TISSUES AND CELLS Flashcards
In ____, ______ and ______ independently hypothesized that all plant and animal tissues are composed of cells.
1832 ; MATTHIAS JAKOB SCHLEIDEN (1804-1881) & THEODOR SCHWANN (1810 - 1882)
It is enclosed by small membranes and is eukaryotic, each with a distinct membrane-enclosed nucleus surrounded by a cytoplasm, fluid containing a system of membranous organelles, nonmembranous molecular assembles, and a cytoskeleton.
Animal Cells
The first zygotic cellular divisions produce cells called ______ which gives rise to all tissue types of the fetus.
blastomeres
Most cells of the fetus undergo a specialization process called
Cell differentiation.
What contains the plasma membrane that envelopes every eukaryotic cell?
it consists of phospholipids, cholesterol and proteins with oligosaccharide chains covalently linked to many of the phospholipids and proteins.
This membrane functions as a selective barrier regulating the passage of materials into and out of the cell and facilitates the transport of specific molecules.
Plasma membrane
What cells are specialized for movements?
Muscle and other contractile cells.
What cells are specialized for forming adhesive and tight junctions between cells?
Epithelial cells
What cells are specialized for synthesizing and secreting components of the extracellular matrix?
Fibroblasts, cells of bone and cartilage
What cells are specialized for converting physical and chemical stimuli into action potentials?
Neurons and sensory cells
What cells are specialized for the synthesis and secretions of degradative enzymes?
Cells of digestive glands
What cells are specialized for the synthesis and secretion of glycoproteins?
cells of mucous glands
What cells are specialized for the synthesis and secretions of steroids?
certain cells of the adrenal gland, testis and ovary
What cells are specialized for ion transport?
cells of the kidney and salivary gland ducts
What cells are specialized for intracellular digestion?
macrophages and neutrophils
What cells are specialized for lipid storage?
fat cells
What cells are specialized for metabolite absorption?
cells lining the intestine
What plasma membrane is linked to both the cytoskeleton and extracellular matrix components which allows a continuous exchange of influences?
Integrins
(T/F) Plasma Membrane ranges from 7.5 - 10 nm in thickness only visible in electron microscope.
True
A phospholipid is ________, with a phosphate group charge on the polar head and two long, nonpolar fatty acid chains which can be unsaturated and saturated.
Amphiphatic
It is a site where materials are exchanged between the all and its environment.
Plasma membrane
It transports small, nonpolar molecules directly through the lipid bilayer.
Diffusion
What are Channels?
a multipass proteins forming transmembrane pores through which ions or small molecules pass selectively.
What do you call water molecules which usually cross the plasma membrane through channel proteins?
Aquaporins
These are transmembrane proteins that bind small molecules and translocate them across the membrane via conformational changes.
Carriers
Diffusion, Channels, and Carrier proteins operate passively, allowing the movement of a substance across membranes down a concentration gradient due to ________ energy.
Kinetic Energy
These are macromolecules that normally enter cells enclosed within folds of plasma membrane in the process called
Endocytosis
This is the ingestion of particles such as bacteria or dead cell remnants.
Phagocytosis
Also known as “cell-eating”
Phagocytosis
This involves smaller invagination of the cell membrane which fuses and entrap extracellular fluid and its dissolved contents/
Pinocystosis
Also known as “Cell-drinking”
Pinocytosis
The fusion of membranous folds enclosed the bacterium in an intracellular vacuole which merges with a lysosome is called.
phagosome
What is transcytosis?
accomplished bulk transfer of dissolved substances across the cell.
This is a type of communicating junction which couples the cells and allows the exchange of ions and small molecules.
gap junctions
(T/F) Cells in multicellular organism communicate with each other to regulate tissue and organ development to control their growth and division and to coordinate their functions
True
What do cells use to detect and respond to various extracellular molecules and physical properties?
Receptors
What do you call the signal molecules in the endocrine signaling that carries blood from their sources to target cells throughout the body?
Hormones
What do you call the transport mechanism where the movement of substances down a concentration gradient due to kinetic energy; no expenditure of cellular energy is required; continues until equilibrium is reached?
Passive processes
What do you call the transport mechanism with unassisted movement of small, nonpolar substances down their concentration gradient across a selectively permeable membrane?
Simple Difussion
What do you call the transport mechanism where the movement of ions and small, polar molecules down their concentration gradient; assisted across a selectively permeable membrane by a transport proteins?
Facilitated Diffusion
Movement of ion down its concentration gradient through a protein-channel
Channel-mediated
Movement of small, polar molecules down its concentration gradient by a carrier protein
Carrier-mediated
Diffusion of water across a selectively permeable membrane
Osmosis
What do you call the transport mechanism where movement of substance requires expenditure of cellular energy?
Active Processes
Bulk movement of substance out of the cell by fusion of secretory vesicles with the plasma membrane
Exocytosis
Bulk movement of substances into the cell by vesicles forming at the plasma membrane
Endocytosis
Type of endocytosis which vesicles are formed as a particulate materials external to the cell are engulfed by pseudopodia.
Example: White blood cell engulfing a bacterium
Phagocytosis
Type of endocytosis in which vesicles are formed as interstitial fluid taken up by the cell.
Example: Formation of small vesicles in capillary wall to move substances
Pinocytosis
Type of endocytosis in which plasma membrane receptors first bind specific substances; receptor and bound substances then taken up by the cell.
Receptor-mediated endocytosis
Inside the cell membrane, the fluid cytoplasm (or cytosol) bathes metabolically active structures called________
Organelles
Determines the cell’s shape and motility
Cytoskeleton
What components are diffused through the cytoplasm, either freely or bound to proteins?
Oxygen, Carbon dioxide, electrolytic ions, low molecular weight substrates. metabolites and waste products.
These are macromolecule machines about 20 x 30 nm in size which assemble polypeptides from amino acids on molecules to transfer tRNA in a sequence specified by mRNA.
Ribosomes
What do you called the formed larger complexes during protein synthesis with same strand of mRNA?
Polyribosomes or polysomes
A convulated membranous network contained by most of the cells in the cytoplasm
Endoplasmic reticulum
A major site for vital cellular activites including biosynthesis of proteins and lipids.
Endoplasmic recticulum
It is prominent in cells specialized for protein secretion such as pancreatic acinar cells (making digestive enzymes), fibroblasts (collagen), and plasma cells (immunoglobulins) and proteins to be secreted by exocytosis.
Rough Endoplasmic Reticulum
It consists of saclike and parallel stacks of flattened “cisternae” each limited by membranes that are continuous with the outer membrane of the nuclear envelope.
Round endoplasmic reticulum.
It is made up of regions of RER that lack bound polyribosomes which is continuous with RER but less abundant.
Smooth Endoplasmic Reticulum
What type of cisternae does SER have?
More tubular or saclike with interconnected channels of various shapes and sizes rather than stacks of flattened cisternae.
Its enzymes perform synthesis of phospholipids and steroids, major constituents in cellular membranes.
Smooth Endoplasmic Reticulum.
(T/F) SER occupies a large portion of the cytoplasm.
True
Its enzymes allow the detoxification of potentially harmful exogenous molecules such as alcohol, barbiturates, and other harmful drugs.
Smooth endoplasmic reticulum
This reticulum is responsible for the sequestration and controlled release of Ca2+. This is particularly well developed in striated muscle cells, where the SER has an important role in the contraction process and assumes a specialized form.
Smooth endoplasmic reticulum
This dynamic organelle completes posttranslational modifications of proteins produced in the RER and then packages and addresses these proteins to their proper destinations.
Golgi Apparatus
Where does the small golgi complexes located?
near the nucleus
This is a small membrane-enclosed carriers where material moves from the RER cisternae to the golgi apparatus.
Transport Vesicles
These are sites of intracellular digestion and turnover of cellular components.
Lysosomes
An abundant cytoplasmic and nuclear protein complexes not associated with membrane in sizes of the small ribosomal subunit
Proteasomes
This protein complex functions to degrade denatured or nonfunctional polypeptides.
Proteasomes
They remove proteins no longer needed by the cell and provide an important mechanism for restricting the activity of a specific protein to a certain window of time.
Proteasomes
Deal primarily with free proteins as individual molecules.
Proteasomes
Digest organelles or membranes by autophagy
Lysosomes
This is a process in which the cells use lysosomes to dispose of excess or nonfunctioning organelles or membranes.
Autophagy
It is a membrane enclosed organelles with arrays of enzymes specialized for aerobic respiration and production of ATP.
Mitochondria
Mitochondria’s protein cytochrome activates proteases that degrade all cellular components in a regulated process called _________ which results in rapid cell death
apoptosis
These are spherical organelles enclosed by a single membrane and named for their enzymes producing and degrading hydrogen peroxide.
Peroxisomes
These spherical oragnelles contains enzymes for various metabollic reactions such as: for oxidation and detoxification and catalase that breaks down H2O.
Peroxisomes
What are the three types of polymers of cytoskeleton?
- Microtubules (25 nm in diameter)
- Actin Filaments or Microfilamments (5-7 nm)
- Intermediate Filaments (8-10 nm)
What separates the cytoplasm from the nucleoplasm?
Nuclear envelope
What penetrates the nuclear envelope with large assemblies of nucleoporins with eightfold symmetry through which proteins and protein–RNA complexes move in both directions.
Nuclear pore complex
It is the combination of DNA and its associated proteins.
Chromatin
The DNA molecule initially wraps around complexes of basic pro-
teins called
histones
A type of endoplasmic reticulum that lacks ribosomes, but includes enzymes for lipid and glycogen metabolism, for detoxification reactions, and for temporary Ca2+ sequestration
SER
Importance of Microtubules
maintaining cell shape and as tracks for transport of vesicles and organelles by the motor proteins kine- sin and dynein.
site of lipid synthesis and carbohydrate metabolism
SER
synthesizes proteins for secretion, incorporation into the plasma, membrane, and as enzymes within lysosomes
RER
Maintain cell’s shape and polarity; provide tracks for organelle and chromosome movement; move cilia and flagella
MICROTUBULES
Contract and move cells; change cell shape; cytokinesis; cytoplasmic transport and streaming
MICROFILAMENTS
Strengthen cell and tissue structure; maintain cell shape; maintain nuclear shape (lamins)
INTERMEDIATE FILAMETS
These are cytoplasmic structures or deposits filled with stored macromolecules and are not present in all cells.
Inclusions
Move substances (eg, mucus and dissolved materials) over the cell surface
Cilia
Long, singular membrane extension supported by microtubules; present on sperm cells
Flagellum
Numerous thin membrane folds projecting from the free cell surface; supported by microfilaments;
Increase membrane surface area for greater absorption
Microvili
Houses the DNA that serves as the genetic material for directing protein synthesis
Nucleus
Double membrane boundary between cytoplasm and nuclear contents; continuous with rough endoplasmic reticulum;
Separates nucleus from cytoplasm
Nuclear envelope
Openings through the nuclear envelope;
Allow passage of materials between the cytoplasm and nucleoplasm, including ribonucleic acid (RNA), protein, ions, and small water-soluble molecules
Nuclear Pores
Functions in synthesis of ribosomes
Nucleolus
Contents of cells between the plasma membrane and nuclear envelope; Responsible for many cellular processes
Cytoplasm
Viscous fluid medium with dissolved solutes (eg, ions, proteins, carbohydrates, lipids)
Cytosol
Extensive interconnected membrane network that varies in shape (eg, cisternae, tubules); ribosomes attached on cytoplasmic surface
RER
Extensive interconnected membrane network lacking ribosomes
SER
