Biology 121 Chapter 9 Questions, BIOL 410 Exam 2
During osmosis, water moves from a region of ______ to a region of ______. Please choose the correct answer from the following choices, and then select the submit answer button. high solvent concentration; low solvent concentration high solute concentration; low solute concentration "high solvent concentration; low solvent concentration" AND "low solute concentration; high solute concentration" are both correct answers. low solute concentration; high solute concentration
"high solvent concentration; low solvent concentration" AND "low solute concentration; high solute concentration" are both correct answers.
The __ end of the microtubule is near the plasma membrane while the __ end is near the MTOC.
+ ; -
Dynein always travels from _____ while kinesin travels from ________.
+ to - ; - to +
Glycolysis: •The number of reactions involved •Where it occurs in the cell •The reactants and products of the three phases •The net products per glucose molecule at the end of phase 3.
-10 reactions -occurs in cytoplasm -Prep phase: reactants 2 ATP; products fructose-1, 6-biphosphate -Cleavage Phase: Reactants, 6-C glucose; Products: 2 3-C GAP's -Payoff phase: Reactants: 1 GAP 1 glucose; Products: 3 NADH and 4 ATP Net payoff: 1 glucose makes 6 ATP
What chlorophyll does with light energy
-Releases the energy as heat and some fluorescence when isolated -Transfers energy to a neighboring chlorophyll when clustered -Energy is transferred until it reaches a reaction center
difference between substrate-level phosphorylation and oxidative phosphorylation in the production of ATP
-Substrate-level phosphorylation: coupled chemical reactions that produce ATP -Oxidative phosphorylation: an electrochemical gradient drives the formation of ATP
Pyruvate oxidation: •Where it occurs in the cell. •The products produced per pyruvate in this step. •The net products produced per glucose molecule at the end of this step.
-in mitochondrial matrix -(Pyruvate -> CO2 and Acetyl group; acetyl group -> Coenzyme a = acetyl Co-A; NAD+ -> NADH) Pyruvate products: CO2, 1 NADH, 1 acetyl-CoA Glucose Products: 2 CO2, 4 NADH, 2 ATP, 2 Acetyl-CoA
structure of mitochondria
-inner and outer membrane -intermembrane space between them -mitochondrial matrix inside of inner member
How FRAP shows that peripheral and integral membrane proteins move fluidly with lipid bilayers
-proteins labeled with green fluorescent protein (GFP) -laser bleaches spot on membrane that is nonfluorescent -spot begins to fill with fluorescence again over time, showing that the still fluorescent proteins are able to move into the bleached area -proves fluid mosaic with mixture of molecule types
The reactions of photorespiration
-rubisco adds O2 to RuBP instead of CO2 resulting in formation of 3-C 3-PGA and 2-C molecule (2-phosphoglycolate) -2-phosphoglycolate cant be used by Calvin cycle, so 2 are used to form 1 3-PGA and CO2 -1 ATP is used
organelles that make up the endomembrane system
1. Nuclear envelope, 2. endoplasmic reticulum, 3. Golgi apparatus, 4. lysosome, and 5. plasma membrane
Match the different types of endocytosis to the correct description. 1.Tiny, invaginations of small molecules. Happens at random 2.endocytosis of lipid rafts 3.Proteins in the shape of a triskelion coat the vesicle and pulls membrane into cell 4.Engulfing a bacteria by moving part of the plasma membrane out.
1. Pinocytosis 2. cavelion mediated endocytosis 3. clatherin receptor mediated endocytosis 4.phagocytosis
three steps of the Calvin cycle
1. carboxylation 2. reduction 3. regeneration
How photorespiration consumes plant energy
1. consumes ATP from cellular respiration 2. Carbons that had been reduced using energy in Calvin cycle are oxidized and lost lost
Rank the membrane permeability of molecules based on polarity.
1. hydrophobic molecules 2. small uncharged polar molecules 3. large uncharged polar molecules 4. ions
Which of the following is NOT responsible for amplifying the signal in a cell responding to adrenaline signaling? 1.) One adrenaline molecule can bind to and activate many receptors simultaneously. 2.) One activated receptor can activate many G proteins. 3.) One molecule of protein kinase A can phosphorylate and activate many target proteins. 4.) One molecule of adenylyl cyclase can produce many molecules of cAMP.
1.) One adrenaline molecule can bind to and activate many receptors simultaneously.
A protein on a cell surface that binds to a signaling molecule is an example of which of the following elements of cellular communication? 1.) a receptor protein 2.) a signaling cell 3.) a responding cell 4.) a signaling molecule 5.) None of the above
1.) a receptor protein
Second messengers: 1.)All of these choices are correct. 2.)amplify the effects of the signal. 3.)are small intracellular molecules that participate in signal transduction. 4.)are removed in order to terminate a cellular signaling response. 5.)play a role in activation of intracellular signal transduction.
1.)All of these choices are correct.
How many membranes make up a chloroplast? Please choose the correct answer from the following choices, and then select the submit answer button. 1 2 3 5
3
Platelet-derived growth factor (PDGF) is a signaling molecule that functions in which of the following types of cell signaling? 1.) paracrine 2.) autocrine 3.) contact-dependent 4.) endocrine 5.) All of the above
4.) endocrine
range of the electromagnetic spectrum that plants absorb
400-700 nm (aka visible light spectrum w/ least absorbance of green)
Which of the following is TRUE about the Delta protein? 1.) Delta is a transmembrane protein found in embryonic brain cells. 2.) Delta directly signals to a Notch transmembrane protein in adjacent cells. 3.) Delta directs adjacent cells to differentiate into glial cells. 4.) Delta is produced by embryonic stem cells as they differentiate into neurons in the brain. 5.) All of these choices are correct.
5.) All of these choices are correct.
Types of steroids include: 1.)lipid-soluble hormones derived from cholesterol. 2.)insect molting hormones. 3.)glucocorticoids that regulate blood glucose levels. 4.)sex hormones such as estrogen and testosterone. 5.)All of these choices are correct.
5.)All of these choices are correct.
How many times must the cycle be performed to export one triose phosphate?
6
Order the events in clathrin receptor mediated endocytosis in the correct order 1) Clathrin coating builds and vesicle is pulled into the cell 8) Ligand binds to receptor
8, 2, 4, 7, 1, 3, 5, 6
Order the events in clathrin-receptor mediated endocytosis in the correct order 1) Clathrin coating builds and vesicle is pulled into the cell. 2) Receptor changes shape and internalized domain can be accessed. 3) Dynamin pinches off vesicle using GTP. 4) Adaptin binds to the internalization domain. 5) Clathrin coated vesicle is free in cytoplasm. 6) Clathrin is uncoaded by auxillin and Hsp70. 7) Adaptin links to clathrin. 8) Ligand binds to receptor.
8, 2, 4, 7, 1, 3, 5, 6
percentage of sun energy lost during photosynthesis
96% or 8%
Match each description below with the type of cell junction it characterizes:
A band-like attachment where cadherins attach to microfilaments inside the cell and to the extracellular domain of an adjacent cell's cadherin proteins on the outside of the cells. Correct E. adherens junction Correct E. adherens junction A button-like point of attachment where cadherins attach to intermediate filaments inside the cell and to the extracellular domain of an adjacent cell's cadherin proteins on the outside of the cells. Correct D. desmosome Correct D. desmosome A button-like point of attachment where integrins attach to intermediate filaments inside the cell and to a protein of the extracellular matrix on the outside of the cells. Correct C. hemidesmosome Correct C. hemidesmosome A mesh-like attachment between cells formed by binding of transmembrane proteins of one cell to the same protein type on the adjacent cell, preventing substances from passing between cells. Correct B. tight junction Correct B. tight junction Transmembrane proteins on the plasma membrane arranged in a ring that bind to a similar protein ring on an adjacent cell to allow transfer of materials between the cells. Correct A. gap junction Correct A. gap junction
adherens junction
A beltlike junctional complex composed of cadherins that attaches a band of actin to the plasma membrane
desmosome
A button like point of adhesion that holds the plasma membranes of adjacent cells together
cadherins
A calcium-dependent adherence protein, important in the adhesion of cells to other cells
vacuole
A cell structure that absorbs water and contributes to turgor pressure
cell adhesion molecules
A cell-surface protein that attaches cells to one another and to the extracellular matrix
endomembrane system
A cellular system that includes the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, lysosomes, the plasma membrane, and the vesicles that move between them
tissue
A collection of cells that work together to perform a specific function
centrosome
A compact structure that is the microtubule organizing center for animal celles
nucleus
A compartment of the cell that houses DNA in chromosomes
ribosomes
A complex structure of RNA and protein, bound to the cytosolic face of the RER in the cytoplasm, on which proteins are sythesized
cell wall
A defining boundary in many organism, external to the cell membrane, that helps maintain the shape and internal composition of the cell
electrochemical gradient
A gradient that combines that charge gradient and the chemical gradient of protons and other ions
tight junctions
A junctional complex that establishes a seal between cells so that the only way a substance can travel from one side of a sheet of epithelial cells to the other is by moving through the cells by a cellular transport mechanisms
anchors
A membrane protein that attaches to other proteins and helps to maintain cell structure
extracellular matrix
A meshwork of proteins and polysaccharides outside the cell; the main constituent of connective tissue
fluid mosaic model
A model that proposes that the lipid bilayer i s a fluid structure that allows molecules to move laterally within the membrane and is a mosaic of two types of molecules, lipids and proteins
receptors
A molecule on cell membranes that detects critical features of the environment. Receptors detecting signals that easily cross the cell membrane are sometimes found in the cytoplasm
myosin
A motor protein found in muscle cells that carries cargo to the plus end of of microfilaments; used by both striated and smooth muscles to contract and generate force
dynein
A motor protein that carries cargo away from the plasma membrane toward the minus end of the microtubules
kinesin
A motor protein, similar in structure to myosin, that transports cargo toward the plus end of microtubules
intermediate filaments
A polymer of proteins, which vary according to cell type, that combine to from strong, cable-like filaments that provide animal cells with mechanical strength
aquaporins
A protein channel that allows water to flow through the plasma membrane more readily by facilitated diffusion
actin
A protein subunit that makes up microfilaments; used by both striated and smooth muscles to contract and generate force
enzymes
A protein that functions as a catalyst to accelerate the rate of a chemical reaction; enzymes are critical in determining which chemical reactions will take place in a cell
integral membrane proteins
A protein that is permanently associated with the cell membrane and cannot be separated from the membrane experimentally without destroying the membrane itself
peripheral membrane protein
A protein that is temporarily associated with the lipid bilayer or with integral membrane proteins through weak non-covalent interactions
Which of the following is NOT a part of the MAP kinase pathway?
A pyrophosphatase enzyme terminates the cellular response
cellular junctions
A region of the plasma membrane, consisting of cell adhesion molecules and other cytosolic proteins, where a cell makes contact with and adheres to another cell or the extracellular matrix
motor proteins
A small accessory protein that causes muscle contraction by moving the actin microfilaments inside muscle cells
vesicles
A small membrane-enclosed sac that transports substances within the cell
basal lamina
A specialized form of extracellular matrix that underlies and supports all epithelial tissues
micelles
A spherical structure in which lipids with bulky heads and a single hydrophobic tail are packed
pili
A threadlike, hollow structure through which plasmids are transferred between bacteria
integrins
A transmebrane protein, present on the surface of virtually every animal cell, that enables cells to adhere to the extracellular matrix
carrier
A transporter that facilitates movement of molecules
channel
A transporter with a passage that allows the movement of molecules through it
bilayer
A two-layered structure of the cell membrane with hydrophilic "heads" point outward toward the aqueous environment and hydrophobic "tails oriented inward, away from water
epithelial tissue
A type of animal tissue, made up of epithelial cells, that covers the outside of the body and lines many internal structures
contractile vacole
A type of cellular compartment that takes up excess water and waste products from inside the cell and expels them into the external environment
gap junctions
A type of connection between the plasma membranes of adjacent animal cells that permits materials to pass directly from the cytoplasm of one cell to the cytoplasm of another
hemidesmosome
A type of desmosome in which integrins are the prominent cell adhesion molecules
connective tissure
A type of tissue characterized by a few cels and substantial amounts of extracellular matrix; a major component of the dermis
lysosomes
A vesicle derived from the Golgi apparatus that contains enzymes that break down macromolecules such as proteins, nucleic acids, lipids, and complex carbohydrates
How does material move from one cisternae of a Golgi to the next?
A, C, and D are all correct
Anabolism vs. catabolsim
A-B-C-D Anabolism-Build Catabolism-Down •Catabolic reactions have a net -ΔG, -ΔH, +ΔS -anabolic reactions have a net +ΔG, +ΔH, -ΔS
Match the description to the correct type endoplasmic reticulum (ER) cell signaling found near the Golgi where secretory proteins are built where new phospholipid synthesis occurs
A. cortical ER B. trans ER C. rough ER D. smooth ER
signal sequences
AN amino acid sequence that directs a protein to its proper cellular compartment
secondary active transport
Active transport that uses energy of an electrochemical gradient to drive the movement of molecules
primary active transport
Active transport that uses the energy of ATP directly
What happens when the signal recognition particle (SRP) binds to the ribosome after a few amino acids are translated into a growing peptide chain?
All choices listed
Which of the following is a component of plant cell walls
All of the above
Which of the following comparisons between gap junctions and plasmodesmata is NOT true?
All of the above statements are true.
A cell's particular shape is largely determined by: cytosolic proteins that assemble into structures called cell junctions. a mesh of proteins and polysaccharides in the extracellular matrix. All of these choices are correct. cytoskeletal protein networks in the cytoplasm.
All of thee choices are correct
If two signaling pathways are activated simultaneously: they may inhibit each other. All of these choices are correct. they may strengthen each other. one may inhibit the other.
All of these choices are correct
Microtubules increase in length: more quickly at one end than the other. by growing outward from the centrosome. All of these choices are correct. if free tubulin dimers are available. in cycles, following rapid depolymerization.
All of these choices are correct
A cellular response to a signal can be terminated by:
All of these choices are correct.
Cell shapes are largely determined by
All of these choices are correct.
Epithelial tissue is found:
All of these choices are correct.
How is a micelle different from a liposome? Please choose the correct answer from the following choices, and then select the submit answer button. A micelle is composed of a single layer of phospholipids. Micelle phospholipids have bulky head groups. Micelle phospholipids have a single fatty acid tail. All of these choices are correct.
All of these choices are correct.
What factors are required for net movement of a substance to occur by facilitated diffusion? Please choose the correct answer from the following choices, and then select the submit answer button. All of these choices are correct. a transport protein a plasma membrane a concentration gradient
All of these choices are correct.
Which of the following is part of the endomembrane system of a eukaryotic cell? Please choose the correct answer from the following choices, and then select the submit answer button. the Golgi apparatus vesicles All of these choices are correct. nuclear envelope
All of these choices are correct.
Which of the following types of cellular activities can be a response to cell signaling? 1.)Cell signals are released to communicate with other cells. 2.)Cell division is triggered. 3.)Gene expression patterns are changed. 4.)All of these choices are correct. 5.)Enzyme activities are changed
All of these choices are correct.
A researcher is evaluating the role of a growth factor during embryonic development. She notices that this factor functions in both neural development and limb development. How is that possible? The effects of the growth factor may be concentration-dependent. The effects of the growth factor may be dependent on location. The growth factor may result in the transcription of different genes depending on cell type. The growth factor may be signaling through different transduction pathways. All of these choices are possible explanations for the observations.
All of these choices are possible explanations for the observations
Protein sorting:
All proteins begin translation in the cytoplasm after the mRNA is actively transported out of the nucleus through a nuclear pore. The presence or absence of a peptide signal will determine where the protein will go next.
A lipid which is both water-loving and water-hating is
Amphipathic
signal-recognition particle (SRP)
An RNA-protein complex that binds with part of the polypeptide chain and marks the molecule for incorporation into the endoplasmic reticulum (eukaryotes) or the plasma membrane (prokaryotes)
cholesterol
An amphipathic lipid that is a major component of animal cell membranes
liposomes
An enclosed bilayer structure spontaneously formed by phospholipids in environments with neutral pH, like water
Why does active transport require ATP? Please choose the correct answer from the following choices, and then select the submit answer button. An input of energy is needed to allow the movement of molecules from an area of low concentration to one of higher concentration. An input of energy is needed to both speed up the rate of facilitated diffusion and maintain the conformation of transport proteins. An input of energy is needed to maintain the conformation of transport proteins. An input of energy is needed to speed up the rate of facilitated diffusion.
An input of energy is needed to allow the movement of molecules from an area of low concentration to one of higher concentration.
chloroplasts
An organelle that converts energy of sunlight into chemical energy by synthesizing simple sugars
organelles
Any one of several compartments in eukaryotes that divid the cell contents into smaller spaces specialized for different functions
Which of the following statements about G proteins associated with G-protein-coupled receptors is false?
Associated G proteins become active by replacing GTP with GDP
Which of following statements about G proteins associated with G-protein-coupled receptors is false?
Associated G proteins become active by replacing GTP with GDP.
Why is rubisco slow and has to be produced in large amounts in plants.
Bc it is highly specific for CO2 over O2 therefore making it slow (Only 3 per second compared to tens of thousands) so need a lot more of them
How are steroid hormone receptors and cell-surfaced receptors similar?
Both types undergo a conformational change when they bind to their ligand
How are steroid hormone receptors and cell-surface receptors similar?
Both types undergo a conformational change when they bind to their ligand.
Which of the following molecules would most likely require a transport protein to cross the plasma membrane of a red blood cell?
C6H12O6
How is a carrier protein different from a channel protein? Please choose the correct answer from the following choices, and then select the submit answer button. Carrier proteins use ATP, but channel proteins do not. Transport through carrier proteins depends on concentration gradients, but transport through channel proteins does not. Transport through a carrier does not depend on the random motion of molecules. Carrier proteins undergo conformational change so that they are open alternately to one side of the membrane or the other.
Carrier proteins undergo conformational change so that they are open alternately to one side of the membrane or the other.
Prokaryotes absorb their nutrients from the environment; however, prokaryotes also have cell walls. What can you conclude from these statements? Please choose the correct answer from the following choices, and then select the submit answer button. Cell walls are permeable, allowing nutrients to pass through. Prokaryotes live in a hypertonic environment. Osmosis drives the movement of nutrients through the cell wall. Prokaryotic cell walls do not allow nutrients to pass through them.
Cell walls are permeable, allowing nutrients to pass through.
What is a key difference between cell signaling by a cell-surface receptor and cell signaling by an intracellular receptor?
Cell-surface receptors bind polar signaling molecules; intracellular receptors bind nonpolar signaling molecules.
Which of the following statements about "excitable membranes" is correct? (Select all correct choices.)
Cells spend a significant amount of energy to pump Na+ out of muscle cells at rest. Acetylcholine released from a nerve cell binds to a ligand-gated ion channel at the plasma membrane of a muscle cell. The difference in charge across a plasma membrane is called a membrane potential
Membrane bound flattened sacs are _________.
Cicsernae?
Order the progression of vesicles through the Golgi from beginning to end.
Cis to Medial to Trans
difference between competitive and uncompetitive inhibition
Competitive inhibition: an inhibitor binds to the active site and prevents substrate from binding (excessive substrate can overcome) Uncompetitive inhibition: an inhibitor binds to a location other than the active site and prevents the enzyme reaction from occurring (excessive substrate can't overcome)
plasmodesmata
Connections in plant cells between the plasma membranes of adjacent cells that permit materials to pass directly from the cytoplasm of one cell to the cytoplasm of another
How reactive oxygen species (ROS) are created and how plants neutralize or prevent them
Created when NADP+ in short supply so light energy (or in light associated electron) is transferred to O2...Low NADP+ happens when cell isn't doing extensive cell resp. --------- Plants neutralize w/ antioxidants and prevent with yellow-orange accessory pigments
dynamic instability
Cycles of shrinkage and growth in microtubules
Which of the following statements is true regarding cytosol? Please choose the correct answer from the following choices, and then select the submit answer button. Cytosol is the "jelly" substance within cells and it excludes organelles. Cytosol is the "jelly" substance within cells. Cytosol excludes organelles. Cytosol contains, and includes, organelles. Cytosol includes the nucleus.
Cytosol is the "jelly" substance within cells and it excludes organelles.
fluid
Describes lipids that are able to move in the plane of the cell membrane
selective barrier
Describes the plasma membrane, which lets some molecules in and out freely, lets others in and out only under certain conditions, and prevents other molecules from passing through at all
facilitated diffusion
Diffusion through a membrane protein, bypassing the lipid bilayer
The first step following PDGF binding of the receptor is: activation of MAP kinase. activation of gene expression. dimerization. phosphorylation.
Dimerization
tubulin
Dimers ( composed of an a tubulin and a b tubulin) that assemble into microfilaments
Which molecular motor would most likely be involved in carrying endocytosed vesicles?
Dynein
What defines an allosteric effector/allosteric enzyme
Enzymes that change shape when a molecule binds somewhere other than the active site
Composition of all membranes in the cell are exactly the same.
False
Humans are multicellular and have legs to move, thus we do not have cilia in our bodies.
False
The cellulose synthase complex polymerizes cellulose into glucose.
False
The individual proteins in lipid rafts can easily diffuse from place to place by leaving the lipid raft.
False
The inside membrane of the plasma membrane targeted vesicle is the same as the inside of the plasma membrane
False
The lumen of the ER is a closed system and not connected to the perinuclear space.
False
True of False: Given that most ligands form covalent bonds with their associated receptors, these complexes are more or less permanent and can only be broken through the hydrolysis of ATP.
False
Which organelle separates the different hydrolases from other kinds of proteins so that they eventually end up in specific lysosomes?
Golgi
which of the substances would be an example of a peripheral membrane protein associated with the plasma membrane of a cell? -the epidermal growth factor receptor, which binds to signals outside the cell and phosphorylates proteins in the inside of the cell -Grb2, a protein that binds to the intracellular domain of the epidermal growth factor receptor when it is activated -MEK, an enzyme that activates other proteins in the cytoplasm -Myc, a transcription factor that binds to DNA and activates transcription of specific genes
Grb2, a protein that binds to the intracellular domain of the epidermal growth factor receptor when it is activated
Match the scientist to their contribution to the Cell Theory.
Helped dispel the myth of spontaneous generation along with Pasteur. - Virchow All organisms are made of at least one cell.- Schliden and schwan All cells have or have had a nucleus or its equivalent.-brown Cells come from preexisting cells- Pasteur and Virchow All organisms are made of cells and the smalest unit of life.
plasmids
In bacteria, a small circular molecule of DNA carrying a small number of genes that can replicate independently of the bacterial genomic DNA
cytoskeleton
In eukaryotes, an internal protein scaffold that helps cells to maintain their shape and serves as a network of tracks for the movement of substances within cells
cytoskelton
In eukaryotes, an internal protein scaffold that helps cells to maintain their shape and serves as a network of tracks for the movement of substances within cells
lumen
In eukaryotes, the continuous interior of the endoplasmic reticulum; in plants, a fluid-filled compartment enclosed by the thylakoid membrane; generally, the interior of any tubelike structure
epidermis
In mammals, the outer layer of skin, which serves as a water-resistant, protective barrier. In plants, sheets of cells that line the leaf's upper and lower surfaces and constitute the outer cell layer of roots. Also, the outer layer of the cnidarian body
nucleoid
In prokaryotes, a cell structure with multiple loops formed from supercoils of DNA
When the vesicle fuses with the destination membrane, ____ and ____ are excluded from the fusion spot.
Integral proteins; water
What does a ligand-gated channel do? It binds small, nonpolar signaling molecules. It triggers the activity of a phosphatase. It allows ions to move across the plasma membrane. It activates a G protein.
It allows ions to move across the plasma membrane
When an enzyme tags a protein with ubiquitin, what happens to the tagged protein?
It is degraded by the proteasome
How is the energy stored in a molecule of ATP used by the sodium-potassium pump? Please choose the correct answer from the following choices, and then select the submit answer button. It is used to alter the conformation of the pump protein. It is used to transport potassium ions out of the cell. It is used to transport sodium ions into the cell. All of these choices are correct.
It is used to alter the conformation of the pump protein.
Many mutations in receptor kinases that lead to cancer allow the dimerization and activation of the receptor, even in the absence of signaling molecule. An example of this is a mutant form of the EGF receptor kinase called Her2/neu. An antibody that prevents dimerization of Her2/neu receptor kinases is being tested for its effectiveness in stopping cancer. At which stage would this drug work?
It would prevent the receptor from becoming activated.
How do plant cells maintain turgor pressure against the cell wall
Keep water in their vacuoles
structure of the chloroplast
Key features: thylakoid membrane, grana, lumen, and stroma
Which enzyme used ATP to add an inorganic phosphate (PQ4) to a substrate?
Kinase
Which type of protein adds a phosphate group to another molecule? kinase G protein phosphorylase phosphatase
Kinase
Which molecular motor would most likely be involved in vesicle transport from the Golgi to the plasma membrane?
Kinesin
conditions, reactants, and products of both lactic acid and ethanol fermentation
Lactic Acid: -Conditions: when oxygen not available in animals and bacteria -Reactants: NADH -Products: Lactic acid and regenerated NAD+ Ethanol: -Conditions: no oxygen in plants and fungi Reactants: NADH and pyruvate (-> CO2 -> acetaldehyde) Products: Ethanol and NAD+
order of electron flow through the photosynthetic electron transport chain (PETC)
Light -> PS-II (remove water electrons to produce O2 and H+ in lumen) ->Cyt (to pump protons into lumen) this proton accumulation creates gradient that diffuses through ATP synthase producing ATP
Which of the following statements is not true regarding a neurotransmitter?
Like Delta or Notch, neurotransmitters are usually attached to the cell surface.
Which of the following is NOT true of lipid rafts in the plasma membrane?
Lipid rafts are areas of rapid lipid diffusion/movement.
definition of lipid rafts
Lipid rafts are specialized membrane domains enriched in certain lipids, cholesterol, and proteins.
Inside the flattened sacs of the Golgi is the ______.
Lumen
transporters
Membrane proteins that move ions or other molecules across the cell membrane
What are NOT in endomembrane system?
Mitochondria, chloroplasts, and the cytoskeleton are not part of the endomembrane system
amphipathic
Molecules with both hydrophilic and hydrophobic reagions
what are the oxidized and reduced forms of the electron carriers NADH and FADH2
NAD+ and NADH FAD and FADH2
Imagine a cell that has a membrane composed mostly of lipids with saturated fatty acid tails, and that this membrane also has low cholesterol content. What are the characteristics of this cell membrane? Please choose the correct answer from the following choices, and then select the submit answer button. The lipids would be able to easily transition between the inner and outer layers of the bilayer constituting the cell membrane. The lipids contained in such a membrane would be highly mobile, and in near constant flux. Due to its cholesterol content, the cell membrane would remain fluid even at cold temperatures. The characteristics of this cell membrane will closely mirror those of a membrane composed of only unsaturated fatty acids. None of the other answer options is correct.
None of the other answer options is correct.
Which part of a cholesterol molecule is polar?
OH group
nuclear pores
One of the main protein channels in the nuclear envelope that acts as gateways that allow molecules to move into and out of the nucleus and are thus essential for the nucleus to communicate with the rest of the cell
flagella
Organelles that propel the movement s of cells or substances within cells; longer than cilium
direction of electron movement in oxidation and reduction
Oxidation is the loss of electrons and reduction is the gain of electrons LEO says GER
What are the key allosteric controls of cellular respiration.
PFK-1: -when ADP and AMP levels are high they bind to PFK-1 and activate it which stimulates glycolysis -when ATP or citrate is high it binds and inhibits it slowing glycolysis
The electron donor and acceptor for the reaction centers in photosystems II and I
PS-II: Water donates, plastoquinone (Pq) accepts PS-I: Cyt (cytochrome b6f complex) donates and plastocyanin (Pc) accepts
Growth factors such as platelet-derived growth factor function in: autocrine signaling. contact-dependent signaling. endocrine signaling. paracrine signaling.
Paracrine Signaling
A researcher is using a modified version of FRAP. She has devised a technique that allows her to label all the peripheral membrane proteins with a fluorescent tag, and has bleached a specific area of the cell membrane. After 24 hours, she notices that fluorescence has returned to the bleached area. What can she deduce from this experiment? Please choose the correct answer from the following choices, and then select the submit answer button. Peripheral membrane proteins are akin to integral membrane proteins. Peripheral membrane proteins can move freely within the cell membrane. Peripheral membrane proteins may not be permanently associated with the cell membrane. Peripheral membrane proteins can both move freely within the cell membrane and are akin to integral membrane proteins. Peripheral membrane proteins—like transmembrane proteins—are located within the cell membrane.
Peripheral membrane proteins can move freely within the cell membrane.
How do mitogen-activated protein (MAP) kinases become inactive? Ligand diffuses away from the ligand-binding site. Ras hydrolyzes GTP to GDP. Phosphatases remove phosphate groups. Receptor kinases move apart in the membrane.
Phosphatases remove phosphate groups.
metabolic classification of organisms
Photo-auto: sun energy and inorganic carbon source (ie: plants and cyanobacteria) Photo-hetero: sun energy and organic carbon source (ie: heliobacteria and green non-sulfur bacteria) Chemo-auto: chemical energy from inorganic carbon (ie: sulfur-oxidizing bacteria and hydrogen bacteria Chemo-Hetero: chemical energy from organic carbon (ie: most bacteria and animals)
forms of glucose storage in animal and plant cells
Plants: Starch (large, branched chains of glucose stored as granules) Animals: glycogen (large, branched, glucose w/ more branches and chains attached to central protein)
Which structures are large holes filled with cytoplasm, have a continuous plasma membrane, and do not occur in animal cells?
Plasmodesmata
differences in structure of prokaryotes, animal cells, and plant cells
Prokaryotes: no organelles, no nucleus, transcription in cytoplasm, translation in cytoplasm, 1-2 micrometer in size Animal: singe lipid bilayer cell membrane, nucleus contained DNA, membrane-bound organelles, transcription in nucleus, translation in cytoplasm, 10-20 micrometers in size Plant: cell wall, large central vacuole, chlorophyll, chloroplasts, plasmodesmata, NO lysosomes or peroxisomes
What organelle is used to degrade p53?
Proteasome
transmembrane proteins
Proteins that span the entire lipid bilayer; most integral membrane proteins are transmembrane proteins
What role do phosphate groups play in receptor kinase activation?
Provide binding sites to recruit and activate signal-transduction proteins
What type of molecule is not associated with a cell's plasma membrane? Please choose the correct answer from the following choices, and then select the submit answer button. RNA carbohydrate protein phospholipid
RNA
•reactants and products of regeneration • energy requirements
Reactant: 5 triose phosphates ------------Products: 3 5-C RuBP -----------Energy Requirement: ATP
• The reactants and products of Reduction • The energy requirements
Reactants: NADPH + 3-PGA------------Products: triose phosphate ----------------------energy requirements: ATP
In many signaling pathways, once a signaling molecule binds to a receptor, the receptor becomes phosphorylated. This initial phosphorylation step best demonstrates: either cellular response or signal transduction. cellular response. signal transduction. termination. receptor activation.
Receptor Activation
Which type of cell-surface receptor undergoes changes in phosphorylation in response to binding of its ligand? receptor kinase ligand-gated ion channel both the G protein-coupled receptor and the receptor kinase G protein-coupled receptor
Receptor Kinase
Who coined the term "cell"?
Robert Hooke
Which of the following is likely to be the site where the integral membrane proteins are mostly assembled in the cell?
Rough endoplasmic reticulum
Whose work do we attribute the "all known life is made of cells" tenant of the modern cell theory
Schlieden and Schwann
Cyclic AMP (cAMP) is an example of a(n): second messenger. ligand. effector or target protein. G protein.
Second Messenger
The "fluid mosaic model" that states that proteins are floating in a "sea" of lipids was proposed by _________.
Singer and Nickleson
Which of the following statements about communication among bacteria is correct? (Select all correct choices.)
Small peptides can stimulate a DNA-uptake response. Cellular communication in bacteria is based on the same principles as communication within multicellular organisms.
mitochondria
Specialized organelles that harness energy for the cell from chemical compounds like sugars and convert it into ATP
Why don't steroid hormones bind to transmembrane cell-surface receptors? Steroid hormones don't require receptors because they bind directly to DNA. Steroid hormones are not signaling molecules. Steroid hormones are nonpolar and therefore cannot bind to receptors. Steroid hormones are nonpolar and therefore are able to cross the cell's plasma membrane, binding to receptors inside the cell.
Steroid hormones are nonpolar and therefore are able to cross the cell's plasma membrane, binding to receptors inside the cell.
How enzymes achieve catalytic activity
Substrate binds to active site Long version: •Enzyme catalysis occurs in the active site, which uses favorable intermolecular forces to bind its substrate. •The active site orients the substrate in a way that stabilizes transition state and positions it in correct orientation to react with the proper atoms to form the desired product •Critical active site residues are commonly far apart in the primary structure, which allows them to properly align in the active site for catalysis when the protein folds.
Bacteria are rarely larger than 1-2 μm in size, and are typically shaped like rods, spheres, or spirals. What likely accounts for the shape and size of these prokaryotes? Please choose the correct answer from the following choices, and then select the submit answer button. Such shapes maximize the surface area over which nutrients can diffuse into bacteria. Such shapes both facilitate the formation of pili in bacteria and maximize the surface area over which nutrients can diffuse into bacteria. Such shapes facilitate the formation of pili in bacteria. Such shapes likely make it difficult for predators to catch bacteria. Such shapes can accommodate the complex arrangements of plasmids within bacteria.
Such shapes maximize the surface area over which nutrients can diffuse into bacteria.
active transport
The "uphill" movement of substances against a concentration gradient
A vSNARE specific for the plasma membrane comes in contact with a tSNARE of the plasma membrane
The SNARES are compatible and the t and v SNARES wrap around each other using energy from ATP
A vSNARE specific for lysosomes comes in contact with a tSNARE of a plasma membrane. Which response happens?
The SNARES are incompatible and the tethered vesicle releases and leaves
homeostasis
The active regulation and maintenance, in animals, organs, or cells, of a stable internal physiological state in the face of a changing external environment
Why is phosphorylation and dephosphorylation commonly used to regulate signal transduction pathways
The addition or removal of a phosphate group can alter the conformation of cytoplasmic enzymatic proteins, exposing or hiding potential binding sites
Why is phosphorylation and dephosphorylation commonly used to regulate signal transduction pathways?
The addition or removal of a phosphate group can alter the conformation of cytoplasmic enzymatic proteins, exposing or hiding potential binding sites.
photosynthesis
The biochemical process in which carbohydrates are built from carbon dioxide and the energy of sunlight; oxygen is released as a waste product
During the signal transduction process, the signal often triggers a signal transduction cascade. For example: An activated receptor activates hundreds of protein A. Each activated protein A activates hundreds of protein B and so on until a cellular response occurs. What purpose does this cascade serve? The cascade makes signaling easier to shut off or terminate. Having a cascade allows the cell to respond to different signals. The cascade serves to amplify the signal, so one activated receptor can have a significant response. Having several intermediates allows for greater control of the response.
The cascade serves to amplify the signal, so one activated receptor can have a significant response
Which of the following is NOT part of the general response of cells during cellular communications?
The cell automatically returns to its normal activities after the signal has exerted its effect
nuclear envelope
The cell structure, composed of two membranes, inner and outer, that defines the boundary of the nucleus
Predict what would happen if an embryonic epidermal cell switched from expressing E-cadherin to N-cadherin. There would be no effect. The cell would die. The cell would become a neural cell. The cell would leave the epidermis and join the neural cells.
The cell would leave the epidermis and join the neural cells.
Which of the following is NOT true of the plasma membrane?
The composition of the plasma membrane extracellular and intracellular ... highly similar
Which of the following is NOT true of the plasma membrane?
The composition of the plasma membrane extracellular and intracellular layers are highly similar.
cytoplasm
The contents of the cell other than the nucleus
thylakoid
The internal membrane-bound compartment in the center of chloroplasts, consisting of the highly folded thylakoid membrane, which contains light-collecting pigments and is the site of the photosynthetic electron transport chain
dermis
The layer of skin beneath the epidermis, consisting of connective tissue, hair follicles, blood and lymphatic vessels, and glands. It supports the epidermis both physically and by supplying it with nutrients and provides a cushion surrounding the body
chlorophyll
The major photosynthetic pigment contained in the thylakoid membrane; it plays a key role in the chloroplast's ability to capture energy from sunlight. Chlorophyll appears green because it is poor at absorbing green wavelengths
plasma membrane
The membrane that defines the space of the cell, separating the living material within the cell from the nonliving environment around it
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? The mice will have fewer neurons and more glia compared to their normal counterparts. These mice will have more neurons compared to their normal counterparts. These mice will have fewer neurons compared to their normal counterparts. The mice will have fewer glia compared to their normal counterparts. These mice will have more glia compared to their normal counterparts.
The mice will have fewer glia compared to their normal counterparts.
osmosis
The net movement of water molecules from regions of higher water concentrations to regions of lower concentration
spindle apparatus
The organelle formed by microtubules that separates replicated chromosomes during eukaryotic cell division
endoplasmic reticulum (ER)
The organelle involved in the synthesis of proteins and lipids
golgi apparatus
The organelle that modifies proteins and lipids produced by the ER and acts as a sorting station as the move to their final destination
rough endoplasmic reticulum (RER)
The part of the endoplasmic reticulum with attached ribosomes
Predict how phospholipids arrange themselves when they are placed in a nonpolar solution. Please choose the correct answer from the following choices, and then select the submit answer button. The phospholipid would form a liposome. The phospholipid heads would orient toward the solution. The phospholipids would form a bilayer. The phospholipid tails would orient toward the solution.
The phospholipid tails would orient toward the solution.
smooth endoplasmic reticulum (SER)
The portion of the endoplasmic reticulum that lacks ribosomes
turgor pressure
The pressure exerted by water agains an object, which provides structural support for many plants, fungi, and bacteria
protein sorting
The process by which proteins end up where they need to be in the cell to perform their function
endocytosis
The process in which a vesicle buds off from the plasma membrane, bringing material from outside the cell into that vesicle, which can then fuse with other organelles
diffuision
The random motion of individual molecules, with net movement occurring where there are areas of higher and lower concentration of the molecules
Why do the functions of many receptor kinases depend on the fluid nature of the plasma membrane?
The receptor monomers must move together and dimerize to be activated
Why do the functions of many receptor kinases depend on the fluid nature of the plasma membrane?
The receptor monomers must move together and dimerize to be activated.
cytosol
The region of the cel inside the plasma membrane but outside the organelles; the jelly-like internal environment that surrounds the organelles
Phosphatases are a family of enzymes that specifically remove phosphate groups from proteins that were added by protein kinases. Vanadate is an inhibitor of phosphatases in eukaryotic cells. What effect would vanadate have on the response of cells to signals received by receptor kinases?
The response of the cell would last longer than it normally would.
The________ is a place where integral membrane proteins are synthesized.
The rough er
If a cell lacked a cytoskeleton, which of the following would likely be a result? Please choose the correct answer from the following choices, and then select the submit answer button. The shape of the cell would be affected and protein movement in the cell would be affected. The cell would be unable to harness energy. The cell would be unable to carry out translation. The shape of the cell would be impacted. Protein movement in the cell would be affected.
The shape of the cell would be affected and protein movement in the cell would be affected.
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? This signal is likely similar in structure to ligands utilized by eukaryotic cells. This signaling pathway might actually be utilized by both prokaryotes and eukaryotes. This gene expression is likely independent of the presence of the prokaryotic signal. The signal is either similar in structure to a ligand used by eukaryotes, or this signaling pathway is utilized by both prokaryotes and eukaryotes. This prokaryotic signal likely travels directly into eukaryotic cells and acts as a transcription factor.
The signal is either similar in structure to a ligand used by eukaryotes, or this signaling pathway is utilized by both prokaryotes and eukaryotes.
nuclear localization signal
The signal sequence for the nucleus that enables proteins to move through pores in the nuclear envelop
cell theory
The theory that the cell is the fundamental unit of life in all organisms and that cells come only from preexisting cells
When microtubules are arranged in a 9+2, what does this nomenclature refer to?
There are 9 sets of 2 fused microtubules
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? There would be a smaller than normal increase in the rate of DNA uptake. There would be no change in the rate of DNA uptake. There would be a larger than normal increase in the rate of DNA uptake. There would be a decrease in the rate of DNA uptake.
There would be no change in the rate of DNA uptake.
Some lipid rafts are characterized by an accumulation of cholesterol. What does this mean for the fluidity of the raft domain? Please choose the correct answer from the following choices, and then select the submit answer button. These lipid rafts are more fluid than the surrounding membrane at normal temperatures. These lipid rafts are less fluid than the surrounding membrane at low temperatures. These lipid rafts are equally fluid as the surrounding membrane independent of temperature. These lipid rafts are less fluid than the surrounding membrane at normal temperatures.
These lipid rafts are less fluid than the surrounding membrane at normal temperatures.
Which of the following is not a true statement about receptors that are localized to the nucleus? They are synthesized in the cytosol. They carry a nuclear-localization signal. They bind polar ligands. They move through a nuclear pore.
They bind polar ligands.
Gap junctions and plasmodesmata have what feature in common? They both allow direct transport of materials between cells. They both attach to the cytoskeleton. They both are made up of protein subunits located in the plasma membrane. They are both found in plant cells.
They both allow direct transport of materials between cells.
Which of the following is a false statement about the motor proteins myosin and kinesin? They both move along microtubules. They both move cargo to the plus end of a cytoskeletal filament. They both use ATP. None these statements about myosin and kinesin is false.
They both move cargo to the plus end of a cytoskeletal filament.
Why aren't ribosomes considered organelles?
They have no plasma membrane
Match the type of receptor to the correct description
This protein is typically closed and the receptor opens it Correct A. gated channel Correct A. gated channel The sodium potassium pump is an example of this receptor Correct A. gated channel Incorrect B. intracellular kinases After binding to a ligand, two membrane-bound receptors pair up (dimerize). Correct D. receptor kinases Correct D. receptor kinases Active when bound to GTP and contain a GTPase, contains 3 subunits. Correct C. heterotrimeric G proteins Correct C. heterotrimeric G proteins
What is the function of adenylyl cyclase? to form cyclic AMP to phosphorylate cyclic AMP to phosphorylate protein kinase A to form protein kinase A
To form cyclic AMP
If cells had single-layer membranes like micelles, how would the structures of transmembrane proteins be affected? Please choose the correct answer from the following choices, and then select the submit answer button. The structures of transmembrane proteins would remain the same as if cells had lipid bilayers. Transmembrane proteins would only possess hydrophobic regions. Transmembrane proteins would only possess hydrophilic regions. Transmembrane proteins would possess a hydrophobic region in the cell interior and a hydrophilic region in the extracellular space. Transmembrane proteins would possess a hydrophilic region in the cell interior and a hydrophobic region in the extracellular space.
Transmembrane proteins would possess a hydrophobic region in the cell interior and a hydrophilic region in the extracellular space.
By definition lysosome contains two or more acid hydrolases. Thus, the cell can have lysosomes that are specialized at degrading specific compounds.
True
Endocytosis and exocytosis must be in balance if the cell is not to grow or shrink
True
Endocytosis and exocytosis must be in balance if the cell is not to grow or shrink.
True
The outside membrane of the plasma membrane targeted vesicle is the same as the inside of the plasma membrane.
True
organ
Two or more tissues that combine and function together
mechanism and purpose of cyclic electron transport
Used to pump additional protons and increase ATP production...energized electron in Fd sent to Pq to pass through Cyt again and pump more protons
vesicle role in the endomembrane system
Vesicles deliver proteins and lipids from the ER to the Golgi apparatus for modification and final destination sorting
As a scientist you create an artificial cell with a selectively permeable membrane through which only water can pass. You put a 5 M solution of glucose into the cell and you place that cell into a beaker of water. What observations do you expect to see?
Water moves into the cell.
Citric acid cycle: •Where it occurs in the cell. •The number of reactions in this step. •The products produced per acetyl-CoA from this step. •The net products produced per glucose molecule at the end of this step.
Where: mitochondrial matrix Number of Reactions: 8 Products of acetyl-CoA: 1 ATP, 3 NADH, 1 FADH2 Products of glucose: 6 CO2, 10 NADH, 2 FADH2, 4 ATP
Oxidative phosphorylation: •Where it occurs in the cell. •Which complexes in the electron transport chain pump protons. •The order of electron movement through the electron chain from either NADH or FADH2 to complex IV. •How ATP synthase uses the electrochemical gradient to produce ATP -The function of F0 and F1 subunits in ATP synthesis •The net number of ATP produced per glucose molecule at the end of this step.
Where: on mitochondrial inner membrane complexes: Complex 1, 3, and 4 Order: NADH -> Complex 1 -> CoQ -> complex 3 -> cytochrome c -> Complex 4 -ATP synthase is a molecular machine that uses the gradient so protons move down through F0 to the mitochondrial matrix and cause it to rotate in turn causing conformational changes in F1 which catalyzes ADP + P to form ATP Net #: 32 molecules of ATP
How does an adherens junction differ from a desmosome?
While both adherens junctions and desmosomes connect cells by using cadherin proteins, adherens junctions connect to microfilaments while desmosomes connect to intermediate filaments inside the cell.
G protein-coupled receptor
a cell surface receptor that associates with G proteins, proteins that bind to the guanine nucleotides of GTP of GDP
An epithelial tissue is defined as: a network of cells that use chemical communication. a collection of cells that lines cavities or outside surfaces. a few cells embedded into an extensive extracellular matrix. a collection of contractile cells.
a collection of cells that lines cavities or outside surfaces.
What is the very first effect of ligand binding to a G protein-coupled receptor? the release of the alpha subunit of the G protein an exchange of GTP in place of GDP on the alpha subunit of the G protein the activation of an effector protein a conformational change in the cytoplasmic domain of the receptor
a conformational change in the cytoplasmic domain of the receptor
Epidermolysis bullosa is a set of rare genetic disorders that is caused by: an intermediate filament gene that disrupts hemidesmosomes, weakening epidermal cell connections. a keratin gene that disrupts intermediate filaments, weakening epidermal cell connections. a microfilament gene that disrupts desmosomes, weakening epidermal cell connections. All of these choices are correct. a keratin gene that disrupts microfilaments, weakening epidermal cell connections.
a keratin gene that disrupts intermediate filaments, weakening epidermal cell connections.
A molecule that binds to a receptor and activates the receptor is
a ligand
A molecule that binds to a receptor and activates the receptor is __________.
a ligand
Most proteins containing a signal sequence located at their amino terminal ends are sorted to: Please choose the correct answer from the following choices, and then select the submit answer button. the nucleus. a mitochondrion or the rough endoplasmic reticulum. the cytosol.
a mitochondrion or the rough endoplasmic reticulum.
All of the following are properties of at least some prokaryotic cells except: Please choose the correct answer from the following choices, and then select the submit answer button. a nucleus. plasmids. small size. pili.
a nucleus.
Signal transduction results in:
a response by the cell.
A cell that responds to an environmental condition by the release of a chemical is an example of which of the following elements of cellular communication? 1.) a receptor protein 2.) a signaling molecule 3.) None of the other answer options is correct. 4.) a responding cell 5.) a signaling cell
a signaling cell
A chemical that binds to a cell and causes its activity to change is an example of which of the following elements of cellular communication? 1.) a receptor protein 2.) a signaling molecule 3.) None of the other answer options is correct. 4.) a responding cell 5.) a signaling cell
a signaling molecule
In the context of cell signaling, to what does the term ligand refer? the proteins activated as part of a signal transduction pathway a type of gated channel the extracellular domain of a receptor protein a signaling molecule
a signaling molecule
growth factor
a small soluble signaling molecule that helps in the formation of embryos
Enzymes in lysosomes are activated by
acid pH
A cell's plasma membrane contributes to homeostasis by: Please choose the correct answer from the following choices, and then select the submit answer button. maintaining the shape of the cell. functioning as a fluid mosaic of lipid and protein. acting as a selective barrier. defining the boundary between the inside and outside of the cell.
acting as a selective barrier.
MAP kinase pathway
activation of series of kinase pathways
termination
after the signal is terminated it allows for the cell to respond to new signals
Which of the following is NOT a function of the extracellular matrix.
all of these choices are a functions of the extra cellular matrix.
A researcher is studying a G protein-coupled receptor in eukaryotic cells. In one group of cells, he notices that even though a ligand can bind to its G protein-coupled receptor, nothing happens. Why could this happen? Please choose the correct answer from the following choices, and then select the submit answer button. The G protein-coupled receptor might carry a mutation so that it fails to undergo a conformational change upon the binding of its ligand. The G protein-coupled receptor might carry a mutation that affects the receptor's transmembrane portion. These cells might carry mutations in the downstream signaling pathway associated with this G protein-coupled receptor. All of these choices are correct.
all of these choices are correct
The sites where molecules other than substrates bind to an enzyme to alter its activity are called ____________ sites.
allosteric
function of receptor membrane proteins
allow the cell to receive cells from the environment
Dynamic instability of microtubules:
allows microtubules to perform their functions.
A small number of surface receptors can ultimately generate a large intracellular response, as each step of the pathway is often expanded by signal ________.
amplification
receptor kinase
an enzyme receptor where kinase adds a phosphate group to another molecule in a process called phosphorylation; usually becomes activated
why does active transport of molecules across a membrane require ATP?
an input of energy is needed to allow the movement of molecules from an area of low concentration to one of higher concentration
how do eukaryotic plant and animal cells differ from one another?
animal cells do not have chloroplasts and cell walls, and plant cells do
function of anchor membrane proteins
attach to other proteins to help maintain cell structure and shape
Which of the following CORRECTLY lists the types of cellular communication from shortest to longest distance traveled by the signaling molecule to reach its responding cell?
autocrine, paracrine, endocrine
Why oxygen becomes reduced as it gains bonds with hydrogen
bc in O2 form the electrons are shared equally but oxygen is an electron acceptor and the hydrogen donates an electron
Why the total energy available to do cell work after a chemical reaction is less than the total energy available at the beginning of a reaction.
bc some is lost as heat during the reaction according to 2nd law of thermodynamics
Why carbon becomes oxidized as it gains more bonds with oxygen
bc the oxygen is more electronegative and pulls electrons toward it
Why do phosphodiester bonds in ATP have high potential energy
bc the phosphate groups are negatively charged and slightly repel each other so they are very easy to break
Match the organelle with its description. Responses may be used multiple times or not at all. (Type in the letters representing your answers in the below box. No spaces or commas are needed in between answers.) a. endoplasmic reticulum b. Golgi apparatus c. nuclear envelope ____ involved in the sorting of lipids and proteins ____ composed of two membranes ____ composed of multiple cisternae ____ involved in the synthesis of lipids and proteins ____ connected to the endoplasmic reticulum Please type the correct answer in the following input field, and then select the submit answer button or press the enter key when finished.
bcbac
G proteins are those that
bind and hydrolyze GTP and GDP changing tertiary shape in the process
Which of the following is not a function of the signal recognition particle (SRP)? Please choose the correct answer from the following choices, and then select the submit answer button. binds to a channel in the rough endoplasmic reticulum binds to the ribosome targets certain proteins to be synthesized on the rough endoplasmic reticulum halts translation
binds to a channel in the rough endoplasmic reticulum
signaling molecule
binds to a receptor molecule
Clathrin is _______?
both a and c are correct
If the Na+/K+ pump stops working, which of the following will happen to the cell.
both b and c are correct answers
a phospholipid molecule in a membrane can :
both spin (rotate around its vertical axis) and move side-to-side (lateral movement).
Inactivation of a cell-surface receptor depends on: the activity of phosphatases in the cytosol. the binding affinity of the receptor. the concentration of ligand surrounding the cell. both the binding affinity of the receptor and concentration of ligand surrounding the cell.
both the binding affinity of the receptor and concentration of ligand surrounding the cell.
Microfilaments grow longer _______.
by growing more quickly at one end than the other.
Zebrafish embryos change the color of the melanophore cells in their skin to a darker shade:
by kinesin motor proteins moving pigment granules outward from the center of the cell.
difference between carrier and channel proteins
carriers only open to one side or the other channels are just basically tubes
function of enzyme membrane proteins
catalyze reactions at the interior or exterior surface
Prokaryotes absorb their nutrients from the environment. however, prokaryotes also have cell walls. What can you conclude from these statements?
cell walls are permeable, allowing nutrients to pass through
A mutation in the DNA binding domain of a steroid hormone receptor is most likely to affect the
cellular response to the hormone
Which of the following can lysosomes not degrade.
cellulose
Which of the following is NOT found in the extracellular matrix of animal cells? polysaccharide cellulose laminin elastin collagen
cellulose
Which of the following is NOT found in the extracellular matrix of animal cells?
cellulose fibers
Chloroplasts and mitochondria are most closely related to: Please choose the correct answer from the following choices, and then select the submit answer button. None of the other answer options is correct. certain archaea. certain single-celled eukaryotes. certain fungi. certain bacteria.
certain bacteria.
products of cellular respiration
chemical products: CO2 and H2O plus ATP
difference between chemical and thermal energy of a molecule
chemical: form of potential energy held in chemical bonds Thermal: type of kinetic energy corresponding to random motion of molecules
Which of the following is a pigment associated with chloroplasts that plays a role in energy harvesting? Please choose the correct answer from the following choices, and then select the submit answer button. ATP melanin thylakoid chlorophyll fibril
chlorophyll
pigments that plants use to absorb light
chlorophyll and xanthophyll
Which of the following is not part of the endomembrane system? Please choose the correct answer from the following choices, and then select the submit answer button. nuclear envelope vesicles chloroplasts lysosomes
chloroplasts
Some lipid rafts are characterized by an accumulation of cholesterol. What does this mean for the fluidity of the raft domain?
cholesterol decreases the fluidity of the membrane at normal temperatures
Which side of the Golgi apparatus does vesicles from the transition ER enter?
cic cisternae
Which side of the Golgi apparatus does vesicles from the transition ER enter?
cis cisternae
Membrane bound flattened sacs are
cisternae
Which of the following is a component of the extracellular matrix produced by an animal cell? All of these choices are correct. cellulose cadherin collagen
collagen
A molecule that closely resembles the shape and/or type of a substrate for an enzyme might serve as a(n)
competitive inhibitor
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: components of both the extracellular matrix and cytoskeleton. components of cell junctions. components of the cytoskeleton. components of the extracellular matrix. components of microvilli.
components of cell junctions
juxtacrine signaling
contact dependent signaling; transmembrane protein on the surface on one cell acts as the signaling molecule and the transmembrane protein on the surface of the adjacent cell acts as the receptor
An amphipathic molecule is one that:
contains both polar and nonpolar regions
An amphipathic molecule is one that: Please choose the correct answer from the following choices, and then select the submit answer button. contains both polar and nonpolar regions. has a head and tail domain. can fully dissolve in water. makes up a membrane.
contains both polar and nonpolar regions.
The first organisms thought to use two photosystems to oxidize water were _________
cyanobacteria
A bacterial cell, a plant cell, and an animal cell have which of the following structures in common? Please choose the correct answer from the following choices, and then select the submit answer button. cytoplasm nucleus cell wall nucleoid vacuole
cytoplasm
a bacterial cell, a plant cell and an animal cell have which of the following structures in common? -cytoplasm -cell wall -vacuole -nucleus -nucleoid
cytoplasm
Ras
cytoplasmic signaling proteins which is similar to alpha subunit of G proteins
The _____ serves to organize and lower the entropy of the cytosol of the eukaryotic cell.
cytoskeleton
The _______ is very important in organizing the cytosol domain of the cell.
cytoskeleton
Cell shapes are largely determined by:
cytosolic proteins that assemble into structures called cellular junctions. adhesion proteins that assemble at cell surfaces. cytoskeletal protein networks in the cytoplasm. a mesh of proteins and polysaccharides in the extracellular matrix.
Which one of the following pairs includes junctional complexes that perform similar functions?
desmosomes and adherens junctions
membrane potential
difference in electrical charge across a membrane
The high variability of the types of G protein-coupled receptors allows for:
different types of cells to respond to different types of signals
direction of solute movement in diffusion
diffusion: solute molecules move from high concentration to low concentration
what does the ΔG from hydrolysis of ATP do?
drives reactions and becomes replenished energy from hydrolyzing ATP is used to make ΔG negative and the reactions spontaneous
imagine a cell that has a membrane composed mostly of lipids with saturated fatty acid tails, and that this membrane also has low cholesterol content. what are the characteristics of this cell membrane?
due to its low cholesterol content, the cell membrane would lose its fluidity at cold temperatures
Which motor protein(s) would you find in a flagellum? both myosin and dynein kinesin myosin dynein
dyne
The movement of flagellum or cilium is due to ATP interacting with _______ and the sliding of one microtubule along another.
dynein
What protein uses ATP and moves vesicles from the early to late endosome?
dynein
When the pH drops and the receptor release the LDL particles a vesicle called ... the receptors up, forms a new vesicle that returns the receptors to the plasma membrane...
early endosome
Which of the following types of cell signaling generally occurs between cells that are distant from each other? 1.)endocrine 2.)All of these choices are correct. 3.)autocrine 4.)paracrine
endocrine
An increased heart rate caused by the release of adrenaline from the adrenal glands is an example of
endocrine signaling
An increased heart rate caused by the release of adrenaline from the adrenal glands is an example of _________.
endocrine signaling
Cell signaling over a long distance is known as:
endocrine signaling
Which one of the following is most closely related to archaea? Please choose the correct answer from the following choices, and then select the submit answer button. eukaryotes both eukaryotes and bacteria neither eukaryotes nor bacteria bacteria
eukaryotes
difference between exocytosis and endocytosis
exo: the process of a vesicle fusing with the plasma membrane and delivering its contents outside of the cell endo: process of material outside the cell being brought into a vesicle
the controlled release of cellular material stored in membrane bound vesicles to the outside of the cell is an example of :
exocytosis
A single molecule is always either hydrophobic or hydrophilic, and can never possess (at the same time) a region that is hydrophobic and a region that is hydrophilic. Please choose the correct answer from the following choices, and then select the submit answer button. true false
false
Mitochondria and chloroplasts are integral parts of the endomembrane system and are specifically connected to the endoplasmic reticulum. Please choose the correct answer from the following choices, and then select the submit answer button. true false
false
Prokaryotes contain nucleoids, which are similar to nuclei in that they contain rudimentary chromosomes referred to as plasmids. Please choose the correct answer from the following choices, and then select the submit answer button. true false
false
The ER contains multiple cisternae which have their own distinct lumen and membranes.
false
The inside membrane of the plasma membrane targeted vesicle is the same as the inside of the plasma membrane.
false
Kohler and Lipton first discovered platelet-derived growth factor by observing that fibroblasts:
fibroblasts grew better in cell culture when blood serum was added to the growth medium instead of blood plasma.
Which of the following is not true of the cytoskeleton elements called microfilaments.
found in both eukaryotes and prokaryotes
direction a solute travels when it moves with the gradient
from area of high concentration to are of low concentration
Which proteins located in two different membranes fuse together and allow phospholipids to flow from one membrane to the other?
fusogens
All cells have: Please choose the correct answer from the following choices, and then select the submit answer button. a cell wall. genetic information. a nucleus. internal compartments.
genetic information.
four stages of cellular respiration
glycolysis, pyruvate oxidation, citric acid cycle, oxidative phosphorylation
Protein sorting: SRP signal
goes to lumen of organelles or secreted out of the cell, special N-terminal signal attracts signal recognition particle (SRP) that binds to ribosome, pauses translations, brings ribosome to the RER, SRP interacts w/ receptor, dissociates fromribosome so it can translate protein into a channel in the RER, protein synthesized into lumen of ER and endomembrane system.
Protein sorting: N-terminal (amino-terminal) signal
goes to mitocondria or chloroplast
Protein sorting: Internal signal
goes to nucleus requires a nuclear localization signal to be actively transported into the nucleus
Which organelle separates the different hydrolases from other kinds of proteins so that they eventually end up in specific lysosomes?
golgi
cilia
hairlike organelles that propels the the movement of cells or of substances within cells or out of the body; shorter than flagellum
Which one of the following properly groups a junctional complex with a cytoskeletal structure and cell adhesion molecule?
hemidesmosome, intermediate filament, integrin
The interior region of a phospholipid bilayer is characterized as:
hydrophobic
Why polar and large molecules have trouble crossing a lipid bilayer.
hydrophobic interior of the membrane prevents ions, charged, and polar molecules from crossing they are too big to pass through the membrane without help
Are there hydrophobic and hydrophilic regions of a transmembrane protein?
hydrophobic residues on surface
effects of placing a cell in a isotonic, hypotonic, or hypertonic solution
hyper: (higher concentration outside) water leaves and cell shrinks hypo: "O" (lower concentration of solute outside) water goes in, cell can blow up iso: (same inside and out) cell maintains its true shape
An animal cell crenulates when it is exposed to a ______.
hypertonic solution
Where would you find a cell adhesion molecule? in a cell junction near the centrosome in the microvilli in a cilium
in a cell junction
Synthesis of a protein destined to function in the nucleus occurs: Please choose the correct answer from the following choices, and then select the submit answer button. in the cytosol. on the outer leaf of the nuclear envelope. on the rough endoplasmic reticulum. in the Golgi apparatus.
in the cytosol.
Cells change the composition of their plasma membranes as a response to changing environment ... How would the cell change the membrane in response to colder temperatures?
increase the amount of unsaturated fatty acids
Structures known as microvilli are associated with: adhesion to the extracellular matrix. increased surface area for nutrient absorption. communication between cells. increased surface area for gas exchange.
increased surface area for nutrient absorption.
effect of an inhibitor or activator on enzyme activity
inhibitors decrease enzyme activity activators increase enzyme activity
difference between integral and peripheral membrane proteins
integral is permanent and peripheral is temporary
Protein sorting: SRP and signal-anchor sequence
integral membrane protein of the endomembrane system or plasma membrane. • The protein is brought to the RER channel using the SRP receptor system. As the protein is translated into the channel, the signal-anchor sequence migrates into the membrane of the RER. • The N-terminal domain will end up facing the lumen of an organelle or the extracellular space. • The C-terminal domain will always face the cytoplasm. -
Membrane integrity during purification of integral and peripheral membrane proteins
integral proteins will rip the membrane if removed (fluid but will ruin)
how integral and peripheral interact with membrane
integral: cant separate without destroying membrane, span whole membrane, hydrophobic residue on surface peripheral: non-covalent interactions, can be interior or exterior, some have fatty acid that anchor to membrane,
second messengers
intermediate cytosolic signaling molecules ie. cAMP
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. intermediate filaments microtubules both intermediate filaments and microfilaments microfilaments
intermediate filaments
Which of the following provide structural support for epithelial cells, such as those in the skin (keratinocytes)? microfilaments intermediate filaments microtubules microfilaments and intermediate filaments microtubules and microfilaments
intermediate filaments
Cellular responses that result from receptor kinase activation tend to:
involve changes in gene expression.
paracrine signaling
involves two cells that are close together, therefore the signal only needs to diffuse a short distance
An advantage to signal transduction pathways having several stages or parts is ______.
it greatly amplifies a single signal molecule
why does water prefer facilitated diffusion through aquaporins in membranes
it moves much more quickly
why is the energy from a molecule of ATP required by the sodium potassium pump?
it provides the energy required to move sodium and potassium ions against their concentration gradients
A --- is a protein that attaches phosphate groups to molecules.
kinase
Which type of protein adds a phosphate group to another molecule?
kinase
The molecular motor _______ move vesicles in the - to + direction from the Golgi to the plasma membrane on microtubules.
kinesin
Zebrafish embryos change the color of the melanophore cells in their skin to a darker shade by: kinesin motor proteins moving pigment granules inward toward the center of the cell. dynein motor proteins moving pigment granules outward from the center of the cell. dynein motor proteins moving pigment granules inward toward the plus end of microtubules. kinesin motor proteins moving pigment granules outward from the center of the cell. dynein motor proteins moving pigment granules inward toward the center of the cell.
kinesin motor proteins moving pigment granules outward from the center of the cell
difference between kinetic and potential energy
kinetic: energy of motion, associated with any kind of motion (photon, electron, molecule, etc.) potential: stored energy -depends on structure and position (ball at top of a hill)
Which of the following molecules does not easily diffuse across a plasma membrane? Please choose the correct answer from the following choices, and then select the submit answer button. small polar molecules large polar molecules gases both small and large polar molecules
large polar molecules
A _______ is a term given to a molecule that binds to a receptor causing it to carry out its function.
ligand
Which type of receptor is involved in rapid responses of muscle cells and neurons?
ligand-gated ion channel
Heterotrimeric G proteins are inactive when the alpha subunit is bound to GDP. When a ____ binds to a ______, changes occur in the alpha subunit and it becomes active.
ligand; receptor
lipid raft
lipids assembled in a defined patch in the cell membrane
structure of vesicles
liposome structure with proteins in its membrane that direct it to its target location, interior can carry proteins or other substances such as signaling hormones or neurotransmitters
A vesicle is most similar to a: Please choose the correct answer from the following choices, and then select the submit answer button. micelle. lipid raft. bilayer. liposome.
liposome.
how can lysosomal enzymes that work best at a pH of 5 be fully functional if the pH pf the cytoplasm is 7?
lysosomal enzymes are separated from the cytoplasm by the membrane surrounding the lysosome
Which eukaryotic organelle is associated with the breakdown of macromolecules? Please choose the correct answer from the following choices, and then select the submit answer button. the Golgi apparatus mitochondria lysosome endoplasmic reticulum
lysosome
a cell has a mutation that prevents it from breaking down unwanted proteins present in vesicles. which cellular structure is most likely to be disrupted by this mutation?
lysosomes
Which method of movement through the Golgi moves one entire cisternae forward because a cis cisternae pushes it?
maturing cisternae model
definition of the plasma membrane
membrane that defines the cell (maintains internal conditions)
The cytoskeleton of animal cells includes:
microtubules, microfilaments, and intermediate filaments.
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 _____. minus end; kinesin plus end; kinesin plus end; dynein minus end; dynein
minus end; dynein
Which molecular motor would most likely be involved in muscle contractions?
myosin
_______ motors travel along microfilaments like dynein travels across microtubules.
myosin
The part of a membrane protein that is embedded within the phospholipid bilayer is primarily composed of amino acids that are _______
non-polar.
which component is part of the endomembrane system of a eukaryotic cell? -chromosomes -ribosomes -nuclear envelope, golgi apparatus, and the endoplasmic reticulum all make up the endomembrane system -plasma membrane
nuclear envelope, golgi apparatus, and the endoplasmic reticulum all make up the endomembrane system
Which type of signal receptor does NOT generally involve transduction of a signal with the transfer of a phosphate group? (Select all correct choices.)
nuclear receptor ligand-gated ion channel nuclear receptor
activated
on binding the signal the receptor is activated
signal transduction
once activated the receptor transmits the message though the cytoplasm, often by intracellular signalingn pathways or cascades
Identify the electron acceptor, electron donor, oxidizing agent, and reducing agent in the net reaction of glucose in cellular respiration
oxygen is the electron acceptor and oxidizing agent glucose is electron donor and it is the reducing
Communication between neurons is an example of which type of cell signaling?
paracrine
difference between passive and facilitated diffusion
passive diffusion is the free, unassisted movement of solute molecules from an area of high to low concentration facilitated diffusion uses a gradient also but has to use a protein channel or carrier
Found in the middle lamella of plant cells, _____ is a key carbohydrate. In plants, it is highly charged and water attracting. This function is similar to mucous in animals.
pectin
Which enzyme removes an inorganic phosphate (PO4) from a substrate?
phosphatase
Which enzyme removes an inorganic phosphate (PQ4) from a substrate?
phosphatase
Which of the following lipid composition options has the least membrane fluidity? Please choose the correct answer from the following choices, and then select the submit answer button. phospholipids with long-chain, unsaturated fatty acids phospholipids with long-chain, saturated fatty acids phospholipids with short-chain, saturated fatty acids phospholipids with short-chain, unsaturated fatty acids
phospholipids with long-chain, saturated fatty acids
Enzymatic receptors typically activate intracellular proteins by ___________.
phosphorylation
Which of the following involves taking in small particles and molecules into the cell.
pinocytosis
Most cell membranes originate in the
plasma membrane
Which type of cellular junction(s) allow(s) for the movement of proteins and transfer RNA molecules? both plasmodesmata and gap junctions plasmodesmata desmosomes gap junctions
plasmodesmata
A cell placed into a hypertonic solution will _____.
plasmolyse
researchers seldom find prokaryotic cells that are greater than 100 micrometers in diameter. why would the size of the prokaryote cells be restricted?
prokaryotic cells must absorb all of their nutrients from their environment and therefore require a high surface area to volume ratio
Which of the following is NOT a part of the MAP kinase pathway?
pyrophosphatase enzyme terminates the cellular response.
the process of diffusion requires :
random movement of molecules
• The reactants and products of carboxyloation • The energy requirements
reactants CO2 + 5-C molecule (RuBP) and catalyzed by rubisco..... products 2 3-PGA -----------energy requirement = none-----------
A researcher is using a small molecule as an inhibitor to manipulate a signaling pathway. This inhibitor prevents phosphorylation and most likely targets a: phosphatase. G protein. G protein-coupled receptor. ligand-gated ion channel. receptor kinase.
receptor kinase
ligand-gated ion channels
receptors that alter the flow of ions across the plasma membrane when bound by their ligand
Protein sorting: No peptide signal
remains in the cytoplasm
phosphateses
remove a phosphate group in a process called dephosphorylation, usually becomes deactivated
Match the appropriate type of transport across the membrane to the description.
requires transmembrane proteins. Correct E. all of these choices Correct E. all of these choices describes movement of one substance across the membrane at a time in one direction. Correct B. uniport Correct B. uniport describes the movement of two substances across the membrane at the same time in opposite direction. Correct C. antiport Correct C. antiport describes the movement of two substances across the membrane at the same time in same direction. Correct A. symport Correct A. symport
difference between reversible and irreversible inhibitors
reversible: form weak interactions w/ enzymes and eventually dissociate irreversible: form covalent bonds w/ enzymes and irreversibly inactivate them
Cyclic AMP (cAMP) is an example of a(n):
second messenger.
The _______ is the last layer of the plant cell wall produced, consisting mostly of cellulose and lignin. This layer is very rigid and inflexible.
secondary wall
An example of a --- is when one ligand binds to one receptor and in turn activates ... These proteins activate another -100 proteins which finally result in a change within the cell.
signal amplification
Heterotrimeric G proteins are likely to be associated with --- systems in cells.
signaling
endocrine signaling
signaling by means of molecules that travel through the blood stream
ligand
signaling molecule
How can organisms use a single photosystem with compounds such as H2S?
single photosystem uses electrons to synthesize NADPH (water not used as electron donor so no O2 produced) products of H2S oxidation are water and elemental sulfur (or sulfate ions) Photoheterotrophs (like bacteria in sulfur springs)use this method.
signaling cell
source of the signaling molecules
ligand-binding site
specific place on receptor protein where ligand binds
Why spontaneous reactions do not always occur quickly.
spontaneous doesn't mean actually spontaneous it just means a reaction is exergonic an releases energy. it does NOT need energy input to start the reaction
relationship between bond strength and potential energy
stronger bonds release less energy than weak bonds bc they require more energy input to break them
The sodium potassium pump in the plasma membrane is an example of _____.
symport
Which of the following eukaryotic cell structures plays a role in protein trafficking and sorting? Please choose the correct answer from the following choices, and then select the submit answer button. the Golgi apparatus vacuoles the endoplasmic reticulum lysosomes mitochondria
the Golgi apparatus
GTP binding occurs on which subunit of a G protein? GTP binds both beta and gamma subunits. the alpha subunit the beta subunit the gamma subunit
the alpha unit
binding affinity
the amount of time a signaling molecule remains bound to its receptor depends on hpw tightly the receptor hold on to it
Placing celery sticks in fresh water will make them more turgid and harder. This is because _______
the celery is hypertonic to fresh water.
The term homeostasis refers to the ability of: Please choose the correct answer from the following choices, and then select the submit answer button. the cell to seek out an optimal environment. molecules to undergo net movement by diffusion. the cell to control and maintain its internal environment. the plasma membrane to control what enters a cell.
the cell to control and maintain its internal environment.
How does negative feedback regulate metabolic pathways
the final product of a pathway inhibits the first step
What accounts for the ability of vesicles to fuse with different membrane compartments in the cell? Please choose the correct answer from the following choices, and then select the submit answer button. the cell's cytoskeleton the fluid nature of the phospholipid bilayer transport proteins peripheral membrane proteins
the fluid nature of the phospholipid bilayer
imagine that you have two blades of grass. one is from a normal plant, and the other is from a mutant plant that cannot absorb water into its vacuoles. how will the structure of these two blades of grass compare?
the grass blade from the mutant plant will appear limp compared to that from the normal plant
responding cell
the location of the receptor molecule
A cell biologist has developed a new drug that will block the cis face of the Golgi apparatus. If eventually approved by the FDA, she wants to use this new drug to aid cancer patients. What specifically will this drug prevent from happening inside a cancer cell?
the movement of the lipids and proteins from the endoplasmic reticulum to the Golgi apparatus
in the example of secondary active transport, what would happen if ATP suddenly became unavailable for step 1 in panel a of the figure shown?
the movement of the molecules through the antiporter would continue for a while until the proton gradient was depleted
The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on: the presence of the appropriate receptors on the cells of the target tissue or organ. nothing; all hormones of the body are able to stimulate all cell types because hormones are powerful and nonspecific. the location of the tissue or organ with respect to the circulatory path. the membrane potential of the cells of the target organ.
the presence of the appropriate receptors on the cells of the target tissue or organ.
The process of diffusion requires: Please choose the correct answer from the following choices, and then select the submit answer button. ATP. transport proteins. the random movement of molecules. a concentration gradient.
the random movement of molecules.
definition of cellular respiration
the series of catabolic reactions that produce energy in the form of ATP
cellular response
the signal transduction elicits a response from the cell which can happen through activation of enzymes or activation on genes that cause the cell to divide or change
based on the two step model of glucose transport, what would happen if the rate of function of the sodium potassium pump increased?
the sodium potassium pump would make a stronger sodium gradient, so more glucose could be transported across the membrane
in the kidney, glucose transport across the cell membrane is the result of a combination of two steps of active transport. refer to the figures shown. the first step involves a primary active transport system preformed by the sodium potassium pump. it uses the energy from ATP hydrolysis to move sodium ions out of the cell and potassium ions into the cell. the second step involves a secondary active transport symporter that uses the energy in the sodium that uses the energy in the sodium gradient created by the first step. this second step moves glucose, as well as sodium ions that move down their concentration gradient, into the cell. based on the two step model of glucose transport, what would happen if the supply of ATP was depleted from the cell?
the sodium potassium pump would make less of a sodium gradient, so less glucose could be transported across the membrane
Which one of the following is an example of secondary active transport? Please choose the correct answer from the following choices, and then select the submit answer button. the use of a chemical gradient to generate an electrical gradient the movement of potassium ions following the initial movement of sodium ions the use of more than one type of transport protein for the movement of a molecule the use of an electrochemical gradient of one molecule to move a second molecule
the use of an electrochemical gradient of one molecule to move a second molecule
Which of the following is a mesh-like attachment between cells formed by binding of transmembrane proteins of one cell to the same protein type on the adjacent cell, preventing substances from passing between cells? desmosome tight junction adherens junction hemidesmosome
tight junction
What is the function of the contractile vacuole? Please choose the correct answer from the following choices, and then select the submit answer button. to help single-celled organisms change shape in response to environmental changes to help single-celled organisms maintain homeostasis in a hypotonic environment to maintain cell shape through turgor pressure to help single-celled organisms maintain homeostasis in a hypertonic environment
to help single-celled organisms maintain homeostasis in a hypotonic environment
Which side of the Golgi apparatus do vesicles depart from and go to different places in the cell?
trans cisternae
When something is endocytosed from one part of the cell and moved to the other side of the cell and exocytosed
transcytosis
which of the following would be synthesized on the rough endoplasmic reticulum? -transmembrane protein receptors -nuclear proteins -cytoskeleton proteins -mRNAs
transmembrane protein receptors
Signaling molecules involved in paracrine and autocrine signaling: remain attached to the plasma membrane. travel by diffusion. travel in the circulatory system.
travel by diffusion
Mitochondria and chloroplasts both have inner and outer membranes. Please choose the correct answer from the following choices, and then select the submit answer button. true false
true
Which method of movement through the Golgi is temporary fusion of two cisternae?
tubular connection model
The structure of phospholipids.
two fatty acids connected to glycerol with a phosphate and polar group attached
Which amino acid(s) is/are involved in signaling?
tyrosine threonine serine
_________ is a molecule that is important in tagging worn out organelles and molecules for digestion.
ubiquitin
If a single substance is actively transported across the cell membrane in only ... transport system is...
uniport
If a single substance is actively transported across the cell membrane in only one directions the transport system is __________.
uniport
How chemical reactions are linked to form metabolic pathways
uses products of one reaction as energy fro the next
Which type of SNARES are located on the vesicle membrane?
v SNARES
Which method of movement through the Golgi uses vesicles that bleb off and move to the next cisternae?
vesicle transport model
direction of water movement in osmosis
water moves from an area of high water concentration (low solute) to an area of low water concentration (high solute)
processes in the PETC that increase H+ concentration in the lumen
water oxidation and Cyt pumping
dimerization
when a signaling molecule binds to the extracellular portion of the receptor, a conformational change causes the receptor to partner up with another recpetor kinase bound to another molecule of the same ligand;cytoplasmic kinase domains of the paired recptors are activated which causes them to phosphorylate each other
How reversible reactions can be driven by changing reactant or product (Le Châtelier's principle).
when a stress is placed on a reversible reaction, the system responds by changing the rate of the forward or reverse reaction in the direction that relieves that stress. Increasing reactants/ decreasing products favors forward reaction (right) Decreasing reactants/ increasing products favors the reverse reaction (left)
autocrine signaling
where signaling cell and responding cell are one and the same
receptor molecule
where the signaling molecule binds
The difference in components and structure of lipid micelles, bilayers, and liposomes.
~Fatty acids form micelles spontaneously in solution -Phospholipids form bilayers with the tails buried away from the solvent -Bilayers that are large enough will form a liposome, sealed nature of the liposome makes it an effective membrane
How chain length and saturation of fatty acids on phospholipids is related to membrane fluidity
~Increasing saturation and chain length decreases fluidity ~Decreasing saturation and chain length increases fluidity
function of lysosomes in endomembrane system
~Lysosomes are specialized vesicles that the Golgi creates -breakdown macromolecules in an acidic environment -maintain a pH of 5 by actively pumping protons inside.
function of the endoplasmic reticulum in the endomembrane system
~endoplasmic reticulum is continuous with the nuclear envelope. ~rough ER is where ribosomes bind to translate proteins into the lumen or membrane of the ER. ~smooth ER is the primary site of lipid synthesis and ER vesicle production
function of the nuclear envelope in the endomembrane system
~has two bilayers with nuclear pores that allow passive and active transport across membrane ~Some portions of the surface of the nuclear envelope directly interact with the cytoplasm, allowing proteins with nuclear localization signals to actively transport into the nucleus and mRNA to actively transport out.
function of Golgi apparatus in the endomembrane system
~main location of carb synthesis and glycosylation, (addition of sugars to proteins or lipids) ~sends proteins and lipids to interior or membrane of organelles, such as the lysosome, the plasma membrane, or secrete them from the cell -makes lysosomes
definition of ΔG, ΔH, and ΔS
ΔG: difference in Gibb's free energy (amount of energy available to do work) of reactants and products ΔH: (enthalpy) change in total energy available (chemical and thermal) ΔS: (entropy) change in number of possible arrangements
cholesterol effect on membrane fluidity as temperature changes
• At warm temperatures the rigid ring structure of cholesterol reduces phospholipid mobility, decreasing fluidity • At low temperatures cholesterol prevents close packing of phospholipids, increasing fluidity
what makes the plasma membrane selectively permeable
• Some molecules can enter and exit freely • Some can move under specific conditions • Others cannot cross the membrane at all
function of transporter membrane proteins
• Transporters move ions or molecules across membranes • Channels allow molecules to move through them • Carriers facilitate movement by changing shape
How a catalyst increases the rate of a reaction.
•Activation energy is decreased •ΔG is unaffected
flow of atoms and energy in cellular respiration
•Carbons from C-C and C-H bonds in glucose are oxidized to C=O bonds. •The energy is transferred to ATP -Directly through substrate-level phosphorylation -Indirectly through electron carriers that deliver high energy electrons to the electron transport chain. •The energy transfer from glucose to ATP is 34% efficient (66% of energy is lost as heat). -Combustion engines are about 25% efficient.
Exergonic Reactions vs. endergonic reactions
•Exergonic reaction: net release of free energy (-ΔG) and spontaneous, reactions that lower enthalpy (-H) and increase entropy (+S) •Endergonic reactions: net use of free energy (+ΔG) and are non-spontaneous, reactions that increase enthalpy (+H) and decrease entropy (-S)
The structure of cholesterol
•Hydrophilic hydroxyl group •Hydrophobic ring group and hydrocarbon tail
difference between primary and secondary active transport
•Primary active transport uses ATP to move one or more compounds against their respective chemical gradients •Secondary active transport uses ATP to create a chemical or electrochemical gradient. The gradient is released and the movement of the actively transported compound is used to transport a second compound against its gradient. •Compounds can move in the same direction across a membrane while moving in opposite gradient directions.
range of enzyme specificity
•Specific to a single substrate: succinate dehydrogenase, glucokinase •Specific to a single compound in a particular bond type: β-galactosidase •Specific to a general structural feature: hexokinase, acetalcholinesterase
How other sugars, fatty acids, and amino acids enter cellular respiration as intermediates.
•Sugars tend to enter as glycolysis intermediates •Fatty acids undergo β-oxidation, which produces many NADH and FADH2, as well as acetyl-CoA that enters the citric acid cycle. •Amino acids are converted into various citric acid cycle intermediates.