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Bio 130

Pataasin ang iyong marka sa homework at exams ngayon gamit ang Quizwiz!

cellula

"little rooms"; from the holes of corks

hydrophobic

"water fearing"

hydrophillic

"water loving"

During transcription, in what direction is (1) RNA synthesized and (2) the DNA template "read"? (1) 5'→;3' (2) 5'→;3' (1) 5'→3'; (2) 3'→5' (1) 3'→;5'; (2) 3'→5' (1) 3'→5'; (2) 5'→3'

(1) 5'→3'; (2) 3'→5'

Chiasma

(plural, chiasmata) The X-shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during meiosis.

Give three examples of epithelial sheets found in the human body.

-bladder -intestinal tract -heart -skin

Binomial Nomenclature

2-part naming process; 1st part genus and 2nd part is specific epithet (species descriptor).

Put the following events of transcription in chronological order. 1. Sigma binds to the promoter region. 2. The double helix of DNA is unwound, breaking hydrogen bonds between complementary strands. 3. Sigma binds to RNA polymerase. 4. Sigma is released. 5. Transcription begins. 3, 2, 1, 4, 5 2, 3, 1, 4, 5 3, 1, 2, 5, 4 2, 3, 4, 5

3, 1, 2, 5, 4

The direction of synthesis of an RNA transcript is _____. 1' —> 5' 5' —> 3' 1' —> 3' 3' —> 5' 2' —> 4

5' —> 3'

According to the fluid mosaic model of cell membranes which of the following is a true statement about membrane phospholipids? A) They can move laterally along the plane of the membrane. B) They frequently flip-flop from one side of the membrane to the other. C) They occur in an uninterrupted bilayer with membrane proteins restricted to the surface of the membrane. D) They are free to depart from the membrane and dissolve in the surrounding solution. E) They have hydrophilic tails in the interior of the membrane

Familial hypercholesterolemia is characterized by which of the following?A) defective LDL receptors on the cell membranes B) poor attachment of the cholesterol to the extracellular matrix of cells C) a poorly formed lipid bilayer that cannot incorporate cholesterol into cell membranes D) inhibition of the cholesterol active transport system in red blood cells E) a general lack of glycolipids in the blood cell membranes

In most cells there are electrochemical gradients of many ions across the plasma membrane even though there are usually only one or two electrogenic pumps present in the membrane. The gradients of the other ions are most likely accounted for by A) cotransport proteins. B) ion channels. C) carrier proteins. D) B and C only E) A B and C

The difference between pinocytosis and receptor-mediated endocytosis is that A) pinocytosis brings only water into the cell but receptor-mediated endocytosis brings in other molecules as well. B) pinocytosis increases the surface area of the plasma membrane whereas receptor-mediated endocytosis decreases the plasma membrane surface area. C) pinocytosis is nonselective in the molecules it brings into the cell whereas receptor-mediated endocytosis offers more selectivity. D) pinocytosis requires cellular energy but receptor-mediated endocytosis does not. E) pinocytosis can concentrate substances from the extracellular fluid but receptor-mediated endocytosis cannot.

The presence of cholesterol in the plasma membranes of some animals A) enables the membrane to stay fluid more easily when cell temperature drops. B) enables the animal to remove hydrogen atoms from saturated phospholipids. C) enables the animal to add hydrogen atoms to unsaturated phospholipids. D) makes the membrane less flexible allowing it to sustain greater pressure from within the cell. E) makes the animal more susceptible to circulatory disorders.

The sodium-potassium pump in animal cells requires cytoplasmic ATP to pump ions across the plasma membrane. When the proteins of the pump are first synthesized in the rough ER what side of the ER membrane will the ATP binding site be on? A) It will be on the cytoplasmic side of the ER. B) It will be on the side facing the interior of the ER. C) It could be facing in either direction because the orientation of proteins is scrambled in the Golgi apparatus. D) It doesn't matter because the pump is not active in the ER.

Which of the following factors would tend to increase membrane fluidity? A) a greater proportion of unsaturated phospholipids B) a greater proportion of saturated phospholipids C) a lower temperature D) a relatively high protein content in the membrane E) a greater proportion of relatively large glycolipids compared with lipids having smaller molecular masses

Which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures? A) The double bonds form kinks in the fatty acid tails forcing adjacent lipids to be further apart. B) Unsaturated fatty acids have a higher cholesterol content and therefore more cholesterol in membranes. C) Unsaturated fatty acids permit more water in the interior of the membrane. D) The double bonds block interaction among the hydrophilic head groups of the lipids. E) The double bonds result in shorter fatty acid tails and thinner membranes.

Which of the following is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold? A) by increasing the percentage of unsaturated phospholipids in the membrane B) by increasing the percentage of cholesterol molecules in the membrane C) by decreasing the number of hydrophobic proteins in the membrane D) by co-transport of glucose and hydrogen E) by using active transport

Which of the following span the phospholipids bilayer usually a number of times? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly? A) CO2 B) an amino acid C) glucose D) K+ E) starch

Who proposed that membranes are a phospholipid bilayer between two layers of hydrophilic proteins? A) H. Davson and J. Danielli B) I. Langmuir C) C. Overton D) S. Singer and G. Nicolson E) E. Gorter and F. Grendel

TATA box

A DNA sequence in eukaryotic promoters crucial in forming the transcription initiation complex.

Mutation

A change in a species over an extended period of time that has a beneficial use.

Concentration Gradient

A difference in the concentration of a substance across a distance

Increase

A gradual rise in cyclins will __________ the transcription of the cyclin gene

Gamete

A haploid cell such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote.

Antiport

A membrane transport process that carries one substance in one direction and another in the opposite direction.

Symport

A membrane transport process that carries two substances in the same direction across the membrane.

Tetrad

A paired set of homologous chromosomes, each composed of two sister chromatids. These form during prophase I of meiosis.

Cyclin

A regulatory subunit - It's levels oscillate throughout the cell cycle

Refer to the figure. During elongation, which site in the ribosome represents the location where a codon is being read? small subunit A site E site P site

A site

Transcription begins at a promoter. What is a promoter? A site in DNA that recruits the RNA Polymerase Part of the RNA molecule itself A nontranscribed sequence on the DNA A site found on the RNA polymerase A site where many different proteins will bind

A site in DNA that recruits the RNA Polymerase

Prophase

A stage in mitosis where the chromosomes condense, mitotic spindle forms

How does termination of translation take place? The poly A tail is reached. The 5' cap is reached. The end of the mRNA molecule is reached. A stop codon is reached.

A stop codon is reached.

At which site do new aminoacyl tRNAs enter the ribosome during elongation? A site P site B site E site

A-site

If the DNA code for a particular amino acid is AGT, then the anticodon on the tRNA would be _____. AGU UCA AGT TCA

AGU

Diffusion

AKA Passive transport. Net movement of particles from an area of high concentration to an area of low concentration - considered passive as no energy is needed

Cell Autonomous

Action within or by a single cell, not requiring any other cells.

Plasma Membrane

All cells have this component; it encloses all of the contents of the entire cell.

Organism

All living things can be considered organisms.

Emergent Properties

All of the parts of an organism with different parts that do different things, put together to create a whole new operation.

Biosphere

All places on earth where organisms exist.

Death cap mushrooms produce a substance called alpha amanitin. Alpha amanitin efficiently blocks synthesis of mRNA, but not of tRNA or rRNA in eukaryotic organisms. How is that possible? Alpha amanitin efficiently interferes with RNA polymerase III, but not RNA polymerase I and II. Alpha amanitin efficiently blocks the action of one or more basic transcription factors. Alpha amanitin efficiently interferes with the action of RNA polymerase II, but not RNA polymerase I or III. Alpha amanitin efficiently interferes with the action of RNA polymerase I, but not RNA polymerase II or III.

Alpha-amanitin efficiently interferes with the action of RNA polymerase II, but not RNA polymerase I or III.

Cyclin Dependant Kinase

Also known as Cdk - it is the catalytic subunit that transfers the phosphate from ATP to certain AAs on target proteins - It is not active unless it is bound to it's "partner"

Transcription Factor II D

Also known as TFIID - a cofactor that distorts the helix of the DNA molecules, allowing for other factors (TFIIA, B, C, etc.) to pile on

Antibody

An antigen-binding immunoglobulin, produced by B cells, that functions as the effector in an immune response; stick to other proteins.

Holoenzyme

An enzyme consisting of a combination of a protein and one or more cofactors

Wobble Hypothesis

An idea proposed by Francis Crick that states the anticodon of tRNAs can still bind successfully to a codon whose third position requires a nonstandard base pairing. This explains how one tRNA is able to base pair with more than one type of codon

Lariat

An intermediate in RNA splicing in which a circular structure with a tail is created by a 5' to 3' bond

Light Microscope

An optical instrument with lenses that refract (bend) visible light to magnify images of LIVE specimens.

Genomics

Analyzing DNA sequences

Human

Aneuploidy is a _________ problem, not a mammalian problem

Which of the following statements about apoptosis is true? (a) Cells that constitutively express Bcl2 will be more prone to undergo apoptosis. (b) The prodomain of procaspases contains the catalytic activity necessary for procaspase activation. (c) Bax and Bak promote apoptosis by binding to procaspases in the apoptosome. (d) Apoptosis is promoted by the release of cytochrome c into the cytosol from mitochondria.

Apoptosis is promoted by the release of cytochrome c into the cytosol from mitochondria.

Community

Assemblage of populations of different species.

During the elongation phase of translation, individual tRNAs move through the three sites of the ribosome in which of the following sequences? A→P→E E→P→A P→E→A P→A→E

A→P→E

An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function? A) transporting ions against an electrochemical gradient B) cell-cell recognition C) maintaining fluidity of the phospholipid bilayer D) attaching to the cytoskeleton E) establishing the diffusion barrier to charged molecules

Based on Figure 7.19 in your textbook which of these experimental treatments would increase the rate of sucrose transport into the cell A) decreasing extracellular sucrose concentration B) decreasing extracellular pH C) decreasing cytoplasmic pH D) adding an inhibitor that blocks the regeneration of ATP E) adding a substance that makes the membrane more permeable to hydrogen ions

Cystic fibrosis is a genetic disease in humans in which chloride ion channels in cell membranes are missing or non-functional. Which of the following would you expect to be a problem for someone with nonfunctional chloride channeling? A) inadequate secretion of mucus B) buildup of excessive secretions in organs such as lungs C) buildup of excessive secretions in glands such as the pancreas D) sweat that includes no NaCl E) mental retardation due to low salt levels in brain tissue

In what way do the membranes of a eukaryotic cell vary? A) Phospholipids are found only in certain membranes. B) Certain proteins are unique to each membrane. C) Only certain membranes of the cell are selectively permeable. D) Only certain membranes are constructed from amphipathic molecules. E) Some membranes have hydrophobic surfaces exposed to the cytoplasm while others have hydrophilic surfaces facing the cytoplasm.

In which of the following would there be the greatest need for osmoregulation? A) an animal connective tissue cell bathed in isotonic body fluid B) a terrestrial animal such as a snake C) a red blood cell surrounded by plasma D) a lymphocyte before it has been taken back into lymph fluid E) a plant being grown hydroponically (in a watery mixture of designated nutrients)

The formulation of a model for a structure or for a process serves which of the following purposes? A) It asks a scientific question. B) It functions as a testable hypothesis. C) It records observations. D) It serves as a data point among results. E) It can only be arrived at after years of experimentation.

The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl) and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially the volume in both arms is the same. See figure 7.3.At the beginning of the experiment A) side A is hypertonic to side B. B) side A is hypotonic to side B. C) side A is isotonic to side B. D) side A is hypertonic to side B with respect to glucose. E) side A is hypotonic to side B with respect to sodium chloride.

What kinds of molecules pass through a cell membrane most easily? A) large and hydrophobic B) small and hydrophobic C) large polar D) ionic E) monosaccharides such as glucose

Which of the following is a characteristic feature of a carrier protein in a plasma membrane? A) It is a peripheral membrane protein. B) It exhibits a specificity for a particular type of molecule. C) It requires the expenditure of cellular energy to function. D) It works against diffusion. E) It has few if any hydrophobic amino acids.

White blood cells engulf bacteria through what process? A) exocytosis B) phagocytosis C) pinocytosis D) osmosis E) receptor-mediated exocytosis

What determines which base is to be added to an RNA strand during transcription? The order of the chemical groups in the backbone of the RNA molecule Base pairing between the DNA template strand and the RNA nucleotides Base pairing between the two DNA strands The previous base

Base pairing between the DNA template strand and the RNA nucleotides

Which of the following statements about gap junctions is false? a. Gap junctions are made of connexons b. Molecules are up to 100 daltons in MW can move across gap junctions c. Because gap junctions do not allow ions to pass through, they are not used for electrically coupling cells. d. Gap junctions can close in response to EC signals

Because gap junctions do not allow ions to pass through, they are not used for electrically coupling cells.

Which statement is correct concerning the function(s) of the 5' cap and the 3' poly(A) tail of eukaryotic mRNAs? The 5' cap serves as a recognition signal for the translational machinery but plays no role in stabilizing mRNA. Neither structure has any known function. The poly(A) tail stabilizes the mRNA, but plays no direct role in its translation to protein. Both structures serve as recognition signals for the translational machinery and extend the life span of the mRNA.

Both structures serve as recognition signals for the translational machinery and extend the life span of the mRNA.

Carbohydrates

Broken down to simple sugars

According to the fluid mosaic model of membrane structure proteins of the membrane are mostly A) spread in a continuous layer over the inner and outer surfaces of the membrane. B) confined to the hydrophobic core of the membrane. C) embedded in a lipid bilayer. D) randomly oriented in the membrane with no fixed inside-outside polarity. E) free to depart from the fluid membrane and dissolve in the surrounding solution.

Cell membranes are asymmetrical. Which of the following is a most likely explanation? A) The cell membrane forms a border between one cell and another in tightly packed tissues such as epithelium. B) Cell membranes communicate signals from one organism to another. C) Cell membrane proteins are determined as the membrane is being packaged in the ER and Golgi. D) The "innerness" and "outerness" of membrane surfaces are predetermined by genes. E) Proteins can only span cell membranes if they are hydrophobic.

Cystic fibrosis is a genetic disease in humans in which chloride ion channels in cell membranes are missing or non-functional. Chloride ion channels are membrane structures that include which of the following? A) gap junctions B) aquaporins C) hydrophilic proteins D) carbohydrates E) sodium ions

In order for a protein to be an integral membrane protein it would have to be which of the following? A) hydrophilic B) hydrophobic C) amphipathic D) completely covered with phospholipids E) exposed on only one surface of the membrane

In receptor-mediated endocytosis receptor molecules initially project to the outside of the cell. Where do they end up after endocytosis? A) on the outside of vesicles B) on the inside surface of the cell membrane C) on the inside surface of the vesicle D) on the outer surface of the nucleus E) on the ER

The sodium-potassium pump is called an electrogenic pump because it A) pumps equal quantities of Na+ and K+ across the membrane. B) pumps hydrogen ions out of the cell. C) contributes to the membrane potential. D) ionizes sodium and potassium atoms. E) is used to drive the transport of other molecules against a concentration gradient.

The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half filled with a solution of 2 M sucrose and 1 M glucose. Side B is half filled with 1 M sucrose and 2 M glucose. Initially the liquid levels on both sides are equal. See figure 7.2 A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids distilled water equal to the volume of blood lost is transferred directly into one of his veins. What will be the most probable result of this transfusion? A) It will have no unfavorable effect as long as the water is free of viruses and bacteria. B) The patient's red blood cells will shrivel up because the blood fluid is hypotonic compared to the cells. C) The patient's red blood cells will swell because the blood fluid is hypotonic compared to the cells. D) The patient's red blood cells will shrivel up because the blood fluid is hypertonic compared to the cells. E) The patient's red blood cells will burst because the blood fluid is hypertonic compared to the cells.

The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half filled with a solution of 2 M sucrose and 1 M glucose. Side B is half filled with 1 M sucrose and 2 M glucose. Initially the liquid levels on both sides are equal. See figure 7.2 Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are A) hypotonic to both fresh water and the salt solution. B) hypertonic to both fresh water and the salt solution. C) hypertonic to fresh water but hypotonic to the salt solution. D) hypotonic to fresh water but hypertonic to the salt solution. E) isotonic with fresh water but hypotonic to the salt solution.

What is the voltage across a membrane called? A) water potential B) chemical gradient C) membrane potential D) osmotic potential E) electrochemical gradient

Which of the following is true of integral membrane proteins? A) They lack tertiary structure. B) They are loosely bound to the surface of the bilayer. C) They are usually transmembrane proteins. D) They are not mobile within the bilayer. E) They serve only a structural role in membranes.

Which of the following membrane activities require energy from ATP hydrolysis? A) facilitated diffusion. B) movement of water into a cell C) Na+ ions moving out of the cell D) movement of glucose molecules E) movement of water into a paramecium

Which of the following statements is correct about diffusion? A) It is very rapid over long distances. B) It requires an expenditure of energy by the cell. C) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. D) It is an active process in which molecules move from a region of lower concentration to one of higher concentration. E) It requires integral proteins in the cell membrane.

Which of the following types of molecules are the major structural components of the cell membrane? A) phospholipids and cellulose B) nucleic acids and proteins C) phospholipids and proteins D) proteins and cellulose E) glycoproteins and cholesterol

Which of these are not embedded in the lipid bilayer at all? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins

Why are lipids and proteins free to move laterally in membranes? A) The interior of the membrane is filled with liquid water. B) There are no covalent bonds between lipid and protein in the membrane. C) Hydrophilic portions of the lipids are in the interior of the membrane. D) There are only weak hydrophobic interactions in the interior of the membrane. E) Molecules such as cellulose can pull them in various directions.

Cyclin

CDK complexes are composed of a regulatory subunit CDK and a catalytic subunit, cyclin. - FALSE

The G1 DNA damage checkpoint ________________. (a) causes cells to proceed through S phase more quickly (b) involves the degradation of p53 (c) is activated by errors caused during DNA replication (d) involves the inhibition of cyclin

Cdk complexes by p21 - involves the inhibition of cyclin-Cdk complexes by p21

Which of the following statements is false? a. Mitotic Cdk must be phosphorylated by an activating kinase (Cak) before it is active b. Phosphorylation of mitotic Cdk by the inhibitory kinase (Wee1) makes Cdk inactive, even if it is phosphorylated by the activating kinase. c. Active M

Cdk phosphorylates the activating phosphatase (Cdc25) in a positive feedback loop. d. The activating phosphatase (Cdc25) removes all phosphates from mitotic Cdk so that M-Cdk will be active. - The activating phosphatase (Cdc25) removes all phosphates from mitotic Cdk so that M-Cdk will be active.

Which of the following statements is false? a. DNA synthesis begins at the origin of replication b. Loading of the origin recognition complexes (ORCs) is triggered by S

Cdk. c. Phosphorylation & degradation of Cdc6 help to ensure that DNA is replicated only once in each cell cycle. d. DNA synthesis can only begin after pre-replicative complexes assembles on the ORCs - The loading of the origin recognition complexes (ORCs) is triggered by S-Cdk.

You create cells with a version of Cdc6 that cannot be phosphorylated and thus cannot be degraded. Which of the following statements describes the likely consequence of this change in Cdc6? (a) Cells will enter S phase prematurely. (b) Cells will be unable to complete DNA synthesis. (c) The origin recognition complex (ORC) will be unable to bind to DNA. (d) Cdc6 will be produced inappropriately during M phase.

Cells will be unable to complete DNA synthesis.

Adaptation

Changes that occur over time due to the environment of the species.

Post-Translational Modifications

Chemical modifications of protein structure - generally involves the addition of functional groups/small molecules to proteins. This includes: glycosylation, and phosphorylation

Homologous

Chromosomes that are each taken from the parent

Exons

Coding sequences in a eukaryotic mRNA transcript

Codons are three base sequences that specify the addition of a single amino acid. How do eukaryotic codons and prokaryotic codons compare? Codons are a nearly universal language among all organisms. The translation of codons is mediated by tRNAs in eukaryotes, but translation requires no intermediate molecules such as tRNAs in prokaryotes. Prokaryotic codons usually contain different bases than those of eukaryotes. Prokaryotic codons usually specify different amino acids than those of eukaryotes.

Codons are a nearly universal language among all organisms.

Organs

Composed of 2 or more types of tissue.

mRNA

Contain the information to make proteins.

After a membrane freezes and then thaws it often becomes leaky to solutes. The most reasonable explanation for this is that A) transport proteins become nonfunctional during freezing. B) the lipid bilayer loses its fluidity when it freezes. C) aquaporins can no longer function after freezing. D) the integrity of the lipid bilayer is broken when the membrane freezes. E) the solubility of most solutes in the cytoplasm decreases on freezing.

An organism with a cell wall would have the most difficulty doing which process? A) diffusion B) osmosis C) active transport D) phagocytosis E) facilitated diffusion

Cystic fibrosis is a genetic disease in humans in which chloride ion channels in cell membranes are missing or non-functional. If a young male child has cystic fibrosis which of the following would affect his fertility? A) inability to make sperm B) incomplete maturation of the testes C) failure to form genital structures appropriately D) incorrect concentrations of ions in semen E) abnormal pH in seminal fluid

In the years since the proposal of the fluid mosaic model of the cell membrane which of the following observations has been added to the model? A) The membrane is only fluid across a very narrow temperature range. B) Proteins rarely move even though they possibly can do so. C) Unsaturated lipids are excluded from the membranes. D) The concentration of protein molecules is now known to be much higher. E) The proteins are known to be made of only acidic amino acids.

Ions diffuse across membranes down their A) chemical gradients. B) concentration gradients. C) electrical gradients. D) electrochemical gradients. E) A and B are correct.

Proton pumps are used in various ways by members of every kingdom of organisms. What does this most probably mean? A) Proton pumps must have evolved before any living organisms were present on the earth. B) Proton pumps are fundamental to all cell types. C) The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism. D) Cells with proton pumps were maintained in each Kingdom by natural selection. E) Proton pumps are necessary to all cell membranes.

The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl) and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially the volume in both arms is the same. See figure 7.3.If you examine side A after 3 days you should find A) a decrease in the concentration of NaCl and glucose and an increase in the water level. B) a decrease in the concentration of NaCl an increase in water level and no change in the concentration of glucose. C) no net change in the system.D) a decrease in the concentration of NaCl and a decrease in the water level. E) no change in the concentration of NaCl and glucose and an increase in the water level.

When a membrane is freeze-fractured the bilayer splits down the middle between the two layers of phospholipids. In an electron micrograph of a freeze-fractured membrane the bumps seen on the fractured surface of the membrane are A) peripheral proteins. B) phospholipids. C) carbohydrates. D) integral proteins. E) cholesterol molecules.

Which of the following is true of the evolution of cell membranes? A) Cell membranes have stopped evolving now that they are fluid mosaics. B) Cell membranes cannot evolve if proteins do not. C) The evolution of cell membranes is driven by the evolution of glycoproteins and glycolipids. D) As populations of organisms evolve different properties of their cell membranes are selected for or against. E) An individual organism selects its preferred type of cell membrane for particular functions.

Which of the following processes includes all others? A) osmosis B) diffusion of a solute across a membrane C) facilitated diffusion D) passive transport E) transport of an ion down its electrochemical gradient

Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells? A) The animal cell is in a hypotonic solution and the plant cell is in an isotonic solution. B) The animal cell is in an isotonic solution and the plant cell is in a hypertonic solution. C) The animal cell is in a hypertonic solution and the plant cell is in an isotonic solution. D) The animal cell is in an isotonic solution and the plant cell is in a hypotonic solution. E) The animal cell is in a hypertonic solution and the plant cell is in a hypotonic solution.

Which of these are attached to the extracellular matrix? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins

Who proposed that the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids? A) H. Davson and J. Danielli B) I. Langmuir C) C. Overton D) S. Singer and G. Nicolson E) E. Gorter and F. Grendel

You are working on a team that is designing a new drug. In order for this drug to work it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule enters the cell? A) blood or tissue type of the patient B) non-polarity of the drug molecule C) lack of charge on the drug molecule D) similarity of the drug molecule to other molecules transported by the target cells E) lipid composition of the target cells' plasma membrane

Neucleic Acids

DNA and RNA

Higher Order Structure

DNA molecules in eukaryotic cells develop _______ _________ ________ as it allows for compact packaging and strict regulation of gene expression.

Meiosis

Division of genetic material to produce daughter cells with half the hereditary material found in the parent cell

Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine however rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information which transport mechanism is most probably functioning in the intestinal cells? A) simple diffusion B) phagocytosis C) active transport pumps D) exocytosis E) facilitated diffusion

If a membrane protein in an animal cell is involved in the cotransport of glucose and sodium ions into the cell which of the following is most likely true? A) The sodium ions are moving down their electrochemical gradient while glucose is moving up. B) Glucose is entering the cell along its concentration gradient. C) Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell. D) Potassium ions move across the same gradient as sodium ions. E) A substance that blocked sodium ions from binding to the cotransport protein would also block the transport of glucose.

Of the following functions which is most important for the glycoproteins and glycolipids of animal cell membranes? A) facilitated diffusion of molecules down their concentration gradients B) active transport of molecules against their concentration gradients C) maintaining the integrity of a fluid mosaic membrane D) maintaining membrane fluidity at low temperatures E) a cell's ability to distinguish one type of neighboring cell from another

Several seriously epidemic viral diseases of earlier centuries were then incurable because they resulted in severe dehydration due to vomiting and diarrhea. Today they are usually not fatal because we have developed which of the following? A) antiviral medications that are efficient and work well with all viruses B) antibiotics against the viruses in question C) intravenous feeding techniques D) medication to prevent blood loss E) hydrating drinks that include high concentrations of salts and glucose

Water passes quickly through cell membranes because A) the bilayer is hydrophilic. B) it moves through hydrophobic channels. C) water movement is tied to ATP hydrolysis. D) it is a small polar charged molecule. E) it moves through aquaporins in the membrane.

What are the membrane structures that function in active transport? A) peripheral proteins B) carbohydrates C) cholesterol D) cytoskeleton filaments E) integral proteins

What mechanisms do plants use to load sucrose produced by photosynthesis into specialized cells in the veins of leaves? A) an electrogenic pump B) a proton pump C) a contransport protein D) A and C only E) A B and C

When a plant cell such as one from a peony stem is submerged in a very hypotonic solution what is likely to occur? A) the cell will burst B) the cell membrane will lyse C) plasmolysis will shrink the interior D) the cell will become flaccid E) the cell will become turgid

When biological membranes are frozen and then fractured they tend to break along the middle of the bilayer. The best explanation for this is that A) the integral membrane proteins are not strong enough to hold the bilayer together. B) water that is present in the middle of the bilayer freezes and is easily fractured. C) hydrophilic interactions between the opposite membrane surfaces are destroyed on freezing. D) the carbon-carbon bonds of the phospholipid tails are easily broken. E) the hydrophobic interactions that hold the membrane together are weakest at this point

Which of these often serve as receptors or cell recognition molecules on cell surfaces? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins

Who was/were the first to propose that cell membranes are phospholipid bilayers? A) H. Davson and J. Danielli B) I. Langmuir C) C. Overton D) S. Singer and G. Nicolson E) E. Gorter and F. Grendel

How do reproductive cloning and therapeutic cloning differ? (a) The DNA in the nucleus of cells produced for therapeutic cloning is genetically identical to the donor genome, whereas in cells produced for reproductive cloning it is not. (b) Reproductive cloning requires a supply of fertilized donor egg cells, whereas therapeutic cloning requires unfertilized egg cells. (c) Therapeutic cloning requires nuclear transplantation, whereas reproductive cloning does not. (d) Embryos are placed into foster mothers during reproductive cloning but not during therapeutic cloning.

Embryos are placed into foster mothers during reproductive cloning but not during therapeutic cloning.

Cytokinesis

End of the cell cycle where the cytoplasm is divided into 2 by a contractile ring of actin/myosin filaments, creating two daughter cells

Lipids

Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen; non polar structures

Flippase

Enzyme that moves specific phospholipids (PS, PE) from cytosolic to non-cytosolic leaflet; used for the membrane assembly and is done by the Golgi apparatus

Scramblases

Enzyme that transfers random phospholipids to other leaflets; used for membrane assembly and is done by the Endoplasmic reticulum

refer to question 20-4. Why do you suppose these two different cell types attach differently to the extracellular matrix?

Epithelial cells need stability and fibroblast need movement. forces for pulling on the matrix or for driving crawling movement are generated by the actin cytoskeleton. In mature epithelium, focal contact sites are presumably less prominent because the cells are largely fixed in place and have no need to crawl over the basal lamina or actively pull on it.

RNA Polymerase I

Eukaryotic RNA Polymerase that codes for: most rRNA genes

RNA Polymerase II

Eukaryotic RNA Polymerase that codes for: protein coding genes

RNA Polymerase III

Eukaryotic RNA Polymerase that codes for: tRNA genes and genes for other small RNAs

A loss of cdc2 function results in the premature entry into mitosis.

FALSE

Checkpoint mechanisms can determine whether DNA has been properly regulated but whether DNA is segregated to the daughter cells.

FALSE

Fibronectin is a multidomain extracellular matrix protein that forms the core of a proteoglycan aggregate.

FALSE

Unlike proteins, polysaccharide gels can not resist compression.

FALSE CAN!!!

The maturation promoting factor stimulates meiotic maturation in oocytes and in doing so inhibits mitosis in somatic cells.

FALSE DRIVES MITOSIS IN SOMATIC CELLS

Cells grow in size and synthesize proteins and RNA at the interface of G2/M period of the cell cycle.

FALSE interphase

Animal Epithelial Cells Consist Largely of Extracellular Matrix.

FALSE ANIMAL CONNECTIVE TISSUE

True or false. A tRNA with an anticodon complementary to the stop codon catalyzes the reaction by which translation is terminated. True False

False

Final phase of interphase. The cell completes their preparation for mitosis; chromosomes condense, adn the spindles form

First stage in interphase where most of the cell's growth takes place

Which of these correctly illustrates the pairing of DNA and RNA nucleotides? GTTACG CAATCG GTTACG CAAUGC GTTACG GTTACG GTTACG ACCGTA GTTACG UAACAU

GTTACG CAAUGC

Which of the following tRNA anticodons could decode the mRNA codon CAG (recall that codons are always written in the 5'→3' direction and anticodons are written in the 3'→5' direction)? CUG only GUU or GUC GUC only CUG or GUC

GUU or GUC

Aneuploidy

Gametes with abnormal number of chromosomes

Proteins

Genes contain instructions for assembling, amino acid polymers.

Horizontal Gene Transfer

Genes transferred by different species.

Which organelle fragments during mitosis?

Golgi apparatus

Population

Group of organisms of same species that occupy same environment.

Taxonomy

Grouping of different species

Extracellular Proteins

Hold cells together in tissue.

Cytochrome C

Important molecule, usually part of the electron transport chain, that is used for the triggering of apoptosis

Non-Disjunction

Improper distribution of chromosomes to each daughter cell

Which of the following statements is true? a. Anaphse A must be completed before anaphse B can take place b. In cells which anaphse B predominates, the spindle will elongate much less than in cells in which anaphse A dominates c. In anaphse A, both kinetochore & interpolar MTs shorten. d In anaphase B, microtubules associated w cell cortex shorten

In anaphase B, microtubules associated with the cell cortex shorten.

Which of the following statements about integrins is false? a. Integrins use adaptor proteins to interact with the microtubule cytoskeleton b. Integrins can switch to an activated state by binding to an ECM matrix molecule c. Integrins can switch to an activated state by binding to an intracellular protein d. Activated integrin molecules takes on an extended conformation

Integrins use adaptor proteins to interact with the microtubule cytoskeleton.

Ecosystem

Interactions of a community with its physical environment.

Refer to the figure. What is the function of the ACC sequence at the 3' end? It stabilizes the tRNA amino acid complex. It is the active site of this ribozyme. It base pairs with the codon of mRNA. It attaches to the amino acid.

It attaches to the amino acid.

Refer to the figure. What is the function of the AGU on the loop of the tRNA? It attaches to the amino acid. It stabilizes the tRNA amino acid complex. It is the active site of this ribozyme. It base pairs with the codon of mRNA.

It base pairs with the codon of mRNA.

What happens to RNA polymerase II after it has completed transcription of a gene? It is free to bind to another promoter and begin transcription. It joins with another RNA polymerase to carry out transcription. It is degraded. It begins transcribing the next gene on the chromosome.

It is free to bind to another promoter and begin transcription.

Kind of a stage in the Cell cycle; A point at which the cell is currently not going through the cycle

Which of the following statements about kinetochores is true?

Kinetochores assemble onto chromosomes during late prophase.

Eukarya

Larger cells with internal compartments that serve various functions.

Vertical Evolution

Lineage changes from ancestors, from the same family.

Cholesterol

Lipid that are in animal cells which make the membrane more stiffer and less fluid

Centromere

Location where the splitting occurs

Mitosis Promoting Factor

MPF for short - A complex of a cyclin and cyclin-dependent kinase that phosphorylates a number of specific proteins needed to initiate mitosis in eukaryotic cells.

Molecules

Made up of atoms. Many molecules are called polymers such as a polypeptide.

Tissues

Many cells of the same type to form multi-cellular organisms.

Variability

Meiosis and sexual reproduction create offspring with genetic ____________

Electron Microscope

Microscope that forms an image by focusing beams of electrons onto a DEAD specimen.

Cells

Molecules and macromolecules form together to form membranes.

Sodium-Potassium ATPase

Molecules that moves sodium ions out and potassium ions in. This is coupled with the hydrolysis of ATP. Conformational shape change is caused by the addition of a phosphate group onto the molecule.

Which of the following statements is false? a. Cytokinesis in plant cells is mediated by the microtubule cytoskeleton. b. Small membrane vesicles derived from the Golgi apparatus deliver new cell wall material for the new wall of the dividing cell. c.The phragmoplast forms from the remains of interpolar microtubules of the mitotic spindle. d. Motor proteins walking along the cytoskeleton are important for the contractile ring that guides formation of the new cell wall.

Motor proteins walking along the cytoskeleton are important for the contractile ring that guides formation of the new cell wall.

Oncogene

Mutated versions of normal genes/proteins that are involved in driving cell division/proliferation

Introns

Non-coding sequences in a eukaryotic mRNA transcript

Proto-oncogene

Non-mutated version of the normal genes

After transcription begins, several steps must be completed before the fully processed mRNA is ready to be used as a template for protein synthesis on the ribosomes. Which three statements correctly describe the processing that takes place before a mature mRNA exits the nucleus? A translation stop codon is added at the 3' end of the pre mRNA. Noncoding sequences called introns are spliced out by molecular complexes called spliceosomes. A cap consisting of a modified guanine nucleotide is added to the 5' end of the pre mRNA. Coding sequences called exons are spliced out by ribosomes. A poly A tail (50 250 adenine nucleotides) is added to the 3' end of the pre mRNA.

Noncoding sequences called introns are spliced out by molecular complexes called spliceosomes. A cap consisting of a modified guanine nucleotide is added to the 5' end of the pre-mRNA. A poly-A tail (50-250 adenine nucleotides) is added to the 3' end of the pre-mRNA.

Which one of the following, if missing, would prevent transcription from starting? 5' cap poly A tail AUG codon exon None of the above.

None of the above.

Number of pairs of autosomes that are in the body

Number of pairs of sex chromosomes that are in the body

Which of the following statements about the cell cycle is false? a. Once a cell decides to enter the cell cycle, the time from start to finish is the same in all eucaryotic cells. b. An unfavorable environment can cause cells to arrest in G1 c. A cell has more DNA during G2 than it did in G1 d. Cleavage divisions that occur in an early embryo have short G1 & G2

Once a cell decides to enter the cell cycle, the time from start to finish is the same in all eucaryotic cells.

Transport Solutes

One of the functions of membranes is the fact that they ________ ______ and exchange molecules across the membrane.

Cell Cycle

Orderly sequence of events in which a cell duplicates it's contents and divides into two

DNA does not store the information to synthesize which of the following? Proteins Messenger RNA DNA Organelles

Organelles

Model Organisms

Organisms studied by many scientists in order to create new over all conclusions about life.

Synapsis

Pairing of the chromosomes, resulting in tetrads/bivalents

Phase of the cell cycle where Mitosis and cytokinesis occur

Which of the following processes is an example of a post translational modification? Peptide bond formation Initiation Elongation Phosphorylation

Phosphorylation

Amphipathic

Possess both hydrophilic properties as well as hydrophobic traits

Tugor Pressure

Pressure of the cell contents against the cell wall in plant and bacterial cells - its state is considered normal for plant cells

Transcription

Process in which DNA is used as a template for the production of complementary messenger RNA molecules

Translation

Process in which a ribosome assembles amino acids in a specific sequence to synthesize a specific polypeptide chain by messenger RNA

Apoptosis

Programmed cell death - proteolytic cascade carried out by the caspase family of enzymes

Polycistronic

Prokaryotes have ____ mRNA which has many genes in a single transcript.

Bacteria and Archaea

Prokaryotic cells; simple cell structures

Kinetochore

Protein plaque that attaches to the spindle

Rudder

Protein that directs where to go on the DNA

Zipper

Protein that opens up the DNA strand

TATA Binding Protein

Protein that recognizes the promoter sequence

Polyribosomes

Proteins can take long to synthesize if only one or two is used. Lots of ribosomes are used, and all of them are called _______________

Enzyme

Proteins function as enzymes to synthesize and break down cellular molecules and macro-molecules.

Cytoskeleton

Proteins involved in cell shape and movement.

Cell Signaling

Proteins needed for cell signaling with other cells and with the environment.

Cell Organism

Proteins organize components with in cells.

Transport Proteins

Proteins that facilitate the uptake and export of substances.

Which of the following statements is false? a. Proteoglycans can act as filters to regulate which molecules pass thorugh EC medium b. Negative charge associated w proteoglycans attracts cations, which cause water to be sucked into ECM c. Proteoglycans are a major component of compact connective tissues but are relatively unimportant in watery tissues such as the jellylike substance in the interior of the eye. d. Glycosaminoglycans are components of proteoglycan

Proteoglycans are a major component of compact connective tissues but are relatively unimportant in watery tissues such as the jellylike substance in the interior of the eye.

Which of the following statements about animal connective tissues is true? (a) Enzymes embedded in the plasma membrane synthesize the collagen in the extracellular matrix extracellularly. (b) In connective tissue, the intermediate filaments within the cells are important for carrying the mechanical load. (c) Cells can attach to a collagen matrix by using fibronectin, an integral membrane protein. (d) Proteoglycans can resist compression in the extracellular matrix.

Proteoglycans can resist compression in the extracellular matrix.

Ribozyme

RNA molecule with a well defined tertiary structure that enables it to catalyze a chemical reaction

Splicing

Removal of introns. This occurs after capping, and while the RNA is still being transcribed.

Sister Chromatids

Replicated homologs

Dynamic Equilibrium

Result of diffusion where there is continuous movement of particles but no overall change in concentration

Why are ribonucleotide triphosphates, rather than ribonucleotides (which have one phosphate group), the monomers required for RNA synthesis in cells? Only ribonucleotide triphosphates contain the sugar ribose. Ribonucleotides cannot form complementary base pairs with the DNA template. Ribonucleotide triphosphates have low potential energy, making the polymerization reaction endergonic. Ribonucleotide triphosphates have high potential energy, making the polymerization reaction exergonic.

Ribonucleotide triphosphates have high potential energy, making the polymerization reaction exergonic.

Where does translation take place? Golgi apparatus Ribosome Nucleus Endoplasmic reticulum

Ribosome

Second phase of interphase; The DNA is copied, and as well, the chromosomes are attached at the centromeres

Frameshift Mutation

Shifting the reading frame of the codons

Atoms

Smallest unit of an element that has chemical properties of the element.

Electro-Chemical Gradient

Specific type of chemical gradient that describes the different charges

Spliceosomes

Splicing is carried out by these molecules. They consist of small nuclear ribonucleic particles (snRNPs)

Metaphase

Stage in mitosis where the chromosomes are aligned at the equator of the spindle, between the spindle poles. The microtubules are attached onto both sides of the kinetochore

Prometaphase

Stage in mitosis where the nuclear envelope breaks down and the chromosome attach onto the spindle microtubules via kinetochores and undergo active movement

Telophase

Stage in mitosis where the nuclear envelope starts to reform as it arrives to the poles; a contractile ring starts to form

Anaphase

Stage in mitosis where the sister chromatids synchronously separate, and each is pulled slowly toward the spindle pole it is attached to - the microtubules get shorter, and the spindle poles move farther apart

Scientific Method

Standardized approach for scientist to use when doing experiments and research.

Genetics

Study effect of mutations.

Cell Biology

Study interactions of macro-molecules with respect to specific structures and locations.

Proteomes

Study of all proteins an organism makes.

Length

The ____ of the cell cycle depends on the cell type, developmental stage, external signals, etc.

A Site

The acceptor site on a ribosome for an aminoacyl tRNA

Poly A tail

The addition of a polyadenine tail is also known as the ______ __ _____. This protects from degradation.

Methionine

The amino acid that initiates translation. It's codon is AUG.

Interphase

The cell spends almost 90% of their time in this phase; The cells grow by producing proteins, organelles, copies it's chromosomes, and prepares for cell division

Which of the following descriptions is consistent with the behavior of a cell that lacks a protein required for a checkpoint mechanism that operates in G2? a. The cell would be unable to enter M phase. b. The cell would be unable to enter G2. c. The cell would enter M phase under conditions when normal cells would not. d. The cell would pass through M phase more slowly than normal cells.

The cell would enter M phase under conditions when normal cells would not.

What would be the most obvious outcome of repeated cell cycles consisting of S phase and M phase only? a. Cells would not be able to replicate their DNA. b. The mitotic spindle could not assemble. c. Cells would get larger and larger. d. The cells produced would get smaller and smaller.

The cells produced would get smaller and smaller.

Which of the following statements is false? a. The cleavage furrow is a puckering of the plasma membrane caused by the constriction of a ring of filaments attached to the plasma membrane. b. The cleavage furrow will not begin to form in the absence of a mitotic spindle. c. The cleavage furrow always forms perpendicular to the interpolar microtubules. d. The cleavage furrow always forms in the middle of the cell.

The cleavage furrow always forms in the middle of the cell.

Potential Energy

The energy stored, relative to a certain position. In terms of biological membranes, this is the potential energy created by a high concentration gradient

Core enzyme

The enzyme responsible for catalysis in a multi-part holoenzyme. Specifically, it has the ability to synthesize RNA.

Osmoconformers

The fact that most marine organisms adjust their internal salt concentrations to match the seawater is an example of _________________.

some have speculated that Abraham Lincoln had Marfan Syndrome. What protein is mutated? What about President Lincoln may have caused these speculations?

The fibrillin-1 protein on chromosome 15. President Lincoln was speculated to have this syndrome because he was so tall.

Outside

The hydrophobic R-groups are usually positioned on the ________ of the protein in order to interact with the hydrophobic plasma membrane.

Which of the following steps occurs last in the initiation phase of translation? A peptide bond is formed between two adjacent amino acids. The large ribosomal subunit joins the complex. An aminoacyl tRNA binds to the start codon. The small subunit of the ribosome binds to the 5' cap on the mRNA.

The large ribosomal subunit joins the complex.

Membrane Fluidity

The measure of how easily lipid molecules move within a membrane leaflet

Which of the following statements about plant cell walls is true? a. MT cytoskeleton directs the orientation in which cellulose is deposited in the cell wall b. Molecular components of cell wall are the same in all plant tissues c. Bc plant cell walls are rigid, they are not deposited until cell has stopped growing d. Cellulose in cell walls is produced as precursor molecule in the cell & delivered to extracellular space by exocytosis

The microtubule cytoskeleton directs the orientation in which cellulose is deposited in the cell wall.

Which of the following statements is true? (a) The mitotic spindle is largely made of intermediate filaments. (b) The contractile ring is made largely of microtubules and actin filaments. (c) The contractile ring divides the nucleus in two. (d) The mitotic spindle helps segregate the chromosomes to the two daughter cells.

The mitotic spindle helps segregate the chromosomes to the two daughter cells.

Coupled Transport

The movement of a substance against its electrochemical gradient (from lower to higher concentration, or from opposite charge to like charge) using the energy provided by the simultaneous movement of a different chemical down its electrochemical gradient.

Which of the following events does not usually occur during interphase? a. Cells grow in size b. Nuclear envelope breaks down c. DNA is replicated d. Centrosomes are duplicated

The nuclear envelope breaks down.

The number of pairs of chromosomes in a human cell

Non-template (coding) strand

The other DNA strand that is not being transcribed. The sequence of this DNA strand matches the RNA strand, except for the uracil instead of thymine

Which of the following statements best describes the promoter of a protein coding gene? The promoter is a site at which only RNA polymerase will bind. The promoter is part of the RNA molecule itself. The promoter is a site found on RNA polymerase. The promoter is a nontranscribed region of a gene.

The promoter is a nontranscribed region of a gene.

Exon Junction Complex

The protein complex that is binded onto properly spliced mRNAs to allow for exit into the cytosol

Sigma Factor

The regulatory subunit part of the holoenzyme

What is meant by translocation? The two ribosomal subunits are joined in a complex. The completed polypeptide is released from the ribosome. The polypeptide chain grows by one amino acid. The ribosome slides one codon down the mRNA.

The ribosome slides one codon down the mRNA.

E Site

The site on a ribosome where tRNAs that no longer bind to an amino acid exit the ribosome

P Site

The site on a ribosome where the peptide bond forms that adds an amino acid to the growing polypeptide chain

Template Strand

The strand that is being transcribed

Natural Selection

The strongest of the species live, weeding out the weak and creating new species with the most beneficial features.

Transition Temperature

The temperature at which the membrane starts to "gel" or solidify

Cell Theory

The theory that cells form the fundamental structural and functional units of all living organisms.

cells in the stem of a seedling that is grown in the dark orient their microtubules horizontally. How would you expect this to affect the growth of the plant?

The turgor pressure allows the growth through the surface. The horizontal orientation of the microtubules will be associated with horizontal orientation of cellulose microfibils deposited in the cell walls. the growth of the cell wall will be in a vertical direction, expanding the distance between cellulose microfibrils without stretching them.

How are RNA hairpin turns related to termination? The hairpin turn prevents more nucleoside triphosphates from entering the active site of the enzymes, effectively shutting off the process of polymerization. Release factors bind to sites on the hairpin turn, causing release of the RNA transcript. A three base repeat signals a stop sequence, and the RNA transcript is released. The turns are formed from complementary base pairing and cause separation of the RNA transcript and RNA polymerase.

The turns are formed from complementary base pairing and cause separation of the RNA transcript and RNA polymerase.

Ion Channels

These channels, when they are open, allow the movement, or conductance, of certain ions, such as Na+, K+, Ca+, and Cl- down their respective gradients

Prokaryotic Promoters

These sections are where prokaryotic transcription is initiated. They are regions on the non-template strand, and include the 10 box and 35 box.

David Pribnow studied the base sequences of promoters in bacteria and bacterial viruses. He found two conserved regions in these promoters (the 10 box and the 35 box). What is the function of these two regions of the promoter? They attach the correct nucleotide triphosphate to the template DNA strand. They bind the sigma subunit that is associated with RNA polymerase. They separate the two DNA strands. They signal the initiation site.

They bind the sigma subunit that is associated with RNA polymerase.

Human Red Blood Cells

This cell has the best understood plasma membrane, are very simple, and that is why they are considered the "model organisms" for the plasma membrane.

mRNA

This form of RNA acts as a intermediary between the DNA and the ribosomes. It is complementary from the template strand, and varies in length.

rRNA

This form of RNA binds with other proteins to form the ribosomes; these vary in length. Also catalyze protein synthesis

tRNA

This form of RNA serves as the delivery system of amino acids to ribosomes to synthesize proteins; is usually very short - 70-90 base pairs long

Hairpin

This type of structure is produced when the RNApol reaches a transcription termination signal in the DNA template. This structure disrupts the transcription complex, and the RNApol separates from the RNA transcript.

Active Transport

Transport of a solute across a membrane to a region of higher concentration from a region of low concentration; against concentration gradient; usually needs energy to do this

Facilitated Diffusion

Type if diffusion that goes with the concentration gradient, but uses carrier proteins to guide the solute in

S Cdk

Type of cyclin that carries out replication

G1/S Cdk

Type of cyclin that commits the cells to DNA replication

G1 Cdk

Type of cyclin that helps with the passage through the restriction point

M Cdk

Type of cyclin that promotes the events of mitosis (MPF)

GLUT1

Type of glucose transporter on mammalian cells; will move glucose but not fructose, and D-Glucose but not L-Glucose

RNA

Type of nucleic acid that is used for the translation and transcription of a new protein.

Integral

Type of protein that is embedded into the cell - these proteins are usually involved with transport

Voltage Gated

Type of regulation of channel activity that opens channels based on the voltage or electrochemical gradient

Asexual

Type of reproduction that allows an organism in a well adapted environment to clone itself

p53

Type of tumor supressor that detects DNA damage at G1/S checkpoint, which leads to the synthesis of the inhibitors of G1/S-Cdk and S-Cdk

Peripheral

Types of proteins that are more associated with the surface of the cell - usually, they are cell identity markers or receptor sites

Free Radicals

Unstable, highly-reactive molecules created during normal metabolism and in response to environmental factors; may play a role in the development of cancer, cardiovascular disease, and other diseases of aging by reacting with and damaging DNA and other parts of cells.

Transmission Microscope

Uses ultra-thin slices of cells that are stained.

proteaoglycans are characterized by the abundance of negative charges on their sugar chains. How would the properties of these molecules differ if the negative charges were not as abundant?

Water wouldn't absorb and it would be more compressible

Tugor

Way to maintain osmotic balance: Plants are hyper-osmotic to their environment, so water is pulled in, which presses the membrane out to the cell wall

Osmoregulators

Way to maintain osmotic balance: some single-celled organisms have contractile vacuoles that periodically pump out water

Isotonic

When a solution is _________, this means that the concentration of the solutes is equal to the concentration in the cell. No net loss or gain is recorded.

Hypertonic

When a solution is _________, this means that the concentration of the solutes is greater in the solution rather than in the cell. This causes the cell to shrink.

Hypotonic

When a solution is _________, this means that the concentration of the solutes is lower in the solution rather than in the cell. This causes the cell to swell and potentially burst.

resonance

a carbon chain can include a double bond; if on alternating carbon atoms, the bonding electrons move within the molecule stabilizing the structure

What could be the consequence of a mutation that changes the sequence of nucleotides in a promoter? a change in when the corresponding gene is transcribed a change in the amino acid sequence of the corresponding protein a change in the base sequence of the corresponding mRNA a change in the efficiency of translation of the corresponding mRNA

a change in when the corresponding gene is transcribed

eukaryote

a class of cell that does have a nucleus; three types include protists (single cell), animal and plant

prokaryote

a class of cell that does not have a nucleus; two types include bacteria and archae

During RNA processing a(n) _____ is added to the 3' end of the RNA. 3' untranslated region a long string of adenine nucleotides 5' untranslated region coding segment modified guanine nucleotide

a long string of adenine nucleotides

pKa

a measure of proton binding affinity

Scanning Microscope

a microscope that produces an enlarged, three-dimensional image of an object by using a beam of electrons rather than light.

(eu)bacteria

a prokaryotic cell class that has a cell wall (except mycoplasma, the smallest)

archaebacteria

a prokaryotic cell class that has a cell wall and lives in extreme conditions (known as extremophiles: halophiles, acidophiles, thermophiles)

peptide

a string of amino acids (di-, tri-, tetra-, poly-)

Which of the following substances would you expect to spread from one cell to the next through (a) gap junctions and (b) plasmodesmata: glutamic acid, mRNA, cyclic AMP, Ca 2+, G proteins, and plasma membrane phospholipids?

a. glutamic acid, cyclic AMP, Ca2+ b. glutamic acid, cyclic AMP, Ca2+, plasma membrane phospholipids

acetylglucosamine is a repeating disaccharide found in the extracellular matrix. - true

anchoring junction that connects actin filaments in one cell to those in the next cell

adherens junction

Which type of junction involves a connection to the actin cytoskeleton? (a) adherens junctions (b) desmosomes (c) tight junctions (d) gap junctions

adherens junctions

cell theory

all organisms consist of one or more cells; the cell is basic unit of structure for all organisms; all cells arise from preexisting cells

Schleiden

all plant tissues are composed of cells

Proteoglycans in the extracellular matrix of animal tissues ________________. (a) chiefly provide tensile strength (b) allow cartilage to resist compression (c) are linked to microtubules through the plasma membrane (d) are polysaccharides composed of glucose subunits

allow cartilage to resist compression

building blocks of proteins

amino acids

When introduced into mitotic cells, which of the following is expected to impair anaphase B but not anaphase A? (a) an antibody against myosin (b) ATPγS, a nonhydrolyzable ATP analog that binds to and inhibits ATPases (c) an antibody against the motor proteins that move from the plus end of microtubules to the minus end (d) an antibody against the motor proteins that move from the minus end of microtubules toward the plus end

an antibody against the motor proteins that move from the minus end of microtubules toward the plus end

scientific fact

an attempt to state our best current understanding

Mitogen

any substance or agent that stimulates mitotic cell division.

the exposed free surface of an epithelial cell

apical surface

Induced pluripotent stem (iPS) cells ______________________. (a) are created by the expression of a set of key genes in cells derived from adult tissues so that these cells can differentiate into a variety of cell types (b) require a supply of donor egg cells, such as embryonic stem cells (c) can differentiate into a greater variety of adult tissues than embryonic stem cells (d) are created by nuclear transplantation

are created by the expression of a set of key genes in cells derived from adult tissues so that these cells can differentiate into a variety of cell types

Hemidesmosomes are important for ______________________. (a) tubulation of epithelial sheets (b) linkages to glycosaminoglycans (c) forming the basal lamina (d) attaching epithelial cells to the extracellular matrix

attaching epithelial cells to the extracellular matrix

a thin mat of extracellular matrix that separates epithelial sheets, and many other types of cells such as muscle or fat cells, from the connective tissue.

basal lamina

strands of cell biology

biochemistry; cytology; genetics

hydrolysis reaction

breaking the chain between monomers (water consumed)

Programmed cell death occurs ________________. (a) by means of an intracellular suicide program (b) rarely and selectively only during animal development (c) only in unhealthy or abnormal cells (d) only during embryonic development

by means of an intracellular suicide program

a member of a family of proteins that mediate Ca 2+ dependent cell-cell adhesion in animal tissues.

cadherin family of proteins

Adherens junctions ______________________. (a) can be used to bend epithelial sheets into tubes (b) are most often found at the basal surface of cells (c) are found only in adult tissues (d) involve fibronectin and integrin interactions

can be used to bend epithelial sheets into tubes

chloroplasts

capture energy from sunlight, convert to carbohydrate

Apoptosis differs from necrosis in that necrosis ________________. (a) requires the reception of an extracellular signal (b) causes DNA to fragment (c) causes cells to swell and burst, whereas apoptotic cells shrink and condense (d) involves a caspase cascade

causes cells to swell and burst, whereas apoptotic cells shrink and condense

Cadherins ______________________. (a) are used to transfer proteins from one cell to another (b) mediate cell

cell attachments through homophilic interactions (c) are abundant in the plant cell wall (d) bind to collagen fibrils - mediate cell-cell attachments through homophilic interactions

The principal microtubule organizing center in animal cells is the ____________.

centrosome

acid-base reaction

chemical reaction that involves a transfer of protons

At the end of DNA replication, the sister chromatids are held together by the (a) kinetochores (b) securins (c) cohesins (d) histones

cohesins

Which of the following molecules are not found in plants? a. cellulose b. lignin c. collagen d. pectin

collagen

fibrous protein that, in its many forms, is a major component of the extracellular matrix and connective tissue

collagen

Golgi apparatus

collection, packaging and distribution

Mouse embryonic stem (ES) cells ______________________. (a) can only be produced through therapeutic cloning (b) can give rise to all tissues and cell types in the body except germ cells (c) can be implanted in foster mothers to produce cloned cows and other animals (d) come from the inner cell mass of early embryos

come from the inner cell mass of early embryos

1830's

compound microscope makes visualization possible to 1 um

Which of the following occurs in prokaryotes, but not eukaryotes? translation in the absence of a ribosome post transcriptional splicing gene regulation concurrent transcription and translation

concurrent transcription and translation

endomembrane system

creates intracellular compartments with different functions (endoplasmic reticulum, Golgi apparatus, lysosomes)

Which of the following statements about cancer is false? a. Viruses cause some cancers b. Tobacco use is responsible for more than 20% of all cancer deaths c. A mutation in even a single cancer

critical gene is sufficient to convert a normal cell into a cancer cell. d. Chemical carcinogens cause cancer by changing the nucleotide sequence of DNA - A mutation in even a single cancer critical gene is sufficient to convert a normal cell into a cancer cell.

Which of the following is not good direct evidence that the cell

cycle control system is conserved through billions of years of divergent evolution? a. A yeast cell lacking Cdk function can use the human Cdk to substitute for its missing Cdk during the cell cycle. b. The amino acid sequences of cyclins in plants are similar to the amino acid sequences of cylins in humans. c. The Cdk proteins in humans share conserved phosphorylation sites with the Cdk proteins in yeast. d. Yeast cells have only one Cdk, whereas humans have many Cdks. - Yeast cells have only one Cdk, whereas humans have many Cdks.

Levels of Cdk activity change during the cell cycle, in part, because ________________. a. the Cdks phosphorylate each other b. the Cdks activate the cyclins c. Cdk degradation precedes entry into the next phase of the cell cycle d. cyclin levels change during the cycle

cyclin levels change during the cycle

Translation occurs in the _____. cytoplasm lysosome nucleus mitochondrion nucleoplasm

cytoplasm

Cadherins are responsible for Ca++

dependent interactions between connexin proteins. - FALSE

type of anchoring, usually formed between two epithelial cells, characterized by dense plaques or protein into which intermediate filaments in the two adjoining cells insert.

desmosomes

A cell with nuclear lamins that cannot be phosphorylated in M phase will be unable to ________________. (a) reassemble its nuclear envelope at telophase (b) disassemble its nuclear lamina at prometaphase (c) begin to assemble a mitotic spindle (d) condense its chromosomes at prophase

disassemble its nuclear lamina at prometaphase

hydrogen bonding

electrical attraction between electronegative atom and partial positive of hydrogen

polar covalent bond

electrons not shared equally

non-polar covalent bond

electrons shared equally

Cells in the G0 state ________________. (a) do not divide (b) cannot re

enter the cell cycle (c) have entered this arrest state from either G1 or G2 (d) have duplicated their DNA - do not divide

cytoplasm

everything between plasma membrane and nuclear membrane; includes membrane-bound organelles

The RNA segments joined to one another by spliceosomes are _____. caps exons snRNPs tails introns

exons

complex network of polysaccharides (such as GAGs or cellulose) and proteins (such as collagen) secreted by cells that serves as a structural element in tissues and also influences tissue development and physiology.

extracellular matrix

The concentration of mitotic cyclin (M cyclin) ________________. (a) rises markedly during M phase (b) is activated by phosphorylation (c) falls toward the end of M phase as a result of ubiquitylation and degradation (d) is highest in G1 phase

falls toward the end of M phase as a result of ubiquitylation and degradation

A yeast cell that enters mitosis prematurely before reaching normal size in G2 will appear as elongated cells.

false

The APC/C polyubiquinates the protein securin in order to stitch epithelial cells together.

false in order to inhibit activity of separase

Aggrecans are the core protein that are responsible for folding the collagen trimmers in the endoplasmic reticulum.

false responsible for withstanding compression in cartilage

Plant cells communicate with other plant cells via gap junctions composed of connexin proteins.

false via plasmodesmata

Integrins are unable to relay signals between the cell and their external environment.

false ABLE

gap junctions connect the cytoskeleton of one cell to that of a neighboring cell or to the extracellular matrix

false, adherens junctions

Cellulose is synthesized inside the cell then exported by exocytosis

false, cellulose is assembled outside the cell

the extracellular matrix is a relatively inert scaffolding that stabilizes the structure of tissues.

false, the extracellular matrix is dynamic

because of their rigid structure, proteoglycans can withstand a large amount of compressive force

false, they are negatively charged and absorb a lot of water

Like the extracellular matrix of animal cells, plant cell walls are composed almost entirely of protein

false, unlike the extracellular matrix of animal cells, plant cell walls are composed almost entirely of cellulose

Leeuwenhoek

father of microbiology; first to observe through nearly 300x magnification through work in glass

building blocks of fats, lipids, membranes

fatty acids

common cell type in connective tissue that secretes an extracellular matrix rich in collagen and other EM molecules

fibroblast

extracellular matrix protein that binds to integrins to promote adhesion of cells to the matrix and to provide guidance to migrating cells during embryogenesis

fibronectin

Robert Hooke

first microscope

Which of the following is not one of the steps in initiation of translation? binding of tRNA carrying formyl methionine to the start codon and small ribosomal subunit recognition and binding of mRNA by the small ribosomal subunit formation of a polypeptide bond binding of the large ribosomal subunit to the small ribosomal subunit

formation of a polypeptide bond

Which of the following precede the re

formation of the nuclear envelope during M phase in animal cells? (a) assembly of the contractile ring (b) decondensation of chromosomes (c) reassembly of the nuclear lamina (d) transcription of nuclear genes - assembly of the contractile ring

Schwann

formulated cell theory

hydrogen bond

further (distance) bond than ionic or covalent

anion

gain electron; negatively charged

water-filled pore in the plasma membrane of animal cells formed by a ring of 6 protein subunits, which link to an identical assembly in an adjoining cell to form a continuous channel between the two cells

gap junction

mitochondria

generate energy to power the cell

molecule

group of atoms held together by energy in stable association

Which of the following does not occur during M phase in animal cells? (a) growth of the cell (b) condensation of chromosomes (c) breakdown of nuclear envelope (d) attachment of chromosomes to microtubules

growth of the cell

like-like protein interactions in which a molecule on one cell binds to an identical, or closely related, molecule on an adjacent cell.

hemophilic binding

high pK

high affinity for protons; weak acid

The block on re

initiation of DNA replication ensures that the daughter cells are aneuploidy (abnormal number of chromosomes). - false

principal receptor on animal cells for binding most extracellular matrix proteins, including collagens, fibronectin, and laminins.

integrins

At desmosomes, cadherin molecules are connected to ________________. (a) actin filaments (b) intermediate filaments (c) microtubules (d) gap junctions

intermediate filaments

pH = pKa

ionized = non-ionized

pH > pKa

ionized form dominates

Gap junctions are dynamic structures that, like conventional ion channels, are gated: they can close by a reversible conformational change in response to changes in the cell. The permeability of gap junctions decreases within seconds, for example, when the intracellular Ca2+ concentration is raised. Speculate why this form of regulation might be important for the health of a tissue.

ions present in high concentration rush into the cell and metabolites leak out. influx Ca2+ into a sick cell causes its gap junctions to dose immediately effectively isolating the cell and preventing damage from spreading in this way.

A basal lamina ______________________. (a) is a thin layer of connective tissue cells and matrix underlying an epithelium (b) is a thin layer of extracellular matrix underlying an epithelium (c) is attached to the apical surface of an epithelium (d) separates epithelial cells from each other

is a thin layer of extracellular matrix underlying an epithelium

A malignant tumor is more dangerous than a benign tumor because ______________________. (a) its cells are proliferating faster (b) it causes neighboring cells to mutate (c) its cells attack and phagocytose neighboring normal tissue cells (d) its cells invade other tissues

its cells invade other tissues

A primary transcript in the nucleus of a eukaryotic cell is _____ the functional mRNA, while a primary transcript in a prokaryotic cell is _____ the functional mRNA. larger than; smaller than the same size as; the same size as the same size as; larger than larger than; the same size as

larger than; the same size as

cation

lose electron; positively charged

low pK

low affinity for protons; strong acid

Which nucleic acid is translated to make a protein? rRNA mRNA DNA tRNA

mRNA

carbon, hydrogen, oxygen, nitrogen

make up 99% of all matter found in living organisms

condensation reaction

making the chain between monomers (water expelled)

Regulation of integrin

mediated adhesion can regulate cell movement. - true

During RNA processing a(n) _____ is added to the 5' end of the RNA. 3' untranslated region a long string of adenine nucleotides 5' untranslated region coding segment modified guanine nucleotide

modified guanine nucleotide

protists

mostly single cells that include algae, water molds, slime molds and protozoa

plants

multicellular, cell walls

animals

multicellular, no cell walls, heterotrophs

stem cells which are more limited in the types of cells that can develop from them (most adult stem cells)

multipotent stem cells

symbiosis

mutual advantage

pH < pKa

non-ionized form dominates

Robert Brown

noticed every plant contained a round structure (nucleus)

building blocks of nucleic acids

nucleotides

mass number

number of protons and neutrons; top left number

atomic number

number of protons; bottom left number

Which of the following statements about tumor suppressor genes is false? a. Gene amplification of a tumor supressor gene is less dangerous than gene amplification of a proto

oncogene b. Cells with one functional copy of a tumor suppressor gene will usually proliferate faster than normal cells. c. Inactivation of tumor supressor genes leads to enhanced cell survival & proliferation d. Individuals w only 1 functional copy of a tumor supressor gene are more prone to cancer than individuals w 2 functional copies of a tumor suppressor gene - Cells with one functional copy of a tumor suppressor gene will usually proliferate faster than normal cells.

Which of the following genetic changes cannot convert a proto

oncogene into an oncogene? (a) A mutation that introduces a stop codon immediately after the codon for the initiator methionine. (b) A mutation within the coding sequence that makes the protein hyperactive. (c) An amplification of the number of copies of the proto-oncogene, causing overproduction of the normal protein. (d) A mutation in the promoter of the proto-oncogene, causing the normal protein to be transcribed and translated at an abnormally high level. - A mutation that introduces a stop codon immediately after the codon for the initiator methionine.

What is recognized by an aminoacyl tRNA synthetase? one amino acid and the set of tRNAs that is coupled to that amino acid the nucleotides needed to synthesize a tRNA the set of redundant codons that specifies one amino acid one specific codon

one amino acid and the set of tRNAs that is coupled to that amino acid

cytosol

only fluid component

Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand? Complementary Identical Covalently bound Permanently base

paired - Complementary

Plasmodesmata ______________________. (a) permit small molecules to pass from one cell to another (b) are found only in animal cells (c) are closed by the neurotransmitter dopamine (d) provide tensile strength

permit small molecules to pass from one cell to another

Condensins ________________. (a) are degraded when cells enter M

phase (b) assemble into complexes on the DNA when phosphorylated by M-Cdk (c) are involved in holding sister chromatids together (d) bind to DNA before DNA replication begins - assemble into complexes on the DNA when phosphorylated by M-Cdk

MPF activity was discovered when cytoplasm from a Xenopus M

phase cell was injected into Xenopus oocytes, inducing the oocytes to form a mitotic spindle. In a control experiment, Xenopus interphase cytoplasm was injected into oocytes and shown not to induce the formation of a mitotic spindle. Which of the following statements is not a legitimate conclusion from the control experiment? - Components of an interphase nucleus are insufficient to cause mitotic spindle formation.

communicating cell to cell junction in plants in which a channel of cytoplasm lined by plasma membrane connect tow adjacent cells through a small pore in their cell walls.

plasmodesmata

stem cells that can become a significant variety of different cell types but are no longer totipotent (generally only embryonic stem cells)

pluripotent stem cells

describes a structural property of epithelial sheets, and their individual cells, which have one surface attached to the basal lamina below and the opposite surface exposed to the medium above.

polarized

protein

polypeptide folded and coiled into a specific conformation

Thin and extensible cell covering on new plant cells that can accommodate their growth

primary cell walls

the most diverse cell group

prokaryotes

Which of the following is part of a DNA molecule? promoters sigma the holoenzyme initiation factors

promoters

Which of the following statements about the anaphase

promoting complex (APC) is false? a. It promotes degradation of proteins that regulate M phase b. It inhibits M-Cdk activity c. It is continuously active throughout the cell cycle d.M-Cdk stimulates its activity - It is continuously active throughout the cell cycle.

5' caps and 3' poly(A) tails of eukaryotic mRNAs _____. protect mRNA from degradation and enhance transcription protect mRNA from degradation and enhance translation mark the beginning and end of introns, respectively act as sites for the start and stop of translation, respectively

protect mRNA from degradation and enhance translation

electronegativity

pull on electrons

Fibroblasts organize the collagen of the extracellular matrix by ______________. (a) cutting and rejoining the fibrils (b) processing procollagen into collagen (c) twisting fibrils together to make ropelike fibers (d) pulling the collagen into sheets or cables after it has been secreted

pulling the collagen into sheets or cables after it has been secreted

strong acid

readily gives up protons (hydrochloric acid)

cytoskeleton

regulates cell shape, movements of material within the cell, movement of cell itself

Post translational modifications include all of the following except _____. addition of carbohydrates to form a glycoprotein formation of covalent bonds between cysteine residues of the amino acid side chains formation of hydrogen bonds among carbonyl and amino groups of the polypeptide backbone removal of introns

removal of introns

An adult hemopoietic stem cell found in the bone marrow ______________________. (a) will occasionally produce epidermal cells when necessary (b) can produce only red blood cells (c) can undergo self

renewing divisions for the lifetime of a healthy animal (d) will express all the same transcription factors as those found in an unfertilized egg - can undergo self-renewing divisions for the lifetime of a healthy animal

central dogma

replication (DNA synthesis), transcription (RNA synthesis) and then translation (translation); the movement from DNA, to RNA, to a protein

Cytokinesis in animal cells ________________. (a) requires ATP (b) leaves a small circular 'scar' of actin filaments on the inner surface of the plasma membrane (c) is often followed by phosphorylation of integrins in the plasma membrane (d) is assisted by motor proteins that pull on microtubules attached to the cell cortex

requires ATP

rigid cell covering laid down in layers inside the initial covering once the cell growth has stopped.

secondary cell wall

protein domain

segment of polypeptide that forms a compact, stable, independently folding structure

Codon

sequence of base 3 base pairs that code for a specific amino acid

covalent bonds

sharing electrons; forming chemical bonds

fungi

single cells (yeasts) and multicellular (mushrooms); cell walls, heterotrophs; dependent on external source of organic compounds

Spliceosomes are composed of _____. snRNPs and other proteins polymerases and ligases introns and exons the RNA transcript and protein snRNPs and snurps

snRNPs and other proteins

During splicing, _____ recognize and remove _____. snRNPs that make up the spliceosome; introns RNAs within the ribosome; exons RNAs within the ribosome; introns snRNPs that make up the spliceosome; exons

snRNPs that make up the spliceosome; introns

Your mom is coming to dinner. All you have for a salad is wilted lettuce. You use your knowledge from cell biology to fix the problem. what do you do?

soak the lettuce in tap water because the lettuce will reabsorb water by osmosis.

Tight junctions ______________________. (a) allow small water

soluble molecules to pass from cell to cell (b) interact with the intermediate filaments inside the cell (c) are formed from claudins and occludins (d) are found in cells in connective tissues - are formed from claudins and occludins

fact

something that has really occurred; something that is true

nucleus

stores genetic information

base

substance that accepts protons (decreases [H+] in solution)

acid

substance that gives up (donates) protons (increases [H+] in solution)

glyocalyx

sugar covering of membrane, carb rich

building blocks of carbohydrates (polysaccharides)

sugars

mRNA

synthesized in the nucleus

5' cap

the addition of a 7-methylguanosine cap on the 5' end is known as the __ ______. This is a recognition signal for translation machinery.

A major distinction between the connective tissues in an animal and other main tissue types such as epithelium, nervous tissue, or muscle is _______________. (a) the ability of connective tissue cells such as fibroblasts to change shape (b) the amount of extracellular matrix in connective tissues (c) the ability of connective tissues to withstand mechanical stresses (d) the numerous connections that connective tissue cells make with each other

the amount of extracellular matrix in connective tissues

During transcription in eukaryotes, a type of RNA polymerase called RNA polymerase II moves along the template strand of the DNA in the 3'→5' direction. However, for any given gene, either strand of the double stranded DNA may function as the template strand. For any given gene, what ultimately determines which DNA strand serves as the template strand? the base sequence of the gene's promoter the location along the chromosome where the double stranded DNA unwinds the location of specific proteins (transcription factors) that bind to the DNA which of the two strands of DNA carries the RNA primer

the base sequence of the gene's promoter

lysosomes

the cell's waste disposal system and can digest some compounds (mitochondria replaced every 10 days); materials brought into cell by phagocytosis

Gelatin is primarily composed of collagen, which is responsible for the remarkable tensile strength of connective tissue. It is the basic ingredient of jello; yet, as you probably experienced many times yourself while consuming the strawberry-flavored variety, jello has virtually no tensile strength. Why?

the collagen is denatured when boiled. When cooling, disordered fibers form a tangled mess that turn into gel.

Why do you suppose epithelial cells lining the gut are renewed frequently, whereas most neurons last for the lifetime of the organism?

the gut is exposed to acid and rapid turnover protects the organism from harmful consequences, as wounded and sick cells are discarded. neurons live in protected environments and it depends on complex system of connections with other neurons.

A friend declares that chromosomes are held at the metaphase plate by microtubules that push on each chromosome from opposite sides. Which of the following observations does not support your belief that the microtubules are pulling on the chromosomes?

the jiggling movement of chromosomes at the metaphase plate

Which molecule or reaction supplies the energy for polymerization of nucleotides in the process of transcription? ATP only the interaction between RNA polymerase and the promoter the phosphate bonds in the nucleotide triphosphates that serve as substrates the energy released when hydrogen bonds are broken as the DNA molecule is unwound

the phosphate bonds in the nucleotide triphosphates that serve as substrates

Discuss the following statement: "if plant cells contained intermediate filaments to provide the cells with tensile strength, their cell walls would be dispensable."

the plant would have a problem with osmotic pressure because there is no cell wall for turgor pressure. Cell wall is their major defense against pathogens. Intermediate filament network can't provide osmotic pressure for cells

a puzzling observation is that the change of a glycine residue into another amino acid is most detrimental if it occurs toward the amino terminus of the rod-forming domain. Suggest an explanation.

this statement is true because the mutation is at the beginning of chain where it begins to fold.

an occluding junction which seals adjacent epithelial cells together, preventing the passage of most dissolved molecule from one side of the epithelial sheet to the other.

tight junction

Which type of junction contributes the most to the polarization of epithelial cells? (a) adherens junctions (b) desmosomes (c) tight junctions (d) gap junctions

tight junctions

Both multicellular plants and animals have _____________________. (a) cells capable of locomotion (b) cells with cell walls (c) a cytoskeleton composed of actin filaments, microtubules, and intermediate filaments (d) tissues composed of multiple different cell types

tissues composed of multiple different cell types

stem cells that can become any cell in the body (general only very early embryonic stem cells)

totipotent stem cells

What is the process called that converts the genetic information stored in DNA to an RNA copy? Translation Transcription Translocation Replication

transcription

ionic bonds

transferring electrons from one atom to another

Cellulose microfibrils give the plant cell wall its tensile strength.

true

Connective tissue such a tendon and cartilage differs from other solid tissues in that most of its volume is made up of extracellular matrix rather than cells.

true

Initiation of DNA replication occurs at each origin, but only once, until a cell proceeds through anaphase.

true

Integrins couple the matrix outside a cell to the cytoskeleton inside It.

true

Large proteoglycan aggregates may contain a hyaluronin molecule bound to the core protein of multiple proteoglycan molecules.

true

Mitotic CDK kinases are activated by an increase in mitotic cyclins.

true

Passage through the cell cycle is controlled by heterodimeric protein kinases.

true

Procollagen chains are synthesized on the endoplasmic reticulum.

true

Proteoglycan core proteins are synthesized on the endoplasmic reticulum.

true

Small molecules and ions can pass through gap junctions.

true

The cdc25 phosphatase removes a phosphate from the CDK kinase yielding highly active MPF.

true

The staggering of the collagen trimmers gives the fibrils a striated appearance in the electron microscope.

true

a wilted plant leaf can be likened to a deflated bicycle tire.

true

skin cells are continually shed and are renewed every few weeks; for a permanent tattoo, it is therefore necessary to deposit pigment below the epidermis

true

the basal lamina is specialized layer of extracellular matrix to which sheets of epithelial cells are attached.

true

the cells in a plant can be viewed as forming a syncytium, in which many cell nuclei share a common cytoplasm.

true

tight junction perform two distinct functions: they seal the space between cells to restrict paracellular flow and they fence off membrane domains to prevent the mixing of apical and basolateral proteins

true

virtually all epithelia are anchored to other tissues on their basal side and free of such attachment on the apical side

true

although stem cells are not differentiated, they are specialized and therefore give rise only to specific cell types

true, embryonic cells can give rise.

the large internal hydrostatic pressure that develops in plants cells due to the osmotic imbalance between the cell interior and the fluid in the plant cell wall.

turgor pressure

Activation of APC/C leads to the degradation of B

type cyclins which arrests the cell in the G0 stage. - false degradation of securin

concentration of H+ in blood

typically very low

Cells that are terminally differentiated ______________________. (a) will undergo apoptosis within a few days (b) usually can no longer undergo cell division (c) are unable to move (d) no longer produce RNAs

usually can no longer undergo cell division

weak acid

very few molecules dissociated (acetic acid, water)

through the exchange of small metabolites and ions, gap junctions provide metabolic and electrical coupling between cells. why, then, do you suppose the neurons communicate primarily through synapses rather than through gap junctions?

with synapses there is more room for regulation and integration. they also allow signals to be modulated and to be integrated with other signals received by the cell. Gap junctions are like simple joints between electrical components and synapses are like complex relay devices.

Would you expect collagen mutations to be detrimental if only one of the two copies of a collagen gene is defective?

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