bio lab

Microscope

An instrument used to see objects that are too small to be seen by the naked eye.

Ocular lens

Eyepiece of the microscope, usually 10x magnification.

Objective lens

Primary magnification lens of the microscope.

Coarse adjustment knob

Large adjustments made to bring the specimen into general focus.

Fine adjustment knob

Used for precise focusing of the specimen.

Stage

Platform where the slide is placed for observation.

Diaphragm

Regulates the amount of light that reaches the specimen.

Interphase

Stage of the cell cycle where the nucleus appears normal.

Prophase

First stage of mitosis where chromosomes become visible.

Metaphase

Stage of mitosis where chromosomes line up at the cell's equator.

Anaphase

Stage of mitosis where chromosomes are pulled apart to opposite poles.

Telophase

Final stage of mitosis where new nuclei form around separated chromosomes.

Molarity (M)

Concentration measure defined as moles of solute per liter of solution.

Percent Solutions (%)

Calculated as (grams of solute / mL of solvent) × 100.

Dilution equation

C₁V₁ = C₂V₂ used to solve dilution problems.

Micropipette

Tool used to measure volumes less than 1 mL, usually in microliters.

Serological pipette

Measures and transfers volumes between 1 and 10 mL.

Graduated cylinder

Instrument for accurately measuring liquid volumes between 10 and 1000 mL.

Beaker

Container for holding and mixing liquids, not highly accurate.

Vortex mixer

Device that mixes solutions thoroughly.

Calibration

Process of adjusting the spectrophotometer to accurately measure absorbance.

Wavelength (λ)

The distance between successive peaks of a wave, important for spectrophotometry.

Absorbance

The measure of the amount of light absorbed by a solution.

Cuvette

A small tube that holds samples for measurement in a spectrophotometer.

Centrifuge

Device that separates contents of a solution by density.

Gel electrophoresis

Technique used to separate DNA fragments based on size.

TAE buffer

Buffer solution that conducts electricity during electrophoresis.

DNA ladder

Size standard used in gel electrophoresis to compare DNA fragment sizes.

ONPG

Substrate for lactase enzyme that is broken down to produce a measurable yellow product.

ONP

Yellow product formed from the breakdown of ONPG by the enzyme lactase.

Control variables

Conditions that are kept constant throughout an experiment.

Independent variable

The factor that is changed or manipulated in an experiment.

Dependent variable

The outcome measured in an experiment.

Sample size

The number of subjects or samples included in a group study.

Replicates

Repeated trials of a measurement to ensure reliability of results.

Raw data

The raw, unprocessed experimental results.

Summary data

Processed data presenting means and standard deviations.

Scatter plot

Graph used to display the relationship between two continuous variables.

Column graph

Graph used to represent categorical data in columns.

Error bars

Graphical representation of the variability of data.

Hypothesis

A proposed explanation for a phenomenon or an educated guess.

Prediction

A statement forecasting the outcome based on the hypothesis.

Meristem

Growth area in plants where cell division occurs.

Microcentrifuge tube

Small tube used to hold samples during centrifugation.

Gel comb/mold

Tool used to make wells in gel for electrophoresis.

Vortex mixer

Instrument used to mix samples with a vortex action.

Electrophoresis chamber

Equipment that runs an electric current through gel for sample separation.

Tris-HCl

Buffer solution used to maintain stable pH during experiments.

Chloroform

Chemical used to separate organic layers during DNA extraction.

Isopropanol/Ethanol

Alcohols used to precipitate DNA from aqueous solution.

Microbeads

Small beads used to aid in breaking cell walls during lysis.

Agarose

Gel material used in electrophoresis to separate DNA fragments.

Gel Red

DNA stain that allows visualization of DNA under UV light.

PBS

Phosphate-buffered saline, used as a buffer for enzymatic reactions.

Na₂CO₃

Chemical used to stop the enzyme reaction in assays.

Standard deviation (SD)

Measure of the amount of variation or dispersion in a set of values.

Light absorbance

Amount of light absorbed by a solution measured in spectrophotometry.

Aim of the enzyme reaction

To measure the concentration of ONP produced from ONPG by lactase.

Movement in gel electrophoresis

DNA fragments move towards the positive electrode due to their negative charge.

Frontal surface view

Visual orientation when using a microscope to observe tissues.

Higher magnification effect

Increases detail but decreases the field of view and depth of focus.

Band interpretation

Analysis of band patterns on gel electrophoresis to determine fragment sizes.

Size standard

Reference used in gel electrophoresis to ascertain sizes of other DNA fragments.

DNA extraction process

Involves breaking cell membranes, separating layers, precipitating DNA, and washing.

Results summary analysis

Method of extracting mean and standard deviation from raw data for interpretation.

Spectrophotometer purpose

To measure the absorbance of light by solutions to determine concentration.

Centrifugation

Process of spinning samples at high speed to separate components by density.

Onion root tip observation

A method to study different stages of mitosis by examining root tip cells.

Chemical function in DNA extraction

Use of CTAB for cell lysis and chloroform for phase separation.

Absorbance-concentration relationship

Higher absorbance readings correspond to higher concentrations in spectrophotometric analysis.

Electrophoresis principle

Separates DNA fragments based on size using an electric field.