4.5 The Cytoskeleton

• Geneticists can counsel pregnant women on available options.
• They can perform genetic research that leads to new drugs or foods.

• lysosomes are part of the endomembrane system, and they play a role in the digestion and organelle-recycling of animal cells.
• The lysosomes use their hydrolytic enzymes to destroy disease-causing organisms.
• A group of white blood cells called macrophages are part of your body's immune system.
• In a process called endocytosis, a section of the macrophage invaginates and kills a pathogen.
• The invaginated section with the pathogen inside becomes a vesicle.
• There is a lysosome in the vesicle.
• The pathogen is destroyed by the lysosome's hydrolytic enzymes.

• A macrophage has engulfed a potentially pathogenic bacterium and then fused with lysosomes to destroy it.
• For simplicity, we don't show the other organelles in the cell.

• Inside the cell, there would be ion and organic molecules, a network of protein fibers that help maintain the cell's shape, and the ability for cells within multicellular organisms to move.
• There are three types of fibers in the cytoskeleton.

• The cortex is around the cell's inner edge.
• They are like rubber bands.
• Microtubules in the cell's interior keep their shape by resisting forces.
• There are intermediate filaments in the cell.

• They function in cellular movement, have a diameter of about 7 nm, and are comprised of two strands of actin.

• Microfilaments actin filaments are also called for this reason.

• Microfilaments are two intertwined actin strands.

• Actin has a track for the movement of a motorProtein we call myosin.

• Actin can engage in cellular events that require motion, such as cell division in eukaryotic cells and cytoplasmic streaming, which is the cell cytoplasm's circular movement in plant cells.
• Actin and myosin can be found in muscle cells.
• Your muscles contract when actin and myosin slide past each other.

• Microfilaments give the cell rigidity and shape.
• They are able to depolymerize and reform quickly so that a cell can change its shape and movement.
• White blood cells are good at fighting infections.
• They can move to an area where they can kill the pathogen.

• You can see an example of a white blood cell in action by watching a short time-lapse video.
• It moves on to the other.

• There are several strands of fibers that are wound together.
• The diameter of the cytoskeleton elements is between those of microfilaments and microtubules.

• Their function is structural.
• They keep the cell's shape and anchor it in place.

• The most diverse group of elements are the intermediate filaments.
• There are several types of fibers.
• You are most likely aware of the strength of the hair, nails, and skin.

• Microtubules are hollow tubes.
• The microtubule's walls are composed of a-tubulin and b-tubulin.
• They help the cell resist compression, provide a track along which vesicles move through the cell, and pull replicated chromosomes to opposite ends of a dividing cell.
• Microtubules can disassemble and reform quickly.

• Microtubules are hollow.
• The tube's structure is shown in the left image.

• The centrosome's two parallel bodies are the structural elements of flagella, cilia, and centrioles.
• The microtubule-organizing center is found in animal cells.
• In prokaryotes, flagella and cilia are similar, but in eukaryotic cells they are different.

• There is only one flagellum or a few flagella in the cell.

• There is a ring of nine microtubule doublets surrounding a single microtubule doublet in the center of the flagellum.

• There are nine microtubule doublets surrounding a single microtubule doublet in this transmission electron micrograph of two flagella.

• You've completed a survey of prokaryotic and eukaryotic cell components.
• Table 4.1 contains a summary of cellular components.

• You already know that tissue is a group of cells.
• If cells are to work together, they need to communicate with each other just as they need to communicate with others.
• Cells communicate with each other.

• Animal cells are an example of cells in multicellular organisms releasing materials into the extracellular space.
• The most abundant component of these materials is collagen.
• There are proteoglycans interwoven with the Collagen fibers.

• The matrix is made up of a network of things.

• The cells have a surface called the extracellular surfaces.
• The molecule within the matrix changes the structure of the receptor.
• The microfilaments' structure is changed just inside the plasma membrane by the receptor.
• These changes in the structure of the cell cause chemical signals to reach the nucleus and turn on or off the transcription of specific DNA sections, thus changing the activities within the cell.

• An example of cell communication can be found in blood clotting.
• When a blood vessel is damaged, the cells in it display a tissue factor.
• When tissue factor binding with another factor in the extracellular matrix causes platelets to adhere to the damaged blood vessel's wall, it stimulates the adjacent smooth muscle cells in the blood vessel to contract, and causes a series of steps that stimulates the platelets to produce clotting.

• Direct contact or intercellular junctions can be used to communicate with each other.
• Plants and animals communicate in different ways.
• The junctions between plant and animal cells are called plasmodesmata.

• The cell wall that surrounds each cell separates them, so long stretches of the plasma membranes of neighboring plant cells can't touch one another.
• The xylem and phloem are used in such transport.
• Transport of materials from cell to cell, and thus throughout the plant, can be accomplished through numerous channels that pass between adjacent plant cells' cell walls.

• There is a channel between the cell walls.
• Materials can be passed from one plant cell to another.

• The cells are tightly held against each other by the claudins and occludins.

• There are tight junctions between animal cells.
• tight junction adherence is created by the presence of genes.

• This tight adherence prevents materials from leaking between the cells, and is found in most of the skin.
• The tight junctions of the cells in your bladder prevent urine from leaking.

• Cadherins connect to intermediate filaments to create desmosomes.

• A strong spot between cells is formed by a desmosome.
• It is created by linking the cadherins and intermediate filaments.

• A gap junction allows water and small molecule to pass between adjacent animal cells.

• A set of six connexins are arranged in a donut-like configuration in a gap junction.
• In cardiac muscle, gap junctions are important.
• The heart muscle cells can contract in tandem with the electrical signal for the muscle to contract.

• Vesicles and vacuoles are used for storage and transport.

• The smallest unit of life is a cell.
• vacuoles help break down macromolecules in most cells.

• Scientists use microscopes to study cells.
• Animal cells have a centrosome and lysosomes.
• The higher magnification, higher resolution, and more detail centrosome has two bodies to each other.
• The unified cell theory states that centrioles can be used in cell division.

• Animal cells have lysosomes.

• The plant cell wall protects the cell and gives it the shape it wants.
• All prokaryotes have a nucleus in their cells.
• The central vacuole has the ability to expand and produce more cytoplasm.

• Most have peptidoglycan cell walls.
• The diameter of prokaryotic cells is from 0.1 to 5.0mm.

• The nuclear envelope is included in the endomembrane system.
• The ER and Golgi apparatus will not have enough surface area if the cell grows too large.
• The increased volume requires these cellular components to work.

• There are Eukaryotic Cells that form the membranes.

• A eukaryotic cell has a cell structure similar to a prokaryotic cell.
• The SER is a prokaryotic cell with steroid hormones and a nucleus that is larger than a prokaryotic cell, has a true nucleus medications and poisons, and stores calcium ion.
• The Golgi apparatus is involved in sorting, as it surrounds its DNA, and has other tags, packaging, and distribution.
• Budding RER and Golgi functions.
• The lysosomes are created by the plasma membrane.
• The lysosomes digest the bilayer.
• The site of ribosome assembly is the nucleus's macromolecules.
• We find diseases.

• They perform a task.

• There are three different elements in the cytoskeleton.

• The microfilaments are the majority of the ATP produced in the cell.

• They are connected to each other via tight junctions and provide rigidity and shape to the cell.
• The plant cells are moving.

• When the cell resists compression, it serves as tracks for motor of an animal cell bind to a substance in the extracellular proteins that move vesicles through the cell, and pull matrix, a chain of reactions begins that changes activities replicated chromosomes to opposite ends of the cell.

• The structural element of centrioles, flagella, is between adjacent plant cells.

• Their connections between Cells and structures are different.

• While a desmosome acts like a spot weld, cellular activities seal between two adjacent cells.

• The basic unit of life is the _____.

• To get rid of waste, prokaryotes depend on materials.

bacteria that lack fimbriae are less likely

• The d. Golgi apparatus is destroyed due to a build up of sphingolipids.

• The environment and the environment relative to the cell are what humans use to move a cell.

• Cadherins and the steps involved in the creation of a __________ are the key components of desmosomes.

• Diseased animal cells can produce molecule that the reticulum can use to kill the cells in a controlled manner.

• The death molecule is passed through the Golgi.

• The death molecule is passed through the Golgi.

• Certain instruments are ideal for certain situations.

• There are at least two examples of this.

In what situation would a scanning electron answer be used?

• Antibiotics are used to fight infections in animals.
• The medicines kill prokaryotic cells.

coli have recently been shown to degrade blood cells In what other cells of the body do you have junctions?