Biology matters because…
it is essential to our lives.
Biology is the basis of…
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).
Biology informs…
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.
Biology is crucial for…
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.
To study life, scientists use…
observation, data, experimentation, and logic.
Scientific Methodology
- 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.
Inductive logic
Tool used in scientific method to develop a hypothesis based on observations and/or facts.
Deductive logic
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.
Experiments test…
predictions.
Hypothesis is defined as…
a tentative answer.
Controlled experiment…
manipulates one or more factors being tested.
Independent variable…
Dependent variable…
is a manipulated factor.
is a measured response.
Comparative experiment…
looks for differences between samples,
variables are not controlled,
data are gathered and compared.
Statistics determine if…
a difference supports or falsifies a hypothesis.
measure of significance
Statistical Tests (3 points)
- 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%.
Life is defined according to…
several characteristics.
8 Characteristics of living organisms:
- made of a common set of chemicals.
- building blocks are cells.
- convert molecules into new forms.
- extract energy to do work.
- universal genetic doe to produce proteins.
- share fundamental genetic similarities.
- populations evolve.
- self-regulate for survival (ex. homeostasis in humans).
What are essential to life?
What is a major requirement and component of a ___?
Cells.
Water.
Chemical features of water (3)
- 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.
Properties of water (7)
- ice floats (it is a crystalline structure; solid water is less dense than liquid water).
- water forms gas when hydrogen bonds break.
- ice requires a lot of energy to melt; freezing releases a lot of energy.
- 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.
- high heat of vaporization
- energy required to change water from liquid to gas.
- 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)
- surface tension
- water molecules at surface are hydrogen bonded to water below.
Aqueous solution (3 points)
- 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
If added to water, acids ____ hydrogen ions and bases ___hydrogen ions.
release
accept
Is water acid or base?
It is both weak acid and weak base.
Two water molecules can protonate and deprotonate to form a hydroxide and a hydronium.
pH
- [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+]
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Lecture 128
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Lecture 4 - Cell basics, Microscopes, Prokaryotes, and Eukaryotes50
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Lecture 6 - Mitosis and Meiosis43
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Lecture 2 - Proteins and Enzymes55
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Lecture 5 - Nucleic Acids, DNA Replication36
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Lecture 3 - Molecules of Life: Carbs, Lipids, Membranes38
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Lecture 7 - From DNA to Protein: Gene Expression35
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Lecture 8 - Regulation of Gene Expression32
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Lecture 9 - Mutations and Molecular Medicine, PCR34
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Lecture 10 - Energy, Enzymes, and Metabolism33
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3-5: Biotechnology7
