CSET 2: Science Summary

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CSET 2: Science Summary
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CSET 2: Science Summary
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  1. Mollusca Phylum
    abalone, sea snail, oyster

    Etymology:- From the Latin Molluscus meaning soft of body.

    • Characteristics of Mollusca:-
    • 1)Bilaterally symmetrical.
    • 2)Body has more than two cell layers, tissues and organs.
    • 3)Body without cavity.
    • 4)Body possesses a through gut with mouth and anus.
    • 5)Body monomeric and highly variable in form, may possess a dorsal or lateral shells of protein and calcareous spicules.
    • 6)Has a nervous system with a circum-oesophagal ring, ganglia and paired nerve chords.
    • 7)Has an open circulatory system with a heart and an aorta.
    • 8)Has gaseous exchange organs called ctenidial gills.
    • 9)Has a pair of kidneys.
    • 10)Reproduction normally sexual and gonochoristic.
    • 11)Feed a wide range of material.
    • 12)Live in most environments.
  2. Echinoderm
    Sea urchin

    living only in the sea - never in freshwater, the ability to regenerate and tube feet
  3. ph scale
    • acid <7
    • base >7
  4. Biological Molecules
    Carbohydrates (aka sugars)
    • _role: energy metabolism/storage, structure of the cell/organisms
    • _composed: carbon, hydrogen, oxygen
  5. Biological Molecules
    Lipids
    • _role: energy metabolism/storage, cellular membranes
    • _composed: carbon, hydrogen, oxygen
    • _lower oxygen content than carbs
    • _less oxidized, storing more energy than carbs
  6. Biological Molecules
    Proteins
    • _polymers formed by joining simple building blocks called amino acids together in a process called translation
    • _role: provide cells w/ the ability to carry out a broad range of functions
  7. Biological Molecules
    Enzyme
    • _role: biological catalysts to speed up chemical reactions and make them useful for living organisms
    • _composed: almost all are proteins
    • _any biological molecule that can catalyze a reaction is an enzyme
  8. Biological Molecules
    Nucleic acids
    • _polymers formed by joining together specific monomers called nucleotides (ATP - created when organism eats carbs + fats that contain chemical energy + digests these moelecules to trap their chemical energy); ATP used on cells to do most activities that require energy input
    • _role: informational molecules (DNA/RNA)
  9. photosynthesis
    • _occurs in plants in the chloroplast (an organelle that is specific to plants)
    • _chloroplasts found mainly in the cells of mesophyl (green tissue in the interior of the leaf)
    • _stomata: pores on the surface of leaves that allow carbon dioxide in + oxygen out
    • _chloroplast: inner + outer membrane; w/in the inner membrane the stroma fluid
    • _thylakoid membrane: a series of membranes (forms stacks of grana) in the interior of the chloroplast contains
  10. DNA/RNA
    • DNA
    • _genetic material; responsible for physical traits (phenotype) observed in all living organisms
    • _replicate from existing DNA to produce new genomes
    • _built from nucleotides (adenine, guanine, thymine, cytosine); each has 3 parts (5-carbon sugar [deoxyribose], phosphate grp, nitrogenous base)
    • _form by: nucleotides join together in long regular strands of nucleotide building blocks

    • RNA
    • _role: message used to decode + transmit the genetic info + synthesize proteins according to the encoded info
    • _transcription: process of reading DNA to produce RNA
    • _translation: process of protein synthesis
  11. DNA unique features
    • _double-stranded (except when replicating)
    • _deoxyribose sugar in the nucleotides_thymine base forms a thymine-adenine base pair (T-A)
    • _replicates DNA -> DNA_only 1 type of DNA per organism (original source of info; its info is copied onto RNA molecules)
  12. RNA unique features
    • _nearly always single-stranded
    • _ribose sugar in nucleotides
    • _uracil base instead of thymine; base pair is uracil-adenine (U-A)
    • _does not normally replicate (except in some viruses)
    • _3 types: mRNA, tRNA, rRNA
  13. Cells
    Prokaryotic
    • _bacteria + cyanobacteria (unicellular organisms w/ simple cell structure)
    • _comprised of:outer lipid bilayer cell membrane, do not contain any membrane organelles
    • _have no true nucleus
    • _genetic material: single circular molecule of DNA (nucleoid region)
    • _may also contain plasmids (small circular extachromasomal DNA containing few genes; replicate independently that allows prokaryotes to survive adverse conditions)
    • _form: cell wall, cell membrane, cytoplasm, ribosomes, flagella (sometimes)
    • _respiration: in cell membrane

    • _nucleus: no
    • _genetic material: dna
    • _cell wall: yes
    • _cell membrane: yes
    • _membrane organelle: no
    • _ribosomes: yes (smaller + have different subunit composition than EC)
  14. Cells
    Eukaryotic (EC)
    • _all multicellular organisms (humans, tree, mushroom, etc.) + all unicellular protists (amoeba/paramecia) are composed of Eukaryotic cells (EC)
    • _EC enclosed w/in lipid bilayer cell membrane (like prokaryotic cells)
    • _EC contain organelles (unlike prokaryotic cells)

    • _nucleus: yes
    • _genetic material: DNA
    • _cell wall: yes/no
    • _cell membrane: yes
    • _membrane organelle: yes
    • _ribosomes: yes
  15. Cells
    Plasma Membrane (aka cell membrane)
    • _encloses the cell + exhibits selective permeability
    • _regulates passage of materials into + out of the cell
  16. Cells
    Organelle
    specialized part of a cell having some specific function; a cell organ.

    _membrane-bound structures w/in cell w/ specific functions isolated in separate compartments

    _include nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, microbodies, vacuoles, mitochondria, chloroplasts

    _separation of the organelle membrane and interior from the rest of the cell allows organelles to perform distinct functions isolated from other activities

    _the separation of the organelle membrane prevents incompatible processes from mixing together; allows step-wise processes to be more strictly regulated; can make more processes more efficient by making them happen in a single constrained place

    _Cytoplasm: liquid inside the cell surrounding organelles
  17. Cells: organelle
    Nucleus
    • _where genes in DNA are read to produce messenger RNA (transcription), mRNA is spliced, DNA genome is replicated when the cell divides
    • _contains DNA genome complexed w/ proteins (histones) involved in packaging DNA + regulating access to genes
    • _surrounded by 2-layer nuclear membrane that maintains a nuclear environment distinct from that of the cytoplasm
    • _nuclear pores in this membrane allow selective 2-way exchange of materials between nucleus + cytoplasm, importing some proteins into the nucleus that are involved in transcription, mRNA splicing, DNA replication, keeping out other factors like glycolysis + translation
    • _nucleolus: dense structure w/in nucleus in which ribosomal RNA (rRNA) synthesis occurs
  18. Cell: organelle
    Ribosomes
    • _large complex structures that are the sites of protein production + are synthesized by the nucleolus
    • _2 units: 1 large, 1 small; composed of rRNA + many proteins
    • _free ribosomes are found in the cytoplasm
    • _bound ribosomes line the outer membrane of the endoplasmic reticulum
  19. Cell: organelle
    Endoplasmic Reticulum (ER)
    • _network of membrane-enclosed spaces connected at points w/ nuclear membrane
    • _network extends in sheets + tubes thru cytoplasm
    • _rough endoplasmic reticulum (RER): the network has ribosomes lining its outer surface
    • _smooth endoplasmic reticulum (SER): w/out ribosomes
    • _ER transports proteins in cells, esp proteins destined to be secreted from the cell
    • _SER - lipid synthesis, detox of drugs/poisons
    • _RER - protein synthesis
  20. Cell: organelle
    Gogi apparatus
    • _stack of membrane-enclosed sacs
    • _active in distribution of newly synthesized material to the cell surface (in cells active in secretion of proteins)
    • _(1)receives vesicles + their contents from ER + modifies proteins
    • _(2)repackages them into vesicles + ships the vesicles to the next stop (lysosomes/plasma membrane)
  21. Cell: organelle
    lysosomes
    • _contain hydrolytic enzymes involved in intracellular disgestion, degrading proteins + structures that are worn out or not in use
    • _max effective at ph of 5, hydrolytic enzymes enclosed w/in the lysosome (acidic environment distinct from the neutral pH of the cytosol - fluid portion of the cytoplasm)
    • _fuse w/ endocytic vacuoles, breaking down material ingested by the cells
    • _aid in renewing cell's own components by breaking them down + releasing their molecular blocks into the cytosol for reuse
  22. Cell: organelle
    microbodies
    • _specialized containers for metabolic reactions
    • _types: peroxisomes, glyoxysomes
    • _peroxisomes: contain oxidative enzyme that catalyze a class of reactions in which hydrogen peroxide is produced thru the transfer of hydrogen from a substrate to oxygen
    • _peroxisomes:break fats down into small molecutes that can be used for fuel; used in liver to detoxify compounds (alcohol)

    • _glyoxysomes: found in the fat tissue of germinating seedlings
    • _glyoxysomes: used by the seedling to convert fats into sugars until the seedling is mature enough to produce its own supply of sugars through photosynthesis
  23. Cell: organelle
    vacuoles
    • _membrane-enclosed sacs w/in cell
    • _formed after endocytosis + can fuse w/ a lysosome to digest their contents
    • _contractile vacuoles in freshwater protists pump excess water of out the cell.
    • _Tonoplast: part of plant's endomembrane system, large central vacuole; functions as a place to store organic compounds (proteins), inorganic ions (potassium, chloride); wastes can be stored here
  24. Cell: organelle
    mitochondria
    • _sites of aerobic respiration w/in the cell + are important suppliers of energy
    • _membrane-enclosed organelle found in most eukaryotic cells.
    • _has an outer/inner membrane
    • _outer membrane: many pores, acts a a sieve, allowing molecules thru the basis of their size
    • _inner membrane: many convolutions called cristae + high protein content that includes the proteins of the electron transport chain
    • _mitrochondrial matrix: area bounded by the inner membrane; site of many of the reactions in cell respiration
    • _contain their own circular DNA and ribosomes which enable them to produce some of their own proteins + to self-replicate through binary fision
    • _These organelles range from 0.5 to 1.0 micrometer (μm) in diameter.
    • _sometimes described as "cellular power plants" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy.
    • _In addition to supplying cellular energy, mitochondria are involved in other tasks such as signaling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth.
    • _The word mitochondrion comes from the Greek μίτος mitos, thread, + χονδρίον chondrion, granule
  25. Cell: organelle
    chloroplasts
    • _found only in algal + plant cells
    • _function as the site of photosynthesis w/ the help of chlorophyll
    • _contain their own DNA + ribosomes exhibit the same semiautonomy as mitochondria
  26. Cell: organelle
    cytoskeleton
    • _helps the cell gains mechanical support, maintains its shape + carries out cell motility functions 
    • _composed of microtubules, microfilaments, intermediate fibers, and chains + rods of proteins each w/ distinct functions + activities
  27. Cell: organelle
    microtubules
    • _hollow rods made of proteins
    • _when polymerized, they radiate throughout the cells + provide it w/ support  + framework for organelle movement w/in the cell
    • _centrioles + mitotic spindle (direct the separation of chromosomes during cell division) are composed of microtubules
  28. Cell: organelle
    cilia and flagella
    • _specialized arrangements of microtubules that extend from certain cells + involved in cell mobility
    • _prokaryotic flagella are structured very differently than eukaryotic flagella
  29. Cell: organelle
    microfilaments
    • _solid rods composed of actin subunits
    • _partly maintains cell movement + support (ex: muscle contraction is based on the interaction of actin + myosin in muscle cells)
    • _move materials across the plasma membrane
    • _active (ex: in the contraction phase of cell division + in amoeboid movement)
  30. Cell: organelle
    intermediate fibers
    • _collection of fibers involved in the maintenance of cytoskeletal integrity
    • _diameters fall between microtubules + microfilaments
  31. Cell: Membrane transport across the plasma
    permeability - diffusion thru the membrane
    • _membrane is selectively permeable
    • _sum total of movement across the membrane is determined by passive diffusion of material directly thru the membrane + selective transport processes thru the membrane that requires proteins
  32. Cell: Membrane transport across the plasma
    transport proteins
    • _molecules that do not diffuse thru the membrane can often get in/out of the cell w/ the aid of proteins in the membrane
    • _3 types: uniport, symport, antiport
    • _uniport: carry a single solute across the membrane
    • _symport: translocate 2 different solutes simultaneously in the same direction
    • _antiport: exchange 2 solutes by transporting 1 into the cell, other out of the cell
  33. Cell: Membrane transport across the plasma
    diffusion/passive transport
    • _diffusion: net movement of dissolved particles down their concentration gradients, from a region of higher concentration to a lower concentration region
    • _passive diffusion: does not require proteins since it occurs directly thru the membrane
    • _since molecules are moving down a concentration gradient, no external energy is required
  34. Cell: Membrane transport across the plasma
    facilitated diffusion
    • _net movement of dissolved particles down their concentration gradient with the help of carrier proteins in the membrane
    • _does not require external energy
    • _ex: ion channels creates a passage for ions to flow thru the membrane down their concentration gradient
  35. Cell: Membrane transport across the plasma
    active transport
    • _net movement of dissolved particles against their concentration gradient with the help of transport proteins _requires external energy
    • _necessary to maintain membrane potentials in specialized cells such as neurons
    • _common forms of energy to drive active transport: ATP, concentration gradient of another molecule
    • _used for uptake of nutrients against a gradient
  36. Cell: Membrane transport across the plasma
    osmosis
    • _simple diffusion of water from a lower solute concentration region to a higher concentration region
    • _water flows to equalize the solute concentrations
    • _if a membrane is impermeable to a particular solute, then water will flow across the membrane until the differences in the solute concentration have been equilibrated
    • _differences in the concentration of substances to which the membrane is impermeable affect the direction of osmosis
  37. Cell: endocytosis/exocytosis
    • _endocytosis: process in which the cell membrane forms a vesicle that contains extracellular material
    • _pinocytosis: ingestion of liquids or small particles
    • _phagocytosis: engulfing of large particles
    • _exocytosis: occurs when a vesicle w/ the cell fuses w/ the cell membrane + releases its contents to the outside (plays an important role in cell growth + intercellular signaling)
  38. Viruses
    • _small packages of nucleic acid in a protein coat that replicate themselves in cells
    • _not cells (have no cytoplasm, carry out no biochemical activity of their own)
    • _dependent on living w/in a cell to carry out metabolic processes + replicate
    • _not generally considered to be living organisms
    • _possess characteristics of life only when they've infected a  living host cell
  39. Reproduction
    • _eukaryotes: occur as asexual or sexual production
    • _prokaryotes: binary fission
  40. Reproduction
    Mechanisms of Cell Division
    • _Binary fission: prokaryotic cells divide + reproduce themselves
    • _Mitosis + meiosis: process of how eukaryotes cells divide
    • _Mitosis: cells divide to produce 2 daughter cells w/ the same genomic complement as the parent cell (humans - 2 copies of the genome in each cell); can be a means of asexual production; mechanism for growth, development, replacement of tissue
    • _Meiosis: specialized form of cell division involved in sexual reproduction that produces male + female gametes (sperm + ova); creates cell w/ a single copy of the genome in preparation for sexual reproduction in which gametes join to create a new organism w/ 2 copies of the genome (1 from each parent)
  41. Reproduction
    Prokaryotic Cell Division + Reproduction
    • _DNA replication: have no organelles + 1 chromosome in a single long circular DNA; chromosome is attached to a cell membrane + replicated as cell grows
    • _after DNA replication, 2 copies of the genome is attached to the cell membrane, DNA drawn apart from each other as the cell grows in size + adds more membrane between the DNA
    • _when the cell is big as 2 cells, cell wall and membrane close off to create 2 independent cells
    • _can reproduce and divide as rapid as 30 min under ideal conditions
    • _conjugation: used by bacteria to move genes between cells by exchanging a circular extrachromosomal DNA w/ each other
    • _transduction: viruses infecting bacteria can accidentally carry the bacterial genes w/ them into a new cell that they infect; can introduce new genes into bacteria
  42. Reproduction
    Mitosis
    • _cells divide to produce 2 daughter cells w/ the same genome as the parent cell
    • _cell cycle: growth + division of cells to make new cells; linked to growth + differentiation of tissues; failure to control the cycle properly can result in uncontrolled progression thru the cycle + cancer
    • _cancer cells contain mutations in genes that regulate the cell cycle
    • _four stages: G1, S, G2, M
    • _interphase stages (occur between the cell division): G1, S, G2
    • _mitosis: M (actual division of the cell)
  43. Reproduction
    Stage G1, S, G2, M(mitosis)
    • _Stage G1:intense biochemical + biosynthetic activity + growth; cell doubles in size + new organelles (mitochrondria, ribosomes, centrioles) produced
    • _Stage S: synthesis of DNA; complete copy of genome can be distributed to both daughter cells; chromosomes consist of 2 identical sister (chromatids) held together by central region (centromere); ends of chromosomes (telomeres);
    • _Stage G2: cell prepares for mitosis, making any of the components still needed to complete cell division
    • _Stage M:cell divides to create 2 similar but smaller daughter cells
  44. Reproduction
    Asexual reproduction
    • _method of producing new organisms in which fusion of nuclei from 2 individuals (fertilization) does not take place
    • _1 parent organism is involved
    • _form daughter cells thru mitotic cell division + are genetically identical, clones of their parents
    • _purpose: allows primitive organisms + plants to produce (esp low pop. density); does not create the genetic diversity but allows for rapid growth
    • _not common in animals
    • _parthenogenesis + regeneration: major types asexual reproduction found in animals
    • _parethenogenesis: egg develops in absence of fertilization by sperm thru mitotic cell division (bees); artificial parethenogenesis can be performed in some animals (rabbits, frogs)
    • _regeneration: ability of certain animals to regrow a missing body part; sometimes parts of an animal grow into a complete animal - resulting in reproduction (flatworm, earthworm, lobster, sea star)

    • binary fission: prokaryotes, algae, bacteria
    • _single DNA molecule attaches to a plasma membrane during replication + duplication, while the cell continues to grow in size
    • _results in daughter cell receiving complete copy of original parent's cell's chromosomes

    • Budding: mitotic asexual reproduction; _unequal division of cytoplasm (cytokinesis) between the 2 daughter cells + equal division of the nucleus (karokinesis)
    • _parent cell forms smaller daughter cell that sprouts off w/ less cytoplasm than the parent
    • _daughter organism becomes independent + is released
    • _common in unicellular organisms (yeast)
    • _occurs in some mulitcellular organisms (hydra)
  45. Reproduction
    Sexual reproduction
    • _involves the union of haploid cell from 2 different parents to produce diploid offspring
    • _haploid cells are the gametes (sex cells produced thru meiosis in males + females)
    • _gametes: single copy of the genome (1 from each chromosome) + diploid cells have 2 copies of the genome (2 from each chromosome)
    • _humans: all of the cells of the body are diploid w/ exception of the gametes; male gamete and the female gamete (sperm + egg) join, zygote is formed that develops into a new organism genetically distinct from its parents (zygote is diploid single cell offspring formed from the union of the gametes)
  46. Gamete formation
    • _gonads: produce gametes thru meiotic cell division
    • _male gonads (testes): spermatozoa
    • _female gonads (ovaries): ova

    • Germ cell: cell that is committed to production of gametes (not itself a gamete); rest of the body called somatic cell; genome of germ cell contributes to gametes + offspring;
    • _somatic cell mutation may be harmful to the cell/organism if it leads to cancer but will not affect offspring since mutation will not be found in germ cell genome
    • _are diploids + divide to create more germ cells by mitosis
    • _create haploid gametes thru meiosis

    • Meiosis: 2 rounds of cell division, single diploid cell first replicates its genome, divides once into 2 cells each w/ 2 copies of the genome
    • _w/out replicating DNA, 2 cells divide again for 4 haploid gametes
  47. Human male reproductive system
    _

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