AQA GCSE Biology Module 2 Revision Quiz

Mitochondria are the correct answer because they are the organelles responsible for carrying out respiration reactions in animal cells. Respiration is the process by which cells convert glucose and oxygen into energy in the form of ATP. Mitochondria have a double membrane and contain their own DNA, allowing them to produce the enzymes necessary for respiration. They are often referred to as the "powerhouses" of the cell because they generate the majority of the cell's energy.

Chloroplasts are responsible for carrying out photosynthesis in plant cells. Photosynthesis is the process by which plants convert light energy into chemical energy in the form of glucose. Chlorophyll, a pigment found in chloroplasts, absorbs light energy from the sun. This absorbed energy is then used to convert carbon dioxide and water into glucose and oxygen. Therefore, the best description of the role of chloroplasts in photosynthesis is that they contain chlorophyll to absorb light energy.

Chloroplasts are the correct answer because they are the organelles responsible for photosynthesis in plant cells. During photosynthesis, light energy is converted into chemical energy in the form of glucose. Chloroplasts contain chlorophyll, a pigment that captures light energy, and other molecules necessary for the chemical reactions of photosynthesis to occur. The other options, such as the nucleus, ribosomes, and mitochondria, are not involved in the process of converting light energy into chemical energy.

The active site is the correct answer because it refers to the specific region on an enzyme where the substrate molecule binds and undergoes a chemical reaction. This site has a complementary shape to the substrate and contains specific amino acid residues that facilitate the catalytic activity of the enzyme. The active site plays a crucial role in enzyme-substrate interactions and is essential for the enzyme's function.

Animal cells do not have a cell wall, which is a rigid structure found in plant cells and some other organisms. Instead, animal cells have a flexible cell membrane that surrounds the cell and regulates the movement of substances in and out of the cell. Additionally, animal cells typically have smaller vacuoles compared to plant cells, and they are not as prominent or central to the cell's function. Therefore, both the cell wall and large vacuole are not found in animal cells.

Ribosomes are the correct answer because they are responsible for protein synthesis in cells. Ribosomes are small, spherical structures found in the cytoplasm of cells. They are composed of RNA and proteins and function as the site where amino acids are assembled into proteins according to the instructions provided by the genetic material. Ribosomes can be found either floating freely in the cytoplasm or attached to the endoplasmic reticulum. They play a crucial role in the synthesis of proteins, which are essential for various cellular processes and functions.

Plants require nitrates for proper growth and development. Without nitrates, plants are unable to synthesize amino acids and proteins, which are essential for their growth. As a result, plants grown without nitrates will be smaller than normal because they lack the necessary nutrients to support their full growth potential.

Short food chains are more energy efficient compared to long food chains because they involve fewer steps and transfers of energy. In a short food chain, energy from the sun is directly transferred to producers (plants), which are then consumed by primary consumers (herbivores), and so on. With each step, some energy is lost as heat, so shorter chains result in less energy loss. In contrast, long food chains involve additional steps and transfers of energy, leading to more energy loss and reduced efficiency. Therefore, short food chains are more energy efficient.

The biomass of an organism refers to the total mass of living material in that organism. This includes all the organic matter such as cells, tissues, and organs. Therefore, the best representation of an organism's biomass would be the mass of its living material. This measurement provides an accurate reflection of the amount of biological material present in the organism.

The carbon cycle involves the movement of carbon between the atmosphere, living organisms, and the Earth's surface. Respiration and photosynthesis are two key processes in the carbon cycle. Respiration releases carbon dioxide into the atmosphere, while photosynthesis absorbs carbon dioxide from the atmosphere. Diffusion of carbon dioxide is another process that plays a role in the carbon cycle by allowing the gas to move between different parts of the environment. However, absorption of nitrate ions is not directly involved in the carbon cycle. Nitrate ions are more closely associated with the nitrogen cycle, which involves the movement of nitrogen in various forms through the environment.

The best description about the structure of a metabolically active cell is that it contains many mitochondria. Mitochondria are the powerhouses of the cell and are responsible for generating energy through cellular respiration. In metabolically active cells, such as muscle cells, there is a high demand for energy, thus requiring a large number of mitochondria to meet this demand.

In an investigation measuring the effect of increasing light intensity on the rate of photosynthesis in an aquatic plant, the independent variable is the distance between the light source and the plant. This is because the distance between the light source and the plant is being manipulated or controlled by the researcher in order to observe its effect on the rate of photosynthesis. The other options mentioned, such as bubbles of oxygen produced per minute, temperature of the water, and concentration of dissolved carbon dioxide, are not being directly manipulated in this investigation.

Oxygen and carbon dioxide enter or leave cells by diffusion because they are small, nonpolar molecules that can easily pass through the cell membrane. Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration, and since oxygen and carbon dioxide are small and nonpolar, they can diffuse across the lipid bilayer of the cell membrane. Water, although small, enters or leaves cells through osmosis, not diffusion. Starch, on the other hand, is a large, polar molecule that cannot pass through the cell membrane by diffusion.

The correct answer is the guard cells. Guard cells are specialized cells found in the epidermis of leaves. They control the opening and closing of stomata, which are small openings on the leaf surface that allow for gas exchange and transpiration. When the guard cells are turgid, they open the stomata, allowing for gas exchange but also increasing the potential for water loss through transpiration. However, when the guard cells are flaccid, they close the stomata, reducing water loss and preventing excessive transpiration. Therefore, the guard cells play a crucial role in regulating water loss and preventing dehydration in the leaf.

The dependent variable in this investigation is the bubbles of oxygen produced per minute. The purpose of the investigation is to measure the effect of increasing light intensity on the rate of photosynthesis. The number of bubbles of oxygen produced per minute is directly influenced by the rate of photosynthesis, which in turn is affected by the light intensity. Therefore, the number of bubbles of oxygen produced per minute is the dependent variable that is being measured and observed in this investigation.

A line graph with distance between light source and plant on the x axis is the best description for the type of chart used to summarize the findings because it allows for the visualization of the relationship between the independent variable (distance between light source and plant) and the dependent variable (rate of photosynthesis). The x-axis represents the distance between the light source and the plant, while the y-axis represents the rate of photosynthesis. By plotting the data points on a line graph, it becomes easier to observe any patterns or trends in how the rate of photosynthesis changes with increasing light intensity.

Saprophytes are organisms that obtain nutrients by decomposing dead organic matter. They play a crucial role in the process of decay. Succulents are plants that store water in their leaves, stems, or roots, and they are not directly involved in the decay process. Simbionts is not a recognized term, and snakes are not typically associated with causing decay. Therefore, the correct answer is saprophytes.

Enzymes are biological catalysts that speed up chemical reactions in living organisms. They achieve this by lowering the activation energy required for the reaction to occur. Enzymes are highly specific and can only catalyze a particular reaction or a group of similar reactions. They are not consumed or changed during the reaction, allowing them to be used repeatedly. Enzymes work optimally at moderate temperatures, as extreme temperatures can denature them and render them inactive. Therefore, the correct answer is that enzymes increase the rate of reaction at moderate temperatures.

In photosynthesis, plants use water and carbon dioxide to produce glucose and oxygen. Water is absorbed by the roots and transported to the leaves, where it is combined with carbon dioxide from the air. Through the process of photosynthesis, light energy from the sun is converted into chemical energy in the form of glucose, while oxygen is released as a byproduct. Therefore, the best description of substances used in photosynthesis is water and carbon dioxide.

The statement "They all contain chromosomes in pairs" is not a characteristic of all nuclei because not all nuclei have chromosomes in pairs. Some organisms, such as bacteria, have a single circular chromosome, while others, like fungi, have multiple linear chromosomes. Therefore, the presence of chromosomes in pairs is not a universal characteristic of all nuclei.

The human egg cell is larger compared to a human sperm cell because it contains nourishment for the zygote and embryo. This is essential for the early development of the fertilized egg. The egg cell provides the necessary nutrients and resources for the growing zygote, allowing it to develop into an embryo. In contrast, sperm cells are smaller and more streamlined, as their main function is to reach and fertilize the egg cell. The larger size of the egg cell allows it to support the early stages of development until the embryo can establish its own nutrient supply.

The palisade layer is the correct answer because it is the main site of photosynthesis in the leaf. This layer is located just below the upper epidermis and contains elongated cells that are packed with chloroplasts. These chloroplasts contain the pigment chlorophyll, which is responsible for capturing light energy and converting it into chemical energy through photosynthesis. The palisade layer is specifically adapted for efficient light absorption, making it the primary site for photosynthesis in the leaf.

Carbon dioxide availability would not cause a high rate of decomposition. Decomposition is primarily driven by the activity of decomposer organisms, such as bacteria and fungi, which require oxygen to carry out their metabolic processes. Oxygen availability, warmth, and moisture are all essential factors that promote the growth and activity of decomposers, leading to increased decomposition rates. However, carbon dioxide availability does not directly affect the rate of decomposition as it is a byproduct of the decomposition process rather than a limiting factor.

Glucose is not moved between plant cells by osmosis. Osmosis is the movement of water molecules across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. Glucose, being a solute, does not move by osmosis. Instead, glucose is transported within plants through active transport or facilitated diffusion.

The distance between the light source and the plant is a continuous variable because it can take on any value within a certain range. In this investigation, the distance can be measured in millimeters, centimeters, or any other unit of length, and it can vary continuously from a minimum value to a maximum value. This variable is important to measure because it directly affects the amount of light reaching the plant, which in turn affects the rate of photosynthesis.

An increase in carbon dioxide would not cause a change in the rate of photosynthesis if light intensity is the limiting factor because the limiting factor in this scenario is light, not carbon dioxide. Even if there is an increase in carbon dioxide, the rate of photosynthesis cannot increase if there is not enough light available for the process. Therefore, the rate of photosynthesis will remain unchanged.

The statement that the heater produced light for the greenhouse is not a good explanation for the effect of the heater because light is not mentioned as a factor that would improve the yield of plants. The other options, such as increasing temperature, increasing carbon dioxide, and extending the growing season, are all factors that can positively impact plant growth and yield.

The cells lining the gut of a human do not contain a thin cell wall. Unlike plant cells, animal cells do not have a cell wall. Instead, they have a cell membrane which acts as a protective barrier and regulates the movement of substances in and out of the cell. The cells lining the gut also have microvilli, which increase the surface area for absorption, and many mitochondria, which provide energy for cellular processes.

Osmosis is the process by which water molecules move from an area of lower solute concentration to an area of higher solute concentration through a semipermeable membrane. In this case, the correct answer states that osmosis involves the movement of water into a more concentrated solution, which aligns with the definition of osmosis.

The cell wall of a plant cell provides structural support and helps resist the outward pressure of a water-filled cell. It acts as a rigid barrier that prevents the cell from bursting due to the osmotic pressure created by the high concentration of water inside the cell. This is especially important in plant cells, as they have a large central vacuole that stores water. The cell wall also allows for the passage of water and other substances through specialized channels called plasmodesmata.

The energy in food chains is ultimately traced back to light energy. This is because producers, such as plants, use photosynthesis to convert light energy into chemical energy in the form of glucose. This glucose is then used by the producers themselves for their own energy needs and is also passed on to the primary consumers (herbivores) when they consume the producers. The energy from the primary consumers is then transferred to the secondary consumers and so on, creating a flow of energy through the food chain. Therefore, light energy is the initial source of energy in the food chain.

The correct answer is nucleus, ribosome, cell membrane width. This is because the nucleus is the largest of the three cell structures listed, followed by the ribosome, and then the cell membrane width. The nucleus is the control center of the cell and contains the cell's DNA. Ribosomes are responsible for protein synthesis. The cell membrane width, also known as the plasma membrane, is the outer boundary of the cell and regulates the movement of substances in and out of the cell.

Starch is a better compound than glucose for storing energy in cells because it is a large compound that is not readily lost from cells. Unlike glucose, which can easily diffuse out of the cell, starch molecules are too large to pass through the cell membrane. This allows cells to store starch for longer periods of time, ensuring a more stable and sustained energy supply.

The spongy layer is the correct answer because it is the region of the leaf that contains air spaces between the cells. These air spaces allow for the exchange of gases, such as oxygen and carbon dioxide, between the leaf and the environment. The upper epidermis and palisade layer are important for photosynthesis, but they do not play a direct role in gas exchange. The guard cells are responsible for regulating the opening and closing of the stomata, which are pores on the leaf surface that also contribute to gas exchange, but they are not the primary site of gas exchange.

Magnesium is a mineral ion that plays a crucial role in chlorophyll synthesis. Chlorophyll is responsible for the green color in plants and is essential for photosynthesis. A deficiency in magnesium can lead to a decrease in chlorophyll production, resulting in yellowing leaves. Therefore, a deficiency in magnesium causes plants to have yellow leaves.

The energy in grass is not transferred into the muscles of cows in three ways. Firstly, energy is used by the cow in movement, meaning that some of the energy is expended in activities such as walking or running. Secondly, energy is used by the cow to replace lost body heat, as cows generate heat through their metabolic processes and need to maintain their body temperature. Lastly, energy is used to join amino acids together to make muscle protein, which is a crucial process for muscle growth and repair.

The percentage of energy available to the next organism in the food chain is 0.1%. This is because the plant fixes 1000Kj of energy from every 1000,000Kj of energy reaching it from the sun. To find the percentage, we divide the energy fixed by the plant (1000Kj) by the total energy reaching the plant (1000,000Kj) and multiply by 100. This gives us 0.1%, which represents the proportion of energy that is available to the next organism in the food chain.

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The bubbles produced per minute in this investigation can be considered as a continuous variable. This is because the number of bubbles produced can take on any value within a certain range, and it can be measured and recorded as a decimal or fraction. It is not limited to specific whole numbers or categories, making it a continuous variable.

If an animal cell is suspended in a very weak salt solution, the cell will burst. This is because the salt solution is hypotonic compared to the cell's cytoplasm. As a result, water will enter the cell through osmosis, causing it to swell and eventually burst.

When the chicken contracts its muscles, it requires energy to do so. However, this energy is wasted as it does not contribute to the overall energy transfer between the chicken and the fox. On the other hand, when the fox excretes some of the chicken it has consumed, it is also wasting energy as this energy is not being transferred to the fox's body for its own use. Therefore, both the chicken contracting muscles and the fox excreting some of the chicken are sources of wasted energy in this scenario.