Chapter 6: A Tour Of The Cell

The nucleus is a membrane-bound organelle found in both plant and animal cells. Its main function is to store and protect the genetic material, which is DNA. DNA contains the instructions for the cell's activities and is essential for the cell's growth, development, and reproduction. The nucleus also regulates the activities of the cell and controls the synthesis of proteins. Therefore, the correct answer is that the nucleus stores genetic material, DNA.

The correct answer is "has nucleus and other organelles like protists, fungi, plants and animals." Eukaryotic cells are characterized by having a nucleus, which contains the genetic material, and other membrane-bound organelles. This distinguishes them from prokaryotic cells, such as bacteria and archaea, which lack a nucleus and other organelles. Eukaryotic cells can be found in various organisms, including protists, fungi, plants, and animals.

The correct answer is that the phospholipid bilayer is a structure of phospholipid membranes that are formed by a 2 layer sandwich of phospholipids. This means that the phospholipids arrange themselves in two layers, with their hydrophilic heads facing outwards and their hydrophobic tails facing inwards. This arrangement creates a barrier that is selectively permeable, allowing certain substances to pass through while blocking others. The phospholipid bilayer is a fundamental component of cell membranes and is essential for maintaining the integrity and functionality of cells.

The solution with the lower concentration of solute is called hypotonic. In a hypotonic solution, there is a higher concentration of water molecules compared to solute molecules. This causes water to move into the cells through osmosis, resulting in the cells swelling or even bursting. Hypotonic solutions are commonly used in medical settings to rehydrate patients or to prevent dehydration.

Active transport is a process in which a cell expends energy to transport molecules or ions across a membrane. This energy is required because active transport moves substances against their concentration gradient, from an area of low concentration to an area of high concentration. This process is crucial for maintaining proper cell function and homeostasis, as it allows the cell to accumulate substances that are needed in higher concentrations inside the cell.

Flagella are long, thin whip-like structures made of protein that enable some cells to move. They act as a propeller, allowing the cell to swim or move in a fluid environment. In addition to movement, flagella also play a role in moving materials along pathways within the cell. They are found in various organisms, including bacteria, archaea, and eukaryotes, and are essential for their motility and function.

Exocytosis is a cellular process in which vesicles, small membrane-bound sacs, fuse with the cell membrane and release their contents outside of the cell. This process is responsible for moving large particles, such as proteins or waste materials, out of the cell. It is a vital mechanism for various cellular functions, including secretion, neurotransmitter release, and removal of cellular waste.

Equilibrium refers to a state in which the concentration of a particle is equal on both sides of a membrane. This means that there is no net movement of particles across the membrane, as the concentration gradient is balanced. In this state, the particles are evenly distributed and there is no further movement or change in concentration.

Diffusion is the process by which particles move from an area of higher concentration to an area of lower concentration. This movement occurs due to the random motion of particles. The particles will continue to diffuse until they are evenly distributed throughout the available space. Therefore, the statement that diffusion is a movement of particles from where they are more concentrated to where they are less concentrated is true.

An isotonic solution is one in which the concentration of solute is equal. In an isotonic solution, the concentration of solute inside and outside of the cell is balanced, resulting in no net movement of water across the cell membrane. This allows the cell to maintain its shape and normal function.

Endocytosis is a cellular process in which vesicles, small membrane-bound sacs, are formed to engulf and transport large particles or substances into the cell. This process allows the cell to take in nutrients, hormones, and other molecules from the extracellular environment. Therefore, the correct answer is "vesicles move large particles into the cell."

Prokaryotic cells are characterized by their lack of nuclei and most other organelles. They are found in bacteria and archaea. Unlike eukaryotic cells, prokaryotic cells do not have a membrane-bound nucleus and their genetic material is typically found in a single circular molecule of DNA. They also lack membrane-bound organelles such as mitochondria and endoplasmic reticulum. Prokaryotic cells are simpler in structure compared to eukaryotic cells and are typically smaller in size.

The cytoplasm is the entire region between the nucleus and the plasma membrane in both plant and animal cells. It is a gel-like substance that holds various organelles, such as mitochondria, ribosomes, and the endoplasmic reticulum. It also contains cytosol, which is a fluid that surrounds the organelles. The cytoplasm plays a crucial role in supporting the structure of the cell and facilitating various cellular processes, including protein synthesis and metabolism.

Osmosis is the process by which water molecules pass through a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration, without the need for energy input. This passive transport of water helps to equalize the concentration of solutes on both sides of the membrane, maintaining osmotic balance.

Ribosomes are responsible for protein synthesis in cells. They use the instructions encoded in DNA to build proteins. Some ribosomes are found attached to the endoplasmic reticulum, while others are free-floating in the cytoplasm. This allows for the production of proteins that are needed in different locations within the cell. Therefore, ribosomes are the correct answer to the question.

When one solution has a higher concentration of solute than another solution, we call that solution hypertonic. In a hypertonic solution, there is a greater amount of solute particles compared to the solvent particles. This causes water molecules to move from an area of lower solute concentration (hypotonic) to an area of higher solute concentration (hypertonic) through a process called osmosis. This movement of water leads to a net flow of water out of the hypotonic solution, resulting in the shrinking or shriveling of cells in the hypertonic solution.

Facilitated diffusion is a type of passive transport where certain substances are able to move across a membrane with the assistance of transport proteins. Unlike active transport, facilitated diffusion does not require any energy input from the cell. This process is selective, meaning that only specific substances are able to be transported through the membrane. In the given answer, the mention of "no energy required" and "with help from transport proteins" accurately describes the process of facilitated diffusion. The mention of "sugar" is likely referring to the fact that facilitated diffusion can also transport sugars across the membrane.

The Golgi apparatus is an organelle in the cell that is responsible for modifying, storing, and routing proteins and other chemical products to their next destination. It receives proteins from the endoplasmic reticulum, modifies them by adding sugars or lipids, and then packages them into vesicles for transport to other parts of the cell or for secretion outside the cell. The Golgi apparatus plays a crucial role in the sorting and processing of proteins, ensuring that they are delivered to the correct locations within the cell.

Passive transport refers to the movement of substances across a cell membrane without the use of energy by the cell. This type of transport occurs through diffusion, where molecules move from an area of higher concentration to an area of lower concentration. The correct answer accurately describes passive transport as diffusion across a membrane without the need for cellular energy.

Lysosomes are organelles that contain digestive enzymes responsible for breaking down nutrients and destroying harmful bacteria. These enzymes help in the digestion of various substances within the cell, including proteins, carbohydrates, and lipids. Lysosomes play a crucial role in maintaining cellular homeostasis by recycling cellular waste and eliminating foreign particles. They are involved in processes such as autophagy, where damaged organelles or proteins are engulfed and broken down. Overall, lysosomes are vital for the proper functioning and health of the cell.

Mitochondria are the site where cellular respiration occurs. Cellular respiration is the process by which cells convert glucose and oxygen into energy in the form of ATP. Mitochondria have a double membrane and their own DNA, which allows them to produce energy through aerobic respiration. This process takes place in the inner membrane of the mitochondria, where enzymes and electron transport chains are located. Therefore, mitochondria are responsible for generating the majority of ATP in cells and are considered the powerhouses of the cell.

Chloroplasts are the sites of photosynthesis in plant and algae cells. They contain chlorophyll, a green pigment that absorbs light energy, which is then used to convert carbon dioxide and water into glucose (a sugar) and oxygen. This process is essential for the survival of plants and algae, as it provides them with the energy they need to grow and thrive.

A micrograph is a photograph of the view through a microscope. It is a visual representation of what can be seen when looking through a microscope, capturing the details and structures of microscopic objects.

Vesicles are small membrane sacs that play a crucial role in transporting particles into, out of, and within a cell. These sacs are involved in processes such as endocytosis, where they bring substances into the cell, and exocytosis, where they release substances outside the cell. Vesicles also aid in the transport of molecules within the cell, allowing for the efficient movement of proteins, lipids, and other cellular components. Overall, vesicles are essential for maintaining the proper functioning and organization of a cell.

The cell theory is a fundamental principle in biology that states three main points: 1) all living things are made of cells, 2) cells are the basic unit of structure and function in living organisms, and 3) all cells come from pre-existing cells. This means that cells are not only found in animals or plants, but in all living things. Therefore, the correct answers are: all living things are made of cells, cells are the basic unit of structure and function, and all cells come from pre-existing cells.

Microtubules are straight hollow tubes of protein that provide rigidity, shape, and organization to a cell. They are essential components of the cytoskeleton and play a crucial role in various cellular processes such as cell division, cell movement, and intracellular transport. Microtubules are composed of tubulin protein subunits arranged in a cylindrical structure, giving them their characteristic tubular shape. They provide structural support to the cell and serve as tracks for the movement of organelles and vesicles within the cell. Overall, microtubules are vital for maintaining cell shape and integrity.

The pair of membranes that surrounds the nucleus is called the nuclear envelope. This envelope acts as a protective barrier for the nucleus, separating its contents from the rest of the cell. It regulates the movement of molecules in and out of the nucleus through nuclear pores. The nuclear envelope also plays a crucial role in maintaining the structural integrity of the nucleus and is involved in various cellular processes such as DNA replication and gene expression.

Microfilaments are thin, solid rods of protein that allow the cell to move or change shape. These filaments are made up of actin protein and play a crucial role in various cellular processes such as cell movement, cell division, and maintaining cell shape. They provide structural support to the cell and are involved in the formation of cellular extensions like pseudopodia and filopodia. By interacting with other proteins and motor molecules, microfilaments enable the cell to generate forces and exert movements, allowing it to change shape, migrate, and perform essential functions in processes like muscle contraction and cell locomotion.

Membrane proteins play crucial roles in various cellular functions. They can carry out chemical reactions by acting as enzymes or catalysts, facilitating important biochemical processes. Additionally, they help cells communicate and recognize each other through cell signaling and cell adhesion molecules, enabling coordination and interaction between cells. Furthermore, membrane proteins are responsible for transporting materials across the membrane, allowing the movement of ions, nutrients, and waste products in and out of the cell.

The plasma membrane is a thin outer covering of a cell that defines the boundary of the cell. It regulates the movement of chemicals into and out of the cell. It is found in both plant and animal cells and holds organelles.