44 terms

Ch #4: Tour of the Cell

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cell junction
Contact points between the plasma membranes of tissue cells
cell theory
all living things are made of cells, that cells are the basic units of organisms, and that cells come only from existing cells
central vacuole
A large vacuole that rests at the center of most plant cells and is filled with a solution that contains a high concentration of solutes
chloroplasts
(in green plant cells) a plastid that contains chlorophyll and in which photosynthesis takes place.
chromatin
Substance found in eukaryotic chromosomes that consists of DNA tightly coiled around histones
chromosomes
A doubled rod of condensed chromatin; contains DNA that carries genetic information.
cilia
Hairlike projections that extend from the plasma membrane and are used for locomotion
cristae
Infoldings of the inner membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP.
cytoplasm
A jellylike fluid inside the cell in which the organelles are suspended
cytoskeleton
A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement
cystosol
liquid part of cytoplasm
electron microscope
microscope that forms an image by focusing beams of electrons onto a specimen
endomembrane system
A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.
endoplasmic reticulum
A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another.
eukaryotic cells
larger more complex, contains dozens of structures and are highly specialized, have nucleus,
extracellular matrix
Non-living material that surrounds living cells
flagella
A long cellular appendage specialized for locomotion, formed from a core of nine outer doublet microtubules and two inner single microtubules, ensheathed in an extension of plasma membrane.
fluid mosaic
The currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of individually inserted protein molecules drifting laterally in a fluid bilayer of phospholipids.
golgi apparatus
A system of membranes that modifies and packages proteins for export by the cell
grana
A stacked portion of the thylakoid membrane in the chloroplast. Grana function in the light reactions of photosynthesis
light microscope
An optical instrument with lenses that refract (bend) visible light to magnify images of specimens.
lysosome
an organelle in the cytoplasm of eukaryotic cells containing degradative enzymes enclosed in a membrane.
magnification
An increase in the apparent size of an object
matrix
Innermost compartment of the mitochondrion
microtubules
A hollow rod composed of tubulin proteins that makes up part of the cytoskeleton in all eukaryotic cells and is found in cilia and flagella.
mitochondria
An organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP
nuclear envelope
Double membrane perforated with pores that control the flow of materials in and out of the nucleus.
nucleoid
A dense region of DNA in a prokaryotic cell.
nucleolus
Found inside the nucleus and produces ribosomes
nucleus
A membrane‐bound organelle in eukaryotic cells functioning to maintain the integrity of the genetic material and, through the expression of that material, controlling and regulating cellular activities.
organelles
A tiny cell structure that carries out a specific function within the cell.
phospholipids
A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.
phospholipid bilayer
Plasma membrane layers composed of phospholipid molecules arranged with polar heads facing the outside and nonpolar tails facing the inside.
plasma membrane
A selectively-permeable phospholipid bilayer forming the boundary of the cells and organelles
prokaryotic cells
Small, simple, no nucleus, no membrane-bound organelles, single loop of DNA (nucleosome), no cellulose, cytoplasm, cell membrane, cell wall (made of carbs), sometimes have cilia or flagella (movement).
resolving power
the ability of an optical instrument to show two objects as separate
ribosomes
Cytoplasmic organelles at which proteins are synthesized.
rough ER
A network of interconnected membranous sacs in a eukaryotic cell's cytoplasm; covered with ribosomes that make membrane proteins and secretory proteins.
scanning electron microscope
a microscope that produces an enlarged, three-dimensional image of an object by using a beam of electrons rather than light
smooth er
Synthesis of lipids, phospholipids and steroid sex hormones-help detoxify drugs and poisons (liver cells).
stroma
The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.
transmission electron microscope
microscope where image is derived from electrons that have passed through it. (resolution is 1000X better than optical) used to study the internal structure of thin sections of cells
transport vesicles
Move materials between organelles or between organelles and the plasma membrane.
vacuoles
Cell organelle that stores materials such as water, salts, proteins, and carbohydrates