Lecture 1

Question 1

Biology matters because…

Answer 1

it is essential to our lives.

Question 2

Biology is the basis of…

Answer 2

medical practice.

• For example, research explains how organisms work and how disease develops.
• Annual vaccinations are administered to prevent diseases caused by evolving microbes (i.e. Ebola in 2014).

Question 3

Biology informs…

Answer 3

public policy.

• For example, study to prevent overfishing bluefin tuna uncovered misunderstood migration of western and eastern breeds of the fish.
• In 2014, there was a potential ban on recreation and commercial fishing.

Question 4

Biology is crucial for…

Answer 4

understanding ecosystems.

• Human activity has significantly increased the rate of change of ecosystems.
• Climate change is now visible. The Muir and Riggs glaciers have significantly melted into oblivion since thirty years ago.

Question 5

To study life, scientists use…

Answer 5

observation, data, experimentation, and logic.

Question 6

Scientific Methodology

Answer 6

• There are 5 steps: Observation, speculation, hypothesis, prediction, and experimentation.
  1) Making observations
  2) Asking questions
  3) Forming hypotheses
  4) Making predictions based on the hypotheses
  5) Testing predictions by making additional observations or conducting experiments.

Question 7

Inductive logic

Answer 7

Tool used in scientific method to develop a hypothesis based on observations and/or facts.

Question 8

Deductive logic

Answer 8

Tool used in scientific method to generate predictions based on the hypothesis. It asks the question, “what else is true if the hypothesis is true?”
It starts with a statement that is believed to be true (hypothesis) and then determines what facts would also have to be true to be compatible with the hypothesis.

Question 9

Experiments test…

Answer 9

predictions.

Question 10

Hypothesis is defined as…

Answer 10

a tentative answer.

Question 11

Controlled experiment…

Answer 11

manipulates one or more factors being tested.

Question 12

Independent variable…

Dependent variable…

Answer 12

is a manipulated factor.

is a measured response.

Question 13

Comparative experiment…

Answer 13

looks for differences between samples,
variables are not controlled,
data are gathered and compared.

Question 14

Statistics determine if…

Answer 14

a difference supports or falsifies a hypothesis.

measure of significance

Question 15

Statistical Tests (3 points)

Answer 15

• Results are probabilities: What is the probability that the differences could be due to random variation?
• Null hypothesis states that no difference exists.
• Differences measured are significant if probability of error is </=5%.

Question 16

Life is defined according to…

Answer 16

several characteristics.

Question 17

8 Characteristics of living organisms:

Answer 17

1. made of a common set of chemicals.
2. building blocks are cells.
3. convert molecules into new forms.
4. extract energy to do work.
5. universal genetic doe to produce proteins.
6. share fundamental genetic similarities.
7. populations evolve.
8. self-regulate for survival (ex. homeostasis in humans).

Question 18

What are essential to life?

What is a major requirement and component of a ___?

Answer 18

Cells.

Water.

Question 19

Chemical features of water (3)

Answer 19

• It is a polar molecule (the negative charge of one water molecule is attracted to the positive charge of another)
• Hydrogen bond binds two water molecules.
• It is a tetrahedral shape with four pairs of electrons in the outer shell repelling each other.

Question 20

Properties of water (7)

Answer 20

1. ice floats (it is a crystalline structure; solid water is less dense than liquid water).
2. water forms gas when hydrogen bonds break.
3. ice requires a lot of energy to melt; freezing releases a lot of energy.
4. high heat capacity (specific heat; amount of heat energy to raise temperature of 1 gram water 1oC)
   
   • ponds freeze top to bottom.
   • water is an insulator because of the barrier formed on the top when it freezes.
5. high heat of vaporization
   
   • energy required to change water from liquid to gas.
6. cohesion
   
   • capacity of water molecules to resist separation (ex. sequoia trees get plenty of water supply due to water molecules sticking together vertically, which is why they are able to grow so tall)
7. surface tension
   
   • water molecules at surface are hydrogen bonded to water below.

Question 21

Aqueous solution (3 points)

Answer 21

• solution is a substance (solute) dissolved in liquid (solvent)
• concentration or amount is measured in moles
  
  • mole: the amount of substance (grams) that is numerically equal to its molecular weight
  • one mole = 6.02 x 10^23 molecules = Avogadro’s number.
• A 1 molar solution (1M) is 1 mole of a substance dissolved in 1 liter of water

Question 22

If added to water, acids ____ hydrogen ions and bases ___hydrogen ions.

Answer 22

release

accept

Question 23

Is water acid or base?

Answer 23

It is both weak acid and weak base.

Two water molecules can protonate and deprotonate to form a hydroxide and a hydronium.

Question 24

pH

Answer 24

• [H+] is measured in moles per liter (molarity)
• pure water, [H+] = 10^-7 M, pH = 7
• 1M HCl, [H+] = 1M, pH = 0
• 1M NaOH, [H+] = 10^-14 M, pH = 14
• Easier to work with logarithm of [H+]
  
  • pH is negative log of molar concentration of H+
  • pH = -log [H+]

Question 25

Why does pH matter? (2)

Answer 25

• Reactions transfer ions between molecules, which in turn influence pH of solution.
  
  • Ion transfer influences reaction rate.
• 3D structure (and function) of biological molecules is influenced by pH.
  
  • Eg. COO- reacts with polar region of water
  • Eg. COOH may fold differently due to reduced tendency (hydrophobic) to react with water

Question 26

Acid rain

Answer 26

• “Liming” is used in Norway and Sweden, but not in the U.S.
• Calcium carbonate is fish-friendly :)
• CaCO3 Ca^2+ + CO3^2-
• CO3^3- + H+ HCO3-

Question 27

Buffers (2)

Answer 27

• Maintain pH
• A buffer is a mixture of weak acid and weak base
  
  • Eg. Carbonic acid (H2CO3) and bicarbonate ion (HCO3-)
  • Eg. of human buffer is calcium carbonate supplement.

Question 28

Properties of water are explained by…

Answer 28

its atomic and molecular structure.

read paper on silver