Chapter 3: Cells

interstitial fluid

term given to extracellular fluid not contained within blood vessels

integral protein

protein that is embedded in the cell membrane

channel protein

an integral protein in the cell membrane that selectively allows particular materials, such as certain ions, to pass into or out of the cell.

peripheral protein

proteins that are typically found on the inner or outer surface of the lipid bilayer but can also be attached to the internal or external surface of an integral protein.

cell recognition proteins

protein that marks a cell’s identity so that it can be recognized by other cells

receptor

a type of recognition protein that can selectively bind a specific molecule outside the cell, and this binding induces a chemical reaction within the cell.

ligand

the specific molecule that binds to and activates a receptor, some also serve as ion channels.

glycoprotein

a protein that has carbohydrate molecules attached, which extend into the extracellular matrix, aid in cell recognition.

glycocalyx

the carbohydrates that extend from membrane proteins and even from some membrane lipids collectively.

isotonic solutions

solutions that have equal concentrations of solutes

hypertonic solution

has higher concentration of solute than another solution

hypotonic solution

a solution that has a lower concentration of solute as compared to another solution

dynamic equilibrium

a net, uniform distribution of molecules in a space. Molecules are still in motion, but overall, they are equally distributed and not clumping together to form areas of higher concentration.

osmotic pressure

the lowest pressure that can be applied to a solution to prevent solute flow across the semipermeable membrane

filtration

uses a hydrostatic pressure gradient that pushes the fluid (and solutes within it) from a higher pressure area to a lower pressure area

endocytosis

(bringing into the cell) process of a cell ingesting material by engulfing it in a portion of it’s membrane, and then pinching off that portion of the membrane. Often brings in materials to be broken down or digested.

Phagocytosis

(eating) endocytosis of large particles to be digested by the cell, often in regard to unwanted matter or invading bacterial cells within the body.

Pinocytosis

(drinking) brings fluid containing dissolved substances into a cell through membrane vesicles.

exocytosis

(removing from the cell) process of a cell exporting material using vesicular transport

cytosol

jelly-like substance within cells

cytoplasm

made up of the organelles and cytosol together

endomembrane system

made up of the endoplasmic reticulum, golgi apparatus, and vesicles

endoplasmic reticulum

system of channels that is continuous with the nuclear membrane covering the nucleus and composed of the same lipid bilayer material.

ribosome

organelle that is responsible for protein synthesis, found covering rough ER.

lysosome

contains enzymes that break down and digest unneeded cellular components, such as damaged organelles via autophagy

autophagy

“self-eating” is the process of a cell digesting its own structure

autolysis

in the case of damaged or unhealthy cells, lysosomes can be triggered to release their digestive enzymes into the cytoplasm of the cell, killing the cell. Self destruction.

peroxisome

a membrane-bound cellular organelle that contains mostly enzymes, functions include lipid metabolism and chemical detoxification, neutralizes poisons such as alcohol.

cytoskeleton

network of protein fibers within cells that provide structure, support and shape while also enabling movement and transport

microfilaments

thin, flexible filaments made of actin proteins that support cell shape, enable movement, and assist in creation of cleavage furrow during cell division

microtubules

hollow tubes made of tubulin proteins that serve as tracks for the movement of organelles and vesicles, form spindle fibers during cell division, support cell shape, essential for cilia and flagellum.

intermediate filaments

rope-like fibers that provide mechanical strength, stabilize cell structures, and help maintain shape of nucleus and other organelles.

chromatin

threads within nucleus composed of DNA and associated proteins

histone proteins

DNA is wrapped around these proteins along chromatin threads.

nucleosome

single, wrapped DNA-histone complex

chromosome

condensed form of chromatin, composed of DNA and proteins.

helicase

enzyme that helps separate DNA strands during replication

DNA polymerase

brings in the correct bases to complement the template strand, creating a new strand base by base.

spliceosome

structure composed of proteins and other molecules that removes the non-coding parts of mRNA after synthesis.

intron

removed segment of mRNA that does not code for any proteins

exon

the part of the RNA that remains after splicing