Unit 1 Terms Flashcards
Lipids
high molecular weight molecules soluble in nonpolar solvents
Proteins
- large biomolecules and macromolecules that comprise one or more long chains of amino acid residues.
- diversity of structures, resulting in a wide range of functions
- everything in a cell is mediated
by proteins - made up of 20 amino acids, which have different physical and chemical properties
Polysaccharides
- long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic bonds.
- storage or structural molecules
Nucleic acids
- DNA and RNA
- Nucleic acids are macromolecules that exist as polymers called polynucleotides. The monomers are called nucleotides.
Triacylglycerols
made up of one Glycerol molecule and 3 fatty acids
Phospholipids
- hydrophilic “head” containing a
phosphate group and two hydrophobic “tails” derived from fatty acids - main components of cell membranes
- addition of R group makes t hydrophilic, allowing mixing of H2O and composing membranes
- Enzymes that metabolize phospholipids are in ALL membranes but never in the cytosol
Amphipathic
having both hydrophilic and hydrophobic parts.
ex: phospholipids
Disaccharides
two monosaccharides joined by a
glycosidic bond.
Cellulose
structural polysaccharide of the cell wall of green plants
Chitin
long-chain polymer of N-acetylglucosamine and the main component of insect exoskeleton
amino acid
- is an organic molecule with both an amino group and a carboxyl group
- side chain varies
- made up proteins
polypeptides & peptide bond
- Polypeptides are Amino Acid Polymers
- peptide bond: covalent bond between amino acids
nucleotide
- is composed of three parts: a
nitrogenous base, a five carbon sugar, and one phosphate group - monomers
pyrimidines vs purines
- nitrogenous bases
- pyrimidines: C, T & U
- purines: A & G
DNA vs RNA
- DNA: Cytosine, Thymine, Adenine ,
and Guanine - RNA: Cytosine, Uracil, Adenine , and Guanine
Three Polymerases
- RNA polymerase I : rRNA genes,
- RNA polymerase II : mRNA, miRNA, snRNA, and snoRNA genes
- RNA polymerase III : tRNA and 5S rRNA genes
Start/stop codons
- The start codon is the first codon of a mRNA transcript translated by a ribosome. Stop codon signals the termination of the translation process
Start codon = methionine
Stop codon = no aa
- There is no stop tRNA but a protein
that stops translation (translation termination factor)
Spliceosomes
cut up the exons and reconnect them to produce the mRNA molecules that are used to make proteins.
Translocases (think membranes & lipids)
proteins that move phospholipids between layers and maintain the lipid asymmetry
FRAP (Fluorescence recovery after photobleaching)
method to study the mobility of molecules in living cells
Crossing membranes (which can/cannot)
Can diffuse freely
- Small uncharged molecules
Can’t diffuse freely
- Large polar molecules
- Charged ions
symporters vs antiporters
(facilitated diffusion, carrier exs)
- symporters transport two molecules in the same direction
- antiporters move two molecules are transported in opposite directions
coenzymes
organic molecules that bind to the active sites of certain enzymes (ex: NAD, FAD)
kinase
enzyme that phosphorylates
Dehydrogenases
enzymes that remove a pair of hydrogen atoms from a substrate (oxidizing it)
cataplerotic pathways vs anaplerotic pathways (in TCA cycle)
cataplerotic pathways
- precursors for biosynthesis
anaplerotic pathways
- regenerate the TCA intermediates
coenzyme Q (in ETC)
lipid-like carrier that helps in ETC complex I carrying 2 e- from NADH..also helps in complex III carrying 2 e- before passing to cytochrome C
Caspase 9 vs caspase 3 in apoptosis proteolytic cascade
Caspase-9: initiator caspase
- begin the apoptotic program by activating the executioner caspases, which mediate the apoptosis program
- inactive monomers that activate when they dimerize and self cleave
caspase 3: effector caspase
- cleaved and activated by initiator caspases
- executioner caspases have shorter prodomains
Ferroptosis
- intracellular iron-dependent form of cell death that is distinct from apoptosis, necrosis
- characterized by accumulation of oxidatively damaged phospholipids (lipid peroxidation)
