Biology 111 Chapter 6

Golgi Apparatus

flattened membrane sacs (cisternae); where products of the ER are modified, stored and sent to other destinations

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.

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

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

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.

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)

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.

Food Vacuole

a membranous sac formed by phagocytosis of microorganisms or particles to be used as food by the cell

Lysosome

a membranous sac of hydrolytic enzymes that many eukaryotic cells use to digest macromolecules; digest old organelles

Cytoskeleton

a network of microtubules, microfilaments, and intermediate filaments that extend throughout the cytoplasm and see a variety of mechanical, transport, and signaling functions

Phagocytosis

a process amoebas and many other unicellular eukaryotes use to eat by engulfing smaller organisms or food particles

Nucleolus

a prominent structure within the non-dividing nucleus;synthesizes ribosomal RNA; forms subunits of ribosomes

Cell Wall

a protective layer external to the plasma membrane in the cells of plants, prokaryotes, fungi, and some protists

Microfilament

actin; a cable composed of actin proteins in the cytoplasm of almost every eukaryotic cell, making up part of the cytoskeleton and acting alone or with myosin to cause cell contraction

Endoplasmic Reticulum (ER)

an extensive network of membranous tubules (cisternae) that accounts for more than half the total membrane in many eukaryotic cells; continuous with nuclear envelope

Chloroplast

an organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water; stroma- DNA

Peroxisome

breaks down fatty acids and detoxifies; an organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen producing and then degrading hydrogen peroxide

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

Gap Junction

communicating junction; a type of intercellular junction in animal cells, consisting of proteins surrounding a pore that allows the passage of materials between cells

Ribosome

contains rRNA and protein; performs protein synthesis; free and bound

Chromosome

discrete units made of organized DNA

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

Central Vacuole

mature plant cells; developed by coalescence of smaller vacuoles synthesized by ER and golgi apparatus

Vacuole

membrane bound sacs with varied functions; large vesicles derived from the endoplasmic reticulum and Golgi apparatus

Nucleus

organelle which is bounded by a double membrane; eukaryotic

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

Nuclear Envelope

porous; encloses the nucleus separating its contents from the cytoplasm; double membrane

Describe the basic structure of a plant cell wall

primary wall, middle lamella, secondary wall

Plastid

produces sugar through photosynthesis; one of a family of closely related organelles that includes chloroplasts, chromoplasts, and amyloplasts; found in photosynthetic eukaryotes

Contractile Vacuole

protists

Nucleoid

region that is not membrane-enclosed; prokaryotic

Cytoplasm

the contents of the cell bounded by the plasma membrane

Rough ER

the outer surface is studded with ribosomes and appears "rough"; protein synthesis; synthesizes phospholipids for own membrane and plasma membrane

Smooth ER

the outer surface lacks ribosomes giving it a "smooth" look; synthesizes lipids; releases glucose; stores calcium

Cytosol

the semifluid portion of the cytoplasm

Microtubule

tubulin; a hollow rod composed of tubulin proteins that makes up part of the cytoskeleton in all eukaryotic cells and is found in cilia and flagella

Transport Vesicle

where secretory proteins are packaged; vesicles in transit to endomembrane system or plasma membrane

Prokaryotic Cell

"before nucleus"; the DNA is concentrated in a nulceoid; no membrane bound organelles

Eukaryotic Cell

"true nucleus"; most of the DNA is in the nucleus; membrane bound organelles

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.

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.

Compare the structure of smooth and rough ER.

Rough ER has an outer surface studded with ribosomes, the smooth ER lacks ribosomes

Tight Junction

a type of intercellular junction between animal cells that prevents the leakage of material through the space between cells

Mitochondria

an organelle in eukaryotic cells that serve as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP

Desmosome

anchoring junction; a type of intercellular junction in animal cells that function as a rivet, fastening cells together