Topic 2: Origins and Biomolecules Flashcards
Describe Stanely Millers experiment. Why is it important?
Biomolecules reacted together; it was the right conditions, so things just appeared.
What is the “RNA World Hypothesis?”
The first cell was an enclosed bit of self-replicating RNA in the phospholipid bilayer. Supporting observations: forms spontaneously, RNA can self-replicate, and RNA can form enzymes
Describe the evolution of metabolism
When cells became more complicated needed new energy sources. Cells became ATP dependent, later on, take energy from the sun and make its own glucose, later some cells took oxygen to break down glucose more efficiently.
What process is believed to have brought about the existence of mitochondria and chloroplasts in eukaryotic cells?
Originate from endosymbiosis, one cell living inside the other. Evidence, Mitochondria and chloroplasts having own DNA replicated each time cell divides.
Compare and contrast prokaryotes and eukaryotes
Prokaryotes don’t have a nucleus, and Eukaryotes do. Prokaryotes are small eukaryotes big. Prokaryotes do not have membrane-bound organelles eukaryotes do. Prokaryotes have circular DNA and eukaryotes have linear DNA.
Covalent bonds
The strongest interaction between atoms. Forms when two atoms come together and share electrons.
Ionic bonds
Bonds with strong differences in electronegativity. Electrons completely transferred one nucleus instead of being shared.
Hydrogen bonds
noncovalent bonds formed between oxygen with a partial negative charge. Weaker than ionic bonds.
Hydrophilic molecules
water-soluble molecules ex. ions and polar molecules
Hydrophobic molecules
water in soluble molecules ex. nonpolar molecules
amphipathic molecules
some parts are hydrophilic and other parts are hydrophobic in the molecules
What are carbohydrates?
Complex sugars, functions;
Energy storage: Starch and Glycogen are readily hydro soluble by enzymes,
cell wall & structure: cellulose not hydro soluble, bacteria can break it down, chitin animal equivalent signaling: can be attached to proteins inside cell and on all cell surfaces.
What are lipids?
Fatty acids, hydrophobic, has long hydrocarbon chains and carboxyl polar group and nonpolar carbon/hydrogen bonds. Used for energy storage and signaling
what are nucleic acids
DNA or RNA, stores genetic information. Used for information storage, energy and signaling.
What are proteins?
used for movement, hormones, enzymes, transport, immune system, structural components.
Dehydration reaction
two monomers form together through loss of water
Hydrolysis
Polymers are broken down into monomers by adding water
General structure of Carbohydrates
Simple sugar, monosaccharides joined together through glycosidic bond between carbons to make polysaccharide.
Complex sugar
Polysaccharide: a large number of sugars involved, like glycogen and starch, the storage form of carbohydrates for animals and plants. Cellulose principle structure component. Chitin forms the exoskeleton of crabs and insects.
Common features of phospholipids
2 fatty acids and phosphate groups. Principle component of cell membrane. 2 acetyl chains can either be held together by glycerol. Used for energy storage. Amphipatic molecule
What is the weird phospholipid?
Sphinglolipids: amino acid bound to serine instead of glycerol
What is structure of triglyceride?
3 fatty acids are linked together by glycerol. insoluble in water. clump together as fat droplets. Efficient from of energy storage.
DNA vs RNA
DNA: long term
RNA: short term
What are the bonds that hold nucleotides together?
phosphodiester bond: polymerization of nucleotides to from nucleic acids. Happen between 5’ phosphate of one nucleotide and 3’ hydroxyl of another.
