Ap Biology- Chapter 7

Front 1

Light Microscopes

Back 1

Used by the first scientists, visible light is passed through the specimen and then through glass lenses. The lenses refract (bend) the light in such a way that the image o the specimen I magnified as it is projected into the eye, onto photograph film, or onto a video screen.

Front 2

Magnification

Back 2

The ratio of an object’s image to its real size.

Front 3

Resolving Power

Back 3

A measure of the clarity of the image, it is the minimum distance two points can be separated and still be distinguished as two separate points.

Front 4

Organelles

Back 4

Subcellular structures, usually too small to be resolved by a light microscope.

Front 5

Electron Microscope

Back 5

Instead of light, a beam of electrons is focused through the specimen or onto its surface. The resolving power is inversely related to the wavelength of radiation used, and electrons have wavelengths much shorter than the wavelengths of visible light.

Front 6

Transmission Electron Microscope

Back 6

Used to study the internal ultrastructure of cells by aiming an electron beam through a thin section of the specimen, but it uses electromagnets as lenses (instead of glass) to focus and magnify the image by blending the paths of the electrons.

Front 7

Scanning Electron Microscope

Back 7

Used to study, in detail, the surface of the specimen. The electron beam scans the surface of the sample, which is usually coated with a thin piece of gold. The beam excites electrons on the sample’s surface, and these secondary electrons are collected and focused onto a screen. The image appears to be three-dimensional.

Front 8

Cytology

Back 8

The study of cell structure.

Front 9

Biochemistry

Back 9

The study of the molecules and chemical processes of metabolism.

Front 10

Cell Fractionation

Back 10

To take cells apart, separating the major organelles so that their functions can be studied.

Front 11

Ultracentrifuges

Back 11

Powerful instruments used to fractionate cells, a merry-go-round for test tubes that can spin at various speeds.

Front 12

Homogenization

Back 12

The disruption of cells, cells are broken apart without damage being done to their organelles.

Front 13

Plasma Membrane

Back 13

A basic feature of all cells, the membrane that bounds them and functions as a selective barrier that allows sufficient passage of oxygen, nutrients, and wastes to service the entire volume of the cell.

Front 14

Cytosol

Back 14

The semifluid substance within the plasma membrane, it is found in all cells.

Front 15

Prokaryotic Cell

Back 15

A type of cell where the DNA is concentrated in a region called the nucleoid, but no membrane separates this region from the rest of the cell.

Front 16

Nucleiod

Back 16

An organelle in prokaryotic cells where the DNA is concentrated, it is separated from the rest of the cell.

Front 17

Eukaryotic Cell

Back 17

A type of cell that has a true nucleus, bounded by a membranous nuclear envelope.

Front 18

Cytoplasm

Back 18

The entire region (in all cells) between the nucleus and the plasma membrane. Where the organelles are suspended, in eukaryotic cells.

Front 19

Nucleus

Back 19

Contains most the genes in the eukaryotic cell and is enclosed by a nucleus envelope, separating it from the cytoplasm.

Front 20

Nuclear Envelope

Back 20

A double membrane, each a lipid bilayer with associated proteins. At the edges, the inner and outer membranes are fused. It regulates the entry and exit of certain large macromolecules and particles.

Front 21

Nuclear Lamina

Back 21

A netlike array of protein filaments that maintain the shape of the nucleus.

Front 22

Chromatin

Back 22

A fibrous material that DNA is organized along with proteins.

Front 23

Chromosomes

Back 23

Chromatic fibers that have coiled up into thick structures that can be discerned.

Front 24

Nucleolus

Back 24

The part of the nucleus where RNA is synthesized and assembled with proteins imported from the cytoplasm into the main compartments of ribosomes, called ribosomal subunits.

Front 25

Ribosomes

Back 25

Particles made of RNA and protein, the organelles that carry out protein synthesis, each is composed of two subunits.

Front 26

Free Ribosomes

Back 26

Ribosomes suspended in the cytosol. They make proteins that function within the cytosol, such as enzymes that catalyze the breakdown of sugar.

Front 27

Bound Ribosomes

Back 27

Ribosomes that are attached to the outside of the endoplasmic reticulum or nuclear envelope. They make proteins that are destined either for insertion in membranes, for packaging within certain organelles such as lysosomes, or for export form the cell (secretion).

Front 28

Endomembrane System

Back 28

The collection of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.

Front 29

Vescicles

Back 29

Sacs made of membrane.

Front 30

Endoplasmic Reticulum

Back 30

An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.

Front 31

Smooth ER

Back 31

That portion of the endoplasmic reticulum that is free of ribosomes. It synthesizes lipids, metabolism of carbohydrates, and the detoxification of drugs.

Front 32

Rough ER

Back 32

That portion of the endoplasmic reticulum studded with ribosomes.

Front 33

Glycoproteins

Back 33

Proteins covalently attached to a carbohydrate.
v. Transport Vesicle- A tiny membranous sac in a cell's cytoplasm carrying molecules produced by the cell.

Front 34

Golgi Apparatus

Back 34

An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum. It has a distinct polarity, with the membranes of the cisternae at opposite ends of the stack differing in thickness and molecular composition. It manufactures certain macromolecules.

Front 35

Lysosomes

Back 35

A membrane-enclosed bag of hydrolytic enzymes found in the cytoplasm of eukaryotic cells. It can hydrolyze proteins, polysaccharides, fats and nucleic acids. It maintains a low pH of around 5.

Front 36

Phagocystosis

Back 36

A type of endocytosis involving large, particulate substances.

Front 37

Autophagy

Back 37

A process where lysosomes use their hydrolytic enzymes to recycle the cell’s own organic material.

Front 38

Contractile Valcuoles

Back 38

Found in freshwater protests, they pump excess water out of the cell.

Front 39

Mitochondria

Back 39

Organelles in eukaryotic cells that serve as the site of cellular respiration, the catabolic process that generates ATP by extracting energy from sugars, fats, and other fuels with the help of oxygen.

Front 40

Chloroplasts

Back 40

Found only in plants and algae, they are the sites of photosynthesis and convert solar energy to chemical energy.

Front 41

Crista

Back 41

An infolding of the inner membrane of a mitochondrion that houses the electron transport chain and the enzyme catalyzing the synthesis of ATP.

Front 42

Mitochondrial Matrix

Back 42

The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the Krebs cycle.

Front 43

Plastids

Back 43

One of a family of closely related plant organelles, including chloroplasts, chromoplasts, and amyloplasts.

Front 44

Thylakoids

Back 44

Flattened sacs found inside chloroplasts that tend to be stacked.