Cells Unit Pre-assessment (Grade 7)

The given question asks the respondent to rate their interest in cells and cell processes on a scale of 1 to 4. The answer options provided are 1, 2, 3, and 4, which correspond to the different levels of interest. The respondent can choose the number that best represents their level of interest, with 1 being the lowest and 4 being the highest.

The answer is 1,2,3,4 because the question asks the respondent to rate their knowledge about cells and cell processes on a scale of 1 to 4. The options provided are 1, 2, 3, and 4, indicating the different levels of knowledge. The respondent can choose any of these options based on their own understanding and familiarity with the topic.

The cell membrane is responsible for controlling the movement of molecules in and out of the cell. It acts as a barrier, allowing only certain molecules to pass through while blocking others. Additionally, the cell membrane contains receptors that can recognize and respond to chemical signals, allowing the cell to communicate with its environment. The cell wall provides structural support but does not regulate molecule movement or chemical recognition. The nucleus contains the cell's genetic material but is not directly involved in these functions. The mitochondria and chloroplasts are involved in energy production and are not primarily responsible for controlling molecule movement or chemical recognition.

The correct answer is "Releasing the stored energy of organic compounds by the process of respiration". This is because respiration is the process by which cells break down organic compounds, such as glucose, to release energy in the form of ATP molecules. ATP is the main energy currency of cells and is used for various cellular processes. Recycling light energy for photosynthesis, breaking down starch through digestion, and copying coded information during protein synthesis are not directly related to the production of ATP molecules.

The correct answer describes the function of a cell as breaking down large organic food molecules like protein and using the building blocks to synthesize organic compounds necessary for life. This process is essential for the cell to obtain energy and create necessary molecules for its survival. The other options either incorrectly state that large organic food molecules directly enter the cell for energy or that the cell does not require nutrients from the outside environment.

The diagram represents some events in a plant cell, which suggests that the events are related to photosynthesis. During photosynthesis, plants use carbon dioxide, light, and water to produce glucose and oxygen. Therefore, the letters X, Y, and Z most likely represent carbon dioxide, light, and water.

The correct answer is chloroplasts, a cell wall, and a large vacuole. Chloroplasts are responsible for photosynthesis and are found only in plant cells. A cell wall provides structural support and protection to plant cells, while animal cells do not have a cell wall. A large vacuole is present in plant cells to store water, nutrients, and waste products, whereas animal cells have smaller vacuoles or none at all.

The correct order of organization from least complex to most complex is as follows: organelles, cells, tissues, organs, organ systems, organisms. Organelles are the smallest functional units within a cell, followed by cells, which are the basic building blocks of living organisms. Tissues are groups of cells that work together to perform a specific function, while organs are composed of different tissues and perform specific functions in the body. Organ systems are groups of organs that work together to carry out a particular function, and organisms are complete living entities made up of multiple organ systems.

The mitochondrion is the organelle most directly involved in cellular aerobic respiration. It is often referred to as the "powerhouse" of the cell because it is responsible for producing ATP, the main source of energy for cellular processes. Within the mitochondria, aerobic respiration takes place in the form of the Krebs cycle and the electron transport chain. These processes involve the breakdown of glucose and the production of carbon dioxide, water, and ATP. Therefore, the mitochondrion plays a crucial role in generating energy for the cell through aerobic respiration.

Neurotransmitters are substances that are secreted at the endings of nerve cells. These chemicals are responsible for transmitting signals between nerve cells, allowing for communication within the nervous system. Antibodies are part of the immune system and are not secreted by nerve cells. Antigens are substances that trigger an immune response. Lipids are a type of fat molecule and are not specifically secreted by nerve cells. Neurons are the cells that make up the nervous system and can secrete neurotransmitters.

The correct answer is "Ingestion". In the diagram, the ameba is shown engulfing a food particle, which is a process known as ingestion. Ingestion is the act of taking in food or nutrients into the body, and it is a characteristic activity of living organisms, including single-celled protists like amebas.

Catalase is an enzyme that functions in the breakdown of hydrogen peroxide. Enzymes are biological catalysts that speed up chemical reactions in living organisms. In this case, catalase catalyzes the decomposition of hydrogen peroxide into water and oxygen. This reaction is important because hydrogen peroxide is toxic and can damage cells if it accumulates. Therefore, catalase plays a crucial role in maintaining cellular health by breaking down hydrogen peroxide into harmless substances.

Osmosis is the correct answer because it involves the movement of water molecules from an area of higher concentration (lower solute concentration) to an area of lower concentration (higher solute concentration) through a semi-permeable membrane. This process occurs spontaneously and does not require any energy input. Diffusion refers to the movement of particles, not specifically water, from an area of higher concentration to an area of lower concentration. Active transport, hydrolysis, and phagocytosis involve the movement of substances across a membrane with the use of energy.

The body cells of most multicellular animals are not in direct contact with the external environment, so they rely on a circulatory system to supply them with materials from the environment. A circulatory system, such as the cardiovascular system in humans, transports oxygen, nutrients, hormones, and other necessary substances to the cells through the bloodstream. This system also helps remove waste products and carbon dioxide from the cells. Therefore, a circulatory system is essential for the survival and proper functioning of the body cells in multicellular animals.