Grade 10 Biology Test

1. If the egg of a fly has 6 chromosomes, how many chromosomes will the body cell have?

7

14

12

10

In many organisms, including flies, eggs are haploid cells, meaning they contain only one set of chromosomes. This set represents half the total number of chromosomes found in body cells, which are typically diploid and contain two sets of chromosomes. Therefore, if the egg of a fly has 6 chromosomes, its body cells, having two sets, will contain double that number. This results in body cells with 12 chromosomes, maintaining genetic stability across generations through sexual reproduction processes.

Explanation

In many organisms, including flies, eggs are haploid cells, meaning they contain only one set of chromosomes. This set represents half the total number of chromosomes found in body cells, which are typically diploid and contain two sets of chromosomes. Therefore, if the egg of a fly has 6 chromosomes, its body cells, having two sets, will contain double that number. This results in body cells with 12 chromosomes, maintaining genetic stability across generations through sexual reproduction processes.

2. What are proteins made of?

Fatty acids

Nucleotides

Amino acids

Sugars

Proteins are made of amino acids. Amino acids are the building blocks of proteins and are linked together through peptide bonds to form long chains. These chains then fold into specific three-dimensional structures, which determine the protein's function. Fatty acids are components of lipids, nucleotides are the building blocks of nucleic acids, and sugars are carbohydrates. Therefore, none of these options are correct when it comes to the composition of proteins.

Explanation

Proteins are made of amino acids. Amino acids are the building blocks of proteins and are linked together through peptide bonds to form long chains. These chains then fold into specific three-dimensional structures, which determine the protein's function. Fatty acids are components of lipids, nucleotides are the building blocks of nucleic acids, and sugars are carbohydrates. Therefore, none of these options are correct when it comes to the composition of proteins.

3. What are nucleic acids made of?

Sugars

Fatty acids

Nucleotides

Amino acids

Nucleic acids are made up of nucleotides. Nucleotides are the building blocks of nucleic acids, such as DNA and RNA. They consist of a sugar molecule, a phosphate group, and a nitrogenous base. Sugars, fatty acids, and amino acids are not the components of nucleic acids. Sugars are carbohydrates, fatty acids are components of lipids, and amino acids are the building blocks of proteins. Therefore, the correct answer is nucleotides.

Explanation

Nucleic acids are made up of nucleotides. Nucleotides are the building blocks of nucleic acids, such as DNA and RNA. They consist of a sugar molecule, a phosphate group, and a nitrogenous base. Sugars, fatty acids, and amino acids are not the components of nucleic acids. Sugars are carbohydrates, fatty acids are components of lipids, and amino acids are the building blocks of proteins. Therefore, the correct answer is nucleotides.

4. What are lipids made of?

Sugars

Fatty acids

Amino acids

Nucleotides

Lipids are organic molecules that are primarily composed of fatty acids. Fatty acids are long chains of carbon atoms with a carboxyl group at one end. They are hydrophobic in nature and are an essential component of lipids, including triglycerides, phospholipids, and cholesterol. Sugars are carbohydrates, amino acids are the building blocks of proteins, and nucleotides are the building blocks of nucleic acids. Therefore, the correct answer is fatty acids.

Explanation

Lipids are organic molecules that are primarily composed of fatty acids. Fatty acids are long chains of carbon atoms with a carboxyl group at one end. They are hydrophobic in nature and are an essential component of lipids, including triglycerides, phospholipids, and cholesterol. Sugars are carbohydrates, amino acids are the building blocks of proteins, and nucleotides are the building blocks of nucleic acids. Therefore, the correct answer is fatty acids.

5. What are carbohydrates made of?

Amino acids

Fatty acids

Nucleotides

Sugars

Carbohydrates are organic compounds composed primarily of carbon, hydrogen, and oxygen, arranged in smaller sugar molecules known as monosaccharides. These sugars can combine to form more complex carbohydrates like disaccharides and polysaccharides. Unlike amino acids, which are the building blocks of proteins, fatty acids, which are components of lipids, or nucleotides, which construct nucleic acids, sugars specifically make up the structure of carbohydrates.

Explanation

Carbohydrates are organic compounds composed primarily of carbon, hydrogen, and oxygen, arranged in smaller sugar molecules known as monosaccharides. These sugars can combine to form more complex carbohydrates like disaccharides and polysaccharides. Unlike amino acids, which are the building blocks of proteins, fatty acids, which are components of lipids, or nucleotides, which construct nucleic acids, sugars specifically make up the structure of carbohydrates.

6. What is one cause of mutations in DNA?

Uracil

Nitrogen

Chocolate

Radiation

Radiation is a well-known cause of mutations in DNA. When DNA is exposed to radiation, whether it's from ultraviolet light from the sun, X-rays, or radioactive materials, the energy from the radiation can break chemical bonds within the DNA molecule. This breakage can lead to changes in the DNA sequence, which are mutations. These mutations can affect how genes function, potentially leading to cell malfunction, diseases, or cancer. Thus, radiation is a significant environmental factor that can alter the genetic material in organisms, influencing their health and evolutionary trajectory.

Explanation

Radiation is a well-known cause of mutations in DNA. When DNA is exposed to radiation, whether it's from ultraviolet light from the sun, X-rays, or radioactive materials, the energy from the radiation can break chemical bonds within the DNA molecule. This breakage can lead to changes in the DNA sequence, which are mutations. These mutations can affect how genes function, potentially leading to cell malfunction, diseases, or cancer. Thus, radiation is a significant environmental factor that can alter the genetic material in organisms, influencing their health and evolutionary trajectory.

7. What is diffusion?

Going from an area of low to high concentration.

Going from an area of high to low concentration.

Going from an adjacent area to a gradient area.

Going from the nucleus to the mitochondria.

Diffusion is a process where particles move from an area of higher concentration to an area of lower concentration. This movement is a result of the natural kinetic energy that particles possess, which causes them to spread out until they are evenly distributed throughout the available space. Diffusion continues until there is no longer a concentration gradient, meaning that the concentrations are equal throughout the system. This process is crucial in biological systems, as it facilitates the passive transport of substances across cell membranes and within cellular fluids.

Explanation

Diffusion is a process where particles move from an area of higher concentration to an area of lower concentration. This movement is a result of the natural kinetic energy that particles possess, which causes them to spread out until they are evenly distributed throughout the available space. Diffusion continues until there is no longer a concentration gradient, meaning that the concentrations are equal throughout the system. This process is crucial in biological systems, as it facilitates the passive transport of substances across cell membranes and within cellular fluids.

8. What does the process of mitosis accomplish?

Helps organisms grow

Produces identical cells

Helps organisms repair damage

All of the above

Mitosis is a fundamental process in multicellular organisms that accomplishes several crucial functions. First, it enables growth by producing new cells that are identical to the original cell, allowing the organism to increase in size while maintaining the same genetic makeup. Second, mitosis produces cells necessary for tissue repair, helping an organism recover from injury by replacing damaged cells with new ones. Lastly, it also contributes to general cellular turnover, replacing old cells with new ones to ensure the proper functioning of tissues and organs. Through these roles, mitosis is vital for the development, maintenance, and health of organisms.

Explanation

Mitosis is a fundamental process in multicellular organisms that accomplishes several crucial functions. First, it enables growth by producing new cells that are identical to the original cell, allowing the organism to increase in size while maintaining the same genetic makeup. Second, mitosis produces cells necessary for tissue repair, helping an organism recover from injury by replacing damaged cells with new ones. Lastly, it also contributes to general cellular turnover, replacing old cells with new ones to ensure the proper functioning of tissues and organs. Through these roles, mitosis is vital for the development, maintenance, and health of organisms.

9. What do both carbohydrates and lipids provide for the organism?

Provide energy for the organism

Dissolve in water

Taste sweet

Get broken down into sugars

Both carbohydrates and lipids serve as crucial sources of energy for organisms. Carbohydrates are typically the body's primary source of immediate energy. They break down into glucose, which cells use to fuel daily activities and metabolic processes. On the other hand, lipids, which include fats and oils, are more energy-dense and provide a longer-lasting energy reserve. They also play roles in insulation, protecting organs, and forming cell membranes. These nutrients are essential for sustaining bodily functions, supporting growth, and maintaining healthy organ systems, making them vital components of a balanced diet.

Explanation

Both carbohydrates and lipids serve as crucial sources of energy for organisms. Carbohydrates are typically the body's primary source of immediate energy. They break down into glucose, which cells use to fuel daily activities and metabolic processes. On the other hand, lipids, which include fats and oils, are more energy-dense and provide a longer-lasting energy reserve. They also play roles in insulation, protecting organs, and forming cell membranes. These nutrients are essential for sustaining bodily functions, supporting growth, and maintaining healthy organ systems, making them vital components of a balanced diet.

10. What are the products of photosynthesis?

Carbon dioxide and water

Oxygen and glucose

Water, carbon dioxide, and ATP

ATP and water

During photosynthesis, plants use carbon dioxide and water to produce glucose and oxygen. This process occurs in the chloroplasts of plant cells, specifically in the presence of sunlight. The chlorophyll in the chloroplasts captures sunlight energy, which is then used to convert carbon dioxide and water into glucose. Oxygen is released as a byproduct of this reaction. Glucose is an essential energy source for plants, while oxygen is released into the atmosphere and is vital for the survival of other organisms. Therefore, the correct answer is "Oxygen and glucose."

Explanation

During photosynthesis, plants use carbon dioxide and water to produce glucose and oxygen. This process occurs in the chloroplasts of plant cells, specifically in the presence of sunlight. The chlorophyll in the chloroplasts captures sunlight energy, which is then used to convert carbon dioxide and water into glucose. Oxygen is released as a byproduct of this reaction. Glucose is an essential energy source for plants, while oxygen is released into the atmosphere and is vital for the survival of other organisms. Therefore, the correct answer is "Oxygen and glucose."

11. What are enzymes characterized by?

Are usually proteins

Increase the rate of chemical reactions

Reduce activation energy of chemical reactions

All of the above

Enzymes are typically proteins that play a crucial role in facilitating and accelerating biochemical reactions within organisms, which is known as catalysis. They do this primarily by lowering the activation energy required for reactions to occur, making the process much faster and more efficient than it would be without their presence. By reducing activation energy, enzymes enable our bodies to perform complex chemical transformations quickly and under mild conditions, supporting everything from digestion to DNA replication. This fundamental attribute allows life's processes to occur at the speeds necessary for survival and function.

Explanation

Enzymes are typically proteins that play a crucial role in facilitating and accelerating biochemical reactions within organisms, which is known as catalysis. They do this primarily by lowering the activation energy required for reactions to occur, making the process much faster and more efficient than it would be without their presence. By reducing activation energy, enzymes enable our bodies to perform complex chemical transformations quickly and under mild conditions, supporting everything from digestion to DNA replication. This fundamental attribute allows life's processes to occur at the speeds necessary for survival and function.

12. What does the process of cellular respiration involve? (Select all that apply)

All organisms

Converts chemical energy in food to usable energy (ATP) in all organisms

Only in animals

Perform only by the ones who can't do photosynthesis

Cellular respiration is a fundamental biological process where chemical energy found in food is converted into adenosine triphosphate (ATP), a form of energy that all organisms can use. This process is not exclusive to any specific group; rather, it occurs in all organisms, including plants, animals, and microbes. Cellular respiration is essential for life because it provides the energy necessary for various biological functions such as growth, reproduction, and maintaining homeostasis. By converting energy stored in chemical bonds into a usable form, organisms can perform their daily activities efficiently.

Explanation

Cellular respiration is a fundamental biological process where chemical energy found in food is converted into adenosine triphosphate (ATP), a form of energy that all organisms can use. This process is not exclusive to any specific group; rather, it occurs in all organisms, including plants, animals, and microbes. Cellular respiration is essential for life because it provides the energy necessary for various biological functions such as growth, reproduction, and maintaining homeostasis. By converting energy stored in chemical bonds into a usable form, organisms can perform their daily activities efficiently.

13. Where do most of the cell's chemical reactions take place?

Nucleus

Vacuole

Cytoplasm

Centriole

The cytoplasm is the fluid-filled region of a cell that contains various organelles and is the site where most of the cell's chemical reactions occur. It provides a medium for the transport and interaction of molecules, enzymes, and other cellular components necessary for metabolic processes. The nucleus is the control center of the cell and contains the cell's genetic material, but it is not where most chemical reactions occur. Vacuoles are storage structures in plant cells and do not play a significant role in chemical reactions. Centrioles are involved in cell division and do not directly participate in chemical reactions.

Explanation

The cytoplasm is the fluid-filled region of a cell that contains various organelles and is the site where most of the cell's chemical reactions occur. It provides a medium for the transport and interaction of molecules, enzymes, and other cellular components necessary for metabolic processes. The nucleus is the control center of the cell and contains the cell's genetic material, but it is not where most chemical reactions occur. Vacuoles are storage structures in plant cells and do not play a significant role in chemical reactions. Centrioles are involved in cell division and do not directly participate in chemical reactions.

14. What does a prokaryotic cell not have?

Cell membrane

Cytoplasm

Nuclear membrane

Ribosomes

A prokaryotic cell does not have a nuclear membrane because prokaryotes do not have a true nucleus. Unlike eukaryotic cells, prokaryotic cells lack a distinct membrane-bound nucleus to contain their genetic material. Instead, their DNA is typically found in a region called the nucleoid, which is not enclosed by a nuclear membrane. Prokaryotic cells still have a cell membrane, cytoplasm, and ribosomes, which are essential components for their structure and function.

Explanation

A prokaryotic cell does not have a nuclear membrane because prokaryotes do not have a true nucleus. Unlike eukaryotic cells, prokaryotic cells lack a distinct membrane-bound nucleus to contain their genetic material. Instead, their DNA is typically found in a region called the nucleoid, which is not enclosed by a nuclear membrane. Prokaryotic cells still have a cell membrane, cytoplasm, and ribosomes, which are essential components for their structure and function.

15. Which of the following is NOT a characteristic of prokaryotic cells?

Lack of a nucleus

Presence of membrane-bound organelles

1 Smaller size compared to eukaryotic cells

Circular DNA

Prokaryotic cells, such as bacteria and archaea, are characterized by their simple structure and lack of a true nucleus. Their DNA is not enclosed within a membrane-bound nucleus but exists as a single circular chromosome in the cytoplasm. They also lack other membrane-bound organelles, such as mitochondria and chloroplasts, which are found in eukaryotic cells.

Explanation

Prokaryotic cells, such as bacteria and archaea, are characterized by their simple structure and lack of a true nucleus. Their DNA is not enclosed within a membrane-bound nucleus but exists as a single circular chromosome in the cytoplasm. They also lack other membrane-bound organelles, such as mitochondria and chloroplasts, which are found in eukaryotic cells.

16. What can change the shape and function of an enzyme?

Enzyme concentration and temperature

PH and enzyme concentration

PH and Temperature

Only enzyme concentration

The shape of an enzyme and its function can be changed by pH and temperature. Enzymes are proteins that have a specific three-dimensional shape, which is crucial for their function. pH refers to the acidity or alkalinity of the environment, and extreme pH levels can denature or alter the shape of the enzyme, rendering it ineffective. Similarly, temperature influences the kinetic energy of molecules, including enzymes. High temperatures can cause enzymes to denature, while low temperatures can slow down their activity. Therefore, both pH and temperature play a significant role in modifying the shape and function of enzymes.

Explanation

The shape of an enzyme and its function can be changed by pH and temperature. Enzymes are proteins that have a specific three-dimensional shape, which is crucial for their function. pH refers to the acidity or alkalinity of the environment, and extreme pH levels can denature or alter the shape of the enzyme, rendering it ineffective. Similarly, temperature influences the kinetic energy of molecules, including enzymes. High temperatures can cause enzymes to denature, while low temperatures can slow down their activity. Therefore, both pH and temperature play a significant role in modifying the shape and function of enzymes.

17. What is not true about energy transformation in living things?

Plants absorb energy from the sunlight during photosynthesis and convert it into heat energy.

Light energy is converted to chemical energy by plants during photosynthesis.

Chemical energy is transformed into heat energy as organisms carry out respiration.

Energy is stored by plants in bonds of organic compounds used as a food.

The statement that plants convert sunlight into heat energy during photosynthesis is incorrect. In photosynthesis, plants absorb light energy from the sun and convert it into chemical energy, which is stored in the bonds of glucose and other organic compounds. This chemical energy is then used by the plant for growth and metabolism or stored for later use. Heat is a byproduct of many metabolic processes, but it is not the primary product of photosynthesis, where the focus is on creating usable chemical energy rather than heat.

Explanation

The statement that plants convert sunlight into heat energy during photosynthesis is incorrect. In photosynthesis, plants absorb light energy from the sun and convert it into chemical energy, which is stored in the bonds of glucose and other organic compounds. This chemical energy is then used by the plant for growth and metabolism or stored for later use. Heat is a byproduct of many metabolic processes, but it is not the primary product of photosynthesis, where the focus is on creating usable chemical energy rather than heat.

18. How do enzymes speed up chemical reactions?

Decreasing amount of energy needed to start a reaction

Increasing the amount of energy needed to start a reaction

Adding heat to the reaction

Removing heat from the reaction

Enzymes accelerate chemical reactions by decreasing the amount of activation energy needed to start those reactions. Activation energy is the energy barrier that must be overcome for a reaction to occur. By binding to substrate molecules, enzymes create an environment where chemical bonds can be formed or broken more easily, effectively lowering this barrier. This process allows reactions to proceed rapidly and at lower temperatures than would otherwise be required. Thus, enzymes are vital for sustaining life's biochemical processes efficiently.

Explanation

Enzymes accelerate chemical reactions by decreasing the amount of activation energy needed to start those reactions. Activation energy is the energy barrier that must be overcome for a reaction to occur. By binding to substrate molecules, enzymes create an environment where chemical bonds can be formed or broken more easily, effectively lowering this barrier. This process allows reactions to proceed rapidly and at lower temperatures than would otherwise be required. Thus, enzymes are vital for sustaining life's biochemical processes efficiently.

19. What do nucleic acids control in addition to cell activity?

Transfer energy and prevent body heat loss

Determine Heredity and transfer energy

Transfer energy and store energy

Prevent body heat loss and determine heredity

Nucleic acids, specifically DNA and RNA, are crucial for more than just controlling cellular activities. They play a pivotal role in determining heredity by transmitting genetic information from one generation to the next. This genetic information is responsible for defining traits and characteristics that are inherited. Additionally, nucleic acids are involved in the transfer of energy within cells, particularly through the process of creating and utilizing molecules like ATP (Adenosine Triphosphate), which are essential for powering various cellular functions. This dual role ensures that organisms not only maintain proper cellular function but also preserve and pass on genetic traits.

Explanation

Nucleic acids, specifically DNA and RNA, are crucial for more than just controlling cellular activities. They play a pivotal role in determining heredity by transmitting genetic information from one generation to the next. This genetic information is responsible for defining traits and characteristics that are inherited. Additionally, nucleic acids are involved in the transfer of energy within cells, particularly through the process of creating and utilizing molecules like ATP (Adenosine Triphosphate), which are essential for powering various cellular functions. This dual role ensures that organisms not only maintain proper cellular function but also preserve and pass on genetic traits.

20. What is being cycled between cellular respiration and photosynthesis?

Energy

Matter

Both matter and energy

None of the above

Both matter and energy are cycled between cellular respiration and photosynthesis. In photosynthesis, plants convert light energy into chemical energy stored in glucose, using carbon dioxide and water (matter). In cellular respiration, organisms break down glucose to release energy, producing carbon dioxide and water as byproducts. This cycle ensures the continuous flow of matter (carbon, oxygen, hydrogen) and energy within ecosystems, sustaining life on Earth.

Explanation

Both matter and energy are cycled between cellular respiration and photosynthesis. In photosynthesis, plants convert light energy into chemical energy stored in glucose, using carbon dioxide and water (matter). In cellular respiration, organisms break down glucose to release energy, producing carbon dioxide and water as byproducts. This cycle ensures the continuous flow of matter (carbon, oxygen, hydrogen) and energy within ecosystems, sustaining life on Earth.