3 MAIN PARTS OF A CELL
1.nucleus
2.plasma membrane
3.cytoplasm
NUCLEUS
large organelle that houses most of a cell's dna
CHROMOSOME
a single molecule of DNA associated with several proteins,contains thousands of hereditary units
GENES
thousands of hereditary units. controlls most aspects of cellular structure and function
PLASMA MEMBRANE
forms the cell's flexible outer surface, separating the cell's internal environment fromm the external environment. it is a selective barrier that regualtes the flow of materials into and out of a cell. plays a key role in communication among cells and be
CYTOPLASM
consists of all the cellular contents between the plasma membrane and the nucleus.l this compartment has two components: cytosol and organelles.
CYTOSOL
fluid portion of cytoplasm, contains water, dissolved solutes, anbd suspended particles.
ORGANELLES
has a specific shape and specific function
NUCLEUS
large organelle that houses most of a cell's DNA.
STRUCTURE OF PLASMA MEMBRANE:
the basic structural framework of the plasma membrane is the lipid bilayer. two back to back layers made up of three types of lipid molecules-phospholipids,cholesterol and glycolipids. about 75% of the membrane lipids are phospholipids, lipids that contai
AMPHIPATHIC
both polar and nonpolar parts
ROLE OF PHOSPHOLIPIDS:
water loving the head (blue) face a watery fluid on either side
PLASMA MEMBRANE:
flexible but sturdy structure that surrounds the cytoplasm.
membrane is 50% lipid, 50% protein
lipid is barrier to entry and exit of polar substances
proteins are "gatekeepers" regulate traffic
50 lipid molecules for every protein molecule
LIPID BILAYER MADE UP OF THREE PARTS:
phospholipids,cholesterol, and glycolipids
GLYCOLIPIDS
carbohydrate group form a polar head that appears only in the membrane layer which faces which faces the extracellular fluid
CHOLESTEROL
is weakly amphiphotic and are interspersed among other lipids
PHOSPHOLIPDS
comprise 75% of lipids
PHOSPHOLIPID BILAYER
2 parralel layers of molecules, each molecule is amphipathic, (has both a polar and nonpolar region), polar parts are hdrophyllic, nonpolar parts are hydrophobic
CHOLESTEROL
comprises 20% of cell membrane fluid,interspersed among the other lipids in both layers,stiff steroid rings and hydrocarbon tail are nonpolar and hide in middle of cell membrane
INTEGRAL PROTEINS
extend or cross the entire lipid bilayer among the fatty acid tails of the phospholipid molecules.CAN'T LIVE WITHOUT THEM. EMBEDDED.
PERIPERAL PROTEINS
found at the inner and outer surface of the membrane and can be stripped away from the membrane without disturbing membrane integrity.COULD LIVE WITHOUT THEM. transports substances in and out of cells.hangs out on edge of surfaces.
FUNCTIONS OF MEMBRANE PROTEINS:
formation of channel, transports protien,receptor proteins,cell identity marker,linker, anchors protein in cell membrane or to other cells, allow cell movement, helps maintain cell shape and structure and membrane proteins act as enzyme and speed up react
MEMBRANE FLUIDITY
is a fluid structure, rather like cooking oil, because most of the membrane lipids and many of the membrane proteins easily move in the bilayer. membrane lipids and proteins are mobile in their own half of the bilayer.
CHOLESTEROL IN MEMBRANE FLUIDITY
serves to stabilize the membrane and reduce membrane fluidity.
SELECTIVE PERMEABILITY
the property of a membrane by which it permits the passage of certain substaqnces but restricts the passage of others.
HOW IS THE PLASMA MEMBRANE SELECTIVELY PERMIABLE?
*the lipid bilayer protion of the membrane is permeable to small, nonpolar, uncharged molecules but impermeable to ions and charged or polar molecules.
*the membrane is permiable to water
*transmembrane proteins act as channels or transporters increase pe
MACROMOLECULES
unable to pass through the plasma membrane except by vesicular transport.
CONCENTRATION GRADIENT
is the difference in the concentration of a chemical between one side of the plasma membrane and the other.
WHAT ELEMENT IS MORE CONCENTRATED OUTSIDE THE PLASMA MEMBRANE?
oxygen and sodium ions outside the cell membrane
WHAT ELEMENTS ARE MORE CONCENTRATED IN THE PLASMA MEMBRANE?
carbon dioxide and potassium ions
ELECTRICAL GRADIENT
inner surface of the plasma membrane is more negatively charged and outside is more positively charged , this is the difference in electrical charges between two regions.
HOW DO CONCENTRATION AND ELECTRICAL GRADIENTS AFFECT THE PERMEABILITY OF A PLASMA MEMBRANE?
they help move substances across the plasma membrane. in many cases a substance will move across a plasma membrane down its concentration gradient . it will move from more concentrated to less to reach equillibrium. negative charge will move to a positive
IMPORTANCE OF ELECTRICAL AND GRADIENT CONCENTRATIONS:
important to cell life.
ELECTROCHEMICAL GRADIENT
combined concentration and electrical gradients
TRANSPORT ACRSS THE PLASMA MEMBRANE CONSISTS OF:
1.mediated transport
2. nonmediated transport
3.active transport
4.passive transport
5.vesicular transport
MEDIATED TRANSPORT
moves material with the help of a tranporter protein (need assistance)
NONMEDIATED TRANSPORT
does not use a transporter protein (diffusion)
ACTIVE TRANSPORT
uses ATP to drive substances against their concentration gradients
PASSIVE TRANSPORT
moves substances down thier concentration gradient with only their kinetic energy (using thier own energy)
VESICULAR TRANSPORT
move materials across membranes in small vesicles--either by exocytosis or endocytosis.
OSMOSIS
net movement of a solvent through a selectively permeable membrane, or in living systems, the movement of water (the solute) from an area of higher concentration to an area of lower concentration across the membrane. passive process
HOW DO CELLS USE THE OSMOSIS PROCESS?
osmosis is the movement of water molecules through a selectively permeable membrane. want equilibrium in cells.
TONICITY
measure of a solutions ability to change the volume of cells by altering their water concentration
ISOTONIC SOLUTION
red blood cells maintian their normal shape
HYPOTONIC
red blood cells undergo hemolysis. too much water and the cell can burst
HYPERTONIC
red blood cells undergo crenation. water leaves the cell
PRIMARY ACTIVE TRANSPORT
most prevalent transport mechanism. uses ATP and and energy obtained through hydrolisis
SODIUM ION/ POTASSIUM ION PUMP
all cells have thousands of sodium-patassium pumps in thier plasma membrane. maintain a low concentration of Na+ in the cytosol by pumping them into the extracellular fluid against the Na+ concentration gradient. at the same time, the pump moves K+ into c
SECONDARY ACTIVE TRANSPORT
energy stored in Na+ or H+ concentration gradient is used to drive other substanfes across the membrane against their own concentration gradients. one way street
SYMPORTERS
transports two substances in the same direction. they can do their job because the Na+/K+ pump does its job
ANTIPOERTERS
move two substances in oposite directions across the membrane. two way street. can transport because the Na+/K+ pump does its job
VESICULAR TRANSPORT OF PARTICLES
1. endocytosis
2.exoctytosis
ENDOCYTOSIS
materials move into a cell in a vesicle formed from the plasma membrane. requires ATP
EXOCYTOSIS
materials move out of a cell by the fusion with the plasma membrane of vesicles formed inside the cell. requires ATP. vesicles from inside cell, fuse to cell membrane and release their content. release digbestive enzymes, hormones, neurotransmitters or wa
PHAGOCYTOSIS (endocytosis)
cell eating by macrophages and WBC's. particles binds to receptor proetins or whole bacteria or virus are englufed and later digested
CYTOSOL
inracellular fluid, the fluid portion of the cytoplasm that surrounds organelles and constitutes about % of total cell volume. contains inclusions and dissolved solutes. compsed mostly of water , plus proetins ,carbohydrates, lipids, and inorganic substan
ORGANELLE
specialized structures within the cell that have characteristic shapes, they perform specific functions in cellular growth, maintenance, and reproudction.
CYTOSOL FUNCTION
is the medium in which many metabolic reaction occurs.
CYTOSKELETON
network of protein filaments that extends throughout the cytosol. Filaments throught the cytosol.
FUNCTION OF CYTOSKELETON
cell support and shape, organization of chemical reaciotn, cell and organelle movement, and continuall reorganize
CENTROSOME
located near the nucleus. tubulin complexes are the organizing centers for growth of the mitotic spinds,which plays a critical roll in cell divison.
CILLIA (short) AND FLAGELLA (much longer)
microtubules are the dominant component of this and have motile projections of the cell surface.
MICROVILLI
take in nutrient, on surface to increase surface area for absorption. finger-like structures that expand surface area ex: cilia, flagella
RIBOSOMES
are tind spheres consisting of ribosomal rna nad several ribosomal proteins
RIBOSOME FUNCTION:
site of protein synthesis. made in the nucleolus, once produces, the large and small subunits exit the nucleus seperately then come together in the cytoplasm
ENDOPLASMIC RETICULUM
network of membranes. transports, synthesizes, packages, and stores proteins. detoxifies chemicals and releases calcium inon involved in muscle contraction.
ROUGH ER
studded with ribosomes. about proteins
SMOOTH ER
does not contain ribosomes on its membrane surface. detoxifying
GOLGI COMPLEX
UPS MAN.. sort and transport. main function is to process, sort,a nd deliver proteins and lipids to the plasma membrane, lysosomes, and secretory vesicles.
LYSOSOMES
stomach of the cell. low ph very acidic. membrane enclosed besicle that contains powerful digestive enzymes. internal ph reaches 5.0 function includes digestin substancves and recycling organelles.
PERIOXOSOMES
are similar in structure to lysosomes, but are smaller. they contain enzymes that oxidases enzymes that can oxidize (remove hydrogen atoms from..) varous organic substances. for instance, amino acids and fatty acids are oxsidized in this as part of normal
PROTEOSOMES
destroy uneeded, damaged, or faulty proteins. they contain proteases which cut proteins into small peptides. thought to be a foctor in several diseases.
MITOCHONDRIA
POWERHOUSE..bound by double membrane. the outer membrane is smooth, the inner membrane arranged in folds called cristae. this allows for increased surface area for chemical rections of cellular respiration.
SITE OF ATP PRODUCTION BY A CELL:
mitochondria
MITOCHONDRIA
self replicate using thier own dna.
NUCLEUS (director)
most prominent feature of a cell. within the nucleus are the cell's hereditary untis, called genes, which are arranged in single file along chromosomes.
NUCLEAR ENVELOPE
seperates the nucelus from the cytoplasm. both layers of the envelope are lipid bilayers
PARTS OF A NUCLEUS:
nuclear envelope which is perforated by channels called nuclear pores, nucleoli, and genetic material (DNA)
JOB OF NUCELUS:
nuclear pores control the movement of substances between the nucleus and cytoplasm, nucleoli produce robosomes and chromosomes consist of genes that control cellular structure and direct cellular functions.
PROTEIN SYNTHESIS
much of the cellular machinery is devoted to synthesizing large numbers of diverse proteins. the proteins determine the physical and chemical characteristics of cells. the instructions for protein synthesis is found in the dna in the nucleus. protein syth
TRANSCRIPTION
RNA= outside nucleus DNA= inside nucleus. process by which genetic information encoded in DNA is copied onto a strand of RNA called messenger RNA (mRNA), which directs protein synthesis. mRNA takes information outside the cell.
TRANSLATION
reading the mRNA nucleotide sequence to determine the amino acid sequence of the proetien. mRNA has information written in Spanish and need to write to english.
MITOSIS (everything else)
orderly division of the nucleus of a cell that ensures that each new nucleus has the same number and kind of chromosomes as the original nucleus.the process includes the replication of chormosomes and the distribution of the two sets of chromosomes into t
MEIOSIS (gammets)
a type of cell division that occurs during production of gametes, involving two successive nuclear division that result in cells with the haploid (n) number of chromosomes.
CYTOKINESIS
distribution of the cytoplasm into two seperate cells during cell divison, coordinated with nuclear divison (mitosis)
MITOSIS
splits into two cells. ends with cytokinesis
MEIOSIS
splits into four cells and has a stage one and two
CELL DIVISION
1.prophase
2.metaphase
3.anaphase
4.telaphase
PROPHASE
chromatin fibers condense and shorten into chromosomes that are visible under the light mjicroscope.
METAPHASE
microtubles of the mitotic spindle align the centromeres of the chromatid pairs at the exact center of the mitotic spinde.
ANAPHASE
centromeres split, sepataing the two members of each chromatid pair, which move toward opposite poles of the cell
TELOPHASE
final stages of mitosis, telophase, begins after chromosomal movement stops.
WHEN DOES CYTOKYNESIS BEGIN?
late anaphase with the formation of a cleavage furrow, a slight indentation of the plasma membrane, and is completed after telphase.
TELOMERS AND AGING CELLS
specific DNA sequence found only at the tips of each chromosome. these pieces of DNA protect th etips of chromosomes from erosion and from stricking to one another. after many cycles of cell division they can be comepletely gone and even some of the funct
FREE RADICALS AND AGING CELLS
roduce oxidative damage in lipids, proteins or nucleic acids by "stealing" an electron to accompany their unpaired electrons.
CELL IDENTITY MARKER CHANGES IN AGING CELLS:
the immune system may start to attack the body's own cells.as changes in the proteins on the plasma membrane of cells increase, the autoimmune response intensifies, producing the well known signs of aging.
3 MAIN PARTS OF A CELL
1.nucleus
2.plasma membrane
3.cytoplasm
NUCLEUS
large organelle that houses most of a cell's dna
CHROMOSOME
a single molecule of DNA associated with several proteins,contains thousands of hereditary units
GENES
thousands of hereditary units. controlls most aspects of cellular structure and function
PLASMA MEMBRANE
forms the cell's flexible outer surface, separating the cell's internal environment fromm the external environment. it is a selective barrier that regualtes the flow of materials into and out of a cell. plays a key role in communication among cells and be
CYTOPLASM
consists of all the cellular contents between the plasma membrane and the nucleus.l this compartment has two components: cytosol and organelles.
CYTOSOL
fluid portion of cytoplasm, contains water, dissolved solutes, anbd suspended particles.
ORGANELLES
has a specific shape and specific function
NUCLEUS
large organelle that houses most of a cell's DNA.
STRUCTURE OF PLASMA MEMBRANE:
the basic structural framework of the plasma membrane is the lipid bilayer. two back to back layers made up of three types of lipid molecules-phospholipids,cholesterol and glycolipids. about 75% of the membrane lipids are phospholipids, lipids that contai
AMPHIPATHIC
both polar and nonpolar parts
ROLE OF PHOSPHOLIPIDS:
water loving the head (blue) face a watery fluid on either side
PLASMA MEMBRANE:
flexible but sturdy structure that surrounds the cytoplasm.
membrane is 50% lipid, 50% protein
lipid is barrier to entry and exit of polar substances
proteins are "gatekeepers" regulate traffic
50 lipid molecules for every protein molecule
LIPID BILAYER MADE UP OF THREE PARTS:
phospholipids,cholesterol, and glycolipids
GLYCOLIPIDS
carbohydrate group form a polar head that appears only in the membrane layer which faces which faces the extracellular fluid
CHOLESTEROL
is weakly amphiphotic and are interspersed among other lipids
PHOSPHOLIPDS
comprise 75% of lipids
PHOSPHOLIPID BILAYER
2 parralel layers of molecules, each molecule is amphipathic, (has both a polar and nonpolar region), polar parts are hdrophyllic, nonpolar parts are hydrophobic
CHOLESTEROL
comprises 20% of cell membrane fluid,interspersed among the other lipids in both layers,stiff steroid rings and hydrocarbon tail are nonpolar and hide in middle of cell membrane
INTEGRAL PROTEINS
extend or cross the entire lipid bilayer among the fatty acid tails of the phospholipid molecules.CAN'T LIVE WITHOUT THEM. EMBEDDED.
PERIPERAL PROTEINS
found at the inner and outer surface of the membrane and can be stripped away from the membrane without disturbing membrane integrity.COULD LIVE WITHOUT THEM. transports substances in and out of cells.hangs out on edge of surfaces.
FUNCTIONS OF MEMBRANE PROTEINS:
formation of channel, transports protien,receptor proteins,cell identity marker,linker, anchors protein in cell membrane or to other cells, allow cell movement, helps maintain cell shape and structure and membrane proteins act as enzyme and speed up react
MEMBRANE FLUIDITY
is a fluid structure, rather like cooking oil, because most of the membrane lipids and many of the membrane proteins easily move in the bilayer. membrane lipids and proteins are mobile in their own half of the bilayer.
CHOLESTEROL IN MEMBRANE FLUIDITY
serves to stabilize the membrane and reduce membrane fluidity.
SELECTIVE PERMEABILITY
the property of a membrane by which it permits the passage of certain substaqnces but restricts the passage of others.
HOW IS THE PLASMA MEMBRANE SELECTIVELY PERMIABLE?
*the lipid bilayer protion of the membrane is permeable to small, nonpolar, uncharged molecules but impermeable to ions and charged or polar molecules.
*the membrane is permiable to water
*transmembrane proteins act as channels or transporters increase pe
MACROMOLECULES
unable to pass through the plasma membrane except by vesicular transport.
CONCENTRATION GRADIENT
is the difference in the concentration of a chemical between one side of the plasma membrane and the other.
WHAT ELEMENT IS MORE CONCENTRATED OUTSIDE THE PLASMA MEMBRANE?
oxygen and sodium ions outside the cell membrane
WHAT ELEMENTS ARE MORE CONCENTRATED IN THE PLASMA MEMBRANE?
carbon dioxide and potassium ions
ELECTRICAL GRADIENT
inner surface of the plasma membrane is more negatively charged and outside is more positively charged , this is the difference in electrical charges between two regions.
HOW DO CONCENTRATION AND ELECTRICAL GRADIENTS AFFECT THE PERMEABILITY OF A PLASMA MEMBRANE?
they help move substances across the plasma membrane. in many cases a substance will move across a plasma membrane down its concentration gradient . it will move from more concentrated to less to reach equillibrium. negative charge will move to a positive
IMPORTANCE OF ELECTRICAL AND GRADIENT CONCENTRATIONS:
important to cell life.
ELECTROCHEMICAL GRADIENT
combined concentration and electrical gradients
TRANSPORT ACRSS THE PLASMA MEMBRANE CONSISTS OF:
1.mediated transport
2. nonmediated transport
3.active transport
4.passive transport
5.vesicular transport
MEDIATED TRANSPORT
moves material with the help of a tranporter protein (need assistance)
NONMEDIATED TRANSPORT
does not use a transporter protein (diffusion)
ACTIVE TRANSPORT
uses ATP to drive substances against their concentration gradients
PASSIVE TRANSPORT
moves substances down thier concentration gradient with only their kinetic energy (using thier own energy)
VESICULAR TRANSPORT
move materials across membranes in small vesicles--either by exocytosis or endocytosis.
OSMOSIS
net movement of a solvent through a selectively permeable membrane, or in living systems, the movement of water (the solute) from an area of higher concentration to an area of lower concentration across the membrane. passive process
HOW DO CELLS USE THE OSMOSIS PROCESS?
osmosis is the movement of water molecules through a selectively permeable membrane. want equilibrium in cells.
TONICITY
measure of a solutions ability to change the volume of cells by altering their water concentration
ISOTONIC SOLUTION
red blood cells maintian their normal shape
HYPOTONIC
red blood cells undergo hemolysis. too much water and the cell can burst
HYPERTONIC
red blood cells undergo crenation. water leaves the cell
PRIMARY ACTIVE TRANSPORT
most prevalent transport mechanism. uses ATP and and energy obtained through hydrolisis
SODIUM ION/ POTASSIUM ION PUMP
all cells have thousands of sodium-patassium pumps in thier plasma membrane. maintain a low concentration of Na+ in the cytosol by pumping them into the extracellular fluid against the Na+ concentration gradient. at the same time, the pump moves K+ into c
SECONDARY ACTIVE TRANSPORT
energy stored in Na+ or H+ concentration gradient is used to drive other substanfes across the membrane against their own concentration gradients. one way street
SYMPORTERS
transports two substances in the same direction. they can do their job because the Na+/K+ pump does its job
ANTIPOERTERS
move two substances in oposite directions across the membrane. two way street. can transport because the Na+/K+ pump does its job
VESICULAR TRANSPORT OF PARTICLES
1. endocytosis
2.exoctytosis
ENDOCYTOSIS
materials move into a cell in a vesicle formed from the plasma membrane. requires ATP
EXOCYTOSIS
materials move out of a cell by the fusion with the plasma membrane of vesicles formed inside the cell. requires ATP. vesicles from inside cell, fuse to cell membrane and release their content. release digbestive enzymes, hormones, neurotransmitters or wa
PHAGOCYTOSIS (endocytosis)
cell eating by macrophages and WBC's. particles binds to receptor proetins or whole bacteria or virus are englufed and later digested
CYTOSOL
inracellular fluid, the fluid portion of the cytoplasm that surrounds organelles and constitutes about % of total cell volume. contains inclusions and dissolved solutes. compsed mostly of water , plus proetins ,carbohydrates, lipids, and inorganic substan
ORGANELLE
specialized structures within the cell that have characteristic shapes, they perform specific functions in cellular growth, maintenance, and reproudction.
CYTOSOL FUNCTION
is the medium in which many metabolic reaction occurs.
CYTOSKELETON
network of protein filaments that extends throughout the cytosol. Filaments throught the cytosol.
FUNCTION OF CYTOSKELETON
cell support and shape, organization of chemical reaciotn, cell and organelle movement, and continuall reorganize
CENTROSOME
located near the nucleus. tubulin complexes are the organizing centers for growth of the mitotic spinds,which plays a critical roll in cell divison.
CILLIA (short) AND FLAGELLA (much longer)
microtubules are the dominant component of this and have motile projections of the cell surface.
MICROVILLI
take in nutrient, on surface to increase surface area for absorption. finger-like structures that expand surface area ex: cilia, flagella
RIBOSOMES
are tind spheres consisting of ribosomal rna nad several ribosomal proteins
RIBOSOME FUNCTION:
site of protein synthesis. made in the nucleolus, once produces, the large and small subunits exit the nucleus seperately then come together in the cytoplasm
ENDOPLASMIC RETICULUM
network of membranes. transports, synthesizes, packages, and stores proteins. detoxifies chemicals and releases calcium inon involved in muscle contraction.
ROUGH ER
studded with ribosomes. about proteins
SMOOTH ER
does not contain ribosomes on its membrane surface. detoxifying
GOLGI COMPLEX
UPS MAN.. sort and transport. main function is to process, sort,a nd deliver proteins and lipids to the plasma membrane, lysosomes, and secretory vesicles.
LYSOSOMES
stomach of the cell. low ph very acidic. membrane enclosed besicle that contains powerful digestive enzymes. internal ph reaches 5.0 function includes digestin substancves and recycling organelles.
PERIOXOSOMES
are similar in structure to lysosomes, but are smaller. they contain enzymes that oxidases enzymes that can oxidize (remove hydrogen atoms from..) varous organic substances. for instance, amino acids and fatty acids are oxsidized in this as part of normal
PROTEOSOMES
destroy uneeded, damaged, or faulty proteins. they contain proteases which cut proteins into small peptides. thought to be a foctor in several diseases.
MITOCHONDRIA
POWERHOUSE..bound by double membrane. the outer membrane is smooth, the inner membrane arranged in folds called cristae. this allows for increased surface area for chemical rections of cellular respiration.
SITE OF ATP PRODUCTION BY A CELL:
mitochondria
MITOCHONDRIA
self replicate using thier own dna.
NUCLEUS (director)
most prominent feature of a cell. within the nucleus are the cell's hereditary untis, called genes, which are arranged in single file along chromosomes.
NUCLEAR ENVELOPE
seperates the nucelus from the cytoplasm. both layers of the envelope are lipid bilayers
PARTS OF A NUCLEUS:
nuclear envelope which is perforated by channels called nuclear pores, nucleoli, and genetic material (DNA)
JOB OF NUCELUS:
nuclear pores control the movement of substances between the nucleus and cytoplasm, nucleoli produce robosomes and chromosomes consist of genes that control cellular structure and direct cellular functions.
PROTEIN SYNTHESIS
much of the cellular machinery is devoted to synthesizing large numbers of diverse proteins. the proteins determine the physical and chemical characteristics of cells. the instructions for protein synthesis is found in the dna in the nucleus. protein syth
TRANSCRIPTION
RNA= outside nucleus DNA= inside nucleus. process by which genetic information encoded in DNA is copied onto a strand of RNA called messenger RNA (mRNA), which directs protein synthesis. mRNA takes information outside the cell.
TRANSLATION
reading the mRNA nucleotide sequence to determine the amino acid sequence of the proetien. mRNA has information written in Spanish and need to write to english.
MITOSIS (everything else)
orderly division of the nucleus of a cell that ensures that each new nucleus has the same number and kind of chromosomes as the original nucleus.the process includes the replication of chormosomes and the distribution of the two sets of chromosomes into t
MEIOSIS (gammets)
a type of cell division that occurs during production of gametes, involving two successive nuclear division that result in cells with the haploid (n) number of chromosomes.
CYTOKINESIS
distribution of the cytoplasm into two seperate cells during cell divison, coordinated with nuclear divison (mitosis)
MITOSIS
splits into two cells. ends with cytokinesis
MEIOSIS
splits into four cells and has a stage one and two
CELL DIVISION
1.prophase
2.metaphase
3.anaphase
4.telaphase
PROPHASE
chromatin fibers condense and shorten into chromosomes that are visible under the light mjicroscope.
METAPHASE
microtubles of the mitotic spindle align the centromeres of the chromatid pairs at the exact center of the mitotic spinde.
ANAPHASE
centromeres split, sepataing the two members of each chromatid pair, which move toward opposite poles of the cell
TELOPHASE
final stages of mitosis, telophase, begins after chromosomal movement stops.
WHEN DOES CYTOKYNESIS BEGIN?
late anaphase with the formation of a cleavage furrow, a slight indentation of the plasma membrane, and is completed after telphase.
TELOMERS AND AGING CELLS
specific DNA sequence found only at the tips of each chromosome. these pieces of DNA protect th etips of chromosomes from erosion and from stricking to one another. after many cycles of cell division they can be comepletely gone and even some of the funct
FREE RADICALS AND AGING CELLS
roduce oxidative damage in lipids, proteins or nucleic acids by "stealing" an electron to accompany their unpaired electrons.
CELL IDENTITY MARKER CHANGES IN AGING CELLS:
the immune system may start to attack the body's own cells.as changes in the proteins on the plasma membrane of cells increase, the autoimmune response intensifies, producing the well known signs of aging.