Organelles
Identify four components of all living cells.
DNA, Ribosome, Membrane, Cytoplasm
Identify the two components to consider when evaluting cell size.
Surface area and volume
Identify the component of the plasma membrane that keeps the bilayer fluid in fluctuating temperatures.
Cholesterol
Identify three substances the plasma membrane is permeable to.
Answers can vary (O2, CO2, N2, Water, Vitamin A, D, E, K, etc.)
Identify the three main pieces of evidence for the endosymbiotic theory.
Mitochondria/Chloroplast = Double membrane, independent DNA, independent ribosomes
Why is the nuclear envelope porous?
To allow the exit of mRNA
Cell A has a SA:V ratio of 6:3, Cell B has a ratio of 4:1. Which cell will be more efficient at exchanging material with the environment?
Cell B (larger ratio)
Describe the difference between integral and peripheral proteins.
Integral (integrins) are found within the membrane, peripheral are on either the interior/exterior surface of the membrane
Describe the function of transport proteins (include polarity in your answer).
Provide a hydrophilic channel for polar substances so they can pass through the nonpolar, hydrophobic tails
Describe the endosymbiotic theory in terms of the chlorplast.
Non-photosynthetic eukaryote ingested a photosynthetic prokaryote to form a mutually beneficial relationship
Describe the difference between chromosomes and chromatin.
Chromatin: Unwound DNA, Chromosomes: Linear packed DNA prior to division
Identify the component of plasma membranes that will result in an increase in surface area without increasing volume.
Microvilli
Define glycocalyx and describe it's main function.
All carbohydrates on a cells surface; cell identification
Define osmolarity and describe how it influences the movement of water.
Osmolarity = solutions total solute concentration; water will move to the area with higher osmolarity
Describe the endosymbiotic theory in terms of the mitchondria.
Non-aerobic eukaryote ingested an aerobic prokaryote to form a mutually beneficial relationship
Why is the lysosome a membrane-bound organelle? Describe what might happen if the membrane bursts.
Lysosome contains hydrolytic enzymes that are acidic; if the membrane ruptures, the enzymes will spill into the cytosol, making it acidic
Evaluate the following SA:V ratios and identify which cell will be the most and least efficient at material exchange:
Cell 1: 10:7
Cell 2: 6:1
Cell 3: 4:2
Cell 4: 8:3
Most efficient: Cell 2, Least efficient: Cell 1
Identify the structural component of a phospholipid that prevents the membrane from freezing together.
Kink (double C bond) in the unsaturated fatty acid tail
Describe how transport protein specificity can be limiting to transportation.
If all proteins are occupied, material concentration can continue to increase, but the rate of transportation will not
Describe how eukaryotic cells compartmentalize and how this benefits the cell.
Membrane bound organelles increase cell efficiency
Describe the difference between the cis and trans face of the golg apparatus.
Cis face is where transport vesicles arrive at the golgi; trans face is where secretory vesicles will leave ("bud off") the golgi
A spherical bacterial cell has a radium of 3 micrometers; a human egg cell has a radius of 100 micrometers. Which cell is going to be more efficient at material exchange with the environment? Why?
Bacterial cell = larger SA:V ratio
Identify a place in the human body where plasma membranes would contain large amounts of microvilli.
Intestines/Kidneys
Describe the electrochemical gradient across a plasma membrane in regards to sodium and potassium.
NA+ is attracted inside the cell to the negative cytoplasm; K+ flows out of cell along its concentration gradient
Why are lethal injections a potassium solution?
Influx of extracellular K+ disrupts the concentration gradient, stopping the flow of the Na+/K+ pump, therefore disrupting the electrochemical gradient that cardiac muscle depends on