. Water

methane molecules are nonpolar, do not form H-bonds with each other, so much smaller range of tempertures in liquid state, much less energy required for evaporation; specific heat capacitity is 1/2 that of water.

Carbohydrates

Broken down to glucose to provide energy.

Monosaccharides

Single sugar molecules

disaccharides

Carbohydrates that are made up of two monosaccharides

Polysaccharides

Carbohydrates that are made up of more than two monosaccharides. Can't be dissolved in water

Polymerisation reaction

reaction in which a large number of small molecules react together to form one very large molecule

hydroxyl group

OH-

glycosidic bond

A glycosidic bond is a covalent bond in which a carbohydrate binds to another group, which could also be a carbohydrate. A glycosidic bond is found between the two glucose molecules in maltose.

D-glucose and L-glucose are

Enantiomers

The only enantiomer for any D-sugar is it's L-sugar counter part

Types of monosaccharides

glucose, fructose, galactose

types of disaccharides

sucrose, lactose, maltose

types of polysaccharides

starch, glycogen, cellulose, chitin

Cellulose

Carbohydrate component of plant cell walls.

Glycogen

Storage form of glucose

Starch

storage form of glucose in plants

Chitin

Polysaccharide found in arthropod exoskeletons and fungal cell walls.

amylose and amylopectin

two types of starch

Lipids

Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen.

Glycerol

A three-carbon alcohol to which fatty acids are covalently bonded to make fats and oils.

Triglycerides

an energy-rich compound made up of a single molecule of glycerol and three molecules of fatty acid.

saturated fatty acid

A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms that can attach to the carbon skeleton.

unsaturated fatty acid

A fatty acid possessing one or more double bonds between the carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.

Monounsaturated

an unsaturated molecule that contains only one double or triple bond in the carbon chain.

polyunsaturated

a type of molecule that contains more than one double or triple bond in the carbon chain.

cis fatty acids vs. trans fatty acids

cis - hydrogens on same side of the double bond, U formation. most are unsaturated acids

trans - hydrogens on opposite sides of double bond. linear

Cis fats vs Trans fats

Cis fats are the typical form of unsaturated fat found in nature, while trans fats are made through hydrogenation. Trans fats have a higher melting point. Trans fats promote bad cholesterol while cis fats promote good cholesterol

Phospholipids

a lipid consisting of a glycerol bound to two fatty acids and a phosphate group.

Steroids

lipids characterized by a carbon skeleton consisting of four fused rings

Good fatty acids

Omega- 3 fats:

flaxseed oil and fish oil; cannot be made by humans; obtained in diet

-polyunsaturated; positive effects on cardiovascular health

Bad fatty acids

Saturated Fats- Animal fats; also in palm and coconut oils

Overconsumption associated with increased cardiac disease risk

properties of lipids

hydrophobic, non-polar, high energy, less dense than water, good insulation

effects of saturated fats

obesity, diabetes, coronary heart disease, and some cancers

Body Mass Index (BMI)

A measure of body fat that is the ratio of the weight of the body in kilograms to the square of its height in meters.

Polypeptides

long chains of amino acids

R group

a functional group that defines a particular amino acid and gives it special properties.

Conformation of a protein

the spatial arrangement of atoms in a protein or any part of a protein

primary structure of protein

the amino acid sequence of the polypeptide chain

secondary structure of protein

The way in which the chain of amino acids of the polypeptides of a protein is folded.

tertiary structure of protein

protein structure is formed when the twists and folds of the secondary structure fold again to from a larger 3D structure

quatrenary structure of protein

proteins made up of two or more polypeptide chains

Proteome

the entire set of proteins expressed by a given cell or group of cells

globular proteins

spherical, water-soluble proteins.

fibrous proteins

long, insoluble, structural proteins.

Helicase

An enzyme that untwists the double helix of DNA at the replication forks.

DNA polymerase

Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule

Meselson-Stahl Experiment

Used isotope of nitrogen to change the weight of DNA N15 & N14, demonstrated that the semi-conservative model is the best description of replication.

Adenine

The base that pairs with Thymine in DNA

Guanine

The base that pairs with Cytosine in DNA

Thymine

the nucleotide that hydrogen bonds with the nucleotide adenine in DNA.

Cytosine

The base that pairs with Guanine with DNA

Uracil

Nitrogen base that pairs with adenine in RNA.

RNA polymerase

Enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription

antisense strand

the strand of DNA that runs 3' to 5' and is complementary to the sense strand. It acts as a template strand during transcription.

mRNA

A type of RNA, synthesized from DNA, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein.

Codon

A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid

Nucleotide

monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

tRNA

transfer RNA; type of RNA that carries amino acids to the ribosome

PCR (polymerase chain reaction)

A laboratory technique for amplifying DNA in vitro by incubating with special primers, DNA polymerase molecules, and nucleotides.

Taq polymerase

A DNA synthesis enzyme that can withstand the high temperatures of PCR

transgenic organism

organism that is genetically engineered by inserting a gene from another organism

Plasmid

A small ring of DNA that carries accessory genes separate from those of the bacterial chromosome

Insulin

A hormone produced by the pancreas or taken as a medication by many diabetics. Regulates metabolism