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Bio 201A > Quiz 2 The Cell and Membrane. > Flashcards

Quiz 2 The Cell and Membrane. Flashcards

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1
Q

Under what domains do prokaryotes fall?

A

Under Domains Bacteria and Archaea

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2
Q

Characteristics of prokaryotes

A
  1. small in size
  2. no nucleus just nucleoid region
  3. most have no membrane bound organelles
  4. DNA in nucleiod region, ribosomes (dif from eukaryotic ribosomes), and plasma membrane
  5. may also have a cell wall, capsule, fimbriae, and flagella (tail)
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3
Q

What domain and kingdoms can eukaryotes fall under?

A

Domain Eukarya, Kingdoms Fungi, Plantae, Animalia, and Artificial Protists

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4
Q

Characteristics of eukaryotes

A
  1. larger in size than prokaryotes
  2. surrounded by a plasma membrane and have ribosomes
  3. have nucleus and other membrane bound organelles
  4. May have cell walls (Plantae, Fungi, and many Protists)
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5
Q

protoplasm

A

living part of the cell

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6
Q

cytoplasm

A

area between nucleus and plasma membrane, or interior of prokaryotic cell

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7
Q

cytosol

A

semi-fluid matrix of cytoplasm

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8
Q

organelles

A

subcellular structures with specific functions, most are surrounded by a membrane (except ribosomes)

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9
Q

why are ribosomes not actually considered organelles?

A

lack a membrane, but still function as organelles

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10
Q

ribosomes

A

composed of rRNA and proteins

has two subunits (large and small)

two types: free ribosomes in cytoplasm and ribosomes attached to rough ER

in both prokaryotes and eukaryotes

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11
Q

what is a difference between proteins made by ribosomes free in the cytoplasm and ribosomes attached to rough ER

A

proteins made from the free ribosomes are soluble in cytoplasm and proteins made in attached ribosomes are needed for other organelles

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12
Q

main function of ribosomes

A

protein synthesis

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13
Q

what type of ribosomes do prokaryotes only have?

A

free, because don’t have an ER

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14
Q

main functions of nucleus

A
  1. directs metabolism, growth, development, and reproduction by directing protein synthesis
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15
Q

characteristics of nucleus

A

nuclear envelope is made of two lipid bilayers

nuclear pores are very selective

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16
Q

nuclear lamina

A

netlike array of protein filaments that mechanically supports the nuclear envelope, nuclear matrix of proteins also present throughout the nuclear interior

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17
Q

chromatin

A

DNA associated with proteins, dark stained hazy area in non-dividing cells, in dividing cells chromatin condenses into chromosomes

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18
Q

nucleolus

A

site of synthesis of ribosomal subunits, may be two or more per cell, dark oval stained area in non-dividing cells, rRNA synthesized

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19
Q

nucleolar organizing center

A

contains multiple copies of genes needed to make rRNA

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20
Q

vesicles

A

short lived sacs enclosed by a membrane, often used to transport molecules that are pinched off of golgi apparatus or ER

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21
Q

Rough Endoplasmic Reticulum

A

composed of cisternae

ribosomes are attached to the outer cisternae membrane

can be continuous with nuclear envelope

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22
Q

cisternae

A

parallel fluid filled sacs surrounded by membrane

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23
Q

main functions of the Rough ER

A
  1. protein synthesis
  2. protein packaging
  3. protein secretion
  4. phospholipid synthesis (makes membranes)
  5. glycoprotein synthesis (often secretory proteins)
  6. synthesize transport vesicles (pinched off)
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24
Q

Smooth ER

A

composed of cisternae

no ribosomes attached to membrane

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25
Q

Functions of smooth ER

A
  1. carbohydrate metabolism
  2. detoxification of drugs and poison
  3. calcium ion storage
  4. produces oils, phospholipids, and steroids including steroid hormones
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26
Q

Golgi apparatus

A

composed of cisternae

different rxns occur inside or on outside in membrane enclosed sacs

receives ER transport vesicles with molecules enclosed, membranes fuse and the molecules enter cis side and exit trans side of Golgi in vesicles

vesicles can carry molecules backwards to other side of Golgi or to ER

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27
Q

Functions of Golgi Apparatus

A
  1. directs macromolecule transport
  2. sorts, modifies, and re-labels molecules for transport
  3. synthesizes carbohydrates including polysaccharides
  4. modifies carbohydrate tags on molecules
  5. modifies glycoproteins
  6. modifies phospholipids
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28
Q

lysosomes

A

“recycling center”

membrane bounded sacs containing powerful digestive enzymes

they are first made in rough ER or Golgi, pinched off of the Golgi apparatus

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29
Q

Main functions of lysosomes

A
  1. involved in exocytosis
  2. digests old macromolecules (recycled and reused)
  3. digests old organelles
  4. programmed cell death (apoptosis)
  5. contain lipases (enzymes that breakdown lipids)
  6. contain carbohydrases
  7. contain proteases
  8. contain nucleases
  9. food digestion in protists
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30
Q

vacuoles

A

membrane enclosed sacs

usually larger and live longer than vesicles

present in plant cells, not as prevalent in animal cells

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31
Q

food vacuoles

A

store and break apart food in some protists

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32
Q

contractile vacuoles

A

expel excess water in some protists

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33
Q

central vacuole in plants

A

enclosed by tonoplast (membrane), helps maintain turgidity (water pressure) of cells, stores organic compounds and inorganic ions, break down organic molecules, store pigments, dumping ground for toxic waste

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34
Q

endomembrane system

A

“work together”

INCLUDES: nuclear envelope, rough ER, smooth ER, Golgi apparatus, lysosomes (if present), vacuoles (if present), and plasma membrane

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35
Q

peroxisomes

A

membrane enclosed sacs

sometimes crystalline lattice appearance

contain many enzymes

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36
Q

Main functions of Peroxisomes

A
  1. involved in oxidation reaction that strip hydrogen atoms from organic molecules to make double bonds and produce H2O2 (oxidases)
  2. contain catalase to break down hydrogen peroxide
  3. in some peroxisomes, fatty acids are broken down into smaller molecules
  4. detoxify alcohols
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37
Q

Main function of mitochondria

A
  1. Site of aerobic respiration
  2. food is broken down to make ATP
  3. synthesize some proteins but most are transported from cytosol into mitochondrion are moved around in cell using cytoskeleton
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38
Q

mitochondria

A

surrounded by membrane with inner membrane system

contain their own DNA

contain free ribosomes (space inside)

divide independently of cell

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39
Q

outer membrane of mitochondria

A

smooth and permeable to many small ions

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40
Q

inner membrane of mitochondria

A

convoluted, more selective, many enzymes of cellular respiration are embedded in membrane, convolution increases surface area (cristae = folds)

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41
Q

intermembrane space on mitochondria

A

area between two membranes

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42
Q

matrix of mitochondria

A

inner compartment, contains enzymes involved in cellular respiration

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43
Q

plastids

A

organelles in plants only

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44
Q

amyloplasts

A

store starch

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45
Q

chromoplasts

A

plastids with colored pigments other than chlorophyll

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46
Q

chloroplasts

A

plastids that contain chlorophyll (green pigment that absorbs light energy during photosynthesis)

contain their own DNA and ribosomes

divide independently of cell (similar to binary fission not mitosis)

double membrane surrounds internal membrane system

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47
Q

main functions of chloroplasts

A
  1. photosynthesis
  2. synthesize carbohydrates
  3. synthesize amino acids
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48
Q

thylakoids

A

internal membrane enclosed sacs, where light dependent rxns occur in chloroplasts

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49
Q

grana

A

term for stacks of thylakoids in chloroplasts

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50
Q

stroma

A

semi-fluid region outside of thylakoids where light independent rxns occur (ex. Calvin’s cycle)

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51
Q

endosymbiosis or endosymbiont theory

A

theory that mitochondria and chloroplasts are ancient prokaryotes that took up residence in the precursors of eukaryotic cells, survived, and started to divide independently of eukaryotic cell precursor

some of their genes have been thought to have moved into the nucleus of their host cell

52
Q

evidence of endosymbiosis

A
  1. many symbiotic relationships between prokaryotes and eukaryotes are known to exist
  2. mitochondria and chloroplasts are similar to bacteria in size and shape
  3. both have their own single circular DNA not associated with histones
  4. mitochondria and chloroplasts both have ribosomes that are like prokaryotic ribosomes
  5. mitochondria and chloroplasts both divide independently of host cell and they divide like prokaryotes (binary fission)
  6. inner membranes of both have enzymes and transport systems that are homologous to these found in living prokaryotes
53
Q

cytoskeleton

A

network of fibers throughout the cytoplasm that functions in support, movement, and regulation, dynamic

can transmit forces from the surface to the interior of the cell

54
Q

what are the 3 types of filaments associated with the cytoskeleton

A

microtubules, microfilaments, and intermediate filaments

they all function as cell support and cell structure

55
Q

dynein motor proteins

A

responsible for bending movements of cilia and flagella, shape changes using energy of ATP, one foot maintains contact while other foot releases and attaches one step further “like walking”

microtubule doublets held in place by cross linking proteins

56
Q

microtubules

A

hollow fibers made of protein tubulin dimers

grow out of a centrosome (microtubule organizing center) in animal cells

57
Q

Main functions of microtubules

A
  1. cell support (compression resisting)
  2. cell movement (part of cilia and flagella structure)
  3. involved in cell division (moves chromosomes around as spindle apparatus)
  4. organelle movement
  5. vesicle movement
58
Q

centrioles

A

small cylindrical structures in pairs oriented at right angles in centrosomes

contain 9 triplets of microtubules

replicate before cell division

may help organize spindle apparatus that moves chromosomes during cell division

plant cells lack centrosomes with centrioles

59
Q

cilia and flagella

A

hair like structures that move cell or move things past cell

surrounded by a membrane

anchored by basal body

flagella (few and long)

cilia (many and short)

60
Q

primary cilium

A

nonmotile signal receiving cilium in many vertebrate animal cells,

membrane proteins transmit chemical and mechanical signals from the environment to the cell interior triggering pathways that may lead to changes in cell activity

61
Q

microfilaments (actin filaments)

A

solid fibers made of protein actin

often interacts with myosin

62
Q

main functions of microfilaments

A
  1. cell support (bear tension)
  2. cell division (cytokinesis or division of cytoplasm)
  3. cell movement (creeping movement)
  4. enable contents of cell to move around in order to distribute things (cytoplasmic streaming)
  5. organism movement (muscle contraction)(work with myosin protein)
63
Q

cortical microfilaments

A

supportive microfilaments just inside of the plasma membrane that helps give cells shape

make up microvilli that increase surface area of membranes

64
Q

intermediate mircofilaments

A

structure is highly variable

some are made of repeating keratin subunits

only in some animals including vertebrates

65
Q

main functions of intermediate microfilaments

A
  1. cell support (bear tension)
  2. cell adhesion (desmosomes)
  3. hold organelles such as nucleus in place
  4. formation of nuclear lamina that supports nuclear envelope
66
Q

cell wall

A

supportive layer outside cell membrane

can find in plants., fungi, most bacteria, and many protists

67
Q

main functions of cell wall

A
  1. cell and organism structural support
  2. prevents excessive uptake of water
  3. may decrease water loss
  4. protection of cell and organism
68
Q

cell wall in plants

A

mostly cellulose and other carbohydrates that support cells and organism

helps to retain water in plant

69
Q

primary cell wall

A

thin, can stretch, laid down first (outer)

70
Q

secondary cell wall

A

in between primary and membrane

makes wall rigid

cannot stretch

71
Q

middle lamella

A

cements adjacent cells together

mostly made of pectins (carbohydrates)

72
Q

cell walls in fungi

A

cell walls are mostly chitin

73
Q

cell wall in bacteria

A

mostly peptidoglycans (polymers of modified sugars cross linked by short polypeptides)

walls of archaea lack peptidoglycans

74
Q

cell wall in protists

A

highly variable

75
Q

extracellular matrix

A

outside of the membrane of animals

include glycoproteins (main), collagen, proteoglycans, fibronectins

76
Q

glycoproteins in extracellular matrix

A

main component along w other carbohydrate containing molecules

77
Q

collagen

A

glycoprotein fibers, abundant

part of extracellular matrix

78
Q

proteoglycans

A

form a web in extracellular matrix

79
Q

fibronectins

A

bind to integrins (integral proteins) that are built into the membrane

integrins bind to microfilaments in the cytoskeleton

80
Q

main function of extracellular matrix

A
  1. tissue support**
  2. provides tracks for cell movement
  3. cell signaling
81
Q

intercellular junctions in plants

A

plasmodesmata (areas in cell wall where cytoplasm of one cell is directly continuous with another)

functions in cell to cell communication

82
Q

plasmodesmata in plants

A

intercellular junction in plants in which is the areas in the cell wall where cytoplasm of one cell is directly continuous with another

lined with plasma membrane with a central desmotubule of ER

83
Q

what are the types of intercellular junctions in animals?

A

tight junctions and gap junctions and desmosomes

84
Q

tight junctions in animals

A

intercellular junction in which membranes of neighboring cells are fused with help of proteins

holds cell together tightly and forms a seal

FUNCTION IS: cell adhesion

85
Q

gap junctions in animals

A

intercellular junction in which protein channels lined between cells

FUNCTION: in cell to cell communication

86
Q

desmosomes in animals

A

intercellular junction in which a plate using intermediate filaments holds cells together

FUNCTION IS: cell adhesion

87
Q

selective permeability

A

membranes allow some things to cross but not others

amphipathic (one side is charged the other isnt)

molecules that are hydrophobic pass easily

polar molecules and ions do not easily cross the membrane

transport proteins move things across that can’t on their own (ions and polar molecules)

88
Q

active transport

A

requires energy

move things against concentration gradient (low to high)

ex: membrane pumps - carrier proteins

proteins use energy to move molecules or ions against their gradients

89
Q

passive transport

A

does not require energy

can only move things along concentration gradient (high to low concentration)

90
Q

types of passive transport?

A

diffusion and facilitated diffusion

91
Q

diffusion

A

movement of molecules so they spread out evenly int available space

net movement of a substance from high to low concentration until equillibrium

increases randomness of molecules

due to kinetic energy of molecules

spontaneous because it decreases free energy and increases entropy

92
Q

facilitated diffusion

A

passive transport of molecules or ions aided by proteins

two types: channel proteins, and carrier proteins

93
Q

osmotic concentration

A

total solute concentration of a solute

94
Q

concentration gradient

A

graded change in the concentration of a substance over some distance

95
Q

the higher the osmotic (particles) concentration…..? in a solution

A

the lower the water concentration in a solution

96
Q

osmosis

A

diffusion of water across a selectively permeable membrane

free water concentration difference is important

97
Q

isotonic

A

solution has same osmotic concentration as cell (or another solution)

98
Q

hypertonic

A

solution has greater osmotic concentration than the cell ( or another solution)

99
Q

hypotonic

A

solution has lower osmotic concentration than cell (or another solution)

100
Q

Animal cells in an isotonic solution?

A

no net movement of water, normal situation

101
Q

Animal cells in a hypertonic solution?

A

water diffuses from cell to solution and cell may shrivel or crenulate

102
Q

Animal cells in a hypotonic solution?

A

water diffuses from solution to cell and the cell can lyse or explode

103
Q

Plant cells in an isotonic solution?

A

no net movement of water

104
Q

Plant cells in a hypertonic solution?

A

water diffuses out of cell, plasmolysis (membrane pulls away from cell wall, cell contents shrink)

105
Q

Plant cells in a hypotonic solution?

A

water diffuses into cell and so water pressure inside of cell increases (turgor pressure) , normal situation

106
Q

Membrane structure

A

lipid boundary that surrounds cell

fluid and selectively permeable

phospholipids and many proteins are amphipathic molecules (hydrophobic one one side and hydrophilic on the other)

membranes have distinct inside and outside faces

phospholipids held together by weak hydrophobic interactions

cholesterol often present in animal cell membranes

107
Q

Fluid Mosaic Model (Characteristics of Membrane)

A

membrane comprised of phospholipid bilayer

fluid mosaic (mixture) of lipids, proteins, and carbohydrates

selectively permeable

fluidity- membrane flows, phospholipids drift laterally, some proteins move

108
Q

fluidity of membrane

A

fluidity is decreased when fatty acid tails are saturated

stays fluid at lower temperatures if many unsaturated hydrocarbon tails are present

fluidity decreased when too much cholesterol present

109
Q

transport proteins functions in membranes

A

active transport through carrier proteins (pumps)

passive transport through channel proteins and carrier proteins

110
Q

enzymatic activity functions in membranes

A

some enzymes catalyze reactions on membrane

111
Q

signal transduction functions in membranes

A

process in which a cell signal is converted to a cellular response

112
Q

cell to cell recognition function in membranes

A

oligosaccharides (carb) serve as name tags

allows cells to recognize like cells

allows cells to develop properly and organize into tissues

provides immunity

113
Q

intercellular joining

A

EX: intermediate filaments in desmosomes

114
Q

cell structure function in membranes

A

attachment of proteins to cytoskeleton and extracellular matrix

115
Q

membrane pumps

A

carrier proteins that move molecules or ions against their gradient often using ATP

116
Q

membrane potential

A

all cells have voltage across their plasma membrane

voltage is electrical potential energy

due to separation of opposite charges

usually -70 millivolts

more negative inside the cell

unequal distribution of ions across a membrane

unequal distribution of charges

117
Q

electrogenic pumps

A

membrane pumps that generate a voltage by redistributing ions

ex: NA+/K+ pump and H+ pump (actively transports H+ ions out of cell)

118
Q

electrochemical gradient

A

osmotic gradient plus gradient charge

helps govern diffusion

substances ALWAYS diffuse along electrochemical gradient (lot of potential energy)

substances USUALLY diffuse along osmotic gradient (when there is a electrochemical gradient and/or difference in charge)

119
Q

cotransport

A

substance that has been pumped across membrane can carry another substance with it as it diffuses back

ex: sucrose-H+ cotransporter

120
Q

What two types of bulk transport are there?

A

exocytosis and endocytosis

121
Q

exocytosis

A

movement of large molecules to outside of cell

membrane enclose vesicle fuses with cell membrane and moves molecules to outside of cell

122
Q

endocytosis

A

movement of large molecules to the inside of the cell

membrane forms a vesicle around molecules and pulls them inside the cell

123
Q

three types of endocytosis

A

phagocytosis

pinocytosis

receptor-mediated endocytosis

124
Q

phagocytosis

A

movement of particles into cell

ex: cell engulfs bacterium

125
Q

pinocytosis

A

movement of fluid into cell

nonspecific

126
Q

receptor-mediated endocytosis

A

movement of specific molecules into the cell that first binds to receptors

ex: cells use to take in cholesterol

Bio 201A (2 decks)

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