Week 1 Flashcards
What is the first law of thermodynamics?
Energy cannot be created or destroyed, only transformed
What is the second law of thermodynamics?
The degree of disorder (entropy) in the universe tends to increase
Define a ‘cell’
The simplest entity that is able to independently sustain life.
What are the three characteristics that define a cell.
There is a cell membrane, the cell is able to metabolize and contains genetic information.
What are viruses
Extremely small infectious agents that generally consist of of a few genes inside a protein capsid. Some viruses also have an outer phospholipid envelope.
What is lysis
The process by which an infected cell explodes to release more virus particles.
What are retroviruses (Group VI-VII in the Baltimore classification system)?
Viruses that use reverse transcriptase to transcribe RNA to DNA. They have the highest mutation rate among viruses.
What are the 4 characteristics of living organisms.
Complexity (precise cellular structure), the ability to respond to stimuli, the ability to reproduce and the capacity to evolve.
What is homeostasis?
The maintenance of a stable internal environment in the face of a changing external environment
What are covalent bonds?
Bonds that form when valence electrons are shared between atoms to create a full outer shell.
What are ionic bonds?
A bond formed between oppositely charged ions
What is hydrogen bonding?
Bonds formed due to the electrostatic attraction between the hydrogen atom and the electronegative atom.
Why is carbon considered to be the backbone of all organic molecules?
Due to the amount of valence electrons in its outer shell, carbon is able to form up to 4 covalent bonds, allowing for the creation of more complex structures.
What are the most abundant elements in cells
Carbon, hydrogen, oxygen, nitrogen and phosphorus.
Define Van der Walls forces
A weak, electrostatic attraction between molecules due to the motion of electrons along long, non-polar structures.
Are polar molecules hydrophobic or hydrophilic?
Hydrophilic
Are non-polar molecules hydrophobic or hydrophilic?
Hydrophobic
What does the term ‘pH’ refer to?
The amount of protons in a solution.
Why is solid water less dense than its liquid form?
When water molecules are frozen, 4 stable hydrogen bonds are able to be created which creates a crystalline lattice structure.
What is the ‘central dogma’ in biology?
a term used to describe the flow of information in a cell, from DNA to RNA to protein.
What is the main difference between a prokaryotic and a eukaryotic cell?
A prokaryotic cell does not contain a nucleus or other membrane-bound organelles, whereas a eukaryotic cell does.
