Ch 2 Flashcards
Aseptic technique
Set of practices and procedures used to prevent contamination from pathogen. Is used when transferring bacteria from one place to another without contaminating ourselves or environment
Spectrophotometer
Measures the amount of light transmitted or absorbed directly through a sample OR it measures the turbidity of a sample to estimate cell number
Turbidity
Cloudiness
Properties of water
65% of our bodies are water
Polar molecules (dipole)
Excellent solvent
Hydrogen bonding
Water acts as a temperature buffer
Can act as a base or acid in chemical reactions
Water as a polar molecule
Polar nature makes water an excellent solvent.
Dissolves polar and charged molecules
These compounds are hydrophilic
Water with dissolved substances freeze at a lower temperature
Cohesion
Due to polar nature water molecules stick to other water molecules
Adhesion
Water molecules stick to other materials due to its polar nature
Surface tension
Creates the skin-like surface formed due to the polar nature of water
Ph
The concentration of H+ in a solution
Acid
Releases H+ . Proton (H+) donor
Base
Releases OH- proton (H+) acceptor
Acidic scale
0 = most acidic. 14= most basic. 7 = neutral
Ph of aqueous solutions
Pure water has equal concentrations of each so its neutral
Each log unit represents ten-fold change in [H+]
Buffer stabilizes (keep in defined range) ph of solution
Most cells like to grow in neutral ph
4 major classes of organic molecules
Carbohydrates: monomer of monosaccharide
Lipid: monomer are fatty acids
& glycerol
Proteins: monomers are amino acids
Nucleic acids: monomers are nucloticles
What is a monomer?
Individual subunit that make up polymers or macromoteches
Carbohydrates
Diverse group includes sugars & starches
Energy source, energy storage
Carbon source
Component of DNA RNA
Structural component of cell
Lipids
Lipids are non polar, hydrophobic molecules, made of heterogenous group of compounds, mainly composed of hydrocarbon chains
Energy storage (for long use)
Cell membrane
Hormones
Lipid monomer
Fatty acids & glycerol
Bacteria in our gut makes short chain fatty acid chains that feed intestinal wall cells
Phospholipids
Very important part of cell membrane
Protects the cell from the outside environment. Selective permeability
Structure of phospholipids
Phosphate group linked to polar molecule hydrophilic head, Hydrophobic fatty acid tails. Form lipid belayer
Essential component of cytoplasmic membrane
Triglycerides
Common fats found in our body
Glycerol linked to fatty acids via dehydration synthesis
Fatty acids are chains of bonded C,H atoms with carboxyl group at one end
Saturated fats vs unsaturated fats vs trans fats
Sat. No double bonds
Unsaturated- trans: h atoms opposite
(hard to break down)
Unsaturated-cis: bent ( naturally occurring)
Proteins
Most common organic molecule
Composed of amino acids
Function of proteins
Enzyme are catalyst
Transport
Provide mechanical support
Generate mechanical support
Generate movement/motility
Cell receptors
Regulation of gene expressions
Amino acids
20 amino acids, protein characteristics depend mainly on shape(determined by amino acid sequence )
Amino acid structure
Central carbon, carboxyl group, amino group, side r-group
Peptic bonds
Hold amino acids together
Covalent bonds formed by reaction between carboxyl + amino
Dehydration synthesis
Protein structure
Proteins are one or more long polypeptide folded to create functions modules
Protein structure levels
Primary: sequence of amino acids
Secondary: hydrogen bonds & beta sheets chain folding
Tertiary: 3D shape of protein
Quaternary: 2 or more polypepticle
Folded proteins vs denatured protein
Fp: Specific function & domains
Dp: loss of function no domain
How proteins denature
High temperature, extreme ph, solvents an break bonds
DNA vs RNA
D: genetic information found in cell or genes, double stranded,deoxyribose,ATGC, strands are antiparallel ( 5’ to 3’) strands are complementary
R: RNA is made from DNA, single stranded, RNA synthesizes proteins, many types ( mRNA, tRNA, tRNA ) ribose,AUCG
DNA is eukaryotes vs prokaryotes
Eukaryotes: found in nucleus 46 chromosomes
Prokaryotes: found in cytoplasm of cell in region called nucleoid 1 circular chromosome
mRNA, tRNA, tRNA
Messenger RNA carries DNA to ribosomes
Transfer RNA transfers amino acids to ribosomes
Ribosomal RNA makes up ribosome - protein factories of the cell
The role of ATP
Adenosine triphosphate
ATP → adp+pi
3 negatively charged phosphate groups repel
Bonds unstable easily broken
Releases energy to drive cellular process
High energy phosphate bonds denoted by -
