Term
|
Definition
– unicellular organisms: one cell divides,
reproduces entire organism
– Multicellular organisms: Development from a
fertilized cell, growth, repair |
|
|
Term
|
Definition
| the life of a cell from formation to its own division |
|
|
Term
Match
Dividing amoeba, dividing sand dollar embryo cells, dividing bone cells
Growth and development, Reproduction, Tissue renewal |
|
Definition
amoeba - reproduction
sand dollar embryo cells - growth and development
bone cells - tissue renewal |
|
|
Term
|
Definition
| produced when nucleotide sequences from two different sources (like two species) combined in vitro to one DNA molecule |
|
|
Term
|
Definition
| direct manipulation of genes for practical purposes |
|
|
Term
|
Definition
| manipulation of organisms or their genetic components to make useful products |
|
|
Term
|
Definition
| preparing gene-sized pieces of DNA in identical copies to work directly with specific genes; most methods use bacteria and their plasmids |
|
|
Term
|
Definition
| small circular DNA molecules in bacteria, replicate separately from bacterial chromosome |
|
|
Term
| Cloned genes are useful for |
|
Definition
| making copies of a particular gene, producing protein product from said gene |
|
|
Term
| Gene cloning, result and why it is useful |
|
Definition
using bacteria to make multiple copies of a gene.
-foreign DNA inserted into plasmid, recombinant plasmid inserted into bacterial cell
-bacterial reproduction results in cloning of the plasmid, including foreign DNA
Result: production of multiple copies of a single gene
Why: amplify a gene, make a protein product |
|
|
Term
|
Definition
| enzymes that cut DNA at a limited number of specific locations, specific to a certain sequence where they break sugar-phosphate backbones |
|
|
Term
|
Definition
| Restriction enzymes cut DNA molecules at these specific DNA sequences |
|
|
Term
|
Definition
| the resulting fragments of DNA from restriction enzyme cuts |
|
|
Term
|
Definition
| when DNA molecules are cut in a staggered way so that there is a single stranded end to a double stranded restriction fragment |
|
|
Term
| How sticky ends become covalently bonded |
|
Definition
|
|
Term
|
Definition
| DNA molecule that can carry foreign DNA into a host cell and replicate there; the original plasmid |
|
|
Term
| Steps to clone a gene (hummingbird beta-globin) in a bacterial plasmid |
|
Definition
-hummingbird genomic DNA and a bacterial plasmid are isolated
-both are digested with the same restriction enzyme
-fragments are mixed, DNA ligase is added to bond the fragment sticky ends
-some recombinant plasmids now contain hummingbird DNA
-the DNA mixture is added to bacteria that have been genetically engineered to accept it
-the bacteria are plated on a type of agar that selects for the bacteria with recombinant plasmids
-this results in the cloning of many hummingbird DNA fragments, including the beta-globin gene |
|
|
Term
|
Definition
(can be made using bacteria)
the collection of recombinant vector clones produced by cloning DNA fragments from an entire genome |
|
|
Term
| Nucleic acid hybridization |
|
Definition
base-pairing with complementary sequence on another nucleic acid molecule
-Used to screen library to find clones with gene of interest |
|
|
Term
|
Definition
Nucleic acid hybridization requires this
-Short, single-stranded nucleic acid (DNA or RNA) with sequence known to be complementary to at least part of the gene of interest
-marked (radioactive isotope, fluorescent tag, etc.)
-apply to plate of material from library |
|
|
Term
| Complementary DNA (cDNA) Library |
|
Definition
-made by cloning DNA made in vitro by reverse transcription of all the mRNA produced by a particular cell (uses the enzyme reverse transcriptase to do this)
-represents only part of the genome: only the subset of genes transcribed into mRNA in the original cells |
|
|
Term
| Most cell division results in ________ cells with ____________ genetic information, DNA |
|
Definition
|
|
Term
| A special type of division, ___________, produces nonidentical daughter cells |
|
Definition
|
|
Term
|
Definition
| all DNA in a cell; can consist of single or many DNA molecules |
|
|
Term
| DNA molecules in a cell are packaged into ___________ |
|
Definition
chromosomes
-each species has a set number of chromosomes (humans 46, hedgehogs 90) |
|
|
Term
|
Definition
non-reproductive cells
have two sets of chromosomes |
|
|
Term
|
Definition
reproductive cells
have one set of chromosomes (humans 23) |
|
|
Term
| Before cell division: DNA replicated; chromosomes _________ |
|
Definition
|
|
Term
| Duplicated chromosome has two ___________ _______________ |
|
Definition
|
|
Term
|
Definition
| site where chromatids are most closely attached; the "waist" of the chromatids |
|
|
Term
| What is chromatin made up of? |
|
Definition
|
|
Term
(Eukaryotic cell division)
Mitosis
Cytokinesis |
|
Definition
division of genetic material in nucleus
division of cytoplasm |
|
|
Term
|
Definition
|
|
Term
|
Definition
| 90% of cycle; cell growth and copying of chromosomes in preparation for cell division |
|
|
Term
| The overall cell cycle consists of _________ and _________ |
|
Definition
| Mitotic (M) phase and Interphase |
|
|
Term
Interphase:
G1 Phase
S Phase
G2 Phase |
|
Definition
"first gap"; cell growth
"synthesis" (of DNA); cell growth and chromosome duplication
"second gap"; cell growth |
|
|
Term
|
Definition
| Prophase, prometaphase, metaphase, anaphase, telophase |
|
|
Term
| At what stage is the cell just prior to mitosis? |
|
Definition
|
|
Term
|
Definition
-nuclear envelope surrounds nucleus
-centrosome has duplicated
-chromatin has duplicated (but not yet condensed) |
|
|
Term
|
Definition
| microtubule organizing center, contains two centrioles |
|
|
Term
|
Definition
apparatus of microtubules that controls chromosome movement during mitosis
-includes centrosomes, spindle microtubules, and asters |
|
|
Term
|
Definition
| radial array of short microtubules extending from each centrosome |
|
|
Term
|
Definition
| chromatin condenses into sister chromatides; assembly of spindle microtubules begins, centrosomes migrate to opposite poles as spindle microtubules grow out from them |
|
|
Term
|
Definition
a structure of proteins associated with specific sections of DNA at each centromere
-a chromosome has two kinetochores facing in opposite directions |
|
|
Term
|
Definition
| nuclear envelope fragments; chromatids get kinetochores; some spindle microtubules attach to kinetochores and jerk back and forth; non-kinetochore microtubule attachments also form |
|
|
Term
|
Definition
-centrosomes at opposite poles
-chromosomes line up at the metaphase plate (midway point between the spindle's two poles
-kinetochore arranged so for each chromosome, one kinetochore attached towards each pole |
|
|
Term
|
Definition
sister chromatids separate (cohesion proteins are cleaved); each chromosome moves along kinetochore microtubules toward opposite poles
-microtubules shorten by depolymerizing at kinetochore ends
-non-kinetochore microtubules from opposite poles overlap and push against each other, elongating the cell |
|
|
Term
|
Definition
| genetically identical daughter nuclei form at opposite ends of the cell; nuclear envelopes form; chromosomes become less dense; spindle dissolves |
|
|
Term
| What is the metaphase plate made of? |
|
Definition
|
|
Term
| Cytokinesis (animal cells) |
|
Definition
| occurs by cleavage: a process of forming a cleavage furrow or contractile ring of actin microfilaments associated with myosin that pinches the parent cell in two |
|
|
Term
| Cytokinesis (plant cells) |
|
Definition
| occurs by forming a cell plate: coalesced vesicles containing cell wall materials eventually grow to fuse with membrane around cell, dividing cell in two |
|
|
Term
| What is the order of stages in the cell cycle? |
|
Definition
|
|
Term
| Cell cycle control system |
|
Definition
directs sequential events of cell cycle
-regulates by both internal and external controls
-has specific checkpoints |
|
|
Term
| Checkpoints (in cell cycle control system) |
|
Definition
| time point where cycle stops until it receives go-ahead signal |
|
|
Term
|
Definition
-if go-ahead signal at G1, cell usually completes S, G2, and M phases
-if no go-ahead signal, cell exits cycle, switching to G0 phase (non-dividing state) |
|
|
Term
|
Definition
|
|
Term
|
Definition
enzymes that activate/inactivate other proteins by phosphorylating
-go ahead signals at G1, G2 checkpoints |
|
|
Term
|
Definition
| protein that cyclically fluctuates concentration in cell |
|
|
Term
| Cyclin-dependent kinases (CDKs) |
|
Definition
kinases that drive the cell cycle, present consistently but usually in inactive form
-activity of both fluctuates during cell cycle
-control the cell cycle by phosphorylating other proteins |
|
|
Term
| Maturation-Promoting Factor (MPF) |
|
Definition
a cyclin-CDK complex that triggers passing G2 checkpoint into M phase
-cyclins accumulate in G2
-associate with CDK molecules
-MPF phosphorylates proteins that initiate mitosis |
|
|
Term
| MPF functions in beginning mitosis directly as a kinase and indirectly by activating kinases |
|
Definition
-phosphorylated proteins of nuclear lamina causing fragmentation of nuclear envelope (direct)
-influences chromosome condensation and spindle formation (direct)
-activates proteins that initiate mitosis (indirect) |
|
|
Term
| Cell contains large quantity of MPF only at certain times |
|
Definition
-CDK level constant
-cyclin fluctuates, rising during S and G2, peaking at M
-MPF bonds most at end of G2, high for M phase
-MPF initiates destruction of own cyclin at anaphase
-CDK persists, ready for new surge of cyclin |
|
|
Term
| Internal signals (M checkpoint) |
|
Definition
| kinetochores not attached to spindle microtubules send molecular signal that delays anaphase |
|
|
Term
|
Definition
-Growth factors: proteins that stimulate other cells to divide
-Density dependent inhibition: crowded cells stop dividing
-Anchorage dependence: cells must be attached to internal surface in order to divide |
|
|
Term
| Cancer cells exhibit ________ density-dependent inhibition _____ anchorage dependence |
|
Definition
|
|
Term
|
Definition
-respond abnormally to body's control mechanisms
-may not need growth factors to grow and divide
-may make own growth factor
-may convey growth factor's signal without presence of growth factor
-may have abnormal cell cycle control system |
|
|
Term
|
Definition
| process of normal cell converting to cancerous cell |
|
|
Term
|
Definition
| mass of abnormal cells within otherwise normal tissue |
|
|
Term
|
Definition
lump whose cells remain at original site
lump whose cells invade surrounding tissues |
|
|
Term
|
Definition
| to export cancer cells to new parts of body, where they may form secondary tumors |
|
|
Term
| Cancer results from genetic changes that affect cell cycle control |
|
Definition
-can be caused by mutations to genes that regulate cell growth and division
-can be caused by agents that increase the rate of mutation (radiation, chemical carcinogens, X-rays) |
|
|
Term
|
Definition
|
|
Term
|
Definition
the corresponding normal genes responsible for normal cell growth and/or division
-conversion of proto-oncogene to oncogene can lead to abnormal stimulation of cell cycle |
|
|
Term
| Proto-oncogenes can be converted to oncogenes with increased protein product or protein activity by |
|
Definition
-movement of DNA within the genome
-if near active promoter, transcription may increase
-amplification of a proto-oncogene
-increases copies of the gene
-point mutations in the proto-oncogene or its control elements
-causes increase in gene expression or change in protein |
|
|
Term
What problems can result from a point mutation in a proto-oncogene?
a. multiple copies of the proto-oncogene (amplification)
b. protein amplification
c. hyperactive protein product
d. degradation-resistant protein product
e. C and D |
|
Definition
|
|
Term
|
Definition
codes for Ras protein (G protein used in growth factor signaling cell cycle stimulation-mutations can lead to production of a hyperactive Ras protein and increased cell division
-mutations to this gene are common in human cancers |
|
|
Term
| Tumor-suppressor genes and functions |
|
Definition
product inhibits cell division; helps prevent uncontrolled cell growth
-mutations that decrease their protein products may contribute to cancer onset
-stimulates growth through absence of suppression
Functions: repair damaged DNA, control cell adhesion, inhibit the cell cycle in the cell-signaling pathway |
|
|
Term
| DNA damage triggers signal to _____ cell division |
|
Definition
halt/stop
-this pathway involves tumor-suppressor genes |
|
|
Term
|
Definition
a tumor-suppressor gene, codes for transcription factor promoting a cel cycle inhibition protein
-mutations in p53 prevent cell cycle suppression |
|
|
Term
| Multistep model of cancer development |
|
Definition
-multiple mutations are needed for full-fledged cancer; incidence increases with age
-at the DNA level, a cancerous cell is usually characterized by at lease one active oncogene and the mutation of several tumor-suppressor genes |
|
|
Term
|
Definition
| one parent produces genetically identical offspring (clones) by mitosis |
|
|
Term
|
Definition
| two parents produce offspring with unique combinations of genes inherited from the two parents |
|
|
Term
|
Definition
| arrangement of chromosomes in pairs starting with the longest chromosome |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| Female sex chromosomes; male sex chromosomes |
|
Definition
|
|
Term
|
Definition
| the 22 pairs of chromosomes that do not determine sex (in humans) |
|
|
Term
|
Definition
| two sets of chromosomes; 46 in humans; 23 from each parent |
|
|
Term
|
Definition
| alternate forms of genes located on homologous chromosomes |
|
|
Term
|
Definition
| gamete; sperm or egg cell; contains a single set of chromosomes (23 in humans) |
|
|
Term
| In an unfertilized egg cell, what sex chromosome will be present in the haploid set of chromosomes? In a sperm cell? |
|
Definition
|
|
Term
|
Definition
| the union of gametes (sperm and egg) |
|
|
Term
|
Definition
the fertilized egg, has one set of chromosomes from each parent
-produces somatic cells by mitosis and develops into an adult |
|
|
Term
|
Definition
-mitotically dividing and G0-arrested cells
-make up vast majority of individual's tissues
-diploid in nature |
|
|
Term
|
Definition
-pockets of specialized cells
-produce gametes (egg/sperm)
-incorporated into ovaries and testes
-undergo meiosis
-produce haploid gametes |
|
|
Term
|
Definition
-a special form of cell division that produces gametes
-occurs in reproductive organs: ovaries and testes, produces egg or sperm
-each gamete has one set of autosomes (22) and a single sex chromosome
-like mitosis, meiosis is preceded by the replication of chromosomes |
|
|
Term
| Meiosis takes place in two sets of cell divisions, called |
|
Definition
|
|
Term
|
Definition
-four daughter cells, rather than the 2 daughter cells in mitosis
-each daughter cell has only half as many chromosomes as the parent cell |
|
|
Term
| A cell with 40 chromosomes undergoes meiosis, How many products form, each containing how many chromosomes? |
|
Definition
| 4 cells, each with 20 chromosomes |
|
|
Term
|
Definition
-preceded by interphase, in which chromosomes are replicated to form sister chromatids
-the sister chromatids are genetically identical and joined at the centromere
-the single centrosome replicates, forming two centrosomes |
|
|
Term
| Division in meiosis I occurs in four phases: |
|
Definition
-Prophase I
-Metaphase I
-Anaphase I
-Telophase I and cytokinesis |
|
|
Term
| How does meiosis allow genetic mixing? Synapsis |
|
Definition
| homologous chromosomes physically connect to each other during Prophase I |
|
|
Term
| How does meiosis allow genetic mixing? Crossing over |
|
Definition
| genetic rearrangement between non-sister chromatids, exchanging corresponding segments of DNA which occurs in Prophase I |
|
|
Term
| How does meiosis allow genetic mixing? Independent assortment of chromosomes |
|
Definition
| maternal/paternal chromosomes randomly orient during Metaphase I |
|
|
Term
| Division in meiosis II is _______ as mitosis |
|
Definition
| same (prophase II, metaphase Ii, anaphase II, telophase II and cytokinesis) |
|
|
Term
Mitosis ______ number of chromosome sets, producing cells genetically ________ to parent cells
Meiosis ________ number of chromosome sets, producing cells that are genetically ______ from the parent cell and each other |
|
Definition
conserves, identical
reduces, different |
|
|
Term
| An individual's genotype for two traits is AaBb. What are the alleles found in four different gametes produced by this individual? |
|
Definition
|
|
Term
|
Definition
each pair of chromosomes sorts maternal and paternal homologues into daughter cells independently of the other pairs
-the number of combinations possible when chromosomes assort independently into gametes in 2^n, where n is the haploid number
-for humans (n=23), there are more than 8 million (2^23) possible combinations of chromosomes |
|
|
Term
| Crossing over produces RECOMBINANT CHROMOSOMES |
|
Definition
-combined genes inherited from each parent
-crossing over begins very early in prophase I, as homologous chromosomes pair up gene by gene
-in crossing over homologous portions of two non-sister chromatids trade places
-crossing over contributes to genetic variation by combining DNA from two parents into a singe chromosome |
|
|
Term
|
Definition
-partial degradation of sugars, occurs without oxygen
-uses substrate-level phosphorylation instead of an electron transport chain to generate ATP
-consists of glycolysis plus reactions that regenerate NAD+, which can be reused by glycolysis
-two common types: alcohol fermentation and lactic acid fermentation |
|
|
Term
|
Definition
| consumes organic molecules and oxygen, yields ATP |
|
|
Term
|
Definition
-consumes compounds other than oxygen
-uses electron transport chain with an electron acceptor other than oxygen (ex: sulfate ion which produces hydrogen sulfide instead of water) |
|
|
Term
|
Definition
-a catabolic, exergonic, oxygen requiring process that uses energy extracted from macromolecules (glucose) to produce energy (ATP) and water
-includes both aerobic and anaerobic respiration, but often refers to just aerobic respiration |
|
|
Term
| Cellular respiration equation |
|
Definition
glucose + 6 oxygen yields 6 carbon dioxide + 6 water + ATP
Glucose is C6H12O6 |
|
|
Term
|
Definition
| chemical reactions that transfer electrons between reactants |
|
|
Term
|
Definition
| when a substance loses electrons or is oxidized |
|
|
Term
|
Definition
| when a substance gains electrons or is reduced |
|
|
Term
| Some redox reactions do not transfer electrons but _____ |
|
Definition
| change the electron sharing in covalent bonds due to differences in electronegativity |
|
|
Term
| During cellular respiration, the fuel (glucose) is _________ and oxygen is ___________ |
|
Definition
|
|
Term
|
Definition
-an oxidizing agent in cellular respiration
-reduced form: NADH, stored energy used to aid in synthesis of ATO |
|
|
Term
|
Definition
-a number of molecules (mostly proteins) built into inner mitochondrial membrane (prokaryotes: plasma membrane) that breaks the "fall" of electrons into many small steps
-electrons drop in free energy as they go down the chain and are finally passed to oxygen, forming water
-Function: break large free energy drop from food to oxygen into smaller steps that release manageable amounts of energy
-first carrier in chain is NADH, transfers electron to FMN (reducing it)
-reduced proteins pass electron to next protein, becoming oxidized; finally pass electrons to oxygen at end of chain |
|
|
Term
| What is the route of most electrons moving through cellular respiration? |
|
Definition
| Glucose -> NADH -> electron transport chain -> oxygen |
|
|
Term
| 3 Stages of cellular respiration |
|
Definition
| glycolysis, citric acid cycle, oxidative phosphorylation |
|
|
Term
|
Definition
-"splitting of sugar"
-breaks down glucose into two molecules of pyruvate
-net release 2 ATP and 2NADH
-occurs in cytoplasm
-two major phases: energy investment phase and energy payoff phase (both 5 steps) |
|
|
Term
|
Definition
| completes breakdown of glucose to carbon dioxide |
|
|
Term
| Oxidative phosphorylation |
|
Definition
| accounts for most ATP synthesis; powered by redox reaction, 90% of ATP generated here; comprised of electron transport chain and chemiosmosis |
|
|
Term
| Substrate-level phosphorylation |
|
Definition
| when enzyme transfers phosphate group from substrate molecule to ADP, making ATP; in oxidative phosphorylation, inorganic phosphate is added to ADP |
|
|
Term
| What steps of cellular respiration contain reactions that form ATP through substrate-level phosphorylation? |
|
Definition
| glycolysis and citric acid cycle |
|
|
Term
| Oxidation of pyruvate to Acetyl CoA |
|
Definition
| if oxygen present, pyruvate enters mitochondria via active transport and converts to acetyl CoA through 3 reactions, prep for citric acid cycle |
|
|
Term
|
Definition
-also called Krebs cycle
-Main function: metabolic furnace oxidizing organic fuel (NADH and FADH2 production)
-Input: Acetyl CoA (derived from pyruvate)
-Output: 3 carbon dioxide, 1 ATP, 4NADH, 1FADH2
-this considers the output of the pyruvate oxidation to Acetyl CoA
-8 steps, each catalyzed by a specific enzyme
-Step 1: acetyl group combines with oxaloacetate, forming citrate
-next seven steps: decomposition to oxaloacetate |
|
|
Term
|
Definition
An energy coupling mechanism
-process in which energy, stored as hydrogen ion gradient across a membrane, is used to drive cellular work such as synthesis of ATP
-uses ATP synthase |
|
|
Term
|
Definition
| Hydrogen ion gradient that can perform work |
|
|
Term
|
Definition
-enzyme (protein complex) that makes ATP from ADP and inorganic phosphate
-found in membranes of mitochondria and chloroplasts (and plasma membrane of prokaryotes)
-uses exergonic flor of hydrogen ion to drive phosphorylation to make ATP
-when ion binds in rotor, changes shape and spins protein complex
-internal rod spinning changes shape of catalytic knob, activating sites for ADP and inorganic phosphate to produce ATP |
|
|
Term
| How is the Hydrogen ion gradient maintained in chemiosmosis? |
|
Definition
-major function of electron transport chain
-as electrons are moved down the chain, there are places in the protein complexes where hydrogen ions are taken from the matrix and released into the inter-membrane space |
|
|
Term
| Why does FADH2 produce less energy than NADH? |
|
Definition
| FADH2 deposits its electrons later in the chain so there is less opportunity for protons to move across membrane for these electrons; smaller change in free energy |
|
|
Term
| What is the total ATP yield for cellular respiration? |
|
Definition
about 38 ATP, the rest is lost as heat
inexact number |
|
|
Term
| Application for hibernating animals |
|
Definition
| uncoupling proteins in inner mitochondrial membranes of brown fat tissue allow protons to flow down concentration gradient without generating ATP, so uses all oxidation energy to make heat slowly through winter |
|
|
Term
| Glycolysis can produce ATP ________ oxygen |
|
Definition
| with or without; not dependent on oxygen |
|
|
Term
| Without oxygen, glycolysis couples with fermentation or __________ respiration to produce ATP |
|
Definition
|
|
Term
|
Definition
-pyruvate is converted to ethanol in two steps, with the first releasing carbon dioxide (bubbles in yeast that cause bread to rise)
-by yeast: brewing, winemaking, and baking |
|
|
Term
|
Definition
-pyruvate is reduced directly by NADH, forming lactate as end product, with no release of carbon dioxide
-some fungi and bacteria use this to make cheese and yogurt
-human muscle cells use this to generate ATP when oxygen is scarce in conditions such as vigorous exercise |
|
|
Term
|
Definition
| carry out fermentation or anaerobic respiration; cannot survive in the presence of oxygen |
|
|
Term
|
Definition
| can survive using either fermentation or cellular respiration |
|
|
Term
| Catabolism of various food molecules |
|
Definition
| monomers can enter cellular respiration process at different points |
|
|
Term
| Regulating cellular respiration |
|
Definition
| may use molecules for other functions, don't want constant high respiration; use phosphofructokinase |
|
|
Term
|
Definition
| allosteric enzyme that responds to inhibition and activation for feedback regulation of cellular respiration |
|
|
Term
|
Definition
| organism that produces organis matter from light or chemical energy, carbon dioxide, and water |
|
|
Term
|
Definition
-process that converts solar energy into chemical energy, using the energy of sunlight to make organic molecules from water and carbon dioxide
-occurs in plants, algae, certain other protists (eukaryotes), and some prokaryotes |
|
|
Term
|
Definition
| organelles structurally similar to photosynthetic bacteria |
|
|
Term
|
Definition
| the green pigment within chloroplasts, absorbs light energy that drives synthesis of organic molecules |
|
|
Term
| What does endosymbiont theory say about chloroplasts? |
|
Definition
| They were originally photosynthetic prokaryotes living inside eukaryotes |
|
|
Term
|
Definition
| interior tissue of leaf where most chloroplasts are; cell has 30-40 chloroplasts |
|
|
Term
|
Definition
| microscopic pores where carbon dioxide enters and oxygen exits leaf |
|
|
Term
|
Definition
| dense fluid in chloroplasts |
|
|
Term
|
Definition
| connected sacs in chloroplast, membranes contain chlorophyll; may stack in grana columns |
|
|
Term
|
Definition
| 6 carbon dioxide + 12 water + light energy yields glucose + 6 oxygen + 6 water |
|
|
Term
| Photosynthesis is a redox process; what is oxidized? what is reduced? |
|
Definition
|
|
Term
| 2 Stages of Photosynthesis |
|
Definition
1. Light reactions
2. Calvin Cycle |
|
|
Term
|
Definition
-the photo part of photosynthesis; in the thykaloids, converts solar energy to chemical energy
-split water
-release oxygen
-reduce NADP+ to NADPH
-generate ATP from ADP through photophosphorylation |
|
|
Term
|
Definition
-the synthesis part of photosynthesis; in the stroma, makes sugar
-forms sugar from carbon dioxide, using ATP and NADPH
-begins with carbon fixation
-doesn't directly require light, but takes place during the day because it needs ATP and NADPH from light reactions |
|
|
Term
|
Definition
| using chemiosmosis to power the addition of phosphate group to ADP to make ATP |
|
|
Term
|
Definition
| incorporating carbon dioxide into organic molecules |
|
|
Term
|
Definition
| distance between wave crests; determines the type of electromagnetic energy |
|
|
Term
|
Definition
| entire range of electromagnetic energy |
|
|
Term
|
Definition
| wavelengths that produce colors we see |
|
|
Term
|
Definition
substances that absorb visible light
-different kinds absorb different wavelengths
-if not absorbed, reflected or transmitted
-pigment absorbs light, boosts electron to another orbital with more potential energy; pigment goes from ground state to unstable excited state
-excited electron falls back down to ground state, release excess energy as heat
-in isolation, some pigments emit light as well as heat (fluorescence)
Leaves are green because chlorophyll reflects and transmits green light, absorbs other colors of light |
|
|
Term
|
Definition
plot of pigment's light absorption vs wavelength
-for chlorophyll a, violet-blue, red light best for photosynthesis |
|
|
Term
|
Definition
| main photosynthetic pigment |
|
|
Term
|
Definition
| broaden spectrum for photosynthesis (chlorophyll b) |
|
|
Term
|
Definition
| absorb excessive light that would damage chlorophyll |
|
|
Term
|
Definition
| a reaction-center complex (type of protein complex) surrounded by light-harvesting complexes |
|
|
Term
|
Definition
| proteins with special pair of chlorophyll a molecules |
|
|
Term
| Light-harvesting complexes |
|
Definition
variable pigment molecules bound to proteins
-funnel photon energy to reaction center |
|
|
Term
| Primary electron acceptor |
|
Definition
| in the center of the reaction center, accepts an excited electron from chlorophyll a |
|
|
Term
|
Definition
functions first (numbers describe order of discovery), best at absorbing 680 nm wavelength
-the reaction-center chlorophyll a of PSII is called P680 |
|
|
Term
|
Definition
best at absorbing 700 nm wavelength
-reaction-center chlorophyll a is called P700 |
|
|
Term
| Linear electron flow (light reactions) |
|
Definition
-involves both photosystems to produce ATP and NADPH
1. photon hits a pigment and its energy is passed along pigment molecules until it excited P680
2. excited electron from P680 transferred to primary electron acceptor P680+ (P680 that is missing an electron) , a very strong oxidizing agent
3. water is split by enzymes, and the electrons transfer from hydrogen atoms to P680+, reducing it to P680
-oxygen is released as by-product of this reaction
-hydrogen ion released into thykaloid lumen
4. each electron "falls" down an electron chain from the primary electron acceptor of PSII or PSI
-energy released by fall drives creation of proton gradient across thykaloid membrane
5. diffusion of hydrogen protons across membrane drives ATP synthesis
6. in PSI (like PSII), light energy excites P700, process repeats to electron transport chain
7. in second electron transport chain - no proton gradient, no ATP production
8. then transferred to NADP+ to for NADPH (now available for Calvin cycle reactions) |
|
|
Term
|
Definition
-uses only PSI to produce ATP (not NADPH)
-generates surplus ATP, satisfying higher demand of calvin cycle
-some bacteria only have PSI, evolved before linear electron flow?
-may protect cells from light-induced damage |
|
|
Term
| Chemiosmosis in chloroplasts |
|
Definition
| trasform light energy into chemical energy of ATP, electrons come from water; protons pumped into thykaloid space, drive ATP synthesis and diffuse back into stroma |
|
|
Term
| Three phases in Calvin Cycle |
|
Definition
-carbon fixation (catalyzed by rubisco)
-reduction
-regeneration of the carbon dioxide acceptor (RuBP) |
|
|
Term
|
Definition
-regenerates its starting material after molecules enter and leave the cycle
-like citric acid cycle but requires ATP
-builds sugar (G3P) from carbon dioxide by using ATO and the reducing power of NADPH electrons
-for net synthesis of 1 G3P, 3 rotations on cycle, fixing 3 molecules of carbon dioxide
-uses 9 ATP, 6 NADPH; yields G3P |
|
|
Term
| Plants that use the Calvin cycle are called __ plants |
|
Definition
|
|
Term
|
Definition
process in which rubisco adds oxygen instead of carbon dioxide into Calvin cycle; consumes oxygen and organic fuel, releases carbon dioxide without producing ATP or sugar
-may be evolutionary relic; when rubisco evolved atmosphere had less oxygen, more cardon dioxide
-limits damaging products of light reactions that build up in absence of Calvin cycle
-can be problematic; on hot dry day it can drain up to 50% of the carbon fixed by Calvin cycle |
|
|
Term
| Alternate modes of carbon fixation |
|
Definition
evolved to survive hot, dry climates
minimize photorespiration
optimize Calvin cycle even in hot, dry climate
C4 photosynthesis |
|
|
Term
|
Definition
open stomata at night, incorporate carbon dioxide into organic acids; during day carbon dioxide released from organic acids for use in Calvin cycle (light reactions need light from the day)
-succulents, cacti, pineapples, etc. |
|
|
