Pennsylvania Keystone Exams Biology

1.Deer browse in Michaux State Forest. One observer says a deer stretched its neck to reach leaves and that the fawns inherited the longer neck from that stretching. Another says the deer tried harder and passed the effort on. Which account matches natural selection?

2.On a bright afternoon, a sycamore along the Schuylkill River in Philadelphia is making sugar in its leaves. Which statement describes photosynthesis?

3.A rower training on the Allegheny River in Pittsburgh builds larger arm muscles over a season and later has a child. Which statement about those larger muscles is correct?

4.A model of DNA in a Lancaster classroom shows two strands held by paired bases. Which pairing rule is correct?

5.Producers in a food web along the Susquehanna near Harrisburg store 10,000 kilojoules. About 10 percent of the energy at one level is available to the next level. About how much energy reaches the primary consumers and the secondary consumers?

6.A student in Erie compares a cottonwood leaf cell with a muscle cell from a gull at Presque Isle. Which comparison is correct?

7.A muscle cell in a hiker on a ridge in the Poconos is releasing energy from food. Which statement describes cellular respiration?

8.A class in Gettysburg compares human body cells, which have 46 chromosomes, with the cells produced by meiosis. Which statement is correct?

9.Chromosomes in a cheek cell from a singer in Philadelphia stay inside a membrane-bound compartment instead of lying free in the cytoplasm. What is that compartment?

10.Muscle cells of a cyclist on the Three Rivers Heritage Trail in Pittsburgh are packed with organelles whose folded inner membranes are the main site of aerobic ATP production. Which organelle is that?

11.A red oak leaf in Fairmount Park builds sugar from carbon dioxide and water while the sun is out. Which organelle carries out that work?

12.Hair cells of a person in Erie are building keratin, which is a protein. Which structure links amino acids to make that protein?

13.What is the main job of the cell membrane in a corn root cell near Lancaster?

14.After watering, a wilted tomato plant in a Lancaster garden firms up as a large sac in each leaf cell fills. What is that sac?

15.A bacterium living in the Susquehanna has ribosomes and a cell membrane, but it has no nucleus around its DNA. Which term fits this cell?

16.A cell from a white oak leaf near Gettysburg has a nucleus, mitochondria, and chloroplasts. Which description fits it?

17.Which set is found in both a deer muscle cell and an oak leaf cell in the Allegheny National Forest?

18.Digestive enzymes made in a pancreas cell in Allentown must leave the cell. They are sorted and packed into membrane sacs by which organelle?

19.On a hot afternoon in Philadelphia, a runner sweats and blood flow near the skin increases, and body temperature stays near its usual range. What is that steady internal balance called?

20.A mallard and a cattail both live at Middle Creek Wildlife Management Area. Which statement is true of both organisms?

21.Oxygen moves from the air in the lungs of a hiker at Hawk Mountain into the blood, from a higher concentration to a lower one. The cells do not spend ATP on that movement. What is it called?

22.Road salt splashes a maple root cell near Erie. The fluid outside is saltier than the fluid inside, and water crosses the membrane toward the saltier side. What is that water movement called?

23.A grape root cell in a vineyard near North East, in Erie County, moves mineral ions in from the soil even though those ions are already more concentrated inside the cell. The cell spends ATP. What is that movement called?

24.Glucose enters a muscle cell of a walker on the Capital Area Greenbelt in Harrisburg through a protein channel, from higher concentration outside to lower concentration inside. The cell does not spend ATP. What is that called?

25.In an example used in Scranton, the liquid outside a red blood cell has a lower concentration of dissolved particles than the inside of the cell. What is that outside liquid called, relative to the cell?

26.A red blood cell in a Pittsburgh example sits in a solution that is saltier than the cell interior. As water crosses the membrane, what happens to the cell?

27.In an Edinboro example, plasma and the interior of a red blood cell have the same solute concentration. Which description is correct?

28.After a rain in the Poconos, water enters a leaf cell and the central vacuole presses the cytoplasm against the cell wall. The cell becomes firm. What is that firm condition called?

29.Ice forms on a pond in Prince Gallitzin State Park and rests on the surface while liquid water stays below. Why does the ice float?

30.A stream in the Laurel Highlands carries dissolved minerals from the rocks it crosses. Which property of water explains that dissolving?

31.In the xylem of a tall white pine in Cook Forest, water molecules attract one another and help hold a continuous column. What is that attraction between water molecules called?

32.Equal masses of pond water from York and dry sand beside that pond sit in the same sun. The water's temperature rises more slowly. Which property of water explains that?

33.Carbon atoms form the backbone of sugars, proteins, fats, and DNA in a brook trout from Loyalsock Creek. What lets carbon build so many kinds of molecules?

34.A runner in Bethlehem eats a starchy meal. Digestion breaks the starch into glucose that muscle cells can use for energy. Which kind of molecule is glucose?

35.The membrane of a cattail root cell along the Susquehanna is mainly a double layer of molecules with water-attracting heads and water-avoiding tails. Which molecules are those?

36.An enzyme in a stomach cell of a person in Reading is a protein. Which smaller units are linked to build that protein?

37.Amylase in the saliva of a student in West Chester speeds the breakdown of starch into sugars, and the amylase is still present afterward. Which statement is correct?

38.A cook in York boils an egg. Proteins in the egg white change shape and firm up, and they no longer work as they did before the heat. What is that shape change called?

39.Leaves of a silver maple on City Island in Harrisburg look green through the summer. Which pigment in the chloroplasts is capturing light for photosynthesis?

40.Algae in a sunny shallow area of Lake Wallenpaupack give off oxygen gas on a bright day. Those oxygen atoms come from which photosynthesis reactant?

41.Cattails along Marsh Creek take in carbon dioxide and build sugar in daylight. Where do the carbon atoms in that sugar come from?

42.A hiker climbing Mount Davis, Pennsylvania's highest point, spends a small molecule as the immediate energy carrier for muscle contraction. Which molecule is that?

43.A river birch leaf beside the Lackawanna River in Scranton has both chloroplasts and mitochondria. Most of the ATP from its aerobic respiration is produced in which organelle?

44.A trout in the Clarion River is using aerobic respiration. Which stage produces the largest share of the ATP?

45.A sprinter's calf muscles at a track in Altoona are working faster than the blood can supply oxygen. The cells make a small amount of ATP from glucose, and lactic acid builds up. What is that pathway called?

46.A corn leaf in a field near Lancaster makes sugar in daylight and also breaks sugar down to release usable energy. Which statement is correct?

47.At midnight, a soybean plant in a field near Lebanon is in full darkness. Which process still continues in its living cells?

48.On a dry afternoon, guard cells narrow the openings on a leaf of a sycamore along the Delaware River in Easton. When those stomata are open, what is the usual tradeoff?

49.A skin cell of a person in Johnstown has 46 chromosomes and divides to repair a small scrape. After mitosis, how many chromosomes does each new cell have?

50.Which process produces egg cells of a brook trout in Kettle Creek, each with half the chromosome number of a trout body cell?

51.A class in Danville uses the usual human counts: an egg has 23 chromosomes and a sperm has 23. How many chromosomes does the zygote have after fertilization?

52.Before a root cell in a willow along the Juniata River divides by mitosis, it copies its DNA. During which part of the cell cycle does that copying happen?

53.After mitosis in a human skin cell in Hershey, the cytoplasm pinches into two parts. What is that division of the cytoplasm called?

54.During meiosis in a dogwood flower bud at Longwood Gardens in Kennett Square, homologous chromosomes exchange pieces. What is that exchange called?

55.A body cell of a white-tailed deer in Ohiopyle State Park has the diploid chromosome number. Why is a sperm cell from that deer called haploid?

56.A human skin cell discussed in a class in Bloomsburg has 46 chromosomes. After the DNA is copied and before the cell divides, how many chromatids are in the cell?

57.DNA in a cell of a hellbender in French Creek is a double-stranded molecule shaped like a twisted ladder. What is that shape called?

58.Before a cell in a tulip poplar at Tyler State Park divides, its DNA is copied. Each new double helix keeps one original strand and gets one new strand. What is that pattern called?

59.A stretch of DNA in a blue jay in Frick Park, Pittsburgh, codes for one protein used in feather color. What is that stretch called?

60.In the nucleus of a cell from a chickadee at Hugh Moore Park in Easton, a gene is copied into messenger RNA. What is that process called?

61.Messenger RNA from a cell in a red oak at Colonel Denning State Park is read at a ribosome, and amino acids are joined in order. What is that step called?

62.RNA is being built from a gene in a hemlock cell at Worlds End State Park. Which base in the RNA pairs with adenine?

63.A class in Kutztown is reading how cells use RNA bases. Which statement about the code is correct?

64.One DNA base in a gene of a sunflower in a Phoenixville garden is replaced, and the protein's amino acids change. What is a change in the DNA sequence called?

65.A mutation arises in a skin cell of a farmer in Lebanon County. A different mutation arises in one of that farmer's cells that will become a gamete. Which mutation can be passed to a child?

66.A muscle cell and a nerve cell from the same person in Wilkes-Barre contain the same genes, but they make different sets of proteins. Which statement explains that?

67.Pea plants in a Lititz garden have a height gene with a tall version and a short version. What are those versions of one gene called?

68.In pea plants in New Holland, tall (T) is dominant to short (t). A plant has the genotype Tt. Which phenotype is expected?

69.Short pea plants in Quarryville show the recessive height phenotype. Tall is T and short is t. What are the genotypes of two short parent plants?

70.A pea plant in Ephrata looks tall, and tall is dominant to short. Which statement uses the terms correctly?

71.Two heterozygous tall pea plants, Tt and Tt, are crossed in Manheim. Tall is dominant to short. What fraction of the offspring are expected to be short?

72.In a Strasburg garden, purple flowers (P) are dominant to white (p). A homozygous purple plant, PP, is crossed with a white plant, pp. What is expected among the offspring?

73.Four-o'clock flowers in a Doylestown yard show incomplete dominance. A homozygous red plant is crossed with a homozygous white plant. What is expected?

74.Cattle near Indiana, Pennsylvania, show codominance for coat color. A red parent and a white parent have a calf with both red hairs and white hairs. Which term fits that pattern?

75.In a family in Shippensburg, one parent has blood-type alleles A and i, and the other has alleles B and i. A and B are both dominant to i, and A and B are both expressed when together. Which blood types can appear in the children?

76.A recessive allele on the X chromosome affects a protein. In a family in Camp Hill, the mother carries the allele and the father does not have it. In the usual human pattern, which children can show the trait?

77.Biologists watching cottontails near Gettysburg use the word fitness. What does fitness mean for natural selection?

78.Brook trout in a cold stream in the Poconos have heritable traits that help them live in cold, oxygen-rich water. What is a heritable trait of that kind called?

79.A box turtle near Carlisle learns a new path across a yard. Which statement about evolution is correct?

80.Bacteria in the soil of a Philadelphia community garden include a few that already have a heritable trait for surviving an antibiotic. After the antibiotic is in the soil, those bacteria make up more of the survivors. What does this show?

81.Two groups of salamanders in the Alleghenies are separated by a long dry ridge and stop mating. Over many generations their heritable traits diverge until they no longer interbreed when they meet again. What is that outcome called?

82.An undisturbed stack of sedimentary rock is exposed in a road cut near Ohiopyle, along the Youghiogheny River. A shell fossil lies in a lower layer, and a different fossil lies in a layer above it. Which fossil is in the older rock?

83.A bat in the Poconos has wing bones, and a person has arm bones. The bones are the same set in the same order, but they do different jobs. What are these structures called?

84.At Valley Forge, a monarch butterfly and a barn swallow both use wings to fly, but the wings are built in different ways. What is this similarity called?

85.A display at a nature center in the Poconos shows tiny hip bones in some snakes. The bones do not support walking, but they match hip bones that other vertebrates use for walking. What are the reduced bones called?

86.A flood on the Susquehanna sharply reduces a small mussel population. By chance, the few survivors do not have the same mix of alleles as the population had before the flood. What is this chance shift called?

87.A grower in Berks County saves seed only from tomato plants that already have sweeter fruit and plants those seeds the next year. After many seasons the harvested fruit is sweeter. What is this called?

88.Fossils in rock near Pittsburgh, matching limb bones, and similar DNA sequences support common ancestry and natural selection. In science, what is a broad explanation backed by many tested lines of evidence called?

89.Algae in the shallows at Presque Isle make sugar from carbon dioxide and water using sunlight. What is their role in the food web?

90.A black bear near Hickory Run State Park eats blueberries and also eats fish. Which feeding label fits the bear?

91.A white-tailed deer in Rothrock State Forest eats leaves and acorns and does not hunt animals. What kind of consumer is the deer?

92.Fungi are breaking down a fallen log in Ricketts Glen State Park, and nutrients return to the soil. What role are the fungi playing?

93.Along the Allegheny River, mayfly nymphs eat algae, and smallmouth bass eat the mayflies. Which path shows the direction of energy flow?

94.Cattails at John Heinz National Wildlife Refuge at Tinicum store 5,000 kilojoules. About 10 percent of the energy at one level is available to the next. About how much is available to primary consumers, and then to secondary consumers?

95.Only a small share of the energy in mayflies along Pennypack Creek in Philadelphia is stored in the fish that eat them. What happens to much of the rest?

96.A sugar maple in Promised Land State Park takes in carbon dioxide while making sugar. A porcupine there breathes out carbon dioxide. Which statement links the two?

97.Bacteria in the soil of a clover field near Lancaster convert nitrogen gas from the air into forms the clover can take up. What is that conversion called?

98.Water leaves the surface of Lake Erie as vapor, later falls as rain on Erie, and also leaves tree leaves in Erie County as vapor. Which names match the lake surface and the leaves?

99.All the brook trout in one pool of Pine Creek form one group. Those trout plus the insects, algae, and herons there form a larger living group. Adding the water, rocks, and temperature makes a system. What are the three levels, in that order?

100.Deer in a woodlot near Chambersburg increase while food is abundant, then level off near the number the woodlot can keep supporting. What is that number called?

101.An April freeze in the Poconos kills many early blossoms whether the plants are crowded or sparse. A disease in a crowded pigeon flock in Philadelphia spreads more easily because the birds are packed together. Which pairing is correct?

102.Two species of sunfish in a Susquehanna backwater both eat the same aquatic insects, and insects are scarce. What is this relationship?

103.Honeybees visit apple blossoms in an Adams County orchard. The bees gather nectar, and pollen moves from flower to flower so the trees can set fruit. What is this relationship?

104.A tick on a white-tailed deer near Raystown Lake takes a blood meal. The tick gains food, and the deer is harmed. What is this relationship?

105.A rockslide along the Lehigh Gorge leaves bare rock with no soil, and lichens show up first. After a fire on a slope near Jim Thorpe, grasses sprout from soil that is still there. Which comparison is correct?

106.Spotted lanternflies have spread through southeastern Pennsylvania, including near Philadelphia. They are not native, and they damage grapevines and other plants. Which term fits them?

107.Fertilizer washes from fields into a slow stretch of the Susquehanna. Algae grow quickly, then die, and decomposers use up dissolved oxygen, which stresses fish. What is this pattern called?

108.Philadelphia, the Poconos, and the Laurel Highlands have cold winters, warm summers, and forests of oaks and maples that drop their leaves in autumn. Which biome is this?