Bio1101 Lab Quiz 1 Study Guide

1.Eyepiece (Ocular lens)

— What you look through to see the specimen.

2.Objective lenses

— These lenses are close to the specimen and
magnify the image.
— Usually, there are 3 or 4 with different powers
(e.g., 4x, 10x, 40x, 100x)

3.Stage

— The flat platform where you place the slide with
the specimen

4.Stage clips

— Hold the slide in place on the stage.

Focus knobs

1. Coarse focus: Moves the stage up and down
quickly to bring the specimen roughly into
focus.
2. Fine focus: Moves the stage slowly for precise
focusing

Light source (or mirror)

— Provides light to shine through the specimen
so you can see it clearly

Condenser-

— Focuses light into a cone shape onto the
specimen

Hypothesis

a specific, testable and falsifiable explanation.

Scientific theory:

a broad explanatory framework supported by repeated evidence
from many tested hypotheses

Binomial Nomenclature

• Every species receives a two-part scientific name.
• Font: both words are italicized.
• Genus comes first and is capitalized.
• Species name follows and is lowercase.
• Example: Homo sapiens.
• Scientific names help biologists communicate unambiguously.

Principle of Chromatography

1. Stationary phase: 2. Mobile phase: 3. Separation happens because

1. Stationary phase:

The medium that doesn’t move (e.g., chromatography paper).

2. Mobile phase:

The solvent that moves through the stationary phase (e.g., water,
alcohol).

3. Separation happens because

○ Some molecules dissolve easily in the solvent → move faster and farther.
○ Some molecules stick strongly to the stationary phase → move slower and
shorter distance.

How Conversions Work

● To convert larger → smaller,
multiply

Examples:

1. Length
● 1 meter = 100 centimeters
● 5 meters = 5 × 100 = 500 cm
2. Mass
● 1 gram = 1,000 milligrams
● 2.5 grams = 2.5 × 1,000 = 2,500 mg
3. Volume
● 1 liter = 1,000 milliliters
● 3 liters = 3 × 1,000 = 3,000 mL

How Conversions Work: ● To convert smaller → larger, divide

Examples:
Length
● Convert 500 centimeters (cm) to meters (m).
● We know: 1 m = 100 cm
● Divide: 500÷100=5 meters
2. Mass Example
● Convert 2,500 milligrams (mg) to grams (g).
● We know: 1 g = 1,000 mg
● Divide: 2500÷1000=2.5 grams
3. Volume Example
● Convert 3,000 milliliters (mL) to liters (L).
● We know: 1 L = 1,000 mL
● Divide: 3000÷1000=3 liters

Why Water is Polar

○ Water has polar covalent bonds
between oxygen and hydrogen.
○ Oxygen is more electronegative
→ pulls electrons closer.
○ Creates partial negative charge
(δ⁻) on O and partial positive
charge (δ⁺) on H.
○ Result: water is a polar
molecule

3. Hydrogen Bonds & Unique Properties

○ Hydrogen bond = weak attraction
between δ⁺ H of one water molecule
and δ⁻ O of another.
○ These H-bonds give water:
■ Cohesion: water molecules stick to
each other → forms droplets.
■ Surface tension: “skin” on water
surface (insects can walk on it).
■ High boiling point: needs lots of
energy to break H-bonds

What is pH?

● pH tells us how acidic or basic (alkaline) a solution is.
● It depends on the concentration of hydrogen ions [H⁺] in the solution.
● The pH scale goes from 0 to 14:
○ Acidic (0–6.9): More hydrogen ions (H⁺).
■ Example: lemon juice, vinegar.
○ Neutral (7): Equal H⁺ and OH⁻.
■ Example: pure water.
○ Basic (7.1–14): More hydroxide ions (OH⁻).
■ Example: soap, baking soda.

What is a Buffer?

A buffer is a solution that resists changes in pH when small amounts of acid or
base are added.
● Why important in biology:
○ Maintains stable pH for enzymes and biochemical reactions.
○ Examples:
■ Blood → pH ~7.4 (too acidic/basic → harmful)
■ Stomach → regulates pH for digestion