question

In plants and algae, what is a by-product of photosynthesis?

answer

O2

question

In the Calvin cycle, what happens to NADPH?

answer

it is oxidized

question

Which of the following best describes the benefit to early photosynthetic organisms gained by having two different photosystems in one cell?

answer

They could use water as an electron donor

question

In addition to chloroplasts, which of the following organelles of eukaryotic cells is believed to have originated by endosymbiosis?

answer

mitochondria

question

Where does the oxygen come from that is produced as a by-product of photosynthesis?

answer

from breakdown of water

question

Which step of the Calvin cycle would be affected first by a lack of NADPH?

answer

reduction

question

ATP production in photosynthesis requires:

answer

light, electrons, and protons

question

Photorespiration occurs because:

answer

there is more O2 than CO2 in the atmosphere.

question

Which of the following is thought to be the first group of organisms able to use water as an electron donor in photosynthesis?

answer

cyanobacteria

question

Which of the following is true concerning the Calvin cycle and light-harvesting reactions of photosynthesis?

answer

They take place in different compartments of the same organelle.

question

Which of the following is/are rubisco substrates?

answer

CO2, O2, and RuBP

question

Chemicals called uncouplers can make membranes permeable to small molecules and ions. What effect might un-couplers have on photosynthesis?

answer

decreased ATP production because the proton gradient would decrease

question

The occurrence of photorespiration _____ CO2 and _____ ATP.

answer

produces; consumes

question

It is thought that the evolution of two photosystems from one likely involved:

answer

either transfer of genetic material or gene duplication and divergence.

question

A researcher is carrying out an experiment where she labels a protein with a fluorescent tag (so she can visualize its location in a cell), and introduces this tagged protein into the lumen of a single thylakoid. She observes her treated cells periodically, and notices that the labeled protein can move between grana, but is never observed in the stroma. What can she deduce?

answer

The protein likely travels through a common lumen shared by thylakoid membranes and grana, and cannot easily diffuse through the thylakoid membrane.

question

Which of the following correctly describes the role of rubisco in the Calvin cycle?

answer

Rubisco incorporates CO2 from the atmosphere into an organic molecule.

question

Xanthophyll pigments:

answer

prevent formation of reactive oxygen species, reflect yellow light, absorb light energy, convert light energy into heat,

question

All cells able to carry out photosynthesis have:

answer

a plasma membrane.

question

For every six CO2 molecules incorporated into carbohydrate molecules, how many triose phosphates can be exported from the chloroplast?

answer

2

question

Photosystem I is a _____ than photosystem II.

answer

weaker oxidant and a stronger reductant

question

During their experiments with chlorella, Calvin and Benson found no free glucose. Why do you think this is?

answer

Glucose is stored as starch.

question

From its ground state, photosystem II can:

answer

absorb light

question

Many photosynthetic prokaryotes are capable of cyclic electron transport only. It is likely that such organisms can _____ but not _____.

answer

produce ATP; reduce CO2

question

Photosystem II and photosystem I differ in:

answer

H+ production, and electron donors and acceptors.

question

Which of the following is responsible for the transport of electrons between photosystem II and photosystem I?

answer

cytochrome b6f.

question

The Calvin cycle includes 15 enzymes, most of which are involved in:

answer

RuBP regeneration.

question

Which of the following compounds is required for the carboxylation step of the Calvin cycle?

answer

RuBP

question

Cyclic electron transport enhances ATP production because:

answer

electrons are transferred from ferredoxin to plastoquinone.

question

In the Calvin cycle, ATP is required to:

answer

donate a phosphate group to 3-PGA.

question

Signal transduction results in:

answer

a response by the cell.

question

Which of the following statements is not true regarding a neurotransmitter?

answer

Like Delta or Notch, neurotransmitters are usually attached to the cell surface.

question

In the context of cell signaling, to what does the term ligand refer?

answer

a signaling molecule

question

What is the function of adenylyl cyclase?

answer

to form cyclic AMP

question

Signaling through receptor kinases:

answer

takes place in most eukaryotic organisms.

question

Growth factors such as platelet-derived growth factor function in:

answer

paracrine signaling

question

What is the cell's likely response to ligand binding to a steroid receptor located in the nucleus?

answer

a change in gene expression

question

How many subunits make up some types of G protein?

answer

three

question

The first step following PDGF binding of the receptor is:

answer

dimerization.

question

In cell communication, which one of the following is a requirement of the responding cell?

answer

It must have receptor proteins.

question

Cell signaling over a long distance is known as:

answer

endocrine signaling.

question

Which type of protein adds a phosphate group to another molecule?

answer

kinase

question

GTP binding occurs on which subunit of a G protein?

answer

the alpha subunit

question

Cellular responses that result from receptor kinase activation tend to:

answer

involve changes in gene expression.

question

Recall from the text the example of cell communication in Streptococcus pneumoniae: the rate of DNA uptake by pneumococcal cells increases sharply when they are at high density due to changes in gene expression brought about by signaling between cells. If the pneumococcal cells did not express receptor protein, how would the rate of DNA uptake be affected when the cells reach high density?

answer

There would be no change in the rate of DNA uptake.

question

Which of the following signaling molecules would you expect to travel the longest distance in the human body?

answer

testosterone

question

Which one of the following is not a cell surface-type receptor?

answer

steroid receptor

question

Inactivation of a cell-surface receptor depends on:

answer

both the binding affinity of the receptor and concentration of ligand surrounding the cell.

question

Many scientists use chemical inhibitors to interfere with normal signaling pathways within eukaryotic cells. If such inhibitors are large, nonpolar molecules, what is the likely method of action of these chemical inhibitors?

answer

These chemical inhibitors likely bind to receptors and interfere with receptor activation or signal-receptor binding.

question

The signaling molecule involved in contact-dependent cell signaling is:

answer

a transmembrane protein.

question

Which type of cell-surface receptor undergoes changes in phosphorylation in response to binding of its ligand?

answer

receptor kinase

question

Cyclic AMP (cAMP) is an example of a(n):

answer

second messenger.

question

Ras is a type of G protein because it:

answer

is only active when it binds GTP.

question

The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on:

answer

the presence of the appropriate receptors on the cells of the target tissue or organ.

question

What is a growth factor?

answer

a small protein that influences cell growth and division, a signaling molecule involved in paracrine signaling, a soluble molecule that can alter gene expression in a cell

question

What determines the specificity of a receptor protein?

answer

the ligand-binding site

question

Ras is most similar to:

answer

the alpha subunit of three-subunit G proteins.

question

A researcher introduces a signal produced by bacteria to eukaryotic cells that she is culturing in the laboratory. Remarkably, she notices that this signal results in an increase in eukaryotic gene expression. How is this possible?

answer

The signal is either similar in structure to a ligand used by eukaryotes, or this signaling pathway is utilized by both prokaryotes and eukaryotes.

question

Notch and Delta are both transmembrane proteins involved in cell communication in the developing nervous system of vertebrate animals. What makes Notch different from Delta?

answer

Notch is a receptor and Delta is a signaling molecule

question

How does an "activated" receptor transfer information into the cell?

answer

through a conformational change of the receptor

question

In the G protein-coupled signal transduction pathway, phosphatases are responsible for the inactivation of:

answer

the protein target activated by protein kinase A.

question

What is the end-result of activating the MAP kinase pathway?

answer

a change in gene expression

question

Many diseases are the result of a problem with cell signaling. Which of the following diseases best exemplifies this fact?

answer

A specific type of cancer, caused by a truncated receptor that becomes stuck in the activated form.

question

The first event that happens after a signaling molecule binds to a receptor is:

answer

the receptor is activated.

question

Imagine that a researcher is studying the embryonic development of mice that do not express the signal molecule Delta. What will likely be true of these mice?

answer

The mice will have fewer glia compared to their normal counterparts.

question

Which is the correct order for these steps in cell signaling?

answer

receptor activation, signal transduction, response

question

Cell signaling over a long distance is known as:

answer

endocrine signaling

question

Which of the following is not an essential element involved in communication between all cells?

answer

second messenger

question

Growth factors such as platelet-derived growth factor function in:

answer

paracrine signaling.

question

A researcher has discovered a new ligand that can pass through the cell membrane and bind to a receptor in the nucleus. Which of the following statements is not likely true of this ligand?

answer

This ligand likely binds to a transmembrane receptor.

question

In order for a G protein to be active:

answer

the alpha subunit must bind GTP and the beta and gamma subunits must separate from the alpha subunit.

question

What is the end-result of activating the MAP kinase pathway?

answer

a change in gene expression

question

Inactivation of a cell-surface receptor depends on:

answer

both the binding affinity of the receptor and concentration of ligand surrounding the cell.

question

Cell signaling between two nerve cells can be thought of as an example of paracrine signaling because:

answer

the cells are in close proximity.

question

Where would you expect to find the receptor for a nonpolar ligand?

answer

either in the nucleus of the cell or in the cytosol

question

Why are some mutations of Ras associated with cancer?

answer

Ras activates the MAP kinase signal transduction pathway.

question

In many signaling pathways, once a signaling molecule binds to a receptor, the receptor becomes phosphorylated. This initial phosphorylation step best demonstrates:

answer

receptor activation.

question

Signaling molecules involved in paracrine and autocrine signaling:

answer

travel by diffusion.

question

Why don't steroid hormones bind to transmembrane cell-surface receptors?

answer

Steroid hormones are nonpolar and therefore are able to cross the cell's plasma membrane, binding to receptors inside the cell.

question

Which of the following signaling molecules would you expect to travel the longest distance in the human body?

answer

testosterone

question

Which of the following structures are responsible for the shape of a cell?

answer

cytoskeleton

question

Dynamic instability is the rapid assembly and disassembly of:

answer

microtubules.

question

Cadherin is an example of:

answer

a cell adhesion molecule.

question

Which of the following is a component of the extracellular matrix made by a plant cell?

answer

cellulose

question

An epithelial tissue is defined as:

answer

a collection of cells that lines cavities or outside surfaces.

question

Which one of the following cytoskeletal elements is associated with supporting the movement of materials inside the cell?

answer

both microtubules and microfilaments

question

Which of the following cell junctions is involved in creating a barrier between cells?

answer

tight junction

question

The extracellular matrix is composed of:

answer

proteins and polysaccharides

question

Predict what would happen if an embryonic epidermal cell switched from expressing E-cadherin to N-cadherin.

answer

The cell would leave the epidermis and join the neural cells.

question

Which of the following is a component of the extracellular matrix produced by an animal cell?

answer

cellulose

question

A researcher is studying a population of cells that are shaped normally, but appear to slide past one another. This is likely the result of mutations in genes encoding:

answer

components of cell junctions.

question

Which one of the following is not a cellular function associated with microtubules?

answer

muscle contraction

question

The most likely reason(s) a metastatic tumor cell might lose its connection to the basal lamina would be:

answer

the loss of integrin proteins from the cell's surface, or a change in the type of integrin proteins present on the cell's surface.

question

Within the plant cell wall, the primary cell wall contains ______, and the secondary cell wall is composed of ______.

answer

both pectin and cellulose; both lignin and cellulose

question

Which of the following statements about the skin is true?

answer

The epidermis is made up of epithelial tissue whereas the dermis is made up primarily of connective tissue.

question

How do cells connect to the extracellular matrix?

answer

through integrins

question

Which of the following is a specific type of extracellular matrix?

answer

basal lamina

question

The basal lamina is:

answer

a specialized form of the extracellular matrix found beneath all epithelial tissues.

question

Which one of the following is not a cellular function of microfilaments?

answer

flagellar movement

question

The natural loss of dead cells from the surface of your skin is a result of:

answer

both the loss of adherens junctions between epithelial cells, and the breakdown of desmosomes.

question

In nerve cells, the centrosome is located near the nucleus. Vesicles move from near the nucleus to the end of long extensions (axons) along microtubules. Based on these two facts, it is possible to conclude that these vesicles are moving in the _____ direction on the microtubule using the motor protein _____.

answer

plus end; kinesin

question

A researcher is assessing the expression of a certain protein in cells. This protein appears as a "web" in the cytoplasm of cells. The protein is likely:

answer

a component of cytoskeleton

question

Which of the following cytoskeletal elements is capable of assembling and disassembling in the cell?

answer

both microflaments and microtubules

question

Macrophage cells undergo a process called phagocytosis in which material is brought into a cell in the form of membrane vesicles and then transported along microtubules toward the cell center. Assuming that the centrosome is near the cell center, you can predict that these vesicles are moving to the _____ end of microtubules using the motor protein _____.

answer

minus end; dynein

question

The internal cytoskeletal structure of cilia and flagella grows out from a structure called a basal body located near the cell surface. Based on this information, where would you predict the plus end of the microtubules to be located?

answer

near the tip of the cilia or flagella

question

In skin, the cells of the epidermis connect to the basal lamina through cellular junctions known as hemidesmosomes. Select the cytoskeletal element that helps maintain the integrity of this connection.

answer

intermediate filaments

question

Gap junctions and plasmodesmata have what feature in common?

answer

They both allow direct transport of materials between cells.

question

The process of cell division in a prokaryotic cell is called:

answer

binary fission.

question

Which of the following is not a characteristic of meiotic cell division?

answer

Daughter cells are genetically identical.

question

What is a cyclin?

answer

a protein that activates kinases and a protein whose levels change with the cell cycle

question

A phragmoplast functions to:

answer

form a new cell wall.

question

Another name for non-sister chromatids is:

answer

homologous chromosomes.

question

The division of the cell's cytoplasm in a eukaryotic cell is known as:

answer

cytokinesis

question

In which phase of mitosis does the nuclear envelope reform?

answer

telophase

question

What type of protein is being activated by the G1/S cyclin-CDK complex to promote the expression of histone proteins?

answer

a transcription factor

question

A malignant cancer differs from a benign cancer in that:

answer

malignant cancers invade surrounding tissue and benign cancers do not.

question

The division of genetic material in a eukaryotic cell is called:

answer

mitosis.

question

What is the function of the centromere?

answer

to attach the sister chromatids to each other

question

What would happen if crossing over occurred between sister chromatids?

answer

Nothing would happen because sister chromatids are genetically identical or nearly identical.

question

Which one of the following statements regarding the S cyclin-CDK complex is true?

answer

It ensures that DNA is not replicated multiple times.

question

A woman has her genome sequenced and finds that she carries a mutation in p53. Will she develop cancer?

answer

Possibly—this mutation may predispose her to developing certain types of cancer.

question

Replication of DNA in a eukaryote occurs during which phase of the cell cycle?

answer

S phase

question

At the start of mitosis, how many sister chromatids are present in a human cell?

answer

92

question

Homologous chromosomes separate from each other in:

answer

meiosis I.

question

The division of genetic material in a eukaryotic cell is called:

answer

mitosis

question

In which phase of mitosis do spindle microtubules shorten?

answer

anaphase

question

How must spindle microtubules attach to chromosomes during prometaphase of meiosis I?

answer

Spindle microtubules from one pole must attach to both kinetochores in a pair of sister chromatids.

question

In which phase of mitosis do sister chromatids separate?

answer

anaphase

question

Predict what would happen if crossing over between homologous chromosomes occurred as part of mitosis.

answer

Daughter cells would not be genetically identical, and they could contain two copies of the same allele.

question

How do CDKs promote cell division?

answer

They phosphorylate other proteins.

question

What type of gene is c-src (cellular-src)?

answer

proto-oncogene

question

In which phase of mitosis do chromosomes condense?

answer

prophase

question

Replication of DNA in a eukaryote occurs during which phase of the cell cycle?

answer

S phase

question

During what step in meiosis do the daughter cells become haploid?

answer

anaphase I

question

The division of the cell's cytoplasm in a eukaryotic cell is known as:

answer

cytokinesis.

question

In which phase of mitosis does the mitotic spindle form?

answer

prophase

question

During what step in meiosis do the daughter cells become haploid?

answer

anaphase I

question

What protein forms the contractile ring during cytokinesis in animal cells?

answer

actin

question

What is the function of the centromere?

answer

to attach the sister chromatids to each other

question

In which phase of mitosis does the nuclear envelope reform?

answer

telophase

question

Crossing over occurs during which step in meiosis?

answer

prophase I

question

The division of genetic material in a eukaryotic cell is called:

answer

mitosis.

question

Mitotic cell division is considered asexual because:

answer

the daughter cells receive DNA from one parent cell, and the daughter cells are genetically identical.

question

The division of the cell's cytoplasm in a eukaryotic cell is known as:

answer

cytokinesis.

question

A human cell with a total of 23 chromosomes is:

answer

haploid.

question

A cell that is not actively dividing is in what phase of the cell cycle?

answer

G0

question

hey

answer

hi

question

Which DNA sequence is very alike?

answer

a pair of sister chromatids

question

How are sister chromatids held together?

answer

by cohesion

question

Will a mutation acquired by a bacterium very likely be inherited by all daughter cells?

answer

yes

question

What are two external factors that initiate prokaryotic cell division?

answer

nutrient concentration and environmental conditions

question

What are responsible for the dependance hepatocytes on lamin?

answer

integrins

question

What type of cell junction connects to the basal lamina?

answer

hemidesosome

question

CAM is made up of what?

answer

cadherins and integrins

question

What are different types of cell junctions?

answer

adherins, desmosomes, tight junctions

question

Do microfilaments assemble in a "9+2" array?

answer

no microtubules do

question

Do all eukaryotic cells have all three cytoskeleton elements?

answer

no, plants do not have intermediate filaments

question

Which component of cytoskeleton is hollow in the middle?

answer

microtubules

question

What are the three main components of cytoskeleton? (largest to smallest)

answer

microtubules, intermediate filaments, microfilaments

question

Which two components of cytoskeleton are polar?

answer

microtubules and microfilaments

question

Which two components of cytoskelton help with movement?

answer

microtubules and microfilaments

question

What plays a role in cell shape?

answer

the cytoskeleton

question

What are microtubules made up of?

answer

tubulin

question

what are microfilaments up of?

answer

actin

question

What is the initial carbon input in the Calvin cycle?

answer

rubisco

question

What molecule in oxidized in photosynthesis?

answer

water

question

is fluorescence an example of a chemical reaction?

answer

yes

question

photosynthesis

answer

a biochemical process for building carbohydrates using energy from sunlight and CO2 taken from the air

question

What is the photic zone and who deep does it penetrate?

answer

photic zone is the area in the ocean for which photosynthesis can occur which extends from the surface to about 100m deep

question

What type of reaction is photosynthesis?

answer

redox

question

what is reduction?

answer

acquires electrons and gains energy

question

what is oxidation?

answer

loses electrons and releases energy

question

during photosynthesis why are co2 molecules reduced?

answer

to form higher-energy carbohydrate molecules

question

what does photosynthesis require?

answer

input of energy from ATP and the transfer of electrons from an electron donor

question

where does the photosynthetic electron transport chain take place

answer

specialized membranes

question

ATP and NADPH are needed to synthesize carbohydrates using CO2, what is this process called

answer

the calvin cycle

question

where is the photosynthetic electron chain located

answer

thylakoid membrane

question

thylakoid membranes form structures that resemble flattened sacs, groups of flattened sacs are called ______

answer

grana

question

how are grana connected

answer

membrane bridges

question

what is the region surrounding the thylokoid membrane called

answer

stroma

question

single interconnected compartment inside of the thylakoid membrane

answer

lumen

Biology 2170 Exam 3 University of Toledo – Flashcards

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