Chemistry for Biology

Question 1

What is electronegativity?

Answer 1

measure of an atom’s tendency to attract electrons to itself in a covalent bond

stronger tendency = larger electronegativity

Question 2

What is a polar covalent bond?

Answer 2

electrons are shared unequally between two atoms

Question 3

What is a nonpolar covalent bond?

Answer 3

atoms have nearly the same electronegativity (ie. H2, O2, C-C, C-H bonds)

Question 4

What are the key characteristics of living organisms?

Answer 4

1. complexity, with precise spatial organization on several scales
2. ability to change in response to the environment
3. abilities to metabolize and to reproduce
4. capacity to evolve

Question 5

Describe the first law of thermodynamics?

Answer 5

energy can neither be created nor destroyed, it can only be transformed from one form to another

• total energy in universe is constant, but the form it takes changes

Question 6

Why are living organisms energy transformers?

Answer 6

acquire energy from the environment and transform it into a chemical form cells can use

Question 7

Where do all organisms obtain energy from and what is ti used for?

Answer 7

from sun or chemical compounds

used for work (moving, reproducing, building cellular components) and rest is dissipated as heat

Question 8

What is the second law of thermodynamics?

Answer 8

the degree of disorder (number of possible positions and motions of molecules) in the universe tends to increase

• addition of energy increases the order of the system
• living organisms are highly organized, energy is needed to maintain it
• cell is not an isolated system, therefore take into account the cell and its environment
• release of heat as organisms harness energy means total combination of cell and environment’s entropy increases