LECTURE 2 & 3 Flashcards
The formation of covalent bonds results in an
arrangement of orbitals in the valence shell.
Weak chemical bonds:
these interactions can be reversible, or modified to the molecule.
Van der waals interactions
Because of random positioning of the electrons in the orbitals, net displacements can occur, creating brief charge differences. This dynamic charge distribution allows molecules to stick to each other if they are very close. Different molecules exhibit different “stickiness” depending on the arrangement of respective atoms.
The formation of covalent bonds results in
Rearrangement of orbitals in the valence shell.
The change in _______ forms the bond
Charge
Weak chemical bonds are
Are reversible and modified by changes.
The four properties of polar water molecules
1) cohesion of water molecules
2) moderation of temperature by water
- heat of vaporization
- Ava-oration cooling: as water evaporates from surface, remaining liquid cools.
3) water (solids) is less dense then water (liquid)
4) water is important solvent
- hydrophilic
- hydrophobic
The three types of isomers
1) structural isomers
2) geometric isomers
3) enantiomers
Structural isomers
Can have a different bond order of atoms
Geometric isomers
Cis VS trans isomers
Enantiomers
When 4 different atoms ( groups or atoms) bond to carbon, an asymmetric arrangement occurs.
How do you know if something is an Enantiomer?
If the two molecules are mirror images, and cannot be superimposed on each other, they are enantiomers.
Macromolecules
Large molecules that make up living cells
The four types of macromolecules
- carbohydrates
- proteins
- nuclei acids
- lipids
All of which are polymers
Polymers form via ___________. And how?
Dehydration reactions (removing water, forming bonds)
They form by attaching through the formation of a covalent bond and removing the water.
How are. Polymers disassembled
Through hydrolysis (adds water into molecule, breaking bonds)
Adding different monomers together allows for the
Formation of polymers with distinct properties
Carbohydrates
Monosaccharides (one sugar)
- added together to build disaccharides and polysaccharides
Monosaccharides with 3 carbons
Glyceraldehyde
Monosaccharides with 5 carbons
Ribose
Monosaccharides with 6 carbons
Glucose, galactose, fructose
How do cells extract every from glucose (monosaccharides)
Via cellular respiration.
The carbon form sugars that are broken down can be
Reused to form other molecules
Polysaccharides can be sued for
- carbohydrate storage
- structural purposes
Disaccharide
Fros when a dehydration reaction joins two monosaccrhides
Types of Storage polysaccharides
1) starch (amylopectin)
2) glycogen
Starch
Glucose polymers, each monomer joined via 1-4 glycosidic linkages (alpha configuration)
Amylopectin
(Branched Starch)
Branches via alpha 1-6 linkages.
Amylose
Starch that is unchanged and helical.
Glycogen
Animal store glucose in THIS polysaccharides form, which is structurally similar to amylopectin, BUT more branches
Steroids
- they are lipids
- carbons skeleton consisting of four rings.
( EXAMPLE: cholesterol )
Cholesterol
Component in animal membranes
- provides strength and flexibility to animal membranes.
Proteins
- proteins are polymers of amino acids
Amino acids
Amino acids can exist as different enantiomers, but all proteins use L=enantiomers
Polar side chains
- glycine
- alanine
- valine
- Leucine
- isoleucine
- methionine
- phenylalanine
- tryptophan
- proline
(ALL OF THEM HYDROPHOBIC)
Polar side chains ROPHILIC
- Serine
- Threonine
- Cysteine
- Tyrosine
- Asparagine
- Glutamine
ALL OF THEM HYDROPHILIC
Electrically charged
1) acidic (negativity charged)
2) basic (positively charged)
Acidic (negatively charged)
- aspartic acid (Astarte)
- Glutamic acid (glutamate)
Basic (positively charged)
- lysine
- arginine
- histidine
Amino acids are linked by
Peptide bonds
A polypeptide is a polymer of
Amino acids
Flour levels of protein structure
- primary
- secondary
- tertiary
- quaternary
Primary structure
The linear sequence of amino acids.
Structure is determined by inherited genetic information.
Poolypetides have an
NH3 (amino) end, and a COO- (carboxyl) end
Secondary
Formation of a-helixes or B-pleated sheets due to hydrogen bonding between O of carbonyl group and the H of the amino group.
When do B-pleated sheets form
When peptide sequence lie next to each other in antiparallel orientation.
Tertiary
The arrangement of the peptide chain due to interactions between R groups, that gives the protein it’s distinctive shape.
(Transthyretin polypeptide)
Quaternary
Results from the aggregation of two or more polypeptide subunits.
(Transthyretin & hemoglobin)
Desaturation
Loss of proteins native structure
A denatured protein is
Biologically inactive.
Diseases caused by misfolded proteins
- Alzheimer’s
- Parkinson’s
- mad cow
Chaperonins
Proteins that assist proper folding of other proteins
Steps of chaperonin actions
1) an unfolded polypeptide enters the cylinder from one end
2) the cap attaches, casing cylinder to change shape in such way that it creates a hydrophilic environment for the fouling of the polypeptide.
3) the cap comes off, properly folded protein emerges.
Can a protein function if not properly folded?
NOO
Nuclei acids
Coded information that cells transmit to further generations and determine protein production
Two types of cyclic acids
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
Polynucleotide made of
monomers called nucleotides
Nucleotides consist of 3 different molecules joined together
- phosphate
- 5 carbon sugar
- nitrogenous base
(Nucleoside and nucleotide)
RNA sugar is
Ribose
DNA sugar is
Deoxyribose
Features of a nucleotide
- 1’ C : attaches to the base
- 2’ C: OH in RNA “two prime OH”
2’ C: H in DNA - 3’C: OH important for polymer formation: “three-prime OH”
- 5’ C: attaches to phosphate group “five-prime phosphate”
To types of nitrogenous bases
Pyramidines and purines
Pyrimidines
- cytosine
- thymine
- Urical
Purines
- adenine
- guanine
Nucleotide monomers can be added together to form ______ ____ polymers via …
Nucleic acids … dehydration reaction
When nucleotide monomers are added,
Nucleotide triphosphate is added, and two phosphates are removed when it gets added.
What’s the backbone of DNA made of
Sugar-phosphate
Phosphate groups is at the ___ end and OH group is at the ___ end
5’ and 3’
Linkage between nucleotides is a
Phosphodiester linkage
RNA molecules are usually a
Single polynucleotide chain
Base pairing can happen between RNA and …
- DNA
- other RNA’s
- itself
Nucleotide acids
DNA and mRNA
MRNA
(Messenger RNA) transmits information within the cell.
