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Biology test 2

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When viewing a specimen through a light microscope, scientists use ________ to distinguish the individual components of cells.
special stains
The ________ is the basic unit of life.
cell
Prokaryotes depend on ________ to obtain some materials and to get rid of wastes.
diffusion
Bacteria that lack fimbriae are less likely to ________.
adhere to cell surfaces
Which of the following organisms is a prokaryote? A. amoeba B. influenza A virus C. charophyte algae D. E. coli
E. coli
Which of the following is surrounded by two phospholipid bilayers? A. the ribosomes B. the vesicles C. the cytoplasm D. the nucleoplasm
the nucleoplasm
Peroxisomes got their name because hydrogen peroxide is: A. used in their detoxification reactions B. produced during their oxidation reactions C. incorporated into their membranes D. a cofactor for the organelles’ enzymes
produced during their oxidation reactions
In plant cells, the function of the lysosomes is carried out by __________.
vacuoles
Which of the following is both in eukaryotic and prokaryotic cells? A. nucleus B. mitochondrion C. vacuole D. ribosomes
ribosomes
Tay-Sachs disease is a genetic disorder that results in the destruction of neurons due to a buildup of sphingolipids in the cells. Which organelle is malfunctioning in Tay-Sachs? A. lysosome B. endoplasmic reticulum C. peroxisome D. mitochondria
lysosome
Which of the following is not a component of the endomembrane system? A. mitochondrion B. Golgi apparatus C. endoplasmic reticulum D. lysosome
mitochondrion
The process by which a cell engulfs a foreign particle is known as: A. endosymbiosis B. phagocytosis C. hydrolysis D. membrane synthesis
phagocytosis
Which of the following is most likely to have the greatest concentration of smooth endoplasmic reticulum? A. a cell that secretes enzymes B. a cell that destroys pathogens C. a cell that makes steroid hormones D. a cell that engages in photosynthesis
a cell that makes steroid hormones
Which of the following sequences correctly lists in order the steps involved in the incorporation of a proteinaceous molecule within a cell? A. protein synthesis of the protein on the ribosome; modification in the Golgi apparatus; packaging in the endoplasmic reticulum; tagging in the vesicle B. synthesis of the protein on the lysosome; tagging in the Golgi; packaging in the vesicle; distribution in the endoplasmic reticulum C. synthesis of the protein on the ribosome; modification in the endoplasmic reticulum; tagging in the Golgi; distribution via the vesicle D. synthesis of the protein on the lysosome; packaging in the vesicle; distribution via the Golgi; tagging in the endoplasmic reticulum
synthesis of the protein on the ribosome; modification in the endoplasmic reticulum; tagging in the Golgi; distribution via the vesicle
Congenital disorders of glycosylation are a growing class of rare diseases. Which organelle would be most commonly involved in the glycoprotein disorder portion of the group? A. RER B. ribosomes C. endosomes D. Golgi apparatus
Golgi apparatus
Which of the following have the ability to disassemble and reform quickly? A. microfilaments and intermediate filaments B. microfilaments and microtubules C. intermediate filaments and microtubules D. only intermediate filaments
microfilaments and microtubules
Which of the following do not play a role in intracellular movement? A. microfilaments and intermediate filaments B. microfilaments and microtubules C. intermediate filaments and microtubules D. only intermediate filaments
only intermediate filaments
In humans, _____ are used to move a cell within its environment while _____ are used to move the environment relative to the cell.
flagella; cilia
Which of the following are found only in plant cells? A. gap junctions B. desmosomes C. plasmodesmata D. tight junctions
plasmodesmata
The key components of desmosomes are cadherins and __________.
intermediate filaments
Diseased animal cells may produce molecules that activate death cascades to kill the cells in a controlled manner. Why would neighboring healthy cells also die? A. The death molecule is passed through desmosomes. B. The death molecule is passed through plasmodesmata. C. The death molecule disrupts the extracellular matrix. D. The death molecule passes through gap junctions.
The death molecule passes through gap junctions.
What are the advantages and disadvantages of each of these types of microscopes?
The advantages of light microscopes are that they are easily obtained, and the light beam does not kill the cells. However, typical light microscopes are somewhat limited in the amount of detail they can reveal. Electron microscopes are ideal because you can view intricate details, but they are bulky and costly, and preparation for the microscopic examination kills the specimen.
Antibiotics are medicines that are used to fight bacterial infections. These medicines kill prokaryotic cells without harming human cells. What part or parts of the bacterial cell do you think antibiotics target? Why?
The cell wall would be targeted by antibiotics as well as the bacteria's ability to replicate. This would inhibit the bacteria's ability to reproduce, and it would compromise its defense mechanisms.
In the context of cell biology, what do we mean by form follows function? What are at least two examples of this concept?
"Form follows function" refers to the idea that the function of a body part dictates the form of that body part. As an example, compare your arm to a bat's wing. While the bones of the two correspond, the parts serve different functions in each organism and their forms have adapted to follow that function.
Which plasma membrane component can be either found on its surface or embedded in the membrane structure? A. protein B. cholesterol C. carbohydrate D. phospholipid
protein
Which characteristic of a phospholipid contributes to the fluidity of the membrane? A. its head B. cholesterol C. a saturated fatty acid tail D. double bonds in the fatty acid tail
double bonds in the fatty acid tail
What is the primary function of carbohydrates attached to the exterior of cell membranes? A. identification of the cell B. flexibility of the membrane C. strengthening the membrane D. channels through membrane
identification of the cell
A scientist compares the plasma membrane composition of an animal from the Mediterranean coast with one from the Mojave Desert. Which hypothesis is most likely to be correct? A. The cells from the Mediterranean coast animal will have more fluid plasma membranes. B. The cells from the Mojave Desert animal will have a higher cholesterol concentration in the plasma membranes. C. The cells’ plasma membranes will be indistinguishable. D. The cells from the Mediterranean coast animal will have a higher glycoprotein content, while the cells from the Mojave Desert animal will have a higher lipoprotein content.
The cells from the Mojave Desert animal will have a higher cholesterol concentration in the plasma membranes.
Water moves via osmosis _________.
from an area with a high concentration of water to one of lower concentration
The principal force driving movement in diffusion is the __________.
concentration gradient
What problem is faced by organisms that live in fresh water? A. Their bodies tend to take in too much water. B. They have no way of controlling their tonicity. C. Only salt water poses problems for animals that live in it. D. Their bodies tend to lose too much water to their environment.
Their bodies tend to take in too much water.
In which situation would passive transport not use a transport protein for entry into a cell? A. water flowing into a hypertonic environment B. glucose being absorbed from the blood C. an ion flowing into a nerve cell to create an electrical potential D. oxygen moving into a cell after oxygen deprivation
Oxygen moving into a cell after oxygen deprivation
Active transport must function continuously because __________.
diffusion is constantly moving solutes in opposite directions
How does the sodium-potassium pump make the interior of the cell negatively charged? A. by expelling anions B. by pulling in anions C. by expelling more cations than are taken in D. by taking in and expelling an equal number of cations
by expelling more cations than are taken in
What is the combination of an electrical gradient and a concentration gradient called? A. potential gradient B. electrical potential C. concentration potential D. electrochemical gradient
electrochemical gradient
What happens to the membrane of a vesicle after exocytosis? A. It leaves the cell. B. It is disassembled by the cell. C. It fuses with and becomes part of the plasma membrane. D. It is used again in another exocytosis event.
It fuses with and becomes part of the plasma membrane.
Which transport mechanism can bring whole cells into a cell? A. pinocytosis B. phagocytosis C. facilitated transport D. primary active transport
phagocytosis
In what important way does receptor mediated endocytosis differ from phagocytosis? A. It transports only small amounts of fluid. B. It does not involve the pinching off of membrane. C. It brings in only a specifically targeted substance. D. It brings substances into the cell, while phagocytosis removes substances.
It brings in only a specifically targeted substance
Many viruses enter host cells through receptor-mediated endocytosis. What is an advantage of this entry strategy? A. The virus directly enters the cytoplasm of the cell. B. The virus is protected from recognition by white blood cells. C. The virus only enters its target host cell type. D. The virus can directly inject its genome into the cell’s nucleus.
The virus only enters its target host cell type.
Which of the following organelles relies on exocytosis to complete its function? A. Golgi apparatus B. vacuole C. mitochondria D. endoplasmic reticulum
Golgi apparatus
Why is it advantageous for the cell membrane to be fluid in nature?
The fluid characteristic of the cell membrane allows greater flexibility to the cell than it would if the membrane were rigid. It also allows the motion of membrane components, required for some types of membrane transport.
Discuss why the following affect the rate of diffusion: molecular size, temperature, solution density, and the distance that must be traveled.
Heavy molecules move more slowly than lighter ones. It takes more energy in the medium to move them along. Increasing or decreasing temperature increases or decreases the energy in the medium, affecting molecular movement. The denser a solution is, the harder it is for molecules to move through it, causing diffusion to slow down due to friction. Living cells require a steady supply of nutrients and a steady rate of waste removal. If the distance these substances need to travel is too great, diffusion cannot move nutrients and waste materials efficiently to sustain life.
Where does the cell get energy for active transport processes?
The cell harvests energy from ATP produced by its own metabolism to power active transport processes, such as the activity of pumps.
Why is it important that there are different types of proteins in plasma membranes for the transport of materials into and out of a cell?
The proteins allow a cell to select what compound will be transported, meeting the needs of the cell and not bringing in anything else.
Look at each of the processes, and decide if it is endergonic or exergonic. In each case, does enthalpy increase or decrease, and does entropy increase or decrease?
A compost pile decomposing is an exergonic process; enthalpy increases (energy is released) and entropy increases (large molecules are broken down into smaller ones). A baby developing from a fertilized egg is an endergonic process; enthalpy decreases (energy is absorbed) and entropy decreases. Sand art being destroyed is an exergonic process; there is no change in enthalpy, but entropy increases. A ball rolling downhill is an exergonic process; enthalpy decreases (energy is released), but there is no change in enthalpy.
Energy is stored long-term in the bonds of _____ and used short-term to perform work from a(n) _____ molecule.
glucose : ATP
DNA replication involves unwinding two strands of parent DNA, copying each strand to synthesize complementary strands, and releasing the parent and daughter DNA. Which of the following accurately describes this process? A. This is an anabolic process. B. This is a catabolic process. C. This is both anabolic and catabolic. D. This is a metabolic process but is neither anabolic nor catabolic.
This is an anabolic process
Consider a pendulum swinging. Which type(s) of energy is/are associated with the pendulum in the following instances: i. the moment at which it completes one cycle, just before it begins to fall back towards the other end, ii. the moment that it is in the middle between the two ends, and iii. just before it reaches the end of one cycle (just before instant i.). A. i. potential and kinetic, ii. potential and kinetic, iii. kinetic B. i. potential, ii. potential and kinetic, iii. potential and kinetic C. i. potential, ii. kinetic, iii. potential and kinetic D. i. potential and kinetic, ii. kinetic iii. kinetic
i. potential, ii. kinetic, iii. potential and kinetic
Which of the following comparisons or contrasts between endergonic and exergonic reactions is false? A. Endergonic reactions have a positive ∆G and exergonic reactions have a negative ∆G. B. Endergonic reactions consume energy and exergonic reactions release energy. C. Both endergonic and exergonic reactions require a small amount of energy to overcome an activation barrier. D. Endergonic reactions take place slowly and exergonic reactions take place quickly.
Endergonic reactions take place slowly and exergonic reactions take place quickly
In each of the three systems, determine the state of entropy (low or high) when comparing the first and second: i. the instant that a perfume bottle is sprayed compared with 30 seconds later, ii. an old 1950s car compared with a brand new car, and iii. a living cell compared with a dead cell. A. i. low, ii. high, iii. low B. i. low, ii. high, iii. high C. i. high, ii. low, iii. high D. i. high, ii. low, iii. low
i. low, ii. high, iii. low
Which of the following molecules is likely to have the most potential energy? A. sucrose B. ATP C. glucose D. ADP
sucrose
An allosteric inhibitor does which of the following?
Binds to an enzyme away from the active site and changes the conformation of the active site, decreasing its affinity for the substrate
Does physical exercise involve anabolic and/ or catabolic processes? Give evidence for your answer.
Physical exercise involves both anabolic and catabolic processes. Body cells break down sugars to provide ATP to do the work necessary for exercise, such as muscle contractions. This is catabolism. Muscle cells also must repair muscle tissue damaged by exercise by building new muscle. This is anabolism.
Imagine an elaborate ant farm with tunnels and passageways through the sand where ants live in a large community. Now imagine that an earthquake shook the ground and demolished the ant farm. In which of these two scenarios, before or after the earthquake, was the ant farm system in a state of higher or lower entropy?
The ant farm had lower entropy before the earthquake because it was a highly ordered system. After the earthquake, the system became much more disordered and had higher entropy
Explain in your own words how enzyme feedback inhibition benefits a cell.
Feedback inhibition allows cells to control the amounts of metabolic products produced. If there is too much of a particular product relative to what the cell's needs, feedback inhibition effectively causes the cell to decrease production of that particular product. In general, this reduces the production of superfluous products and conserves energy, maximizing energy efficiency.
Cyanide inhibits cytochrome c oxidase, a component of the electron transport chain. If cyanide poisoning occurs, would you expect the pH of the intermembrane space to increase or decrease? What effect would cyanide have on ATP synthesis?
After cyanide poisoning, the electron transport chain can no longer pump electrons into the intermembrane space. The pH of the intermembrane space would increase, the pH gradient would decrease, and ATP synthesis would stop.
The energy currency used by cells is ________.
ATP
A reducing chemical reaction ________.
adds an electron to the substrate
During the second half of glycolysis, what occurs? A. ATP is used up. B. Fructose is split in two. C. ATP is made. D. Glucose becomes fructose.
ATP is made
What is removed from pyruvate during its conversion into an acetyl group? A. oxygen B. ATP C. B vitamin D. carbon dioxide
carbon dioxide
What do the electrons added to NAD + do? A. They become part of a fermentation pathway. B. They go to another pathway for ATP production. C. They energize the entry of the acetyl group into the citric acid cycle. D. They are converted to NADP.
They go to another pathway for ATP production.
How many NADH molecules are produced on each turn of the citric acid cycle?
3
Chemiosmosis involves ________.
the movement of hydrogen ions across a mitochondrial membrane
Which of the following fermentation methods can occur in animal skeletal muscles? A. lactic acid fermentation B. alcohol fermentation C. mixed acid fermentation D. propionic fermentation
lactic acid fermentation
The control of which enzyme exerts the most control on glycolysis? A. hexokinase B. phosphofructokinase C. glucose-6-phosphatase D. aldolase
phosphofructokinase
Nearly all organisms on earth carry out some form of glycolysis. How does that fact support or not support the assertion that glycolysis is one of the oldest metabolic pathways?
If glycolysis evolved relatively late, it likely would not be as universal in organisms as it is. It probably evolved in very primitive organisms and persisted, with the addition of other pathways of carbohydrate metabolism that evolved later.
Because they lose their mitochondria during development, red blood cells cannot perform aerobic respiration; however, they do perform glycolysis in the cytoplasm. Why do all cells need an energy source, and what would happen if glycolysis were blocked in a red blood cell?
All cells must consume energy to carry out basic functions, such as pumping ions across membranes. A red blood cell would lose its membrane potential if glycolysis were blocked, and it would eventually die.
What accounts for the different number of ATP molecules that are formed through cellular respiration?
Few tissues except muscle produce the maximum possible amount of ATP from nutrients. The intermediates are used to produce needed amino acids, fatty acids, cholesterol, and sugars for nucleic acids. When NADH is transported from the cytoplasm to the mitochondria, an active transport mechanism is used, which decreases the amount of ATP that can be made. The OpenStax Biology 2e Instructor Answer Guide electron transport chain differs in composition between species, so different organisms will make different amounts of ATP using their electron transport chains.
What is the primary difference between fermentation and anaerobic respiration?
Fermentation uses glycolysis only. Anaerobic respiration uses all three parts of cellular respiration, including the parts in the mitochondria like the citric acid cycle and electron transport; it also uses a different final electron acceptor instead of oxygen gas.
Which of the following components is not used by both plants and cyanobacteria to carry out photosynthesis? A. chloroplasts B. chlorophyll C. carbon dioxide D. water
chloroplasts
What two main products result from photosynthesis? A. oxygen and carbon dioxide B. chlorophyll and oxygen C. sugars/carbohydrates and oxygen D. sugars/carbohydrates and carbon dioxide
sugars/carbohydrates and oxygen
In which compartment of the plant cell do the light-independent reactions of photosynthesis take place?
stroma
Which statement about thylakoids in eukaryotes is not correct? A. Thylakoids are assembled into stacks. B. Thylakoids exist as a maze of folded membranes. C. The space surrounding thylakoids is called stroma. D. Thylakoids contain chlorophyll.
Thylakoids exist as a maze of folded membranes.
Predict the end result if a chloroplast's light-independent enzymes developed a mutation that prevented them from activating in response to light. A. G3P accumulation B. ATP and NADPH accumulation C. Water accumulation D. Carbon dioxide depletion
ATP and NADPH accumulation
How are the NADPH and GA3P molecules made during photosynthesis similar? A. They are both end products of photosynthesis. B. They are both substrates for photosynthesis. C. They are both produced from carbon dioxide. D. They both store energy in chemical bonds.
They both store energy in chemical bonds.
Which of the following structures is not a component of a photosystem? A. ATP synthase B. antenna molecule C. reaction center D. primary electron acceptor
ATP synthase
How many photons does it take to fully reduce one molecule of NADP + to NADPH?
2
Which complex is not involved in the establishment of conditions for ATP synthesis? A. photosystem I B. ATP synthase C. photosystem II D. cytochrome complex
photosystem II
From which component of the light dependent reactions does NADPH form most directly? A. photosystem II B. photosystem I C. cytochrome complex D. ATP synthase
photosystem I
Three of the same species of plant are each grown under a different colored light for the same amount of time. Plant A is grown under blue light, Plant B is grown under green light, and Plant C is grown under orange light. Assuming the plants use only chlorophyll a and chlorophyll b for photosynthesis, what would be the predicted order of the plants from most growth to least growth?
A, C, B
Plants containing only chlorophyll b are exposed to radiation with the following wavelengths: 10nm (x-rays), 450nm (blue light), 670nm (red light), and 800nm (infrared light). Which plants harness the most energy for photosynthesis?
Blue light irradiated plants
Which molecule must enter the Calvin cycle continually for the light-independent reactions to take place?
CO 2
Which order of molecular conversions is correct for the Calvin cycle? A. RuBP + G3P → 3-PGA → sugar B. RuBisCO → CO2 → RuBP → G3P C. RuBP + CO2 → [RuBisCO] 3-PGA → G3P D. CO2 → 3-PGA → RuBP → G3P
RuBP + CO 2 → [RuBisCO] 3-PGA → G3P
Where in eukaryotic cells does the Calvin cycle take place?
chloroplast stroma
Which statement correctly describes carbon fixation? A. the conversion of CO2 into an organic compound B. the use of RuBisCO to form 3-PGA C. the production of carbohydrate molecules from G3P D. the formation of RuBP from G3P molecules E. the use of ATP and NADPH to reduce CO2
the conversion of CO 2 into an organic compound
If four molecules of carbon dioxide enter the Calvin cycle (four "turns" of the cycle), how many G3P molecules are produced and how many are exported?
8 G3P made, 1 G3P exported
What is the overall outcome of the light reactions in photosynthesis?
The outcome of light reactions in photosynthesis is the conversion of solar energy into chemical energy that the chloroplasts can use to do work (mostly anabolic production of carbohydrates from carbon dioxide).
Describe how the grey wolf population would be impacted by a volcanic eruption that spewed a dense ash cloud that blocked sunlight in a section of Yellowstone National Park.
The grey wolves are apex predators in their food web, meaning they consume smaller prey animals and are not the prey of any other animal. Blocking sunlight would prevent the plants at the bottom of the food web from performing photosynthesis. This would kill many of the plants, reducing the food sources available to smaller animals in Yellowstone. A smaller prey animal population means that fewer wolves can survive in the area, and the population of grey wolves will decrease.
Imagine a sealed terrarium containing a plant and a beetle. How does each organism provide resources for the other? Could each organism survive if it was the only living thing in the terrarium? Why or why not?
An energy cycle between a plant and a beetle would be as follows: A. Plant consumes carbon dioxide and releases oxygen as a by-product of photosynthesis B. Beetle consumes oxygen and releases carbon dioxide to create chemical energy during aerobic respiration C. Plant takes up carbon dioxide from the air D. Repeat cycle
What property prevents the ligands of cell-surface receptors from entering the cell? A. The molecules bind to the extracellular domain. B. The molecules are hydrophilic and cannot penetrate the hydrophobic interior of the plasma membrane. C. The molecules are attached to transport proteins that deliver them through the bloodstream to target cells. D. The ligands are able to penetrate the membrane and directly influence gene expression upon receptor binding.
The molecules are hydrophilic and cannot penetrate the hydrophobic interior of the plasma membrane.
The secretion of hormones by the pituitary gland is an example of _______________.
endocrine signaling
Why are ion channels necessary to transport ions into or out of a cell? A. Ions are too large to diffuse through the membrane. B. Ions are charged particles and cannot diffuse through the hydrophobic interior of the membrane. C. Ions do not need ion channels to move through the membrane. D. Ions bind to carrier proteins in the bloodstream, which must be removed before transport into the cell.
Ions are charged particles and cannot diffuse through the hydrophobic interior of the membrane.
Endocrine signals are transmitted more slowly than paracrine signals because ___________.
the ligands are transported through the bloodstream and travel greater distances
A scientist notices that when she adds a small, water-soluble molecule to a dish of cells, the cells turn off transcription of a gene. She hypothesizes that the ligand she added binds to a(n) ______ receptor.
Enzyme-linked
Apoptosis can occur in a cell when the cell is ________________.
damaged, no longer needed, infected by a virus
What is the effect of an inhibitor binding an enzyme?
The enzyme is inactivated.
Quorum sensing is triggered to begin when ___________.
a sufficient number of bacteria are present
What are the differences between internal receptors and cell-surface receptors?
Internal receptors are located inside the cell, and their ligands enter the cell to bind the receptor. The complex formed by the internal receptor and the ligand then enters the nucleus and directly affects protein production by binding to the chromosomal DNA and initiating the making of mRNA that codes for proteins. Cell surface receptors, however, are embedded in the plasma membrane, and their ligands do not enter the cell. Binding of the ligand to the cell- surface receptor initiates a cell signaling cascade and does not directly influence the making of proteins; however, it may involve the activation of intracellular proteins.
Which of the following is the correct order of events in mitosis?
The kinetochore becomes attached to the mitotic spindle. Sister chromatids line up at the metaphase plate. Cohesin proteins break down and the sister chromatids separate. The nucleus reforms and the cell divides.
Human papillomavirus can cause cervical cancer. The virus encodes E6, a protein that binds p53. Based on this fact and what you know about p53, what effect do you think E6 binding has on p53 activity? A. E6 activates p53 B. E6 inactivates p53 C. E6 mutates p53 D. E6 binding marks p53 for degradation
E6 binding marks p53 for degradation.
If a mutation occurs so that a fungus is no longer able to produce a minus mating type, will it still be able to reproduce?
Yes, it will be able to reproduce asexually.
Explain how the random alignment of homologous chromosomes during metaphase I contribute to the variation in gametes produced by meiosis.
Random alignment leads to new combinations of traits. The chromosomes that were originally inherited by the gamete-producing individual came equally from the egg and the sperm. In metaphase I, the duplicated copies of these maternal and paternal homologous chromosomes line up across the center of the cell to form a tetrad. The orientation of each tetrad is random. There is an equal chance that the maternally derived chromosomes will be facing either pole. The same is true of the paternally derived chromosomes. The alignment should occur differently in almost every meiosis. As the homologous chromosomes are pulled apart in anaphase I, any combination of maternal and paternal chromosomes will move toward each pole. The gametes formed from these two groups of chromosomes will have a mixture of traits from the individual's parents. Each gamete is unique.
Compare and contrast a human somatic cell to a human gamete.
Human somatic cells have 46 chromosomes: 22 pairs and 2 sex chromosomes that may or may not form a pair. This is the 2n or diploid condition. Human gametes have 23 chromosomes, one each of 23 unique chromosomes, one of which is a sex chromosome. This is the n or haploid condition.
In your opinion, is the nuclear membrane part of the endomembrane system? Why or why not? Defend your answer.
Since the external surface of the nuclear membrane is continuous with the rough endoplasmic reticulum, which is part of the endomembrane system, then it is correct to say that it is part of the system.
Chemotherapy drugs such as vincristine (derived from Madagascar periwinkle plants) and colchicine (derived from autumn crocus plants) disrupt mitosis by binding to tubulin (the subunit of microtubules) and interfering with microtubule assembly and disassembly. Exactly what mitotic structure is targeted by these drugs and what effect would that have on cell division?
The mitotic spindle is formed of microtubules. Microtubules are polymers of the protein tubulin; therefore, it is the mitotic spindle that is disrupted by these drugs. Without a functional mitotic spindle, the chromosomes will not be sorted or separated during mitosis. The cell will arrest in mitosis and die.
Why do phospholipids tend to spontaneously orient themselves into something resembling a membrane?
The hydrophobic, nonpolar regions must align with each other in order for the structure to have minimal potential energy and, consequently, higher stability. The fatty acid tails of the phospholipids cannot mix with water, but the phosphate "head" of the molecule can. Thus, the head orients to water, and the tail to other lipids.
How does the closing of the stomata limit photosynthesis?
The stomata regulate the exchange of gases and water vapor between a leaf and its surrounding environment. When the stomata are closed, the water molecules cannot escape the leaf, but the leaf also cannot acquire new carbon dioxide molecules from the environment. This limits the light-independent reactions to only continuing until the carbon dioxide stores in the leaf are depleted.
In a comparison of the stages of meiosis to the stages of mitosis, which stages are unique to meiosis and which stages have the same events in both meiosis and mitosis?
All of the stages of meiosis I, except possibly telophase I, are unique because homologous chromosomes are separated, not sister chromatids. In some species, the chromosomes do not decondense and the nuclear envelopes do not form in telophase I. All of the stages of meiosis II have the same events as the stages of mitosis, with the possible exception of prophase II. In some species, the chromosomes are still condensed and there is no nuclear envelope. Other than this, all processes are the same.
What is the relationship between a genome, chromosomes, and genes?
The genome consists of the sum total of an organism's chromosomes. Each chromosome contains hundreds and sometimes thousands of genes, segments of DNA that code for a polypeptide or RNA, and a large amount of DNA with no known function.
What is anabolism?
requires energy to grow and build
What is catabolism?
uses energy to break down