Life Science - Semester 1 Final

Living things are made of cells. Cells are the basic structural and functional units of life. They are responsible for carrying out all the necessary processes to maintain life. Cells can be found in all living organisms, from simple single-celled organisms like bacteria to complex multicellular organisms like plants and animals. Cells are composed of various components such as cell membranes, cytoplasm, and genetic material. Therefore, the answer "cells" is correct as it accurately describes the fundamental building blocks of all living things.

The chemical symbol for glucose is C6H12O6. This is because glucose is a carbohydrate with the molecular formula C6H12O6, indicating that it is composed of 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. The other options given, O2, CO2, and H2O, are not the chemical symbols for glucose. O2 represents molecular oxygen, CO2 represents carbon dioxide, and H2O represents water.

Most living organisms are made up of molecules that contain primarily oxygen, carbon, hydrogen, and nitrogen. Nitrogen is an essential element for life as it is a key component of proteins, nucleic acids, and other important biological molecules. It plays a crucial role in the structure and function of living organisms, including DNA replication, protein synthesis, and metabolism. Therefore, nitrogen is the correct answer to the question.

Water is the molecule needed for life that does not contain carbon. It is an essential component for various biological processes and is involved in many biochemical reactions. Water is crucial for maintaining cell structure and function, regulating body temperature, transporting nutrients and waste, and facilitating chemical reactions. Although carbon is a fundamental element for life, water is an exception as it consists of two hydrogen atoms bonded to one oxygen atom, without any carbon atoms present.

Mass is a measure of the amount of matter in an object. It is commonly measured in grams, which is a unit of mass in the metric system. Grams are used because they provide a convenient and easily understandable scale for measuring the mass of various objects. Milliliters and centimeters are units of volume and length, respectively, and are not appropriate for measuring mass. Ounces, on the other hand, are a unit of mass commonly used in the imperial system, but grams are the preferred unit of measurement in most scientific and everyday contexts.

Both plant and animal cells contain DNA. DNA is the genetic material that carries the instructions for the development, functioning, and reproduction of all living organisms. It is present in the nucleus of both plant and animal cells, and it plays a crucial role in determining the characteristics and traits of an organism. DNA contains the information necessary for the synthesis of proteins, which are essential for the structure and function of cells. Therefore, the statement that both plant and animal cells contain DNA is true.

Photosynthesis is the process by which plants convert sunlight, water, and carbon dioxide into glucose and oxygen. Glucose is a high-energy molecule that serves as the primary source of energy for plants and is also used to produce other important molecules like starch and cellulose. Therefore, the correct answer is glucose.

The nucleus contains DNA. DNA is the genetic material of an organism and is responsible for carrying the genetic information that determines the traits and characteristics of an individual. The nucleus is a membrane-bound organelle found in eukaryotic cells and is the site where DNA is stored and replicated. It is often referred to as the "control center" of the cell because it regulates gene expression and controls cellular activities. Therefore, the correct answer is the nucleus.

The correct answer is 3.2 cm because it is the only option that is rounded to the nearest tenth of a centimeter. The other options are either rounded to the nearest whole centimeter or rounded to a different decimal place.

Plant leaves undergo a process called photosynthesis, in which they use sunlight, water, and carbon dioxide to produce glucose and oxygen. Oxygen is released as a byproduct during this process and is the most likely gas given off by plant leaves.

Autotrophs are organisms that can produce their own food using sunlight through the process of photosynthesis. They convert solar energy into chemical energy, which they use to fuel their metabolic activities. This ability to harness sunlight as an energy source sets autotrophs apart from consumers and heterotrophs, which obtain energy by consuming other organisms or organic matter. Unicellular refers to organisms that consist of a single cell, but it does not specifically relate to their energy source. Therefore, the correct answer is autotrophs.

The respiratory system exchanges carbon dioxide and oxygen. When we breathe in, oxygen from the air enters our lungs and is transported to our body's cells through the bloodstream. At the same time, carbon dioxide, a waste product generated by our cells, is carried back to the lungs and exhaled. This exchange of gases allows our body to obtain the oxygen it needs for energy production and get rid of the carbon dioxide waste.

Fats, oils, and waxes are examples of lipids. Lipids are a group of molecules that are insoluble in water but soluble in organic solvents. They are composed of carbon, hydrogen, and oxygen atoms and are an important source of energy for the body. Fats, oils, and waxes are all types of lipids that serve various functions in organisms, such as energy storage, insulation, and protection.

A heterotroph gets its energy by eating other organisms. Heterotrophs are unable to produce their own food through photosynthesis, so they rely on consuming other organisms to obtain energy. This process is known as heterotrophic nutrition. By consuming other organisms, heterotrophs break down the organic molecules present in their food and use them as a source of energy for their own metabolic processes.

Metabolism is the correct answer because it refers to the chemical reactions that occur within an organism to break down food and convert it into energy. This process is essential for the organism to function properly and carry out its various biological processes. Evolution, homeostasis, and osmosis are not directly related to the breakdown of food for energy.

Tissues combine to form organs. Organs are composed of different types of tissues that work together to perform specific functions in the body. Organs, in turn, combine to form organ systems, which work together to carry out complex functions necessary for the survival of organisms. Therefore, the correct answer is organs.

Animals do not have a cell wall. A cell wall is a rigid structure that surrounds the cell membrane in plants, fungi, and bacteria, providing support and protection. In animals, the cell membrane is the outermost layer that separates the cell from its environment and regulates the movement of substances in and out of the cell. Animals do have a cell membrane, mitochondria (which are responsible for energy production), and a nucleus (which contains the cell's genetic material).

Homeostasis is the correct answer because it refers to the process by which organisms maintain a stable internal environment despite changes in the external conditions. It involves various physiological mechanisms that regulate body temperature, pH levels, blood pressure, and other vital parameters within a narrow range. Through homeostasis, organisms can adapt to different environmental conditions and ensure the proper functioning of cells and organs. Metabolism, stimulus, and osmosis are not accurate choices as they do not specifically pertain to the maintenance of internal conditions.

Bacteria are considered prokaryotic cells because they lack a nucleus and membrane-bound organelles. Prokaryotic cells are typically smaller and simpler in structure compared to eukaryotic cells, which have a true nucleus and membrane-bound organelles. Bacteria are single-celled organisms that can be found in various environments and play important roles in ecosystems.

The organization levels of the digestive system start with cells, which are the basic building blocks of the system. These cells then come together to form tissues, which are groups of cells that work together to perform specific functions. The tissues then combine to form organs, which are structures made up of different types of tissues that work together to carry out specific functions. Finally, the organs work together as part of the organ systems, such as the digestive system, to perform complex functions necessary for digestion.

Eggs and sperm only have half of their parents' genetic information because they undergo a process called meiosis, where the number of chromosomes is halved. In humans, the normal number of chromosomes is 46, with 23 coming from each parent. Therefore, eggs and sperm have 23 chromosomes.

Chloroplasts are the structures in a plant cell that contain pigments, such as chlorophyll, which absorb energy from sunlight during the process of photosynthesis. This energy is then used to convert carbon dioxide and water into glucose, a sugar molecule that serves as a source of energy for the plant. Therefore, chloroplasts play a crucial role in capturing and converting solar energy into chemical energy in the form of sugar molecules.

A group of atoms that are bonded together is called a molecule. This is because molecules are formed when two or more atoms chemically combine and share electrons. These bonded atoms can be the same element or different elements. Molecules can exist as individual units or combine to form larger structures. In contrast, an atom is the smallest unit of matter that retains the properties of an element, a tissue is a group of cells that work together to perform a specific function, and a cell is the basic structural and functional unit of all living organisms.

The cell membrane is found in both plant and animal cells. It is a thin, flexible barrier that surrounds the cell and controls the movement of substances in and out of the cell. It is composed of a phospholipid bilayer with embedded proteins, and it helps maintain the cell's shape, protect the cell, and regulate the transport of molecules. While plant cells also have a cell wall and chloroplasts, which are responsible for photosynthesis, these structures are not found in animal cells. Thylakoids are membrane structures found within chloroplasts, so they are not present in both plant and animal cells.

A plant cell contains both a cell wall and a nucleus. The cell wall provides structural support and protection to the cell, while the nucleus contains the genetic material and controls the cell's activities. Animal cells do not have a cell wall, viruses do not have a nucleus, and bacteria have a cell wall but lack a true nucleus. Therefore, the plant cell is the only option that fits the given criteria.

Carbohydrates are the main energy source for most living things. They are broken down into glucose, which is then used by cells to produce ATP, the molecule that provides energy for cellular processes. Carbohydrates are found in various forms such as sugars, starches, and fibers, and they are abundant in foods like grains, fruits, and vegetables. Proteins, nucleic acids, and tissues are important components of living organisms, but they do not serve as the primary energy source.

The reproductive system is not required for survival because its main function is to produce offspring and ensure the continuation of the species. While it is essential for the survival of the species as a whole, an individual can live a full and healthy life without reproducing. On the other hand, the circulatory system, digestive system, and respiratory system are all vital for sustaining life by providing oxygen, nutrients, and eliminating waste products.

A population refers to a group of the same organism living in the same place. It represents the individuals of a particular species that inhabit a specific area and interact with each other. This term is used to describe the number, density, and distribution of organisms within a given ecosystem. It is a fundamental concept in ecology and is crucial for understanding the dynamics and interactions within a species.

The circulatory system is responsible for distributing oxygen and nutrients to cells throughout the body. It consists of the heart, blood vessels, and blood. The heart pumps oxygen-rich blood to the body's tissues through a network of blood vessels, including arteries, veins, and capillaries. This allows oxygen and nutrients to be delivered to cells, while waste products like carbon dioxide are removed. The respiratory system, on the other hand, is responsible for the exchange of gases, particularly oxygen and carbon dioxide, between the body and the external environment. The reproductive system is involved in the production of offspring, and the nervous system is responsible for transmitting signals throughout the body.

Living things respond to stimuli, which are changes in their environment that they can detect and react to. This response allows them to adapt and survive in their surroundings. Stimuli can be internal or external, such as temperature changes, light, sound, or chemical signals. By responding to stimuli, living organisms can adjust their behavior, physiology, or morphology to maintain homeostasis and ensure their survival and reproduction. Evolution and reproduction are important aspects of living things, but they are not the specific process by which living organisms respond to their environment.

A unicellular organism is made up of one cell. This means that the entire organism consists of only a single cell, which carries out all the necessary functions for its survival. Unlike multicellular organisms, unicellular organisms do not have specialized tissues or cells that perform specific functions. Instead, they rely on their single cell to carry out all the necessary processes such as reproduction, metabolism, and response to stimuli.

The nucleus is found in eukaryotic cells but not in prokaryotic cells. The nucleus is a membrane-bound organelle that contains the cell's DNA and is responsible for controlling the cell's activities. In prokaryotic cells, the DNA is not contained within a nucleus but instead floats freely in the cytoplasm. Therefore, the presence of a nucleus is a characteristic feature that distinguishes eukaryotic cells from prokaryotic cells.

Osmosis is the correct answer because it refers to the movement of water across a selectively permeable membrane. In osmosis, water molecules move from an area of lower solute concentration to an area of higher solute concentration, in order to equalize the concentration on both sides of the membrane. This process is essential for maintaining the balance of water and solutes in cells and is involved in various biological processes. Metabolism, exocytosis, and diffusion are not specifically related to the movement of water across a selectively permeable membrane.

Glucose required for cellular respiration comes from food. Food contains carbohydrates, which are broken down into glucose during digestion. Glucose is then transported to cells where it is used as a source of energy in cellular respiration. The process of cellular respiration involves breaking down glucose molecules to produce ATP, the energy currency of cells. Therefore, food is the source of glucose needed for cellular respiration.

The cytoskeleton is a cellular structure that provides shape and structure to cells. It is made up of protein filaments that form a network throughout the cell, giving it structural support. Additionally, the cytoskeleton is involved in cell movement by enabling the cell to change shape and move its components. It plays a crucial role in various cellular processes such as cell division, cell signaling, and transport of materials within the cell.

Exocytosis is the process by which cells use energy to move large particles out of the cell. During exocytosis, vesicles containing the particles fuse with the cell membrane and release their contents outside the cell. This process is essential for the secretion of substances such as hormones, neurotransmitters, and digestive enzymes. It allows the cell to eliminate waste products or release substances into the extracellular environment.

Cells are the basic building blocks of all living organisms. They are made up of various molecules such as proteins, lipids, carbohydrates, and nucleic acids. These molecules come together to form the different structures and functions within a cell. Therefore, the correct answer is molecules.

The lungs are classified as an organ because they are composed of different types of tissues that work together to carry out a specific function, which is the exchange of oxygen and carbon dioxide. Organs are made up of multiple tissues that are organized in a specific way to perform a particular function. In the case of the lungs, they contain tissues such as epithelial tissue, connective tissue, and smooth muscle tissue that enable the process of respiration. Therefore, the lungs are considered an organ rather than a single cell or tissue.

The nucleus is considered the "control center" of the cell because it contains the cell's genetic material, specifically the DNA. It regulates the cell's activities by controlling the synthesis of proteins through the process of transcription and translation. Additionally, the nucleus plays a crucial role in cell division by coordinating the replication and distribution of DNA during mitosis and meiosis. Overall, the nucleus is responsible for maintaining the cell's genetic integrity and controlling its functions.

The cell membrane is found in all cells. It is a thin, flexible barrier that surrounds the cell and separates the internal environment from the external environment. It controls the movement of substances in and out of the cell, allowing nutrients to enter and waste products to exit. The cell membrane is essential for maintaining the cell's shape, protecting it from the outside environment, and facilitating communication with other cells. Unlike chloroplasts, cell walls, and nuclei, which are only found in specific types of cells, the cell membrane is a universal feature of all cells.

Koalas are an example of a consumer because they rely on the eucalyptus tree for shelter and feed on its leaves. As consumers, they obtain their energy by consuming other organisms, in this case, the leaves of the eucalyptus tree. Autotrophs, on the other hand, are organisms that can produce their own food through photosynthesis or chemosynthesis. Prokaryotes are single-celled organisms that lack a nucleus, and producers are typically autotrophs that produce food for other organisms.

Plants capture energy from the sun through a process called photosynthesis. During photosynthesis, plants use chlorophyll to convert carbon dioxide and water into glucose (sugar) and oxygen. Oxygen and chlorophyll are not directly involved in the conversion process, while oxygen and water or oxygen and carbon dioxide do not result in the production of glucose. Therefore, the correct answer is carbon dioxide and water.

Plants require sunlight, carbon dioxide, and water to perform photosynthesis. Oxygen is not required by plants for photosynthesis, as it is actually produced as a byproduct of the process. During photosynthesis, plants convert carbon dioxide and water into glucose and oxygen, using sunlight as the energy source. Therefore, oxygen is not needed for the photosynthesis process itself.

Mitochondria are responsible for releasing energy in an animal cell. They are often referred to as the "powerhouses" of the cell because they produce the majority of the cell's energy in the form of ATP through a process called cellular respiration. Mitochondria have their own DNA and are able to generate energy by breaking down glucose and other molecules. This energy is essential for the cell to carry out its various functions and activities.

A graduated cylinder is used to measure the volume of an irregularly shaped object because it can accurately measure the volume of liquids and solids. It has markings on the side that indicate the volume, allowing for precise measurements. A ruler, triple beam balance, and meter stick are not suitable for measuring volume as they are used for measuring length, weight, and distance respectively.

Lysosomes are organelles that contain enzymes responsible for breaking down and digesting waste materials and cellular debris. They function as the cell's recycling center, absorbing and breaking down materials that are no longer needed by the cell. This process helps maintain the overall health and cleanliness of the cell by eliminating waste and recycling useful components. Mitochondria are responsible for energy production, vacuoles primarily store water and other substances, and ribosomes are involved in protein synthesis. Therefore, lysosomes are the correct answer for this question.

The cell membrane is the structure in the cell that regulates the movement of substances into and out of the cell. It acts as a selectively permeable barrier, allowing certain molecules to pass through while preventing others from entering or leaving the cell. This is crucial for maintaining the cell's internal environment and controlling the exchange of nutrients, waste products, and signaling molecules with the external environment. The cell membrane is composed of a phospholipid bilayer with embedded proteins that facilitate the transport of specific molecules across the membrane.

The displacement method is used to measure the volume of an irregular solid. This method involves placing the solid in a graduated cylinder filled with a known volume of liquid, such as water. The difference in the volume of the liquid before and after adding the solid gives the volume of the solid. This method is particularly useful for objects that do not have regular shapes or cannot be easily measured using other methods like the triple beam balance, density, or mass.

A prokaryote is not an example of a molecule because it is a single-celled organism that lacks a nucleus and other membrane-bound organelles. It is a living organism, not a chemical compound made up of atoms bonded together. Lipid, protein, and DNA are all examples of molecules as they are composed of atoms bonded together to form a specific chemical structure.

The density of an object is calculated by dividing its mass by its volume. In this case, the ball has a mass of 10 g and a volume of 2 mL. Dividing 10 g by 2 mL gives us a density of 5 g/mL.