Building a cell Flashcards
1
Q
Atom
A
The smallest part of an element
2
Q
The Hydrogen atom
A
- simplest element
- no neutron
- 1 electron = unstable
- 1 proton
3
Q
Protons
A
- In nucleus
- has mass
- positive charge
4
Q
Neutrons
A
- has mass
- no charge
- what defines isotopes
5
Q
Electrons
A
- has mass
- negative charge
- in orbital/energy shell/volume
6
Q
What do energy shells do
A
overcome electrons’ attractions to protons in the nucleus
7
Q
how to electrons move to higher shells
A
absorb energy
8
Q
how do electrons move to lower shells
A
emit energy
9
Q
how do electrons leave atoms
A
collisions
10
Q
Molecules
A
- Form when at least 2 atoms are chemically bonded (by valence electrons)
11
Q
Covalent bond
A
- Shared valence electrons
-> Ex. Hydrocarbons - Strong
- Only break in water at boiling point (100)
12
Q
Ionic bond
A
- More electronegative (receiving) atom steals an electron
- Easily broken in water
- Easily formed in water
13
Q
Polar Covalent Bonds
A
- Unequal sharing of electrons between H and O atoms
- O atoms are more electronegative/negative pole (electrons are repulsed by O and attracted to H)
14
Q
H-bonds
A
- Sharing of an H atoms between polar molecules
- Forms btw a Hydrogen and a more electronegative atom (O)
15
Q
Properties of H-bonds
A
- Weak individually
-> Gives big molecules the ability to break apart (Ex. rungs of DNA) can break and replicate
-> Allow things like enzymes to change shape - Collectively strong
- Require less energy transfer than COVALENT bonds
- H-bonds form hexagonal lattice (ice) that is less dense than water (although it is strong)
16
Q
Hydrophillic
A
Polar likes polar
- helps water-soluble molecules and ions dissolve and interact with watery environment (ex. inside and outside cells)
17
Q
Hydrophobic
A
Non-polar likes non-polar
- Drives organization of cell membranes (phase separation)
-> Phase separation forms liquid bilayers
-> If phases mix, big oil droplet
18
Q
Bond Energy
A
- Amount of energy needed to separate 2 bonded atoms
19
Q
What determines the state of water?
A
H-bonds
- Why water is not a gas all the time: cold slows down atoms and forms ice (solid)
- Add heat = atoms move faster = turns into liquid or gas
- As a liquid, H-bonds break continuously but randomly
20
Q
Properties of water
A
- Water is a solvent
-> Ionic bonds break easily in water bc of the charges surrounding it (water is a polar molecule that has + and - ends) - The attraction of water molecules to ions helps facilitate the movement of ions in and out of neurons
-> Contributing to electrical signaling - Liquid water is cohesive (things float on it)
-> Hydrophobic - Liquid water is adhesive (straw sucks up water)
-> Hydrophilic - Water has a high heat of vaporization
- Water has high heat capacity
