WorksheetsAP bio Ch 11-13
Total questions: 95
Worksheet time: 48mins
In yeast signal transduction, a yeast cell releases a mating factor which _____.
acts back on the same cell that secreted the mating factor, changing its development
passes through the membranes of neighboring cells, binds to DNA, and initiates transcription
binds to receptors on the membranes of other types of yeast cells
diffuses through the membranes of distant cells, causing them to produce factors that initiate long-distance migrations
Which of the following is a type of local signaling in which a cell secretes a signal molecule that affects neighboring cells?
hormonal signaling
autocrine signaling
paracrine signaling
Hormones are chemical substances produced in one organ that are released into the bloodstream and affect the function of a target organ. For the target organ to respond to a particular hormone, it must _____.
modify its plasma membrane to alter the hormone entering the cytoplasm
be from the same cell type as the organ that produced the hormone
experience an imbalance that disrupts its normal function
have receptors that recognize and bind the hormone molecule
When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway?
relay molecule
transducer
signal molecule
response molecule
Which of the following types of signaling is represented in the figure?
autocrine
paracrine
hormonal
synaptic
A G-protein receptor with GTP bound to it _____.
is in its active state
signals a protein to maintain its shape and conformation
will use cGMP as a second messenger
directly affects gene expression
Testosterone (a hormone) functions inside a cell by _____.
acting as a signal receptor that activates tyrosine kinases
binding with a receptor protein that enters the nucleus and activates specific genes
acting as a steroid signal receptor that activates ion channel proteins
coordinating a phosphorylation cascade that increases spermatogenesis (sperm generation)
One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this?
G protein-coupled receptors
ligand-gated ion channels
steroid receptors
receptor tyrosine kinases
A drug designed to inhibit the response of cells to testosterone (a hormone) would most likely result in _____.
lower cytoplasmic levels of cAMP
a decrease in transcriptional activity of certain genes
an increase in cytosolic calcium concentration
a decrease in G protein activity
Binding of a signaling molecule to which type of receptor leads directly to a change in the distribution of ions on opposite sides of the membrane?
receptor tyrosine kinase
G protein-coupled receptor
ligand-gated ion channel
intracellular receptor
Lipid-soluble signaling molecules, such as testosterone, cross the membranes of all cells but affect only target cells because _____.
only target cells retain the appropriate DNA segments
intracellular receptors are present only in target cells
only target cells possess the cytosolic enzymes that transduce the testosterone
only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor
If an animal cell suddenly lost the ability to produce GTP, what might happen to its signaling system?
It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
It would be able to carry out reception and transduction but would not be able to respond to a signal.
It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
It would employ a transduction pathway directly from an external messenger.
Which of the following would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins?
G protein-coupled receptor binding
ligand-gated ion channel signaling
adenylyl cyclase activity
receptor tyrosine kinase activity
The receptors for steroid hormones are located inside the cell instead of on the membrane surface like most other signal receptors. This is not a problem for steroids because _____.
the receptors can be readily stimulated to exit and relocate on the membrane surface
steroids do not directly affect cells but instead alter the chemistry of blood plasma
steroid hormones are lipid soluble, so they can readily diffuse through the lipid bilayer of the cell membrane
steroids must first bond to a steroid activator, forming a complex that then binds to the cell surface
In general, a signal transmitted via phosphorylation of a series of proteins _____.
results in a conformational (structural) change to each protein
requires binding of a hormone to an intracellular receptor
activates a transcription event
generates ATP in the process of signal transduction
Adenylyl cyclase has the opposite effect of which of the following?
protein kinase
protein phosphatase
phosphodiesterase
phosphorylase
Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently consumed coffee would have increased levels of _____.
phosphorylated proteins
cAMP
adenylyl cyclase
activated G proteins
Which of the following is a correct association?
kinase activity and the addition of a tyrosine
phosphodiesterase activity and the removal of phosphate groups
GTPase activity and hydrolysis of GTP to GDP
adenylyl cyclase activity and the conversion of cAMP to AMP
Protein kinase is an enzyme that _____.
functions as a second messenger molecule
serves as a receptor for various signal molecules
activates or inactivates other proteins by adding a phosphate group to them
produces second messenger molecules
In signal transduction, phosphatases _____.
move the phosphate group of the transduction pathway to the next molecule of a series
prevent a protein kinase from being reused when there is another extracellular signal
amplify the second messengers such as cAMP
inactivate protein kinases and turn off the signal transduction
At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects?
Estrogen is produced in very large concentration by nearly every tissue of the body.
Each cell responds in the same way when steroids bind to the cell surface.
Estrogen is kept away from the surface of any cells not able to bind it at the surface.
Estrogen binds to specific receptors inside many kinds of cells, each with different responses.
Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because they _____.
amplify the original signal many times
are species specific
always lead to the same cellular response
counter the harmful effects of phosphatases
Cells use different signaling strategies to achieve different goals. In hormonal signaling _____.
numerous cells can receive and respond to a signal produced in their vicinity
the signal can be directed to a very specific target because a narrow space separates the target cell from the transmitting cell
specialized cells release hormone molecules into the circulatory system, permitting distant cells to be affected
special molecules are passed through cell junctions
A small molecule that specifically binds to a larger molecule is called a(n) _____.
α protein
ligand
protein kinase
competitive inhibitor
Receptors for signal molecules _____.
all work via protein kinases
are never found in the nucleus of a cell
may be found embedded in the plasma membrane, or found within the cytoplasm or nucleus
all work by opening ion channels
A G protein is active when _____.
GDP replaces GTP
it is bound by its ligand and transported to the nucleus
GTP is bound to it
it is phosphorylated by protein kinase
If a modified form of GTP that cannot be enzymatically converted to GDP were added to a culture of cells, the likely result would be _____.
the inactivation of ligand-gated ion channels
the inactivation of G-protein-linked signaling pathways
the inhibition of pathways stimulated by tyrosine-kinase receptors
that the activated G proteins would remain locked in the "on" position, transmitting signal even in the absence of a signaling molecule
The general name for an enzyme that transfers phosphate groups from ATP to a protein is _____.
protein dehydrogenase
protein phosphatase
protein kinase
protein cyclase
ATPgammaS is a form of ATP that cannot be hydrolyzed by enzymes. If this compound was introduced to cells so that it replaced the normal ATP present in the cell, which of the following would you predict?
an increase in the numbers of phosphorylated proteins in the cell
an increase in anabolic cellular reactions
a decrease in phosphorylated proteins in the cell
an increase in cell division
The source of phosphate for a phosphorylation cascade is _____.
cAMP
ATP
protein kinase
GTP
cAMP usually directly activates _____.
phosphodiesterase
receptor tyrosine kinases
G proteins
protein kinase A
A mutation in the active site of adenylyl cyclase that inactivates it would most likely lead to _____.
an increase in the amount of cAMP present in the cell
lower activity of protein kinase A
higher activity of protein kinase A
increased binding of adenylyl cyclase to the G protein that activates it
IP3 (inositol trisphosphate) is produced as a result of _____.
protein kinase A activation
Ca2+
the cleavage of a certain kind of phospholipid in the plasma membrane
phospholipase C
IP3 (inositol trisphosphate) acts by _____.
activating cAMP
phosphorylating signal receptors
activating DAG
opening Ca2+ channels
In liver cells, epinephrine stimulates the breakdown of glycogen. As the signal-transduction pathway progresses, _____.
the signal is reduced
the signal is amplified
the number of molecules involved decreases
the number of molecules involved remains constant
What is the final result of mitosis in a human?
genetically identical 2n somatic cells
genetically different 2n somatic cells
genetically identical 1n somatic cells
genetically identical 2n gamete cells
Scientists isolate cells in various phases of the cell cycle. They find a group of cells that have 1.5 times more DNA than G1 phase cells. The cells of this group are _____.
between the G1 and S phases in the cell cycle
in the G2 phase of the cell cycle
in the M phase of the cell cycle
in the S phase of the cell cycle
The first gap in the cell cycle (G1) corresponds to _____.
normal growth and cell function
the phase in which DNA is being replicated
the beginning of mitosis
the phase between DNA replication and the M phase
In human and many other eukaryotic species' cells, the nuclear membrane has to disappear to permit _____.
cytokinesis
the attachment of microtubules to kinetochores
the splitting of the centrosomes
the disassembly of the nucleolus
The mitotic spindle is a microtubular structure that is involved in _____.
splitting of the cell (cytokinesis) following mitosis
triggering the compaction and condensation of chromosomes
dissolving the nuclear membrane
separation of sister chromatids
Metaphase is characterized by _____.
splitting of the centromeres
aligning of chromosomes on the equator
separation of sister chromatids
cytokinesis
Some cells have several nuclei per cell. How could such multinucleated cells be explained?
The cell underwent repeated cytokinesis but no mitosis.
The cell underwent repeated mitosis with simultaneous cytokinesis.
The cell underwent repeated mitosis, but cytokinesis did not occur.
The cell had multiple S phases before it entered mitosis.
At which phase are centrioles beginning to move apart in animal cells?
anaphase
interphase
metaphase
prophase
Movement of the chromosomes during anaphase would be most affected by a drug that prevents _____.
nuclear envelope breakdown
shortening of microtubules
formation of a cleavage furrow
elongation of microtubules
Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle did the nucleus contain 6 picograms of DNA?
G1
S
G2
M
A cleavage furrow is _____.
a ring of vesicles forming a cell plate
the separation of divided prokaryotes
a groove in the plasma membrane between daughter nuclei
the space that is created between two chromatids during anaphase
In the figure above, which number represents DNA synthesis?
I
II
III
IV
In the figure above, at which of the numbered regions would you expect to find cells at metaphase?
I and IV
II only
III only
IV only
What phase of mitosis is being shown?
prophase
metaphase
anaphase
telophase
Which option best describes what is happening during this phase?
sister chromatids are being pulled apart
homologous chromosomes are being pulled apart
crossing over is occurring
DNA is condensing
What phase of mitosis is being shown?
prophase
metaphase
anaphase
telophase
Which of the following occurs during prophase of mitosis?
crossing over between nonsister chromatids
independent assortment
the nuclear envelop breaks down
chromosomes decondense
What phase of mitosis is being shown?
prophase
metaphase
anaphase
telophase
What phase of mitosis is being shown?
prophase
metaphase
anaphase
telophase
What happens during telophase of mitosis?
DNA decondenses
nuclear envelop reforms
crossing over
the cytoplasm is split
What part of the cell cycle occurred in order to separate these cells?
independent assortment
crossing over
cytokineses
synthesis
Mitosis results in haploid daughter cells.
true
false
The daughter cells of mitosis are genetically identical to each other.
true
false
The purpose of mitosis is to create gametes.
true
false
Crossing over occurs during prophase of mitosis.
true
false
The purpose of mitosis is for growth and to replace dead or damaged cells.
true
false
What is the arrow pointing to?
condensed DNA
chromatin
Spindle fibers
Cell plate
What is the purpose of growth factors?
to stimulate cells to divide
to regulate crossing over
to cause a cell into G0
to help chromosomes line up along the equator of the cell
Which option best describe density-dependent inhibition?
cells must attach to a surface in order to divide
cells will automatically stop dividing if they are given a growth hormone
cells that are too crowded will stop dividing
cells will continue with the cell cycle indefinitely
Which of the following are true about cancer cells?
cancer cell may not need growth factors to divide
cancer cells always go into the G0 phase
cancer cells are created by a process called transformation
cancer cells do not skip cell cycle checkpoints
Which type of tumor is usually characterized by being able to metastasize?
benign
malignant
Several organisms, primarily protists, have what are called intermediate mitotic organization. What is the most probable hypothesis about these intermediate forms of cell division?
They represent a form of cell reproduction, which must have evolved completely separately from those of other organisms.
They rely on totally different proteins for the processes they undergo.
They may be more closely related to plant forms that also have unusual mitosis.
They show some but not all of the evolutionary steps toward complete mitosis.
Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely _____.
an animal cell in the process of cytokinesis
a plant cell in the process of cytokinesis
an animal cell in the S phase of the cell cycle
a plant cell in metaphase
Neurons and some other specialized cells divide infrequently because they _____.
no longer have active nuclei
have entered into G0
can no longer bind Cdk to cyclin
show a drop in MPF concentration
Cyclin-dependent kinase (Cdk) is _____.
inactive, or "turned off," in the presence of cyclin
present only during the S phase of the cell cycle
the enzyme that catalyzes the attachment of chromosomes to microtubules
an enzyme that attaches phosphate groups to other proteins
What happens if MPF (mitosis-promoting factor) is introduced into immature frog oocytes that are arrested in G2?
Nothing happens.
The cells undergo meiosis.
The cells enter mitosis
Cell differentiation is triggered
Once a cell completes mitosis, molecular division triggers must be turned off. What happens to MPF during mitosis?
It is completely degraded
It is exported from the cell.
The cyclin component of MPF is degraded
The Cdk component of MPF is degraded and exported from the cell
A research team began a study of a cultured cell line. Their preliminary observations showed them that the cell line did not exhibit either density-dependent inhibition or anchorage dependence. What could they conclude right away?
The cells are unable to form spindle microtubules
They have altered the series of cell cycle phases
The cells show characteristics of tumors
They were originally derived from an elderly organism
For a chemotherapeutic drug to be useful for treating cancer cells, which of the following is most desirable?
It is safe enough to limit all apoptosis (cell death).
It does not alter metabolically active cells
It interferes with cells entering G0.
It interferes with rapidly dividing cells
Cells from advanced malignant tumors often have very abnormal chromosomes and an abnormal number of chromosomes. What might explain the association between malignant tumors and chromosomal abnormalities?
Cancer cells are no longer density-dependent
Cancer cells are no longer anchorage-dependent.
Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities.
Transformation introduces new chromosomes into cells
Asexual reproduction occurs during _____.
meiosis
mitosis
fertilization
chromosome exchange between organisms of different species
Quaking aspen can send out underground stems for asexual reproduction. Sexual reproduction is not as common, but when it does happen, the haploid gametes have 19 chromosomes. How many chromosomes are in the cells of the underground stems?
9
10
19
38
Which of the following is true of a species that has a chromosome number of 2n = 16?
The species is diploid with 32 chromosomes per cell
The species has 16 sets of chromosomes per cell.
Each diploid cell has eight homologous pairs
A gamete from this species has four chromosomes
Homologous chromosomes _____.
are identical
carry information for the same traits
carry the same alleles
align on the metaphase plate in meiosis II
The human X and Y chromosomes _____.
are both present in every somatic cell of males and females
are the same size and have the same number of genes
include genes that determine an individual's sex
are called autosomes
The karyotype shows the sex of this person is _____.
male
female
Which of the following happens at the conclusion of meiosis I?
Homologous chromosomes of a pair are separated from each other.
Sister chromatids are separated.
Four daughter cells are formed.
Daughter cells are genetically identical
Sister chromatids separate from each other during _____.
meiosis I only
meiosis II only
mitosis and meiosis I
mitosis and meiosis II
Which of the following occurs in meiosis but not in mitosis?
chromosome replication
synapsis of chromosomes
alignment of chromosomes at the equator
condensation of chromosomes
Which part of the cell cycle is being shown?
metaphase
telophase
cytokinesis
interphase
Which stage is being shown?
metaphase of mitosis
metaphase 1 of meiosis
metaphase 2 of meiosis
You have isolated DNA from three different cell types of the same organism, determined the relative DNA content for each type, and plotted the results on the graph shown in the figure. Which sample might represent an animal cell in the G2 phase of the cell cycle?
I
II
III
either I or II
Somatic cells of roundworms have four individual chromosomes per cell. How many chromosomes would you expect to find in an ovum from a roundworm?
4
2
8
What is a major difference between mitosis and meiosis I in a diploid organism?
Sister chromatids separate in mitosis, while homologous pairs of chromosomes separate in meiosis I.
Sister chromatids separate in mitosis, while homologous pairs of chromosomes separate in meiosis II.
DNA replication takes place prior to mitosis, but not before meiosis I.
Only meiosis I results in daughter cells that contain identical genetic information
Crossing over normally takes place during which of the following processes?
meiosis II
meiosis I
mitosis
mitosis and meiosis II
Independent assortment of chromosomes is a result of _____.
the random way each pair of homologous chromosomes lines up at the metaphase plate during meiosis I
the random combinations of eggs and sperm during fertilization
the random distribution of the sister chromatids to the two daughter cells during anaphase II
the diverse combination of alleles that may be found within any given chromosome
When homologous chromosomes cross over, what occurs?
Two chromatids get tangled, resulting in one re-sequencing its DNA
Two sister chromatids exchange identical pieces of DNA
Corresponding segments of non-sister chromatids are exchanged
Maternal alleles are "corrected" to be like paternal alleles and vice versa
Imagine that there are twenty-five different species of protists living in a tide pool. Some of these species reproduce both sexually and asexually, and some of them can reproduce only asexually. The pool gradually becomes infested with disease-causing viruses and bacteria. Which species are more likely to thrive in the changing environment?
the sexually reproducing species
the asexually reproducing species
Sexually and asexually reproducing species are equally likely to thrive
What is this diagram showing?
crossing over
independent assortment
interphase
cytokinesis
What is this diagram showing?
independent assortment
interphase
mitosis
random fertilization
