Chapter 7 Honor Biology Test

The principle of the cell theory states that all living things are made of cells, cells are the basic unit of life, and all cells are produced by existing cells. The statement "very few cells reproduce" contradicts this principle, as it implies that most cells do not have the ability to reproduce.

The cell wall is a rigid structure that surrounds the cell membrane in plant cells, bacteria, fungi, and some protists. Its main function is to provide support and protection to the cell. It helps maintain the shape of the cell and protects it from external forces. The cell wall also prevents the cell from bursting or collapsing under pressure. Therefore, the correct answer is "support and protect the cell".

Eukaryotes contain a nucleus. The nucleus is a membrane-bound organelle that houses the genetic material (DNA) of the cell. It is found in cells of organisms belonging to the domain Eukarya, which includes animals, plants, fungi, and protists. Prokaryotes, such as bacteria, do not have a nucleus. Instead, their genetic material is found in a region of the cell called the nucleoid. Organelles, on the other hand, are structures within cells that perform specific functions, but they are not cells themselves and therefore do not have a nucleus.

The nucleus is important to cells because it contains coded instructions for making proteins. These instructions are stored in the form of DNA, which is transcribed into RNA and then translated into proteins. Proteins are essential for various cellular processes, including growth, development, and functioning. Therefore, the presence of a nucleus and its ability to store and transcribe genetic information is crucial for the survival and functioning of cells.

The cytoskeleton is a network of protein filaments within a cell that provides structural support and helps maintain the cell's shape. It acts as an internal scaffold, allowing the cell to maintain its integrity and resist deformation. Additionally, the cytoskeleton is involved in various cellular processes such as cell division, cell movement, and intracellular transport. Therefore, the function of the cytoskeleton that is described in the given answer is accurate.

Chloroplasts are the organelles responsible for photosynthesis in plant cells. They contain chlorophyll, which captures sunlight and converts it into energy. Animal cells do not have chloroplasts because they obtain energy through other means, such as consuming food. Therefore, chloroplasts are only found in plant cells and not in animal cells.

The correct answer is "specialized to perform different tasks". In multicellular organisms, cells work together and have specific roles to carry out different functions in the organism. This specialization allows for the efficient functioning of the organism as a whole. Each type of cell is adapted to perform a specific task, such as muscle cells for movement or nerve cells for transmitting signals. This specialization allows multicellular organisms to have a higher level of complexity and functionality compared to unicellular organisms, whose cells are more general and perform all necessary functions.

The heart is an example of an organ because it is a specialized structure composed of different tissues that work together to perform a specific function. In this case, the heart is responsible for pumping blood throughout the body, which is essential for delivering oxygen and nutrients to the cells and removing waste products.

The cell theory applies to all of the above options, including plants and animals, bacteria, and multicellular organisms. The cell theory states that all living organisms are composed of cells, cells are the basic units of structure and function in living organisms, and cells come from pre-existing cells. This theory applies to all living organisms, regardless of their complexity or type.

The cell membrane serves as the cell's boundary from its environment. It is a selectively permeable barrier that allows certain substances to enter and exit the cell while preventing others from doing so. The cell membrane is composed of a phospholipid bilayer embedded with proteins that help regulate the movement of molecules in and out of the cell. This structure is essential for maintaining homeostasis and protecting the cell's internal environment.

Prokaryotes lack a nucleus. Prokaryotic cells are characterized by the absence of a membrane-bound nucleus. Unlike eukaryotic cells, which have a well-defined nucleus that houses the genetic material, prokaryotic cells have a nucleoid region where the genetic material is located. This genetic material, usually in the form of a single circular DNA molecule, floats freely in the cytoplasm of the prokaryotic cell. Therefore, the correct answer is a nucleus.

The stomach is an organ of the digestive system because it plays a crucial role in the digestion of food. It receives food from the esophagus and breaks it down using acid and enzymes. The stomach also helps in the absorption of certain nutrients and regulates the release of partially digested food into the small intestine. The other options, muscle cell, nerve tissue, and epithelial tissue, are not organs of the digestive system but rather types of tissues found in various organs and systems of the body.

The cell membrane acts as a selectively permeable barrier, allowing certain substances to enter and leave the cell while preventing others from doing so. This regulation of material transport is crucial for maintaining the internal environment of the cell and ensuring that it can function properly. The cell membrane achieves this through various mechanisms such as protein channels and transporters that facilitate the movement of specific molecules across the membrane.

The cytoplasm is a jelly-like substance that surrounds the nucleus in a cell. It contains various organelles and is the site of many cellular processes, but it does not contain the nucleus itself. The nucleus is a membrane-bound organelle that houses the genetic material of the cell, which is DNA. The nucleolus is a structure within the nucleus that is involved in the production of ribosomes. Chromatin refers to the DNA and proteins that make up the chromosomes in the nucleus. Therefore, the correct answer is cytoplasm, as it is not found within the nucleus.

Active transport requires input of energy from the cell in order to move particles against their concentration gradient. This process involves the use of specific carrier proteins in the cell membrane that pump molecules or ions across the membrane, creating a concentration gradient. This energy requirement distinguishes active transport from other forms of particle transport such as diffusion, facilitated diffusion, and osmosis, which do not require energy input from the cell.

The correct answer is cell, tissue, organ, organ system. This sequence represents the levels of organization in a multicellular organism from the simplest level to the most complex level. The cell is the basic unit of life and is the simplest level of organization. Tissues are formed by a group of similar cells working together to perform a specific function. Organs are made up of different types of tissues working together to carry out a specific function. Finally, organ systems are made up of multiple organs working together to perform a particular function for the organism as a whole.

The nucleus is responsible for storing DNA, which carries the genetic information of an organism. It also controls most of the cell's processes by regulating gene expression and directing the synthesis of proteins. Additionally, the nucleus contains the information needed to make proteins, as it houses the DNA that codes for the production of proteins through the process of transcription and translation. Therefore, all of the given options are correct functions of the nucleus.

Bacteria are prokaryotes because they lack a nucleus and other membrane-bound organelles. Prokaryotes are single-celled organisms that have a simple cell structure, and bacteria are one of the main groups of prokaryotes. Animals and plants, on the other hand, are eukaryotes, which means they have a nucleus and other membrane-bound organelles. Therefore, the correct answer is bacteria as they are the only organism listed that is a prokaryote.

The work of Scheleiden and Schawann is summarized by the statement that all plant and animals are made of cells. This means that both plants and animals are composed of basic structural units called cells. This discovery was significant in establishing the cell theory, which states that cells are the fundamental building blocks of all living organisms.

Animals do not have a cell wall. While both fungi and plants have cell walls, animals have a different cell structure called a cell membrane. The cell wall provides structural support and protection for cells, but animals have evolved to have more flexible cell membranes instead. This allows for greater mobility and flexibility in animal cells compared to plant and fungal cells. Therefore, animals do not possess a cell wall.

Osmosis is the correct answer because it refers to the process of water diffusion 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 solute concentration on both sides of the membrane. This process is passive and does not require energy. Active transport, facilitated diffusion, and osmotic pressure are not the correct answers as they refer to different processes.

The mitochondrion is responsible for converting the chemical energy stored in food into compounds that are more convenient for the cell to use. This process is known as cellular respiration, where glucose and oxygen are broken down to produce ATP, the main energy currency of the cell. The mitochondrion has an inner membrane that contains enzymes involved in the reactions of cellular respiration, allowing for the efficient production of ATP.

Robert Hooke was one of the first people to identify and see cork cells. In 1665, he used a compound microscope to observe thin slices of cork and noticed small, box-like structures that he called "cells". Hooke's discovery of cells in cork was significant because it marked the first time that cells were observed and described, leading to the development of the cell theory. This theory states that all living organisms are composed of cells, which are the basic units of life.

Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. This occurs because molecules naturally tend to spread out and become evenly distributed. Therefore, they move from an area where there are more of them to an area where there are fewer. This process continues until equilibrium is reached, where the concentration is equal throughout the entire system.

Microtubules and microfilaments are the structures that carry out cell movement. Microtubules are long, hollow tubes made up of protein subunits called tubulin, and they provide structural support and act as tracks for the movement of organelles and vesicles within the cell. They also play a crucial role in cell division, forming the mitotic spindle that helps separate chromosomes during mitosis. Microfilaments, on the other hand, are thin, solid filaments made up of actin protein. They are involved in various cellular processes, including cell shape changes, cell migration, and muscle contraction. Together, microtubules and microfilaments contribute to the dynamic movement and organization of cells.

Eukaryotes usually contain specialized organelles, genetic material, and a nucleus. This is because eukaryotic cells are more complex than prokaryotic cells and have a membrane-bound nucleus that houses the genetic material. Additionally, eukaryotes have various specialized organelles that perform specific functions within the cell, such as mitochondria for energy production and Golgi apparatus for protein processing. Therefore, the correct answer is "all of the above" as all these characteristics are commonly found in eukaryotic cells.

Cell specialization refers to the process by which cells in a multicellular organism differentiate and acquire specific functions to perform different tasks within the organism. In a multicellular organism, different cells have specific roles and jobs that contribute to the overall functioning of the organism. This specialization allows for the efficient functioning of the organism as a whole, as different cells can perform specific tasks and work together in a coordinated manner. Unicellular organisms, on the other hand, do not have specialized cells as they are composed of a single cell that performs all necessary functions.

When an animal cell is surrounded by fresh water, the concentration of solutes inside the cell is higher than the concentration of solutes in the surrounding water. This creates a concentration gradient, and according to osmosis, water molecules will move from an area of lower solute concentration (the fresh water) to an area of higher solute concentration (inside the cell). As a result, water will move into the cell, causing it to swell and potentially burst. Therefore, the correct answer is "water to move into the cell".

A group of similar cells that perform a particular function is called a tissue. Tissues are specialized groups of cells that work together to perform specific functions in the body. They can be found in various organs and organ systems, and each type of tissue has a unique structure and function. Examples of tissues include muscle tissue, nervous tissue, and epithelial tissue.

The correct answer traces the path of a protein in the cell from the rough endoplasmic reticulum to the Golgi apparatus and then to be released from the cell. This sequence reflects the process of protein synthesis and trafficking in eukaryotic cells. Proteins are synthesized by ribosomes on the rough endoplasmic reticulum, then transported to the Golgi apparatus for modification, sorting, and packaging. Finally, the proteins are released from the cell through various mechanisms such as exocytosis.

The given options describe different types of specialized cells. A pancreatic cell that produces protein-digesting enzymes is an example of a specialized cell because it has a specific function of producing enzymes for digestion. A red blood cell that carries oxygen is also specialized because its main function is to transport oxygen throughout the body. Muscle cells that control movement of materials in the body are specialized cells because they have the specific function of controlling movement. However, a prokaryotic cell that carries out photosynthesis is not an example of cell specialization because prokaryotic cells are not typically specialized and photosynthesis is a general metabolic process that many prokaryotic cells can perform.

The cell membrane contains channels and pumps that help move materials from one side to the other. These channels and pumps are made of proteins. Proteins are the main components of the cell membrane and play a crucial role in regulating the movement of molecules and ions across the membrane. They form channels that allow specific substances to pass through and pumps that actively transport molecules against their concentration gradient. Proteins also contribute to the structure and stability of the cell membrane.

An organ system is a group of organs that work together to perform a specific function. This means that each organ within the system has a specific role to play in order to carry out a particular function. The organs coordinate their efforts and work in harmony to achieve a common goal. This specialization and collaboration allow the organ system to efficiently perform its designated function, whether it be digestion, circulation, or any other vital process in a multicellular organism.

Ribosomes are the structures found in the cytoplasm. They are responsible for protein synthesis and are composed of ribosomal RNA (rRNA) and proteins. They can be found free in the cytoplasm or attached to the endoplasmic reticulum. Chromatin, on the other hand, is the material that makes up chromosomes and is found in the nucleus. The cell wall is a rigid structure found in plant cells, while the nucleolus is a small, dense region within the nucleus involved in ribosome synthesis. Therefore, the correct answer is ribosome.

The cytoskeleton is a network of protein filaments that provides structural support to the cell and helps in various cellular processes. It aids in cell movement by providing tracks for motor proteins to move along. It also helps in maintaining the cell's shape by providing structural stability. Additionally, the cytoskeleton assists in the movement of organelles within the cell by acting as a scaffold. However, preventing chromosomes from separating is not a function of the cytoskeleton. This process is primarily regulated by the spindle apparatus during cell division.

When the concentration of molecules on both sides of a membrane is the same, it means that there is an equal amount of molecules on each side. In this scenario, there is no concentration gradient, which is the driving force for molecules to move across a membrane. Therefore, the molecules will move across the membrane in both directions, as there is no net movement of molecules from one side to the other.

Electron microscopes use a beam of electrons instead of light to magnify and visualize objects. This allows them to achieve much higher resolution and reveal details that are 1000 times smaller than those visible in light microscopes.

The question asks for the type of tissue that is NOT included in the given options. Nerve, connective, and muscle tissues are all types of tissues found in the body. However, digestive tissue is not a recognized type of tissue. The digestive system is composed of different organs and tissues, such as the stomach and intestines, but it does not refer to a specific type of tissue. Therefore, the correct answer is digestive.

Diffusion occurs because molecules constantly move and collide with each other. This movement and collision causes the molecules to spread out and become evenly distributed throughout a solution. As a result, the concentration of a solution is never the same throughout.

A scanning electron microscope (SEM) is capable of producing three-dimensional images of cells. Unlike a transmission electron microscope (TEM), which uses a beam of electrons transmitted through a thin section of the sample, an SEM scans the surface of the sample with a focused beam of electrons. This scanning process allows for the collection of detailed information about the surface topography of the cells, resulting in three-dimensional images. Therefore, the correct answer is scanning electron microscope.

The mitochondrion is responsible for breaking down food into molecules that the cell can use. It is often referred to as the "powerhouse" of the cell because it produces energy in the form of ATP through a process called cellular respiration. This organelle contains enzymes that break down carbohydrates, fats, and proteins into smaller molecules that can be utilized by the cell for various functions. Overall, the mitochondrion plays a crucial role in providing energy for the cell's activities.

Researchers use fluorescent labels and light microscopy to track the movement of molecules within cells. By labeling specific molecules with fluorescent markers and using laser beams to scan the cells, researchers can observe and study the movement and behavior of these molecules in real-time. This technique allows for a better understanding of cellular processes and can provide valuable insights into cell function and development.