Biology 118 Exam 1

What makes viruses unique among other living organisms when it comes to reproduction?

viruses reproduce only inside other cells (how viruses spread from places to places)

A biologist wants to test the effectiveness of a new food additive on causing growth on mice. An effective *control group* would be one that:

was fed the same ration *without the food additive*

All of the following are properties of water EXCEPT:

water speeds up metabolism

To distinguish between prokaryotes and eukaryotes, we need to consider:

whether the genetic information is enclosed in a protective layer of phospholipid membrane bilayer

Which source of carbohydrates will be digested the slowest?

whole wheat bread

Which of the following is a scientific *hypothesis*?

People catch colds because of exposure to cold temperature

Whether something is alive is best determined by:

Presence of *multiple* characteristic of life

The formulation of hypotheses represents a critical step in the scientific process. In the simplest terms, what is a hypothesis?

an explanation

The scientific method is used to:

answer specific questions about the natural world

What is the characteristic of life that allows living organisms to maintain a relatively constant environment/*internal equilibrium* despite inevitable external changes

homeostasis (the ability to maintain a constant internal environment in response to environmental changes. )

The variables that in an experiment is *under the control* of the researcher is called:

independent variable

Atoms that bears a positive or negative charge are known as

ions

The most common atom in the atmosphere is:

nitrogen

*Enzymes* (also known as catalysts) are macromolecule that belong to the _______ category:

proteins

The cell theory proposes that all living organisms are made of cells

true

the substance that dissolves almost anything in it is called the solvent

true

If you were going to build a large macromolecule or polymer it needs to *be strong*. What type of chemical *bond* do you think would work best for building macromolecules?

*co*valent

Which of the following is NOT an essential atom to support life among living cell?

- *aluminum* (carbon, hydrogen, oxygen, nitrogen, aluminum)

Which of the following is support for the *theory of evolution* which states that all life on Earth arose from *a common ancestor*?

- All life on Earth shares a common organic chemistry - All life on Earth had the same genetic materials - All life on Earth has the same basic cellular structures - All life on Earth performs the same basic metabolic processes

Ideally, an experiment studying the effect of a cold medicine should have

- a control group - a large sample size - subjects randomly assigned to experimental and/or control group - use placebo (think about what you need in an experiment)

Statistical analysis (graphs) of experimental data determines _________ what?

- the amount of bias in the experiment design - the likelihood that the results are due to the experimental treatment - whether the experiment proves that the hypothesis being tested is correct - whether the proper controls were used in the experiment

Scientists are often *hesitant to believe the results of a single experiment testing* particular treatment, even when the result are peer-reviewed and statistically significant. This is because

- the experiment and control groups may not have been as alike as possible - if the experiment used a model organism, the results may not be true for humans a single experiment may not have eliminated many alternate hypotheses - unintentional biases may have affected the results of the experiment (need multiple experiments to confirm results)

Although planet earth is 75% covered by water, only ______% constitutes the usable volume available to fulfill the needs of living beings

0.5%

Which one of the following would most biologists consider to be alive?

DNA - present *Mobility - absent* Uses energy - present Growth - present Reproduces - present

Why does water display the unique properties we have been learning so far?

Because of its ability to *form hydrogen bonds*

Why food production consists ultimately in "farming the sun"?

Because the *sun* triggers *photosynthesis* in plants

Atoms are the smallest units of matter. Who first coined this term?

Democritus

Consider an experiment in which subjects are given a pill to test its effectiveness on reducing the duration of a cold. Which of the following is the best way to treat the control group?

Give the control group a pill that does not affect colds. (placebo)

Which answer below will provide all of the essential amino acids in a meal?

Hamburger and corn and beans

Which statements is true when comparing lemon juice (acidic) to baking coda (basic)?

Lemon juice has more H+ compared to baking soda

For many centuries the theory of spontaneous generation explained how life began however, it was eventually proven *incorrect* in the 19th century by whom?

Louis Pasteur

The beaches at a nearby lake have been closed because of *high E. coli counts*. The lake is surrounded by *agricultural area* and *summer cottages*. We know that different species of *vertebrates* have different E. coli strains in their digestive tracts. Which of the following represents an HYPOTHESIS for the source of the high E. coli counts?

Runoff from dairy farms causes high E. coli counts

Which statement would you agree with?

Science has room for different views among scientists

Which of the following best describes the structure of the cell membrane?

a double layer of *lipids with proteins* embedded in it

The pH of a water solution is 4.77. This solution is:

acidic

The first living organisms to inhabit Earth about *3.5 billion* years ago were:

bacteria

Heart disease results from plaque narrowing or blocking blood vessels in the muscle tissue of the heart. For decades scientists have believed that heart disease is caused by stress, genetics and poor diet. A new hypothesis is that the infectious bacteria C. pneumoniae causes heart disease.

blocked blood vessels have high levels of bacteria and plague - free blood Vessels have no bacteria

All *plant* cells possess a *unique organelle* and this is the _______, which is necessary for them to do *photosynthesis*:

chloroplast

Which of the following statements is a testable, scientific hypothesis?

eating fish reduces the chances of getting a stroke

Darwin's theory of evolution supports the idea that species do not change over time

false

Photosynthesis is the chief metabolic reaction among animal cells

false

Sugars like glucose are the molecules that provide energies needed by cells to do work.

false

The first step of the scientific process consists in making a prediction of a natural phenomenon

false

all eukaryotes possess a cell wall

false

Results from one test of a new drug are found to be statistically significant; thus the hypothesis:

should be tested again

Certain protein molecules act as enzymes and thus, speed up metabolic reactions within cells

true

Glucose is the most common simple sugar in nature

true

Glycogen is complex carbohydrate that is stored in the cells of the liver

true

Phospholipids are the typical fats that line biological membranes

true