Lab Safety and Equipment Quiz

Lab Safety and Equipment

• Wear safety goggles, no eating/drinking, know safety equipment locations (eyewash, fire extinguisher, first-aid kit), dispose of materials properly.

Common Lab Equipment

• Beaker: Used for mixing and heating liquids; not precise for measurements.
• Test Tube: Holds, mixes, or heats small amounts of substances.
• Graduated Cylinder: Accurately measures liquid volume.
• Pipette: Transfers small volumes of liquid. Different types exist.
• Bunsen Burner: Used for heating substances.
• Microscope: Used to view small specimens.
• Erlenmeyer Flask: Cone-shaped container for mixing liquids without spills; may hold reactions.
• Test Tube Rack: Holds test tubes upright during experiments.
• Micropipettes: Precisely measure and transfer very small liquid volumes, calibrated specifically.
• Pasteur/Plastic Pipettes: Used for transferring liquids in small, approximate amounts.
• Electronic Balance: Measures mass accurately.
• Weigh Boat: Holds substances while measuring mass on a balance.
• Forceps: Tweezers for handling small objects or substances.

Pipette Calibration and Accuracy

• Pipettes are precision instruments for accurate liquid volume measurements.
• Calibration ensures accuracy; methods vary by pipette type.
• Incorrect calibration leads to inaccuracies. Micropipettes require specific calibration procedures.
• Accuracy is paramount in scientific experiments.
• Regular maintenance and calibration are vital for accuracy, following manufacturer instructions.

Different Types of Pipettes

• Volumetric pipettes deliver a fixed volume of liquid precisely.
• Graduated pipettes allow measurement of various volumes.
• Micropipettes are designed for small volumes (microliters or nanoliters).
• Different pipettes have different scales.

Reading the Pipette

• Understand the pipette's scale (marked on the barrel).
• Volumetric pipettes have specific markings for their capacity.
• Graduated pipettes have markings across the barrel for variable measurements.
• Micropipettes often have a digital display for volume settings.
• Hold the pipette vertically to avoid parallax error.

Ensuring Accuracy When Reading a Pipette

• Align the liquid's meniscus with the scale mark.
• Submerge the pipette tip in the liquid. The meniscus's bottom curve should align.
• Avoid contacting the container's bottom to prevent errors and contamination.
• Some pipettes have specific temperature ranges and may require compensation.
• Consult the pipette's instruction manual for handling.
• Pay close attention to volume settings on micropipettes.

Importance of Parallax Error

• Parallax error occurs when the observer's eye isn't directly aligned with the scale.
• This misalignment leads to inaccurate measurements; visual shifting of the meniscus.
• To avoid parallax, position your eye directly above the meniscus.

Nature of Life

Bioregions

• Bioregions are areas with unique climates, vegetation, and animals.
• Examples include deserts, forests, grasslands, and tundras.

Impact of Invasive Species

• Invasive species are non-native organisms that disrupt ecosystems by outcompeting natives thereby reducing biodiversity.
• Zebra mussels in the Great Lakes and kudzu in the southeastern U.S. are examples.

Characteristics of Living Things

• Cellular Organization: Living organisms are composed of cells.
• Metabolism: Organisms use energy for growth and maintenance (anabolism/building up and catabolism/breaking down).
• Homeostasis: Maintaining stable internal conditions.
• Growth and Development: Organisms progress through life stages according to genetic instructions.
• Reproduction: The ability to create offspring.
• Response to Stimuli: Organisms react to environmental changes.
• Adaptation Through Evolution: Changes over generations for survival.

Homeostasis Examples

• Temperature Regulation: e.g., sweating (cooling) or shivering (warming).
• Blood Sugar Levels: Regulated by insulin and glucagon.

Pill Bug Experiment

• Investigated pill bug (isopod) behavior in different environments.
• Hypotheses might focus on moisture preferences or light exposure.
• Data collection involved observing pill bug movement/responses.

Ecology

Climate Change

• Climate change involves significant global temperature and weather pattern changes.
• Causes include greenhouse gas emissions, deforestation, and fossil fuel use.
• Impacts include rising sea levels, habitat loss, and altered species distributions.

Food Webs and Energy Flow

• Food webs show complex feeding relationships between organisms.
• Energy enters ecosystems through photosynthesis, flowing from Producers → Primary Consumers → Secondary Consumers → Tertiary Consumers.

Keystone Species

• Keystone species have a large impact on their environment, disproportionate to their abundance.
• Examples include sea otters (regulating sea urchin populations) and bees (pollination).

Ocean Acidification

• Ocean acidification is the ongoing decrease in the pH of the Earth's oceans, caused by the absorption of excess atmospheric carbon dioxide from the burning of fossil fuels.

Niche

• Niche describes an organism's role in its environment, including its interactions with other species, habitats, and resources it uses.

Cells

Cell Membranes

• Cell membranes are selectively permeable barriers enclosing cell contents.
• Primarily composed of a phospholipid bilayer with embedded proteins.
• Phospholipids have a hydrophilic head and two hydrophobic tails.
• This structure controls molecule passage.
• Membrane proteins perform various functions (transport, signaling, support).

Selective Permeability

• Cell membranes have selective permeability, allowing certain molecules through.
• Factors influencing permeability include size, charge, and solubility.

Cell Transport

• Passive Transport: Movement of molecules without energy input (diffusion, osmosis).
• Active Transport: Movement of molecules against concentration gradients, requiring energy (sodium-potassium pump).

Types of Diffusion

• Simple Diffusion: Small, nonpolar molecules directly pass through the membrane (O2, CO2).
• Facilitated Diffusion: Larger or polar molecules use membrane proteins to move.
• Osmosis: Water diffuses across a selectively permeable membrane.

Osmosis and Diffusion

• Osmosis is the movement of water across a selectively permeable membrane from higher to lower water concentration.
• Diffusion is the movement of particles from higher to lower concentration.
• Both are passive transport mechanisms.

Tonicity (Hypotonic, Hypertonic, Isotonic)

• Tonicity describes the relative solute concentration in a solution compared to the cell.
• Hypotonic solutions: Lower solute concentration than the cell. Water moves into the cell, causing swelling (cell lysis in animal cells).
• Hypertonic solutions: Higher solute concentration than the cell. Water moves out of the cell, causing shrinking (crenation in animal cells).
• Isotonic solutions: Same solute concentration as the cell. Water movement is balanced, maintaining cell shape.

Effect of Tonicity on Different Cell Types

• Animal cells: Isotonic environments are crucial for maintaining cell shape and function.
• Plant cells: Hypotonic environments are ideal for maintaining turgor pressure, vital for support. Hypertonic environments lead to plasmolysis (separation of cell membrane from cell wall).

Biomolecules

• Carbohydrates: Composed of carbon, hydrogen, and oxygen. Provide energy.
• Proteins: Composed of amino acids. Essential for structure, function, and regulation.
• Lipids: Composed of carbon, hydrogen, and oxygen. Store energy, act as insulation, and make up cell membranes.
• Nucleic Acids: Composed of nucleotides. Store genetic information (DNA, RNA).

Study Tips

• Review key concepts and definitions.
• Create flashcards for important vocabulary.
• Conduct experiments or simulations for reinforcement.
• Discuss concepts with classmates.

Test your knowledge on lab safety precautions and common laboratory equipment. This quiz covers essential practices that ensure a safe lab environment, as well as the function of various tools used in scientific experiments. Perfect for students learning about laboratory protocols and bioregions!