Science

Science

100

All of the following may inhibit enzymatic reactions EXCEPT (A) temperature (B) pH level (C) excess of substrate (D) lack of substrate

C) excess of substrate Environmental conditions such as heat or acidity inhibit enzymatic reactions by chang- ing the shape of the active site and rendering the enzyme ineffective. Certain chemicals inhibit enzymatic reactions by changing the shape of the enzyme’s active site. If there is a lack of substrate, the enzyme will have no substance to affect. Thus, all of these factors may inhibit enzymatic reactions except an excess of substrate, which would not inhibit those reactions.

200

Mass times acceleration (A) Gravity (B) Force (C) Inertia (D) Momentum

(B) Force Force equals mass times acceleration.

300

Astronomers observing the redshift of light from a faraway star means that the star is (A) moving away from us (B) moving toward us (C) ready to explode (D) a dwarf star

A) moving away from us A redshift in the electromagnetic spectrum of the light from a faraway star means that the star is moving away from the observer. In the 1920s, Edwin Hubble (1889–1953) observed that galaxies around the Milky Way were moving away from us because of this redshift, and those farther away are moving away from us even more rapidly; it is not mov- ing toward us.

400

The respiration reaction shown below and that occurs at night is a _______________ reaction. This would be a drop-down question type on the GED® test. (A) decomposition (B) combination (C) replacement (D) double replacement

(A) The respiration reaction discussed in the paragraph is an exothermic reaction, releasing energy for the cell’s use. It is also a decomposition reaction rather than a combination or replacement reaction.

500

What percentage of the offspring of two albino parents would most likely be normal? (A) 100% (B) 50% (C) 10% (D) 0%

(D) All offspring of two albino parents (each must have the genotype nn) will be albino, so the answer is 0%.

Science

100

All of the following are steps of photosynthesis EXCEPT (A) Chlorophyll is absorbed through plant roots. (B) During photolysis a photon of light is absorbed by the chlorophyll pigment, which then is in an excited (higher energy) state. (C) Water is separated into hydrogen and oxygen atoms. (D) An ADP molecule is phosphorylated to ATP.

(A) Chlorophyll is absorbed through plant roots. Chlorophyll is not absorbed through plant roots; it is synthesized within plant cells. Photolysis, where a photon of light is absorbed by the chlorophyll pigment, which then is in an excited (higher energy) state, is the first step in the photosynthetic process. The light reaction is a decomposition reaction that separates water molecules into hydrogen and oxygen atoms utilizing the energy from the excited chlorophyll pigment. Oxygen that is not needed by the cell combines to form O2 (gas) and is released into the environment. The free hydrogen is grabbed and held by a particular molecule (called the hydrogen acceptor) until it is needed.

200

Acts at a distance and attracts bodies of matter toward each other (A) Gravity (B) Force (C) Inertia (D) Momentum

A) Gravity Gravity is defined as the force that acts at a distance and attracts bodies of matter toward each other.

300

Rabbits are not native to Australia, having been brought there from England by sailors in the 18th century. Yet rabbits have thrived and have in fact overpopulated Australia. In addition, rabbits and certain native Australian wallabies, although not closely related, resemble each other as to body structure and habits. Which idea about evolution is supported by these facts? (A) Mass extinctions of species and the emergence of new species can be studied by examining the fossil record. (B) Different species originally developed because of changes in some shared ances- tral genetic code. (C) Many species have body parts that look similar because they evolved from the same ancestral mammal. (D) Species evolve in similar ways when they react to similar surroundings.

(D) Though rabbits and wallabies are not closely related and their geographic origins are distant, their similarities and the rabbits ability to survive in similar habitat supports the idea that widely divergent species can evolve in similar ways when reacting to similar bio- geographical environments.

400

Considering the paragraph and the graph, explain what effect shortening days of sun- light in winter would have on the pond ecosystem.

[3 pts possible] As the amount of daylight per day decreases in autumn and winter there is less photosynthesis and more respiration. (1 pt) The oxygen levels in the pond will decrease and the pond will not be able to support as many fish. (1 pt) The population of fish will drop off until the sunlight begins to increase again. (1 pt)

500

What are the chances that two normal parents each carrying recessive genes for albinism could have a heterozygous normal offspring? (A) 1 out of 2 (B) 3 out of 4 (C) 2 out of 3 (D) 0 out of 4

(A) Referring to the Punnett square in answer 22, it is clear that the Nn × Nn cross would yield 1 out of 4 albino (homozygous), 1 out of 4 homozygous normal (NN), and 2 out of 4 heterozygous normal (Nn) children.

Science

100

Which has the least mass? (A) Proton (B) Neutron (C) Electron (D) Hydrogen atom

(C) Electron An electron has nearly no discernible mass. A proton has a mass of 1 atomic mass unit (AMU) as does a neutron. According to the Periodic Table of Elements an atom of hydro- gen has a mass on average of 1AMU (1.007) since the most common isotope of hydrogen has no neutrons and is a single proton.

200

Mass times velocity (A) Gravity (B) Force (C) Inertia (D) Momentum

(D) Momentum Momentum is equal to mass times velocity.

300

An athlete with a sore shoulder places a warm compress on it to transfer energy to soothe the muscle. (A) Radiation (B) Convection (C) Irradiation (D) Conduction

(D) Conduction is the transfer of molecules by collisions, passing heat through one material into another.

400

Energy flows through the food chain from (A) producers to consumers to decomposers (B) producers to secondary consumers to primary consumers (C) decomposers to consumers to producers (D) secondary consumers to producers

(A) Energy flows through the entire ecosystem in one direction, from producers to consum- ers and on to decomposers through the food chain.

500

Which of the following chemical equations is NOT properly balanced? (A) FeCl3 – 3NaOH → Fe(OH)3 – 3NaCl (B) CH4 + O2 → CO2 + 2H2O (C) C3H3 + 5O2 → 3CO2 + 4H2O (D) 2NaCL + F2 → 2NAF + CL2

(B) The correct balanced equation is: CH4 + O2 → CO2 + 2H2O

Science

100

Most animals have internal or external skeletons for structure and support. Which of the following parts provide a similar function in plant cells? (A) Cytoplasm (B) Chloroplasts (C) Cell membranes (D) Cell walls

(D) Cell walls Rigid cell walls made of cellulose serve the same function of structure and support in plant cells as skeletons do in animals.

200

A particle at rest will stay at rest and a particle in motion will stay in motion until acted upon by an outside force. (A) Gravity (B) Force (C) Inertia (D) Momentum

(C) Inertia Inertia is the property of matter that allows a particle at rest to stay at rest and a particle in motion to stay in motion until acted upon by an outside force.

300

On a cold February morning, a blower system in a car warms up after several minutes and blows air through vents in the floor, dashboard, and windshield. Eventually, the driver is able to unbutton his coat and stay warm when the outside temperature is still 23°F. (A) Radiation (B) Convection (C) Irradiation (D) Conduction

(B) Convection is caused by the flow of heated liquid or gas through a volumetric medium.

400

Three offspring of two normal skinned parents have normal skin, but one is albino. Which of the following must be true? (A) One parent must have the NN genotype. (B) Both parents must have the NN genotype. (C) One parent must have the nn genotype. (D) Both parents must have the Nn genotype.

(D) As shown in the following Punnett square, the only way offspring could be albino is if each parent has at least one recessive gene for albinism. Since both have a normal pheno- type, both must have the Nn genotype. Each parent must also have one recessive allele for albinism in order to produce one nn child.

500

The _________ is the densest atmospheric layer, accounting for most of the mass of the atmosphere. It contains 99% of the water vapor found in the atmosphere. A. Stratoshere B. Troposphere C. Exosphere

B. The troposphere is the densest atmospheric layer, accounting for most of the mass of the atmosphere, it contains 99% of the water vapor found in the atmosphere.

Science

100

Pathogens in the form of airborne droplets are most likely to cause which of the follow- ing illnesses? (A) Throat infection (B) Stomach virus (C) AIDS (D) Malaria

(A) Throat infection A respiratory illness such as a throat infection is the most likely to be caused by patho- gens in airborne droplets spread by sneezing or coughing. A virus might be caught by surface contact; AIDs is a bloodborne disease and must be passed by direct blood contact; and malaria is spread by parasites such as the bite of a mosquito.

200

In glycolysis, a molecule of glucose is broken down into all of the following EXCEPT (A) pyruvic acid (B) ATP (C) CO2 (D) H+

(C) CO2 CO2 is not a product of glycolysis. Each molecule of glucose is broken down into two molecules of pyruvic acid (pyruvate), two ATP molecules, and two hydrogen atoms (attached to NADH, nicotinamide adenine dinucleotide).

300

Getting ready for a fall cruise inspires a young lady to spend a couple of weeks going to a local spa and reclining under a tanning lamp. However, such practices might result in dangerous overexposure to ultraviolet rays that can lead to cancer or premature aging of the skin. (A) Radiation (B) Convection (C) Irradiation (D) Conduction

(A) Radiation is waves traveling through space to transfer heat away from the energy source.

400

The albino offspring from the F1 generation described above produces one albino off- spring and one normal offspring in the F2 generation. What must be the genotype of the albino’s mate? (A) Either Nn or NN (B) Either Nn or nn (C) Nn (D) nn

(C) The albino parent from the F1 cross must have the nn genotype. As shown in the follow- ing Punnett square, if the mate was albino (nn) all the offspring would be albino, and if the mate was homozygous (NN) then all the offspring would be normal. In order to produce both phenotypes, the second parent must be heterozygous (Nn).

500

Which statement BEST describes how a large decrease in phytoplankton and marine algae would affect the ocean food web? (A) The effect would not be drastic since the organisms are so small. (B) The number of marine animals would decrease due to the decrease in producers. (C) The number of consumers in the food web would increase as the producers decrease. (D) The number of decomposers would increase as the phytoplankton and marine algae die.

B) The numbers of marine animals that are primary consumers in the ocean food web would decrease because of the decrease in phytoplankton and marine algae that they depend on. The small size of the organisms does not affect their importance to the ecosystem (A). The number of consumers would decrease, not increase, with the loss of microorganisms. Decomposers would also decrease due to the overall effect on the ocean food web.