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Biology 202 > Chapter 6 > Flashcards

Chapter 6 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What are all organisms made out of?

A

Cells

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2
Q

What are cells?

A
  • The basic structural and functional unit of every organism
  • The simplest collection of matter that can be alive
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3
Q

What is cell structure correlated to?

A

Cellular function

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4
Q

How are all cell structures related?

A

All cells are related by their descent from earlier cells

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5
Q

Scientists use what to visualize cells?

A

microscopes

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6
Q

What occurs in a light microscope?

A

-visible light is passed through a specimen and then through glass lenses

-the lenses refract(bend) the light, so that the image is magnified

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7
Q

What are the 3 important parameters of microscopy?

A

magnification, resolution, contrast

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8
Q

Magnification

A

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

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9
Q

Resolution

A

the measure of the clarity of the image or the minimum distance of 2 distinguishable points

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10
Q

Contrast

A

visible differences in parts of the sample

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11
Q

Light microscopes can magnify effectively to about

A

1,000 times the size of the actual specimen

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12
Q

Most sub-cellular structures, including organelles(membrane enclosed compartments) are too small to be resolved by

A

a light microscope

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13
Q

What are the 2 types of electron microscopes(EMs)?

A

Scanning electron microscopes and transmission electron microscopes

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14
Q

Scanning Electron Microscopes (SEMs)

A

focus on a beam of electrons onto the surface of a specimen, providing images that look 3D

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15
Q

Transmission Electron Microscopes (TEMs)

A

-focus on a beam of electrons through a specimen

-used mainly to study the internal structure of cells

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16
Q

What forms of microscopy provide sharper images of 3-dimensional tissues and cells?

A

Confocal microscopy and deconvolution microscopy

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17
Q

What is cell fractionation?

A

-process of taking cells apart and separating the major organelles from one another

-enables scientists to determine the functions of organelles

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18
Q

Centrifuges

A

fractionate cells into their component parts

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19
Q

What are the basic features of all cells(prokaryotes and eukaryotes)?

A

-plasma membrane
-semifluid substance called cytosol
-chromosomes(carry genes in the form of DNA)
-ribosomes(make proteins)
-ATP

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20
Q

Prokaryotic cells are characterized by having

A

-no nucleus
-DNA in an unbound region called the nucleoid
-no membrane-bound organelles
-cytoplasm bound by the plasma membrane

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21
Q

Eukaryotic cells are characterized by having

A

-DNA in a nucleus that is bounded by a membranous nuclear envelope
-membrane-bound organelles
-cytoplasm in the region between the plasma membrane and nucleus
-generally much larger than prokaryotic cells

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22
Q

Mycoplasmas

A

-the smallest bacteria

-1.0 um in diameter

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23
Q

What is the average size in diameter of most bacteria?

A

1-5 um

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24
Q

What is the average size of eukaryotic cells?

A

10-100 um in diame

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25
Q

As the surface area of a cell increases by a factor of n2

A

the volume increases by a factor of n3

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26
Q

Which cells have a greater surface area relative to volume?

A

small cells

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27
Q

What is the plasma membrane?

A

-selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell

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28
Q

What is the general structure of a biological membrane?

A

a double layer of phospholipids

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29
Q

What does the nucleus contain?

A

-most of the DNA in a eukaryotic
-most of the cell’s genes
-usually the most conspicuous organelle

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30
Q

What does the nuclear envelope do?

A

encloses the nucleus, separating it from the cytoplasm

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31
Q

What is the nuclear membrane made up of?

A

a double membrane; each membrane consists of a lipid bilayer

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32
Q

What do ribosomes do?

A

use information from the DNA to make proteins

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33
Q

Pores

A

regulate the entry and exit of molecules from the nucleus

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34
Q

Nuclear lamina

A

-composed of proteins

-maintains the shape of the nucleus

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35
Q

Chromosomes

A

composed of a single DNA molecule associated with proteins(in the nucleus)

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36
Q

Chromatin

A

-DNA and proteins of chromosomes

-condenses to form discrete chromosomes as a cell prepares to divide

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37
Q

What is the nucleolus?

A

-the site of ribosomal RNA (rRNA) synthesis

-located within the nucleus

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38
Q

Ribosomes

A

particles made up of ribosomal RNA and protein

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39
Q

Where do ribosomes carry out protein synthesis?

A

-in the cytosol(free ribosomes)

-on the outside of the endoplasmic reticulum or nuclear envelope(bound ribosomes)

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40
Q

What are the components of the endomembrane system?

A

-nuclear envelope
-endoplasmic reticulum (ER)
-golgi apparatus
-lysosomes
-vacuoles
-plasma membrane

-either continuous or connected via transfer by vesicles

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41
Q

What are the tasks of the endomembrane system?

A

-synthesis of proteins and their transport into membranes and organelles or out of the cell
-metabolism and movement of lipids
-detoxification of poisons

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42
Q

Endoplasmic reticulum (ER)

A

-accounts for more than half of the total membrane in many eukaryotic
-ER membrane is continuous with the nuclear envelope

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43
Q

What are the 2 distinct regions of the ER?

A

smooth ER, rough ER

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44
Q

Smooth ER

A

lacks ribosomes

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45
Q

Rough ER

A

surface is studded with ribosomes

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46
Q

What does the smooth ER do?

A

-synthesizes lipids
-metabolizes carbohydrates
-detoxifies drugs and poisons
-stores calcium ions (in muscles)

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47
Q

What does the rough ER do?

A

-bound ribosomes secrete glycoproteins
-distributes transport vesicles, proteins surrounded by membraned
-is a membrane factory for the cell

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48
Q

what are glycoproteins?

A

proteins covalently bonded to carbohydrates

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49
Q

What does the golgi apparatus consist of?

A

flattened membranous sacs called cisternae

50
Q

What are the functions of the golgi apparatus?

A

-modifies products of the ER
-manufactures certain macromolecules
-sorts and packages materials into transport vesicles

51
Q

cis face

A

“receiving” side of golgi apparatus

52
Q

trans face

A

“shipping” side of golgi apparatus

53
Q

What is a lysosome?

A

a membranous sac of hydrolytic enzymes that can digest macromolecules

54
Q

What can lysosome enzymes do?

A

-can hydrolyze proteins, fats, polysaccharides, and nucleic acids
-work best in the acidic environment inside the lysosome

55
Q

Phagocytosis

A

engulfing of a cell by some cells, forming a food vacuole

56
Q

Lysosomes fuse with

A

the food vacuole and digests the molecules

57
Q

Autophagy

A

use of enzymes to recycle the cell’s own organelles and macromolecules

58
Q

Vacuoles

A

derived from endoplasmic reticulum and goli apparatus; seen in plant or fungal cells

59
Q

Contractile vacuoles

A

-found in many freshwater protists
-pump excess water out of cells

60
Q

Central vacuoles

A

-found in many mature plant cells
-hold organic compounds and water

61
Q

Mitochondria

A

-the sites of cellular respiration( a metabolic process that uses oxygen to generate ATP)

62
Q

What is the site of photosynthesis?

A

chloroplasts (found in plants and algae)

63
Q

What are the similarities between mitochondria, chloroplasts and bacteria?

A

-enveloped by a double membrane
-contain free ribosomes and circular DNA molecules
-grow and reproduce somewhat independently in cells

64
Q

What is the endosymbiont theory?

A

-an early ancestor of eukaryotic cells engulfed a non-photosynthetic prokaryotic cell, which formed an endosymbiont relationship with its host
-the host cell and endosymbiont merged into a single organism, a eukaryotic cell with a mitochondrion
-at least one of these cells may have taken up a photosynthetic prokaryote, becoming the ancestor of cells that contain chloroplasts

65
Q

What is nearly in all eukaryotic cells?

A

mitochondria

66
Q

What types of membranes does a mitochondria have?

A

-a smooth outer membrane
-inner membrane folded into cristae(presenting a large surface area for enzymes that synthesize ATP)

67
Q

What does the inner membrane create?

A

2 compartments:
-intermembrane space
-mitochondrial matrix(some metabolic steps of CR are catalyzed here)

68
Q

What do chloroplasts contain?

A

green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis

69
Q

Chloroplast structure includes

A

-thylakoids
-stroma

70
Q

Thylakoids

A

membranous sacs, stacked to form a granum

71
Q

Stroma

A

internal fluid

72
Q

Chloroplasts is one group of plant organelles called

A

plastids

73
Q

What are peroxisomes?

A

specialized metabolic compartments bounded by a single membrane, oxidative organelles

74
Q

What do peroxisomes produce?

A

hydrogen peroxide (H2O2) and convert it to water

75
Q

What do peroxisomes perform?

A

reactions with many different functions
-convert the fatty acids in seeds to sugars

76
Q

What is the cytoskeleton?

A

-a network of fibers extending throughout the cytoplasm
-organizes the cell’s structures and activities, anchoring many organelles

77
Q

What protein structures is a cytoskeleton composed of?

A

-microtubules
-microfilaments
-intermediate filaments

78
Q

What does the cytoskeleton help with?

A

-support the cell and maintain it’s shape
-interacts with motor proteins to produce motility
-regulate biochemical activities

79
Q

Molecular transport

A

vesicles can travel along “monorails” provided by the cytoskeleton

80
Q

Microtubules

A

-maintain cell shape
-cell motility
-chromosome movements in cell division
-organelle movements
(grow from a centrosome near nucleus)

81
Q

Microfilaments

A

-maintain cell shape
-changes in cell shape
-muscle contraction
-cytoplasmic streaming
-cell motility
-cell division

82
Q

Intermediate filaments

A

-maintain cell chape
-anchorage of nucleus and certain organelles
-formation of nuclear lamina

83
Q

What is a centrosome?

A

“mircotubule-organizing center”
-in animal cells, has a pair of centrioles(each with 9 triplets of microtubules arranged in a ring(9+0))

84
Q

Differences between Cilia and Flagella

A

-beating patterns
-cilia occur in large numbers on cell surface
-flagella are much longer(10-200 um; they share the same diameter)
-usually only 1 or a few flagella per cell

85
Q

What do microtubules control?

A

the beating of cilia and flagella(locomotor appendages of some cells)

86
Q

Common structure between Cilia and Flagella

A

-a core of microtubules sheathed by the plasma membrane
-a basal body that anchors the cilium or flagellum
-a motor protein called dynein, which drives the bending movements of a cilium or flagellum(9+2)

87
Q

How can dynein “walking” move flagella and cilia?

A

-dynein arms alternatively grab, move, and release the outer microtubules
-protein cross-links limit sliding
-forces exerted by dynein arms cause doublets to curve, bending the cilium or flagellum

88
Q

What are microfilaments?

A

solid rods about 7 nm in diameter, built as a twisted double chain of actin subunits

89
Q

What is the structural role of microfilaments?

A

to bear tension, resisting pulling forces within the cell; they form a 3D network called the cortex just inside the plasma membrane to help support the cell’s shape

90
Q

Microvilli

A

core made up of bundles of microfilaments(in intestinal cells)

91
Q

Microfilaments that function in cellular motility contain what protein in addition to actin?

A

myosin

92
Q

Actin filaments are arranged parallel to one another in

A

muscle cells

93
Q

Thicker filaments composed of myosin

A

interdigitate with the thinner actin fibers

94
Q

What drives amoeboid movement?

A

localized contraction brought about by actin and myosin

95
Q

Pseudopodia

A

-cellular extensions
-extend and contract through the reversible assembly and contraction of actin subunits into microfilaments

96
Q

What drives parallel myosin and actin filaments past each other(contraction)?

A

“walking of myosin projections

97
Q

What causes contractions in the cell?

A

interaction of actin filaments with myosin

98
Q

What is a result of actin-myosin interactions and sol-gel transformations in plant cells?

A

cytoplasmic streaming

99
Q

What is cytoplasmic streaming?

A

-a circular flow of cytoplasm within cells
-speeds distribution of materials within the cell

100
Q

Are intermediate filaments larger than microfilaments?

A

yes but they are smaller than microtubules

101
Q

Intermediate filaments support

A

-cell shape
-fix organelles in place
-bearing tension

102
Q

Which is the more permanent cytoskeleton fixture?

A

intermediate filaments

103
Q

Extracellular structures external to the plasma membrane

A

-cell walls of plants
-the extracellular matrix (ECM) of animal cells
-intercellular junctions

104
Q

What does the cell wall in plants do?

A

-distinguishes plant cells from animal cells
-protects plant cell
-maintains its shape
-prevents excessive uptake of water

105
Q

True or False: Prokaryotes, fungi, and some protists also have cell walls

A

True

106
Q

What are plant cell walls made up of?

A

-cellulose fibers
-polysaccharides
-proteins
-may have multiple layers

107
Q

Primary cell wall

A

relatively thin and flexible

108
Q

Middle lamella

A

thin layer between primary walls of adjacent cells

109
Q

Secondary cell wall(in some cells)

A

added between the plasma membrane and the primary cell wall

110
Q

Plasmodesmata

A

channels between adjacent plant cells

111
Q

What are animal cells covered by?

A

extracellular matrix(ECM)

112
Q

What is the ECM made up of?

A

glycoproteins such as collagen, proteoglycans, and fibronectin

113
Q

ECM proteins bind to receptor proteins in the plasma membrane called

A

integrins

114
Q

Functions of ECM

A

-support
-adhesion
-movement
-regulation

115
Q

Intercellular junctions

A

facilitate physical contact between neighboring cells in tissues, organs, or organ systems

116
Q

What are the types of intercellular junctions?

A

-Plasmodesmata
-Tight junctions
-Desmosomes
-Gap junctions

117
Q

What are plasmodesmata? And what do they allow?

A

-channels that perforate plant cell walls
-allow water, small solutes and sometimes proteins and RNA pass from cell to cell

118
Q

At tight junctions

A

membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid(interlocking of proteins binds lipid portion of membrane)

119
Q

What do desmosomes do?(anchoring junctions)

A

fasten cells together into strong sheets

120
Q

What do gap junctions provide?(communicating junctions)

A

cytoplasmic channels between adjacent cells(connexons form protein channels, allows molecules to pass for (rapid)communication; allow ions to pass; coordinated contractions in heart muscle)

121
Q

What is attached to the cytoskeleton to resist stretching and twisting?

A

cell adhesion molecules + intercellular cement(on dense areas)

122
Q

Macrophage’s ability to destroy bacteria involves

A

the whole cell, coordinating components such as the cytoskeleton, lysosomes, and plasma membrane

Biology 202 (5 decks)

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