Biol 1057 - chemsitry of life Flashcards
Define a chemical bond
Occurs when atoms are held together by forces of attraction
What are biological molecules
- Biological molecules are found in living organisms and are made of atoms
Briefly outline ionic bonding
- Ioinic bond is the electrostatic attraction between oppositely charged ions
- (METAL AND NON METAL - NaCl)
Briefly outline covalent bonding
- Covalent bond is when 2 or more atoms share 1 or more pairs of elections which forms a molecule
( 2 NON METAL - H2 )
Briefly outline why hydrogen bonding happens
OXYGEN IS MORE ELECTRONEGATIVE THEAN HYDROGEN AND ELECTRONS UNEVENLY DISTRIBUTED
O has a slight negative charge(δ-)
H has a slight positive charge(δ+)
- leading to a weak electrostatic attraction (hydrogen bonding)
Outline 2 basic facts about water
- All living organisms are 70-90% H20
- 3/4 of the earth is covered in H20
Outline 2 properties of water due to hydrogen bonding
- Cohesion & surface tenstion between water molecules
= Allows long columns of water to travel in tube-like transport cells of plants - Adhesive
Outline 2 properties of water due to hydrogen bonding
- Good solvent
= Facilitates chemical reactions inside and outside of the body
= Dissolves hydrophillic substances like polar solutes (HYDROPHOBIC CANNOT) - Regulates temperature
= Body temperature regulation - sweating
= Ice is less dense that liquid H2O - ice floats
Describe what is meant by monosaccharides and disaccharides and polysaccharides
M
- Monomers from which larger carbohydrates are made from
Examples -
GLUCOSE
FRUCTOSE
GALACTOSE
D
- Made from condensation 2 monosaccharides forming glycosidic bond
Examples -
MALTOSE = Glucose molecule + Glucose molecule
SUCROSE = Glucose molecule + Fructose molecule
LACTOSE = Glucose molecule + Galactose molecule
P
- Made from the condensation of many glucose units forming glycosidic bonds
Examples -
STARCH = condensation of a-glucose
GLYCOGEN = condensation of a-glucose
CELLULOSE = condensation of b-glucose
Briefly outline Starch, glycogen and cellulose
G
- 1,4 & 1,6 glycosidic bonds so branched
- Condensation of a-glucose
- Main energy store molecule in animals & highly branched to insrease SA for hydrolysis
S
- Main energy store in plants
- Condensation of a-glucose
- amylose 1,4 & amylopectin1,6
C
- 1,4 glycosidic bonds
- Cell walls in plants
- Condensation of b-glucose
- Unbranched straight chains and hydrogen bonds
Structure of glucose(BOTH)
Outline how proteins are made and the structure
- Amino acids are the monomers from which proteins are made
H
NH₂ - C - COOH
R - 20 different amino acids based on R groups
Briefly outline the 2 types of amino acids
- Non-essential amino acids can be synthesized by the human body (11/20)
- Essential amino acids cannotbe synthesized by the human body and must be obtained through the diet (9/20)
Describe the condensation reactions in amino acids.
Dipeptides = Condensation of 2 amino acids to form a peptide bond
(NH2 and carboxyl)
Describe how the structure of a protein depends on the amino acids it contains
- Primary structure is sequence of amino
acids on polypeptide - Secondary structure are α-helices or β-pleated sheets with hydrogen bonds
- Tertiary structure formed by interactions between R groups
- Tertiary structure creates active sites in eznymes - Quaternary structure formed by bonds between more than 1polypeptide chain to form specific 3D shape
Describe what is meant by an enzyme.
- Enzymes are:
➢Highly specific
➢Extremely efficient
➢Subject to cellular controls
Briefly outline enzyme action
- Substrate binds to enzyme at active site to for enzyme substrate complex
- Enzyme catalyses reaction and transforms substrate into products
- After reaction, enzyme remains unchanged
Outline characteristics lipids share
- Hydrophobic = insoluble to water
- Soluble in organic solvents, such as alcohol
- Two main groups – triglycerides (fats & oils) and phospholipids
- They contain carbon, hydrogen and oxygen
Outline the roles of lipids
Source of Energy – more than twice the energy as the same mass of carbohydrates
Waterproofing – prevents water loss
Insulation – slow conductors of heat so they help the body retain heat.
Protection –fat is stored around delicate organs like the kidneys
Describe how the 2 types of lipids are formed
Triglycerides
- Formed by condensation of
1 GLYCEROL MOLECULE & 3 FATTY ACIDS
- Joined by ester bonds & 3 waters released
Phospholipids
- Formed by condensation of
1 GLYCEROL MOLECULE BACKBONE &
2 HYDROPHOBIC FATTY ACID TAILS
Joined by ester bonds
~~~
&= 1 HYDROPHILLIC PHOSPHATE HEAD formed by phosphodiester bond NOT ESTER & NOT CONDENSATION
Describe the difference between saturated and unsaturated fatty acid chains.
Saturated
- Only contains single C-C bonds between carbon atoms
- Higher melting points
Unsaturated
- Contains 1 or more C=C bonds between carbon atoms
- Lower melting points
What are steroids
Steroids - backbone of four fused carbon rings
INCL = cholestrol, testosterone and oestrogen
Describe the structure of a DNA nucleotide.
NUCLEOTIDES ARE THE MONOMERS
- Deoxyribose(Pentose sugar)
- Phosphate group
- Nitrogenous base
ADENINE, THYMINE, CYTOSINE, GUANINE
- form polynucleotide double helix structure
Describe the structure of a RNA nucleotide.
- Ribose(Pentose sugar)
- Phosphate group
- Nitrogenous base
ADENINE, URACIL, CYTOSINE, GUANINE - form single polynucleotide chain
Describe how a polynucleotide strand is formed.
- Condensation reaction between deoxyribose sugar and phosphate group creating a phosphodiester bond
Describe how a DNA molecule is made
- Double helix structure with 2 polynucleotide chains held together by hydrogen bonds
(Between complementary bases)
ADENINE & THYMINE - 2 hydrogen bonds
CYTOSINE & GUANINE - 3 hydrogen bonds
Describe the structure of ATP & reveal the name
- Adenosine Triphosphate
- Nucleotide Derivative & formed from
= a molecule of ribose(PENTAGON)
= a molecule of adenine(RECTANGLE)
= 3 phosphate groups
Describe the function of ATP
- ATP is the principal energy storing molecule in the body
- Energy is released from ATP when the end phosphate is removed, and it becomes ADP (adenosine diphosphate),
which is a low energy molecule
