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 are accurate for volumes above 10 ml; beakers and Erlenmeyer flasks provide approximate volumes; pipettes are accurate for volumes less than 10 ml.

1 ml of water

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

Spectrophotometry

The measurement of light absorption 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 the spectrophotometer, ensuring that only the sample's absorbance is measured.

Absorbance and concentration relationship

The absorbance 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

Pigments found in plants that change color based on pH: red/pink at low pH, purple at neutral, and 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

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

Proteins

¼ of the macromolecules, amino acids = monomer

Lipids

One of the four main classes of macromolecules, with 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

A reagent used to detect proteins, with a positive result indicated by a violet color.

Sudan III

detects lipids, positive result indicated by red layer.

Nutrition facts labels

Provide information on macromolecule content, allowing for the identification of starch, protein, lipids, and reducing sugars in food products.

Total magnification

Calculated by multiplying the ocular lens (10X) by the objective lens power.

Nucleus

An organelle that contains genetic material.

Chloroplast

The 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 organisms without a 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

A common shape of prokaryotes that is spiral.

Gram-positive bacteria

Bacteria that appear purple due to a thick peptidoglycan layer.

Gram-negative bacteria

Bacteria appears red due to thinner peptidoglycan layer and outer membrane