Branches of Science Part I

Cells

100

Which of the following is found in BOTH plant and animal cells?

^{(A) Lysosome}

^{(B) Cell Wall}

^{(C) Nucleus}

^{(D) Chloroplast}

CORRECT ANSWER: “C” NUCLEUS 

^{Both plant and animal cells are eukaryotes, so they both will contain a nucleus.}

200

Why do prokaryotic cells usually reproduce more quickly than eukaryotic cells?

^{(A) Eukaryotic cells are smaller than prokaryotic cells.}

^{(B)Eukaryotic cells are more structurally complex than prokaryotic cells.}

^{(C) Eukaryotic cells have less DNA than prokaryotic cells.}

^{(D) Eukaryotic cells have more cell walls than prokaryotic cells.}

CORRECT ANSWER: “B” 

Prokaryotic cells are much smaller and more simple than eukaryotic cells. This means that it takes less time for the genetic information in prokaryotes to copy and divide.

300

Which membrane-bound organelle is found in plant cells, but not animal cells?

(A) Lysosomes

(B) Mitochondria

(C) Vacuoles

(D) Chloroplasts

CORRECT ANSWER "D" CHLOROPLASTS

^{Plants use chloroplasts to perform photosynthesis. Animals do not need chloroplasts because they get sugar from eating food, not from sunlight.}

400

Protein synthesis can occur on the rough endoplasmic reticulum (ER) but not on the smooth ER. Which cell structures are attached to the surface of the rough ER that allow it to make proteins?

^{(A) Chloroplasts}

^{(B) DNA strands}

^{(C) Vacuoles}

^{(D) Ribosomes}

CORRECT ANSWER: “D” RIBOSOMES

^{The rough ER is studded with ribosomes. Because ribosomes make proteins, the rough ER acts as a site for protein synthesis.}

500

What property makes phospholipids ideal building blocks for cell membranes?

^{(A) They have hydrophilic heads and hydrophobic tails.}

^{(B) They have hydrophilic heads and tails.}

^{(C) They have hydrophobic heads and tails.}

^{(D) They have hydrophobic heads and hydrophilic tails.}

THE ANSWER IS: "A" They have hydrophilic heads and hydrophobic tails.

Phospholipids have hydrophilic heads and hydrophobic tails. The hydrophilic heads face outward, and the hydrophobic tails face inward.

Evolution

100

Which of the following is true regarding Darwin's theory of evolution?

^{(A) Acquired traits are always passed on to offspring.}

^{(B) Organisms develop favorable adaptations based on a need.}

^{(C) Individuals pass on adaptations to their offspring, due to natural selection.} 

^{(D) Pure chance determines which species evolve.}

CORRECT ANSWER: “C” 

^{Darwin's theory proposed that organisms with heritable traits that favor survival and reproduction will tend to leave more offspring than their peers. This causes the traits to increase in frequency over generation.}

200

Which of the following best describes a difference between artificial and natural selection?

^{(A) Natural selection involves selective breeding while artificial selection does not.}

^{(B) Natural selection leads to lower fitness over time, while artificial selection improves fitness of the selected group.}

^{(C) Only artificial selection leads to evolution.}

^{(D) Natural selection leads to greater fitness over time, while artificial selection has no (or sometimes a damaging) effect on fitness.}

CORRECT ANSWER: "D"

^{In natural selection, favorable traits are selected for, allowing certain organisms to survive and reproduce. In artificial selection, humans selectively breed organisms for particular (and not necessarily fit) traits.}

300

Over years of selective breeding, French bulldogs have developed extremely short snouts and flat faces. These traits, although attractive to the dog owners, can make it difficult for the dogs to breathe. Which of the following processes led to the presence of these traits?

_{(A) Environmental Selection}

_{(B) Artificial Selection}

_{(C) Natural Selection}

_{(D) Sexual Selection}

CORRECT ANSWER: “B” ARTIFICIAL SELECTION

^{In artificial selection, humans selectively breed organisms for particularly desired (and not necessarily fit) traits.}

400

Koalas have come close to extinction due to hunting and disease. The current koala populations have very little genetic diversity. Which of the following is a likely result of the low genetic variation in the current koala populations?

^{(A) The current koala population is less likely to be inbred.}

^{(B) Koalas in current populations are more resistant to new diseases.}

^{(C) Koalas in current populations are no longer able to successfully breed with other species.}

^{(D) The current koala populations are less likely to be able to adapt to environmental changes.}

CORRECT ANSWER: “D”

^{Low genetic variation makes a population less adaptable to change because the individuals are all genetically similar.}

500

Horses that have been bred by humans in captivity have more variation of coat colors than wild horses. What process most likely led to the greater coat color variation in domestic horses?

^{(A) Inbreeding} 

^{(B) Artificial Selection}

^{(C) Cloning} 

^{(D) Natural Selection}

CORRECT ANSWER: “B” ARTIFICIAL SELECTION

^{Humans selectively bred horses for colors that they liked, increasing the diversity of coat colors seen in domestic horses.}

Human Body

100

What is one of the functions of the human skeleton?

^{(A) Producing blood cells}

^{(B) Breaking down nutrients}

^{(C) Releasing hormones}

^{(D) Obtaining oxygen}

CORRECT ANSWER: “A” Producing blood cells

^{Red and white blood cells are produced in the marrow of some bones}

200

Which of the following is true regarding the large intestine?

^{(A) It contains salivary glands, which secrete amylase.}

^{(B) Most chemical digestion occurs there.}

^{(C) It is the major site of water absorption.}

^{(D) It is four times as long as the small intestine.}

CORRECT ANSWER: “C”

^{The large intestine absorbs any excess water that is not absorbed by small intestine.}

300

What structure removes excess water, urea, and metabolic waste from blood?

^{(A) Urinary bladder}

^{(B) Kidney}

^{(C) Urethra}

^{(D) Ureter}

CORRECT ANSWER: “B” KIDNEY

The kidneys filter blood using their structural units, nephrons.

400

Choking can cause asphyxiation, a state in which the body is severely deprived of oxygen. Which of the following answer choices correctly describes how asphyxiation could ultimately lead to death?

^{(A) Due to choking, the circulatory system would be unable to get oxygen into the body.}

^{(B) The respiratory system would be unable to deliver oxygen to areas of the body that need it, such as the brain.}

^{(C) Due to choking, the respiratory system would be unable to get oxygen into the body.}

^{(D) The circulatory system would be unable to deliver oxygen to areas of the body that need it, such as the brain.}

CORRECT ANSWER: BOTH “C” AND “D” OR “C” OR “D”

^{(C) When the flow of oxygen into the body is blocked, the body cannot convert deoxygenated blood to oxygenated blood at the lungs. In turn, blood will permanently remain in a deoxygenated state.}

^{(D) When oxygenated blood cannot be properly delivered, all cells in the body that rely on a constant supply of oxygen in order to function will die, ultimately causing entire organs and systems to asphyxiate}

500

Which statement correctly orders the events of a muscle contraction after a nerve signal has been received?

^{(A) Myosin filaments are stimulated, pulling on the sarcomere, and shortening the actin.}

^{(B) Myosin filaments are stimulated, pulling on actin and shortening the sarcomere.}

^{(C) Actin filaments are stimulated, pulling on myosin, and shortening the sarcomere.}

^{(D) Actin filaments are stimulated, pulling on the sarcomere, and shortening the myosin.}

CORRECT ANSWER: “B” Myosin filaments are stimulated, pulling on actin and shortening the sarcomere.

^{When a nerve signal reaches the neuromuscular junction, it stimulates the myosin filaments to pull on the actin, shortening the sarcomere, causing the muscle to contract.}

Ecology

100

^{A food chain is represented below.}

Phytoplankton ⟶ Krill ⟶ Mackerel ⟶ Sea gull

Which organism in the food chain is a producer?

^{(A) Phytoplankton}

^{(B) Mackerel}

^{(C) Sea gull}

^{(D) Krill}

CORRECT ANSWER: “A” PHYTOPLANKTON

^{The phytoplankton is a producer, beginning the energy flow of the food chain.}

200

Which of the following human actions could have a positive impact on local ecosystems?

^{(A) Producing waste during technology development}

^{(B) Increasing the use of pesticides to protect crops}    

^{(C) Clearing forests to make way for new farms}

^{(D) Using renewable resources} 

CORRECT ANSWER: “D” USING RENEWABLE RESOURCES

^{The use of renewable resources reduces greenhouse gas emissions and decreases pollution.}

300

A cuckoo bird lays its eggs in a warbler bird's nest. Once hatched, the cuckoo chicks displace the warbler chicks, tricking the parent warbler into caring for them over their own young. What type of ecological interaction does the cuckoo have with the warbler?

^{(A) Mutualism}

^{(B) Parasitism}

^{(C) Commesalism}

^{(D) Predation}

CORRECT ANSWER: “B” PARASITISM

^{In this case, the cuckoo (parasite) is the species that benefits and the warbler (host) is harmed.}

400

Which of the following factors can be representative of a population near carrying capacity?

^{(A) An increase in resource competition}

^{(B) An increase in offspring survival rate}

^{(C) An increase in younger population members}

^{(D) An increased ratio of birthrate to death rate}

CORRECT ANSWER: “A” An increase in resource competition

^{When a population is reaching the limit of its resources, the competition for those resources increases, slowing down the growth of the population.}

500

An isolated bird population on a remote island remains at a relatively constant size year after year. Which of the following most likely describes the birthrate and the death rate for this population?

^{(A) Birthrate and death rate are close to equal.}

^{(B) Birthrate is significantly greater than death rate.}

^{(C) Birthrate is significantly lower than death rate.}

^{(D) Birthrate and death rate are both zero.}

CORRECT ANSWER: “A” Birthrate and death rate are close to equal.

^{When birthrate and death rate are equivalent, the population size doesn't appear to change.}

Random

100

Which structure is the site of protein synthesis in the cell?

(A) Cell membrane

(B) Cytosol

(C) Ribosome

(D) Flagellum 

CORRECT ANSWER: “C” RIBOSOME

Ribosomes are small, round structures that act as the location for protein synthesis.

200

What is a primary function of the respiratory system?

^{(A) To provide protection of internal organs}

^{(B) To acquire oxygen from the atmosphere}

^{(C) To carry oxygen throughout blood vessels}

^{(D) To regulate body processes through hormone production}

CORRECT ANSWER: “B” TO ACQUIRE OXYGEN FROM THE ATMOSPHERE

^{One role of the respiratory system is to bring oxygenated air into the body.}

300

A genetic mutation causes a snake to have brown skin. After many generations, most of the snake population has the brown skin mutation.Which of the following most likely caused this change?

^{(A) Snakes with the brown skin mutation are able to survive and reproduce more successfully than snakes without it.}

^{(B) All the snakes in the area were infected with the mutation.}

^{(C) The other snakes changed their colors to mimic the brown snake.}

^{(D) The same mutation occurred in other snakes in response to environmental conditions.}

CORRECT ANSWER: “A”

The snake likely passed its brown skin mutation on to its offspring. These offspring had a fitness advantage over snakes without the mutation, allowing them to survive and reproduce better.

400

Which of the following answer choices correctly sequences the path of urination in the body?

^{(A) Blood enters nephron, filtration, reabsorption, excretion through urethra}

^{(B) Blood enters nephron, filtration, reabsorption, excretion through ureturs}

^{(C) Flitration, reabsorption, blood enters nephron, excretion through urethra} 

^{(D) Blood enters nephron, reabsorption, filtration, excretion, through urethra}

CORRECT ANSWER: “A” The pathway of urination is blood entering the nephron, filtration, reabsorption, and finally, excretion through the urethra.

500

A volcanic eruption makes a local island completely devoid of life. Over the next few years, some small lichens began to colonize the remaining rock and soil. This is an example of which of the following?

^{(A) Primary Sucession}

^{(B) Secondary Succesion}

^{(C) Natural Selection}

^{(D) Climax Community}

CORRECT ANSWER: “A” PRIMARY SUCCESSION

^{Primary succession occurs when new land is formed or bare rock is exposed, providing a habitat that can be colonized for the first time.}