Biology Chapter 3 McGrawHill

cell

smallest unit of life that can function independently

cell theory

the ideas that all living things consists of cells, cells are the structural and functional units of life, and all cells come from preexisting cells.

Ribosome

a structure built of RNA and protein where mRNA anchors during protein synthesis.

Cell membrane

the boundary of a cell, consisting of proteins embedded in a phospholipid bilayer; also called the plasma membrane.

cytoplasm

the watery mixture that occupies much of a cell's volume; in eukaryotic cells, it consists of all materials, including organelles, between the nuclear envelope and the cell membrane.

cytosol

the fluid portion of the cytoplasm.

prokaryote

a cell that lacks a nucleus and other membrane-bounded organelles; bacteria and archaea

eukaryote

organism composed of one or more cells containing a nucleus and other membrane-bounded organelles.

Bacteria

one of two domains of prokaryotes

Archaea

one of two domains of prokaryotes

Eukarya

domain containing all eukaryotes

nucleoid

the part of a prokaryotic cells where the DNA is located.

cell wall

a rigid boundary surrounding cells of many prokaryotes, protists, plants, and fungi.

flagellum (flagella)

a long, whip-like appendage that a cell uses for motility

Organelle

a compartment of a eukaryotic cell that performs a specialized function.

phospholipid

molecule consisting of glycerol attached to two hydrophobic fatty acids and a hydrophilic phosphate group.

phospholipid bilayer

double layer of phospholipids that forms in water; forms the majority of a cell's membranes.

fluid mosaic

the two-dimensional structure of movable phospholipids and proteins that form biological membranes

endomembrane system

eukaryotic organelles that exchange materials in transport vesicles.

vesicle

a membrane-bounded sac that transports material within a cell

nucleus (cell)

the membrane-bounded sac that contains DNA in a eukaryotic cell

nuclear pore

a hole in the nuclear envelope.

nuclear envelope

the two membranes bounding a cell's nucleus

nucleolus

a structure within the nucleus where components of ribosomes are assembled

endoplasmic reticulum (ER)

interconnected, membranous tubules and sac in a eukaryotic cell.

rough endoplasmic reticulum

a ribosome-studded portion of the ER where secreted proteins are synthesized.

smooth endoplasmic reticulum

a portion of the ER that produces lipids and detoxifies poisons.

Golgi apparatus

a system of flat, stacked, membrane-bounded sacs that packages cell products for export.

lysosome

organelle in a eukaryotic cell that buds from the Golgi apparatus and enzymatically dismantles molecules. bacteria, and worn-out cell parts.

vacuole

membrane-bounded storage sac in a cell, especially the large central vacuole in a plant cell.

peroxisome

membrane-bounded sax that houses enzymes that break down fatty acids and dispose of toxic chemicals.

mitochondrion

organelle that houses the reactions of cellular respiration in eukaryotes.

crista (cristae)

fold of the inner mitochondrial membrane along which many of the reactions of cellular respiration occur.

chloroplast

organelle housing the reactions of photosynthesis in eukaryotes

cytoskeleton

framework of protein rods and tubules in eukaryotic cells

microfilament

component of the cytoskeleton; made of the protein actin

intermediate filament

component of the cytoskeleton; intermediate in size between a microtubule and a microfilament.

microtubule

component of the cytoskeleton; made of subunits of the protein tubulin

centrosome

part of the cell that organizes microtubules

cilium (cilia)

one of many short, movable protein projections extending from a cell.

tight junction

connection between two adjacent animal cells that prevents fluid from flowing past the cell.

anchoring (or adhering) junction

connection between two adjacent animal cells that anchors intermediate filaments in a single spot on the cell membrane.

gap junction

connection between two adjacent animal cells that allows cytoplasm to flow between them.

plasmodesma (plasmodesmata)

connection that allows cytoplasm to flow between adjacent plant cells.

transport proteins

Embedded in phospholipids bilateral creates passageways through which ions, glucose, and other polar substances pass into or out of the cell

Recognition proteins

carbohydrates attached to cell surface proteins serve as "name tags" that help the body's immune system recognize its own cells

Adhesión proteins

These membrane proteins enable cells to stick to one another

receptor proteins

bind to molecules outside the cell and trigger a response inside the cell, called signal transduction

amphipathic phospholipid bilayer

Phospholipids are amphipathic molecules. This means that they have a hydrophilic, polar phosphate head and two hydrophobic fatty acid tails.

animals extracellular matrix

animal cells release materials into the extracellular space, creating a complex meshwork of proteins and carbohydrates

One property that is present in cells in domain Eukarya but absent from those in domain Bacteria is

Membranous organelles

What chemical property of phospholipids is key to the formation of the cell membrane ?

The hydrophilic head and hydrophobic tails

Within a single cell, which of the following is physically the smallest?

phospholipid molecule

A human nerve cell that has an abnormal shape most likely has a defective

cytoskeleton

What type of cellular junction prevents stomach acid from leaking into the abdomen and digesting internal organs?

tight junctions

Light microscopes can reveal

True-color views of living or preserved cells, specimen must be transparent and thinly sliced, and two types are compound and confocal

Scanning Electron Microscope (SEM)

A microscope that uses an electron beam to scan the surface of a sample, coated with metal atoms, to study details of its topography.

Transmission Electron Microscope (TEM)

A microscope that uses an electron beam to study the internal structure of thinly sectioned specimens.

Electron microscopes can reveal

Greater magnification and resolution, and use electrons for microscope