BIO 103 LATEST UPDATED 2026 CORE QUESTIONS
AND ANSWERS SURE A+
✔✔Early Earth atmosphere - ✔✔Early Earth had little or no oxygen, so early life was
mostly anaerobic.
✔✔Cyanobacteria - ✔✔Bacteria that performed photosynthesis and helped oxygen
accumulate in Earth's atmosphere.
✔✔Great Oxygenation Event - ✔✔The rise of oxygen in Earth's atmosphere due to
photosynthetic organisms.
✔✔Why oxygen was a "pollution crisis" - ✔✔Oxygen was toxic to many anaerobic
organisms that evolved before oxygen was common.
✔✔Organelle - ✔✔A specialized structure inside a eukaryotic cell.
✔✔Nucleus - ✔✔The eukaryotic organelle that contains DNA.
✔✔Rough ER - ✔✔Endoplasmic reticulum with bound ribosomes; involved in folding
and processing proteins for membranes, secretion, or lysosomes.
✔✔Smooth ER - ✔✔Endoplasmic reticulum without ribosomes; involved in lipid
synthesis and other functions.
,✔✔Golgi apparatus - ✔✔Organelle that modifies, sorts, and ships proteins and lipids.
✔✔Cis Golgi - ✔✔The receiving side of the Golgi.
✔✔Trans Golgi - ✔✔The shipping side of the Golgi.
✔✔Vesicle - ✔✔A small membrane-bound sac used to transport materials in cells.
✔✔Lysosome - ✔✔Organelle containing digestive enzymes that break down worn-out
cell parts or molecules.
✔✔Endomembrane system - ✔✔A group of membranes and organelles that work
together to produce, process, and transport materials.
✔✔Path of secreted protein - ✔✔Nucleus to mRNA to bound ribosome on rough ER to
protein folding/modification to Golgi to vesicle to plasma membrane.
✔✔Bound ribosome - ✔✔A ribosome attached to rough ER; makes proteins for
secretion, membranes, or lysosomes.
✔✔Free ribosome - ✔✔A ribosome in the cytoplasm; makes proteins that usually
function in the cytosol.
✔✔Cytoskeleton - ✔✔Network of protein fibers that supports cell shape, movement, and
internal transport.
✔✔Microfilaments - ✔✔Actin filaments involved in cell shape and movement.
✔✔Microtubules - ✔✔Cytoskeletal fibers used for cell structure, vesicle transport, and
chromosome movement.
✔✔Intermediate filaments - ✔✔Cytoskeletal fibers that provide mechanical strength.
✔✔Motor proteins - ✔✔Proteins that move materials along cytoskeletal tracks.
✔✔Passive transport - ✔✔Movement across a membrane without energy, usually from
high concentration to low concentration.
✔✔Diffusion - ✔✔Movement of molecules from high concentration to low concentration.
✔✔Concentration gradient - ✔✔A difference in concentration across space or across a
membrane.
✔✔Facilitated diffusion - ✔✔Passive transport through a membrane protein.
, ✔✔Active transport - ✔✔Movement across a membrane against the concentration
gradient, from low concentration to high concentration, requiring energy.
✔✔High to low concentration - ✔✔Direction of passive transport down a concentration
gradient.
✔✔Low to high concentration - ✔✔Direction of active transport against a concentration
gradient.
✔✔ATP - ✔✔Adenosine triphosphate; the main energy-carrying molecule used for
cellular work.
✔✔ADP - ✔✔Adenosine diphosphate; lower-energy molecule formed when ATP loses a
phosphate.
✔✔ATP cycle - ✔✔ATP breaks down to ADP and phosphate to release energy, then
ADP is rebuilt into ATP using energy.
✔✔Three types of cellular work - ✔✔Chemical work, transport work, and mechanical
work.
✔✔Chemical work - ✔✔Building or breaking molecules in cells.
✔✔Transport work - ✔✔Moving substances across membranes, often against
gradients.
✔✔Mechanical work - ✔✔Movement, such as muscle contraction or movement of cell
parts.
✔✔Energy - ✔✔The ability to do work.
✔✔Kinetic energy - ✔✔Energy of motion.
✔✔Potential energy - ✔✔Stored energy due to position or structure.
✔✔Chemical energy - ✔✔Potential energy stored in chemical bonds.
✔✔First law of thermodynamics - ✔✔Energy cannot be created or destroyed, only
transformed.
✔✔Second law of thermodynamics - ✔✔Energy transformations increase disorder and
are not 100% efficient.
AND ANSWERS SURE A+
✔✔Early Earth atmosphere - ✔✔Early Earth had little or no oxygen, so early life was
mostly anaerobic.
✔✔Cyanobacteria - ✔✔Bacteria that performed photosynthesis and helped oxygen
accumulate in Earth's atmosphere.
✔✔Great Oxygenation Event - ✔✔The rise of oxygen in Earth's atmosphere due to
photosynthetic organisms.
✔✔Why oxygen was a "pollution crisis" - ✔✔Oxygen was toxic to many anaerobic
organisms that evolved before oxygen was common.
✔✔Organelle - ✔✔A specialized structure inside a eukaryotic cell.
✔✔Nucleus - ✔✔The eukaryotic organelle that contains DNA.
✔✔Rough ER - ✔✔Endoplasmic reticulum with bound ribosomes; involved in folding
and processing proteins for membranes, secretion, or lysosomes.
✔✔Smooth ER - ✔✔Endoplasmic reticulum without ribosomes; involved in lipid
synthesis and other functions.
,✔✔Golgi apparatus - ✔✔Organelle that modifies, sorts, and ships proteins and lipids.
✔✔Cis Golgi - ✔✔The receiving side of the Golgi.
✔✔Trans Golgi - ✔✔The shipping side of the Golgi.
✔✔Vesicle - ✔✔A small membrane-bound sac used to transport materials in cells.
✔✔Lysosome - ✔✔Organelle containing digestive enzymes that break down worn-out
cell parts or molecules.
✔✔Endomembrane system - ✔✔A group of membranes and organelles that work
together to produce, process, and transport materials.
✔✔Path of secreted protein - ✔✔Nucleus to mRNA to bound ribosome on rough ER to
protein folding/modification to Golgi to vesicle to plasma membrane.
✔✔Bound ribosome - ✔✔A ribosome attached to rough ER; makes proteins for
secretion, membranes, or lysosomes.
✔✔Free ribosome - ✔✔A ribosome in the cytoplasm; makes proteins that usually
function in the cytosol.
✔✔Cytoskeleton - ✔✔Network of protein fibers that supports cell shape, movement, and
internal transport.
✔✔Microfilaments - ✔✔Actin filaments involved in cell shape and movement.
✔✔Microtubules - ✔✔Cytoskeletal fibers used for cell structure, vesicle transport, and
chromosome movement.
✔✔Intermediate filaments - ✔✔Cytoskeletal fibers that provide mechanical strength.
✔✔Motor proteins - ✔✔Proteins that move materials along cytoskeletal tracks.
✔✔Passive transport - ✔✔Movement across a membrane without energy, usually from
high concentration to low concentration.
✔✔Diffusion - ✔✔Movement of molecules from high concentration to low concentration.
✔✔Concentration gradient - ✔✔A difference in concentration across space or across a
membrane.
✔✔Facilitated diffusion - ✔✔Passive transport through a membrane protein.
, ✔✔Active transport - ✔✔Movement across a membrane against the concentration
gradient, from low concentration to high concentration, requiring energy.
✔✔High to low concentration - ✔✔Direction of passive transport down a concentration
gradient.
✔✔Low to high concentration - ✔✔Direction of active transport against a concentration
gradient.
✔✔ATP - ✔✔Adenosine triphosphate; the main energy-carrying molecule used for
cellular work.
✔✔ADP - ✔✔Adenosine diphosphate; lower-energy molecule formed when ATP loses a
phosphate.
✔✔ATP cycle - ✔✔ATP breaks down to ADP and phosphate to release energy, then
ADP is rebuilt into ATP using energy.
✔✔Three types of cellular work - ✔✔Chemical work, transport work, and mechanical
work.
✔✔Chemical work - ✔✔Building or breaking molecules in cells.
✔✔Transport work - ✔✔Moving substances across membranes, often against
gradients.
✔✔Mechanical work - ✔✔Movement, such as muscle contraction or movement of cell
parts.
✔✔Energy - ✔✔The ability to do work.
✔✔Kinetic energy - ✔✔Energy of motion.
✔✔Potential energy - ✔✔Stored energy due to position or structure.
✔✔Chemical energy - ✔✔Potential energy stored in chemical bonds.
✔✔First law of thermodynamics - ✔✔Energy cannot be created or destroyed, only
transformed.
✔✔Second law of thermodynamics - ✔✔Energy transformations increase disorder and
are not 100% efficient.
