MODULE 1 Flashcards
Carbon
- inherently neutral (uncharged)
- non-polar/hydrophobic
O, N, P (sometimes S)
make compounds
* polar/hydrophilic
* partly (dipoles) or fully charged (i.e. molecules with those atoms/colours will be polar)
Covalent bond
holds molecules together
Eukaryote
organism has cells with a defined nucleus (can be single celled or multicellular)
Prokaryotic
single celled organism without a nucleus
Main molecules types in bio
- Water
- Carbs
- Lipids
- Amino acids
- Nucelotides
Water…
- Stabilise temp
- Ice floats (insulate water/floating platforms)
- Water tensions (H bonding)/capillary action
- Good solvent for polar molecules
- Poor solvent of hydrophobic molecules (cell membranes)
Monosaccharides
Usually form rings
* Glucose (6 atom ring)
* Fructose
* Galactose
* Ribose (5 atom ring)
Carbs/sugars/saccharides
Composed of C,H,O with general formula Cn(H2O)n
* ‘n’ # of carbon atoms
* Lots of O = very polar
Disaccharides
2 mono joined together
* Lots of different connections
* Lactose
* Sucrose
* Trehalose (glucose/glucose)
Sugar polymers
Long chains of mono
* Starch - Storage
* Chitin - Protection
* Cellulose - Structure
Saturated lipid
all single bonds
Liquid typically
Unsaturated lipids
one or more double bonds
Solids typically
triglycerols
Energy stores
* Adipocyte (fat deposit)
steroids
Signalling molecules
Lipid
Phospholipids
Form cell membranes
* Mostly H-phobic but with polar end
* Polar parts interact with aq enviro, H-phobic parts cluster together
* Lipid bilayers separate inside + outside cell
amino acids
Building blocks of protein
In aq sol. the amino and acid group…
Are charged (NH3+ and COO-)
* This is the NORMAL STATE for amino acids in nature
Nucleotides
- Phosphate group (-ve charge)
- Sugar (ribose or deoxyribose)
- Nucleobase (A,G,C,T,U)
Mono/di/tri-nucleotides
dAMP (mono)
dADP (di)
dATP (tri)
Capillary action
ability of liquid to flow in narrow spaces, even against gravity
Purine
- double ring, flat aromatic base (A, G)
Pyrimidine
- single ring flat aromatic base (C, T, U)
5’ to 3’
Nucleic acids
N-terminus (or amino terminus) to C-terminus (or carboxy terminus)
Proteins
Residues
Some of monomer is lost on polymerisation, leaving residue incorporated in the growing chain
* For these molecules, the residue is usually the biggest part
Biopolymer synthesis relies on…
dehydration reactions and are anabolic
Common sugar phosphate backbone
- Negative charge on phosphates
- Hydrophilic (sugars and phosphates)
- 5’ and 3’ ends
Things in DNA vs. RNA
Deoxyribose (DNA)
Ribose (RNA)
Uracil (RNA)
Thymine (DNA)
Electrophoresis
Nucleic acids migrate in an electric field because they are charged.
* Distance they migrate dependent on size
<50 amino acid residues
NB peptides
> 50 residues
protein
Aromatic protein side chains and nucleobases have a characteristic absorbance…
~280 nm (proteins) or ~260 nm (bases)
Record spectra
A260:A280 PROTEINS
A260:A230 CARBS/PHENOL
C and G complement
3 hydrogen bonds
stronger
A and T complement
2 hydrogen bonds
A bit weaker
beta DNA
- Strands run in opposite directions
- Flat bases stack on top of one another (reduced A260nm intensity)
- Negative phosphates repel each other
- Right handed double helix
- Major and minor grooves
N-glycosidic bond
covalent bond between sugar and base in RNA/DNA
Phosphodiester bond
covalent bond between nucleotides in RNA/DNA
Deamination
loss of an amine
dsDNA
double stranded DNA
ssDNA
single stranded DNA
Tm/Melting point
when 50% of the molecule is unfolded/separated
Information flow
Going from DNA >transcription> RNA >translation> PROTEINS
Genome
Complete genetic information
DNA
Transcriptome
all the RNA expressed in a cell/tissue at a give time
Proteome
all the proteins expressed in a cell/tissue at a give time
Prokaryotes have ____ genomes
Small
* Bacteria and archaea have circular chromosomes (plasmids)
Eukaryotes have ____ genomes
Big
* Linear chromosomes
* Condensed into chromatin
* Wrapped around histone protein
mRNA
message for making proteins
* Often multiple copies made, designed to be used then degraded
MicroRNA and snRNA
regulatory roles
Ribosomal RNA & Transfer RNA
Important for protein synthesis
role of proteins
shape, they form receptors, enzymes, hormones and growth factors, toxins, transporters and antibodies
Epigenetic regulation
Expression of some genes is altered by chemical modifications of DNA and proteins but NOT to the DNA sequence itself - epigenetics.
* Can be passed through generations of cells (and individuals)