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Histology Lecture > MOD 1 UNIT 2: THE CELL (PART 1) > Flashcards

MOD 1 UNIT 2: THE CELL (PART 1) Flashcards

1
Q

Forms ribosomes

A

nucleolus

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2
Q

Separates the cell from its environment

A

plasma membrane

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3
Q

Acts as the cell’s digestive system

A

lysosome

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4
Q

Acts as protein factory

A

ribosome

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5
Q

Contains organelles

A

cytoplasm

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6
Q

Contains DNA

A

nucleus

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7
Q

Act as power plants of the cell

A

mitochondria

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8
Q

Classified both smooth and rough

A

endoplasmic reticulum

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9
Q

Smallest cell fibers for support

A

microfilaments

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10
Q

Thickest of cell fibers with tiny, hollow tubes for support

A

microtubules

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11
Q

basic structural and functional unit of the body

A

cell

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12
Q

TRUE OR FALSE

All living organism does not contain a multitude of cell types, whose main function are to
maintain a proper homeostasis in the body, which is maintaining the internal environment
of the body in a relatively constant state.

A

FALSE

“contain a multitude of cell types”

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13
Q

largest organelle of the cell and contains the genetic material encoded in the
deoxyribonucleic acid (DNA) of chromosomes.

A

NUCLEUS

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14
Q

TRUE OR FALSE

The nucleus directs protein synthesis in the cytoplasm via ribosomal ribonucleic acid
(rRNA), messenger RNA (mRNA), and transfer RNA (tRNA). All forms of RNA are synthesized
in the nucleus.

A

TRUE

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15
Q

a double membrane structure consisting of a perinuclear cistern between the
inner and the outer nuclear membranes, this protects the genetic
material and separates it from the diverse molecules and structures of the cytoplasm.

A

Nuclear envelope

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16
Q

TRUE OR FALSE

The nuclear envelope is continuous with the rough endoplasmic reticulum.

A

TRUE

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17
Q

This membrane is about 6 nanometers (nm) thick and it faces the cytoplasm

A

Outer nuclear membrane

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18
Q

A loosely arranged mesh of intermediate filaments surrounds the outer nuclear
membrane on its cytoplasmic aspect

A

vimentin

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19
Q

stud the cytoplasmic surface of the outer nuclear membrane, they synthesize proteins that enter the perinuclear cisterna.

A

ribosome

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20
Q

Is about 6 nm thick, it faces the nuclear material but is separated from it and is supported on its inner surface by the nuclear lamina, fibrous lamina that is 80 to 300 nm thick and composed primarily of lamins A, B, and C.

A

Inner nuclear membrane

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21
Q

TRUE OR FALSE

Phosphorylation of lamins leads to disassembly, and dephosphorylation results in
reassembly of the nuclear envelope.

A

TRUE

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22
Q

It is located between the inner and outer nuclear membranes and is 20 to 40 nm wide, this is also perforated by nuclear pores at various locations

A

perinuclear cisterna

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23
Q

average 80 nm in diameter and number from dozens to thousands depending upon metabolic activity of the cell, they are formed by fusion of the inner and outer nuclear membranes.

A

nuclear pores

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24
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

nuclear pores do not permit passage of certain molecules in either direction between the nucleus and the cytoplasm via a 9-nm channel opening

NPCs are aided in communicating with each other by the nuclear lamina

A

“B”

first statement, “nuclear pores permit passage”

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25
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

The NPC is composed of nearly 100 proteins, some of which are arranged in
eightfold symmetry around the margin of the pore.

The nucleoplasmic side of the pore exhibits a nuclear basket, whereas the cytoplasmic side displays fibers extending into the
cytoplasm.

A

“C”

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26
Q

is believed to be responsible for transporting proteins into and out of the nucleus via?

A

receptor-mediated transport

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26
Q

is located around the cytoplasmic margin of the nuclear pore and is composed of eight subunits, each possessing a cytoplasmic filament composed of a Ran-binding protein (GTP-binding protein) extending into the cytoplasm.

A

cytoplasmic ring

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26
Q

is located around the nucleoplasmic margin of the nuclear pore and is composed of eight subunits

A

nucleoplasmic ring

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26
Q

Attached to the distal end of the nuclear basket is the ________?

A

distal ring

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27
Q

TRUE OR FALSE

Distal ring is the outermost ring assists in the export of RNA into the cytoplasm.

A

FALSE

“innermost”

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27
Q

is interposed between the cytoplasmic and nucleoplasmic rings

A

luminal ring

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27
Q

TRUE OR FALSE

A structure described by some as the hourglass-shaped transporter or central plug in the
center of the luminal ring is believed to be cargo being transported through the NPC rather
than a structural component of the NPC.

A

TRUE

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27
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

The NPC permits passive movement across the nuclear envelope via a 9- to 11-
nm open channel for simple diffusion. Most proteins, only large of size, pass in either
direction only by receptor-mediated transport.

These proteins have clusters of certain
amino acids known as nuclear localization segments (NLS) that act as signals for transport.

A

“B”

first statement, “regardless of size”

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27
Q

Transport mechanisms involve a group of proteins, the function of these proteins is regulated by Ran, a group of guanosine triphosphate–binding proteins.

A

exportins and importins

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27
Q

facilitates the shuttling of cargo in
both directions

A

nucleoporins

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28
Q

Transport signals of nucleoporins

A

nucleocytoplasmic shuttling (NS)
signals.

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28
Q

These gaps in the nuclear envelope are bridged by a pore complex of numerous
proteins, their structure controls the traffic of molecules and particles between the nucleus
and the cytoplasm.

A

nuclear pore

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28
Q

This tightly coiled chromatic in a more extended form, accessible to transcription,
and it appears as basophilic clumps in specimens prepared for light microscopy.

A

Heterochromatin

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28
Q

This is chromatin in a more extended form, accessible to transcription. In the light
microscope, it appears as less densely stained, basophilic regions of the nucleus.

A

Euchromatin

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29
Q

One or more of these spherical, basophilic structures develop in the nucleus if the
cells are generating ribosomes.

A

Nucleolus

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29
Q

is a nuclear inclusion that is not surrounded by a membrane

A

nucleolus

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29
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

nucleus is observed in interphase cells that are actively synthesizing proteins;

only one nucleolus can be present in the nucleus.

A

“D”

first statement, “nucleolus”
second statement, “more than one”

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29
Q

portions of the
chromosomes (in humans, chromosomes 13, 14, 15, 21, and 22) where rRNA genes are
located

A

nucleolar organizer regions (NORs)

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30
Q

are composed of inactive DNA, where DNA is not being transcribed; NORs are also located here.

A

Fibrillar centers

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30
Q

is composed of 5-nm fibrils surrounding the fibrillar centers and contains transcriptionally active DNA and the rRNA precursors that are being transcribed.

A

pars fibrosa

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31
Q

is composed of 15-nm maturing ribosomal precursor particles.

A

pars granulosa

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31
Q

is a fiber network participating in the organization of the nucleolus.

A

Nucleolar matrix

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31
Q

is involved in the synthesis of rRNA and its assembly into ribosome precursors, also sequesters certain nucleolar proteins that function as cell cycle checkpoint signaling proteins.

A

nucleolus

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31
Q

is the protoplasm within the nuclear envelope, it consists of a matrix and various types of particles.

A

nucleoplasm

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32
Q

acts as a scaffold that aids in organizing the nucleoplasm.

A

nuclear matrix

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32
Q

are involved in the transcription and processing of mRNA and rRNA, steroid receptor-binding sites, carcinogen-binding sites, heat shock proteins, DNA viruses, viral proteins (T antigen)

A

nucleoplasm

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32
Q

is continuous with the endoplasmic reticulum (ER) of the cytoplasm and the nuclear envelope.

A

nucleoplasmic reticulum

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32
Q

TRUE OR FALSE

nucleoplasmic reticulum contains nuclear calcium functioning within the
nucleus and possesses receptors for inositol 1,4,5-trisphosphate, regulating calcium signals
within compartments of the nucleus related to gene transcription, protein transport, and
perhaps other functions.

A

TRUE

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32
Q

are clusters of irregularly distributed particles (20–25 nm in diameter) that contain RNP and various enzymes.

A

Interchromatin granules

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33
Q

are single dense granules (30–50 nm in diameter) surrounded by a less-dense halo.

A

Perichromatin granules

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33
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

perichromatin may represent messenger RNPs (mRNPs).

The number of granules increases in liver cells exposed to carcinogens or
temperatures above 37°C.

A

“C”

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33
Q

are complexes of precursor mRNA (pre-mRNA) and proteins and are involved in processing of pre-mRNA.

A

hnRNP particles

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33
Q

are complexes of proteins and small RNAs and are involved in hnRNP splicing or in cleavage reactions.

A

Small nuclear RNPs (snRNPs)

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34
Q

consists of double-stranded DNA complexed with histones and acidic proteins.

A

Chromatin

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34
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

chromatin does not resides within the nucleus as heterochromatin and euchromatin.

The euchromatin/heterochromatin ratio is higher in malignant cells than in normal cells.

A

“B”

first statement, “chromatin resides”

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35
Q

condensed inactive chromatin, is concentrated at the periphery of the nucleus and around the nucleolus and scattered throughout the nucleoplasm.

A

Heterochromatin

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35
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

Although heterochromatin is transcriptionally inactive, recent evidence indicates
that it plays a role in interchromosomal interactions and chromosomal segregation during meiosis.

Euchromatin corresponds to one of two X chromosomes and is therefore
present in nearly all somatic cells of female mammals.

A

“A”

second statement, “Heterochromatin corresponds”

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35
Q

During interphase, the inactive X
chromosome is visible as a dark-staining body within the nucleus. This structure is called the

A

Barr body or sex chromatin

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36
Q

is the transcriptionally active form of chromatin that appears in the LM as a lightly stained region of the nucleus.

A

Euchromatin

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36
Q

TRUE OR FALSE

Euchromatin appears in transmission electron microscope (TEM) as electron-lucent regions among heterochromatin and is composed of 30-nm strings of nucleosomes and the DNA double helix.

A

TRUE

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36
Q

TRUE OR FALSE

Chromatin is responsible for RNA synthesis.

A

TRUE

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36
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

Chromosomes consist of chromatin extensively folded into loops; this
conformation is maintained by DNA-binding proteins.

Each chromosome contains a single
DNA molecule and associated proteins

A

“C”

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37
Q

structural unit of chromatin packaging

A

nucleosomes

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37
Q

are visible with the LM only during mitosis and
meiosis, when their chromatin condenses

A

chromosomes

37
Q

forms the nucleosome core, around which the DNA double helix is wrapped two full turns.

A

extended chromatin

37
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

The nucleosome core consists of two copies each of histones H2A, H2B, H3, and
H4.

Nucleosomes are spaced at intervals of 100 base pairs.

A

“A”

second statement, “200 base pairs”

37
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

When viewed with TEM, extended chromatin resembles beads on a string

the beads represent nucleosomes and the string represents linker DNA.

A

“C”

38
Q

TRUE OR FALSE

Nucleosomes does not support DNA and regulate its accessibility for
replication and transcription as well as for its repair.

A

FALSE

“nucleosomes supports DNA”

38
Q

this contains an additional histone, H1, which wraps around groups of nucleosomes

A

condensed chromatin

38
Q

is observed in chromosomes during mitosis after staining with Giemsa, which
is specific for DNA sequences rich in adenine (A) and thymine (T)

A

G-banding

38
Q

TRUE OR FALSE

Banding is thought to
represent highly folded DNA loops.

A

TRUE

39
Q

TRUE OR FALSE

G-banding is characteristic for each species and is used to identify chromosomal anomalies.

A

TRUE

40
Q

refers to the number and morphology of chromosomes and is characteristic
for each species

A

Karyotype

40
Q

is the number of chromosomes in germ cells (23 in humans)

A

haploid number (n)

40
Q

is the number of chromosomes in somatic cells (46 in humans)

A

diploid number (2n)

40
Q

the total genetic complement of an individual, is stored in its chromosomes

A

Genome

41
Q

TRUE OR FALSE

the genome consists of 22 pairs of autosomes and 2 pair of sex chromosomes
(either XX or XY), totaling 23 pairs, or 46 chromosomes.

A

FALSE

“1 pair of sex chromosomes”

41
Q

is a long double-stranded linear molecule composed of multiple nucleotide
sequences. It acts as a template for the synthesis of RNA

A

DNA

41
Q

are composed of a base (purine or pyrimidine), a deoxyribose sugar, and a phosphate group.

A

nucleotides

41
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

  1. The purines are cytosine (C) and thymine (T). .
  2. The pyrimidines are adenine (A) and guanine (G).
A

“D”

first statement, “The purines are adenine (A) and guanine (G).”

second statement, “The pyrimidines are cytosine (C) and thymine (T)”

42
Q

consists of two complementary DNA strands held together by
hydrogen bonds between the base pairs A-T and G-C.

A

DNA double helix

43
Q

are regions of the DNA molecule that code for specific RNAs

A

exons

43
Q

are regions of the DNA molecule, between exons, that do not code for RNAs

A

introns

44
Q

TRUE OR FALSE

A codon is a sequence of three bases in the DNA molecule that codes for multiple
amino acid.

A

FALSE

“single amino acid”

45
Q

TRUE OR FALSE

A gene is a segment of the DNA molecule that is responsible for the formation of a single
RNA molecule.

A

TRUE

46
Q

TRUE OR FALSE

According to the Human Genome Study, there are approximately 10,000 genes in the
human genome.

A

FALSE

“25,000 genes”

47
Q

is a linear molecule similar to DNA; however, it is single stranded and contains ribose
instead of deoxyribose sugar and uracil (U) instead of thymine (T).

A

RNA

48
Q

TRUE OR FALSE

Transcription is catalyzed by three RNA polymerases: I for rRNA, II for mRNA, and III for tRNA.

A

TRUE

49
Q

carries the genetic code to the cytoplasm to direct protein synthesis

A

mRNA

50
Q

TRUE OR FALSE

one start codon (AUG) for initiating protein synthesis and one of three stop codons (UAA, UAG, or UGA) for terminating protein synthesis.

A

TRUE

51
Q

is folded into a cloverleaf shape and contains approximately 80 nucleotides,
terminating in adenylic acid (where amino acids attach).

A

tRNA

52
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

Each tRNA combines with a specific amino acid that has not been activated by an enzyme.

the anticodon
ensures that the tRNA transfers its activated amino acid molecule in the proper sequence
to the growing polypeptide chain.

A

“B”

first statement, “has been activated”

53
Q

a triplet of nucleotides that
recognizes the complementary codon in mRNA.

A

anticodon

54
Q

associates with many different proteins (including enzymes) to form
ribosomes.

A

rRNA (ribosomal RNA)

55
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

rRNA associates with mRNA and tRNA during protein synthesis.

rRNA synthesis takes place in the nucleolus and is catalyzed by RNA polymerase I.

A

“C”

56
Q

Pre-rRNA associates with ribosomal proteins and is cleaved into the three sizes, ___ ___ ___ ?

A

(28S, 18S, and 5.8S)

57
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

The RNP containing 28S and 5.8S rRNA then combines with 5S rRNA, which is
synthesized outside of the nucleolus, to form the small subunit of the ribosome.

The RNP containing 18S rRNA forms the large subunit of the ribosome.

A

“D”

first statement, “large subunit”

second statement, “small subunit”

58
Q

varies in length in different types of cells but is repeated each time a cell divides. It is composed of a series of events that prepare the cell to divide into two daughter cells.

A

cell cycle

59
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

cell cycle is temporarily suspended in nondividing resting cells (e.g., peripheral lymphocytes),
which are in the G0 state.

Such cells may reenter the cycle and begin to divide again.

A

“C”

60
Q

TRUE OR FALSE

cell cycle is permanently interrupted in differentiated cells that do not divide (e.g., cardiac muscle cells and neurons).

A

TRUE

61
Q

is considerably longer than the M phase and is the period during which the
cell doubles in size and DNA content.

A

interphase

62
Q

Interphase is divided into three separate phases __ __ __ ?

A

G1, S, and G2

63
Q

lasts for hours to several days, occurring after mitosis, it is the period during which the cell
grows and proteins are synthesized, restoring the daughter cells to normal volume and size.

A

G1 phase (gap one phase)

64
Q

Cells that fail to reach the restriction point become resting cells and enter the ____?

A

G0 (outside phase) state

65
Q

lasts 8 to 12 hours in most cells, DNA is replicated and proteins are synthesized, resulting in duplication of the chromosomes.

A

S phase (synthetic phase)

66
Q

TRUE OR FALSE

Centrosomes are also duplicated during G1 phase

A

FALSE

“during S phase”

67
Q

lasts 2 to 4 hours, this phase follows the S phase and extends to mitosis.

A

G2 phase (gap two phase)

68
Q

TRUE OR FALSE

During G2 phase, the cell prepares to divide, the centrioles grow to maturity,
energy required for the completion of mitosis is stored

A

TRUE

69
Q

which initiate and/or induce
progression through the cell cycle

A

cyclins/cyclin-dependent kinases (CDKs)

70
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

During the G1 phase, cyclins D and E bind to their respective CDKs

these complexes enable the cell to enter and advance through the S phase.

A

“C”

71
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

Cyclin A binds to its CDKs, thus enabling the cell to leave the S phase and enter the G2 phase as well as to manufacture cyclin B.

Cyclin B binds to its CDK, inducing the cell to leave the G2 phase and
enter the M phase.

A

“C”

72
Q

lasts 1 to 3 hours. It follows the G2 phase and completes the cell cycle.

A

Mitosis

73
Q

TRUE OR FALSE

Division of the nucleus (karyokinesis) and cytoplasm (cytokinesis) results in the production of two identical daughter cells.

A

TRUE

74
Q

begins when the chromosomes condense, the nucleolus and nuclear envelope begin to disappear.

A

prophase

75
Q

contains centrioles and a pericentriolar cloud of material containing tubulin rings. It is the principal microtubule-organizing center (MTOC)
of the cell.

A

centrosome

76
Q

TRUE OR FALSE

During prophase, chromosomes consist of two parallel sister chromatids (future daughter
chromosomes) attached at the centromere, a constriction along the
chromosome.

A

TRUE

77
Q

TRUE OR FALSE

Kinetochores develop at the centromere region and function as
MTOCs.

A

TRUE

78
Q

begins when the nuclear envelope disappears, allowing the chromosomes to disperse apparently randomly in the cytoplasm.

A

Prometaphase

79
Q

The kinetochores complete development and attach to specific spindle
microtubules, forming ____

A

kinetochore microtubules

80
Q

Spindle microtubules that do not attach to kinetochores are called

A

polar microtubules

81
Q

is the phase during which the duplicated condensed chromosomes align at
the equatorial plate of the mitotic spindle and become attached to spindle microtubules
at their kinetochore.

A

metaphase

82
Q

begins as the chromatids separate at the centromere and daughter chromosomes move to opposite poles of the cell.

A

anaphase

83
Q

TRUE OR FALSE

During prophase, the spindle elongates.

A

FALSE

“During anaphase”

84
Q

TRUE OR FALSE

In the later stages of anaphase, a cleavage furrow begins to form around the cell as the contractile ring, a band of actin filaments, contracts.

A

TRUE

85
Q

is characterized by each set of chromosomes reaching the pole, a deepening of the cleavage furrow; the midbody (containing overlapping polar microtubules) is now between the newly forming daughter cells.

A

Telophase

86
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

During telophase, microtubules in the midbody are depolymerized, facilitating cytokinesis and
formation of two identical daughter cells.

The nuclear envelope is reestablished around the condensed chromosomes in the daughter cells, and nucleoli disappear.

A

“A”

second statement, “nucleoli reappear”

87
Q

is the method whereby cells are removed from tissues in an orderly fashion as a
part of normal maintenance or during development

A

Apoptosis (programmed cell death)

88
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

During apoptosis, they include chromatin condensation, breaking up of the nucleus, and blebbing of the plasma membrane.

The cell shrinks and is fragmented into membrane-enclosed fragments called apoptotic
bodies.

A

“C”

89
Q

Genes that code for enzymes, called

A

caspases

90
Q

TRUE OR FALSE

Defects in the process of programmed cell death do not contribute to many major diseases.

A

FALSE

“cell death contribute to many major diseases”

91
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

Excessive apoptosis causes extensive nerve cell loss in Alzheimer disease and stroke.

Insufficient apoptosis has been linked to cancer and other autoimmune diseases.

A

“C”

92
Q

is a special form of cell division in germ cells (oogonia and spermatozoa) in
which the chromosome number is reduced from diploid (2n) to haploid (n).

A

meiosis

93
Q

TRUE OR FALSE

DNA content of the original diploid cell is doubled (4n) in the S phase preparatory to
meiosis.

A

TRUE

94
Q

stages of meiosis

A

meiosis I (reductional division) and meiosis II (equatorial division).

95
Q

occurs after interphase during the cell cycle, when the DNA content is duplicated, whereas the chromosome number (46) remains unchanged, giving the cell a 4C DNA content

A

Reductional division (meiosis I)

96
Q

is divided into five stages (leptotene, zygotene, pachytene, diplotene, and diakinesis), also homologous maternal and paternal chromosomes pair via the
synaptonemal complex, forming a tetrad.

A

Prophase I

97
Q

Homologous pairs of chromosomes align on the equatorial plate of the
spindle in a random arrangement, facilitating genetic mixing.

A

Metaphase I

98
Q

This phase is similar to anaphase in mitosis except that each chromosome consists of two chromatids that remain held together.

A

Anaphase I

99
Q

is similar to telophase in mitosis in that the nuclear envelope is reestablished and two daughter cells are formed via cytokinesis.

A

Telophase I

100
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

During telophase I, each daughter cell now contains 23 chromosomes (n) number but has
a 2CDNA content (the diploid amount).

Each chromosome is composed of two similar sister chromatids (but genetically identical following recombination).

A

“A”

second statement, “not genetically identical”

101
Q

begins soon after the completion of meiosis I, following a brief interphase without DNA replication.

A

Equatorial division (meiosis II)

102
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

The stages of meiosis II are similar to those of mitosis; thus, the stages are named
similarly (prophase II, metaphase II, anaphase II, and telophase II).

Meiosis II occurs more rapidly than mitosis.

A

“C”

103
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

The cytoplasm contains three main structural components: organelles, inclusions, and the
cytoskeleton.

The functional interactions among
certain organelles result in the uptake and release of material by the cell, protein synthesis,
and intracellular digestion.

A

“C”

104
Q

The fluid component in cytoplasm is called

A

cytosol

105
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

Organelles are metabolically inactive units of cellular matter.

The plasma membrane, which envelops the cell and forms a boundary between it and
adjacent structures

A

“B”

first statement, “metabolically active”

106
Q

is a cluster of ribosomes along a single strand of messenger ribonucleic acid (mRNA) that is engaged in the synthesis of protein.

A

polyribosome (polysome)

107
Q

are the sites where mRNA is translated into protein.

A

Ribosomes

108
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

Proteins destined for transport (secretory, membrane, and lysosomal) are synthesized on
polyribosomes bound to the cytosol

whereas proteins not destined for transport are
synthesized on polyribosomes in the RER.

A

“D”

first statement, “destined, RER”

second statement, “not destined, cytosol”

109
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

The small ribosomal subunit binds mRNA and activated transfer ribonucleic acids (tRNAs)

an initiator tRNA recognizes the start codon (AUG) on the mRNA.

A

“C”

110
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

The small ribosomal subunit then binds to the complex.

Peptidyl transferase in the
large subunit catalyzes peptide bond formation, resulting in addition of amino acids to
the growing polypeptide chain.

A

“B”

first statement, “large ribosomal subunit”

111
Q

TRUE OR FALSE

A chain-terminating codon (UAA, UAG, or UGA) causes release of the
polypeptide from the ribosome, and the ribosomal subunits dissociate from the
mRNA.

A

TRUE

112
Q

This is formed by the alignment of several ribosomes along the length of an mRNA
molecule.

A

POLYRIBOSOME

113
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

When an mRNA for a cytosolic or mitochondrial protein is being translated, the
polyribosome is associated with endoplasmic reticulum,

it is suspended in the
cytosol as a free polyribosome.

A

“B”

first statement, “is not associated with endoplasmic reticulum”

114
Q

is where membrane-packaged proteins are synthesized, including
secretory, plasma membrane, and lysosomal proteins. This also monitors the
assembly, retention, and even degradation of certain proteins.

A

Rough endoplasmic reticulum (RER)

115
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

The interior region of RER is
called the cisterna, or the lumen.

RER is abundant in cells synthesizing secretory proteins; in such cells, the RER is disorganized
into many parallel arrays.

A

“A”

second statement, “RER is organized”

116
Q

The receptors of RER membrane is called

A

Ribophorins

117
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

The RER sac closest to the Golgi apparatus gives rise to buds free of ribosomes that form
vesicles.

It is known as a transitional element.

A

“C”

118
Q

processes membrane-packaged proteins synthesized in the RER and also recycles and redistributes membranes.

A

Golgi apparatus

119
Q

are disk-shaped and slightly curved, with flat centers and dilated rims, but
their size and shape vary.

A

cisternae

120
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

The cis face of the Golgi apparatus typically lies deep in the cell toward the nucleus
next to the RER.

The trans face of the Golgi apparatus lies at the side of the stack facing the plasma
membrane and is associated with vacuoles and secretory granules.

A

“C”

121
Q

Its outermost cisterna is associated with a network of interconnected tubes
and vesicles, called

A

vesicular–tubular clusters (VTC)

122
Q

Also called secretory granules, these are membrane-delimited packages of
secretory products that can be either stored in the cytoplasm or immediately secreted by
exocytosis of the vesicle at the cell surface.

A

secretory vesicle

123
Q

This is a membrane-delimited vesicle characterized by its low pH and the content of
a variety of hydrolases that can digest proteins, lipids, and polysaccharides.

A

Lysosome

124
Q

TRUE OR FALSE

Lysosomes are dense membrane-bound organelles of diverse shape and size
that function to degrade material.

A

TRUE

125
Q

A- FIRST TRUE
B- SECOND TRUE
C- BOTH TRUE
D- BOTH FALSE

Lysosomes may be identified in sections of tissue by cytochemical staining for acid phosphatase.

Lysosomes possess special membrane proteins and approximately 50 acid hydrolases, which are synthesized in the RER.

A

“C”

Histology Lecture (4 decks)

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