BYS 300 Final

spectrin

Red blood cells have been very useful in the study of membranes and the protein components that provide structural support. Which of the following proteins is the principal fibrous protein in the cortex of the red blood cell?

Synthesis of proteins ___________

Ribosomes

True

Ribosomes are cytoplasmic structures that, during protein synthesis, become linked by an mRNA molecule to form polyribosomes.

True

Ribosomes are cytoplasmic structures that, during protein synthesis, become linked by an mRNA molecule to form polyribosomes.

False. The outer nuclear membrane is continuous with the ER in all proteins made by ribosomes bound there end up in the ER lumen

Ribosomes bound to the outer nuclear membrane make proteins that are translocated co-translationally into the membrane.

True

Secretory vesicles bud off the trans face of the Golgi.

True

The final electron acceptor in the mitochondrial electron transport chain is oxygen.

Chloroplast

The final electron acceptor is NADP+

Answer: True

The final electron acceptor is oxygen.

False. Acetylcholine is short-lived and exerts its affects locally. Indeed, the consequences of prolonging its lifetime can be disastrous. Compounds that inhibit the enzyme acetylcholinesterase Which normally breaks down acetylcholine a nerve muscle synapse, are extremely toxic: for example, the nerve gas sarin, used in chemical warfare is in acetylcholinesterase inhibitor.

After acetylcholine is secreted from cells, it is long-lived, because it has to reach target cells all over the body.

True

After an electron has been removed by light, the positively charged chlorophyll in the reaction center of the first photosystem (photosystem II) has a greater affinity for electrons than O2 has

How do Wee 1 and Cdc25 regulate the activity of the mitotic CDK?

As soon as the M cyclin-CDK complex is formed, it is phosphorylated at two adjacent sites by the inhibitory protein Wee1. This modification results in an inactive M cyclin-CDK complex. The phosphates are then removed from the activating phosphatase Cdc25, which dephosphorylates the M cyclin-CDK complex, resulting in its active form.

True

Glycolipids move between different membrane-enclosed compartments during their synthesis but remain restricted to one side of the lipid bilayer

True

Glycolysis can occur in the absence of oxygen

Fermentation will occur, rather than proceeding to the TCA cycle. This process occurs to regenerate NAD+.

Glycolysis is considered an anaerobic process where oxygen is not used in the pathway. However, oxygen is necessary for glycolysis to occur. Explain what will happen during this condition (when oxygen is not present). Why?

False (glycolysis will still occur)

Glycolysis will not occur in the absence of oxygen.

False

Green plants have only chlorophyll as the photosynthetic pigment in their leaves.

Where does mitochondrial electron transport chain occur?

Inner Mitochondrial Membrane

Which enzyme can join two ends of DNA together?

ligase

Name the process in which larger molecules are broken down into smaller molecules

catabolism

How many ATP and NADPH are used in the calvin cycle?

9ATP and 6NADPH

False

A cell can live on its own without any messages from its surroundings.

For a reaction A + B→C + D which is at equilibrium, which of the following is true? A. ∆G = 0 B. Keq = 1 C. ∆G > 0 D. ∆G < 0

A. ∆G = 0

What are the similarities and differences between the reactions that lead to the activation of G proteins and the reactions that lead to the activation of Ras?

Activation in both cases depends on proteins that catalyze GDP-GTP exchange on the G protein or Ras protein. Whereas activated GPCRs perform this function directly for G proteins, enzyme-linked receptors assemble multiple signaling proteins into a signaling complex when the receptors are activated by phosphorylation; one of these is an adaptor protein that recruits a guanine nucleotide exchange factor that fulfills this function for Ras.

False

All eukaryotic cells take 24 hours to complete the cell cycle.

True

All transport vesicles in the cell must have a v-SNARE protein in their membrane.

False

An action potential can move in both directions

True

Because it requires the removal of four electrons to release one O2 molecule from two H2O molecules, the water-splitting enzyme in photosystem II has to keep the reaction intermediates tightly bound so as to prevent partly reduced, and therefore hazardous, superoxide radicals from escaping.

True

Chloroplast's electron transport chain has one pump only

True

Both the concentration gradient and the membrane potential affect the passive transport of charged solutes

Which of these proteins is not found in the nucleosome core? A. H3 B. H2A C. H1 D. H4

C. H1

Which of the following organelles has three membranes? A. lysosome B. nucleus C. chloroplasts D. mitochondria

C. chloroplasts

In eukaryotes translation occurs in the _________ and transcription occurs in the ________. A. nucleus, cytosol B. nucleus, nucleus C. cytosol, nucleus D. nucleolus, cytosol

C. cytosol, nucleus

Energetically favorable reactions A. are not possible B. have a Keq < 1 C. have a negative ∆G D. create order in the universe

C. have a negative ∆G

Which type of eukaryotic RNA is synthesized by RNA Polymerase I? A. tRNA B. hnRNA C. rRNA D. micro RNA

C. rRNA

Lactate

During anaerobic metabolism in muscle cells pyruvate is converted to

True

During glycolysis there is a net production of 2 ATP

True

During glycolysis, there is a net production of 2 ATPs.

False (unsaturation will decrease)

During high temperatures, unsaturation increases.

Both mitochondria and chloroplasts

Electron transfer leads to establishment of a proton gradient

What organelle is directly attached to the nucleus?

Endoplasmic reticulum

Site of addition of lipids and carbohydrates to proteins being secreted ________________

Golgi Apparatus

1. A: Extrinsic apoptosis stimulated by cell-surface receptor 2. A: Intrinsic apoptosis stimulated by p53 3. A: Necrosis

Read and indicate if the following statements undergo necrosis, extrinsic apoptosis, or intrinsic apoptosis. Describe what initiates both extrinsic and intrinsic apoptotic pathways. 1. A viral-infected cell recognized by phagocytic cells. 2. The DNA of a skin cell is damaged by UV light. 3. The buildup of reactive oxygen intermediates within a somatic cell leading to cell lysis.

False

In prokaryotes the TCA cycle occurs in the mitochondria

False

In prokaryotes, the electron transport chain involves the mitochondrial membrane.

False (ethanol)

In yeast cells, lactate is produced during anaerobic conditions

Adaptin

The protein that determines which cargo proteins will be transported in a specific vesicle is

Answer: True

The proton-motive force consists of membrane potential and pH.

T or F: ∆G is different from ∆G˚

True

Plus, minus, plus

Tubulin add to the ______ end of microtubules and fall off of the _______ end of the microtubules. However, actin filaments add to and dissociate from the _______ end.

False

Twelve ATP molecules are produced from one acetyl-CoA during the TCA cycle

True

Tyrosine phosphorylation serves to build binding sites for other proteins to bind to RTKs.

True

Ubiquinone and cyctochrome c are both diffusable electron carriers

Answer: False (Ubiquinone or Cytochrome Q is an electron carrier not a protein)

Ubiquinone is a protein embedded in the membrane.

Mitochondria

Water is produced as a result of electron transfer.

In the endoplasmic reticulum

Where does most new membrane synthesis take place in a eukaryotic cell?

from sunlight

Where does the energy for photosynthesis come from?

True

Most enzyme-linked receptors have turned out to be tyrosine kinases.

Answer: True

NADH produces more ATP than FADH2.

False (NADH has more energy)

NADH yields less energy than FADH2

What process can form larger molecules from smaller molecules?

anabolism

Which of the following modifications are not known to occur to histone proteins? A. acetylation B. methylation C. phosphorylation D. sulfonylation

D. sulfonylation

T or F: The ∆G of a spontaneous reaction is always >0.

False

False

Fermentation only occurs during anaerobic conditions to regenerate FADH2

False (Lateral movement is spontaneous)

Flip-Flop movement of phospholipids is spontaneous

False. Two cars bending,

GTP is hydrolyzed by tubulin to cause the bending of flagella.

What organelle has 3 membranes?

chloroplast

Name the organelle that metabolizes reactive oxygen species:

peroxisomes

Surrounds the cytoplasm ____________ __________

plasma membrane

False (low pH)

High proton concentration means high pH

Where does light-independent stage occur in the cell?

Stroma

Seven Characteristics of Life

1. Highly organized 2. Maintain Homeostasis 3. Ability to reproduce 4. Growth and development 5. Metabolize energy 6. Respond to stimuli 7. Adapt to their environment

Alpha helix and beta sheet are types of __________ structures of _________. A. secondary, proteins B. tertiary, proteins C. secondary, nucleic acids D. primary, proteins

A. secondary, proteins

Answer: 20 ATP 6 NADH * 2.5 ATP = 15 ATP 2 FADH2 * 1.5 ATP = 3 ATP 2 ATP Total: 15 ATP + 3 ATP + 2 ATP = 20 ATP

2 NADH and 2 ATP are produced during Glycolysis and 2 NADH are produced from pyruvate oxidation to acetyl-CoA. However, the citric acid cycle produces 6 NADH, 2FADH2, and 2ATP. How many ATP are produced? (Hint: NADH = 2.5 ATP and FADH2 = 1.5 ATP)

Amphipathic

A molecule that has both a hydrophilic portion and a hydrophobic portion is said to be

Diagram and describe the process by which proteins are transported from the cytosol into the nucleus.

A protein containing a nuclear localization signal is recognized by a cytosolic import receptor. The import receptor and the signal sequence on the protein bind. The import receptor associates with the cytosolic fibrils and the protein and receptor move into the nucleus through a nuclear pore. Once in the nucleus, the protein and the signal sequence dissociate from the import receptor by the binding of Ran-GTP to the import receptor. The protein and the signal sequence stay in the nucleus while the import receptor and Ran-GTP exit the nucleus and enter the cytosol. Once in the cytosol, the Ran-GTP is hydrolyzed to become Ran-GDP which will then dissociate from the import receptor. The import receptor is now ready to recognize more proteins destined for the nucleus.

Diagram and describe the process by which proteins are transported from the cytosol into the nucleus. (Part 2)

A protein containing a nuclear localization signal is recognized by a cytosolic import receptor. The import receptor and the signal sequence on the protein bind. The import receptor associates with the cytosolic fibrils and the protein and receptor move into the nucleus through a nuclear pore. Once in the nucleus, the protein and the signal sequence dissociate from the import receptor by the binding of Ran-GTP to the import receptor. The protein and the signal sequence stay in the nucleus while the import receptor and Ran-GTP exit the nucleus and enter the cytosol. Once in the cytosol, the Ran-GTP is hydrolyzed to become Ran-GDP which will then dissociate from the import receptor. The import receptor is now ready to recognize more proteins destined for the nucleus.

Topoisomerase

A researcher testing plant products as potential new therapeutics notes that molecule X induces cultured human cells to arrest within the S phase of the cell cycle. Which of the following is the most likely target of molecule X?

a membrane protein

A start-stop sequence is found in a protein that will be

False

A symport would function as an antiport if its orientation in the membrane were reversed (i.e., if the portion of the molecule normally exposed to the cytosol faced the outside of the cell instead)

By definition, prokaryotic cells do not possess __________. A. nucleus B. ribosomes C. DNA D. RNA

A. nucelus

The structure consisting of histone proteins with DNA wrapped around them is a A. nucleosome B. nucleolus C. nucleus D. nuclear membrane

A. nucleosome

Non-coding sequences at the ends of eukaryotic chromosomes are called A. telomeres B. exons C. introns D. origins of replication

A. telomeres

True

Actin filaments can add new monomers to either the plus end or the minus end.

True

Actin protein monomers associate with each other non-covalently to form actin filaments.

False

All of the energy produced is in the form of heat

Na+

All of the following can diffuse through the cell membrane except

Cl-

All of the following can diffuse through the cell membrane except:

False

All proteins in the membrane can freely diffuse

True. Otherwise they could not dock at the correct target membrane or recruit a fusion complex to a docking site.

All transport vesicles in the cell must have a v-SNARE protein in their membrane.

False

Although cholesterol is a hydrophobic molecule, it has a hydrophillic head group like all other membrane lipids.

A ligand gated channel

An ion channel that is opened by binding of a signal molecule to it is called

Ligand-gated channel

An ion channel that opens and closes based on the binding of a hormone to it is called a

False

Decreasing the percentage of unsaturated fatty acids in a biological membrane will increase its fluidity.

The transmembrane proton gradient is used to drive ATP synthesis

Define chemiosomotic coupling.

During translation, each animo-acyl tRNA binds in which site on the ribosome? A. P B. A C. E D. stop codon

B. A

Which of the following types of bonds is a covalent bond between cysteine amino acids? A. hydrogen bonds B. disulfide bonds C. ionic bonds D. hydrophobic forces

B. disulfide bonds

The 3' to 5' exonuclease activity of DNA Polymerase III is used to A. fill gaps B. proofread DNA synthesis C. remove primers D. synthesize the DNA

B. proofread DNA synthesis

In prokaryotes the role of the sigma factor is A. recognize the start codon for translation B. recognize the promoter for transcription C. help DNA polymerase bind to the origin of replication D. be a termination factor for translation

B. recognize the promoter for transcription

Answer: False (NADH donates electrons to complex I)

Both NADH and FADH2 donate electrons to complex I (NADH Dehydrogenase)

False (transporters are not gated)

Both channels and transporters are selective and gated.

True

Both chlorophyll and heme contain an extensive system of double bonds that allows them to absorb visible light

False

Both chloroplasts and mitochondria have three membranes

True. Nucleotide free Beta-gamma complexes can activate ion channels, GTP-bound alpha subunits can activate enzymes. The GDP-bound form of trimeric G proteins is the inactive state.

Both the GTP-bound alpha subunits and nucleotide-free beta gamma complexes--but not GDP-bound, fully assembled G proteins--can activate other molecules downstream of GPCRs.

True

Both the GTP-bound α subunits and nucleotide-free ẞɣ complexes—but not GDP-bound, fully assembled G proteins—can activate other molecules downstream of GPCRs.

Answer: True

During the presence of uncoupling agents, the energy stored in proton is released as heat.

Which of the following types of microscopy employs a light microscope and requires that samples be fixed and stained in order to reveal cellular details?

Bright field

False

Calmodulin regulates the intracellular Ca 2+ concentration.

False. Calmodulin senses but does not regulate intracellular Ca2+ levels

Calmodulin regulates the intracellular Ca2+ concentration.

True

Carbon dioxide is produced during the Krebs' cycle

True

Cells expend energy in the form of ATP hydrolysis so as to maintain ion concentrations that differ from those found outside the cell.

H+ symporter

Cells make use of H+ electrochemical gradients in many ways. Which of the following proton transporters is used to regulate pH in animal cells?

True

Certain H+ pumps are fueled by light energy

False

Channels have specific binding pockets for the solute molecules they allow to pass

What makes a good model organism?

Cheap, easy to grow, and easy to genetically manipulate

True

Complex 2 of the electron transport chain accepts the electrons from FADH2

Answer: False (Complex II is the only complex that is not a pump)

Complex II or Succinate Dehydrogenase is a proton pump.

False (2 is not a proton pump)

Complexes I, II, III are proton pumps

Answer: False (Complexes I, III, and IV are transmembrane proteins, while Complex II is a peripheral protein)

Complexes II, III, and I are transmembrane proteins.

ATP; GTP

Cyclic AMP is derived from _________________, while cyclic GMP is derived from ________________.

How does cyclic AMP become AMP?

Cyclic AMP is formed from ATP by using the enzyme adenylyl cyclase to remove two phosphate groups from ATP and join the remaining phosphate to the sugar part of the AMP molecule. Once cyclic AMP is formed, it can be degraded by the enzyme cyclic AMP phosphodiesterase which adds water to the compound, breaking the bond between the phosphate and the sugar, thereby creating AMP.

False

Cyclic phosphodiesterase converts cyclic AMP back to ATP.

Muscle contraction Amoeboid movements of phagocytic cells Formation of the cleavage furrow following telophase of mitosis

Cytochalasin D inhibits the formation of microfilaments. Which of the following biological activities will be hindered?

Answer: False (Cytochrome c receives electrons from complex III and donates the electrons to complex IV. Complex IV will donate electrons to oxygen)

Cytochrome c is a soluble protein that receives electrons from complex II and donates electrons directly to oxygen.

False

Cytochrome c is embedded in the membrane.

True

Cytochromes have heme with Fe to accept and donate electrons

Answer: 10 ATP Products of TCA cycle: 1 FADH2, 1 GTP, 3 NADH 3 NADH * 2.5 ATP = 7.5 ATP 1 FADH2 = 1.5 ATP 1 GTP = 1 ATP Total = 7.5 ATP + 1.5 ATP + 1 ATP = 10 ATP

How many ATP are produced from one acetyl-CoA?

Name the sequence known as the Central Dogma

DNA transcribes to RNA translates to Proteins

True

Hydrogen bonds that form between lipid head groups and water molecules are continually broken and re-formed

Contact dependent

Delta binding to the Notch receptor is a type of __________ signaling.

Microtubules: Figure in book Intermediate filaments: Figure in book Actin filaments: Figure in book

Describe the formation mechanism of microtubules, intermediate filaments, and actin filaments.

True

Different signals originating from the plasma membrane can be integrated by cross-talk between different signaling pathways inside the cell.

True

During the light-dependent reactions of photosynthesis the pH in the thylakoid lumen decreases

True

During the presence of uncoupling agents, oxygen consumption occurs but ATP production is inhibited

Answer: True

During the presence of uncoupling agents, oxygen consumption occurs but ATP production is inhibited.

GTP

Dynamic instability in microtubules is driven by the hydrolysis of

Mutations that inhibit the activity of p53

Each of the following events is likely to trigger cell apoptosis, except:

False

In eukaryotes, all membrane-enclosed organelles are surrounded by one lipid bilayer

True

Electrons are donated to the molecule with the highest reduction potential.

A chemical reaction is defined as spontaneous if there is a net loss of free energy during the reaction process. However, spontaneous reactions do not always occur rapidly. Favorable biological reaction required ___________ to selectively speed up reactions and meet the demands of the cell.

Enzymes

False

Equal solutes concentration on both sides of the membrane generates a positive potential. (Hint: V = 62/z * log(Cout/Cin)

We see light that bounces off of objects (reflected light). Chlorophyll is best at trapping and absorbing the red - orange wavelengths of light and the blue, indigo, and violet wavelengths of light. It is not good at absorbing the green wavelengths. The green light is reflected, so it is the part we see. Therefore, chlorophyll looks green to us.

Explain why chlorophyll appears green to us in terms of what happens to different wavelengths of light that strike a chlorophyll molecule.

False

FAD+ reduction to FADH2 occurs during pyruvate oxidation

T or F: All amino acids are hydrophobic.

False

T or F: All amino acids have more than one codon.

False

T or F: DNA Polymerase adds nucleotides in the 5' to 3' direction on one strand and in the 3' to 5' direction on the other.

False

T or F: Histones have large numbers of negatively charged amino acids.

False

T or F: Ribosomes must wait for transcription to finish before it can start translating an mRNA molecule

False

T or F: TEM and SEM illuminate the specimen using a beam of light.

False

True

Fifteen ATP molecules are produced from 6 NADH

Answer: False (intermembrane space)

High proton concentration is established in the matrix.

False (intermembrane space and thylakoid space)

High proton concentration is established in the mitochondrial matrix and chloroplast's stroma.

It is stored as starch.

How can cells store the sugar that is produced in photosynthesis?

As soon as the M cyclin-CDK complex is formed, it is phosphorylated at two adjacent sites by the inhibitory protein Wee1. This modification results in an inactive M cyclin- CDK complex. The phosphates are then removed from the activating phosphatase Cdc25, which dephosphorylates the M cyclin-CDK complex, resulting in its active form.

How do Wee 1 and Cdc25 regulate the activity of the mitotic cdk?

Use Figures in book. You will not have to describe this in detail on your exam, but you may have a question that asks about a specific segment of this mechanism.

How do muscles contract? Describe this mechanism in detail.

Cyclic AMP is formed from ATP by using the enzyme adenylyl cyclase to remove two phosphate groups from ATP and join the remaining phosphate to the sugar part of the AMP molecule. Once cyclic AMP is formed, it can be degraded by the enzyme cyclic AMP phosphodiesterase which adds water to the compound, breaking the bond between the phosphate and the sugar, thereby creating AMP.

How does cyclic AMP become AMP?

As wavelength increases, amount of energy decreases. Thus, violet light (which has a shorter wavelength) has more energy that red light (which has a longer wavelength).

How does the amount of energy in light change as the wavelength increases?

It is the reverse of the overall reaction for cellular respiration.

How does this compare to the overall reaction for cellular respiration?

False

Hydrophobic portions of molecules interact well with water molecules

True

IP 3 is produced directly by cleavage of an inositol phospholipid without incorporation of an additional phosphate group.

True. The inositol phospholipid that is cleaved to produce IP3 contains three phosphate groups, one of which links the sugar to the diacylglycerol live bed. IP3 is generated by a simple hydrolysis reaction

IP3 is produced directly by cleavage of an inositol phospholipid without incorporation of an additional phsophate group.

True. Lysosomal proteins are selected in the trans Golgi network and packaged into transport vesicles that deliver them to the late endosomes. If not selected, they would enter by default into transport vesicles that move constitutively to the cell surface.

If the delivery of prospective lysosomal proteins from the trans Golgi network to the late endosomes were blocked, lysosomal proteins would be secreted by the constitutive secretion pathways shown in Figure 15-30.

K+; Na+ and Cl-

In a typical mammalian cell, _______ is (are) higher on the inside, and _________ is (are) higher on the outside.

Na+ and Cl-; K+

In a typical mammalian cell, _________ is (are) higher on the outside, and __________ is (are) higher on the on the inside

False

In animal cells DNA is copied during the G 1 phase of the cell cycle.

True

In cells, the reaction takes place in more than one step

NADH

In the Citric Acid Cycle, 3 of which of the following are produced?

True

Kinase is responsible for phosphorylation

True

In the electron transport chain, electrons are transferred from NADH with a low reduction potential to oxygen with a high reduction potential.

in the chloroplasts

In what organelle of a plant cell does photosynthesis take place?

Removal of heart muscle cells damaged by oxygen depletion following cardiac infarction

In which of the following situations would cells die by necrosis, not apoptosis?

The light reactions take place in the thylakoids. The Calvin cycle takes place in the stroma.

In which part of the chloroplast does each stage occur?

True

Increasing the percentage of unsaturated fatty acids in a biological membrane will increase its fluidity.

Plectin

Intermediate filaments provide a great deal of strength to cells in epithelial sheets due to being crosslinked by the protein

What are the specific roles of kinesin and dynein in the cell and what provides energy for them?

Kinesin and dynein are motor proteins that move cargo (vesicles and organelles) to specific places in the cell. For example, kinesin moves towards the positive end of a microtubules while dynein moves toward the negative end of a microtubule. For kinesin and dynein to move, ATP hydrolysis must occur on their globular heads. How this movement occurs: ATP hydrolysis causes a globular head to release from the microtubule and move the head forward. This continual ATP hydrolysis is responsible for the movement, release, and binding of the globular head to the microtubule

True. A continual outward movement of ER is required; in the absence of microtubules, the ER collapses toward the center of the sale.

Kinesin moves ER membranes along microtubules so tgat the network of ER tubules becomes wretched throughout the cell.

Plus end; minus end

Kinesins move toward the __________ of a microtubule, while dyneins move toward the __________ of a microtubule.

True. Both extensions are associated with transmembrane proteins that protrude from the plasma membrane and enable the cell to form new anchor points on the substratum.

Lamellipodia and filopodia are "feelers" that a cell extends to find anchor points on the substratum that it will then crawl over

True

Lipids in a lipid bilayer do not flip-flop readily from one lipid monolayer to the other

True

Lipids in a lipid bilayer rapidly exchange positions with one another in their own monolayer

True

Lipids in a lipid bilayer spin rapidly around their long axis

Contains degradative enzymes to digest proteins ______________

Lysosome

False. Lysosomes also digest internal organelles by autophagy

Lysosomes digest only substances that have been taken up by cells by endocytosis.

False

Many steps in the oxidation of sugar molecules involve reaction with oxygen gas

True

Many, but not all, electron-transfer reactions involve metal ions

True

Margarine contains more saturated lipids than the vegetable oil form which it is made

True

Margarine contains more saturated lipids than the vegetable oil from which it is made

Answer: False (Matrix has high pH because of low proton concentration, while intermembrane space has low pH because of high proton concentration)

Measuring the pH of both matrix and intermembrane space indicated that the matrix has low pH and intermembrane space has high pH.

False

Membrane lipids frequently flip-flop between one monolayer and the other

False

Membrane phospholipids often flip-flop across the membrane

Detergent

Membrane proteins, unlike cytosolic proteins, are more difficult to purify. Which of the following substances is most commonly used to help purify a membrane protein?

False

Metabolic reactions that help synthesize all cellular components is catabolism

Oxidative metabolism for ATP production ____________________

Mitochondria

...

Mitochondrial ETC

Where does pyruvate oxidation occur in the cell?

Mitochondrial Matrix

False

Most of the dry weight of a tree comes from the minerals that are taken up by the roots

False. Mitochondria do not participate in vesicular transport, and therefore N-linked glycoproteins Which are exclusively assembled in the ER, cannot be transported to mitochondria

N-linked sugar chains are found on glycoproteins that face the cell-surface, as well as glycoproteins that face the lumen of the ER, trans Golgi network, and mitochondria

False (NAD+ is oxidized form)

NAD+ is the reduced form of NADH

Answer: False (NADH produces 2.5 ATP and FADH2 produces 1.5 ATP)

NADH produces 1.5 ATP, while FADH2 produces 2.5 ATP.

False

NADPH is found in plants only.

False (NADH is catabolic, NADPH is anabolic)

NADPH is used in catabolic reactions, while NADH is used in anabolic reactions.

Guanylyl cyclase

Nitric oxide is a vasodilator, which functions in activating __________________.

False

None of the produced energy is in the form of heat

Mitochondria

One source of electrons is NADH

True

Oxygen is known as the final electron acceptor in the electron transport chain

Chloroplast

Oxygen is produced as a result of electron transfer

False

Paracrine signaling molecules travel in the blood stream to their target organs.

True

Protein kinase A can stimulate both downstream enzymes and transcription regulators.

True

Phospholipids have different polar head groups attached to them.

True

Phosphorylation of glycogen phosphorylase activates it.

Light Dependent and Light Independent

Photosynthesis consists of two stages including:

True

Photosynthesis is the light-driven transfer of an electron from chlorophyll to a second molecule that normally has a much lower affinity for electrons

False (they do not pump protons)

Photosystems I and II are proton pumps

Plants use Carbon dioxide, which we expell, and produce oxygen, which we take in.

Plants are important for our survival. Explain.

False

Plants have chloroplasts and therefore can live without mitochondria

False (photosystem 2)

Plastoquinone transfers electrons from photosystem I to a proton pump called cytochrome b-f6 complex.

Compare and contrast protein transport into the ER and into the nucleus. List at least two major differences in the mechanisms and speculate why the ER mechanism might not work for nuclear import and vice versa.

Proteins are imported into the nucleus after they have been synthesized, folded, and, if appropriate, assembled into complexes. In contrast, unfolded polypeptide chains are translocated into the ER as they are being made by the ribosomes. Ribosomes are assembled in the nucleus yet function in the cytosol, and the enzyme complexes that catalyze RNA transcription and splicing are assembled in the cytosol yet function in the nucleus. Thus, both ribosomes and these enzyme complexes need to be transported through the nuclear pores intact. Nuclear pores are gates, which are always open to small molecules; in contrast, translocation channels in the ER membrane are normally closed, and open only after the ribosome has attached to the membrane and the translocating polypeptide chain has sealed the channel from the cytosol. It is important that the ER membrane remain impermeable to small molecules during the translocation process, as the ER is a major store for calcium in the cell, and calcium release into the cytosol must be tightly controlled. Nuclear localization signals are not cleaved off after protein import into the nucleus; in contrast, ER signal peptides are usually cleaved off. Nuclear localization signals are needed to repeatedly re-import nuclear proteins after they have been released into the cytosol during mitosis, when the nuclear envelope breaks down.

Ribosomes

Proteins are synthesized by

True

Proteins are transported into the nucleus in their completely folded conformation.

Both mitochondria and chloroplasts

Proton flow through a transmembrane protein results in the phosphorylation of ADP

Answer: True

Proton pumping through the inner membrane produces an electrochemical gradient, which is responsible for ATP production.

False (carry out active transport)

Pumps carry out passive transport.

True

Pyruvate is the final product of glycolysis.

Growth and development

RTKs are examples of enzyme-coupled receptors. Therefore, RTKs can regulate _______.

0 mV

What would be the resting potential across an artificial membrane if all charged molecules on both sides were equally permeable?

True

Reduction potential is the measure of electron affinities.

Which of the following types of microscopy requires the specimen be placed in a vacuum?

Scanning Electron or Transmission Electron

Which of the following types of microscopy requires coating the sample with a thin layer of a heavy metal to produce three-dimensional images of the surface of the sample?

Scanning electron

What structural feature of proteins directs them to the correct cellular compartment?

Signal sequence: a continuous stretch of an amino acid sequence on a protein, typically 15-60 amino acids long, that specifies the destination of the protein. If a protein does not have a signal sequence, then the protein will remain in the cytosol.

False

Steroid hormones bind to receptors on the cell surface only.

False (antiport)

Sodium-potassium pump is an example of a symport pump

True

Some cells that grow in the absence of O2 produce CO2

True

Some membrane proteins are enzymes

True

Some organisms carry out the reverse reaction

Microtubule function

Taxol and Vinblastine are anticancer drugs that interfere with chromosome separation in dividing cells. These drugs then most likely affect

True

The Calvin Cycle uses 9 ATP directly in the synthesis of the one 3C sugar phosphate

MAP kinase kinase kinase activates MAP kinase kinase by phosphorylation (Converting ATP to ADP and P). Once MAP kinase kinase is activated, it activates MAP kinase by the same mechanism. MAP kinase then phosphorylates various effector proteins, sending the signal downstream to either change protein activity or change gene expression.

The activation of Ras further transmits a signal by activating MAP kinase kinase kinase. Which enzyme does MAP kinase kinase kinase activate, how does it activate this enzyme, and it turn, what does this enzyme do?

True

The alpha subunit of a G protein stimulates downstream enzymes, while the beta-gamma complex of a G protein stimulates ion channels.

False. The single sequences that direct proteins to the ER contain a core of eight or more hydrophobic amino acids. The sequence shown here contains many hydrophilic amino acid side chains, including the charged amino acids His, Arg, Asp, , and, The uncharged hydrophilic amino acids

The amino acid sequence Leu-His-Arg-Leu-Asp-Ala-Gln-Ser-Lys-Leu-Ser-Ser is a signal sequence that directs proteins to the ER.

False

The amount of cyclin-dependent kinases goes up and down through the various phases of the cell cycle.

True

The antenna complex has many chlorophyll molecules that are responsible for capturing light energy and converting light energy to chemical energy.

Plectin

The budding of coated vesicles from eukaryotic plasma membrane fragments was observed in a mixture of clathrin, dynamin, adaptin, plectin, and GTP. Which of these could be eliminated without affecting the vesicle budding process?

On the extracellular face

The carbohydrate portion of glycolipids is found in membranes

Actin

The cell cortex just under the plasma membrane is made of

True

The electrochemical gradient determines the direction of solute flow.

True

The electrochemical proton gradient consists of two components: a pH difference and an electrical potential

Answer: True

The electron transport chain in animal cells has three pumps.

False

The electron-transport chain generates an electrical potential across the membrane because it moves electrons from the intermembrane space into the matrix

pyruvate

The end product of glycolysis

Pyruvate

The end product of glycolysis is

True

The energy is produced by a process that involves the oxidation of carbon atoms

False

The energy of ATP synthesis comes from proton pumping

True

The energy of pumping protons comes from electron transfer

Answer: True

The energy released by electron transportation is reserved in proton pumping.

True

The extracellular signal molecule acetylcholine has different effects on different cell types in an animal and often binds to different cell-surface receptor molecules on different cell types.

True. Acetylcholine, for example, slows the beating heart muscle cells by binding to a GPCR, and stimulates the contraction of skeletal muscle cells by binding to a different acetylcholine receptor, which is an ion channel coupled receptor

The extracellular signal molecule acetylcholine has different effects on different cell types in an animal amd often binds to different cell-surface receptor molecules on different cell types.

By phosphorylating glucose, glucose will then be trapped inside the cell, forcing it to undergo glycolysis rather than being expelled throughout the body for other needs. This phosphorylation also aids in the production of ATP and facilitates enzyme binding and specificity.

What is the goal of glucose phosphorylation?

Kinase

The general name for an enzyme that transfers phosphate groups from ATP to a protein is:

Pyruvate Dehydrogenase Complex

What is the name of the complex responsible for pyruvate oxidation?

True

The inactivation of sodium channels is responsible for action potential propagation in one direction.

False (becomes positive)

The inside of the cell becomes negative during an action potential.

True

The low cytosolic Ca2+ concentration sensitizes the cell to an influx of Ca2+, ensuring a rapid response to environment stimuli.

False

The membrane potential of an axon temporarily becomes more negative when an action potential excites it.

Phospholipids

The most abundant type of molecule that makes up the cell membrane is

facilitated diffusion

The movement of a molecule across a membrane, down its concentration gradient, through a transport protein is called

False (spontaneous)

The movement of electrons from low to high reduction potentials is a nonspontaneous process.

Answer: True

The movement of electrons is coupled to the pumping of protons.

True

The movement of ions toward their concentration gradient has a positive delta G

True

The number and location of mitochondria within a cell can change, depending on both the cell type and the amount of energy required.

Rubisco

What is the name of the enzyme that catalyzes the first step of the light-independent stage?

False

The only non-protein portion of the electron transport chain is cytochrome c

Both mitochondria and chloroplasts

The organelle contains cytochromes and iron-sulfur proteins in its electron transport chain

Both mitochondria and chloroplasts

The organelle requires a system of intact membranes to generate ATP

Answer: 122 ATP 1 acetyl-CoA = 10 ATP (from previous question) 9 acetyl-CoA = 90 ATP 8 NADH * 2.5 ATP = 20 ATP 8 FADH2 * 1.5 ATP = 12 ATP Total: 90 ATP + 20 ATP + 12 ATP = 122 ATP

The oxidation of 18-carbon fatty acid yields 9 acetyl-CoA, 8 NADH, and 8 FADH2. How many ATP are produced from the 18-carbon fatty acid? (Hint: Acetyl-CoA goes through the citric acid cycle)

False

The plasma membrane is highly impenetrable to all charged molecules

True

The plasma membrane of many animal cells contains open K+ channels, yet the K+ concentration in the cytosol is much higher than outside the cell

False

The plus ends of microtubules grow faster because they have a larger GTP cap.

True

The principle site of intracellular degradation is the lysosome.

Clathrin

The protein responsible for forming the spherical structure of endocytic vesicles from the plasma membrane is

Caspases

The proteins that ultimately result in apoptosis of cells are

False

The reaction supplies the cell with essential water

False

The role of chlorophyll in photosynthesis is equivalent to that of heme in mitochondrial electron transport

True

The source of electrons for photosynthetic electron transport is H2O

False (water)

The source of electrons in chloroplast's electron transport chain is NADPH

False (also FADH2)

The source of electrons in the mitochondrial electron transport chain is NADH only

Answer: True

The sources of electrons are NADH and FADH2.

True

The sugar layer that surrounds all cells makes cells more slippery

False (located on extracellular side)

The sugars of glycoproteins are located in the intracellular side

Explain how electron transport in both mitochondria and chloroplast help ATP synthesis?

The transport of electron is coupled to the pumping of protons, which provides ATP synthase the energy it needs to produce ATP

True

The transverse tubules in muscle cells are an extension of the plasma membrane, with which they are continuous; similarly, the sarcoplasmic reticulum is an extension of the endoplasmic reticulum.

True

The ẞɣ subunits of trimeric G proteins can activate phospholipase C.

Microfilaments - myosin Microtubules - kinesin and dynein Intermediate filaments have no motor proteins because they lack polarity, which is present in both microfilaments and microtubules. Instead, the ends of intermediate filaments are chemically modified.

There are different motor proteins that move on microfilaments and microtubules. Name the motor proteins that move on both microfilaments and microtubules. Explain why intermediate filaments lack motor proteins.

a) Association with the appropriate cyclin b) Presence of an activating phosphorylation c) Removal of an inhibitory phosphorylation

What is the necessary condition or set of conditions for full activity of the M-phase CDK? (Note: There are multiple answers.)

6 CO2 + 6 H2O 🡪 glucose (C6H12O6) + 6 O2

What is the overall reaction for photosynthesis?

Produce activated carriers (NADH and FADH2)

What is the purpose of the citric acid cycle?

Produce activated carriers (ATP and NADPH)

What is the purpose of the light-dependent stage?

T or F: The highest resolution of microscopy is obtained using the electron microscope.

True

T or F: The nucleolus is where many of the genes for rRNA are located.

True

T or F: Transmembrane proteins generally have alpha-helix regions that span the lipid bilayer.

True

True

Two NADH are produced during pyruvate oxidation

To generate NAD+ from NADH so glycolysis can continue under anaerobic conditions, glycolysis is the only way to produce ATP

What is the purpose of the production of ethanol by yeast under anaerobic condition?

True

Three ATP molecules are produced from 2 FADH2.

Which type of microscopy has the ability to resolve cellular components as small as 2 nm?

Transmission electron

True

Transport vesicles deliver proteins and lipids to the cell surface.

False

Transporters allow solutes to cross a membrane at much faster rates than do channels

False

Transporters are similar to channels, except that they are larger, allowing folded proteins as well as smaller organic molecules to pass through them.

False (Channels have higher rate than transporters)

Transporters have a higher rate of transport that channels do.

T or F: A cell's genome is its complete set of DNA

True

T or F: Antibodies are Y-shaped

True

T or F: Confocal microscopy is a type of fluorescent microscopy.

True

T or F: Eukaryotic cells are in general bigger than prokaryotic cells.

True

T or F: Kinase can add a phosphate group to molecules

True

T or F: Methylation is one modification of histone proteins that can change gene expression.

True

T or F: New cells only arise from and division of existing cells.

True

T or F: Plant cells have a cell wall that animals lack.

True

Answer: False (Ubiquinone accepts electrons from complex I)

Ubiquinone accepts electrons from both complex I and complex II.

Answer: True

Ubiquinone is hydrophobic.

True

Ubiquinone is the only non-protein component in the electron transport chain.

False (donates them to complex 3)

Ubiquinone receives electrons from both NADH and FADH2 and donates the electrons to complex II

True

Unsaturation maintains membrane fluidity

oxygen gas (O2)

What photosynthesis waste product is formed in the light reactions?

chlorophyll a, chlorophyll b, and carotenoids

What plant pigments are involved in photosynthesis?

1) Contact-dependent and Autocrine 2) Neuronal 3) Paracrine 4) Endocrine

What are the five types of signaling mechanisms? Describe or diagram each signaling mechanism. Rank the signaling mechanisms from 1 to 4, where 1 is the signaling mechanism that travels the shortest distance and 4 is the signaling mechanism that travels the largest distance.

2NADH + 2H+ + 2pyruvate + 2ATP

What are the products of glycolysis?

2 pyrvate→2 acetyl-CoA + 2CO2 + 2NADH + 2H+

What are the products of pyruvate oxidation?

Per 1: 3NADH + 3H+ + 2CO2 + 1FADH2 + 1GTP Per 2: 6NADH + 6H+ + 4CO2 + 2FADH2 + 2GTP

What are the products of the citirc acid cycle (per one acetyl-CoA + per two acetyl-CoA)?

Amino acids, Steroids, and Proteins

What are the three different classes of hormones? Give examples of each along with their origin and action.

light reactions and Calvin cycle

What are the two stages of photosynthesis?

Replacement of GDP with GTP

What event would activate a G protein?

Pyruvate is then shuttled to the mitocondrial matrix where it is converted to acetyl-CoA

What happens after the production of pyruvate under aerobic conditions.

In the Calvin cycle, carbon dioxide molecules (CO2) are combined with each other and with the electrons and H's from NADPH to form glucose (C6H12O6).

What happens to carbon dioxide molecules in the Calvin cycle reactions?

Water molecules (H2O) are split to give electrons, H+ ions, and oxygen gas (O2) .

What happens to water molecules in the light reactions?

Protein kinase B; cell growth and survival

What is another name for Akt and what is Akt responsible for?

Substrate-level phosphorylation is the process of producing ATP by removing a phosphate from a substarate molecule and adding it to ADP. Oxidative phosphorylation is the production of ATP from oxidized NADH and FADH2. Photophosphorylation is the phosphorylation of ADP to form ATP using the energy derived from sunlight.

What is the difference between substrate-level phosphorylation, oxidative phosphorylation, and photophosphorylation (light-depenedent stage of photosynthesis)?

3×ribulose 1,5-bisphosphate + 3×CO2→6×3-phosphoglycerate

What is the first step of the light-independent stage?

ATP and NADPH

What two products of the light reactions are used up in the Calvin cycle?

A small monomeric GTPase switch protein

What type of protein is Ras?

False

When a cell enters G 0 it is permanently removed from the cell cycle.

False

When activated by binding of a signal molecule to a GPCR, the associated G-protein exchanges the bound GTP for GDP.

Synaptic

When glutamate functions as a neurotransmitter the kind of signaling it does is

Mitochondrial Matrix

Where does citric acid cycle occur in the cell?

Cytosol

Where does glycolysis occur in the cell?

Thylakoid Membrane

Where does light-dependent stage occur in the cell?

Intermediate filament protein

Which class of cytoskeletal proteins regulates the disassembly of the nuclear envelope during mitosis?

Chlorophyll looks green to us because most of the green wavelengths are reflected rather than being absorbed. For this reason, green light is not an effective color of light to power photosynthesis. Chlorophyll a and b together absorb light most effectively in the blue to violet range and the orange to red range. Since violet wavelengths have the most energy in the visible light range (due to their shorter wavelengths) they can provide the maximum energy for photosynthesis

Which colors of light are most effective for photosynthesis? Explain why.

cytochrome c oxidase

Which components of the electron-transport chain is required to combine the pair of electrons with molecular oxygen?

Enzyme-coupled receptor

Which coupled receptor does insulin use?

anaerobically growing yeast

Which of the following cells rely exclusively on glycolysis to supply then with ATP?

Mitochondria

Which of the following cellular organelles is involved in the initiation of the intrinsic pathway of apoptosis?

A. The cell's DNA is damaged. B. The cell is lacking nutrients

Which of the following conditions could prevent a skin cell from passing the G1 checkpoint? (Note: There are multiple answers.)

Opening of Ca2+ channels in the ER

Which of the following is a result of increased IP3 in the cell?

IP3

Which of the following is a secondary messenger derived from a membrane phospholipid?

Triglycerides

Which of the following is not a component of cell membranes?

Cholesterol

Which of the following membrane lipids does not contain a fatty acid tail?

Intermediate filaments and mitosis

Which of the following pairs is incorrect?

Ran

Which of the following proteins is NOT part of the synthesis of proteins that are intended for the ER lumen?

Diacylglycerol

Which of the following second messengers remain bound to the plasma membrane

For molecules that have a strong tendency to pass along their electrons, the standard redox potential is negative.

Which of the following statements about "redox potential" is true?

All the proteins in a membrane are anchored to the cell cortex so that they can't move

Which of the following statements about membranes is NOT true:

It results, in part, from the concentration gradients for Na+ and K+

Which of the following statements about the resting membrane potential is TRUE?

Synaptic response changes in magnitude depending on frequency of stimulation.

Which of the following statements best reflects the nature of the synaptic plasticity?

Estrogen

Which of the following would have an intracellular receptor?

Adaptin

Which of these proteins is NOT a GTPase?

A. Water-soluble hormones bind to cell-surface receptors, while water-insoluble hormones bind to either cytosolic or nuclear receptors. B. Water-soluble hormones are associated with secondary messengers, while water- insoluble hormones are associated with gene expression.

Which statement is true regarding both water-soluble and water-insoluble hormones?

True. Actin is needed to make the contractile ring that causes the physical cleavage between the two daughter cells, whereas the mitotic spindle that partitions the chromosomes is composed of microtubules.

Without actin, cells can form a functional mitotic spindle and pull their chromosomes apart but cannot divide

1. Cyclic AMP concentration will decrease because the alpha subunit is inactivated; therefore, adenylyl cyclase is inactivated. 2. Cyclic AMP concentration will decrease because alpha subunit is unable to dissociate from Beta-gamma complex; therefore, adenylyl cyclase is inactivated. 3. Cyclic AMP concentration will increase because alpha subunit remains active during GTP binding; therefore, adenylyl cyclase remains active.

You are studying the effects of various mutations in a β-adrenergic receptor (G-protein coupled receptor). The intracellular concentration of cyclic AMP increases when epinephrine is bound to the β-adrenergic receptor. How will the mutations listed below affect cyclic AMP concentration? Explain your answers. 1. A mutation in the alpha subunit of a G protein that inhibits nucleotide exchange: 2. A mutation in the beta subunit of a G protein that increases its affinity to the alpha subunit in its GTP bound state: 3. A mutation in the alpha subunit of a G protein that prevents GTP hydrolysis:

uptake of calcium

cyclic GMP cause vasodilation of blood vessels by ____________.

Enzymes ________ the activation energy for a specific reaction.

decrease

Feedback inhibition involves down-regulating enzyme activity by the accumulation of a product ________ in the pathway.

earlier

Name the organelle that degrades cell components and other molecules brought to into the cell:

lysosome

The reduction of a molecule can sometimes result in the acquisition of a proton, a reaction referred to as ______________.

protonation or hydrogenation