Comprehensive BioLab Review for Students

biol 1408

Meniscus

The curve at the surface of a liquid in a container, msrmt. read at the bottom of curve

Meter (m)

The metric base unit for length.

Gram (g)

The metric base unit for mass

Liter (L)

The metric base unit for volume

Graduated cylinders

Glassware used for precise volume measurements

Beakers

Glassware used for approximate volume measurements.

Erlenmeyer flasks

Glassware used for mixing and heating liquids.

Digital scales

Must be tared to zero before measuring to ensure accurate mass readings

Metric system prefixes

Used to denote powers of ten: Kilo- (10^3), Hecto- (10^2), Deka- (10^1), Base Unit (10^0), Deci- (10^-1), Centi- (10^-2), Milli- (10^-3), Micro- (10^-6), Nano- (10^-9).

• King Henry Dies By Unaliving Decimals Centimeters Milligrams Microbes and Nanograms.

Volume measurement accuracy

Graduated cylinders accurate for volumes above 10 ml; beakers and Erlenmeyer flasks = approximate volumes; pipettes = less than 10 ml

1 ml of water

Equals 1 g, which can be converted to mg (1000 mg).

Spectrophotometry

measures the absorbancy of light by a solution, using a spectrophotometer

Wavelengths of visible light

Range from ~750 nm (red) to ~350 nm (violet), with the acronym ROYGBIV representing the color order.

Spectrophotometer

Consists of

1. light source

2. sample holder

3. detector

• calibration is essential for accurate readings.

Blank solution

Used to calibrate spectrophotometer, ensures only the sample's absorbance is measured

Absorbance and concentration relationship

absorbancy of a solution increases with protein concentration, measurable at 540 nm using Biuret reagent

Standard curve

Plots absorbance (y-axis) against concentration (x-axis), absorbance = dependent variable

Unknown concentrations

To find unknown protein concentrations, locate the absorbance on the standard curve and determine the corresponding concentration in mg/ml.

Acids

Substances that donate protons (H+)

Bases

Substances that accept protons.

pH

A measure of hydrogen ion concentration.

Anthocyanins

plant pigments, red/pink at low pH, purple at pH 7, blue at high pH

pH measurement techniques

Three methods to measure pH include pH paper, pH meter, and indicator solutions (like anthocyanins).

Buffering capacity

Buffers resist changes in pH when acids or bases are added, and their capacity can be assessed through graphical analysis.

pH scale

Ranges from 0 (acidic) to 14 (basic), with 7 being neutral; each unit change represents a tenfold change in H+ ion concentration.

H+ ion concentration formula

[H+] = 10^(-pH).

Emulsifiers

mixes hydrophobic and hydrophilic components, crucial in biological systems

Hydrophobic molecules

Molecules that repel water

HydroPHILIC molecules

Molecules that attract water, influencing macromolecule structure and function

Carbohydrates

1/4 main classes of macromolecules, with monosaccharides as their monomer.

Proteins

¼ of the macromolecules, amino acids = monomer

Lipids

¼ main classes of macromolecules, fatty acids as their monomer

Nucleic acids

One of the four main classes of macromolecules, with nucleotides as their monomer.

Benedict's solution

A reagent used to detect reducing sugars, with a positive result indicated by a brick red color.

Iodine

A reagent used to detect starch, with a positive result indicated by a blue-black color.

Biuret reagent

detects proteins, positive result = violet color

Sudan III

detects lipids, positive result indicated by red layer.

Nutrition facts labels

info on macromolecule content, allows for identification of starch, protein, lipids, and reducing sugars in food

Total magnification

ToMa. = Ocular lens (10x) X Objective lens (10x) power

Nucleus

An organelle that contains genetic material.

Chloroplast

site of photosynthesis in plant cells

Plasma membrane

Regulates entry and exit of substances in a cell

Plant leaf cells

Cells that contain chloroplasts, cell wall, and cytoplasm.

Onion cells

Cells that contain nucleus, cell wall, and cytoplasm.

Human cheek cells

Cells that contain nucleus, plasma membrane, and cytoplasm.

Eyepiece

The part of the microscope where you look through.

Objective lenses

Parts of the microscope that magnify the specimen.

Stage

The part of the microscope that holds the slide.

Prokaryotes

Unicellular, no nucleus, characterized by simpler structures than eukaryotes

Coccus

A common shape of prokaryotes that is spherical.

Bacillus

A common shape of prokaryotes that is rod-shaped.

Spirillum

common shape of prokaryotes that is spiral

Gram-positive bacteria

Bacteria appearing purple bc of thick peptidoglycan layer

Gram-negative bacteria

Bacteria appears red due to thinner peptidoglycan layer and outer membrane