Cell Theory
Name the three main principles of the cell theory.
(1) Cells are the basic unit of life. (2) Cells perform all life functions. (3) Cells arise from existing cells.
Which organelle contains the cell’s DNA in eukaryotic cells?
Nucleus
What is the basic structural unit of the cell membrane (name the molecule and the arrangement)?
Phospholipid Bilayer
Define diffusion and state the direction molecules move relative to concentration gradients.
random movement of molecules from high to low concentration until equilibrium.
What is an independent and dependent variable?
Independent - What the experimenter is changing
Dependent - What is being measured
Explain why Robert Hooke called what he saw “cells.”
Hooke saw tiny box-like compartments in cork that resembled jail “cells.”
What is the main function of ribosomes?
Make (synthesize) proteins
Which part of a phospholipid is hydrophilic and which part is hydrophobic?
Phosphate head is hydrophilic; fatty acid tails are hydrophobic.
What is osmosis? How is it different from simple diffusion?
Osmosis: diffusion of water across a semipermeable membrane; diffusion can refer to any molecule and may not require a membrane.
What is a control variable? Give 3 controls from our Bean lab experiment.
Variables that stay the same.
1. Time
2. Water (if testing sunlight)
3. Sunlight (if testing water amount
What are the 2 main differences between Prokaryotic and Eukaryotic Cells
1. Nucleus
2. Membrane Bound Organelles
Compare the roles of the rough ER and the Golgi apparatus in protein production and processing.
Rough ER: ribosomes attached. makes, modifies, and transports proteins to Golgi
Golgi: receives vesicles from ER, further modifies, sorts, and ships proteins to final destinations.
List three other types of molecules found in the membrane and give one function for each.
Cholesterol: stabilizes membrane fluidity.
Carbohydrates: cell identification and signaling.
Proteins: transport (channels/pumps)
Describe facilitated diffusion and explain the difference between channel proteins and carrier proteins.
Facilitated diffusion: passive movement of molecules down a gradient through membrane proteins.
Channel proteins form pores for ions or water
carrier proteins bind specific molecules and change shape to transport them.
What are the two types of data you can collect? Name examples of each.
Qualitative: Descriptions without using numbers like color change, if something taste good, etc.
Quantitative: Numerical measurements like length, height, mass, etc.
Name 3 differences between a plant and animal cell
1. Cell Wall
2. Chloroplast
3. Central Vacuole vs Many small Vacuoles
Describe three differences between mitochondria and chloroplasts
1. Chloroplast are only found in Plant Cells
2. Chloroplast turn glucose into energy, Mitochondria turn sunlight energy into glucose
3. Mitochondria does not have chlorophyll pigment to receive light energy
Explain how membrane proteins and carbohydrates contribute to selective permeability and cell recognition.
Proteins form channels/carriers that selectively allow molecules through.
Carbohydrates serve as markers for cell recognition and signaling, affecting which molecules or cells interact.
Define hypotonic, isotonic, and hypertonic solutions and describe one effect each has on an animal cell.
Hypotonic: lower solute outside cell → water enters → animal cell may swell and burst.
Isotonic: equal solute → no net water movement → cell stable.
Hypertonic: higher solute outside → water leaves → animal cell shrivels.
What is the difference between a Law and Theory?
Theory - incorporates many well supported hypotheses that enable scientist to make accurate predictions.
Law - Concise, specific descriptions of how some aspects of the natural world are expected to behave in a certain situation.
Name an example of a Prokaryotic Cell
Bacteria/Archaea
Explain how the cytoskeleton contributes to both cell shape and intracellular transport; name the three cytoskeletal fibers and one role for each.
Cytoskeleton provides structure and transport.
Microtubules: organelle movement
Microfilaments: maintain shape.
Intermediate filaments: structural support, anchor organelles.
Describe how cholesterol affects membrane fluidity at high and low temperatures and explain why this is important for cell function.
Cholesterol reduces membrane fluidity at high temperatures by restraining phospholipid movement and prevents membranes from becoming too rigid at low temperatures by preventing tight packing, maintaining optimal membrane function across temperatures.
What type of active transport is endocytosis and exocytosis? What does each mean
Bulk Transport.
Endocytosis - using vesicles to move very large substances into the cell.
Exocytosis- using vesicles to move very large substances out of the cell
What were the 4 Scientific attitudes and why are each important
Open-mindedness, skepticism, creativity, curiosity