Module 2: Molecules of Life Flashcards
Each Atom contains…
- Protons
- neutrons
- electrons
– move around in orbitals (two per orbital), grouped into shell
Atoms combine with other atoms to form
molecules
covalent bonds
sharing electron
- polar if unequal sharing
- nonpolar of equal sharing
Universal solvent
water
hydrogen bond
weak bond formed between EN atom and hydrogen atom thats already covalently linked to another atom
hydrophilic
water loving
hydrophobic
water fearing
pH
- measurement of concentration of protons (H+) in a solution
- ranges from 0-14
- > 7 acidic
- <7 basic
Organic molecules
molecules that contain carbon
Polymers
repeating of a structure (monomer) (like sugar repeating a bunch)
4 types of biological molecules
- Proteins
- provide structural support and act as catalysts - Nucleic acids
- encode and transmit genetic information - Carbohydrates
- provide structural support for many organisms and source of energy - Lipids
- make up cell membranes, store energy, important in cell communication
Macromolecules
- large molecules that are built from smaller organic molecules
Condensation
- reaction
- requires energy
- makes a chain and a water
Hydrolysis
- reaction
- releases energy
- breaks the chain with a water
Functional groups
- addition of functional groups changes the chemical character to carbon chains
- have chemical properties of their own
- typically involved in reactions that combine simpler molecules to form polymers
- N, P, O, S more EN, form polar functional groups
- methyl groups form nonpolar
Functions of Proteins
- act as enzymes
-aid in transport - role in cell signaling/ regulation
- movement
- support
- defense
Amino Acid Structure
- proteins consist of amino acids that are covalently linked into linear polymers (aka polypeptides)
STRUCTURE - central carbon is covalently linked to 4 groups
– carboxyl (-COOH)
– amino (-NH2)
– hydrogen (H)
– R group (side chain, distinguishes one amino acid form another)
Joining amino acids
- amino acids have both positive and negative charges (amino group +, carboxyl group -)
- a zwitterion
- joined by covalent bond (peptide bond)
- when peptide bonds form, the carboxyl group releases an oxygen atom, and the nitrogen atom loses two H atoms to produce H2O
- theres 20 genetically encoded amino acid monomers
– order provides information carried out by protein - somtimes 2 or more polypeptide chains must combine to form a mature protein
Nucleic acids are…
information molecules
- encode genetic information in the sequence of nucleotides
2 types of nucleic acids
DNA
- genetic material in all cellular organisms
- contains information used to direct protein synthesis
RNA
- multiple functions, key player in protein synthesis and regulation of gene expression
Nucleotides
DNA and RNA are polymers of nucleotides, which are composed of:
1. Nitrogen containing base
- one of two types:
– Pyrimidine base that contains a single ring (C,T,U)
– Purine base that contains double ring (A,G)
2. 5-carbon (pentose) sugar
- in DNA, Deoxyribose
- in RNA, Ribose
3. one or more phosphate group
Nitrogenous bases
DNA uses ATGC
RNA uses AUGC
- order of the bases determines the information carried
Cytosine
YELLOW
Single ring
NH2
Thymine
BLUE
single ring
CH3, O =
*only DNA
Uracil
GREEN
single ring
O=
*only RNA
Guanine
RED
double ring
O=
Adenine
PURPLE
double ring
NH2
Nucleoside
Just base and sugar
Nucleotide Functions
- Monomers of DNA and RNA
- important signal molecules within cell
- transfer energy in metabolism (cleave off terminal phosphate group to release stored energy)
- ATP -> ADP + Pi + Energy
- act as coenzyme /cofactors
- typically adenine containing nucleotides combined with B vitamins
Connecting Nucleotides
- covalent linkage btwn phosphate group of one nucleotide sugar to the sugar unit 3’-OH on another
- FORMS phosphodiester bond
- formation releases water
- formation of bond also establishes directionality/ polarity of strand
- beginning of strand 5’ end
- new nucleotides added to 3’ end
- chain always built 5’ to 3’
DNA structure
- consists of two strands of nucleotides twisted around each other in a double helix
- sugar phosphate backbone wrap around outside
- antiparallel
- complementary bases face inwards with hydrogen bonds forming between bases
– make it easy to break apart and rebuild - 3 H bonds between C-G
- 2 H bonds between A-T
Carbohydrates made up of…
C, H, O atoms
- usually in a ratio of 1:2:1
Carbs serve as…
major source of energy for metabolism
- also serve as structural molecules
Simplest carbs are…
saccharides (single sugar)
- contain 5 or 6 carbon atoms (can be linear or cyclic)
6-Carbon Sugars
- all have same chemical formula of C6H12O6
-differ in configuration, they’re isomers, so functionally different - simple sugars, monosaccharides
Glucose
Aldose sugar ( has aldehyde group, H- C=O at end with C bonded to another carbon)
- Has one OH on wrong side
Galactose
Aldose sugar ( has aldehyde group, H- C=O at end with C bonded to another carbon)
- Has two OH on wrong side
Fructose
Ketose sugar (has ketone group, C=O)
In cells virtually all monosaccharides are…
in cyclic form
Cyclic Monosaccharides
- cyclic forms from one end of linear molecule bind to another part of chain
- carbon in aldehyde or ketone groups form covalent bond with oxygen of hydroxyl group
Linking Sugars
- covalent linkage between monosaccharides is a glycosidic bond
- formation of the bonds releases water molecule
- forms between C1 of one monosaccharide and OH group on different carbon of monosaccharide
Covalently linking two monosaccharides…
forms a disaccharide
A few monosaccharides joining forms a
oligosaccharide
- can be attached to:
– protein forming -> glycoproteins
– lipids forming -> glycolipids
thousands of monosaccharides…
polysaccharide
Lipids are a chemically diverse group of molecules because…
only macromolecule that is not a polymer
Lipids all share the same physical property…
hydrophobic
Cells use lipids in the following ways…
- Triacylglycerol (used for energy storage)
- Steroids (found in animal cell membranes, precursor to steroid hormones)
- Phospholipids (major component of biological membranes)
Triacylglycerol
- major component of animal fat and vegetable oil
- Made up of:
1. Three fatty acids (type of lipid made up of long chain of carbons attached to a carboxyl group [-COOH] at one end)
– no double bonds between the carbon atoms, SATURATED
– has carbon carbon double bond, UNSATURATED
2. Glycerol, a 3 carbon molecule with OH groups attached to each carbon
Steroids
- composed of many carbon atoms bonded to characteristic four fused rings
- hydrophobic
- cholesterol is a component of animal cell membranes
cholesterol can also serve as precursor to steroid hormone synthesis
Phospholipids
- Major component of cell membranes
- made up of
1. Glycerol backbone attached to a polar phosphate group (hydrophilic)
2. Two fatty acid tails which are nonpolar
(hydrophobic)
Molecules with both hydrophilic and hydrophobic regions are called…
Amphipathic
