Biology 111 chapter 6
Briefly explain how the nucleus controls protein synthesis in the cytoplasm.
The nucleus directs protein synthesis by synthesizing messenger RNA (mRNA) according to instructions provided by the DNA. The mRNA is then transported to the cytoplasm via the nuclear pores. Once an mRNA molecule reaches the cytoplasm, ribosomes translate the mRNA's genetic message into the primary structure of a specific polypeptide.
Explain the roles of peroxisomes in eukaryotic cells.
breaks down fatty acids for energy or detoxifying alcohol and other poisons; Oxidation Peroxisomes are specialized metabolic compartments bounded by a single membrane Peroxisomes produce hydrogen peroxide and convert it to water Oxygen is used to break down different types of molecules
Describe the endosymbiont theory for the evolutionary origin of mitochondria and chloroplasts, including the evidence that supports this theory.
early ancestor of eukaryotic cells engulfed an oxygen-using non photosynthetic prokaryotic cell. Eventually the engulfed cell formed a relationship with the host cell in which it was enclosed, becoming endosymbiont. -Mitochondria have their own cell membranes, just like a prokaryotic cell does. -DNA - Each mitochondrion has its own circular DNA genome, like a bacteria's genome, but much smaller. This DNA is passed from a mitochondrion to its offspring and is separate from the "host" cell's genome in the nucleus. -Reproduction — Mitochondria multiply by pinching in half — the same process used by bacteria. Every new mitochondrion must be produced from a parent mitochondrion in this way; if a cell's mitochondria are removed, it can't build new ones from scratch.
Compare the structure, monomers, and functions of microtubules, microfilaments, and intermediate filaments.
hollow tubes of protein about 25 nanometers in diameter, support the cell and moves organelles within the cell; Long, thin fibers that function in the movement and support of the cell; range from 7-11nm in diameter, and strengthen the cell and help maintain its shape, stabilize the positions of organelles, and stabilize the position of the cell with respect to surrounding cells through specialized attachment to the cell membrane
Describe three examples of intracellular digestion by lysosomes.
phagocytosis (ingestion of other dying cells or larger extracellular material, like foreign invading microbes) endocytosis (where receptor proteins are recycled from the cell surface) autophagy (where in old or unneeded organelles or proteins, or microbes that have invaded the cytoplasm are delivered to the lysosome
Describe the basic structure of a plant cell wall
primary wall, middle lamella, secondary wall
Describe the structure and roles of the extracellular matrix in animal cells.
Animals cells secrete ECM which is composed mostly of glycoproteins and other carbohydrate-containing moleculues. It function in animal cells are for support, adhesion, movement and regulation.
Describe the structure of a mitochondrion and explain the importance of compartmentalization in mitochondrial function.
Bound by a double membrane (smooth outer, folded inner, space between is called cristae) and proteins made by free ribosome's and ribosome's within it Contains its own unique, maternally inherited DNA that controls the synthesis of the proteins in its membrane Compartmentalization provides a large surface area that enhances the productivity of the mitochondrion, cellular respiration/ ATP/ energy production and provides a unique internal environment for reactions
Identify the three functional compartments of a chloroplast. Explain the importance of compartmentalization in chloroplast function.
Bound by a double membrane and proteins, made by free ribosome's and ribosome's within it Contains its own unique circularDNA that controls the synthesis of the proteins in the membrane Contains thylakoids (flattened structures of space and membrane), grana (stacks of flattened structures), and stroma (fluid, where DNA is located) Contains green pigment and enzymes that allow for photosynthesis Compartmentalization provides chloroplasts with more surface area for the enzymes to instigate the reactions required for conversion of light energy to chemical energy, photosynthesis.
Distinguish between free and bound ribosomes in terms of location and function.
Free ribosomes are used within the cytosol and create protein which functions within the cytosol. Bound ribosomes, attached to the endoplasmic reticulum or nuclear envelope, usually make proteins that will be included within membranes, packaged into organelles, or exported from the cell.
Endomembrane system describe the structure and function of each component
Functions of Smooth ER- Synthesizes lipids Metabolizes carbohydrates Detoxifies poison Stores calcium Functions of Rough ER- Has bound ribosomes, which secrete glycoproteins (proteins covalently bonded to carbohydrates) Distributes transport vesicles, proteins surrounded by membranes Is a membrane factory for the cell; lysosomes are digestive vacuoles; Functions of the Golgi apparatus: Modifies products of the ER Manufactures certain macromolecules Sorts and packages materials into transport vesicles The Golgi Apparatus: Shipping and Receiving Center
Explain the role of the nucleolus in protein synthesis.
It synthesizes ribosomal RNA (rRNA) and combines it with protein to assemble ribosomal sub-units to pass which then passes through the Nuclear pores to the cytoplasm.
Briefly describe the energy conversions carried out by mitochondria and chloroplasts.
MITOCHONDRIA = CELLULAR RESPIRATION = GENERATE ATP BY EXTRACTING ENERGY FROM SUGARS, FATS, AND OTHER FUELS WITH THE HELP OF OXYGEN. CHLOROPLASTS = PHOTOSYNTHESIS = CONVERT SOLAR ENERGY TO CHEMICAL ENERGY AND SYNTHESIZE NEW ORGANIC COMPOUNDS SUCH AS SUGAR FROM CO2 AND H2O.
Describe the structure and function of the nuclear envelope, including the role of the pore complex.
Nuclear envelope -> Double membrane enclosing the nucleus, perforated by pores. The nuclear envelope is a double membrane. The envelope is perforated by pores that are about 100 nm apart. At the lip of each pore, the inner and outer membrane of the nuclear envelope are fused. The nuclear envelope encloses the nucleus separating its contents from the cytoplasm
Distinguish between prokaryotic and eukaryotic cells.
Prokaryotic- do not contain a nucleus or any other membrane-bound organelle. Eukaryotic- contain membrane-bound organelles, including a nucleus
Compare the structure of smooth and rough ER.
Rough ER has an outer surface studded with ribosomes, the smooth ER lacks ribosomes
Describe the functions of the cytoskeleton.
The cytoskeleton helps to maintain cell shape. But the primary importance of the cytoskeleton is in cell motility. The internal movement of cell organelles, as well as cell locomotion and muscle fiber contraction could not take place without the cytoskeleton. The cytoskeleton is an organized network of three primary protein filaments: microtubules, actin filaments, and intermediate fibers.
Explain how the extracellular matrix may act to integrate changes inside and outside the cell.
The ecm is made up of a network of proteoglycans; they attach to glycoproteins like fibronectin which attaches to cell proteins called integrins which integrates information from both outside and inside the cell
List the components of the endomembrane system, and briefly describe the structure and function of each component.
The endomembrane system regulates protein traffic and performs metabolic functions in the cell Components of the endomembrane system : Nuclear envelope Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Plasma membrane (These components are either continuous or connected via transfer by vesicles)
