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DR-A&PCh3

Dragon Rises Anatomy and Physiology Chapter 3

term or phrasecompletion
cell simplest structural and functional unit of life
all organisms are composed... of cells
an organism's structure and functions... are due to the activities of its cells
the activities of cells drive... the workings of the human body
the activities of cells underlie... the mechanisms of disease
the activities of cells determine... the rationale of therapy
cells come from... only pre-existing cells, not from non-living matter
cells of all species... have many fundamental similarities in their chemical composition and metabolic mechanisms
cytology scientific study of cells
there are ____ (number) types of cells in the human body about 200
squamous cells thin and flat with nucleus creating a bulge - ex: epidermis, esophagus
cuboidal cells squarish, about as tall as wide - ex: liver cells
columnar cells taller than wide - ex: stomach and intestine epithelium
polygonal cells irregularly angular shapes with four or more sides - ex: squamous, cuboidal, and columnar cells when examined from above
stellate cells starlike shape - ex: cell body of nerve cells
spheroid to ovoid cells round to oval - ex: egg cell, WBC
discoid cells disc-shaped - ex: RBC
fusiform cells thick in middle, tapered toward ends - ex: smooth muscle
fibrous cells threadlike shape - ex: skeletal muscle, axons
the size of most human cells 10-15 micrometers in diameter
oocyte egg cells - largest cell, 100 micrometers in diameter, barely visible to the naked eye
sperm cell a head of 5 micrometers by 3 micrometers and a tail of 50 micrometers long. granule cell of cerebellum is typically 4-4.5 micrometers long
nerve cell can be 1 meter long. an axon can be as long as 6 feet. longest human cell, but too slender to be seen with the naked eye.
feature of cells: cells possess... a genetic program and the means to use it
feature of cells: cells can... replicate
feature of cells: cells acquire and utilize... energy
feature of cells: cells carry out... a variety of chemical reactions
feature of cells: cells respond... to stimuli
feature of cells: cells can... self-regulate
substances that make up the cell. percentage of water: 75-80%
substances that make up the cell. percentage of proteins: 10-20%
substances that make up the cell. percentage of lipids: 2%
substances that make up the cell. percentage of carbohydrates: 1%
substances that make up the cell. (1-5) water, proteins, lipids, carbohydrates, electrolytes
in lean adults, body fluids constitute (percentage, male and female) 55% of female and 60% of male total body mass
ICF intracellular fluids (2/3 of body fluids)
ECF extracellular fluids (1/3 of body fluids) - body's internal environment
two major subdivisions of ECF interstitial fluid, intravascular fluid
interstitial fluid fluid that fills the spaces between most cells of the body. about 80% of ECF, 15% of body weight
examples of interstitial fluids lymph, cerebrospinal fluid, synovial fluid, aqueous humor and vitrous body (eyes)
lymph ECF within lymphatic vessels
cerebrospinal fluid ECF in and around brain and spinal cord
synovial fluid ECF of joints
aqueous humor and vitrous body ECF of eyes
intravascular fluid ECF within blood vessels -- plasma (WBC, RBC and platelets are in this fluid. About 20% of ECF, 5% of body weight)
two fundamentally different types of cells prokaryotic (eg. bacteria), eukaryotic (eg. animals, plants, fungi)
prokaryotes means before 'nucleus'
eukaryotes eu - true; karyon - nucleus. these cells possess a nucleus
eukaryotic cells consist of... plasma (cell) membrane, cytoplasm, nucleus
plasma (cell) membrane surrounds cell, defines boundaries; composition and function can vary from one region of the cell to another
surface extensions of plasma (cell) membrane cilia, flagella, microvilli
cytoplasm cytosol (contains ICF), organelles, cytoskeleton
unit membrane forms the border of the cell and many of its organelles - appears as a pair of dark parallel lines around the cell under an electron microscope
plasma membrane unit membrane at cell surface
functions of the plasma membrane: defines... cell boundaries
functions of the plasma membrane: governs... interactions with other cells
functions of the plasma membrane: controls... passage of materials in and out of cell
intracellular face of plasma membrane side that faces the cytoplasm
extracellular face of plasma membrane side that faces outward
the plasma membrane is... an oily film of lipids with diverse proteins embedded
percentage of molecules in plasma membrane that are lipids 98%
percentage of plasma membrane lipids that are phospholipids 75%
phospholipids in the plasma membrane are... amphiphilic / amphipatic molecules arranged in a bilayer
phospholipids in the plasma membrane have hydrophilic phosphate heads that... face the fluid on each side of the membrane
phospholipids in the plasma membrane have hydrophobic tails that... are directed toward the center, avoiding fluid
in the plasma membrane, phospholipids drift... laterally from place to place
the drifting laterally of phospholipids in the plasma membrane... helps keep the membrane fluid
20% of the membrane lipids made up of cholesterol
this holds phospholipids still and can stiffen the membrane cholesterol
5% of the membrane lipids glycolipids
glycolipids are... phospholipids with short carbohydrate chains on the extracellular face
glycolipids contribute to... glycocalyx
glycocalyx carbohydrate coating on the cell surface
in the plasma membrane, proteins make up... 2% of the molecules
in the plasma membrane, proteins make up... 50% of the weight
types of membrane proteins transmembrane proteins, peripheral proteins
proteins that pass through the membrane transmembrane proteins
proteins that have a hydrophilic region in contact with the cytoplasm and extracellular fluid transmembrane proteins
proteins that have hydrophobic regions that pass back and forth through the lipid of the membrane transmembrane proteins
most transmembrane proteins are... glycoproteins
transmembrane proteins can drift... freely about in the phospholipid film
some transmembrane proteins are anchored... to the cytoskeleton
peripheral proteins adhere... to one face of the membrane
these proteins are usually tethered to the cytoskeleton peripheral proteins
functions of membrane proteins include... receptors, second-messenger systems, enzymes, ion channels, carriers, cell-identity markers, cell-adhesion molecules
membrane protein - receptor binds to chemical messengers such as hormones sent by other cells
membrane protein - enzyme breaks down chemical messenger and terminates its effect
membrane protein - ion channel constantly open and allows ions to pas into and out of the cell
membrane protein - gated ion channel opens and closes to allow ions through only at certain times
membrane protein - cell identity marker glycoprotein distinguishing the body's own cells from foreign cells
membrane protein - cell adhesion molecule binds one cell to another
membrane proteins allow cell communication... via chemical signals
on the surface of plasma membrane target cell receptors
bind hormones and neurotransmitters receptor proteins
cell membrane protein receptors... are usually specific for one substrate
in a second-messenger system... a messenger chemical binds to a surface receptor, which triggers changes within the cell that produce a second messenger in the cytoplasm
second messenger systems... involve transmembrane proteins and peripheral proteins
enzymes in a plasma membrane... carry out final stages of starch and protein digestion in small intestine
membrane proteins help produce... second messenger systems (cAMP)
membrane proteins break down... old chemical messengers, stops excessive stimulation
transmembrane proteins with pores... allow water and dissolved ions to pass through membrane
some transmembrane proteins are... constantly open, others are gated channels that open and close in response to stimuli
examples of transmembrane protein gated channels ligand (chemically)-regulated gates), voltage-regulated gates, mechanically regulated gates (stretch and pressure)
transmembrane proteins with pores play an important role in... the timing of nerve signals and muscle contraction
channelopathies family of diseases that result from defects in channel proteins
carriers or pumps (wrt transmembrane proteins) transmembrane proteins bind to glucose, electrolytes, and other solutes, transfer them across the membrane; pumps consume ATP in the process
cell-identity markers enable our bodies to identify which cells belong to it and which are foreign invaders
cell-identity markers are made up of... glycoproteins that contribute to the glycocalyx - carbohydrate surface coating - acts like a cell's "identification tag"
cell adhesion molecules (CAMs)... adhere cells to each other and to extracellular material
cell adhesion molecules are necessary because... cells do not grow or survive normally unless they are mechanically linked to the extracellular material
cell adhesion molecules - particular events sperm-egg binding; binding of immune cell to a cancer cell requires CAMs
glycocalyx unique fuzzy coat external to the plasma membrane
the glycocalyx is unique... in everyone but identical twins
the glycocalyx is made up of... carbohydrate moieties of membrane glycoproteins and glycolipids
functions of the glycocalyx protection; immunity to infection; defense against cancer; transplant compatibility; cell adhesion; fertilization; embryonic development
microvilli extensions of the membrane, serving to increase the cell's surface area
microvilli are best developed in cells specialized in... absorption
microvilli give ____ (number to number) times more absorptive surface area 15 to 40
on some cells, microvilli are very dense and appear as a fringe, known as the... brush border
actin filaments have this effect on microvilli they shorten it, pushing absorbed contents down into the cell
cilia plasma membrane structure, hairlike processes about 7-10 um long
found on nearly every cell (WRT cilia) a single, nonmotile primary cilium. acts as the antenna for monitoring nearby conditions. plays sensory role in inner ear, retina, nasal cavity, and kidney
motile cilia are found... in respiratory tract, uterine tubes, ventricles of the brain, efferent ductules of testes
the pattern of motile cilia movement beat in waves; sweep substances across surface in same direction; have power strokes followed by recovery strokes
the saline layer at the cell surface is due to these... chloride pumps which move Cl- out of the cell. Na+ and H2O molecules follow
cystic fibrosis hereditary disease in which cells make chloride pumps but fail to install them in the plasma membrane. this means that these chloride pumps fail to create an adequate saline layer on the cell surface.
the effects of cystic fibrosis thick mucus plugs pancreatic ducts and respiratory tracts; inadequate digestion of nutrients and absorption of oxygen; chronic respiratory infections; life expectancy of 30
the only functional flagellum the tail of sperm
a flagella is... a whiplike structure identical to cilium; much longer than cilium; stiffened by coarse fibers that support the tail
the movement of flagella undulating, snakelike - no power stroke or recovery stroke as in cillia
plasma membrane a barrier and a gateway between the cytoplasm and ECF
plasma membrane is ____ permeable selectively; allows some things through, and prevents other things from entering and leaving the cell
passive transport mechanisms... require no ATP; the random molecular motion of particles provides the necessary energy
examples of passive transport mechanisms filtration, diffusion, osmosis
active transport mechanisms consumes ATP; active transport and vesicular trnasport
carrier-mediated mechanisms... use a membrane protein to transport substances from one side of the membrane to the other; active transport and facilitated diffusion
filtration process in which particles are driven through a selectively permeable membrane by hydrostatic pressure
hydrostatic pressure force exerted on a membrane by water
examples of filtration filtration of nutrients through gaps in blood capillary walls into tissue fluids; filtration of wastes from the blood in the kidneys while holding back blood cells and proteins
simple diffusion... needs only concentration gradient
simple diffusion the net movement of particles from area of high concentration to area of low concentration (moves down the concentration gradient), due to their constant, spontaneous motion
factors affecting diffusion rate through a membrane temperature (+ temp, + motion of particles); molecular weight (larger molecules move more slowly); steepness of concentrated gradient (+ difference, + rate of diffusion); membrane surface area (+ area, + rate); membrane permeability (+ permeable, +rate)
example of simple diffusion oxygen or water diffusing into a cell and CO2 diffusing out
osmosis flow of water/solvent through a semi-permeable membrane from an area of higher water concentration (lower solute conc) to one of lower water conc (higher solute conc), therefor UP a solute conc gradient
aquaporins channel proteins in plasma membrane specialized for passage of water
cells can increase rate of osmosis by... installing more aquaporins
cells can decrease rate of osmosis by... removing aquaporins
phospholipid regions of the plasma membrane are hydrophobic, however... significant amounts of water diffuse through the membrane
one osmole = 1 mole of dissolved particles
osmolarity the number of osmoles of solution per liter of solution
osmotic pressure amount of hydrostatic pressure required to stop osmosis
reverse osmosis pressure applied to one side, overrides pressure, drives against concentration gradient
an example of reverse osmosis in the cardiovascular system the heart drives water out of the capillaries by reverse osmosis - capillary filtration
tonicity ability of a solution to affect fluid volume and pressure in a cell by changing its water content
isotonic solution solute concentration same on both sides of the membrane. most cells in the body are in isotonic solution. causes no change in cell volume or shape.
hypotonic solution less solute (more water). cells absorb water and rupture (lyse)
hypertonic solution high solute concentration (less water), cells lose water and shrivel (crenate)
carrier mediated transport transport proteins in the plasma membrane that carry solutes from one side of the membrane to another
carrier-mediated transports have specificity, meaning: they are specific for a certain ligand. solutes bind to a specific receptor site on carrier protein
carrier proteins, unlike enzymes... do not chemically change their ligand; carriers simply pick ligands up on one side of the membrane and release them, unchanged, on the other
carrier-mediated transports recognize saturation, meaning: as the solute concentration rises, the rate of transport rises, but only to a point - transport maximum (Tm)
types of carrier-mediated transport proteins uniport, symport, antiport
carrier-mediated transport, uniport: carries only one solute at a time
carrier-mediated transport, symport: carries two ore more solutes simultaneously in the same direction (cotransport)
carrier-mediated transport, antiport: carries two or more solutes in opposite directions (counter-transport) - example: sodium-potassium pump brings in K+ and removes Na+ from cell
two types of carrier-mediated transport facilitated diffusion and active transport
facilitated diffusion carrier mediated transport of solute through a membrane down its concentration gradient
facilitated diffusion requires... both a concentration gradient and a protein channel
facilitated diffusion differs from active transport because... facilitated diffusion does not consume ATP
in facilitated diffusion, a solute attaches to a binding site on carrier, and then... the carrier changes conformation, and releases the solute on the other side of the membrane
big hydrophilic substances need protein channels for diffusion through hydrophobic parts of the plasma membrane because... of their size and electrical charge
example of facilitated diffusion glucose or amino acids moving from blood into a cell
passive transport... equalizes concentrations of substances on both sides of the plasma membrane
when cells need to maintain a greater concentration of a given substance on one side of its membrane, it uses... active transport
active transport depends on... concentration gradient, electric gradient, membrane potential, electrochemical gradient
examples of active transport pumping of glucose into cells that line the small intestines; sodium-potassium pump for ICF/ECF
in active transport, molecules move through a transport protein, but now... energy must be expended to move them against their concentration gradient (using ATP)
active transport involves... the transport of solute through a membrane up (against) its concentration gradient
active transport makes use of... ATP energy - consumed to change carrier
examples of active transport sodium-potassium pump keeps K+ concentration higher inside the cell; bringing amino acids into cell; pumping Ca2+ out of the cell
during maintenance of membrane potential in a cell... each pump cycle consumes one ATP and exchanges three Na+ for two K+
during maintenance of membrane potential in a cell... keeps the K+ concentration higher and the Na+ concentration lower within the cell than in ECF
during maintenance of membrane potential in a cell... pump keeps inside more negative, outside more positive
maintenance of membrane potential in a cell is... necessary for nerve and muscle function
thyroid hormone increases the number of... Na+-K+ pumps
as a byproduct of the consumption of ATP, active transport... produces heat
vesicular transport processes that move large particles, fluid droplets, or numerous molecules at once through the membrane in vesicles (bubble-like enclosures of membrane)
endocytosis vesicular processes that bring material into the cell
three types of endocytosis phagocytosis, pinocytosis, receptor-mediated endocytosis
phagocytosis cell-eating, engulfing large particles - pseudopods, phagosomes, macrophages
pinocytosis cell drinking, taking in droplets of ECF containing molecules useful in the cell. occurs in all human cells. "bulk phase" endocytosis. involves "pinocytic vesicles"
receptor-mediated endocytosis selective endocytosis. particles bind to specific receptors on plasma membrane; clathrin-coated vesicle; update of LDL, HIV virus, insulin from bloodstream to cell
exocytosis discharging material from the cell - utilizes motor proteins energized by ATP
phagocytosis keeps tissues free of... debris and infectious microorganisms
the first step in the process of receptor-mediated endocytosis extracellular molecules bind to receptors on the plasma membrane; receptors cluster together
the second step in the process of receptor-mediated endocytosis plasma membrane sinks inward, forms clathrin-coated pit
the third step in the process of receptor-mediated endocytosis pit separates from plasma membrane, forms clathrin-coated vesicle containing concentrated molecules from ECF
importance of exocytosis secretory cell liberating hormones, enzymes, etc, neurotransmitters released by nerve cells
first step of exocytosis secretory vesicle approaches the plasma membrane and docks on it by means of linking-proteins. the plasma membrane caves in at that point to meet the vescile
second step of exocytosis plasma membrane and vesicle unite to form a fusion pore through which the vesicle contents are released
cell interior contains... nucleus and cytoplasm
cytoplasm is located... inside the plasma membrane but outside the nucleus
most cellular activities take place... in the cytoplasm
the cytoplasm consists of... structures (organelles, cytoskeleton, inclusions) and cytosol (gelatinous substance containing structures)
this is the largest organelle the nucleus - 5 um in diameter
often centrally located within the cell nucleus
contains DNA nucleus
these cells contain no nuclues red blood cells - incapable of division
these cells are multinucleated skeletal muscle cells - cells fuse during development so many cells appear as one cell, allowing for a faster rate of AP conduction
nuclear envelope two unite membrane; encloses DNA
nuclear envelope pores allows RNA but not DNA through
chromatin DNA wrapped around associated proteins when cell is not dividing (i.e. during interphase)
chromosomes chromatin folds up to form chromosomes when cell is dividing.
nucleoplasm material in nucleus - chromatin, threadlike matter composed of DNA and protein
nucleolus one or more dark masses - site of ribosomes production; ribosomes move out of nucleus to RER
cytoskeleton a collection of filaments and cylinders
the cytoskeleton determines... the shape of cell, lends structural support, organizes its contents, directs movements of substances through the cell, and contributes to the movements of the cell as a whole
the cytoskeleton is composed of... microfilaments, intermediate fibers, microtubules
microfilament 6nm thick, actin, mainly in cell periphery; forms terminal web; for movement and support
intermediate fibers 8-10nm, support, strength, structure; stabilize organelles, help attachments between cells
microtubules 25nm, tubulin, movement; support, maintain cell shape and rigidity, not permanent structures
endoplasmic reticulum system of interconnected channels called cisternae enclosed by unit membrane
rough endoplasmic reticulum composed of parallel, flattened sacs covered with ribosomes
rough endoplasmic reticulum is continuous... with outer membrane of nuclear envolope
rough endoplasmic reticulum produces... the phospholipids and proteins of the plasma membrane
rough endoplasmic reticulum synthesizes... proteins that are packaged in other organelles or secreted from cell
smooth endoplasmic reticulum lack... ribosomes
smooth endoplasmic reticulum has cisternae thought to be... continuous with those of the rough ER
smooth endoplasmic reticulum synthesizes... steroids and other lipids
smooth endoplasmic reticulum inactivates and detoxifies... alcohol and other drugs
smooth endoplasmic reticulum manufactures... all membranes of the cell
smooth endoplasmic reticulum stores and releases... Ca ions in muscle cells
rough and smooth endoplasmic reticulum are functionally... different parts of the same network
organelles are... structures internal to the cell which carry out specialized metabolic tasks
organelles have... specialized structures, characteristic shapes, and specialized functions
examples of membranous organelles nuclues, mitochondria, lysosomes, peroxisomes, endoplasmic reticulum, and Golgi complex
examples of nonmembranous organelles ribosomes, centrosomes, centrioles, basal bodies
ribosomes tiny granules of RNA and protein; both free and attached; required for protein synthesis; found in nucleoli, in cytosol, on outer surfaces of rough ER, and nuclear envelope
golgi complex a small system of cisternae that synthesize carbohydrates and put the finishing touches on protein and glycoprotein synthesis
golgi complex receives... newly synthesized proteins from rough ER
golgi complex processes, sorts, packages, and delivers... proteins and lipids to plasma membrane, and packages the protein into membrane-bound Golgi vesicles
golgi vesicles form... lysosomes and secretory vesicles
some golgi vesicles migrate... to plasma membrane and fuse to it
lysosomes package of enzymes bound by a single unit membrane; extremely variable in shape
the function of lysosomes intracellular digestion of proteins, nucleic acids, complex carbohydrates, phospholipids, and other substances
autophagy digest and dispose worn out mitochondria and other organelles
autolysis "cell suicide", some cells destroy themselves after the completion of their function
peroxisomes resemble lysosomes but contain different enzymes and are not produced by the Golgi complex
function of peroxisomes use molecular oxygen to oxidize organic molecules
reactions initiated by peroxisomes produce... hydrogen peroxide (H2O2)
catalase breaks down exes peroxide to H2O and O2
peroxisomes neutralize... free radicals, detoxify alcohol, other drugs, and a variety of blood-borne toxins
peroxisomes break down... fatty acids into acetyl groups for mitochondrial use in ATP synthesis
peroxisomes are found in... all cells, but abundant in liver and kidney
mitochondria the main site for ATP generation - powerhouse of the cell
mitochondria are... large organelles where O2 combines with food to produce ATP
shapes of mitochondria... spheroid, rod-shaped, kidney-shaped, or threadlike
mitochondria are surrounded by... a double unit membrane
the inner membrane of mitochondria has folds called... cristae
the spaces between cristae in the inner membrane of mitochondria are called... matrix
the matrix in the inner membrane of mitochondria contains... ribosomes, enzymes used for ATP synthesis, small circular DNA molecule (mitochondrial DNA)
classes of diseases that cause muscle weakness and neurological disorders due to malfunctioning mitochondria: mitochondrial myopathy, mitochondrial encephalomyopathy, etc
centriole a short cylindrical assembly of microtubules arranged in nine groups of three microtubules each
centrosome small, clear area of cytoplasm where two centrioles lie perpendicular to each other
two kinds of inclusions stored cellular products, foreign bodies
examples of stored cellular products (inclusion) glycogen granules, pigments, and fat droplets
examples of foreign bodies (inclusion) viruses, intracellular bacteria, dust particles, and other debris phagocytized by a cell
inclusions are never enclosed... in a unit membrane
inclusions are not... essential for cell survival
making DNA involves... replication/duplication - making a copy of the genetic material in preparation for cell division
before a cell divides, it must... duplicate its DNA, so each daughter cell has a complete copy of all its genes
DNA replication must be... exact, because DNA controls all cellular function
during DNA replication, hydrogen bonds between nucleotides break... and the double stranded DNA helix unwinds. This occurs during S phase mitosis.
during DNA replication, a new strand is formed by pairing... complimentary bases from cytoplasm with the old strand. New hydrogen bonds form.
mutations changes in DNA structure due to replication errors or environmental factors (radiation, viruses, chemicals) - some mutations cause no ill effects
law of complimentary base pairing base sequence of one DNA strand determines the sequence of the other
the double helix unwinds from... histones
this opens one short segment of helix at a time to expose nitrogenous bases DNA helicase
replication fork point where DNA is opened up
DNA polymerase move along each strand of opened DNA during replication
DNA polymerase read... exposed bases and match complementary free nucleotides
the two separated strands of DNA are copied by separate polymerase molecules, proceeding in... opposite directions
DNA ligase joins short segments of DNA strand together
these cells contain identical genes all body cells except sex cells and some immune cells
different cells activate... different genes
any given cell uses _____ to _____ (fractions) of its genes one third to two thirds
genes not used by a cell... remain dormant and may be functional in other types of cells
DNA genetic material for coding proteins
types of RNA mRNA, rRNA, tRNA
mRNA - messenger RNA contains genetic information. it is a copy of a portion of the DNA
rRNA - ribosomal RNA the site of protein assembly.
ribosomes assemble amino acids in the order... directed by the codons of mRNA
tRNA - transfer RNA transports and positions amino acids on ribosomes on RER (rough endoplasmic reticulum) in final stage of protein synthesis
DNA and RNA are polymers formed... from monomer nucleotides through dehydration synthesis
two kinds of nucleic acids DNA (deoxyribonucleic acid, inherited genetic material); and RNA (ribonucleic acid; relays instructions from genes to gene product - protein).
involved in the storage and flow of information from gene to gene product both DNA and RNA
there are _____ (number) DNA molecules in the nucleus of most human cells 46
DNA and other nucleic acids are... polymers of nucleotides
each nucleotide consists of... one sugar (deoxyribose for DNA), one phosphate group, one nitrogenous base
four DNA nitrogenous bases A - adenine, G - Guanine, C - Cytosine, T - Thymine
two DNA nitrogenous bases that are purines (double ring) Adenine and Guanine
two DNA nitrogenous bases that are pyrimidines (single ring) Cytosine and Thymine
DNA base pairing A-T; C-G
molecular shape of DNA double helix
sidepiece of DNA double helix is a backbone composed of... phosphate groups alternating with the sugar deoxyribose
the steplike connections between the DNA double helix backbones are... pairs of nitrogenous bases
the nitrogenous bases in DNA are united by hydrogen bonds
gene a segment of DNA that codes for a specific protein
genes genetic instructions for synthesis of proteins
genome all the genes of a person
humans have an estimated _____ to _____ genes (number to number) 20,000 to 25,000
the genome in one person comprises _____ (percentage) of their total DNA 2%
______ (percentage) of DNA is noncoding 98%
non-coding DNA... plays a role in chromosome structure; regulation of gene activity; possibly no function at all ("junk" DNA)
human genome project identified the nitrogenous base sequences of 99% of human genome
genomics study of genome and how its genes and non-coding DNA interact to affect the structure and function of the whole organism
histones disc-shaped cluster of eight proteins; DNA molecules winds around this cluster
nucleosomes apparent division if histones into segments
nucleosome consists of core particle (histones with DNA around them); linker DNA (short segments of DNA connecting core particles)
a nucleosome is one-third shorter... than DNA alone
a chromatin-protein complex is... thrown into complex, irregular loops and coils; 1000 times shorter than original molecule
the chromatine is not a static strucrue... in nondividing cells
in nondividing cells, chromatin... changes moment to moment according to genetic activity of cell; genes get turned on and off
chromatin fine filamentous DNA material complexed with proteins
chromatin occurs as... 46 long filaments called chromosomes
in non-dividing cells, chromatin... is so slender it cannot be seen with light microscope
chromatin, under an electron microscope... has a granular appearance
each chromosome consists of... sister chromatids (2 parallel filaments of identical DNA) joined at a centromere
chromatin visible with light microscope when... in prophase, final coiling and condensing
RNA is much smaller... than DNA
DNA averages ____ (number) base pairs 100 million
mRNA - messenger RNA has over _____ bases 10,000
tRNA - transfer RNA has ___ to ___ (number to number) bases 70 to 90
RNA has only _____ (number) nucleotide strand one
the sugar in RNA is... ribose, not deoxyribose
the nitrogenous bases of RNA U (uracil), A (adenine), G (guanine), C (cytosine)
in RNA, uracil replaces... the thymine of DNA as a nitrogenous base
essential functions of RNA interprets code in DNA; uses DNA instructions for protein synthesis; leaves nucleus and functions in cytoplasm
number of amino acids that act as the bases of all proteins in the body 20
number of nucleotides that code for all genes 4 (AT,CG)
genetic code a system that enables these four nucleotides to code for the amino acid sequence of all proteins
base triplet a sequence of three DNA nucleotides that stands for one amino acid
codon the 3-base sequence in mRNA
there are _____ (number) possible codons that represent the 20 amino acids 64
_____ (number) codons code for amino acids 61
stop codons UAG, UGA, UAA - signal "end of message"
start codon AUG - codes for methionine, and begins the amino acid sequence of the protein
genomic medicine application of our knowledge of the genome to predict, diagnose, and treat disease
disorders where genomic medicine is applied cancer, Alzheimer disease, schizophrenia, obesity, AIDS, tuberculosis
genomic medicine allows for... the early detection of diseases, more effective clinical intervention
genomic medicine expands the potential for... gene-substitution therapy
protein synthesis involves... transcription and translation
protein synthesis: transcription copying - making RNA; transferring genetic code from DNA to RNA
protein synthesis: translation making proteins; from mRNA to proteins
DNA contains genetic template for... proteins
process of protein synthesis: DNA -> mRNA -> protein
making protein from DNA is a ____ (number) step process two
first step in making protein from DNA transcription
second step in making protein from DNA translation
transcription occurs... in the nucleus
description of transcription in protein synthesis mRNA copy of the gene made and carried to cytoplasm through nuclear pores to RER in cytoplasm
translation occurs... in the cytoplasm
description of translation in protein synthesis mRNA template serves as a series of codes for the amino acid sequence of the protein
transcription copying genetic instructions from DNA to RNA
RNA polymerase enzyme that binds to the DNA and assembles the mRNA
RNA polymerase opens up the DNA helix about... 17 base pairs at a time
RNA polymerase... reads base from one strand of DNA and makes a corresponding mRNA strand
where RNA polymerase finds a C on the DNA it adds G to the mRNA
where RNA polymerase finds an A on the DNA it adds U to the mRNA (unlike DNA replication, where T would be added)
RNA polymerase rewinds... the DNA helix behind it during transcription
one gene can code for... more than one protein
exons 'sense' portion of the immature RNA - will be translated to protein
introns 'nonsense' portion of the immature RNA - must be removed before translation
exons can be spliced together... into a variety of different mRNAs
translation the process that converts the language of nucleotides into the language of amino acids
ribosomes translate sequence of nucleotides into the sequence of amino acids
ribosomes occur mainly... in cytosol, on the surface of RER, and on the nuclear envelope
ribosomes consist of... two granular subunits, large and small; each made of several rRNA and enzyme molecules
mRNA molecule begins with... a leader sequence
leader sequnce of mRNA acts as... a binding site for small ribosomal subunit
a ribosmoe pulls mRNA through it like a ribbon... reading the bases as it goes
when the start codon (AUG) is reached... protein synthesis begins
all protein synthesis begins with methionine
translation process where ribosomes synthesize proteins using the mature mRNA transcript produced during transcription
mRNA moves from nucleus to cytoplasm, where... its codon binds to rRNA in a ribosome
ribosome binds and holds tRNA with its... specific amino acid
tRNA's in cytoplasm attach to... free amino acids in the cytoplasmic "pool"
tRNA carries its specific amino acid... to the ribosome
amino acid consists of triplet anticodon, which is a... complementary pair of codon of mRNA
enzyme releases amino acid to pair... with mRNA codon at ribosomes
polyribosome one mRNA holding multiple ribosomes
one ribosome can assemble a protein of ____ (number) amino acids in ____ (number) seconds 400, 20
______ (number) identical mRNA molecules may be undergoing simultaneous translation 300,000
a cell can produce _____ (number) protein molecules per second 150,000
once the primary structure (amino acid sequence) of protein synthesis has been completed protein synthesis is not yet finished
to be functional, an amino acid structure... must coil or fold into precise secondary and tertiary structures
proteins to be used in the cytosol are likely to be made... on free ribosomes in the cytosol
proteins destined for packaging into lysosomes ore secretion from the cell... are assembled on rough ER and sent to the Golgi complex for packaging
endoplasmic reticulum modifies protein by... posttranslational modification
posttranslational modification of proteins by the endoplasmic reticulum consists of... removing some amino acid segments, folding the protein, stabilizing protein with disulfide bridges; adding carbohydrates
vesicles fuse and unload proteins... into Golgi cisterna
Golgi complex further modifies... the protein, which is then released by exocytosis
protein processing and secretion, first stage: protein formed by ribosomes on rough ER
protein processing and secretion, second stage: protein packaged into transport vescile, which budes from ER
protein processing and secretion, third stage: transport vesicle fuse into clusters that unload protein into Golgi complex
protein processing and secretion, fourth stage: Golgi complex modifies protein structure
protein processing and secretion, fifth stage: Golgi vesicle containing finished protein is formed
protein processing and secretion, sixth stage: secretory vesicles release protein by exocytosis
cell cycle is made up of... cell division (mitosis) and interphase
cell division the process by which a parent cell reproduces itself by dividing into 2 cells (daughter cells)
two types of cell division somatic cell division; reproductive cell division
somatic cell division to replace dead, worn-out cells; results in diploid cells
mitosis nuclear division
cytokinesis cytoplasmic division
somatic cell division results in... diploid cells
reproductive cell division product of gametes
reproductive cell division results in... haploid cells
meiosis two cell division
cell cycle the cell's live cycle that extends from one division to the next
stages of cell cycle 1) mitosis + cytokinesis (M phase), 2) interphase
mitosis nuclear division; preserves diploid number of chromosomes
cytokinesis cytoplasmic division; cell divides into two daughter cells
interphase phase between mitotic divisions - not part of mitosis
cell cycle duration varies... between cell types
interphase, first stage: G1: cell growth
interphase, second stage: S: DNA replication
interphase, third stage: G2: cell growth and preparation for division
M phase consists of... mitosis and cytokinesis
during mitosis, DNA condenses... into chromosomes
during mitosis, the cell... replicates its nucleus and divides between 2 daughter cells
four sub-phases of mitosis for cell replication: prophase, metaphase, anaphase, telophase
during cytokinesis the cell's cytoplasm... divides, forming distinct cells
interphase is the collection of these phases: G1, S, and G2 phases
the G1 phase portion of interphase: the first gap phase; the interval between cell division and DNA replication
during the G1 phase portion of interphase: accumulates materials needed to replicate DNA; growth occurs as organelles double
the S phase portion of interphase: synthesis phase; duplicates centrioles
during the S phase portion of interphase: DNA replication occurs as chromosomes duplicate
the G2 phase portion of interphase: the second gap phase; interval between DNA replication and cell division
during the G2 phase portion of interphase: finishes centriole duplication; synthesizes enzymes that controll cell division; repairs DNA replication errors; growth occurs as cell prepares to divide
the M phase (not interphase) mitotic phase
during the M phase cell replicates its nucleus; pinches in two to form new daughter cells; mitosis and cytokinesis occur
the G0 (G zero) phase: cells that have temporarily or reversibly stopped dividing for a "rest"
during the G zero phase cells are said to have entered a state of quiescence
cells that enter into a G zero phase: muscle and nerve cells
interphase preceeds... mitosis
two processes that occur during interphase: protein synthesis, DNA replication
protein synthesis during interphase is needed... to maintain cell for cell growth and cell activities
DNA replication occurs during interphase... to prepare for cell division
G1 phase is the beginning... of DNA synthesis. no replication, but biosynthetic activities increase. cells increase in size and synthesize protein.
S phase of interphase... involves DNA replication
during G2 phase of interphase... there are two complete diploid sets of chromosomes
prophase the first stage of mitosis
metaphase second stage of mitosis
anaphase third stage of mitosis
telophase fourth stage of mitosis
early stage of prophase chromatin fibers shorten into distinct chromosomes
late stage of prophase nucleolus and nuclear membrane break down and disappear
mitotic spindle an assembly of microtubules that forms from centrioles
during late stage of prophase... centrioles move to opposite poles of the cell
during late stage of prophase... microtubules extend in length between the centrosomes
during late stage of prophase... eventually the spindle extends between two opposite poles of cell
metaphase is characterized by... the "metaphase plate"
the metaphase plate is... a midpoint region within the cell that is formed/defined by chromosomes (2 sister chromatids joined at centromere) aligning along the microtubules at the center of the miotic spindle
during anaphase, the centromeres... split into two, separating the chromatid pair
during anaphase, the spindle fibers... pull separated sister chromatids (chromosomes) to the opposite pole of the cell
during anaphase, microtubules pull chromosomes... and so they appear to be "V" shaped
telophase begins... after the chromosomal movement stops
during telophase, sets of chromosomes at opposite poles of the cell... uncoil and revert to chromatin form
during telophase, a new nuclear envelope... forms around each chromatin mass.
during telophase, within each new nuclear envelope... new nucleoli appear
during telophase, eventually... the miotic spindle breaks up
cytokinesis division of cells cytoplasm and organelles into two identical cells through formation of a cleavage furrow
during cytokinesis, a cell and its contents... divide into two daughter cells
Created by: jcoletaylor