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76 Cards in this Set
- Front
- Back
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photosynthesis
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plants capture light energy from sun and convert it to chemical energy stored in sugar and other organic molecules
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autotrophs
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"self-feeders", sustain themselves without eating anything derived from other living beings
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heterotrophs
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obtain organic material by second major mode of nutrition
-live on compounds by other organisms |
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photoautotrophs
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organisms use light energy to drive the synthesis or organic molecules from carbon dioxide and normally water
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chlorophyll
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green pigment located within chlorplasts
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mesophyll
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where chloroplasts normally are found is the tissue in the interior of the leaf
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stomata
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microscopic pores. where carbon dioxide enters and oxygen exits
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stroma
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dense fluid within the chloroplast
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thylakoids
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elaborate system of interconnected membranous sacs, segregate stroma from thylakoid space
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the splitting of water
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-oxygen given off from plants derived from water not carbon dioxide
-oxygen released to atmosphere -hydrogen taken from water is formed into sugar to be waste product |
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cellular respiration
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energy released from sugar when electrons associated with hydrogen are transported by cariers to oxygen, forming water as a by product electrons lose potential energy-->down electron transport chain
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photosynthesis
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water is split, electrons transfer along with hydrogen from water to carbon dioxide, reducing it to sugar because electrons increase in potential energy move from water to sugar, process requires energy-->endergonic(energy boost provided by light)
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light reactions
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steps of photosynthesis that convert solar energy to chemical energy
-light absorbed by chlorophyll(drives a transfer of electrons and hydrogen from water to acceptor NADP+ -use solar power to reduce NADP+-->NADPH |
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calvin cycle
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light independent rxn
-carbon fixation=incorporating carbon dioxide from air into organic molecules in chloroplast -reduces fixed carbon-->carbohydrate by adding electrons:reducing powered by NADPH -to convert carbon dioxide goes to carbohydrate ATP needed and by light rxns |
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cell division
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reproduction of cells
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cell cycle
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life of a cell from time it is formed from a dividing parent cell until its own division into two cells
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genome
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genetic info "cell's endowment of DNA"
prokaryotic:normally single long DNA molecule eukaryotic:enormous length of DNA |
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chromosomes
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packages of DNA molecules
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somatic cells
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46 chromosomes=23 pairs
all body cells except reproductive cells |
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gametes
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sperm and eggs, reproductive cells
half as many as somatic chromosomes=23 total chromosomes |
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chromatin
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a complex of DNA and associated protein molecules that make up eukaryotic chromsomes
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sister chromatids
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two chromatids each containing an identical DNA molecule
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cohesins
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initially attach sister chromatids along lengths with these protein complexes
-attachment=sister chromatid cohesion |
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centromere
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specialised region where two chromatids are most closely attached
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arm of chromatid
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either side of centromere
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mitosis
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division of the nucleus
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cytokinesis
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division of the cytoplasm
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chromosome duplication and distribution during cell division
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1.before duplication each chromosome has a single DNA molecule
2.Once replicated a chromosome consists of 2 sister chromatids connected along their entire lengths by sister chromatids cohesion. each chromatid contains copy of DNA molecule 3.seperate sister chromatids into 2 chromosomes and distribute them to two daughter cells |
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meiosis
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(produce gametes):yields nonidentical daughter cells that have only one set of chromosomes
-half as many chromosomes as parent cell, occurs only in gonads |
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fertilization
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fuses two gametes together and returns the chromosome number 46
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mitotic (M) phase
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includes both mitosis and cytokinesis usually shortest part of the cell cycle
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interphase
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accounts for around 90% of cycle. cell grows and copies chromosomes in preparation for cell division
-G1, S, G2 phase |
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G1 phase
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cell grows by producing proteins and cytoplasmic organelles such as mitochondrian and ER
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S phase
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continues to grow as copies chromosomes
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G2 phase
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grows more as completes preparatory for cell division
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G2 of interphase (elongated def)
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-nuclear envelope bounds nucleus
-nucleus contains 1 and nucleoli -two centrosomes have formed by replication of single centrosome |
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prophase
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-chromatin fibers are more tightly coiled-->condense into discrete chromosomes(can see with light microscope)
-nucleoli disappear -duplicated chromosome appear as two identical sister chromatids, joined together @ centrosomes and by cohesins -mitotic spindle beings to form -asters -centrosomes move away from eachother (propelled by lengthening microtubules btwn them) |
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mitotic spindle
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composed of centrosomes and microtubules extend from them
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asters
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radial arrays of shorter microtubules that extend from centrosomes
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prometaphase
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-nuclear envelope fragments
-microtubules invade nuclear area -chromosomes more condensed -each of two chromatids of each chromosome now has kinetochore -kinetochore microtubules form and jerk chromosomes back and forth |
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kinetochore
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specialized protein structure located at centromere
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nonkinetochore microtubules
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interact with opposite pole microtubules of spindle
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metapahse
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-longest stage of mitosis ~20min.
-centrosomes at opposite poles of cell -chromosomes centromeslie on metapahse plate when they convene -each chromosome, kentochores of sister chromatids are attached to kinetochore microtubules from opposite poles |
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metaphase plate
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imaginary plane that is equidistant btwn spindle's two poles
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anaphase
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-shortest stage of mitosis~few minutes
-begins when cohesin proteins are cleaved(seperated) -->allows sister chromatids of each pair to part suddenly. each chromatid becomes a chromosome -microtubules shorten so two daughter chromosomes move toward opposite ends, (attached at centromere so centromere moves first) -cell elongates as nonkinetochore microtubules lengthen -at end, two ends of cell have equivalent complete collections of chromosomes |
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telophase
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-two daughter nucleu form in cell
-nuclear envelopes arise from fragments of parent cells and other portions of endomembrane system -nucleoli reappear -chromosomes become less condensed -mitosis, division of one nucleus into two genetically identical nuclei is complete |
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mitotic spindle
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begins to from in cytoplasm during prophase. structure consists of fibers made of microtubules and associated proteins
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centrosome
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microtubule organizing center:subcellular region containing material that functions throughout the cell cycle to organize cell's microtubules
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cleavage
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process that allows cytokinesis
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cleavage furrow
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a shallow groove in cell surface near old metaphase plate
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cell plate
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in plant cells instead of cleavage furrow
vesicles derived from Golgi move along microtubules to middle cell and coalese -enlarges until fuses with plasma membrane |
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binary fission
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asexual reproduction of single-celled eukaryotes
"division in half" |
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origin of replication
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specific place on chromosome that when bacterial chromosome begin to replicate here (DNA) initiates cell division
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possible intermediate stages
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dinoflagellates and diatoms/yeasts
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bacteria mitosis
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daughter chromosomes move to opposite ends of cell. proteins may anchor daughter chromosomes to specific sites on plasma membrane
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dinoflagellates mitosis
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unicellular protists, chromosomes attach to nuclear envelope, which remains intact during cell division. microtubules pass through nucleus into cytoplasmic tunnels, reinforces spatial orientation of nucleus
-->divides in process close to bacterial binary fission |
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diatoms and yiests mitosis
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unicellular protists, nuclear envelope remains intact, microtubules form spindle within nucleus seperate chromosomes and nucleus splits into two daughter nuclei
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evidence for cytoplasmic signals
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-cell cycle driven by specific signaling molecules present in cytoplasm
-when a cell is fused with another cell in a state farther along in mitosis or interphase it will automatically reach that stage (whether prepared or not) |
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cell cycle control system
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cyclically operating set of molecules in the cell that both triggers and coordinates key events in cell cycle
-regulated at certain checkpoints by both internal and external signals |
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checkpoint
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control point where stop and go ahead signals can regulate the cycle
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three major checkpoints
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G1, G2, M phases
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G1 checkpoint
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"restriction point" most important. if cell recieves go-ahead signal will usually complete next all phases and divide
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G0
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nondividing state
-mature nerve and muscle cells never divide |
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protein kinases
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enzymes that activate or inactivate other proteins by phosphorylation
-to be active have to be attached to cyclin |
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cyclin
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protein that gets name from cyclically fluctuating concentration in cell
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MPF
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acts at G2 checkpoint as go-ahead signal
-maturation-promoting factor -acts directly and indirectly by activating other kinases -during anaphase switches off -peaks during metaphase |
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m phase checkpoint
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anaphase, seperation of sister chromatids, does no occur until all chromosomes are properly attached to the spindle at metaphase plate
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growth factor
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protein released by certain cells that stimulate other cells to divide
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platelet-derived frowth factor
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required for division of fibroblasts in culture
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density-dependent inhibition
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crowded cells stop dividing
-normally divides until single layer than stops |
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anchorage dependence
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to divide must be attached to a substration
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cancer cells
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-don't heed normal signals that regulate cell cycle
-divide excessivly and can invade other tissues -lack of density-dependent inhibition and anchorage dependence -stop dividing at random points |
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transformation
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process that converts a normal cell to a cancer cell
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benign tumor
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mass of abnormal cells within otherwise normal tissue, abnormal cells remain at original site
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malignant tumor
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becomes invasive enough to impair functions of one or more organs
-excessive proliferation -can have unusual number of chromosomes -metabolism may be dissolved -may cease to function in any constructive way |
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metastasis
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spread of cancer cells to locations distant from original site
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