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186 Cards in this Set

  • Front
  • Back
light microscopes LS's
uses light
electron microscope EM
used to study objects about 1 nm to 100 mm in size. focus a beam of electrons either through the specimin or onto its surface.
transmission EM
used to scan through specimen - focus beam of electrons through a specimin.
scanning EM
focus beam of electrons onto its surface.
prokaryotes vs eukaryotes
both have plasma membrane
both have cytosol with organelles
both have ribosomes
only euk has nucleus and is 10x larger than avg. prok cell
and only euk have internal membranes.
chromosomes grouped together in a region called nucleoids consist of bacteria and archaebacteria
consists of protists, fungae, plant and animal cells.
plasma membrane
creating a boundary for a cell, selectively permits the passage of materials into and out of cell. made up of phospholipids, proteins and associated carbohydrates
contains most of cells chromosomes
surrounded by double membrane
called nuclear envelope
MRNA is transcribed here and then sent out to the cytoplasm,
considered the control center of the cell.
complex of DNA and protein housed in nucleus; as cell gets ready for cell division, chromatin condenses into chromosomes
associated with chromitin, exists in a non-dividing nucleus and ribosomal RNA is produced here;
is not enclosed by membrane
made of RNA and protein, they are the sites of protein synthesis in the cell
free rhibosomes float in the cytosol and bound rhibosomes are bound to the endoplasmic reticulum
endoplasmic reticulum
makes up more than half the total membrane structure in many cells.
a network of membranes and sacs called cisternae;
its internal compartment called the cisternal space
smoothe ER
involved in synthesis of lipids and metabolism of carbs
rough ER
has many ribosomes attached to it
Golgi apparatus
when transport vesicles leave the ER they next travel to GA where their contents are modified, stored then sent on their way.
consists of flattened sacs of membrane again called cisternae;
two faces - cis face; trans face;
cis receives vesicles, trans ships them out
organelles in which respiration takes place.
has infolds called cristae;
single membrane bound compartments in cell responsible for various metabolic functions like break down purines; production of hydrogen peroxide and also the breakdown of hy per in plant cells
a network of fibers that runs through the entire cytoplasm; involved in cell motility and movment of structures within cell.
3 types of cytoskeleton
microtubules (make of tubulin)
intermediate filaments
appendages used for cell locomotion; protuding from cell surface in large numbers
cell structures found only in animal cells
membrane bound sacs of hydrolitic enzymes that can digest larger molecules;
have low internal ph;
can break down macro molecules for organic monomers to be excreted back into cytosol and recycled by cells;
as a cell ages the lysosomal membrane can break, thus digesting its cellular contents and destroying the cell.
a region located near the nucleus of animal cells in which microtubules grow;
located within centrosome of animal cells, replicate before cell division
appendages used for cell locomotion protruding from cell surface. most cells with flagellae possess only one.
extracellular matrix
external to plasma membrane
composed of glyco proteins secreted by cell
tight junctions
sections of animal cll membrane where two neighboring cells are fused
fasten adjacent animal cells together;
made up of intermediate filiments
gap junctions
provide channels between adjacent animal cells through which ions, sugars and other small molecules can pass
(cell structures found only in plants)
central vacules
membrane bound organelles whose function includes storage and breakdown of waste products;
found in both plant and algae cells;
sites of photosynthesis;
contain flattened membranes called thylacoids which form stacks called grana
channels that perforate adjacent cell walls and allow the cytosol to pass from cell to cell.
primarily made up of phosolipids and proteins; held together by weak interactions that cause the membrane to be fluid.
fluid mosaic model
membranes fluid and protein are embedded in or associated withteh phospholipid bi-layer.
integral proteins
completely embedded in the membrane.
peripheral proteins
loosely bound to the membrane surface
carbohydrates on the membrane
crucial in cell to cell recognition and in developing organisms for tissue differentiation; cell surface carbohydrates-many of which are oligosaccharides-vary from species to species and are the reason that blood transfusions are blood specific.
hydrocarbons, CO2, and O2
hydrophobic substances that can pass easily across the membrane
ions and polar molecules
cannot easily cross the membrane
passive defusion
diffusion that does not use energy
hypotonic vs hypertonic solution
hypotonic is a solution with lower solute concerntation
hypertonic - higher solute concerntration
channel vs carrier proteins
one provides the channel;
one binds to it and takes it across membrane
facilitated diffusion
diffucion across the cell membrane with the help of proteins that are specific to a certain substance
active transport
uses energy,
cells are moved against their concentration gradient
electrochemical gradient
a gradient caused by unequal amounts of negative and positive ions
electrogenic pump
generates voltage across membrane
ATP pump that transports specific solute and indirectly drives the transport of other substances
vesicles from cell's interior fuse with cell membrane expelling their contents to the exterior
basically reverse. - allows cell to take in macromolecules.
3 types of endocytosis
1. phagocytosis - cell wraps pseudopodia around substance and packages it within a large vesicle formed by membrane
2. pinocytosis - cell takes in small droplegs of extracellular fluid in small vesicles. not specific - no target molecules are taken in
3. receptor-mediated endocytosis. very specific. ligands bind to specific receptors on cell's surface. receptors usually clustered in coated pits. cases a vesicle to form around substance and then to pinch off into cytoplasm.
stored in chemical bonds between atoms, released when bonds are broken. some of energy released to work for cell, rest given off as heat
process by which molecules are broken down and energy is released.
2 types of catabolism
1. fermentation - breakdown of sugars that occurs in absence of O2.
2. cellular respiration - breakdown of sugars that occurs in the presence of O2
what is pirmary nutrient fuel molecule that is used in cellular respiration
standard way of representing the process of cell respiration - (equation)
C6H12O6 + 606 -> 6CO2 + 6H2O + Energy (ATP and heat)
energy is given off in the form of ATP
What is used go power all cellular activities
ATP in english
adenine triphosphate
when is ATP released as energy?
when enzymes in cell transfer one of its 3 phosphate groups to another molecules.
what is dephosphorylated ATP?
how is ATP recycled
ADP is rephophorylated by cell to form ATP again.
oxidation-reduction reaction
(redox reaction)
when electrons are transferred from one reacant to another
occurs in cytosol, glucose begins degredation process when it's broken down into 2 pyruvate molecules. 6 C glucose molecule is split into 2 3 C sugars through long series of steps
2 phases in glycolysis
ATP consuming phase
ADP producing stage
net results of glycolysis
2 ATP and 2 NADH
Krebs cycle
occurs in matrix of mitochondria;
job of breaking down glucose is completed and final product is CO2, carbon dioxide.
pg 52 dunno
how many steps in Krebs cycle
8; each catalyzed by different enzyme
net result of Kreb's cycle
4 CO2
electron transport chain
produces energy that drives the synthesis of ATP in oxidative phosphorlyation;
consists of molecules, mostly proteins, embedded in inner mitochondrial membrane
net result of electron transport chain
1. to move free energy down series of steps from FADH2 and NADH to O2.
2. to provide s source of energy for the creation of ATP through chemiosmosis
ATP synthetases
protein complexes in mitochonrial inner membrane; synthetases phosphorytetes ATP out of ADP plus inorganic phosphate.
is flow of electrons in electron transport chain exergonic?
what is energy given off (in above) used for?
to pump H+ ions across membrane concentration gradient
what do the H+ ions do next?
flow back across the membrane into mitochondrial matrix with their concentration gradient.
why can H+ ions only flow back through the ATP synthetases
they are the only regions in this membrane permeable to H+ ions
what does their flow do?
drive the oxidative phosphorylation of ADP to ATP
above process which is how the H+ gradient created by the electron transport chain is coupled to STP synthesis.
what is the final electron acceptor in the electron transport chain without which this chain will not function
in the absence of oxygen, what process does the cell go through?
anaerobic conditions
when there is no O2 present
aerobic conditions
when O2 is present
what takes place in anaerobic conditions
what takes place in aerobic conditions
cell respiration
what does fermentation consist of
glycolysis and reactions that regenerate NAD+ (so that it can be reused during glycolysis)
two common types of fermentation
alcohol fermentation and lactic acid fermentation
what happens in alcohol fermentation
pyruvate is converted to ethanol, releasing CO2 and oxidizing NADH in the process to create more NAD+
what happens in lactic acid fermentation
pyruvate is reduced by NADH (and NAD+ is created) and lactate is formed as a waste product
light energy from sun is converted to chemical energy that can be stored in sugars and other organic compounds.
plant cell organelles - mostly located in cells that make up mesophyll tissue (part of leaf)
tiny pores in exterior of lower epidermis of leaf cell, through which CO2 can enter and O2 can exit leaf
dense fluid-filled area inside the inner membrane of chloroplasts
thylakoid membranes
withint stroma, a vst network of interconnected membranes in which cholorophyll is located.
thylakoid space
inside thylakoid membranes
located in thylakoid membranes - light-absorbing pigment that drives photosynthesis and gives plants green color
equasion for overall reaction of photosynthesis
6CO2 + 12H2O + Light energy a C6H12O6 = 6)2 + 6H2O
what does photosynthesis enable the plant to produce using light energy?
organic compounds and O2
what re 2 main parts of photosynthesis
light reactions and the Calvin cycle
what happens in light reactions
solar energy is converted to chemical energy.
light is absorbed by chlorophyll and drives transfer of electrons from water to NADP+ (to create NADPH) which stores them
water is split and O2 is given off.
what do light reactions also produce in photophosphorylation
ATP from ADP
what are net products of light reactions
NADPH (stores electrons), ATP and O2.
Calvin cycle
CO2 from teh air in incorporated into organic molecules in carbon fixation. fixed C is used to make carbs.
what is used to power C fixation
What else does Calvin cycle use in the course of its reactions
what kind of energy is light
electromagnetic energy
how does it behave
as if it is made up of discrete particles called phtons, each of which has a fixed quantity of energy.
what are pigments
substances that absorb light
do pigments absorb light of all wavelengths?
no. different pigments absorbe light of different wavelengths.
What does Chlorophyll pigment absorb
red, blue and green
what does chlorophyll absorb light energy in the form of?
What happens when chlor. absorbs light enerby in the form of phonton?
one of molecule's electrons is raised to an orbital of higher potential energy. Chlorophyll is said to then be in an excited state
where are phonos of light absorbed by certain groups of pigment molecules
in thalakoid membrane of chloroplsats.
what are these groups called
What do photosystems have
an antenna complex made up of chlorophyll olecules and caretenoid molecules
what are caretenoid molecules
accessory pigments in teh thylakoid membrane
what are the 2 photosystems in teh thylakoid membrane that are imortant to photosynthesis
photosystem I PSI and photosystem II (PSII)
reaction center
in each photosystem; the site of the first light-driven chemical reaction of photosynthesis
how many major steps of light reactions of photsynthesis are there
first step
PSII absorbs light
what is nonometer wavelength range of absorbed light
rest of first step
electron in reaction center chlorophyll (P680) becomes excited and then captured by a promary electron acceptor. The reaction center chlorophyll is oxidized and needs and electron
second step
an enzyme supplies mission electron taken from photolysis water (splitting of water) to P680. water is plit and a free oxygen is created which combines with another oxygen to form O2.
third step
original excited electron passes from primary electron acceptor of PSII to PSI through an electron transport chain.
step 4
energy from transfer of electrons down the electron transport chian is used to phsophorylate ADP to ATP in thylakoid membrane, in a process called noncyclic photophosphorylation.same process as in chemiosmosis. later this ATP will be used as energy in the formation of carbs in the dark reactions or Calvin cycle
step 5
electrons that get to end of electron transport chain are donated to chlorophyll in P700 of photosystem I
when is this need for an electron by PSI created
when light energy excites and electron in P700, and that electron is take up by the promary acceptor of PSI
step 6
the primary electron acceptor of PSI passes along the excited electrons along to another electron transport chain, which transmits them to ferredoxin, and then finally to NADP+, which is reduced to NADPH, the second of two important light-reaction products.
cyclic electron flow
an alternative to noncyclic electron flow; PSII is bypassed and the electrons from ferredoxin cycle back to a protion of the electron transport chain of PSII and its cytochromes and then to P700. Neither NADPH nor oxygen is produced, but ATP is still a product. This process is called cyclic photophosphorylation.
where can cyclic photophosphorylation occur
in some photosynthetic bacteria
what does nonelectric electron flow produce
nearly equal quantities of ATP and NADPH,
what is CO2 converted to in teh calvin cycle
carbohydrate called blyceraldehyde-3-phosphate (G3P)and ATP and NAFPH are both consumed.
how many rotations must the cycle go through in order to make one molecule of G3P
3, and fix 3 molecules of
how many steps in Calvin cycle
step 1
3 CO2 molecules are attached to 3 ribulose bisphosphate molecules (RuBPs;
these reactions are catalyzed by rubisco to produce and unstable product that immediately splits into 2 3 C compounds called 3-phosphoglycerate
step 2
the 3-phosphoglycerate molecules are phosphorylated to become 1, 3-disphosphoglycerate.
step 3
NADPHs reduce the 1, 3-disphosphoglycerates to create glyceraldehyde-3-phosphates (G3P)
step 4
RuBP is regenerated as the 5 G3Ps are reworked into 3 of the starting molecules, with teh expenditure of 3 ATP molecules.
what are the results of the Calvin cycle
9 molecules of ATP are consumed (to be replenished by the light reactions;
6 molecules of NADPH are consumed (also to be replenished by the light reactions;)
the G3P that was created is later metabolized into larger carbohydrates.
how much G3P is produces for each trip through the C. cycle
how many other ways are there for plant to fix carbon - what are they
C4 photosynthesis and CAM photosynthesis.
what uses C4 fixation instead of C3 fixation (standard Calvin cycle)
plants living in hot, dry climates
what is difference between C4 fixation and C3 fixation
first C compoind formed in the Calvin cycle contains 4 carbons instead of 3
2 different kinds of photosynthetic cells in C4 plants
bundle-sheath cells, and mesophyll celss.
what are bundle-sheath cells
cells grouped around the leaf's veins,
mesophyll cells
dispersed elsewhere around the leaf.
how many steps in C4 photosynthesis
step 1
CO2 is added to phosphoenolpyruvate (PEP) to form the 4-C compound Oxaloacetate or oxaloacetic acid. This enzyme is catalyzed by PEP carboxylase and this process is very quick and efficient.
step 2
the mesophyll cells export the oxaloacetate to the bundle sheath cells which break the oxaloacetate back down into CO2
step 3
the CO2 is converted into carbohydrates through the regular Calvin cycle
purpose of C4 phtosynthesis
speeds up regular phtosynthesis since PEP carboxylase works much faster than rubisco, the enzyme of C3 photosynthesis.
what is the alternative to C3 phtotsynthesis
CAM photosynthesis
what is CAM photosynthesis
an adaptation to hot dry climates. plants open their stomata at night and close them during the day so they experience minimal water loss during day. (non-CAM do opposite). Because stomata are closed during day, COw can't get into the leaves during the day so they take it up at night.
CO2 cycle in CAM plants
take in CO2 at night, convert it into arious organic compounds and put it inot temp storage in their vacuoles. IN morning stomata close, plants release stored CO2 so that they can use lgiht energy to perform normal reactions of photosynthesis.
Do all process C3, C4, and CAM use the Calvin cycle?
what must happen before the cell can divide (cell cycle - changed subject)
the cell's genome must be copied
what is cell's genome
its complete complement of DNA in the form of chromosomes
what is humber of chromosomes in human somatic cells
how many chromosomes in human gametes (sperm and egge cells which are hapliod
what is process of mitosis - what does it do
process by which somatic cells divide and create daughter cells tha tcontain the same diploid chromosome number as the organism.
what happens just prior to mitosis
chromosomes are replicated, each duplicated chromosome consist of 2 sister chromatids attached by a centromere
what is mitosis
division of the cell's nucleus
what follows mitosis
cytokinesis - division of cell's cytoplasm.
human somatic cells start with how many homologous chromosomes
how many inherited from each parent
what heppens next
chromosomes are doubled but then mitosis reduces the chromosomes nmber back to its regular 46 number again.
somatic cell reproduction always results in offspring with what diploid chromosome number in relation to parent
process by which gametes are produced which occurs only in ovaries and testes of humans
in meiosis daughter cells have how many chromosomes in relation to parents
half. 23.
how many phases in cell cycle (mitosis)
2 - mitotic phase (10% of cycle), interphase (90%)
mitotic phase
consists of mitosis and cytokinesis
consists of G1 phase, S phase and G2 phase
what does cell do during interphase
cell prepares for cell division by growing, duplicating cell organelles replicating hisones and other proteins associated with DNA and replicating its DNA
how many phases can mitosis be broken down into
phase 1
Prophase: chromatin becomes more tightly coiled into discrete chromosomes, the nucleioli disappear, and the mitotic spindle (consisting of microtublules extending from teh 2 centrosomes) begins to form in teh cytoplasm.
phase 2
Prometaphase: the nuclear envelope begins to fragment so that the microtubules can begin to attach to teh chromosomes, which have further condensed. Each of the 2 chromatids from the chromosome pair now has a kinetochore at its centromere region, to which teh microtubles will begin to atttache. nuclioli have disappeared
phase 3
metaphase: centrioles have now migrated to opposite poles in cell, chromosome line up on the metaphase plate at the equator of cell. All kinetochores have attached microtublues and all microtubules together are called spindle at this point
phase 4
anaphase: sister chromatids begin to separate, pulled apart by retracting microtubules. Cell also elongates as poles elongate. by end of anaphase opposite ends of cell both contain complete and equal sets of chromosomes
phase 5
telephase: nuclear envelopes reform around sets of chromosomes located at opposite ends of cell. chromatin fiber of chromosomes becomes less condensed, and cytokinesis begins, durin gwhich the cytoplasm of cell is divided. in animal cells a cleavage furrow is created that eventually pinches off to form 2 cells; in plant cells a cell plate is created that eventually creates 2 daughter cells
what controls the steps of the cell cylce
cell cycle control system.
how does control system work
moves cell through its stages by a series of checkpoints at which signals the cell either to continue or to stop.
major cell cycle check points
G1 phase checkpoint, G2 phase checkpoint and Mphase checkpoint
most important check point
G1 - if cell gets the go ahead signal at this checkpoint it will complete the whole cell cycle and divide. if not - it enters a nondividing phase called G0 phase.
proteins that control the cell cycle. - exist in cell at all times but are active only when they are connected to cyclin proteins. thus they are cyclin-dependant kinases (CDK)
MPF (maturation-promoting factor)
a CDK. MPF trigger the cell to pass the G2 checkpoint into M phase.