Lab Safety and Biological Concepts

Flashcards covering laboratory safety, microscopy, cell biology, diffusion, enzymes, the scientific method, spectrophotometry, measurements, and pH.

Provides detailed chemical hazard, storage, and first aid information.

Safety Data Sheet (SDS)

Items such as lab coat, goggles, and gloves that protect the wearer from hazards.

Personal Protective Equipment (PPE)

Remove the glove and wash the area immediately.

What should you do first if you spill a corrosive chemical on your glove?

Danger indicates the severity of the hazard.

Signal Word for Severe Hazard

To ventilate harmful vapors.

Fume Hood Function

False, jewelry and long sleeves should not be worn in the lab.

Is it acceptable to wear jewelry or long sleeves in the lab?

Blue represents health hazards.

NFPA Diamond Health Hazard Color

Indicates special hazards.

What does the white color on the NFPA diamond indicate?

Never!

When can you leave a hotplate alone?

PPE items include?

Gloves, goggles, and lab coats.

To calibrate and establish a baseline.

Importance of Blank Cuvette in Spectrophotometry

No.

Can you recap a chemical container with any lid?

Seek guidance from your instructor.

What should you do before using unfamiliar equipment?

You must always use the 4x objective lens first when focusing a specimen.

Smallest Objective Lens

Coarse Adjustment with 40x Objective

False, do not use the coarse adjustment knob with the 40x objective lens

Multiply the ocular lens magnification by the objective lens magnification.

Total Magnification Formula

Regulates the amount of light passing through the specimen.

Diaphragm Function in Microscope

400x.

Total Magnification of a 10x and 40x Lens

A plasma membrane.

All cells have what feature?

False, it's found in every type of cell.

Plasma Membrane Presence

Nucleus.

Organelle in Both Plant and Animal Cells

Cytoplasm, plasma membrane, ribosomes.

Structures in Prokaryotic and Eukaryotic Cells

Cell wall, central vacuole, chloroplasts.

Components in Elodea Cell Slide

Central vacuole.

Distinctive Feature in Plant Cells

Lack of nucleus.

Difference Between Prokaryotic and Eukaryotic Cells

Chloroplast.

Photosynthesis Organelle

Only plants have a cell wall, chloroplasts, and a large central vacuole.

Key Differences Between Plant and Animal Cells

No.

Does size determine cell type?

Osmosis.

Diffusion of Water Across Membrane

Moves from high to low concentration.

Concentration Reference in Diffusion

It is the diffusion of water across selectively permeable membranes.

Osmosis Statements

True, they move in both directions.

Direction of Water Molecules in Osmosis

No.

Does facilitated diffusion require energy?

Facilitated diffusion.

Type of Diffusion Requiring Membrane Proteins

False, it's not a good model.

Dialysis Tubing as Plasma Membrane Model

Orange-red color after heating with Benedict's reagent.

Evidence of Glucose Diffusing from Dialysis Bag

The shrinkage of cytoplasm and pulling of the membrane from the cell wall.

Plasmolysis Definition

A plant cell in salt water.

Where did we see plasmolysis take place?

Indicates enzyme activity via color change.

Guaiacol Function in Enzyme Activity

False, it does not bind directly to the enzyme's active site.

Guaiacol and Active Site

False, it will not increase activity with more substrate.

Enzyme Saturated with Substrate

Active site.

Area Where Substrate Binds on Enzyme

Keep on ice; add enzyme first; mix enzyme last.

Best Practices for Enzyme Activity Preservation

Enzymes are specific to their substrates.

Enzyme Specificity Explanation

False.

Do enzymes increase activation energy?

Enzyme denatures and loses its three-dimensional structure.

Effect of Boiling Temperatures on Enzyme Activity

It sets a baseline for absorbance.

Why is Tube 1 used as a blank in spectrophotometry?

Starting the timer within 20 seconds.

Critical Spectrophotometer Timing Step

Lipids.

What does Sudan IV test for?

Starch.

Positive Result for Lugol's Iodine is

Turns violet in the presence of proteins.

Biuret Reagent Color Change

Repeating units of glucose.

What is starch made of?

Glucose, fructose, galactose.

Reducing Sugars Examples

Use Biuret reagent.

Testing Proteins

Claims there is no significant difference caused by the experimental treatment.

Null Hypothesis

Conduct an experiment.

Step After Forming a Hypothesis

The variable changed or controlled by the researcher.

Independent Variable Defined

False, it is not manipulated during an experiment.

Dependent Variable Misconception

Hypothesis.

Testable Explanation Based on Observations

The group that receives no treatment.

Control Group Definition

Reproducibility, use of control groups, multiple trials.

Characteristics of a Good Experiment

Ensures that the method is working as intended.

Positive Control Purpose

Observation, Hypothesis, Conduct Experiment, Analyze Data, Draw Conclusion.

Scientific Method Steps

Absorbance is directly proportional to concentration.

Beer's Law

484 nm.

Wavelength for Blue #1 Dye

Useful for estimating unknown concentrations.

Standard Curve Purpose

Cuvette.

Spectrophotometer Component for Liquid Sample

Handle cuvettes carefully; insert blank; zero the machine.

Steps Before Measuring Absorbance

Concentration.

X-axis Variable in Standard Curve

Each Dye in Spectrophotometry

Has a unique peak absorbance for identification.

Calibrates the spectrophotometer to ignore the solvent.

Purpose of Blank Cuvette

To get accurate measurements.

Why is blanking necessary in spectrophotometry?

Negative logarithm of hydrogen ion concentration.

pH Definition

Bromocresol purple.

pH Change Indicator

Resists change in pH when acid or base is added.

Buffer Function

Gram (g).

Base Unit for Mass in Metric System

µL.

Microliter Abbreviation

Kilo.

Prefix for 1,000 Units

Use a 5 mL pipette.

How to Measure 5 mL of Liquid

1000 µL.

Maximum Volume for 1000 µL Micropipette

300 µg.

0.0003 g Equivalent in Micrograms

Should be level with the bottom of the meniscus.

Eye Level for Measuring Liquid in Graduated Cylinder

Meniscus.

Curve at Liquid’s Surface in Measurements

Data is spread out and inconsistent.

High Standard Deviation Meaning

Standard deviation.

Precision Measurement Tool

How close a measurement is to the true value.

False Statement About Precision

Red.

Color with Weakest Energy

P100 micropipette.

Best Tool for Measuring 0.08 mL

Higher absorbance = Higher concentration.

Absorbance and Concentration Relationship

False.

Fahrenheit Metric System Status

False.

Pounds in Metric System Status

By absorbing orange-red light, it reflects and transmits blue light.

Blue #1 Absorption Result Explanation

22 and 25°C

Room Temperature Range