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68 Cards in this Set
- Front
- Back
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What is a lipid raft? |
About 20% of the outer membrane surface contains lipid rafts, dynamic assemblies of saturated phospholipids (which pack tightly together) associated with unique lipids called sphingolipids and lots of cholesterol.
Assumed to be concentrating platforms for certain receptor molecules or for protein molecules needed for cell signaling, membrane invagination, or other functions. |
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What is the function of the mitochondria? |
Site of ATP synthesis, powerhouse of the cell |
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What is the function of the ribosomes? |
The site of protein synthesis |
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What is the function of the ROUGH endoplasmic reticulum (ER)? |
sugar groups are attached to proteins within the cisterns. Proteins are bound in vesicles for transport to the Golgi apparatus and other sites. External face synthesizes phospholipids |
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What is the function of the SMOOTH ER? |
Site of lipid and steroid (cholesterol) synthesis, lipid metabolism, and drug detoxification |
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What is the function of the golgi apparatus? |
Packages, modifies, and segregates proteins for secretion from the cell, inclusion of lysosomes, and incorporation into the plasma membrane |
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What is the function of the peroxisomes? |
The enzymes detoxify a number of toxic substances. The most important enzyme, catalase, breaks down hydrogen peroxide. |
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What is the function of lysosomes? |
Sites of intracellular digestion |
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What is the function of microtubules? |
Support the cell and give it shape. involved in intracellular and cellular movements. Form centriols and cilia and flagella, if present |
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What is the function of microfilaments? |
Involved in muscle contraction and other types of intracellular movement, help form the cells cytoskeleton |
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What is the function of intermediate filaments? |
The stable cytoskeletal elements, resist mechanical forces acting on the cell |
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What is the function of the centrioles |
As part of the centrosome, organize a microtubule network during mitosis (cell divisio) to form the spindle and asters. Form the bases of cilia and flagella. |
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What is the function of cilia? |
Coordinated movement creates unidirectional current that propels substances across cell surfaces |
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What is the function of flagellum? |
Propels the cell |
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What is the function of microvilli? |
Increase surface area for absorption |
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What is the function of the nucleus? |
Control center of the cell; responsible for transmitting genetic information and providing the instructions for protein synthesis |
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What is the function of the nuclear envelope? |
Separates the nucleoplasm form the cytoplasm and regulates passage of substances to and from the nucleus |
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What is the function of the nucleolus |
Site of ribosome subunit manufacture |
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What is the purpose of the chromatin? |
DNA constitutes the genes (active or inactive) |
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What is the function of the plasma membrane? |
Serves as the external cell barrier, and acts in transport of substances in and out of the cell. |
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What are the 3 basic parts of a human cell? |
Plasma Membrane (flexible outer boundary) Cytoplasm (intracellular fluid) Nucleus (control center) |
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The plasma membrane is made of a bimolecular layer of ________ and proteins that are a constantly changing “fluid mosaic.”
75% of which are ________________
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The plasma membrane is made of a bimolecular layer of ___lipids___ and proteins that are a constantly changing “fluid mosaic.”
75% are phospholipids
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A phospholipid is composed of what? |
A polar phosphate head (hydrophilic)
A nonpolar (hydrophobic) fatty acid tail. |
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What is the plasma membrane composed of?
75% ________________________ 5% _________________________ 20% _______________________ |
75% are phospholipids
5% are glycolipids (form the sugar coating which help cells identify each other)
20% are cholesterol (which increases stability and fluidity, as it allows leaks through the bilayer lipid membrane) |
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What are the 3 functions of integral proteins? |
1. Receptors
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**Name 5 functions of the peripheral proteins |
1. Help form part of glycocalyx = “sugar coating” on outer cell membrane
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What are CAMs and what are their function? |
Membrane proteins join cells through CAM’s, or __cell adhesion molecules__.
Acting as enzymes, membrane proteins can catalyze specific chemical reactions.
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Which membrane proteins facilitate cell-to-cell recognition? |
Glycoproteins |
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***What are the three types of membrane junctions, what are their major functions, and where are they typically found? |
Tight Junction – impermeable junctions, prevent molecules from passing through intercellular space (e.g. found in digestive tract) Desmosome – anchoring junctions bind adjacent cells together like a molecular “Velcro” and help from an internal tension-reducing network of fibers. (e.g. found in tissues subjected to great mechanical stress such as skin and heart muscle) 3. Gap junction – communicating junctions allow ions and small molecules to pass for intercellular communication. The transmembrane proteins form these pores, that allow small molecules to pass from cell to cell (e.g. found in electrically excitable tissues, such as the heart and smooth muscle) |
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What is the tight junction? What is its major fucntion, and where are they typically found? |
Tight Junction – impermeable junctions, prevent molecules from passing through intercellular space (e.g. found in digestive tract) |
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What is the desmosome? What is its major function, and where are they typically found? |
Desmosome – anchoring junctions bind adjacent cells together like a molecular “Velcro” and help from an internal tension-reducing network of fibers. (e.g. found in tissues subjected to great mechanical stress such as skin and heart muscle) |
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What is the gap junction? What is its major function? Where are they typically found? |
Gap junction – communicating junctions allow ions and small molecules to pass for intercellular communication. The transmembrane proteins form these pores, that allow small molecules to pass from cell to cell (e.g. found in electrically excitable tissues, such as the heart and smooth muscle) |
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Cell membranes (e.g. plasma membranes) are ____________ -permeable, which means that some substances can pass through the membrane, and some cannot. |
Cell membranes (e.g. plasma membranes) are __selectively__ -permeable, which means that some substances can pass through the membrane, and some cannot. |
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Osmosis is facilitated through channels in the cell membrane called _________________ |
Aquaporins (or AQPs) |
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**Osmolarity is the measure of total concentration of _______, and when solutions of a different osmolarity are separated by a membrane, __________ occurs until equilibrium of solute concentrations is reached. |
Osmolarity is the measure of total concentration of __solute__ particles, and when solutions of a different osmolarity are separated by a membrane, ___osmosis___ occurs until equilibrium of solute concentrations is reached. |
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If the membrane is selectively permeable, osmosis between solutions of different concentrations causes a change in __________ on both sides of the membrane. |
If the membrane is selectively permeable, osmosis between solutions of different concentrations causes a change in __concentration___ on both sides of the membrane. |
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Tonicity is the ability of a solution to cause a cell to shrink or burst. Which of these solutions will cause a cell to burst: Isotonic, hypotonic, or hypertonic? |
Hypotonic (hypo = below, tonic = tension), will cause a cell to take up water which would cause it to burst |
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Which of these three (hypotonic, hypertonic, isotonic) will cause a cell to shrink? |
Hypertonic (hyper = above, tonic = tension) will cause a cell to lose water, which would cause it to shrink.
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Which of these (hypertonic, hypotonic, isotonic) will not cause the cell volume to change? |
Isotonic (iso =same, tonic = tension) , no net movement of water in or out of cell, because there is the same tension. |
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What is the cytoplasm made up of what three things? |
Cytosol – water with solutes (protein, salts, sugars, etc.) Cytoplasmic organelles – (little organs – machines that perform tasks to keep cell alive) Inclusions – according to cell type: granules of glycogen (live and muscle), or pigments (skin&hair), lipid droplets (fat cells) vacuoles (crystals) |
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**What three cytoplasmic organelles have no membranes? |
1. Cytoskeleton 2. Centrioles 3. Ribosomes |
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_________ provide most of the cell’s ATP through a process called aerobic ______________. |
___Mitochondria__ provide most of the cell’s ATP through a process called aerobic __cell respiration_. |
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Cellular respiration is a collection of reactions in which _________ is broken down in the presence of ________to eventually make ATP. |
Cellular respiration is a collection of reactions in which __glucose__ is broken down in the presence of __oxygen___to eventually make ATP. |
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Mitochondira have double folded membranes called ________ |
Cristae! |
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What is the difference between free ribosomes and bound ribosomes, in terms of the proteins they produce |
Free ribosomes manufacture __soluble proteins that are used within the cell___.
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What types of proteins does the rough ER manufacture? |
Rough ER ribosomes manufacture ALL secreted proteins. Also synthesizes membrane proteins and phospholipids |
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**What are the 6 functions of proteins made by the smooth ER? |
1. In the liver - Lipid and Cholesterol synthesis 2. in liver cells especially - break down stored glycogen to from free glucose 3. in the liver AND kidneys - detoxification of drugs, pesticides, and carcinogens 4. synthesis of steroid-based hormones (e.g. testosterone in testes) 5. In the intestinal cells - absorption, synthesis, and transport of fats 6. in the skeletal and cardiac muscle - "sarcoplasmic reticulum" provides storage and release of calcium during muscle contraction |
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What are the 2 major functions of the golgi apparatus? |
Modifies, concentrates, and packages proteins and lipids into sacs called “vesicles” Acts as a traffic controller directing vesicles to their destinations (e.g. cytosol, organelles, cell membranes) |
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What 3 things can the vesicles created by the Golgi do? (i.e. 3 pathways) |
Pathway A - Vesicles containing proteins destined for export pinch off from the trans face as secretory vesicles, or granules, which migrate to the plasma membrane and discharge their contents form the cell by exocytosis. Specialized cells such as the enzyme producing cells of the pancreas have a prominent golgi apparatus Pathway B: The golgi apparatus pinches off other vesicles containing lipids and transmembrane proteins destine for plasma membrane Pathway C: The golgi apparatus also packages digestive enzymes into membranous lysosomes that remain in the cell. |
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What are the major functions of the lysosomes? |
Major functions of lysosomes are to digest ingested __bacteria, viruses, and toxins__ or ___degrade_____ non-functional organelles. |
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What can break down bone to release calcium or destroy injured or non-useful cells? |
Lysosomes |
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What are the 4 overall functions of the endomembrane system? |
Produce, store, and export biological molecules
AND
degrade potentially harmful substances |
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What are the 5 things that make up the endomembrane system?
HINT: includes everything but non-membrane organelles |
1. Nuclear Membrane |
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Which organelle neutralizes dangerous free radicals? |
peroxisomes! |
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What are the three types of rods that make up the cytoskeleton? |
Microtubules (largest) Microfilaments (smallest) Intermediate filaments |
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What are microfilaments made up of? |
flexible actin strands
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What are the intermediate fibers like? And what is their function? |
Intermediate fibers are tough ropelike fibers that form a network, which__strengthens____ the cell. |
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What are the microtubules made up of? Where do they radiate from? What is their function? |
Microtubules are hollow tubes made up of ___tubulin__, and most radiate from the __centrosome__.
Microtubules organize the cytoskeleton |
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What is the cell center, and where is it located? |
The cell center or __centrosome___ is distinguished by the presence of 2 centrioles (which are two small tubes formed by microtubules) _. Located in the cytoplasm |
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What are the main functions of the centrosome? |
Generates microtubules 2. Centrosome and centrioles organize the mitotic spindle during cell division. |
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What are 3 types of cellular extensions? And what are their functions? |
Cilia – move substances across cell surfaces Flagella – propel whole cells 3. Microvilli – increase surface area for absorption (e.g. in small intestine, microvilli help absorb nutrients) |
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The nucleus has a _________ with blueprints for creating nearly all the cellular proteins. |
The nucleus has a __genetic library_____ with blueprints for creating nearly all the cellular proteins. |
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Which cells are multinucleate? |
1. Some liver cells.
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What is the function of the nucleolus? |
Helps make ribosomal RNA which combines with proteins to make ribosomes. |
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**** What is a nucleosome? |
8 histones wrapped twice by DNA strand. |
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What is the chromatins function? |
Modification of histones activate or inactivate DNA for gene transcription (e.g. “turns on” the gene, or “turns off” the gene. |
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When the cell starts to divide, the chromatin condenses into _____________.
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When the cell starts to divide, the chromatin condenses into __chromosomes________.
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