A.P. Biology Chapter 6 (Cells)

The nucleus is an organelle that contains chromatin or chromosomes. This is where the genetic material of a cell is stored, including DNA and RNA. The nucleus is surrounded by a double membrane called the nuclear envelope, which helps protect the genetic material and regulate the passage of molecules in and out of the nucleus. The chromatin or chromosomes within the nucleus carry the instructions for the cell's growth, development, and reproduction.

Bound ribosomes are attached to the endoplasmic reticulum (ER), while free ribosomes are not attached to any specific organelle and float freely in the cytoplasm. This difference in location affects the functions of the ribosomes. Bound ribosomes are involved in the synthesis of proteins that are destined to be secreted or inserted into the cell membrane, while free ribosomes primarily synthesize proteins that function within the cytoplasm.

Chloroplasts are used for photosynthesis, the process by which plants convert sunlight, water, and carbon dioxide into glucose and oxygen. Chloroplasts contain chlorophyll, a pigment that absorbs sunlight and allows plants to capture energy from the sun. This energy is then used to produce glucose, which is the main source of energy for plants. Therefore, chloroplasts play a crucial role in the production of food and energy for plants.

The correct answer is "Nuclear envelope". The nuclear envelope is a double membrane structure that surrounds the nucleus of a cell. It separates the contents of the nucleus from the cytoplasm and regulates the passage of molecules in and out of the nucleus. It is also known as the nuclear membrane.

Eukaryotes are the largest cells, ranging in size from 10-100 micrometers. Eukaryotic cells are found in plants, animals, fungi, and protists. They contain a nucleus and other membrane-bound organelles, allowing for more complex cellular functions. Mycoplasms, regular bacteria, and none of the above are not the largest cells.

Ribosomes are responsible for the synthesis of proteins in the cell. They are small organelles that read the genetic information stored in the DNA and use it to assemble amino acids into chains, which then fold into functional proteins. This process, known as translation, occurs in the cytoplasm of the cell. Therefore, the correct answer is "Help create proteins."

Mitochondria are used for cellular respiration. They are the powerhouses of the cell, producing energy in the form of ATP through a series of metabolic reactions. This process involves breaking down glucose and other molecules to release energy that can be used by the cell. Mitochondria have their own DNA and are believed to have originated from ancient bacteria that were engulfed by a eukaryotic cell. They are found in most eukaryotic cells and are essential for the survival and functioning of the cell.

When the Golgi adds a carbohydrate to a protein, it forms a glycoprotein. Glycoproteins are proteins that have a carbohydrate attached to them. This process, known as glycosylation, is important for protein folding, stability, and function. Glycoproteins play crucial roles in various biological processes, including cell-cell recognition, immune response, and cell signaling. Therefore, the correct answer is glycoprotein.

The Rough Endoplasmic Reticulum (RER) is a network of membrane-bound sacs and tubules found in the cytoplasm of eukaryotic cells. It is called "rough" because it is studded with ribosomes on its surface. The ribosomes on the RER are responsible for protein synthesis. The RER is located close to the nucleus, allowing for efficient transport of newly synthesized proteins to other parts of the cell.

The fourth and final step in the endomembrane system is when the vacuole leaves the Golgi. At this stage, the vacuole may either fuse with other vacuoles or leave the cell altogether. This step marks the completion of the transport and modification of proteins and other molecules within the endomembrane system.

The central vacuole is located in plants. Plants have a large central vacuole that takes up most of the space inside the cell. The central vacuole stores water, nutrients, and waste products. It also helps maintain the turgor pressure in plant cells, which is important for cell structure and support. Animals, bacteria, and fresh water protists do not have a central vacuole like plants do.

The peroxisome is responsible for detoxifying harmful substances in the cell. It contains enzymes that break down toxic molecules and convert them into less harmful compounds. This process helps to protect the cell from damage caused by toxins and maintain cellular homeostasis. Cellular respiration is the process by which cells produce energy, photosynthesis is the process by which plants convert sunlight into energy, and transport proteins are involved in the movement of molecules across cell membranes.

The incoming part of the Golgi is known as the cisforming part. This section of the Golgi apparatus receives materials from the endoplasmic reticulum (ER) for further processing and modification. It is responsible for sorting and directing these materials to the appropriate compartments within the Golgi apparatus for further processing and transport. The cisforming part plays a crucial role in the intracellular trafficking and modification of proteins and lipids.

Cell fractionation is a process of separating different components of cells based on their size, density, and other physical properties. In this case, putting cells in a blender and then centrifuging them at high speeds helps to break down the cells and separate their components based on their density. This allows for further analysis of the different cellular components, such as organelles or proteins, in biochemical studies.

The first step in the endomembrane system is when ribosomes inject protein into the lumen of the ER. This process occurs during protein synthesis, where ribosomes attached to the ER membrane synthesize proteins and transport them into the ER lumen. This step is crucial for the proper folding and modification of proteins before they are transported to their final destinations within the cell or secreted outside of the cell.

The correct answer is "Cristae." Cristae are the folds found on the inside of a mitochondria. These folds increase the surface area of the inner membrane, allowing for more space for chemical reactions to occur and ultimately increasing the efficiency of ATP production.

The correct answer is the transmaturing part. The Golgi apparatus is composed of several compartments, including the cis-Golgi network, medial-Golgi, and trans-Golgi network. The transmaturing part refers to the trans-Golgi network, which is responsible for modifying and sorting proteins and lipids before they are transported to their final destinations within the cell or secreted outside of the cell. Therefore, the transmaturing part is the outgoing part of the Golgi.

Cilia are short and plentiful, while flagella are long and sparse.

The Smooth Endoplasmic Reticulum (SER) is located farthest from the nucleus and does not have ribosomes attached to its surface. This organelle is involved in various functions such as lipid synthesis, detoxification, and calcium storage. The absence of ribosomes on its surface allows the SER to have a smoother appearance compared to the Rough Endoplasmic Reticulum (RER), which is covered with ribosomes.

The third step in the endomembrane system is when the vacuole fuses with the Golgi, where carbohydrates or lipids are added.

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Intermediate filaments are a type of cytoskeletal protein that are responsible for maintaining the structural integrity of cells. They provide mechanical support and help to anchor organelles within the cell. Unlike microfilaments and microtubules, which have a dynamic nature, intermediate filaments are more stable and less involved in cellular movement. Therefore, the correct answer is "Used to maintain cell shape and anchor organelles."

Microtubules are hollow structures that play important roles in cellular division and the movement of cilia and flagella. They provide structural support to the cell and help in the organization and movement of organelles. During cellular division, microtubules form the spindle apparatus, which helps in the separation of chromosomes. In cilia and flagella, microtubules form the core structure and provide the necessary support for their movement. Therefore, the correct answer is "Hollow, used in cellular division and cilia/flagella."

A granum is a stack of thylakoids. Thylakoids are membrane-bound compartments found in chloroplasts, which are the organelles responsible for photosynthesis in plants. Thylakoids contain the pigment chlorophyll, which captures light energy and converts it into chemical energy. These thylakoids are arranged in stacks called granum, which allows for efficient light capture and energy production during photosynthesis.

Ribosomes are responsible for putting primary proteins into the lumen of the endoplasmic reticulum (ER) to become quarternary proteins. This process is essential for the proper folding and modification of proteins before they are transported to their final destinations within the cell or secreted outside of the cell. The ribosomes act as molecular machines that read the genetic information in mRNA and synthesize proteins accordingly. By targeting the proteins to the ER, ribosomes ensure that they undergo further processing and folding in the ER lumen to acquire their functional quarternary structure.

The SER, or smooth endoplasmic reticulum, is responsible for making lipids and detoxifying poison. It does not play a role in making proteins, carbohydrates, or nucleic acids.

Mycoplasms are the smallest cells because they have a size range of 0.1-1 micrometers. Regular bacteria and eukaryotes are larger in size compared to mycoplasms. Therefore, the correct answer is mycoplasms.

Regular bacteria are the cells that are 1-10 micrometers in size. Mycoplasms are also bacteria but they are smaller in size, typically ranging from 0.2-0.3 micrometers. Eukaryotes, on the other hand, include cells that are much larger than regular bacteria, such as animal and plant cells. Therefore, the correct answer is regular bacteria.

When the Golgi adds a lipid to a protein, it forms a lipoprotein. Lipoproteins are complex molecules that consist of both proteins and lipids. The addition of lipids to proteins helps in their transportation and stability within the body. Lipoproteins play a crucial role in lipid metabolism and are involved in various physiological processes such as the transport of cholesterol and triglycerides in the bloodstream. Therefore, lipoprotein is the correct term to describe the process of adding a lipid to a protein by the Golgi.

Plasmodesmata are cellular junctions that are found only in plant cells. They are responsible for connecting the cytoplasm of two adjacent cells across their cell walls. Therefore, both options A and B are correct explanations for what plasmodesmata are.

The microtubule arrangement of a cross section of a cilia/flagella is 9+2. This means that there are nine peripheral microtubule doublets surrounding a central pair of microtubules. This arrangement provides structural support and allows for the movement of cilia and flagella.

Drug use can increase the activity of the serotonin reuptake transporter (SER), leading to an increase in the reuptake of serotonin. This can result in higher levels of serotonin being taken back up into the presynaptic neuron, reducing the amount available in the synaptic cleft for binding to postsynaptic receptors. As a result, drug use can lead to a decrease in serotonin signaling and potentially affect mood, behavior, and other physiological processes regulated by serotonin.

Chromosomes in the nucleus refer to the state of DNA during cell division. When DNA is condensed, it means that it is tightly packed and organized into structures called chromosomes. This occurs during cell division when the DNA needs to be replicated and distributed equally to daughter cells. Therefore, the correct answer is that chromosomes in the nucleus mean that DNA is condensed and dividing.

A compound light microscope is used for thin sections because it allows for high magnification and resolution of the sample. This type of microscope uses visible light to illuminate the sample, which is particularly useful for thin sections where the sample is transparent or semi-transparent. The compound light microscope has multiple lenses that work together to magnify the image, allowing for detailed examination of the thin section. In contrast, a stereoscope is used for viewing larger and solid objects in three dimensions, while TEM and SEM are electron microscopes that use electron beams instead of light for imaging.

A Transmission Electron Microscope (TEM) is used for thin sections because it uses a beam of electrons to pass through the sample, allowing for high-resolution imaging of the internal structure of the specimen. This type of microscope is capable of producing detailed images of thin sections at the nanometer scale, making it ideal for studying the ultrastructure of biological samples or examining thin slices of materials. In contrast, a Scanning Electron Microscope (SEM) is used for studying the surface of a sample rather than its internal structure.

A lumen refers to free space. It is a term used to describe the cavity or empty space within a tubular structure such as a blood vessel or a duct. In other words, it is the open area or channel within a structure where fluid or air can flow. It is not a type of membrane or protein, nor does it refer to a filled-in space.

Thylakoids are the folds in the stroma of a chloroplast. They are flattened membrane sacs that contain chlorophyll and other pigments, as well as the proteins necessary for photosynthesis. Thylakoids are arranged in stacks called grana, and they play a crucial role in capturing light energy and converting it into chemical energy through the process of photosynthesis.

The maximum magnification of a TEM (Transmission Electron Microscope) is 1,000,000x. This means that the microscope can magnify an image up to one million times its original size. This high magnification allows for detailed observation of very small objects and structures, making the TEM a powerful tool in scientific research and analysis.

The inner, most important part of a mitochondria is called the matrix. The matrix is the space inside the inner membrane of the mitochondria where many of the metabolic reactions take place. It contains enzymes that are involved in the citric acid cycle and the production of ATP, the main source of energy for the cell. The matrix also contains DNA, ribosomes, and other components necessary for the mitochondria to function properly.

The extracellular matrix is a complex network of proteins and carbohydrates that surrounds and supports cells in tissues. It functions as the animal equivalent of a cell wall, providing structural support and stability to cells. Additionally, the extracellular matrix plays a crucial role in cell recognition and communication, as it contains molecules that can interact with cell surface receptors and facilitate cell signaling. Therefore, both options A and B are correct explanations for the extracellular matrix.

Collagen fibers are long strands that connect the oblong structures that come off of proteins in a cell membrane. Collagen is a structural protein that provides strength and support to tissues in the body, including the cell membrane. These fibers help maintain the integrity and stability of the cell membrane by connecting the various structures within it. Fibronectin and proteoglycans are also important components of the extracellular matrix, but they do not specifically connect the oblong structures in the cell membrane. Therefore, the correct answer is collagen fibers.

Resolution refers to the ability to see small objects clearly and the smallest distance between two objects that can still be distinguished as separate. This means that resolution encompasses both the clarity of small objects and the ability to differentiate between closely spaced objects. Therefore, the correct answer is A and B.

As cells get bigger, their volume increases faster than their surface area. The surface area to volume ratio decreases, meaning that there is less membrane available to support the increased volume. This is why cells cannot continue to get bigger indefinitely.

The stroma is the inner, most important part of a chloroplast. It is a gel-like substance that surrounds the thylakoid membranes. The stroma is where important metabolic reactions, such as the Calvin cycle, take place. It contains enzymes, DNA, and ribosomes, which are necessary for the synthesis of carbohydrates and other organic molecules through photosynthesis. The thylakoid membranes, on the other hand, contain chlorophyll and other pigments that capture light energy and convert it into chemical energy. The stroma and thylakoid membranes work together to carry out the process of photosynthesis in plants.

Keratin is the protein of intermediate filaments. Intermediate filaments are a type of cytoskeletal protein that provide structural support to cells. Keratin is a fibrous protein that is found in the cytoplasm of epithelial cells, which make up the outer layer of the skin, hair, and nails. It forms a network of filaments that help maintain the shape and integrity of these tissues.

Microfilaments are solid filaments found in cells that are involved in various cellular processes, including muscle contraction. They are composed of actin proteins and provide structural support to the cell. In muscle cells, microfilaments play a crucial role in the sliding filament mechanism, where they interact with myosin to generate muscle contractions. Unlike microtubules, which are hollow and involved in cellular division and the movement of cilia and flagella, microfilaments are solid and primarily responsible for muscle contraction.

A scanning electron microscope (SEM) is used for thick sections because it provides a detailed and three-dimensional view of the sample's surface. Unlike transmission electron microscopes (TEM), which require thin sections, SEM can analyze thicker samples by scanning the surface with a focused beam of electrons. The electrons interact with the sample, producing signals that are used to create an image. This allows for a higher depth of field and the ability to study larger and bulkier specimens, making it the ideal choice for thick sections.

Dynein arms are the correct answer because they are responsible for the sliding movement of microtubules in cilia and flagella. These arms are composed of dynein proteins and are arranged in a radial pattern, forming half circles in the cross section. When dynein arms move, they cause the microtubules to slide against each other, resulting in the bending and waving motion of cilia and flagella.

Chromatin in the nucleus refers to the state of DNA when it is spread out and not dividing. During this phase, the DNA is in a relaxed and accessible form, allowing for gene expression and various cellular processes to occur. In contrast, when DNA is condensed, it is tightly packed and not actively being transcribed or replicated. The answer choice "DNA is spread out, not dividing" accurately describes the state of chromatin in the nucleus.

The nucleolus is responsible for making ribosomes. Ribosomes are cellular structures that are involved in protein synthesis. Inside the nucleolus, ribosomal RNA (rRNA) is synthesized and combined with proteins to form ribosomes. These ribosomes are then transported out of the nucleolus and into the cytoplasm, where they play a crucial role in protein production. Therefore, the nucleolus is primarily used for the production of ribosomes.