1.
Most of the energy used by life on Earth comes from the
Correct Answer
D. Sun
Explanation
The sun is the primary source of energy for life on Earth through a process called photosynthesis. Plants and other photosynthetic organisms convert sunlight into chemical energy, which is then used by other organisms in the food chain. The sun's energy also drives weather systems, which play a crucial role in the distribution of heat and moisture on Earth. The rotation of the Earth and the moon have negligible direct impact on the energy used by life on Earth compared to the sun.
2.
Where do plants get the carbon dioxide needed for photosynthesis
Correct Answer
B. Air
Explanation
Plants get the carbon dioxide needed for photosynthesis from the air. During photosynthesis, plants take in carbon dioxide from the atmosphere through tiny pores called stomata on their leaves. This carbon dioxide is then used along with sunlight and water to produce glucose, which is the main source of energy for the plant. Therefore, the correct answer is air.
3.
Chlorophyll is green because
Correct Answer
B. It reflects green wavelengths of light
Explanation
Chlorophyll is green because it reflects green wavelengths of light. When light hits chlorophyll molecules, they absorb certain wavelengths of light, such as blue and red, but reflect green light. This reflected green light is what we perceive as the color green.
4.
Cellular respiration occurs in
Correct Answer
C. Animals and plants
Explanation
Cellular respiration is the process by which cells convert glucose and oxygen into energy, carbon dioxide, and water. It occurs in both animals and plants as they both require energy to carry out their metabolic functions. Animals use cellular respiration to produce energy for movement, growth, and other physiological processes. Plants use cellular respiration during the night or in the absence of sunlight when they cannot perform photosynthesis to produce energy. Therefore, cellular respiration occurs in both animals and plants.
5.
Light energy is converted to chemical energy through the process of
Correct Answer
A. pHotosynthesis
Explanation
Photosynthesis is the process by which plants convert light energy into chemical energy in the form of glucose. During photosynthesis, plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. This process occurs in the chloroplasts of plant cells and is essential for the survival of plants and the production of oxygen in the atmosphere. Glycolysis, cellular respiration, and fermentation are not involved in the conversion of light energy to chemical energy.
6.
Which of the following do not carry out photosynthesis?
Correct Answer
D. Animals
Explanation
Animals do not carry out photosynthesis. Photosynthesis is the process by which plants, certain prokaryotes, and algae convert sunlight into energy by producing glucose and oxygen. Animals, on the other hand, do not possess the necessary organelles, such as chloroplasts, to carry out photosynthesis. Instead, animals obtain energy by consuming other organisms or organic matter. Therefore, animals rely on plants and other photosynthetic organisms for their energy requirements.
7.
Plants produce what two products in photosynthesis?
Correct Answer
B. Oxygen and glucose
Explanation
During photosynthesis, plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. The sunlight is absorbed by chlorophyll in the plant's cells, which converts carbon dioxide and water into glucose, a form of sugar that plants use for energy. Oxygen is released as a byproduct of this process and is then released into the atmosphere. Therefore, the correct answer is oxygen and glucose.
8.
Plant cells have
Correct Answer
C. Both mitochondria and chloroplasts
Explanation
Plant cells have both mitochondria and chloroplasts. Mitochondria are responsible for producing energy through cellular respiration, while chloroplasts are responsible for photosynthesis, converting sunlight into energy. Both organelles play crucial roles in the cell's energy production and metabolism. Mitochondria provide the cell with ATP, the energy currency of the cell, while chloroplasts enable plants to produce their own food through photosynthesis. Therefore, plant cells require both mitochondria and chloroplasts to carry out their essential functions.
9.
Where does cellular respiration occur?
Correct Answer
A. In mitochondria
Explanation
Cellular respiration is the process by which cells convert glucose into energy in the form of ATP. This process occurs in the mitochondria, which are known as the "powerhouses" of the cell. Mitochondria have a highly folded inner membrane that provides a large surface area for the various reactions involved in cellular respiration. This allows for the efficient production of ATP through the breakdown of glucose and the transfer of electrons in a series of chemical reactions known as the electron transport chain. Therefore, the correct answer is "in mitochondria."
10.
What is ATP?
Correct Answer
D. An energy source for both plants and animals
Explanation
ATP (adenosine triphosphate) is a molecule that serves as the primary energy source for both plants and animals. It is produced during cellular respiration and is used by cells to fuel various biological processes, such as muscle contraction, active transport, and chemical synthesis. ATP is often referred to as the "energy currency" of cells because it can be easily broken down to release energy when needed and then quickly regenerated to store energy again. Therefore, it is an essential molecule for all living organisms, providing the energy required for their metabolic activities.
11.
An example of an autotroph is
Correct Answer
C. A tree
Explanation
Autotrophs are organisms that can produce their own food using energy from sunlight or inorganic substances. They are capable of photosynthesis or chemosynthesis. In this case, a tree is the correct answer because trees are able to use sunlight and convert it into energy through photosynthesis. They can produce their own food in the form of glucose, which allows them to grow and survive. Dogs, cats, and humans are not autotrophs as they cannot produce their own food and rely on consuming other organisms for energy.
12.
Which pigment reflects green light and absorbs the other colors of light to provide energy forphotosynthesis?
Correct Answer
A. ChloropHyll
Explanation
Chlorophyll is the pigment that reflects green light and absorbs other colors of light for photosynthesis. It is responsible for capturing light energy and converting it into chemical energy during the process of photosynthesis. Chlorophyll is found in the chloroplasts of plant cells and is essential for the synthesis of glucose and oxygen. Carotenoids, thylakoids, and chloroplasts are not directly involved in reflecting green light and absorbing other colors of light for photosynthesis.
13.
Which pigment reflects orange, yellow, and red light and absorbs the other colors to provide energy for photosynthesis?
Correct Answer
B. Carotenoids
Explanation
Carotenoids are pigments that reflect orange, yellow, and red light, while absorbing other colors. These pigments are found in chloroplasts, which are the organelles responsible for photosynthesis in plant cells. Carotenoids play an important role in capturing light energy and transferring it to chlorophyll molecules, which then use this energy to drive the process of photosynthesis. Therefore, carotenoids absorb the other colors of light to provide energy for photosynthesis.
14.
Where are the pigments located in the chloroplast?
Correct Answer
A. In the thylakoid
Explanation
The pigments are located in the thylakoid of the chloroplast. Thylakoids are membrane-bound compartments within the chloroplast where photosynthesis takes place. They contain the photosynthetic pigments, such as chlorophyll, that absorb light energy and convert it into chemical energy. These pigments are essential for capturing sunlight and initiating the process of photosynthesis.
15.
Photosynthesis takes what 3 things to create energy?
Correct Answer
A. Carbon dioxide, water, and energy
Explanation
Photosynthesis is the process by which plants convert carbon dioxide and water into glucose and oxygen using sunlight as an energy source. Therefore, the correct answer is carbon dioxide, water, and energy.
16.
An example of a heterotroph is
Correct Answer
C. A bunny
Explanation
A heterotroph is an organism that obtains its food by consuming other organisms. Grass and a flower are examples of autotrophs, as they can produce their own food through photosynthesis. A bush is a vague term that does not specify the type of organism. On the other hand, a bunny is a clear example of a heterotroph as it relies on consuming plants or other organisms for its nutrition.
17.
The part of photosynthesis that does not require light is known as
Correct Answer
A. The Calvin Cycle
Explanation
The Calvin Cycle is the correct answer because it is the part of photosynthesis that occurs in the stroma of chloroplasts and does not require light. It involves a series of chemical reactions that convert carbon dioxide into glucose, utilizing the energy stored in ATP and NADPH molecules produced during the light-dependent reactions. The Calvin Cycle is essential for the synthesis of sugars and other organic compounds in plants. The Krebs Cycle, on the other hand, is a part of cellular respiration and not photosynthesis. The Darwin Cycle and the Hooke Cycle are not recognized terms in the context of photosynthesis.
18.
What is the role of NADpH in photosynthesis?
Correct Answer
D. Storing energy
Explanation
NADPH is a molecule that plays a crucial role in photosynthesis by storing energy. During the light-dependent reactions of photosynthesis, NADPH is produced by capturing and storing the energy from sunlight. This energy is then utilized in the light-independent reactions to convert carbon dioxide into glucose, a process known as the Calvin cycle. NADPH acts as an energy carrier, providing the necessary energy for the synthesis of glucose and other organic molecules. Therefore, it is responsible for storing the energy that is used to fuel the various metabolic processes in plants.
19.
What is the name of the sugar that is formed during photosynthesis?
Correct Answer
C. Glucose
Explanation
Glucose is the correct answer because it is the sugar that is formed during photosynthesis. Photosynthesis is the process by which plants convert sunlight, water, and carbon dioxide into glucose and oxygen. Glucose is a simple sugar that serves as an important source of energy for plants and is also used in various metabolic processes.
20.
Which of the following is a factor that can affect photosynthesis?
Correct Answer
C. Too much sun
Explanation
Too much sun can affect photosynthesis because excessive sunlight can lead to an increase in temperature, causing the plant's enzymes to denature. This can disrupt the chemical reactions involved in photosynthesis, reducing the efficiency of the process. Additionally, intense sunlight can also cause damage to the chlorophyll pigments, which are responsible for capturing light energy. As a result, the plant may not be able to effectively convert sunlight into chemical energy, impacting its ability to produce glucose through photosynthesis.
21.
What is the term used for the metabolic pathway in which glucose (C6H12O6) is degraded to carbon dioxide (CO2) and water?
Correct Answer
A. Cellular respiration
Explanation
Cellular respiration is the correct answer because it is the metabolic pathway in which glucose is broken down to produce energy in the form of ATP. This process occurs in the presence of oxygen and involves several stages, including glycolysis, the citric acid cycle, and oxidative phosphorylation. Through cellular respiration, glucose is ultimately converted into carbon dioxide and water, releasing energy that can be used by the cell.
22.
In addition to ATP, what are the end products of glycolysis?
Correct Answer
C. NADH and pyruvate
Explanation
During glycolysis, glucose is broken down into two molecules of pyruvate. At the same time, NAD+ is reduced to NADH. Therefore, the end products of glycolysis are NADH and pyruvate. CO2 and H2O are not end products of glycolysis, but rather the products of cellular respiration that occurs after glycolysis.
23.
Cellular respiration harvests the most chemical energy from which of the following?
Correct Answer
B. Chemiosmotic pHospHorylation
Explanation
Chemiosmotic phosphorylation is the process by which ATP is generated in cellular respiration. It involves the movement of protons across a membrane, creating an electrochemical gradient. This gradient is then used by ATP synthase to produce ATP. This process is highly efficient and produces the most chemical energy compared to substrate-level phosphorylation, converting oxygen to ATP, or generating carbon dioxide and oxygen in the electron transport chain. Therefore, chemiosmotic phosphorylation is the correct answer.
24.
Where are the proteins of the electron transport chain located?
Correct Answer
C. Mitochondrial inner membrane
Explanation
The proteins of the electron transport chain are located in the mitochondrial inner membrane. This membrane is highly specialized and contains the respiratory complexes that carry out the electron transport chain reactions. The inner membrane is impermeable to ions and small molecules, allowing for the establishment of an electrochemical gradient that is crucial for ATP synthesis. Therefore, the correct answer is mitochondrial inner membrane.
25.
The primary role of oxygen in cellular respiration is to
Correct Answer
B. Act as an acceptor for electrons and hydrogen, forming water.
Explanation
Oxygen acts as an acceptor for electrons and hydrogen, forming water, in cellular respiration. During the process of cellular respiration, glucose is broken down to release energy. This energy is stored in the form of ATP. Oxygen plays a crucial role in the final step of cellular respiration, which is the electron transport chain. In this step, electrons and hydrogen ions are transferred to oxygen, forming water. This process allows for the production of ATP, the energy currency of the cell. Therefore, the primary role of oxygen in cellular respiration is to act as an acceptor for electrons and hydrogen, forming water.
26.
Which of the following statements is (are) correct about an oxidation-reduction (or redox) reaction?
Correct Answer
D. Both A and B are correct.
Explanation
In an oxidation-reduction (or redox) reaction, the molecule that is reduced gains electrons. This is because reduction involves the gain of electrons, which results in a decrease in the oxidation state of the molecule. On the other hand, the molecule that is oxidized loses electrons. This is because oxidation involves the loss of electrons, which leads to an increase in the oxidation state of the molecule. Therefore, both statements A and B are correct.
27.
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?
Correct Answer
B. Glycolysis
Explanation
Glycolysis is the process in eukaryotic cells that can proceed normally whether oxygen is present or absent. It is the initial step of cellular respiration and occurs in the cytoplasm. During glycolysis, glucose is broken down into pyruvate molecules, producing a small amount of ATP and NADH. This process does not require oxygen and can occur under anaerobic conditions. In the absence of oxygen, pyruvate can then be converted into lactate or ethanol, depending on the organism. Therefore, glycolysis is the correct answer as it is not dependent on the presence of oxygen.
28.
All of the following are functions of the citric acid cycle except
Correct Answer
D. Adding electrons and protons to oxygen, forming water.
Explanation
The citric acid cycle, also known as the Krebs cycle, is a series of chemical reactions that occur in the mitochondria of cells. Its main function is to generate energy in the form of ATP through a process called oxidative phosphorylation. During the cycle, NADH is produced, which is an electron carrier that plays a crucial role in the electron transport chain. Additionally, carbon dioxide is released as a byproduct. However, the citric acid cycle does not directly involve the addition of electrons and protons to oxygen to form water. This process occurs in the electron transport chain, which is the next step in cellular respiration.
29.
What is the primary function of the Calvin cycle?
Correct Answer
D. Synthesize simple sugars from carbon dioxide
Explanation
The primary function of the Calvin cycle is to synthesize simple sugars from carbon dioxide. This process occurs in the stroma of the chloroplasts and is also known as carbon fixation. During the Calvin cycle, ATP and NADPH produced in the light-dependent reactions are used to convert carbon dioxide into glucose or other carbohydrates. This process is essential for plants to produce energy-rich molecules that can be used for growth and other metabolic processes.
30.
Which of the following statements best describes the relationship between photosynthesis and respiration?
Correct Answer
B. pHotosynthesis stores energy in complex organic molecules, while respiration releases it.
Explanation
Photosynthesis and respiration are two interconnected processes in living organisms. Photosynthesis is the process by which plants convert sunlight into energy and store it in the form of complex organic molecules such as glucose. On the other hand, respiration is the process by which organisms release the stored energy from these complex organic molecules, such as glucose, and convert it into a usable form called ATP. Therefore, the statement "Photosynthesis stores energy in complex organic molecules, while respiration releases it" accurately describes the relationship between photosynthesis and respiration.
31.
Earth is said to be a little over 4.5 billion years old.
Correct Answer
A. True
Explanation
The age of the Earth is estimated to be around 4.5 billion years old based on scientific evidence such as radiometric dating of rocks and meteorites. This method involves measuring the decay of radioactive isotopes in these materials to determine their age. Additionally, other geological and astronomical data also support this estimate. Therefore, the statement that the Earth is a little over 4.5 billion years old is true.
32.
About 3.8 billion years ago, life on Earth initially began with single-celled eukaryotic cells.
Correct Answer
B. False
Explanation
Life on Earth did not initially begin with single-celled eukaryotic cells about 3.8 billion years ago. The earliest forms of life on Earth were actually prokaryotic cells, which are simpler and lack a nucleus. Eukaryotic cells, which contain a nucleus and other membrane-bound organelles, evolved much later in the history of life on Earth. Therefore, the statement is false.
33.
Most creationists believe that the current form of species is the same as the original form that God created.
Correct Answer
A. True
Explanation
This statement aligns with the belief of creationists who hold that the current form of species is identical to the original form created by God. They reject the idea of evolution and believe that all species were created in their present form. Therefore, the statement is true according to creationist beliefs.
34.
The theory of abiogenesis states that living things were naturally created from nonliving things such as simple inorganic compounds.
Correct Answer
B. False
Explanation
The theory of abiogenesis suggests that living things were not naturally created from nonliving things such as simple inorganic compounds. Instead, it proposes that life originated from preexisting living organisms. This theory is supported by scientific evidence and experiments that demonstrate the process of biogenesis, where living organisms arise from other living organisms. Therefore, the statement is false.
35.
Louis Pasteur argued that life comes from preexisting life and not from nonliving material.
Correct Answer
A. True
Explanation
Louis Pasteur argued that life comes from preexisting life and not from nonliving material. This is known as the principle of biogenesis. Pasteur conducted experiments that disproved the theory of spontaneous generation, which proposed that living organisms could arise spontaneously from nonliving matter. His experiments involved sterilizing broth in flasks and then observing that no growth occurred unless the flasks were exposed to air containing living organisms. These experiments provided strong evidence for the concept of biogenesis and supported the idea that life can only arise from preexisting life.
36.
Theory of Catastrophism states that there have been several living creations from God, each encountered a catastrophe, which completely destroyed them.
Correct Answer
A. True
Explanation
The explanation for the given correct answer is that the Theory of Catastrophism proposes that multiple living creations by God have experienced catastrophic events that led to their complete destruction. This theory suggests that these catastrophes played a significant role in shaping the Earth's history and the diversity of life on it. Therefore, the statement is true as it aligns with the Theory of Catastrophism.
37.
Essential chemical reactions in life can be best described as building up (catabolism) and breaking down (anabolism) processes.
Correct Answer
B. False
Explanation
Essential chemical reactions in life can be best described as catabolic and anabolic processes. Catabolic reactions involve breaking down larger molecules into smaller ones, releasing energy in the process. Anabolic reactions, on the other hand, involve building up smaller molecules into larger ones, requiring energy input. Therefore, the statement that essential chemical reactions in life can be best described as building up and breaking down processes is true, not false.
38.
Most living things such as animals and plants are unicellular organisms.
Correct Answer
B. False
Explanation
The statement is incorrect. Most living things such as animals and plants are multicellular organisms, meaning they are made up of multiple cells. Unicellular organisms, on the other hand, consist of only one cell. Therefore, the correct answer is False.
39.
Interaction among organisms is simultaneously happening on Earth; no individual species is truly alone.
Correct Answer
A. True
Explanation
The statement suggests that organisms on Earth are constantly interacting with each other, indicating that no species exists in isolation. This implies that all organisms are interconnected and rely on each other in some way for survival or other purposes. Therefore, the correct answer is true.
40.
Humans have an average life expectancy of 60 to 70 years, while some plants can live far more than a hundred year.
Correct Answer
A. True
Explanation
The statement is true because it states that humans have an average life expectancy of 60 to 70 years, which is generally accepted as accurate. It also mentions that some plants can live far more than a hundred years, which is also true as there are several plant species that have been known to live for centuries. Therefore, the statement is correct.
41.
The ability of living things to produce offspring of its own kind is called reproduction.
Correct Answer
A. True
Explanation
Reproduction refers to the ability of living organisms to produce offspring of their own kind. It is a fundamental characteristic of living things and is essential for the continuation of a species. Through reproduction, organisms pass on their genetic material to the next generation, ensuring the survival and diversity of life on Earth. Therefore, the statement "The ability of living things to produce offspring of its own kind is called reproduction" is true.
42.
Many organisms become extinct because they are unable to reproduce their own kind.
Correct Answer
A. True
Explanation
Many organisms become extinct because they are unable to reproduce their own kind. This is true because reproduction is essential for the survival and continuation of a species. If organisms are unable to reproduce, either due to reproductive disorders, environmental changes, or other factors, their population will decline and eventually become extinct. Reproduction ensures the genetic diversity and adaptation of a species, allowing it to survive and thrive in changing environments. Without successful reproduction, a species cannot sustain itself, leading to its extinction.
43.
Other simple organisms, such as bacteria and plants, can reproduce sexually.
Correct Answer
B. False
Explanation
The statement in the question is false. Bacteria reproduce asexually through binary fission, where one cell divides into two identical cells. Plants, on the other hand, have the ability to reproduce both sexually and asexually. They can reproduce sexually through the process of pollination and fertilization, but they can also reproduce asexually through methods like vegetative propagation. Therefore, the correct answer is false.
44.
Evolution is the gradual change in organisms over a short period of time in response to the changing environment.
Correct Answer
B. False
Explanation
Evolution is not a gradual change in organisms over a short period of time, but rather a slow process that occurs over long periods of time, often spanning thousands or millions of years. It involves the accumulation of genetic changes in populations of organisms, leading to the development of new species. Therefore, the statement that evolution is a gradual change over a short period of time is incorrect.
45.
Adaptation is any response or reaction towards a stimulus that helps in the survival of an organism.
Correct Answer
A. True
Explanation
Adaptation refers to the ability of an organism to adjust to its environment in order to enhance its chances of survival. It involves responses or reactions to stimuli that promote the organism's well-being and enable it to thrive in its surroundings. Therefore, the statement "Adaptation is any response or reaction towards a stimulus that helps in the survival of an organism" is true, as it accurately describes the concept of adaptation.
46.
All living things exhibit organization, whether they are unicellular or multicellular organisms.
Correct Answer
A. True
Explanation
Living things exhibit organization because they are made up of cells, which are the basic units of life. These cells work together to form tissues, organs, and organ systems, allowing for specialized functions and efficient processes within the organism. This organization is essential for the survival and functioning of living things, regardless of whether they are unicellular or multicellular. Therefore, the statement "All living things exhibit organization, whether they are unicellular or multicellular organisms" is true.
47.
In multicellular organisms like plants and animals, cells are grouped as tissues to perform a specific functions.
Correct Answer
A. True
Explanation
In multicellular organisms, cells are organized into tissues to carry out specialized functions. This allows for division of labor and efficient functioning of the organism as a whole. Tissues are made up of cells that are similar in structure and function, working together to perform specific tasks such as transport, protection, or secretion. This organization is essential for the proper functioning and survival of complex organisms. Therefore, the statement "In multicellular organisms like plants and animals, cells are grouped as tissues to perform specific functions" is true.
48.
Prolonged adaptation to certain environments may lead to the gradual evolution of the succeeding generations.
Correct Answer
A. True
Explanation
Prolonged adaptation to certain environments can result in the gradual evolution of succeeding generations. This means that over time, individuals who are better suited to their environment are more likely to survive and reproduce, passing on their advantageous traits to their offspring. This process, known as natural selection, can lead to the development of new species or the modification of existing ones. Therefore, the statement is true.
49.
The discovery of the cell is largely attributed to Charles Darwin.
Correct Answer
B. False
Explanation
The statement is false because the discovery of the cell is not attributed to Charles Darwin. The cell was actually discovered by Robert Hooke in 1665 when he observed cork under a microscope and noticed small compartments that he called "cells." Charles Darwin, on the other hand, is known for his contributions to the theory of evolution through natural selection.
50.
Human sexual reproduction occurs when a female gamete is fertilized by a male gamete to form a zygote which will develop and became an embryo.
Correct Answer
A. True
Explanation
Human sexual reproduction involves the fusion of a female gamete (egg) and a male gamete (sperm) to form a zygote. This zygote then undergoes further development and becomes an embryo. This process is essential for the continuation of the human species and is true for human sexual reproduction.