Unit 1

Question 1

What properties define a living organism? (The five fundamental characteristics)

Answer 1

They…

• obtain and use energy (energy)
• are made up of cells (cells)
• process information (information)
• replicate (replication)
• evolve as populations (evolution)

Question 2

The Cell Theory

Answer 2

1. All organisms are made of cells.

2. All cells come from preexisting cells.

Question 3

The Theory of Evolution by Natural Selection

Answer 3

Species change through time because individuals with certain heritable traits produce more offspring than other individuals do.

Question 4

A Phylogenetic Tree

Answer 4

• A graphical representation of the evolutionary relationships between species.
• Estimated by analyzing similarities and differences in traits
• Species that share distinctive traits are closely related and are placed close to each other on the tree of life

Question 5

Two Conditions of Natural Selection

Answer 5

1. Individuals within a population vary in characteristics that are heritable.
2. In a particular environment, certain versions of these heritable traits help individuals survive better or reproduce more than other versions do.

Question 6

Spontaneous Generation

Answer 6

The hypothesis that cells spring to life spontaneously

Question 7

All-cells-from-cells

Answer 7

The hypothesis that cells are produced only when preexisting cells grow and divide.

Question 8

Pasteur’s experiment

Answer 8

Purpose: To test whether the spontaneous generation or all-cells-from-cells hypothesis was correct.
Set up: Two glass flasks filled with sterilized broth. One flask is straight-necked (for all-cells-from-cells hypothesis). The other is swan-necked (for spontaneous generation hypothesis).
Result: The straight-necked flask grew bacteria and fungi. The swan-necked flask did not grow anything. Therefore, the all-cells-from-cells hypothesis was correct.

Question 9

What did researchers look at in organisms to help them develop the phylogenetic tree?

Answer 9

• A molecule found in all organisms

- This molecule is called small subunit ribosomal RNA (rRNA).

Question 10

rRNA

Answer 10

• large and complex
• made up of sequences of four smaller chemical components called ribonucleotides (A, U, C, G)
• an essential part of the machinery that all cells use to grow and reproduce

Question 11

Case Study of TB

Answer 11

Patient admitted and treated with rifampin. “Cured”. 10 months later back with same symptoms. Treated with rifampin again. Died 10 days later.
Hypothesis: A “new” strain of TB evolved inside patient.
Test: Determine DNA sequence of TB genome inside patient’s lung: before and after treatment of patient with rifampin
Experiment: Rifampin kills most of the bugs, patient is “cured”. Mutant cells proliferate, new major infection established in lungs…patient sick again. Second round of drug therapy ineffective because bacteria carry mutation that prevents rifampin from binding to the target.
Mutation was present in population, at low frequency prior to antibiotic treatment.

Question 12

Evolution by Natural Selection has both random and nonrandom components. What are they?

Answer 12

Generation of the raw material (genetic variation) is random, while the selection is nonrandom.

Question 13

Basic Properties of Cells

Answer 13

Cells…

• are complex/organized
• have a genetic blueprint and ability to translate
• can reproduce themselves from preexisting cells
• can acquire, transform, and utilize energy
• can carry out chemical reactions
• can engage in mechanical activities
• can respond to stimuli
• can self-regulate