Chapter 4 Flashcards
plasma membrane
separates internal contents of cell from external environment. contain cilia, flagellum, and microvilli. has polar heads and 2 hydrophobic tails. Cholesterol strengthens the membrane and protects against temp. Glycolipids for coating of sugar on cell surface
nucleus
largest structure in cell; contains genetic material and a fluid called nucleoplasm.
cytoplasm
cellular contents between plasma membrane and nucleus. includes cytosol, organelles, and inclusions.
cytosol
viscous fluid in the cytoplasm
inclusions
large diverse group of molecules not bound by membranes. (ex: pigment, glycogen, triglycerides)
general cell functions
maintain integrity and shape of cell, obtain nutrients and form chemical building blocks, dispose of waste. some cells go through division
integral proteins
embedded within lipid bilayer and extend across. often glycoproteins with carb portion
peripheral proteins
attached loosely to surface of lipid bilayer
passive transport
does not require energy and moves substances down their concentration gradients. includes diffusion and osmosis
osmosis
travel of water into or out of the cell.
tonicity
ability of a solution to change the volume or pressure of the cell by osmosis
isotonic
no net movement of water; in the body the cell and outside have 0.9% NaCl
hypotonic
solution with lower solute than cell. Moves water into the cell and ma cause lysis or rupturing
hypertonic
solution with higher concentration of solutes than cell. Water moves out and causes cell to crenate or shrink
active transport
require energy, can move substances up its concentration gradient
ion pumps
active transport proteins that move ions across membrane. Helps cell maintain internal concentration of ions.
vesicular transport
requires vesicles and energy. exocytosis and endocytosis
exocytosis
vesicle fuses with membrane and releases substances out of cell
endocytosis
vesicle encloses material outside cell and fuses with membrane to bring into cell
phagocytosis
when a cell engulfs particle external to cell. only in a few cell types like white blood cells
pinocytosis
internalization of drops of interstitial fluid. multiple vesicles form and solutes are taken into cell. performed by most cells
endoplasmic reticulum
separates fluid within structure from cytosol, extends from nuclear envelope, point of attachment for ribosomes, and point for insertion of enzymes.
rough er
protein and peroxisome production, plentiful in cells producing a lot of protein
smooth er
synthesis, transport, and storage of lipids, carb metabolism, detox. plentiful in testes and liver
Golgi apparatus
composed of saclike structures called cisternae. “warehouse of the cell. functions include modification, packaging, and sorting proteins, transport of material from cis face to trans face, and formation of secretory vesicles and lysosomes
lysosomes
small sacs that contain digestive enzymes from the Golgi. digest unneeded substances and contents of endocytosed vesicles
peroxisomes
pinched off vesicles from rough er. Smaller than lysosomes and contain oxidative enzymes. serve in detoxification by producing hydrogen peroxide. engage in beta oxidation of fatty acid. most abundant in liver
mitochondria
aerobic cellular respiration and complete digestion of fuel molecules to make atp
ribosomes
contain protein and ribonucleic acid. have a large (with e, p, and a sites) and small subset. bound ribosomes make proteins for plasma membrane, export, or lysosomes. free ribosomes make all other proteins
cytoskeleton
plays role in intracellular support, organization of organelles, cell division, and movement of materials. also anchors proteins in plasma membrane. includes microfilaments, intermediate filaments, and microtubules.
centrosome
close proximity to nucleus and contains pair of perpendicularly oriented cylindrical centrioles. organizes microtubules within cytoskeleton and aids in cell division
proteasomes
large barrel-shaped complexes that digest proteins with a ubiquitin tag.
cilia
found on surface of specific cells such as in the respiratory tract to move substances
flagella
propels entire cell
microvilli
microscopic extensions from surface of plasma membrane. supported by microfilaments and increase surface area to absorb nutrients.
nuclear envelope
double phospholipid membrane enclosing nucleus. contains nucleoplasm and is continuous with rough er. Contains passageways called nuclear pores.
Cell division
necessary for development, tissue growth and repair, and replacement of old cells. mitosis occurs in somatic cells and meiosis in sex cells.
