CELL BIOLOGY STUDY GUIDE WITH COMPLETE
SOLUTION!!
Cell Structure and Function –
Seven Key Cellular Functions: Cells perform specialized roles including
movement, electrical conductivity, nutrient absorption, secretion, excretion,
respiration, and reproduction.
Nucleus: Controls genetic material and cell division; contains DNA (similar to the
yolk inside an egg).
Ribosomes: Complexes of RNA and protein that float in the cytoplasm;
responsible for synthesizing proteins and preparing them for transport or secretion.
Endoplasmic Reticulum (ER): Involved in producing and transporting proteins and
lipids for most organelles; acts like a manufacturing system within the cell.
Golgi Apparatus: Modifies, sorts, and packages proteins into vesicles for transport
inside or outside the cell; functions like the cell’s “refinery” or “traffic controller.”
Lysosomes: Contain enzymes that break down and recycle waste materials and
dead cell components; can digest their own cell contents when ruptured, a process
called autodigestion.
Mitochondria: The “powerhouse” of the cell; produce ATP through metabolism of
carbohydrates, lipids, and amino acids; can grow and self-replicate to sustain
cellular life.
Cytoskeleton: A structural framework of fibers that maintains cell shape, provides
support, and enables movement; acts as the cell’s “bones and muscles.” Cilia assist
with movement.
Plasma Membrane: Composed of lipids and proteins, primarily a phospholipid
bilayer that maintains membrane integrity and regulates entry and exit of
substances.
, Barrier Function: The phospholipid layer prevents water-soluble molecules from
freely entering the cell.
Cell Types and Transport Mechanisms
Prokaryotic Cells: Single-celled organisms lacking a nucleus and membrane-bound
organelles (e.g., bacteria, cyanobacteria, rickettsia).
Eukaryotic Cells: Have a defined nucleus and complex internal structures;
generally larger and more advanced.
Cellular Receptors: Protein molecules located on the membrane, cytoplasm, or
nucleus that bind specific signaling molecules (ligands).
Types of Receptors: Plasma membrane, channel-linked, and non-channel-linked
receptors.
Passive Transport: Movement of substances across membranes without energy
input; molecules move down their concentration gradient.
Diffusion: Molecules move from areas of high to low concentration.
Concentration Gradient: Difference in the amount of a substance across a space.