Biology Unit 1

Does not contain information on neurons

  • Created by: Affreen
  • Created on: 15-05-19 09:05

How to prepare a slide and use a microscope

To prpare a slide

  • First you take a thin layer of the specimen and place it on the center of the using forceps slide.
  • Then using a pipette add 1-2 drops of iodine on the specimen and plce the coverslip over it making sure no air bubbles appear.
  • Finally clip the slide onto the stage of the microscope.

To use a microscope

  • Clip slide
  • then select the lowest objective lens and using the
  • course adjustment knob move the stage closer to the lens so it is visible but not too close.
  • Then finally use the fine adjustment knob to change lenses untill speciment can be seen
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Electron microscopes and Micrographs

Electro microscope

  • Stronger than light as show a detailed picture of specimen clled electron micrographs
  • They have up to  500 00 magnifivation where as light only has 1500 
  • Resolution is 0.1nm whereas for light 200nm and allow us to see subcellular structure (organelles)

 Micrographs

Image result for micrograph of plant cell  Magnification(M) =Size of image(I) / Actual Size (A)

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Eukaryotic (Plant cell)

Multi-celluler organusms that are complex cells with a nucleus and membrane bound organallsMain function is to produce charbohydrates during photosynthesis.

  • Golgi apparatus
  • Mitochondria 
  • Neucleus
  • membrane
  • Smooth ER
  • Rough ER
  • Cell wall-Made from cellouse and protects and supports cell
  • Chloroplast- has a doubble membrane and is the site for photosynthesis
  • Amyloplasts- doubble membrane bound sac that systhesies and stores starch granuels
  • Vacuole
  • Tonoplast membrane- partially permeble membrane for vacuole; allow small molecule to pass
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Eukaryotic (Animal Cell)

 Animal cells synthesise protiens to be used inside the cell for cell multiplication and secretion out of the cell eg, insulin. The ribosomes synthesise the protiens, then those protiens are transported throught the rough ER and packed into vesicles. then they fuse into the Golgi apparatus and the protiens enter it then they get modified and packed into vesicles, trasported to the celll surface membrane and released

  • Cyptoplasm- Where reactions take place
  • Lysome- Vesicles that breack down waste material
  • Rough ER- Ribsomes are attached to it so protien synthesis takes place
  • Vesicle- Transport ones transport material inside cells and secretory transport protiens
  • Golgi Apparatus- new protiens are recived here and modified
  • Plasma Membrane- regulate transport of materials in and out of cell
  • Neucleus-control/regulate cellular activity and cotains genetic material
  • Ribsome- protien synthesis occures here
  • Vacuole- use for storage
  • Centroli- form spindle fibres during cell division
  • Neucleolus- Makes RNA ribosomes
  • Smooth ER- Synthesis and transport of lipids
  • Mitochondria- Site of the final stages of ccellular respiration
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Prokaryotic (Bacteria cell)

A micro-organism that has a simple structure and no neucleus or membrane bound organells. Bacteria creates toxins that can affect other organisms by...

  • Transcription- When a section of DNA containing a genetic code for metabolite unwids and breaks hydrogen bonds then complementary base pairing occures creating RNA
  • Translation- Occures in ribasomes then the created toxins surround surface membrane ready to cause an infection
  • Cell wall- Created by peptidoglycan cells protectand support cell
  • Capsuel- slippery substande surround outside that protects cell
  • Ribsomes- Smaller than usual and protiens are synthesised in this
  • Neucleoid- Irregular shape containing all genetic information and control cellular activity
  • Plasmid- Ring of DNA contaning genes
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Han Christan Gram

He is a Danish microbologist that developed a staining technique to distinguish between groups of bacteria

Gram-Negative bacteria has a thin cell wall and 2 lipid membranes which is why penecillin cannot stop the synthesis of the cell wall of Gram-Negative, but can stop Gram-Positive.

2 stains are addedd to the bacteria; violet and safranin. If puple stain is present then its Gram-Positive bacteria, Pink safranin indicated Gram-Negative (thin cell wall so allow ethonel used during method to wash off crystle violet purple stain) 

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Specialised cells (red and white blood)

Specialisation is the process of when a cell changes its structure to have a certain function (cellular diffrentiation)

Red blood cell (Erythrocytes)- function is to carry oxygen around the body

  • Biconcave shape- Increce surface area to volume ratio
  • Flexible- squeez through narrow blood capilaries
  • No nucleus- increase space for hemaglobin that carry oxygen 

White blood cells (neurophill)- destroy bacteria that enter body

  • Multi-lobed nuclei- squeez through small gaps when travelling to infection site
  • Cyptoplasm hold lysome- contain enzyms that digest pathogens ingested by white blood cell
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Specialised cells (sperm and egg)

Sperm Cell- Male Gamete 

  • Tail- Swimming towards egg
  • Tail contain mitochondria- Supply energy for movement
  • Head made from acrosome containing digestve enzymes- released when sperm meets egg to digest protective layer to allow sperm to penetrate egg

Egg Cell- Female Gamete

  • Anaeucleus- Store getetic information
  • Corona Radiata Attached to zona pellucida- Supply protiens
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Specialised cell plant (root hair+palisade)

Root Hair- Near plant growing tip, hair like extensions

  • Increce surface area- maximise movement of water and minerals from soil
  • Cells have thin cellous walls and vacuole containing cell sap with low water potential- encourages movement of water into cell

Palisade mesophyll cell- found in leaves, move around cyptoplasm to maximise ammount of light absorbed

  • Chloroplast- absorbe large ammount of light for photosynthesis
  • Surrounded by plasma membrane/cell wall- protect cell+keep rigid
  • Large Vacuole- maintain tugor pressure
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Epithelial Tissue

Found in lining of organs and surfaces

Squamous- Ideal for rapid diffusion because the flattened specialised squamous cells that make up the rissue form a smooth flat layer. Line various structures like alvioli in lungs which provide short diffusion pathway to allow rapid diffusion of oxygen into blood.

The cells can be damaged by smoking as it irritates causing inflimmation and scarring the epithelium tissue of lungs. Which will result in the alvioli walls becomming thicker and produce more mucus, causing lungs to loose natural elasticity; breathlessness and persistan coughing.

Ciliated Collmnar- Made up of ciliated cells with hir like structures calle cilia. They line the trachea in the respiratory system to protect the lungs from infection by sweeping pathogens away from the lungs.Goblet cells secrete mucas to help trap unwanted particles present in air you breath. Prevent bacteria reaching alvioli.

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Epithelial Tissue 2

Endothelial

  • layer of flattened tissues
  • Found in the lining of the heart, blood vessels and lymphatic vessels
  • The cells provide a short diffusion path for movement of substances like producs of digestion into blood capillaries and blood plasma + tissue fluid in and out of blood capillaries
  • Carbon monoxide+High blood pressure can damage inner lining of arteries. However, white blood cells can repair the damage and encourage growth 

Atherosclerosis

  • Deposistion of fatty substances like cholesterol under the endotheial lining
  • The deposits can build up enough to break through the inner lining eventually forming plaque in the lumen of the artery. This will reduce size of lumen and restrict blood flow
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Muscular Tissue

They are made from cells that are lengthened due to fibres. Thye contain protien fillaments called actin and myosin that enables muscles to contract and cause movement

Skelatal- Found attached to bones. can control contraction+relaxtion, sometimes contract inrsponse to reflexes

Cardic- Found only in the heart. Contract at a steady rate to mke a heartbeat. No voluntary control

Smooth- found in walls of hollow organs eg, stomach+bladder. No voluntary control

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Skeletal muscle fibre

Need to be able to contract in order to move bones. In muscle cells cells join to make fibres

  • Myofibril- Made from protiens called myofilaments, which enable contraction to take place. The protiens appear as different colour bands; A-band (Dark and I-band (light)
  • Sacromere- When the muscle contracts the sacromere reduces in length.
  • The 2 protiens Actin (thin) and Mysonin (Thick), Actin overlap mysonin.

Slow Twich muscle fibres- more affective as use oxygen to generate energy in the form of ATP for continuous muscle contractions for a long time. Contain more mitochondria and less scarsoplasmic reticlum

Fast twich muscle fibres

  • oxidative- similar to slow twich but contain hydrolyse ATP much more qwickly. Resistance to fatigue
  • Glycolytic- less myoglobin, few mitochondria and capilaries. Large cencentration of glycogen that provides fuel for anarobic respiration  
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