Biology - 2.1

  • Created by: TobyHill5
  • Created on: 04-04-18 15:53
What are the benefits of Light Microscopes?
cheap, easy to use, portable, able to study WHOLE LIVING ORGANISMS
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How do electron microscopes work?
they use a beam of fast travelling electrons with a wavelength of 0.004nm. (1)electrons are fired from a cathode and focused by magnets. (2) fast travelling electrons have a wavelength 125,000 times smaller than visible light (400-700nm)
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Drawbacks of electron microscopes?
large and very expensive. require skill and training to use
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How to go from metres (m) to pica-metres (pm)
m x100 = cm x10 = mm x1000 = um x1000 = nm x1000 = pm
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Must-Dos for Biological Drawings
at least 50% of paper, single continuous label lines used, ruled label lines (horizontal, no arrows) , main structures are labelled, title, accurate representation, sharp pencil, annotation about colour, magnification
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How to calibrate an eyepiece graticule using the stage micrometer
(1) Align the EPG and the SM (2) record how many EPG divisions are the same value as the whole SM (3) Divide 1000um by the no of divisions, to give how many micrometres (um) is measured by 1 division on the EPG
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How do Transmission Electron Microscopes work?
(1) the specimen is chemically fixed by being dehydrated and stained with metal salts. (2) the beam of electrons PASSES THROUGH the specimen and then focused on a screen
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How do Scanning Electron Microscopes work?
(1) the specimen is placed in a vacuum and coated in a fine film of metal (2) the electrons do not pass through the specimen, but cause secondary electrons to bounce off of the specimen
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The Structure of the Nucleus, Nuclear Envelope + Nucleolus
(1) double membrane (2) nucleolus has no membrane, is filled with RNA (3) the genetic material is chromatin, containing DNA wound around histone proteins
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Function of Nucleus, Nuclear Envelope + Nucleolus
(1) nuclear envelope separates contents from rest of cell (2) pores enable large substances, rRNA, to enter and leave (3) nucleolus is where ribosomes are made (4) chromosomes contain the genome
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Structure of RER
(1) system of membranes containing fluid filled CISTERNAE, continuous with nuclear membranes (2) coated in ribosomes
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Function of RER
(1) the intracellular transport system - cisternae form channels (2) provides large surface area for ribosomes, which pass through membrane, into cisternae, and out to the golgi apparatus
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Structure of SER
(1) a system of membranes containing cisternae that are continuous with the nuclear membrane (2) no ribosomes
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Function of SER
(1) contains enzymes involved with lipid metabolism and the synthesis of cholesterol/lipids/phospholipids/steroid hormones (2) involved in absorption, synthesis and transport of lipids
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Structure of Golgi Apparatus
(1) a stack of membrane bound flattened sacs (2) secretory vesicles bring material to and from
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Function of Golgi Apparatus
(1) MODIFIES proteins by adding sugar molecules to make glycoproteins, adding lipid molecules to make lipoproteins, fold proteins into 3D shape. (2) PACKAGES proteins into vesicles that are either stored or excreted from cell
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Structure of Chloroplasts
(1) double membrane (2) inner membrane is continuous with stacks of flattened membrane sacs called THYLAKOIDS (3) each stack called a GRANUM and contains a fluid filled matrix called the STROMA (4) they contain loops of DNA + starch grains
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Function of Chloroplasts
(1) the site of photosynthesis (2) light energy is trapped by chlorophyll and used to make ATP, happens in the grona. water is made into H+ ions (3) hydrogen reduces CO2 using ATP to make carbs, happens in STROMA
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Structure of Mitochondria
(1) surrounded by 2 membranes with a fluid filled CISTERNAE. (2) inner membrane is highly folded into CRISTAE (3) inner part of mitochondrion is a fluid filled matrix
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Function of Mitochondria
(1) site of ATP production using aerobic respiration (2) self-replicating ~ more produced if energy need increases (3) abundant in very metabolically active cells
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Structure of Vacuole
(1) surrounded by membrane celled TONOPLAST (2) contains fluid
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Function of Vacuole
(1) filled with water and solutes and maintains cell stability (2) when full it pushes against cell wall, making the cell turgid (3) if all cells turgid, this supports the plant
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Structure of Lysosomes
(1) small bags formed from golgi apparatus, each surrounded by single membrane (2) contains powerful hydrolytic enzymes (3) abundant in phagocytic cells that ingest + digest pathogens
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Function of Lysosomes
(1) keep powerful enzymes separate from rest of cell (2) can engulf old cell organelles and foreign matter, digest it, and return the components for reuse
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Structure of Cilia and Undulipodia
(1) protrusions from the cell surrounded by the plasma membrane (2) each contain microtubules (3) form from centrioles
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Function of Cilia and Undulipodia
(1) cilia used to move mucus in epithelial cells (2) all cells have one cilium acting as an antenna - it contains receptors and detects changes (3) spermatozoon has big undulipodium
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Structure of Ribosomes
(1) made of RNA (2) made in nucleolus in 2 subunits, pass out into cytoplasm then combine (3) some float free, most sit on RER
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Function of Ribosomes
(1) ribosomes on RER used for synthesising proteins that are transported out of the cell (2) ribosomes in cytoplams are site for synthesising proteins for use inside the cell
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Structure of Centrioles
(1) consists of 2 bundles of microtubules at RIGHT ANGLES to each other (2) microtubules are made of the tubulin protein subunit and are arranged to form a cylinder
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Function of Centrioles
(1) spindle in cell division is made her (2) motor proteins walk along the centrioles, pulling chromosomes to one side (3) involved in the formation of cilia+undulipodia
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Structure of Cytoskeleton
(1) a network of protein structures (2) rod-like microfilaments are made from the protein actin (3) straight cylindrical microtubules are made from tubulin (4) the cytoskeletal motor proteins are molecular motors.
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Function of Cytoskeleton
(1) protein microfilaments give support and strength. maintain cell shape (2) microtubules provide shape + support. they form the track that motor proteins walk along, transporting organelles. form the spindle before the cell divides. make cilia
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Structure of Cellulose Cell Wall
(1) on outside of the plasma membrane (2) made from cellulose fibres
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Function of Cellulose Cell Wall
(1) strong, prevent bursting when turgid. strength. support, maintain shape. permeable
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Features of Prokaryotic Cells
(1) PILI - small, hair like structures allowing bacteria to adhere to host cells. (2) NUCLEOID - area in cytoplasm where DNA is positioned. (3) Cell wall is made from PEPTIDOGLYCAN. (4) they have a waxy, protective cuticle (5) plasmids (6) FLAGELLA
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All eukaryotic cells have......
(1) a nucleus surrounded by nuclear envelope (2) a nucleolus containing RNA (3) jelly cytoplasm (4) cytoskeleton (5) plasma membrane (6) vesicles (7) ribosomes
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Prokaryote v Eukaryote ; Similarities
plasma membrane, cytoplasm, ribosomes, DNA, RNA
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Prokaryote v Eukaryote ; Differences
Prokaryotes are/have: smaller, less developed cytoskeleton (no centrioles), no nucleus, no membrane bound organelles, peptidoglycan cell wall, protective waxy cuticle, flagella, divide by binary fission, smaller ribosomes, DNA in plasmid, pili
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(1) gene is transcribed onto length of mRNA + copies made (2) mRNA passes out nuclear pores into ribosomes (3) protein synthesised (4) protein passes into cisternae of RER (5) vesicle pinched off from RER and pass via microtubules to the Golgi
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(6) Vesicle fuses with golgi apparatus, protein modified or repackaged (7) new protein in vesicle again, moves to plasma membrane (8) vesicle fuses via exocytosis and protein is secreted
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Card 2


How do electron microscopes work?


they use a beam of fast travelling electrons with a wavelength of 0.004nm. (1)electrons are fired from a cathode and focused by magnets. (2) fast travelling electrons have a wavelength 125,000 times smaller than visible light (400-700nm)

Card 3


Drawbacks of electron microscopes?


Preview of the front of card 3

Card 4


How to go from metres (m) to pica-metres (pm)


Preview of the front of card 4

Card 5


Must-Dos for Biological Drawings


Preview of the front of card 5
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