BIOL235_Chap3 Flashcards
1
Q
cells
A
are the basic, living, structural, and functional units of the body
2
Q
plasma membrane
A
forms the cell’s flexible outer surface, seperating the cell’s internal environment from its external environment
3
Q
cytoplasm
A
consists of all cellular contents betw plasma membrane and nucleus
cytosol + organelles
4
Q
cytosol
A
fluid portion of the cytoplasm = intracellular fluid
5
Q
nucleus
A
large organelle that houses most of cell’s dna
6
Q
3 main parts of a cell
A
plasma membrane
cytoplasm
nucleus
7
Q
what does the plasma membrane do?
A
it provides a flexible yet sturdy barrier that sourrouands and contains the cytoplasm of a cell
8
Q
fluid mosaic model
A
model of a cell that says the molecular arrangement of the plasma membrane resembes a continually moving sea of fluid lipids that contains a mosaic fo many diff proteins
9
Q
lipid bilayer
A
the basic structural framework of the plasma membrane
2 back-to-back layers made up of 3 lipid molecules (phospholipids, cholesterol, glycolipids)
10
Q
3 lipid molecules making up the lipid bilayer
A
phospholipids
cholesterol
glycolipids
11
Q
phospholipids
A
lipids that contain phosphorus
12
Q
cholesterol
A
carbohydrate important for cell shape
inside plasma membrane
steroid with an attached OH group
13
Q
glycolipids
A
lipids with attached carbohydrate groups
14
Q
integral proteins
A
proteins that extend into or thru the lipid bilayer and are firmly embedded in it
most are transmembrane proteins
most are also glycoproteins
15
Q
transmembrane proteins
A
proteins that span the entire lipid bilayer and protrude into both the cytosol and extracellular fluid
16
Q
peripheral proteins
A
proteins that are not firmly embedded in the membrane. they are attached to the polar heads of membrane lipids or to integral proteins at the inner or outer surface of the membrane
17
Q
glycoproteins
A
proteins with carbohydrate groups attached to the ends that protrude into the extracellular fluid
18
Q
glycocalyx
A
an extensive sugary coat formed by carbohydrate portions of glycolipids and glycoproteins
19
Q
6 membrane’s functions
A
- ion channels (integral)
- carrier (integral)
- receptor (integral)
- enzyme (integral + peripheral)
- linker (integral + peripheral)
6 cell identity marker (glycoprotein)
20
Q
ion channels
A
pores or holes that specific ions can flow thru to get into or out of the cell
most are selective
formed by integral proteins
21
Q
carriers
A
integral proteins that act as transporters and selectively move a polar substance or ion from one side of membrane to other
integral proteins
22
Q
receptors
A
integral proteins that serve as cellular recognition sites where each type of recepor recognizes + binds a specific molec
integral
23
Q
enzymes
A
integral or peripheral proteins that catalyze specific chemical reactions at the inside or outside surface of the cell
integral or peripheral
24
Q
linkers
A
integral or peripheral proteins that anchor proteins in the plasma membranes of neighboring cells to one another or to protein filaments inside + outside the cell
integral or peripheral
25
cell-identity markers
membrane glycoproteins and glycolipids that enable a cell to recognize other cells of the same kind during tissue formation or recognize + respond to potentially dangerous foreign cells
glycoproteins
26
membranes are
fluid structures
27
selective permeability
a property of plasma membranes that permits some substances to pass thru it more readily than others
28
concentration gradient
a difference in concentration of a chemical from one place to antoher
29
electrical gradient
difference in electrical charges betw two regions
membrane potential
30
membrane potential
a name for electrical gradient bec it occurs across plasma membrane
31
electrochemical gradient
the combined influence of the concentration gradient + electrical gradient on movement of a particular ion
32
passive processes
process where a substance moves down its concentration or electrical gradient to cross membrane using its own kinetic energy
33
active process
process where cellular energy is used to drive the substance "uphill" against its concentration or electrical gradient
34
vesicles
tiny spherical membrane sacs that can help substances enter or leave cells through active process
35
diffusion
a passive process in whihc random mixing of particles in a solution occurs because of the particles' kinetic enrgy
both solutes + solvent and liquid undergo diffusion
36
5 factors influencing diffusion rate
1. steepness of the concentration gradient
2. temperature
3. mass of diffusing substance
4. surface area
5. diffusion distance
37
steepness of concentration gradient influence on diffusion rate
the greater the difference in concentration betw 2 sides of membrane, the higher the rate of diffusion
38
temperature influence on diffusion rate
the higher the temp, the faster the rate of diffusion
39
mass of the diffusing substance influence on diffusion rate
the larger the mass of the diffusing particle, the slower its diffusion rate
40
surface area influence on diffusion rate
the greater the distance over which diffusion must occur, the longer it takes
41
simple diffusion
a passive process where substances move freely thru the lipid bilayer of the plasma membranes of cells without the help of membrane transport proteins
42
facilitated diffusion
process where an integral membrane protein assists a specific substance across the membrane (channel or carrier)
43
channel-mediated facilitated diffusion
a solute moves down its concentration gradient across the lipid bilayer thru a membrane channel
mostly ion channels
44
gated channel
when part of the channel protein acts as a plug or gate, changing shape in one way to open the pore and in another way to close it
45
carrier-mediated facilitated diffusion
where a carrier moves a solute down its concentration gradient across the plasma membrane
passive process
46
transport maximum
number of carriers available in a plasma membrane resulting in an upper limit for how much solute can be transported in carrier-mediated facilitated diffusion
47
osmosis
type of diffusion where there is a net movement of solvent thru a selectively permeable membrane
water moves from lower so solute conc to higher
48
aquaporins
integral membrane proteins that function as water channels
play critical role in controlling water content of cells
49
hydrostatic pressure
pressure exerted by a liquid on the membrane that results when osmosis of water occurs such that 1 side has more water than the other
50
osmotic pressure
pressure that is proportional to the concentration of solute particles that cannot cross the membrane
the higher the solute conc, the higher the solutions osmotic pressure
51
tonicity
measure of the solutions ability to change the volume of cells by altering their water content
52
isotonic solution
any solution in which a cell maintains its normal shape and volume
53
hypotonic solution
a solution that has a lower conc of solutes that the cytosol inside the red blood cells
54
hemolysis
rupture of red blood cells due to water molecs entering cells faster than leaving and leading to RBC swell and burst in hypotonic solutiosn
55
hypertonic solution
solution that has a higher conc of solutes than cytosol inside RBC
leads to crenation
56
crenation
shrinkage of cells due to hypertonic solution, where water leaves cells faster than it enters
57
active transport
an active process because energy is required for carrier proteins to move solutes across membrane agains a conc gradient.
58
primary active transport
active transport where energy derived from hydrolysis of ATP changes the shape of a carrier protein which pumps a substance across a plasma membrane against its concentration gradient.
59
pumps
carrier proteins that mediate primary active transport
60
sodium-potassium pump
carrier protein that is most prevalent primary active transport mechanism and expels sodium ions from cells and brings potassium ions in
61
Na+-K+ ATPase
sodium-potassium pump
62
secondary active transport
active transport where the energy stored in a Na+ or H+ concentration gradient is used to drive other substances across the membrane against their own conc gradients
63
process of secondary active transport
a carrier protein simultaneously binds to Na+ and another substances and then changes its shape so that both substances cross the membrane at the same time
64
symporters
transporters that move 2 substances in the same direction
65
antiporters
transporters that move 2 substances in opposite directiosn across the membrane
66
vesicle
intracellular cell movement
small spherical sac
transports a variety of substances from one structure to anther within cells
also import/release materials into intracellular fluid
67
endocytosis
vesicle transport where materials move into a cell in a vesicle formed from the plasma membrane
68
exocytosis
vesicle transport where materials move out of a cell by the fusion with he plasma membrane of vesicles formed inside the cell
69
edocytosis + exocytosis both require...
energy supplied by ATP
70
6 steps of receptor-mediated endocytosis
1. binding
2. vesicle formation
3. uncoating
4. fusion with endosome
5. recycling of receptors to plasma membrane
6. degradation in lysosomes
71
phagocytosis = cell eating
a form of endocytosis where cell engulfs large solid particles (like wornout cells, bacteria, or viruses)
72
phagocytes
body cells that can carry out phagocytosis
73
pinocytosis = cell drinking
bulk-phase endocytosis most body cells carry out
form of endocytosis where tiny droplets of extracellular fluid are taken up
74
bulk-phase endocytosis
where the plasma membrane folds inward and forms a vesicle containing a droplet of extracellular fluid
75
3 types of endocytosis
1. receptor mediated
2. phagocytosis
3. bulk-phase
76
exocytosis
releases materials from a cell
all cells carry it out
77
transcytosis
active process where vesicles undergo endocytosis on one side of a cell, move across the cell, and undergo exocytosis on the opposite side
in and out
78
cytoplasm
cellular contents betw plasma membrane and nucleus
cytosol + organelles
79
cytosol
intracellular fluid
55% of cell volume
site of many chem reactions for cell's existance
80
cytoskeleton
network of protein filaments that extends throughout the cytosol
81
microfilaments
thinnest elements of cytoskeleton
82
microvilli
cell extensions that inc the surface area of the cell, little fingerlike projectsion of the plasma membrane
83
intermediate filaments
thicker than microfilaments, thinner than microtubules
help stabilize organell position and attach cells tog.
84
microtubules
largest cytoskeleton components
long unbranched hollow tubes
help determine cell shape
85
organelles
specialized structures within the cell that have characteristic shapes, perform specific functions
86
centrosome
microtubule organizing center
(centrioles + pericentriolar matrix)
87
centriols
cylindrical structures made up of 9 clusters of 3 microtubules arrange in circular pattern
88
pericentriolar matrix
organizing centers for growth of mitotic spindle, surrounds centrioles and contains hundreds of ring-shaped complexes composed of tubulin protein
89
during cell division, centrosomes...
replicate so that succeeding generations of cells have the capacity for cell division
90
cilia
motile projection of the cell surface that is numerous short, hair-like projectiosn that extend from the surface of the cell
91
flagella
motile projections of the cell surface that are longer than cilia. usually move entire cell
rapid wiggling in wave-like pattern
sperm cell's tail
92
ribosomes
the sites of protein synthesis
lots of RNA
located within mitochondria + synthesize mitochondrial proteins
93
endoplasmic reticulum = ER
network of membranes in the form of flattened sacs or tubules that extends from nuclear envelop and projects throughout the cytoplasm
extensive
94
Rough ER
ER that is continuous with the nuclear membrane and folded into series of flattened sacs
outer surface studded with ribosomes as sites for protein synthesis
produces secretory proteins, membrane proteins, + other organellar proteins
95
ER
endoplasmic reticulum
96
Smooth ER
extends from rough ER to form network of membrane tubules
does not have ribosomes
has unique enzymes that make it functionally more divers than rough ER
synthesizes fatty acids, steroids,
97
Golgi complex
first step of transport pathway that
consists of 3-20 flattened membranous sacs called cisternae; strucutrally + functionally divided into entry (face, medial ceisternae, and exit face)
98
cisterns
small, flattened membranous sacs with bulging edges
often curved, give curved shape to golgi
99
medial cisterns
sacs betw entry + exit faces
100
transfer vesicles
bud from the edges of cisterns and move specific enzymes back toward netry face and some partially modified proteins toward exit face
101
secretory vesicles
store some processed proteins and deliver them to the plasma membrane
102
membrane vesicles
deliver contents of some processed proteins to the plasma membrane for incorporation into membrane
enables golgi to add new segments to PM as old segments are lost
103
lysosomes
membrane-enclosed vesicles that form from golgi complex
contain powerful digestive and hydrolytic enzymes that can break down lots of molecs
104
autophagy
process by which entire worn-out organells are digested
105
autolysis
process by which lysosomal enzymes may destroy the entire cell that contains them
pathological conditions
responsible for tissue deterioration after death
106
peroxisomes = microbodies
groups of organelles that contains several oxidases (enzymes that than can oxidize various ogranic substances.)
107
proteasomes
tiny barrel-shaped structure that contains proteases - protein emzymes
central core that helps with conti. destruction of unneeded, damaged or faulty proteins
108
mitochondria
powerhouses of the cell
generate most of ATP in aerobic respiration
109
a mitochondrion consists of
an external mitochondrial membrane + an internal mitochondrial membrane
110
mitochondrial cristae
series of folds contained in internal mitochondrial membrane
111
mitochondrial matrix
central fluid-filled cavity of a mitochondrion enclosed by internal mitochondrial membrane
112
apoptosis
the orderly, genetically programmed death of a cell
113
nucleus
spherical/oval-shaped structure that is prominent feature of cell
red blood cells have none
114
nuclear envelope
double membrane (both lipid bilayers) that separates nucleus from cytoplasm
115
nuclear pores
openings that extend thru the nuclear envelope
116
nuceloli
spherical bodes inside nucleus
produce ribosomes
(basically a cluster of protein, DNA + RNA)
117
genes
hereditary units of the cell which control cellular strucutre and direct activiites
118
chromatin
what DNA is made of
complex of DNA (and sometimes RNA) that a long molec of DNA coiled tog with several proteins
119
genome
total genetic information carried in a cell/organism
120
nucleosome
each bead in the bead-on-a-strong strucutre of chromatin that consists of a double-stranded DNA wrapped twice around 8 core proteins/histones
121
histones
core of 8 proteins which DNA are wrapped arnd in a nucleosome
122
chromatin fiber
for cells that are not dividing, nucelosomes coil arnd it
123
chromatids
constitutes a chromosome in during cell division
124
proteome
all of an organism's proteins
125
gene expression
process where a gene's DNA is used as a template for synthesis of a specific protein
126
base triplet
sequence of 3 nucelotides in DNA where genetic info is stored
127
codon
complementary sequence of 3 nucleotides which each DNA base triplet is transcribed as
128
genetic code
set of rules that relate to the base triplet sequence of DNA to the corresponding codons of RNA and amino acids they specify
129
transcription
where genetic info represented by the sequence of base triplets in DNA serves as template for copying info into a complemtnary sequence of codons
130
3 types of RNA made from DNA template
1. messenger RNA (mRNA)
2. Ribosomal RNA (rRNA)
3. Transfer RNA (tRNA)
131
mRNA
messenger RNA
directs synthesis of a protein
132
rRNA
ribosomal RNA
joins with ribosomal proteins to make ribosomes
133
tRNA
transfer RNA
binds to an amino acid and holds in place un a ribosome until it is incorporated into a protein during translation
134
anticodon
a triplet of nucelotides on the end of a tRNA that opposite to the end that carries a specific amino acid
135
RNA polymerase
enzyme that catalyzes transcription of DNA
136
promoter
segment of DNA where transcription begins and a special nucleotide sequence located near beginning of a gene
137
terminator
nucleotide sequence where transcription of of the DNA strand ends
138
introns
regiosn within a gene that do not code for parts of proteins
located betw exons
139
exons
regions of within a gene that do code for for segments of protein
140
translation
process where the nucleotide sequence in a mRNA molec specifies the amino acid sequence of a protein
carried out by ribosomes in the cytoplasm
141
cell division
process by which cells reproduce themselves
142
polyribosome
several ribosomes attached to the same mRNA
143
somatic cell
any cell of the body other than a germ cell
144
germ cell
a gamete (sperm or oocyte) or any precursor cell destined to become a gamete
145
in somatic cell division...
cell undergoes mitosis and cytokinesis to produce 2 genetically identical cells, each with same # + kind of chromosomes as original
(mitosis = nuclear division)
(cytokinesis = cytoplasmic division)
146
mitosis
nuclear division
147
cytokinesis
cytoplasmic division
148
reproductive cell division
mechanism that produces gametes
meiosis, where # of chromosomes is dec by half
149
cell cycle
orderly sequence of events in which a somatic cell duplicates its contents and divides in 2
150
homologous chromosomes
2 chromosomes that make up each pair
contain similar genes arranged in same order
151
sex chromosomes
designated X and Y
152
diploid (2n) cells
what somatic cells are called bec they contain 2 sets of chromosomes
153
interphase
where the cell replicates its DNA
cell does most of its growing
154
mitotic (M) phase
phase in the cell cycle which results in the formation of 2 identical cells, consists of nucelar divison (mitosis) and cytoplasmic division (cytokinesis) to form 2 identical cells
155
mitosis
distribution of 2 sets of chromosomes into 2 seperate nuclei
exact partitioning of genetic information
156
4 stages of mitosis
1. prophase
2. metaphase
3. anaphase
4. telophase
157
prophase of mitosis
chromatin fibers condense into paired chromatids
nucleolus and nuclear envelope disappear
each centrosome moves to an opposite pole of the cell
158
centromere
constricted region that holds the chromatid pair tog
159
mitotic spindle
a football-shaped assembly of microtubules that attach to the kinetochore.
160
metaphase of mitosis
centromeres of chromatid pairs line up at metaphase plate.
161
Anaphase of mitosis
centromeres split
identical sets of chromosomes move to opposite poles of cell
162
telophase of mitosis
nucelar envelopes and nucleoli reappear
chromosomes resume chromatin form
mitotic spindle disappears
163
cytokinesis of mitosis
cytoplasm division
contractile ring forms cleavage furrow arnd center of cell, dividing cytoplasm into separate and equal portions
164
cytokinesis
division of a cell's cytoplasm + organelles into 2 identical cells
165
possible destinies of a cell (3)
1. remain alive + functioning without dividing
2. grow + divide
3. die
166
necrosis
pathological type of cell death resulting from tissue injury
167
meiosis
the reproductive cell division that occurs in the gonads, produces gamets in which the number of chromosomes is reduced by half
168
haploid (n) cells
cells that contain a single set of 23 chromosomes (gametes)
fertilization restores diploid #
169
meiosis I
homologous chromosomes undergo synapsis (pairing) and crossing over; the net result is 2 haploid cells that are genetically unlike each other and starting diploid parent cell that produced them
170
meiosis II
2 haploid cells divide to form haploid cells
171
genetic recombination
the formation of new combinations of genes
accounts for great genetic variation betw humands and other organisms that form gametes vis meiosis
171
crossing-over
parts of the chromatids of 2 homologous chromosomes are exchanged with each other (Meiosis I)
172
cells vary a lot in...
shape + size
173
cell size
1 um = 10^-(6) m
140 um - 8 um
174
cell shape
is related to its function
round, oval, flat, cube-shaped, column-shaped, elongated, star-shaped, cylindrical, or disc-shaped
