Molecular Biology Flashcards
What are the four basic molecules cells use to interact with each other?
Methyl
Hydroxyl
Carboxyl
Amino
What are the four families of small organic molecules?
Sugars
Fatty acids
Amino acids
Nucleotides
Nucleic acids are made from what?
Nucleotides
Proteins are made from what?
Amino acids
Polysaccharides are made from what?
Sugars
What is the main function of nucleic acids?
Code genetic information (DNA)
What type of bond joins polymers of nucleotides?
Phosphodiester bond
What are the five main functions of proteins (also known as the “work horses of the cell”)?
Structure Movement Catalysis Transport Signaling
Polymerization to form peptide bonds between amino acids is a result of what?
Dehydration
Polysaccharides are polymers of _____________ joined by ____________ bonds
Pentose/hexose
Glycosidic bonds
What does amphipathic mean?
Both hydrophilic (head) and hydrophobic (tail) groups
How are lipids formed?
Esterification of acids
What are the four aspects of the “lock and key” model of complementarity?
Shape
Charge
Polarity
Hydrophobicity
Non-covalent interactions between macromolecules allows what to happen?
Tight, highly specific macromolecular bonding
What are the four main types of weak, non-covalent bonding interactions?
Ionic bonds
van der Waals interactions
Hydrogen bonds
Hydrophobic effect
Describe ionic bonds
The absence of what molecule increases the strength of ionic bonds?
Interactions between fully or partially charged groups (current between the two groups)
Absence of water increases the strength of ionic bonds
Describe hydrogen bonds
Hold molecules together Polarized molecules (such as water) can link via hydrogen bonds
Describe van der Waals attractions
At what physical conditions are van der Waals interactions more effective?
Electrons are shared between adjacent nuclei
Adjacent, oppositely charged molecules come close enough to attract, with each molecule having a radius at which van der Waals forces are strongest
More effective in lower temperatures
What is the clathrate cage seen with the hydrophobic effect?
A clathrate cage occurs when one molecule traps another Aggregated states (where water population is less ordered, more entropy) are more energetically favourable
What are the main features seen in prokaryotes that are not seen in eukaryotes?
Inner and outer membranes with cell wall and periplasmic space
Nucleoid instead of nucleus
Plasmid (extra chromosomal, can carry antibiotic resistance)
What are micelles and liposomes?
Artificial membranes made by mixing phospholipids and water
Liposomes have a hydrophilic core and can hide hydrophilic compounds within this core
What does self-assembly mean?
Can change the diameter of liposomes or plasma membranes by adding more phospholipids
How was the plasma membrane involved in defining the first cells?
Phospholipid molecules in prebiotic soup assembled spontaneously
Enclosed self-replicating mixture of RNA and protein molecules
