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Pathology > The cell as a Unit of health and disease > Flashcards

The cell as a Unit of health and disease Flashcards

1
Q

Pathology literally translates as _______

A

The study of suffering

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2
Q

He was prescient in assrting that disease originates at the cellular level.

A

Virchow

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3
Q

Human genome contains some ________ billion DNA base pairs

A

3.2

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4
Q

Within the genome there are only about _____ protein-encoding proteins.

A

20000

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5
Q

These are the blueprints that instruct the assembly of enzymes, structural elements, and signalling molecules within the 50 trillion cells that make up the human body.

A

Noncoding DNA

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6
Q

___% of the human genome does not encode proteins

A

98.5

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7
Q

Regions that provide binding sites for transcription factors

A

Promoter and enhancer

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8
Q

2 best-studied varieties of noncoding regulatory RNA

A

MicroRNA

long noncoding RNA

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9
Q

jumping genes, can move around the genome during evolution, resulting in variable copy number and positioning even among closely related species.

A

mobile genetic elements

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10
Q

special structural regions of DNA

-chromosome ends

A

telomeres

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11
Q

special structural regions of DNA

-chromosome tethers

A

centromeres

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12
Q

Major component of centromere

A

satellite DNA

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13
Q

is also important in maintaining the dense, tightly packed organization of heterochromatin

A

satellite DNA

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14
Q

T or F
Variation in gene regulation may prove to be more important in disease causation than structural changes in specific proteins

A

True

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15
Q

Individual variation, including differential susceptibility to diseases and environmental stimuli, is encoded in less than __% of our DNA

A

0.5

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16
Q

2 of the most common forms of DNA variation in the human genome

A
  1. SNP

2. CNV

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17
Q

Variants at single nucleotide positions and are almost always biallelic

A

SNP

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18
Q

Roughly ___% of SNPs occur in coding regions

A

1

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19
Q

T or false
SNPs located in noncoding regions can occur within
genomic regulatory elements, thereby altering gene
expression; in such instances, SNPs influence disease
susceptibility directly.

A

T

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20
Q

are thought
to have no effect on gene function or individual
phenotype.

A

Neutral variants

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21
Q

are a form of genetic variation consisting of different
numbers of large contiguous stretches of DNA; these
can range from 1000 base pairs to millions of base pairs.

A

CNVs

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22
Q

Approximately __% of CNVs involve gene-coding
sequences; thus CNVs may underlie a large portion
of human phenotypic diversity.

A

50

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23
Q

Nucleosomes consist
of DNA segments 147 bp long that are wrapped around
a central core structure of highly conserved low molecular
weight proteins called ____

A

histones.

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24
Q

. The naked DNA of a single human cell is about

___long

A

1.8 m

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25
Q

In
general, only the regions that are ____ are available
for transcription.

A

“unwound”

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26
Q

T or False

Histones are static

A

False
Histones are not static, but rather are highly dynamic
structures regulated by a host of nuclear proteins.

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27
Q

____ complexes, on the other hand, carry out over 70
different histone modifications generically denoted as
“marks.”

A

“Chromatin

writer”

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28
Q

are associated with histone marks that make the DNA accessible
to RNA polymerases.

A

Actively transcribed genes

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29
Q

____ have

histone marks that enable DNA compaction into heterochromatin

A

inactive genes

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30
Q

Histone marks are reversible through the

activity of ____

A

“chromatin erasers.”

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31
Q

Histone methylation. Both ___ and ___can be

methylated by specific writer enzymes.

A

lysines; arginines

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32
Q

Lysine residues are acetylated by _____, whose modifications
tend to open the chromatin and increase transcription.

A

histone acetyltransferases (HATs)

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33
Q

changes can be reversed by histone deacetylases (HDACs), leading to chromatin ____

A

condensation.

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34
Q

Histone phosphorylation. ____residues can be modified

by phosphorylation

A

Serine

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35
Q

High levels of DNA methylation in

gene regulatory elements typically result in ____

A

transcriptional

silencing

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36
Q

are believed to bind to noncoding
regions and control long-range looping of DNA, thus
regulating the spatial relationships between enhancers
and promoters that control gene expression.

A

Chromatin organizing factors

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37
Q

T or F

Genes can also be regulated by noncoding RNAs.

A

True

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38
Q

do not encode proteins; they modulate translation

of target messenger RNAs (mRNAs)

A

Micro-RNA

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39
Q

T or F
Posttranscriptional
silencing of gene expression by miRNA is a fundamental
and well-conserved mechanism of gene regulation present
in all prokaryotes

A

False

-Eukaryotes

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40
Q

The human genome encodes almost ____ miRNA genes

A

6000

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41
Q

_____ are short RNA sequences

that can be introduced experimentally into cells where they

A

Small interfering RNAs (siRNAs)

42
Q

finer granular structures of the nucleus

A

Euchromatin

43
Q

means

that histones are not tightly wound.

A

Finely granular chromatin

44
Q 
■ cytochemically dense and
transcriptionally inactive (they
are not transcribed)
■ Coarsely granular structures of
the nucleus
A

HETEROCHROMATIN

45
Q

■ cytochemically dispersed and
transcriptionally active
■ Finely granular structures of the
nucleus

A

EUCHROMATIN

46
Q

Functions primarily to modulate the translation of

target mRNA into their corresponding proteins

A

Micro-RNA (miRNA)

47
Q

Transcription of miRNA genes produces a
primary transcript (pri-miRNA) that is
processed into progressively smaller segments,
including trimming by the ___

A

Dicer

48
Q

they serve as
substrates for Dicer and interact with RISC,
thereby reproducing endogenous miRNAs
function.

A

Small interfering RNAs (siRNAs)

49
Q

The number of lncRNAs may exceed coding

mRNAs by 10- to 20- fold

A

LONG NON-CODING RNA (lncRNA)

50
Q

LONG NON-CODING RNA (lncRNA) modulate gene expression in many ways:

A

○ Gene activation
○ Gene suppression
○ Promote chromatin modification
○ Assembly of protein complexes

51
Q

T or F
Many normal housekeeping functions are
compartmentalized within membrane-bound
intracellular organelles

A

True

52
Q

synthesizes new proteins destined for
the plasma membrane or point beyond
which are physically assembled in the
Golgi apparatus

A

Rough endoplasmic reticulum (RER)

53
Q

Synthesizes proteins intended for the

cytosol

A

Free ribosomes

54
Q

SER may be abundant in ___ and ___
where it is used for steroid hormone and
lipoprotein synthesis;

A

gonads; liver

55
Q

“Disposal” complexes that degrade
denatured or otherwise “tagged”
cytosolic proteins.

-can trigger initiation or suppression of signalling pathways

A

PROTEASOMES

56
Q 
Are intracellular organelles containing
degradative enzymes that permit
digestion of a wide range of
macromolecules (proteins,
polysaccharides, lipids, and nucleic
acids.
A

LYSOSOMES

57
Q 
○ Contain catalase, peroxidase, and other
oxidative enzymes
○ They play a specialized role in the
breakdown of very long-chain fatty
acids, generating hydrogen peroxide in
the process.
A

PEROXISOMES

58
Q

Shuttle internalized material to the

appropriate intracellular sites

A

Endosomal vesicles

59
Q

Most of the adenosine triphosphate
(ATP) that powers cells is generated
via_____

A

Mitochondrial oxidative phosphorylation

60
Q

also serve as an important source of
metabolic intermediates needed for
anabolic metabolism

A

Mitochondria

61
Q

contain important sensors of cell
damage that can initiate and regulate
programmed cell death (e.g.,
apoptosis).

A

Mitochondria

62
Q

Movement of both organelles and proteins within
the cell, as well as the entire cell in its
environment is accomplished by the
_____

A

cytoskeleton.

63
Q

Cytoskeleton is composed of:

A

Filamentous actins (microfilaments), Keratins(intermediate filaments), and microtubules

64
Q

○ 5 to 9nm diameter
○ formed from the globular protein actin
(G-actin)
○ most abundant

A

Actin microfilaments

65
Q

New subunits are typically added at the
“positive” end of the strand and
removed from the “negative” end—a
process referred to as____

A

actin

treadmilling

66
Q 
○ 10nm diameter
○ predominantly form ropelike polymers
and do not usually actively reorganize
like actin and microtubules
○ provide tensile strength so that cells
can bear mechanical stress, e.g., in
epithelia
○ They form the major structural proteins
of skin and hair.
A

Intermediate filaments

67
Q

in mesenchymal

cells

A

Vimentin

68
Q

in muscle cells forms
the scaffold on which actin
and myosin contract.

A

Desmin

69
Q

are critical for
neuronal axon structure and
confer both strength and
rigidity.

A

Neurofilaments

70
Q

is expressed in glial cells

A

Glial fibrillary acidic protein

71
Q

are expressed in

epithelial cells

A

cytokeratins

72
Q 
are
intermediate filament proteins
that form the nuclear lamina,
define nuclear shape, and
can regulate transcription.
A

Lamins (A, B, and C) 7

73
Q 
○ 25nm thick
○ composed of noncovalently polymerized
α- and β-tubulin dimers organized into
hollow tubes
○ These fibrils are extremely dynamic
and polarized, with “+” and “−” ends.
A

Microtubules

74
Q 
is typically embedded
in a microtubule organizing
center (MTOC or centrosome)
near the nucleus, where it is
associated with paired
centrioles
A

“−” end

75
Q

elongates or recedes
in response to various stimuli by
the addition or subtraction of
tubulin dimers

A

“+” end

76
Q

anterograde (− to

+)

A

Kinesins

77
Q

retrograde (+ to −)

A

Dyneins

78
Q 
PLASMA MEMBRANE
● a fluid bilayer of amphipathic phospholipids —
hydrophilic head groups that face the
\_\_\_\_\_ and hydrophobic lipid
tails that \_\_\_\_\_\_
A

aqueous environment; interact with each other

79
Q

○ inner membrane leaflet
○ serving as an electrostatic scaffold for
intracellular proteins

A

PHOSHATIDYLINOSITOL

80
Q 
polyphosphoinositides can be
hydrolyzed by \_\_\_\_\_\_to
generate intracellular second signals
like diacylglycerol and inositol
trisphosphate
A

phospholipase C

81
Q

○ inner face
○ confers a negative charge involved in
electrostatic protein interactions

A

PHOSPHATIDYLSERINE

82
Q

○ extracellular face
○ They are important in cell-cell and
cell-matrix interactions

A

GLYCOLIPIDS AND SPHINGOMYELIN

83
Q 
is involved in specialized
pathways of protein/lipid transport and
signaling. They also act as vesicular
carriers for membrane trafficking in T
lymphocytes.
A

Lipid raft

84
Q

that binds one

cell to another

A

Cell-adhesion molecule

85
Q 
special integral
membrane proteins called \_\_\_\_
form transmembrane channels for
water, H2O2, and other small
molecules.
A

aquaporins

86
Q 
T or F
Larger hydrophobic molecules, (e.g.,
steroid-based molecules like estradiol
or vitamin D) can also cross lipid
bilayers with relative impunity
A

True

87
Q

create hydrophilic
pores, which, when open, permit rapid
movement of solutes (usually restricted
by size and charge).

A

Channel proteins

88
Q 
bind their specific
solute and undergo a series of
conformational changes to transfer the
ligand across the membrane; their
transport is relatively slow.
A

Carrier proteins

89
Q

pumps polar compounds (e.g.,
chemotherapeutic drugs) out of cells
and may render cancer cells resistant to
treatment.

A

multidrug

resistance (MDR) protein

90
Q

causes net movement

of water out of the cells.

A

Hypertonicity

91
Q

causes net movement

of water into cells.

A

Hypotonicity

92
Q

_____are most active at pH 7.4
and are often regulated by Ca2+, whereas
_____ function best at pH 5
or less.

A

Cytosolic enzymes ; lysosomal enzymes

93
Q

○ For smaller molecules

○ “little caves”

A

Caveolae-mediated endocytosis

94
Q

the major structural
protein of caveolae, which, like
membrane rafts, are enriched in
glycosphingolipids and cholesterol.

A

Caveolin

95
Q

Internalization of caveolae along with
bound molecules and associated
extracellular fluid is called _____

A

potocytosis

96
Q 
Macromolecules bound to membrane
receptors (such as transferrin or
low-density lipoprotein [LDL] receptors)
are taken up at specialized regions of
the plasma membrane called
\_\_\_\_
A

clathrin-coated pits.

97
Q 
T or F
The vesicles then rapidly lose their
clathrin coating and fuse with a basic
intracellular structure called the early
endosome
A

False

-not acidic, basic

98
Q 
In this process, proteins synthesized
and packaged within the RER and
Golgi apparatus are concentrated in
secretory vesicles, which then fuse with
the plasma membrane to expel their
contents.
A

exocytosis

99
Q

is the movement of endocytosed
vesicles between the apical and
basolateral compartments of cells

A

Transcytosis

100
Q

Ganda ni quen no?

A

TRUE, siz!

Pathology (31 decks)

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