AP Biology Midterm

A bag of dialysis tubing is filled with a solution containing 0.7 NaCl and 0.2 M sucrose. To two significant figures, what is the solute potential when maintained at 15 degrees C?

-38 bars

A turgid plant cell is placed in pure water and reaches equilibrium. If the solute potential of the cell is -9.0 bar, what is the pressure potential of the cell?

0 bars

The pH of a sample of intestinal fluid is found to be 2.0. What is they hydroxide ion (OH-) concentration of the sample?

1 x 10^-12

A liter of solution with a pH of 2 has how many more H+ than 1L of a solution with a pH 6?

10,000 X

A liter of solution with a pH of 2 has how many more H+ than 1 L of a solution with a pH of 4?

100 X

Several classes of cancer medicines function by halting the replication of DNA and preventing cell division. which organelle is targeted by these medicines?

2. Nucleus

At what point in history of Earth did autotrophs most likely first appear?

2500 million years ago

Cyanide is a poison that interferes with the making of ATP energy molecule during cellular respiration. The activity of which organelle would be most negatively impacted by exposure to cyanide?

3. Mitochondria

A sample of DNA is composed of 15% Cytosine, how much of this DNA sample is composed of Thymine?

35%

A sample of DNA contains 45% Adenine , how much Guanine would the complementary RNA strand contain after transcription?

5%

The codon that codes for arginine could be transcribed from what DNA sequence?

5' - CGA - 3'

Lipids are used for long term energy storage because they contain __ of energy.

9 kcal/g

During aerobic respiration, each molecule of glucose can yield approxiametly 36 molecules of ATP. What might lead to a decrease in the amount of ATP produced in a given system?

A decrease in the amount of oxygen available in the system.

Which phrase best describes a gene?

A segment of a DNA molecule that contains the instructions for producing a trait in an organism

For an enzyme is operating at its maximum rate what needs to occur so that products are produced in greater amounts?

Add more substrate.

Eukaryotic cells are substantially larger than bacteria cells and average over 20 times more volume per surface area than bacteria cells. How can eukaryotic cell membrane provide this higher rate of exchange of materials?

All of the above are true.

The cell theory is one of the unifying themes of biology. Which of the following statements would not be apart of the Cell Theory?

All viruses are composed of cells.

How does plant starch differ from the energy stores of animals?

Animals store energy as glycogen in the liver.

Which two procedures would most likely cause a decrease in the rate of protein digestion?

C. and D. Decreasing the pH to 6 and increasing the temperature to 45 degrees C

Diabetes is a condition characterized by elevated blood sugar levels. One form of diabetes occurs when insulin fails to properly regulate blood sugar levels. Complications from diabetes can include never cell damage and poor blood flow, especially in the feet and legs. IN individuals with diabetes, wounds usually take longer than normal to heal. The failure of a cell to react normally to insulin is most likely the result of a problem with which cellular components?

Cell Membrane Receptors

The unique structure of every protein enables this group of macromolecules to have a variety of functions. Which of the following is not an example of a protein?

Chitin-gives structural support to exoskeletons of arthropods.

The Welwitschia mirabilis is a plant native to Namibia. It has been know to live for 1500 years and can survive up to five years with no rain. A predator of the W. mirabilis is the zebra, an herbivorous mammal. Which of the following is not a difference between a W.mirabilis cell and a zebra cell?

Chloroplast

Carbon monoxide (CO) can fit in the same binding site as oxygen on the hemoglobin molecule. This means that a small amount of CO can drastically decrease hemoglobin' ability to transport O2 throughout the body. Carbon monoxide poisoning occurs when people inhale CO and effectively suffocate. What type of molecule is CO?

Competitive inhibitor

Which species in the chart would be selected as most similar to the newly discovered bird?

D

An alteration of genetic information below A-G-T-A-C-C-G-A-T --> A-G-T-G-A-T

Deletion

If the input of water is labeled with a radioactive isotope of oxygen , 18O, then the O2 gas released is also labeled with 18O. Which is the likely explanation?

During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released.

What procedure would have the least effect on the rate of protein digestion?

E. Decreasing the amount of light

Cells of the pancreas will incorporate radioactively labeled amino acids into proteins. This "tagging" of newly synthesized proteins enables a researcher to track their location. In this case, we are tracking an enzyme secreted by pancreatic cells. What is its most likely pathway?

ER--> Golgi --> vesicles that fuse with plasma membrane.

The ability of plants and algae to photosynthesize may have evovled from cyanobacteria. What is this theory called?

Endosymbiosis

Structure and function is a reoccurring theme in biology. How does the structure of ATP relate to its function of storing energy?

Energy is only released when activated by mitochondrial enzymes.

Which activity would most likely increase the mutation rate in a culture of bacteria being grown in a laboratory experiment?

Exposing the culture to ultraviolet radiation

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?

Facilitated diffusion

If the test tube below were allowed to stand at room temperature for several hours, what process would be occuring in the test tube?

Fermentation and Glycolysis

Which of the following is the correct sequence of events in cellular respiration?

Glycolysis-->Krebs cycle --> Electron Transport Chain

The climate in areas close to bodies of water is usually much more moderate than inland communities. Which property of water is responsible for this?

High Specific Heat

Gastric acid in the stomach produces an environment with a pH of 1-2. Human stomach cells have several ways to survive this environment. Some cells create a mucous layer that physically protects the cells. Other cells produce bicarbonate a molecule that chemically protects the cells by nuetralizing the effects of stomach acid. This ability to keep aspects of cell life in balance and to avoid damage can best be described as what?

Homeostasis

Which is the correct classification of the extra cellular solution when an animal cell is placed in distilled water?

Hypotonic

Researchers believe that RNA is essential to the evolution of life on Earth. Which of the following is not one of the capabilities of RNA that supports this theory?

Immune defense through cell surface carbohydrates.

An animal cell with a solute potential of -2.0 bar is placed into a solution with a solute potential of -1.5 bar. What is the net direction of the water?

Into the cell.

How does the storage of genetic material in eukaryotes differ from prokaryotes?

It is enclosed by a double membrane.

Milk can be transformed into yogurt via the fermentation of the bacteria Lacto bacilius. What is a true statement about this process?

It produces less energy than aerobic respiration but is not dependent on oxygen.

Which of the following is the most important property of water in a pond during prolonged freezing conditions?

It's density decreases as it freezes.

Which of the following is NOT offered as evidence in support of the endosymbiotic theory, the belief that a eukaryotic cell has evolved as a "committee" of prokaryotic cells?

Mitochondria and chloroplasts can break away from eukaryotic cells and live on their own.

One of the largest steps in the evolution of life is the development of eukaryotic cells from prokaryotic cells. Which statement provides evidence for this endosymbiosis theory?

Mitochondria and chloroplasts have double membranes.

Which of the following could be found in autotrophic eukaryotic cells?

Mitochondria, Chloroplasts, Nucleus

An herbicide that interrupts the transfer of electrons and interferes with the synthesis of ATP and NADPH most likely affects which of the following?

Mitochondrial activity.

Endotherms vary greatly in size. Elephants can grow up to 7,000 kg; horses can grow up to 1,000 kg; oppossum can grow up to 7 kg; and mice can group up to 25 g. Which animal would have the highest metabolic rate?

Mouse

Which factor has the greatest influence on the development of new inheritable characteristics?

Mutations of genes in reproductive cells

In addition to ATP, what are the end products of glycolysis?

NADH and pyruvate

The cellular membrane is selectively permeable. Which of the following molecules are able to diffuse directly through the plasma membrane?

Na+

Testosterone and estrogen are lipid-soluble signal molecules that cross the plasma membrane by simple diffusion. If these molecules can enter all cells, why do only specific cells respond to their presence?

Nontarget cells lack the intracellular receptors that, when activated by the signal molecule, can interact wiht genes in the cell's nucleus.

Prevalent in marine environments, cyanobacteria are often referred to as blue-green algae. This name is misleading because cyanobacteria are prokaryotic while algae are eukaryotic. What is another difference between the two?

Nucleus

The endomembrane system utilizes several organelles to transport proteins to the extra cellular fluid. Trace the correct pathway through the endomembrane system during the creation of a protein.

Nucleus, rough ER, smooth ER, Golgi apparatus, plasma membrane

In the following equation for cellular respiration, which molecule would be considered the oxidizing agent?

O2

Membrane-bound organelles have been crucial in the evolution of complex, multicellular organisms. Which of the following best summarizes an advantage of eukaryotic cells having internal membranes?

Organelles isolate specific reactions, increasing metabolic efficiency.

Some photosynthetic bacteria (e.g., purple sulfur bacteria) have only photosystem I, whereas others (e.g., cyanobacteria) have both photosystem I and photosystem II. Which of the following might this observation imply?

Photosynthesis with only photosystem I is more ancestral.

The reactions of photosynthesis are completed during several steps. Which is the correct sequence?

Photosystem II, Photosystem I, Calvin Cycle

Which of the following statements most directly supports the claim that different species of organisms use different metabolic strategies to meet their energy requirements for growth, reproduction, and homeostasis?

Plants generally use starch molecules for storage while animals use glycogen and fats for storage.

Alanine is an amino acid that has a hydrophobic side chain. Which would be a likely product of the dehydration synthesis of several alanine molecules?

Polypeptide chain

In aquatic plants, stomata are located in the upper epidermis. In many land plants, however, stomata are located in the lower epidermis. Why would this adaptation be beneficial for land plants?

Prevents water loss.

Organisms living in a bog enviroment must be able to tolerate nitrogen-poor acidic conditions. These plants produce cheicals that break down the insects into usable compounds. Which compounds present in insects are composed of the amino acids that provide the Venus flytrap and sundew with much of their nitrogen?

Proteins

A codon whose first base is guanine would not code for which amino acid?

Serine

The liver is an organ that detoxifies substances, such as alcohol and drugs. Therefore, liver cells have large amounts of what cellular organelle?

Smooth ER

The Calvin Cycle is a series of reactions during photosynthesis. Which statement is most accurate?

The Calvin cycle uses NADPH and ATP to fix carbon into glucose.

What usually results when a cell fails to maintain homeostasis?

The cell many not function properly or die.

Some chemosynthetic bacteria located in the deep sea use an alternate energy source, as seen in the equation below. Which statement is not correct about this process?

The deep zone environment of the bacteria is aerobic.

Which of the following is a valid explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures?

The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from sticking.

The trip operon a repressible operon in bacteria. The trip operon codes for several genes responsible for the production of tryptophan. If tryptophan is present in the environment, what would occur?

The operon is turned off and transcription stops.

In prokaryotes, the lac operon is an inducible operon that contains genes that code for enzymes that break glucose down into lactose. Which of the following is not true about the lac operon?

The operon is usually off but can be turned off by an inducer.

Lysosomes break open during the process of digestion, releasing enzymes into the cytoplasm. Which statement may explain why the entire cell may not be digested?

The pH of the cytoplasm causes the enzymes to function less effectively.

While the structure of DNA is universal, every strand of DNA codes for different genes. What structural component allows this versatility?

The sequence of bases

A student fills a dialysis membrane bag with a mixture of red dye, yellow dye, and water. He soaks the bag in pure water for 24 hours and then observes that the water outside the bag turns yellow. Which statement best explains the results of this experiment?

The yellow dye molecules are smaller than the red dye molecules.

Mitochondrial diseases are a type of genetic disease in which the defective gene (s) are located in the mitochondrial DNA. Mitochondrial disease can present with varied symptoms depending on where in the body the defective mitochondria are located. The symptoms are most serious when the defective mitochondria are located in the muscles, cerebrum, or nerves. Why would this be true?

These cells use the most energy in the body.

Phospholipids were used in the earliest cellular membranes because of their ability to separate the outer environment from the inner environment. What characteristic enables phospholipids to do this?

They are amphiphillic.

Methanobrevibacter smithii is a member of Archea. This bacteria lives in the human gut and aids in the digestion of polysaccharides. What is a true statement concerning members of this domain?

They contain ribosomes.

If platns are grown for several day sin an atmosphere containing 14CO2 in place of 12CO2, one would expect to find

a large increase in 14C in the starch stored in the roots

An amino sugar called N-acetylmuramic acid is an important building block of the cell wall of some bacteria. Penicillin prevents this amino sugar from being incorporated into the bacterial cell wall. Therefore,

all of the choices are correct

A major function of glycoproteins and glycolipids (carbohydrates and lipid containing molecules) in the cell membrane is to:

allow the cells to communicate

The inability of an organism to produce certain proteins can occur when an organism is lacking an enzyme needed to combine

amino acids

Experiments revealed the following information about a certain molecule: — It can be broken down into amino acids. — It can break down proteins into amino acids. — It is found in high concentrations in the small intestine of humans. This molecule is most likely

an enzyme

Polysaccharides, triacylgycerides, and proteins are similar in that they:

are synthesized from subunits by dehydration reactions.

Which of the following is one of the ways that membranes of winter wheat are able to remain fluid when it is extremely cold?

by increasing the percentage of unsaturated phospholipids in the membrane

All of the following contain amino acids except

cholesterol

Research indicates that acid precipitation can damage living organisms by:

decreasing the amount of available calcium carbonate needed for coral and shell building in oceans.

A normal sequence of DNA bases in a single human skin cell is CATGGC. If this sequence replicates in this cell and becomes GATGGC, this alteration will most likely be passed on to

every cell that develops from it

On hot, dry days, guard cells often close microscopic openings or stomates in plant leaves, conserving water. This is an example of

feedback mechanism for maintaining homeostasis.

Which one of the following metabolic pathways is common in aerobic and anaerobic organisms?

glycolysis

In the thylakoid membranes, what is the main role of the antenna pigment molecules?

harvest protons and transfer light energy to the reaction center chlorophyll.

Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature?

high heat of evaporation

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

hypertonic to the fresh water but hypotonic to the salt solution.

The DNA of a fly and the DNA of a gorilla are made up of subunits that are

in different sequences in each of the two species

In a cellular protein, where would you expect to find a hydrophobic amino acid like valine?

in the interior of the folded protein, away from water.

After a period of 24 hours, the starch molecule will most likely be found:

inside the cell, only

Each time water in a cell freezes slowly, long sharp crystals spear through the membrane structures of the cell. The most reasonable explanation for the bad taste of meat that has "freezer burn" from repeated freezing is the destruction of

lysosomes and resultant auto digestion

The presence of lactic acid in the cells of an animal's muscle tissue is an indication that the

muscle cells have been active during a period of oxygen deficiency.

Oxygen consumption can be used as a measure of metabolic rate because oxygen is

necessary for ATP synthesis by oxidative phosphorylation

Proteins are impacted by all of the following environmental conditions except:

salinity

The tree parts of a nucleotide are:

sugar, phosphate, base

As they flow over rotten logs as a fluid sheet, slime molds appear to lack any partitioning into cell units; however, slime molds do become cellular when they change form to produce spores. The surface of some parasitic flatworms and some insect tissues are a "syncytium" or layer of living material that contains many nuclei and cell organelles but lacks partitioning by cell membranes. These tissues consume food and produce wastes. In light of the cell theory that "all living things are composed of cells," then

the general concept of life is cellular still holds because these organisms still utilize cells sometime in their life, but this shows that cell membrane partitions can be abandoned.

Glycolysis is considered to be less efficient than aerobic respiration because:

the production of ATP is less in glycolysis than in aerobic respiration.