IGCSE Biology - Biological Molecules (4.1)

00:04:54
https://www.youtube.com/watch?v=r_IuubI9M6Y

摘要

TLDRVideo käsitleb Cambridge IGCSE bioloogia teemat 4.1, mis keskendub bioloogilistele molekulidele, sealhulgas süsivesikutele, rasvadele, valkudele ja DNA-le. Süsivesikud koosnevad süsinikust, vesinikust ja hapnikust ning jagunevad lihtsateks suhkruks ja polüsahhariidideks. Rasvad, nagu triglütseriidid, on energiat salvestavad molekulid, samas kui valgud koosnevad aminohapetest ja täidavad mitmeid funktsioone, sealhulgas ensüümide ja hormoonide tootmist. Video tutvustab ka viit keemilist testi erinevate molekulide tuvastamiseks ja DNA struktuuri, mis koosneb kahest ahelast, mis on seotud nukleotiidide kaudu.

心得

  • 🧬 Bioloogilised molekulid: süsivesikud, rasvad, valgud, nukleiinhapped
  • 🔗 Polümeerid koosnevad monomeeridest
  • 🍞 Süsivesikud: glükoos, tärklis, tselluloos
  • 💧 Triglütseriidid: energiasalvestusvorm
  • 🔬 Biureti test valkude tuvastamiseks
  • 🧪 Joodi test tärkli tuvastamiseks
  • 🍊 C-vitamiini test: DCPIP ja sidrunimahl
  • 🧪 Rasvade test: emulsioon
  • 🧬 DNA struktuur: topeltspiraal
  • 🔗 Nukleotiidid: deoksüriboos, fosfaadigrupp, alused

时间轴

  • 00:00:00 - 00:04:54

    Selles videos tutvustatakse Cambridge IGCSE bioloogia teemat 4.1, mis käsitleb bioloogilisi molekule. Peamised teemad hõlmavad süsivesikute, rasvade ja valkude keemilisi elemente, nende väiksemate molekulide struktuuri, keemilisi teste erinevate molekulide tuvastamiseks ning DNA molekuli struktuuri. Bioloogilised molekulid jagunevad neljaks peamiseks klassiks: süsivesikud, lipiidid, valgud ja nukleiinhapped, millest igaühel on rakus olulised funktsioonid. Süsivesikud koosnevad süsinikust, vesinikust ja hapnikust ning sisaldavad lihtsaid suhkrute monomeere nagu glükoos, mis moodustavad keerukamaid polüsahhariide nagu tärklis ja tselluloos. Rasvad, sealhulgas triglütseriidid, on samuti süsiniku, vesiniku ja hapniku koostisosad, kuid erinevas proportsioonis. Valkude struktuur koosneb aminohapetest, millest igaühel on oma spetsiifiline järjestus. Videos tutvustatakse ka viit keemilist testi, et tuvastada erinevaid bioloogilisi molekule, sealhulgas tärklise, vähendavate suhkrute, valkude, rasvade ja C-vitamiini testid. Lõpuks käsitletakse DNA struktuuri, mis koosneb kahest pikast ahelast, mis on seotud nukleotiidide kaudu ja moodustavad topeltspiraali.

思维导图

视频问答

  • Millised on peamised bioloogilised molekulid?

    Peamised bioloogilised molekulid on süsivesikud, lipiidid, valgud ja nukleiinhapped.

  • Kuidas tuvastada tärklist?

    Tärkli tuvastamiseks lisage tärklise suspensioonile joodilahust; värv muutub pruunist siniseks.

  • Mis on triglütseriid?

    Triglütseriid on rasvamolekul, mis koosneb kolmest rasvhappest ja ühest glütseroolimolekulist.

  • Kuidas tuvastada valke?

    Valgud tuvastatakse Biureti testiga, kus lahus muutub helesinisest lillaks.

  • Mis on DNA struktuur?

    DNA koosneb kahest pikast ahelast, mis on seotud nukleotiidide kaudu ja moodustavad topeltspiraali.

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  • 00:00:00
    hello and welcome to another complete
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    Cambridge IGCSE biology lesson where
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    you'll learn absolutely everything you
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    need to know on topic 4.1 biological
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    molecules as always we'll be following
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    the Cambridge syllabus exactly and we'll
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    cover absolutely everything you need to
  • 00:00:13
    know if your final exam the topic 4.1
  • 00:00:15
    you need to list the chemical elements
  • 00:00:17
    that make up carbohydrates fats and
  • 00:00:19
    proteins name the smaller molecules that
  • 00:00:22
    larger molecules are made from describe
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    the use of chemical tests for the
  • 00:00:25
    presence of different molecules and for
  • 00:00:27
    extended describe the structure of a DNA
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    molecule there are four major classes of
  • 00:00:32
    biological molecules carbohydrates
  • 00:00:34
    lipids proteins and nucleic acids each
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    is an important component of the cell
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    and performs a wide array of functions
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    carbohydrates fats and proteins are long
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    chains of repeating subunits joined
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    together by chemical bonds chains are
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    called polymers and their subunits are
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    called monomers at a basic level
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    biological molecules are made of
  • 00:00:54
    chemical elements including carbon the
  • 00:00:56
    primary component of all four classes so
  • 00:00:59
    carbohydrates are made of carbon
  • 00:01:00
    hydrogen and oxygen and include simple
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    soluble sugars like the monomer glucose
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    glucose molecules combine to form more
  • 00:01:08
    complex molecules like starch cellulose
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    and glycogen collectively known as the
  • 00:01:12
    polysaccharides glycogen and starch are
  • 00:01:15
    the glucose storage molecules of animal
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    and plant cells they're large branching
  • 00:01:19
    structures mean they're not very soluble
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    in water and therefore cannot pass
  • 00:01:23
    freely through cell membranes cellulose
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    is made of even longer chains of glucose
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    molecules grouped together to form
  • 00:01:29
    layers of microscopic fibers that
  • 00:01:32
    comprise the cell wall in plant cells
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    like carbohydrates fats and oils are
  • 00:01:37
    also made of carbon hydrogen and oxygen
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    although the proportion of each element
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    and the way in which they're arranged
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    are different a molecule of fat called a
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    triglyceride is made up of three fatty
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    acids joined with one molecule of
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    glycerol triglycerides are insoluble in
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    water and therefore function as a
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    storage form of energy in the body fats
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    also form an essential part of cell
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    membranes and the internal membrane
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    lines of cells finally proteins are long
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    chains of smaller subunits called amino
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    acids there are 20 different types of
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    amino acids and each protein has its own
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    specific sequence all amino acids are
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    made of carbon hydrogen oxygen and
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    nitrogen and some contain sulfur and
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    phosphorus as well types of proteins
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    include the enzymes which speed up or
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    catalyze chemical reactions hormones
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    that carry messages in the blood and
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    hemoglobin which transports oxygen
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    proteins also form the major structural
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    components of all cells including cell
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    membranes mitochondria ribosomes and
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    chromosomes next you need to describe
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    five chemical tests that are used to
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    detect the presence of different
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    biological molecules the first is a test
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    for starch mixed starch powder and warm
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    water to make a starch suspension in a
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    test tube and add a few drops of iodine
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    solution in the presence of starch
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    iodine changes color from brown to blue
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    black number two is a test for reducing
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    sugars like glucose and fructose heat
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    equal volumes of glucose solution and
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    Benedict solution in a test tube
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    depending on the amount of sugar in the
  • 00:03:03
    solution the color will change from blue
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    to green to yellow and finally a red
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    deposit of copper oxide number three is
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    the bioret test for protein mix equal
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    volumes of albumin solution which is the
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    protein found in egg white dilute sodium
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    hydroxide and copper sulfate solution in
  • 00:03:19
    the presence of protein the bioret
  • 00:03:21
    reagent changes color from pale blue to
  • 00:03:23
    purple number four is a test for fat mix
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    a couple of drops of cooking oil with
  • 00:03:28
    ethanol in a test tube until the fat
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    dissolves then add a few milliliters of
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    water and observe the formation of a
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    milky white Emulsion finally a test for
  • 00:03:37
    vitamin C place a weak solution of dcpip
  • 00:03:40
    in a test tube and using a syringe add
  • 00:03:42
    fresh lemon juice one drop at a time the
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    blue solution will quickly become
  • 00:03:46
    colorless due to the high vitamin C
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    content of the juice you can repeat the
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    test with orange juice and observe that
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    it takes more drops to decolorize the
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    dye okay so that's everything for the
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    core section but for extended you also
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    need to describe the strap structure of
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    a DNA molecule so DNA or
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    deoxyribonucleic acid is made of two
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    long strands of connected nucleotides
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    that are coiled together to form a shape
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    called a double helix each nucleotide
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    contains a five-carbon sugar molecule
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    called a deoxyribose a phosphate group
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    and an inorganic base there are four
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    different bases adenine thymine cytosine
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    and guanine although you only need to
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    remember the letters a T C and G the two
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    strands of DNA are held together by
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    chemical bonds between the bases and the
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    bases always pair up in the same way a
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    pairs with t and c pairs with G this
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    particular pairing is essential for the
  • 00:04:37
    proper functioning of the molecule well
  • 00:04:39
    done you've just covered absolutely
  • 00:04:40
    everything you need to know on topic 4.1
  • 00:04:42
    biological molecules if you enjoyed this
  • 00:04:44
    video I'd really appreciate your
  • 00:04:46
    subscription and I'll see you next time
  • 00:04:48
    for topic 5.1 enzymes
标签
  • bioloogilised molekulid
  • süsivesikud
  • rasvad
  • valk
  • DNA
  • keemilised testid
  • polümeerid
  • monomeerid
  • ensüümid
  • nukleiinhapped