U2 Chapter 6: A Tour of the Cell Flashcards

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1
Q

Light Microscope (LM)

A

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 of the specimen is magnified as it is projected into the eye or into a camera

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2
Q

Magnification

A

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

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3
Q

Resolution

A

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

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4
Q

Organelles

A

The membrane-enclosed structures within eukaryotic cells

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5
Q

Electron Microscope (EM)

A

Focuses a beam of electrons through the specimen or onto its surface

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6
Q

Scanning Electron Microscope (SEM)

A

Useful for detailed study of the topography of a specimen where the electron beam scans the surface of the sample, usually coated with a thin film of gold
- the result is an image of the specimen’s surface that appears 3D

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7
Q

Transmission Electron Microscope (TEM)

A

Used to study the internal structure of cells where the TEM aims an electron beam through a very thin section of the specimen, much as a light microscope aims light through a sample on a slide

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8
Q

Cell Fractionation

A

Technique for studying cell structure and dunction which takes cells apart and separates major organelles and other subcellular structures from one another

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9
Q

Differential Centrifugation

A

The piece of equipment that is used for this task is the centrifuge, which spins test tubes holding mixtures of disrupted cells at a series of increasing speeds

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10
Q

Cytosol

A

Semifluid and jellylike substance where subcellular components are suspended

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11
Q

Eukaryotic Cell

A

Most of the DNA is in an organelles called the nucleus, which is bounded by a double membrane

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12
Q

Prokaryotic Cell

A

The DNA is concentrated in a region that is not membrane-enclosed nucleoid

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13
Q

Cytoplasm

A

Interior in all cells
- for eukaryotic cells, this term refers only to the region between the nucleus and the plasma membrane

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14
Q

Nucleus

A

Contains most of the genes in the eukaryotic cell (some genes are located in mitochondria and chloroplasts)

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15
Q

Nuclear Envelope

A

Encloses the nucleus, separating its contents from the cytoplasm

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16
Q

Nuclear Lamina

A

A netlike array of protein filaments (in animal cells, called intermediate filaments) that maintains the shape of the nucleus by mechanically supporting the nuclear envelope

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17
Q

Chromosomes

A

Structures that carry the genetic information that DNA units are organized into

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18
Q

Chromatin

A

Complex DNA and proteins making up chromosomes

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19
Q

Nucleolus (plural for nucleoli)

A

Appears through the electron microscope as a mass of densely stained granules and fibers adjoining part of the chromatin

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20
Q

Ribosomes

A

Complexes made of ribosomal RNAs and proteins, are the cellular components that carry out protein synthesis

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21
Q

Endomembrane System

A

Different membrane-bounded organelles of the eukaryotic cell, which includes the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, lysosomes, various kinds of vesicles and vacuoles, and the plasma membrane

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22
Q

Vesicles

A

Sacs made of membrane for membrane transfer segments

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23
Q

Endoplasmic Reticulum (ER)

A

Extensive network of membranes that it accounts for more than half the total membrane in many eukaryotic cells

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24
Q

Smooth ER

A

Named because its outer surface lacks ribosomes

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25
Q

Rough ER

A

Studded with ribosomes on the outer surface of the membrane and thus appears rough through the electron microscope

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26
Q

Transport Vesicles

A

Vesicles in transit from one part of the cell to another

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27
Q

Golgi Apparatus

A

After leaving the ER, many transport vesicles travel to the GB where it is a warehouse for receiving, sorting, shipping, and even some manufacturing
- products of the ER, such as proteins, are modified and stored and then sent to other destinations

28
Q

Lysosome

A

Membranous sac of hydrolytic enzymes that many eukaryotic cells use to digest (hydrolyze) macromolecules
- lysosomal enzymes work best in the acidic environment found in lysosomes

29
Q

Phagocytosis

A

Amoebas and many other unicellular protists eat by engulfing smaller organisms or food particles

30
Q

Vacuoles

A

Large vesicles derived from the endoplasmic reticulum and Golgi apparatus
- vacuolar membrane is selective in transporting solutes; as a result, the solution inside a vacuole differs in composition from the cytosol

31
Q

Types of Vacuoles

A
  • food vacuoles: formed by phagocytosis, have already been mentioned
  • contractile vacuoles: many unicellular protists living in fresh water have this to pump excess water out of the cell, thereby maintaining a suitable concentration of ions and molecules inside the cell
  • central vacuoles: in mature plant cells and developed by the coalescence of smaller vacuoles where the solutions called the cell sap is the main repository of inorganic ions (including potassium and chloride)
32
Q

Mitochondria

A

Sites of cellular respiration, the metabolic process uses oxygen to drive the generation of ATP by extracting energy from sugars, fats, and other fuels

33
Q

Chloroplasts

A

Found in plants and algae, are the sites of photosynthesis where chloroplasts convert solar energy to chemical energy by absorbing sunlight and using it to drive the synthesis of organic compounds such as sugars from carbon dioxide and water

34
Q

Endosymbiont Theory

A

States that an early ancestor of eukaryotic cells (a host cell) engulfed an oxygen using non-photosynthetic prokaryotic cell and eventually the engulfed cell formed a relationship with the host cell in which it was enclosed, becoming an endosymbiont (a cell living within another cell)

35
Q

Mitochondrial Matrix

A

Enclosed by the inner membrane, the matrix contains many different enzymes as well as the mitochondrial DNA and ribosomes
- enzymes in the matrix catalyze some of the steps of cellular respiration
- proteins that function in respiration, including the enzyme that makes ATP are built into the inner membrane

36
Q

Thylakoids

A

Inside the chloroplasts, membranous system in the form of flattened interconnected sacs

37
Q

Granum (plural, grana)

A

Thylakoids are staked like poker chips, granum is each individual stack

38
Q

Stroma

A

The fluid outside the thylakoids and contains the chloroplast DNA and ribosomes as well as many enzymes

39
Q

Plastids

A

Pivotal subcellular organelles that have evolved to perform specialized functions in plant cells, including photosynthesis and the production and storage of metabolites
- Amyloplast: a colorless organelle that stores starch (amylose) particularly in roots and tubers
- Chromoplast: has pigments that give fruit and flowers their orange and yellow hues

40
Q

Peroxisome

A

A specialized metabolic compartment bounded by a single membrane
- Contains enzymes that remove hydrogen atoms from various substrates and transfer them to oxygen (O2), producing hydrogen peroxide (H2O2) as a by-product

41
Q

Cytoskeleton

A

A network of fibers extending throughout the cytoplasm

42
Q

Motor Protein

A

A class of molecular motors that can move along the cytoplasm of animal cells. They convert chemical energy into mechanical work by the hydrolysis of ATP. Flagellar rotation, however, is powered by a proton pump

43
Q

Microtubules

A

Hollow rods constructed from globular proteins called tubulins

44
Q

Centrosome

A

Microtubules grow out from this and it is a region that is often located near the nucleus

45
Q

Centrioles

A

Within the centrosome as a pair, each composed of nine sets of triplet microtubules arranged in a ring

46
Q

Flagella

A

A motility organelle that enables movement and chemotaxis. Bacteria can have one flagellum or several, and they can be either polar (one or several flagella at one spot) or peritrichous (several flagella all over the bacterium)

47
Q

Cilia

A

To move water relative to the cell in a regular movement of the cilia. This process can either result in the cell moving through the water, typical for many single-celled organisms, or in moving water and its contents across the surface of the cell

48
Q

Basal Body

A

Structurally very similar to a centriole with microtubule triplets in a “9+0” pattern
- a highly conserved cellular organelle discovered over one hundred years ago

49
Q

Dynein

A

Large motor proteins that are attached along each outer microtubule doublet
- has two “feet” that “walk” along the microtubule of the adjacent doublet, using ATP for energy

50
Q

Microfilaments

A

Thin solid rods that are also called actin filaments because they are built from molecules of actin, a globular protein

51
Q

Cortex

A

Outer cytoplasmic layer of a cell, the semisolid consistency of a gel, in contrast with the more fluid state of the interior cytoplasm

52
Q

Myosin

A

Thousands of actin filaments and thicker filaments are made of this and they interact to cause contractions in muscle cells

53
Q

Pseudopodia

A

The cell crawls along a surface by extending cellular extensions

54
Q

Cytoplasmic Streaming

A

A circular flow of cytoplasm within cells
- especially common in large plant cells, speeds the movement of organelles and the distribution of materials within the cell

55
Q

Intermediate Filaments

A

Larger in diameter of microfilaments, but smaller than that of microtubules
- only found in the cells of some animals, including vertebrates
- specialized for bearing tension (like microfilaments)
- create cell cohesion and prevent the acute fracture of epithelial cell sheets under tension

56
Q

Cell Wall

A

Surrounds the plasma membrane of plant cells and provides tensile strength and protection against mechanical and osmotic stress. It also allows cells to develop turgor pressure, which is the pressure of the cell contents against the cell wall

57
Q

Primary Cell Wall

A

The cellulose-containing layer laid down by cells that are dividing and growing. To allow for cell wall expansion during growth, primary walls are thinner and less rigid than those of cells that have stopped growing

58
Q

Middle Lamella

A

Serves as a cementing layer between the primary walls of adjacent cells

59
Q

Secondary Cell Wall

A

Mainly composed of cellulose, hemicelluloses (xylem and glucomannan) and lignin, and are deposited in some specialized cells, such as tracheary elements, fibers and other sclerenchyma cells

60
Q

Extracellular Matrix (ECM)

A

3D network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and biochemical support to surrounding cells

61
Q

Collagen

A

Most abundant glycoprotein in the ECM of most animal cells, forms strong fibers outside the cells

62
Q

Proteoglycans

A

Where collagen fibers are embedded in a network woven out of proteoglycans secreted by cells
- this molecule consists of a small core protein with many carbohydrate chains covalently attached , so that it may be up to 95% carbohydrate

63
Q

Fibronectin

A

A ubiquitous extracellular matrix (ECM) glycoprotein that plays vital roles during tissue repair

64
Q

Integrins

A

Principal receptors used by animal cells to bind to the extracellular matrix

65
Q

Plasmodesmata

A

Intercellular pores connecting adjacent plant cells allowing membrane and cytoplasmic continuity and are essential routes for intercellular trafficking, communication and signaling in plant development and defense