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154 Cards in this Set

  • Front
  • Back
The __ is the basic structural and functional unit of life
Depends on individual and collective activity of cells
Activities of cells are dictated by subcellular structure- organelle
___ of life has a cellular basis
Separates intracellular fluids from extracellular fluids
Plasma membrane
Plays a dynamic role in cellular activity
Plasma membrane
____ is a glycoprotein area abutting the cell that provides highly specific biological markers by which cells recognize one another
Double bilayer of lipids with imbedded, dispersed proteins
Fluid Mosaic Model
Bilayer consists of phospholipids, cholesterol, and glycolipids.
Fluid Mosaic Model
____ are lipids with bound carbohydrate
_____ have hydrophobic and hydrophilic bipoles
Plasma Membrane Surfaces differ in the kind and amount of ___ they contain.
___ are found only in the outer membrane surface.
20% of all membrane lipid is ____
_____ are carbohydrate-attached lipids. Their role is to provide energy and also serve as markers for cellular recognition.
____ ____ make up 20% of the outer membrane surface
Lipid Rafts
___ ___ are composed of sphingolipids and cholesterol
Lipid Rafts
___ ___ are concentrating platforms for cell-signaling molecules for ex: for B-cell and T cell response when an antigen is incountered.
Lipid Rafts
Impermeable juntion that encircles the cell--the closely associeated areas of two cells whose membranes join together forming a virtual impermeable membrane
Tight Junction
Cell adhesion proteins anchoring junction scattered along the sides of cells; ___ function like rivets.
A nexus--a junction between certain animal cell types that allows different molecules and ions, mostly small intracellular signaling molecules to pass freely between cells.
Gap Junctions
- nonpolar and lipid-soluble substances
* Diffuse directly through the lipid bilayer
* Diffuse through channel proteins
Simple Diffusion
___ ___
* Transport of glucose, amino acids, and ions
* Transported substances bind carrier proteins or pass through protein channels.
Facilitated Diffusion
___ ____
* Are integral transmembrane proteins
* Show specificity for certain polar molecules including sugars and amino acids.
Carrier Proteins
____, occurs when the concentration of a solvent is different on opposite sides of a membrane.
Diffusion of water across a semipermeable membrane
Total concentration of solute particles in a solution
How a solution affects cell volume (watering plants)
The passage of water and solutes through a membrane by hydrostatice pressure.
Pressure gradient pushes solute-containing fluid from a higher-pressure area to a lower-pressure area
Solutions with the same solute concentration as that of the cytosol
Solution having greater solute concentration than that of the cytosol
Solutions having lesser solute concentration than that of the cytosol
Diffusion and Osmosis are both types of ____ _____ - that is, no energy is required for the molecules to move into or out of the cell.
Passive Transport
___ ___
* Uses ATP to move solutes across a membrane
*Requires carrier proteins
Active Transport
___ ___- When cells must move materials in an opposite direction--against a concentration gradient. It requires energy.
Active Transport
- two substances are moved across a membrane in the same direction.
Symport system
- two substances are moved across a membrane in opposite directions
Antiport System
- hydrolysis of ATP phosphorylates the transport protein causing conformational change.
Primary Active Transport
- use of an exchange pump (such as the Na+ -K pump) indirectly to drive the transport of other solutes.
Secondary Active Transport
Trnsport of large particles and macromolecules across plasma membranes.
Vesicular Trafficking
____ moves substance from the cell interior to the extracellular space.
_______ enables large particles and macromolecules to enter the cell.
______- moving substances into, across, and then out of a cell.
____ ____- moving substances from one area in the cell to another.
Vesicular trafficking
_____- pseudopods engulf solids and bring them into the cell's interior.
______ _______ ________-
the plasma membrane infolds, bringing extracellular fluid and solutes into the interior of the cell.
Fluid-phase endocytosis
_____ ______ _______-
Clathrin-coated pits provide the main route for endocytosis and transcytosis
Receptor-Mediated Endocytosis
___ ____ ____ _____-
caveolae that are platforms for a variety of signaling molecules
Non- clathrin-coated vesicles
Energy Source: Kinetic Energy
Ex: Movement of O2 through membrane
Simple Diffusion
Energy Source: Kinetic Energy
Ex: Movement of glucose into cells.
Facilitated Diffusion
Energy Source: Kinetic Energy
EX: Movement of H2O in & out of cells.
Energy Source: Hydrostatic Pressure
EX: Formation of Kidney filtrate
Energy Source: ATP
EX: Movement of ions across membranes
Active Transport of solutes
Energy Source: ATP
EX: Neurotransmitter secretion
Energy Source: ATP
EX: White Blood Cell Phagocytosis
Energy Source: ATP
EX: Absorption by intestinal cells
Fluid-phase endocytosis
Energy Source: ATP
EX: Hormone and cholesterol uptake.
Receptor-Mediated endocytosis
Voltage across a membrane
Membrane Potential
___ ____ ____- the point where K+ potential is balanced by the membrane potential.
Resting Membrane Potential
Ranges from -20 to -200 mV
Membrane Potential
___ ____- potential maintained by active transport of ions.
Steady State
____ ____ ____-
*Anchor cells to the extracellular matrix
*Assist in movement of cells past one another
*Rally protective white blood cells to injured or infected areas
*Regulate cell to cell interaction
Cell Adhesion Molecules (CAMs)
Important in normal development and immunity-growth
Contact Signaling
Voltage-regulated "ion gates" in nerve and muscle tissue.
Electrical Signaling
Neurotransmitters bind to chemically gated channel-linked receptors in nerve and muscle tissue.
Chemical Signaling
Ligands bind to a receptor which activates a G protein, causing the release of a second messenger, such as cyclic AMP.
G protein-linked receptors
Operation of a ___ ____,
* An extracellular ligand (first messenger), binds to a specific plasma membrane protein
* The receptor activates a __ ____ that relays the message to an effector protein.
Operation of a G Protein
Operation of a ___ _____,
The effector is an enzyme that produces a second messenger inside the cell.
*The second messenger activates a kinase
*The activated kinase can trigger a variety of cellular responses.
Operation of a G protein
____- material between plasma membrane and the nucleus- ___ is a collective term for the cytosol plus the organelles suspended w/in the cytosol.
___- largely water with dissolved protein, salts, sugars, and other solutes- ____ consists mostly of water, dissolved ions, small molecules (such as protein). It contains about 20% to 30% protein.
Metabolic machinery of the cell.
Cytoplasmic Organelles
Chemical substances such as glycosomes, glycogen granules, and pigment.
____ _____
*Specialized cellular compartments
Cytoplasmic Organelles
Mitochondria, peroxisomes, lysosomes, ER, and Golgi Apparatus.
Membranous Cytoplasmic Organelles
Cytoskeleton, centrioles, and ribosomes
Nonmembranous Cytoplasmic Organelles
*Double membrane structure with shelf-like cristae
______- provides most of the cell's ATP via aerobic cellular respiration.
______- contains its own DNA and RNA. Powerhouse of the cell.
____- Granules containing protein and rRNA
______- site of protein synthesis.
* free ___ synthesize souble proteins.
* Membrane-bound ribosomes synthesize proteins to be incorporated into membranes.
* Interconnected tubes and parallel membranes enclosing cisternae.
* Continuous with the nuclear membrane
Endoplasmic Reticulum
* External surface studded with ribosomes
Rough ER
* Manufactures all secreted proteins
* Responsible for the synthesis of integral membrane proteins and phospholipids for cell membranes.
Rough ER
* Tubules arranged in a looping network
* Catalyzes the following reactions in various organs of the body.
* In the liver- lipid and cholesterol metabolism breakdown of glycogen and, along with the kidneys, detoxification of drugs.
Smooth ER
* Catalyzes the following reactions in various orgons of the body
* In the intestinal cells - absorbtion, synthesis, and transport of fats
* In skeletal and cardiac muscle - storage and release of calcium.
Smooth ER
*Stacked and flattened membranous sacs
* Functions in modifications, concentration, and packaging of proteins.
* Transport vessels from the ER fuse with the cis face of the ____ ____
Golgi apparatus
* Transport vessels from the ER fuse with the cis face, proteins then pass through the ___ ___ to the trans face.
* Secretory vesicles leave the trans face of the ___ stack and move to designation of the cell.
Golgi Apparatus
* Spherical membranous bags containg digestive enzymes.
* Digest ingested bacteria, viruses, and toxins.
* Degrade nonfunctional organelles
* Breakdown glycogen and release thyroid hormone.
* Breakdown nonuseful tissue
* Breakdown bone to release Ca2+
* Secretory ____ are found in white blood cells, immune cells, and melanocytes
* System of organelles that function to:
* Produce, store, and export biological molecules
* Degrade potentially harmful substances
* Systems includes:
* Nuclear envelope, smooth and rough ER, lysosomes, vacuoles, transport vesicles, Golgi apparatus, and the plasma membrane.
Endomembrane System
* Membranous sacs containing oxidases and catalases
* Detoxify harmful or toxic substances
* Neutralize dangerous free radicals
____ ____- highly reactive chemicals with unpaired electrons
Free Radicals
* The skeleton of the cell
* Dynamic, elaborate series of rods running through the cytosol
* Consists of microtubules, microfilaments, and intermediate filaments
* Dynamic, hollow tubes made of the spherical protein tubulin
* Determine the overall shape of the cell and distribution of organelles
* Dynamic strands of the protein actin
* Attached to the cytoplamsic side of the plasma membrane
* Baces and strengthens the cell surface.
* Attach to CAMs and funtion in endocytosis and exocytosis.
* Tough, insoluable protein fibers with high tensile strength
* Resist pulling forces on the cell and help form desmosomes- a cell structure specialized for cell-to-cell adhesion
Intermediate Filaments
* Protein complexes that function in motility-cells "stagger" like humans as they carry their loads of vesicles or organelles through the cell.
* Powered by ATP
* Attach to receptors on organelles
Motor Molecules
* Small barrel-shaped organelles locaated in the centrosome near the nucleus
* Pinwheel array of nine triplets of microtubules
* Organize mitotic spindle during mitosis
* Form the bases of Cilia and Flagella
* Whip-like, mitile cellular extensions on exposed surfaces of certain cells
* Move substances in one direction across cell surfaces
* Contains nuclear envelope, nucleoli, chromatin, and distinct compartments rich in specific protein sets
Gene-containing control center of the cell
Contains the genteic library with blueprints for nearly all cellular proteins
Dictates the kinds and amounts of proteins to be sythesized
* Selectively permeable double membrane barrier containing pores
* Encloses jellylike nucleoplasm, which contains essential solutes-substances such as nucleotides (necessary for purposes such as the replication of DNA) and enzymes ( which direct activitieis that take place in the nucleus) are dissoved in the nucleoplasm.
Nuclear Envelope
* Outer membrane is continuous with the rough ER and is studded with ribosomes
* Inner membrane is lined with the nuclear lamina, which maintains the shape of the nucleus.
* Pore complex regulates transport of large molecules into and out of the nucleus.
Nuclear Envelope
* Dark-staining spherical bodies w/in the nucleus
* Site of ribosome prodution, RNA
* Threadlike strands of DNA and histones.
* Arrangd in fundamental units called nucleosomes
* Form condensed, barlike bodies of chromosomes when the nucleus starts to divide.
*Growth (G1)
Synthesis (S)
Growth (G2)
* Mitosis and Cytokinesis
Mitotic Phase
___ - metabolic activity and vigorous growth
___- cells that permanently cease dividing
DNA replication
S (synthetic)
____- preparation for division
* DNA helices begin unwinding from the nucleosomes
* Helicase untwists the double helix and exposes complemenary strands
* The site of replication is the replication bubble
* Each nucleotide strand serves as a template for building a new complementary strand.
DNA Replication
* The replisome uses RNA primers to begin DNA synthesis
* DNA polymerase III continues from the primer and covalently adds complementary nucleotides to the template.
DNA Replication
* Since DNA polymerase only works in one direction:
* A continuous leading strand is synthesized
* A discontiuous lagging strand is synthesized
* DNA ligase splices together the short segments of the discontinuous strand
* Two new telomeres are also synthesized
* This process is called simiconservative replication
DNA Replication
* Essential for body growth and tissue repair
Cell Division
Nuclear Division
Division of the Cytoplasm
The phases of Mitosis are:
* Prophase
* Metaphase
* Anaphase
* Telophase
* Cleavage furrow formed in late anaphase by contractile ring
Cytoplasm is pinched into two parts after mitisis ends
* Asters are seen as chromatin condenses into chromosomes
* Nucleoli disappear
* Centriole pairs separate and the mitotic spindle is formed
Early and Late Prophase
Chromosomes cluster at the middle of the cell with their centromeres aligned at the exact center, or equator, of the cell.
This arrangement of chromosomes along a plane midway beween the poles is called the ___ plate
* Centromeres of the chromosomes split
Motor proteins in kinetochores pull chromosomes toward the poles
* New sets of chromosomes extend into chromatin
* New nuclear membrane is formed from the rough ER
* Nucleoli reappear
* Generally ____ completes cell division.
Telophase and Cytokinesis
* Surface-to-surface-volume ratio of cells
* Chemical signals sucha as growth factors and hormones
* Contact Inhibition
* Cylins and cyclin-dependent kinases complexes
Control of Cell Division
* DNA serves as master blueprint for ___ ____
Protein Synthesis
___ are segments of DNA carrying instructions for a polypeptide chain.
____- of nucleotide bases form the genetic library
* Each triplet specifies coding for an ___ ___.
Amino Acid
_____- carries the genetic information from DNA in the nucleus to the ribosomes in the cytoplasm
Messenger RNA
____- Bound to amino acids base pair with the codons of mRNA at the ribosome to begin the process of protein synthesis.
Transfer RNA
____- A structural component of ribosomes
Ribosomal RNA
* Transfer of information from the sense strand of DNA to RNA
____ _____-
* Loosens histones from DNA in the area to be ____
* Binds to promoter, a DNA sequence specifying the start site of RNA synthesis
* Mediates the binding of RNA polymerase to promotor
Transcription factor
* An enzyme that oversees the synthesis of RNA
* Unwinds the DNA template
* Adds complementary ribonucleoside triphosphates on the DNA template
* Joins these RNA nucleotides together
* Encodes a termination signal to stop transcription
Transcription: RNA Polymerase
* A leader sequence on mRNA attaches to the small subunit of the ribosome
* Methionine-charged initiator tRNA binds to the small subunit
* The large ribosomal unit now binds to this complex forming a funtional ribosome
Initiation of Translation
___ codons code for amino acids according to the genetic code. (Triplet Code)
* DNA triplets are transcribed into mRNA codons by RNA polymerase
* Codons base pair with tRNA anitcodons at the ribosomes
* Amino acids are peptide bonded at the ribosomes to form polypeptide chains
* Start and stop codons are used in intitiating and ending translation
Information Transfer from DNA to RNA
____ ____- prevents protein-coding RNA from being translated
Antisense RNA
______- small RNAs that interfere with mRNAs made by certain exons.
______- mRNAs that act as swithces regulating protein synthesis in response to environmental conditions
Nonfunctional organelle proteins are degraded by ____.
Ubiquitin attaches to soluble proteins and they are degraded in _____.
Body fluids and cellular secretions
Extracellular Materials
The ____ ____ is the defining feature of connective tissue in animals
Extracellular Matrix
* All cells of the body contain the same DNA but develop into all the specialized cells of the body
* Cells in various parts of the embryo are exposed to different chemical signals that channel them into specific developmental pathways
Developmental Aspects of Cells
* Genes of specific cells are turned on or off (by methylation of their DNA)
* Cell specialization is determined by the kind of proteins that are made in that cell.
Developmental Aspects of Cells
* Development of specific and distinctive features in cells is called _____ _____
Cell differentiation
* Wear and tear theory attributes aging to little chemical insults and formation of free radicals that have cumulative effects throughout life.
* Genetic theory attributes aging to cessation of mitosis that is programmed into our genes.
Cell Aging