Semester 1 Final

Question 1

Which of the following correctly completes the following equation:

Nitrogenous base + sugar + phosphate group = (5 points)

Answer 1

Nucleotide

Question 2

Christiaan Eijkman shared the Nobel Prize in 1929 for the discovery of vitamins. Eijkman went to Java to isolate the pathogen causing beriberi, an illness that appeared to be contagious as it was common in prisons and among ship crews. Eijkman noticed that chickens fed a diet of white rice also suffered from a similar disorder. When the chickens were fed a diet of red rice, the chickens quickly recovered. What can Eijkman safely infer at this point from his observations? (5 points)

Answer 2

Diet may be the cause of beriberi, but more research is needed.

Question 3

If a chemical reaction catalyzed by an enzyme is being carried out and there is a sudden, drastic decrease in temperature, what is most likely to happen next? (5 points)

Answer 3

Enzyme activity will decrease, and the reaction will proceed very slowly, or possibly not at all.

Question 4

Which of the following would most likely be key to gathering evidence that the “RNA World” hypothesis is valid? (5 points)

Answer 4

Simulation of early Earth conditions and long-term study of the resulting molecules

Question 5

Isabella works for an environmental safety group. Her group wants to answer the question “To what lengths must we go to protect plants and animals?” Why is her group’s research question flawed? (5 points)

Answer 5

They are trying to answer an ethical question, not a scientific one.

Question 6

The study of biology is important because it focuses on (5 points)

Answer 6

the interactions of all living things

Question 7

In which of the following ways is the function of the surface of a microsphere similar to the function of an actual cell membrane? (5 points)

Answer 7

Both make it possible for the conditions in the interior to be different from the conditions outside.

Question 8

A group of research scientists believe that their laboratory has gathered scientific evidence for a new cancer treatment drug. What is the primary purpose for reporting their findings in a peer-reviewed scientific journal? (5 points)

Answer 8

To ensure the reliability of the evidence by allowing other scientists to check their findings

Question 9

A scientist who is researching marshes observes that marsh grass, Spartina bakeri, grows to different heights at different locations in the marsh. If the scientist wants to find the reason for this difference, what is the correct first step? (5 points)

Answer 9

Form a research question based on knowledge of the marsh.

Question 10

While looking at a cell under a microscope, a scientist is able to see a biological molecule. This molecule is a nucleic acid with a ladder structure and contains the nitrogenous bases adenine, thymine, cytosine, and guanine. Based on this information, what conclusion can the scientist draw regarding this nucleic acid? (5 points)

Answer 10

The nucleic acid is DNA and would be found in the cell’s nucleus.

Question 11

Which of the following best describes an example of how an enzyme inhibitor can work in a reaction catalyzed by an enzyme? (5 points)

Answer 11

The enzyme inhibitor fits into the enzyme’s active site, which prevents the enzyme from catalyzing the reaction.

Question 12

How are simple carbohydrates able to form larger macromolecules? (5 points)

Answer 12

?

Question 13

Describe what it means for a field of study to be considered a science. Include at least three characteristics or processes necessary for a field of study to be considered a science.

Answer 13

The brief denotation of science that I am able to remember, is that it is the field of study that attempts to explain and prove the natural world. Science must be supported with facts, and it should be replicable by other scientific investigations. In order for science to be defined, it must be followed by three characteristics such as those of observable traits, testable facts, and reliable sources. Within the field of science, there are different definitions such as laws or theories somewhat like postulates and theorems in Geometry, but regardless they should still hold similarities between these traits in order to be considered science at all.

Question 14

Describe the Scientific Method including at least 3 of the steps most likely to be included in a scientific investigation.

Answer 14

The Scientific Method is a set format to how experiments are to be made and followed. Three steps include…

1. Questioning- To create an experiment and follow it with the steps of the Scientific Method we must have a question we are trying to ask. For my example, I will use the question ‘ does moss grow better in sunlight or darkness?’. This question must be something I can test and prove, not an ethical one that is purely based on opinion.
2. Hypothesis- My hypothesis is what I believe the outcome will be before I begin the experiment. For my example question, my hypothesis could be, ‘ I predict that moss will grow better in dark, damp spaces.’ My hypothesis is a prediction, and it can be based on previous research to become more logical as well.
3. Conclusion- Once I have performed my experiment I must form a conclusion. This conclusion can include whether my hypothesis is correct or incorrect, as well as the final results of the experiment. My conclusion should be based on facts and scientific data from my experiment- not opinions.

Question 15

Describe the basic molecular structure of proteins and describe at least 2 biological functions.

Answer 15

The basic molecular structure of proteins is that they are macromolecules, formed by amino acids. Personally, I know a great deal about certain protein functions as I have a metabolic disorder of my own that is affected by some of these. One biological function of a protein is an enzyme. Enzymes are proteins that allow for certain reactions to be sped up or slowed down. This works by decreasing the energy needed in the reaction. Enzymes can be catalyzed as well.
Additionally, another biological protein is called insulin. Insulin is the protein that allows for us to metabolize sugar; this works through the pancreas. Personally, I have an ATP6 gene mutation that affects my energy levels, and recently I have been going through some testing to see if I am metabolizing insulin through my pancreas correctly, for that could be another cause for my bouts of chronic fatigue. If the pancreas is not working correctly, the insulin is not able to reach the cells and use the sugar we digest towards biological functions. It is quite interesting to be able to relate the Biology that I am learning to my own life!

Question 16

How does the use of a scanning electron microscope differ from that of a transmission electron microscope? (4 points)

Answer 16

A scanning electron microscope can be used to study the details of a specimen’s surface, while a transmission electron microscope can be used to study the internal structures of a cell.

Question 17

Which of the following molecules get recycled during photosynthesis? (4 points)

Answer 17

NADPH and ATP

Question 18

Which of the following organelles houses DNA in eukaryotic cells? (4 points)

Answer 18

Nucleus

Question 19

Which of the following correctly describes contrasting features of a plant cell and an animal cell? (4 points)

Answer 19

Plant cells have a large central vacuole that takes up most of the cell’s space, and animal cells have many smaller vacuoles.

Question 20

If the concentration of hydrogen ions (H+) outside of the thylakoids were equal to the concentration of H+ inside the thylakoids, how would it affect the chloroplasts? (4 points)

Answer 20

The chloroplasts would be unable to generate ATP.

Question 21

If the concentration of hydrogen ions (H+) outside of the thylakoids were equal to the concentration of H+ inside the thylakoids, how would it affect the chloroplasts? (4 points)

Answer 21

The chloroplasts would be unable to generate ATP.

Question 22

Prior to the invention of refrigeration, meat was often preserved by soaking it in brine (a solution of water with a high concentration of salt) to kill any microorganisms that might have tried to use the meat as their own food source. Which of the following BEST explains how a brine solution could be lethal to those microorganisms? (4 points)

Answer 22

Water would move out of the cells of the microorganisms by osmosis and the cytoplasm would become dehydrated, killing the cells.

Question 23

Which property of water explains how water droplets are absorbed by a paper towel? (4 points)

Answer 23

Water’s adhesion to other types of molecules

Question 24

Which type of microscope has the lowest magnification power? (4 points)

Answer 24

Dissecting microscope

Question 25

Which of the following outcomes would be most likely if the membrane of a cell were no longer selectively permeable? (4 points)

Answer 25

The cell would die as it would not be able to regulate which substances could enter and leave.

Question 26

Which of the following is needed for cellular respiration to occur? (4 points)

Answer 26

oxygen

Question 27

Which of the following best describes what causes water molecules to exhibit properties such as cohesive and adhesive behavior? (4 points)

Answer 27

Water molecules are polar, having partially positive and partially negative ends.

Question 28

As liquid water freezes, the molecules arrange themselves in a way that takes up more space than liquid water. What would most likely occur if the arrangement of frozen water molecules required less space than that of liquid water molecules? (4 points)

Answer 28

The density of ice would be greater than the density of liquid water, and ice would not float.

Question 29

Which of the following is true of modern cell theory? (4 points)

Answer 29

As technology improves, so will our understanding of cells.

Question 30

Which of the following organelles is found in both plant and animal cells? (4 points)

Answer 30

Mitochondrium

Question 31

Which of the following best describes one way electron microscopes and light microscopes differ in structure? (4 points)

Answer 31

Electron microscopes use a beam of electrons instead of light to magnify images.

Question 32

While the average human is able to hold his or her breath for approximately one minute, a whale can dive for over 30 minutes without returning to the surface. Which of the following correctly describes this difference? (4 points)

Answer 32

Whales are more efficient at gas exchange than humans which helps them conserve energy.

Question 33

When plants wilt, their soft stems and leaves begin to droop. What is going on inside the plants' cells that causes plants to droop like this? (4 points)

Answer 33

The central vacuoles in the cells lose water and can no longer help support the cells.

Question 34

Rudolf Virchow's and Louis Pasteur's work resulted in significant contributions to cell theory but also (4 points)

Answer 34

contradicted the accepted belief in spontaneous generation

Question 35

Runners only have enough stored ATP in their muscle cells to run for about five seconds. Which answer correctly explains how the runner's body adjusts to the longer distance, for example, a marathon (42.1 km)? (4 points)

Answer 35

The runner's body will convert stored fat molecules into energy.

Question 36

How are the proteins used for active transport different from those used for facilitated diffusion? (4 points)

Answer 36

The proteins involved in active transport must be powered by ATP to work.

Question 37

Cellular respiration is a process involving the breakdown of glucose molecules in order to generate energy for cellular activities. Given the general reaction below, which of the following best describes the products labeled x and y? (4 points) C6H12O6 + O2 → _x___ + __y___ + energy

Answer 37

The products are CO2 (carbon dioxide) and H2O (water), which then become the reactants for photosynthesis.

Question 38

What is the function of cellular respiration? What are the reactants and products that result from cellular respiration?

Answer 38

The function of cellular respiration is the ability to produce ATP energy which powers our cells. It is the capacity to use oxygen to utilize the chemical energy stored in molecules. In a plant cell, those molecules would be produced from photosynthesis. As humans, it is simply from our ingested food. The reactants are glucose and oxygen, whilst the products are CO2 and water. There are three steps of cellular respiration: the first is glycolysis which breaks down carbon glucose into pyruvates. The second step is the Krebs cycle, which directs the pyruvate produced into the mitochondria of the cell. The final step, the electron transport chain, is what produces ATP as well as hydrogen ions, oxygen, and water, which are to be used in the round steps once more. This entire cycle is a closed-loop- what is created is needed to react.

Question 39

Explain the significance of ATP in the cell. Describe the ATP molecule, and how its structure relates to its function.

Answer 39

I do happen to have a small bit of outside experience in knowledge regarding the ATP of a cell since I have an ATP6 gene mutation. ATP is the energy stored within food that is used up when chemical bonds are broken and ADP is formed. The ATP molecule is used by the majority of the cell to power its work and movement. It is produced during cellular respiration. The energy that is stored within the ATP can be broken down to be used for other functions, and if I am not mistaken, from the knowledge I have derived from my own neurologists regarding this function, there are different functions of ATP. Such as the ability to produce aerobic differing from anaerobic activity.

Question 40

Compare the functions of a compound light microscope and a scanning electron microscope and give an example of the type of sample that might be best examined by each type of microscope.

Answer 40

Unlike a dissection microscope, a compound light microscope has multiple lenses that allow for better magnification. Compound light microscopes have their own light source that shoots through the examination dish, to allow for a better view. A scanning electron microscope, as well as a transmission electron microscope, works by sending a beam of electrons towards the vacuum-sealed specimen, where the escaped electrons ( or the ones that bounce off of the specimen) are captured to develop an image. These specimens must be thin and coated lightly in gold or a different type of metal. As well, this computer-developed image is black and white. A SET microscope cannot capture images of live specimens, as no living organisms will survive the microscope or preparations for it. So blood, organelle, cells, and any small living specimen will not be able to be viewed by a SET microscope. Whilst perhaps a wing of an insect- a thin specimen- or a strip of a leaf would be able to be viewed in detail. As for a compound light microscope, living organisms can be viewed. So blood, cells, or follicles of hair are most usefully viewed with this microscope.

Question 41

A body cell has been growing and synthesizing proteins. In the nucleus of this body cell, DNA replication is taking place, and a copy of the cell's genetic material is copied. Which of the following is the best conclusion you can make about the life cycle of this cell? (4 points)

Answer 41

The cell is in the S phase of interphase and will move next to the G2 phase.

Question 42

In fruit flies, the allele for ebony body color is recessive to the allele for brown body color. In a generation of fruit flies with 103 offspring, 51 males and 52 females had ebony bodies. Which of the following is the best conclusion you can make about the parents of this generation? (4 points)

Answer 42

Both parents were homozygous with ebony bodies.

Question 43

In order for an inherited genetic mutation to result in a phenotypic change for a recessive trait, which of the following must occur? (4 points)

Answer 43

The mutation must be inherited by both parents.

Question 44

After a natural disaster, aid agencies typically make providing clean drinking water a priority. Why would water be a priority when most victims have major problems, such as the loss of a home, to deal with? (4 points)

Answer 44

Water sources can get contaminated and infect large groups of people.

Question 45

If a mother carries a recessive allele for a genetic disorder, such as cystic fibrosis, under what circumstances will her children inherit the disorder? (4 points)

Answer 45

The children's father must also carry the recessive allele.

Question 46

The children's father must also carry the recessive allele.

Answer 46

They will have a mixture of white feathers and black feathers.

Question 47

Some organisms undergo asexual reproduction through mitosis, while others reproduce sexually, and their cells undergo meiosis to produce gametes. If there were drastic changes in temperature in an ecosystem, which process do you predict would be most beneficial to a species? (4 points)

Answer 47

Meiosis: it increases genetic variation, which helps ensure the species will survive.

Question 48

A fox's diploid number of chromosomes is 36. How would the number of chromosomes in the fox's body cells compare to the number of chromosomes in its gametes? (4 points)

Answer 48

Its body cells would have 36 chromosomes, and its gametes would have 18 chromosomes.

Question 49

DNA is a double helix with many regions. Which evidence best explains the structure of DNA? (4 points)

Answer 49

The sequence of genes on a DNA molecule contain the instructions that code for proteins.

Question 50

The human genome project has allowed for great progress in identifying genetic markers for disease. Which of the following would be considered an ethical misuse of this information? (4 points)

Answer 50

Using an individual's genetic information to decide who can be covered for health insurance

Question 51

While the DNA in a human skin cell was being replicated, a single base was miscopied. What will be the most likely result of this for the cell in which it happened? (4 points)

Answer 51

If the new sequence codes for the same amino acid as the original cell, it will function normally.

Question 52

In which of the following ways is DNA replication different from DNA transcription? (4 points)

Answer 52

Thymine is used in replication, while uracil is used in transcription.

Question 53

If a tRNA molecule has an anticodon which reads GCU, what was the codon of the mRNA molecule?

Answer 53

CGA

Question 54

While mRNA strands are being created a sequence is sometimes miscopied. What is the best possible outcome for the cell should this take place? (4 points)

Answer 54

The miscopied sequence codes for the same amino acids as the original sequence.

Question 55

During meiosis, the chromatids of homologous chromosomes have just undergone crossing over. Which of the following phases will the cell enter next? (4 points)

Answer 55

Metaphase I

Question 56

A plant breeder is trying to develop a deep purple violet. She knows the violets come in deep purple, light purple, and white. She crosses two violets hoping to produce only the deep color. Which parent plants should she use? (4 points)

Answer 56

Both parent must be PP.

Question 57

A person with the genetic disorder Klinefelter's syndrome has an extra X chromosome. Affected individuals have the genotype XXY. What can you infer is most likely the genetic mutation that results in Klinefelter's syndrome? (4 points)

Answer 57

Non-disjunction during meiosis

Question 58

Describe the steps that are used in setting up a Punnett square to predict the probabilities that offspring will inherit a trait.

Answer 58

A Punnett square predicts the genotype of an offspring regarding the genotype of the parents. To create one I first need to know the type of trait the parents have; homozygous or heterozygous. A homozygous trait has two of the same sized letters, TT, while a heterozygous trait will have two different sized letters Tt. These represent whether the trait is dominant or recessive. I will create a chart to demonstrate this process. Tt and TT are my parents aelles. T t T TT Tt T TT Tt I then calculate each percentage based on a 100% whole. So I can see each allele represents a 50% chance of inheritance! ( 2 TT, 2 Tt out of 4)

Question 59

Why do cells undergo mitosis rather than meiosis to produce cells for growth and repair?

Answer 59

Mitosis is the best-suited process for the 'patching', and growth of cells, while meiosis is the sexual reproduction of such cells. This could likely be because meiosis produces more offspring than mitosis, which allows for a population to grow and flourish much more productively, though I think the best reasoning behind this regards what they produce. While mitosis produces diploid cells that are identical to the parents, which is perfect for the growth and repair of cells, meiosis produces haploid cells which contain half of the chromosomes as the parent's cell. In figurative terms, I would not want the paper cut on my finger to heal with half of the skin and lack identicality.

Question 60

How is DNA fingerprinting done? What is one way scientists use DNA fingerprinting?

Answer 60

A sample of the cells tissue is taken from the fingertip and broken down so that it may release DNA. An enzyme then cuts the DNA into smaller segments so that it may be more easily read than this large mass. Next, the DNA segments we just gained are injected into the wells of a tray. An electric current is applied to the trays, and because DNA is negatively charged, it is attracted to the positive charge of the tray. A DNA probe is added to the tray, which combines with the DNA to create an image that is then photographically developed. Scientists can use DNA fingerprinting to determine the individual apparent at a crime scene, and the overall field of forensic science!

Question 61

Salvatore had grown tired of his fish tank and would like to get rid of the fish and contents of the tank in a nearby freshwater canal. Which argument presents the most devastating consequences of Salvatore's dumping of the tank? (4 points)

Answer 61

He may be introducing an invasive species that will damage the ecosystem.

Question 62

An energy pyramid is composed of oak trees, rabbits, snakes, and eagles. The producers receive 100% of the total energy from the sun and have a total biomass of 30,000 kg. As you move up the energy pyramid, the biomass for each tropic level decreases 10%. What claim can be made about the biomass in this ecosystem? (4 points)

Answer 62

The biomass of the snakes is 300 kg

Question 63

Which of the following best describes the changes that take place in an ecosystem during primary succession? (4 points)

Answer 63

Lichens and mosses grow slowly on newly formed land, followed by grasses, shrubs, and trees. PRIMARY SUCCESSION IS... the progression of growth that develops on newly formed land or surfaces.

Question 64

Describe the path of energy in the “greenhouse effect”. What are three gases that are considered “greenhouse gases”?

Answer 64

1. When the warmth of the sun radiates, a majority of it is absorbed by the earth's surface. A select amount of this is re-emitted by greenhouse gas molecules, while the rest of it is trapped within the heat-absorbing properties of greenhouse gasses. As the greenhouse gases rise, more radiation is trapped within the atmosphere, and the heat of our planet continually increases. 2. Three prominent greenhouse gasses are methane, carbon dioxide, and water vapor.

Question 65

Why do primary consumers depend on producers for energy? Why do producers need decomposers?

Answer 65

1. Primary consumers are unable to digest carbohydrates from sunlight, while producers are. Primary consumers are then able to benefit from the values and energy that they would not normally be able to synthesize with the help of our biospheres producers. 2. Decomposers break down the dead or rotting organisms of our biosphere into digestible organic compounds. Producers are then able to survive off of the compounds the decomposers create. Our entire food chain is quite literally pictured as a chain, where one link cannot fuse with the other if the middle components do not exist.

Question 66

Describe at least two characteristics of an invasive species. What is at least one way that invasive species can disrupt ecosystems?

Answer 66

1. An invasive species is any biotic organism that disrupts an already established ecosystem. Two characteristics of invasive species could include, a surplus in population, and/or a drastic decline in one. When an invasive species is away from its native predators, its population can rise exceptionally, while the ecosystem it is invading can experience a rapid decrease. This not only disrupts food chains but can also lead to extinction. 2. I can think of two disruptions an invasive species can bring. The first disturbance being disease. If an invasive species overruns an established ecosystem, any bacteria or sickness they bring can blight the original animals or plants. The second disruption is the consumption of food. If a predator enters an environment with an already set predator-prey relationship, the two species could be competing for food. With any competition, both organisms are not acquiring the nutrition they need.

Question 67

Sustainability means developing practices which protect the environment while also providing for human needs. Which of the following changes would be most helpful in achieving sustainable agriculture? (4 points)

Answer 67

Rotating crops to replenish the soil with nutrients

Question 68

In a forest ecosystem, a species of bird was introduced. The birds had few predators, and for a period of time its population rose steadily and then roughly leveled off. Which of the following conclusions provides the best explanation for this phenomenon? (4 points)

Answer 68

The ecosystem reached its carrying capacity, and was not able to support continued population growth.

Question 69

Which of the following describes how the winter season affects organisms in the tundra biome? (4 points)

Answer 69

Animals not adapted to cold migrate to warmer regions.

Question 70

Which of the following best describes the role of photosynthesis and cellular respiration in the cycling of carbon through the atmosphere? (4 points)

Answer 70

Cellular respiration in animals puts carbon dioxide in the atmosphere for plants to use during photosynthesis.

Question 71

Which of the following best describes the long-term impact of using a renewable energy source? (4 points)

Answer 71

Biomass releases greenhouse gases when burned.

Question 72

Which of the following is the best example of a way human lifestyles affect environmental systems? (4 points)

Answer 72

Using aerosols that contain chlorofluorocarbons (CFCs) decreases the amount of protective ozone (O3).

Question 73

Wolves travel in packs. Which statement best supports evidence that group behavior increases animal survival? (4 points)

Answer 73

Greater cooperation from individuals will increase the success rate of capturing prey.

Question 74

Which of the following best describes a benefit of one type of nonrenewable energy? (4 points)

Answer 74

Petroleum is relatively inexpensive compared to other forms of energy.

Question 75

Which of the following best describes environmental parameters that should be examined before a city can build a landfill? (4 points)

Answer 75

If leakage from the landfill will be able to contaminate groundwater

Question 76

Which of the following is an example of how a biotic factor can affect the population dynamics in an ecosystem? (4 points)

Answer 76

The population of a predator increases following an increase in the population of its prey.

Question 77

In higher latitudes where lakes freeze over in winter, how do cool fall temperatures help fish make it through the winter? (4 points)

Answer 77

The water in contact with the air sinks and mixes with the less oxygenated water in the deeper levels.

Question 78

Tsunamis are often the result of underwater earthquakes. A tsunami can produce waves of up to 20 meters in height when they reach the shore, causing immense damage. Which of the following is a consequence of these catastrophic events? (4 points)

Answer 78

Loss of biodiversity as habitats are destroyed

Question 79

Scientific research shows that our global climate is changing. The global sea level is rising and ocean temperatures are increasing. Which of the following best predicts an outcome of this global climate change in a coastal ecosystem? (4 points)

Answer 79

The loss of habitat will lead to endangering or extinction of species living there.

Question 80

Which of the following best describes what happens to water molecules after they enter the atmosphere through the process of evaporation? (4 points)

Answer 80

They will cool and form dew, clouds, or fog through condensation.