B1 Flashcards
what is cell theory?
-Cell theory states both plant and animal tissue are composed of cells and cell are the basic unit of life.It also states that cells can develop from existing cells
Light Microscopes
when were they developed?
what are they?
what is the limitations?
what sub-cellular structures do they let us see?
-16th century
-They use visible light and magnifying lenses to observe small objects
-Limitations they have low resolution due to the wavelength of light
-low magnification
-Advantages:portable and easy to use
-The sub cellular structures they let us see is nucleus mitochondria chloroplasts
Electron microscope
what century?
what is it?
what are the advantages?
what is the limitations?
-20th century
-They use a beam of electrons in a vacuum with a wavlength of less than 1nm
-high magnification
-high resolution
-image more detailed using a computer
-limitiations: expensive,training samples must be dead
how do we calculate magnification?
magnification (M)
size of image (i)//actual size (a)
-size of image refers to the length of image always in milimetres
what is prokaryotic?
what is eukaryotic?
-Prokaryotic is a single celled organisms they don’t have a nuclues or membrane bound organelles
-Eukaryotic multicellular organisms such as plants and animals they are complex and they have a nuclues and membrane bound organelles
Animal structure
what is plasma membrane?
what is cytoplasm?
what is nucleus?
what is nucleolus?
what is rough/smooth?
what is golgi apparatus?
-Plasma membrane is composed of a phospholipid layer with proteins embedded in the layer.Membrane is selectively permeable and regulates the tranport of materials in and out of the cell
-Cytoplasm maintains cell shape and stores chemicals needed by the cell for chemical reaction
-Nucleus is surrounded by nuclear envelope,envelope has pores which allows the movement of molecules through it it contains chromatin.Nucleus controls activity and houses the genetic material.
-Rough endoplasmic reticulumn network of membrane bound flattened sacs called cisternae studded with ribosomes.Protein synthesis takes place on the ribosomes and the newly synthesised proteins are transported to the golgi apparatus
-Nucleolus dense spherical sturcture in the middle of the nucleus.Nucleulus makes rna and ribosomes
-Smooth endoplasmic reticulumn network of membrane bound flattened sacs called cisternae NO RIBOSOMES.Is responsible for synthesis and transport of lipids and carbohydrates
-Golgi apparatus a stack of membrane bound flattened sacs.Newly made proteins are modified and packaged into vesicles
Animal structure
what is vesicle?
what is lysosomes?
what is ribosomes?
what is mitochondria?
what is centrioles?
-Vesicles small spherical membrane bound sacs with fluid inside.Transports materials around the cell or out of the cell
-Lysosomes small spherical membrane bound sacs containing hydrolytic enzymes they break down waste material
-Ribosomes protein synthesis occurs at the ribosomes
-Mitochondria they have 2 membranes inner membrane is highly folded to form cristae this is the site of aerobic respiration
-Centrioles they are small tubes of proteins they form spindle fibres during cell division
Plant cell structures
what is cell wall?
what is chloroplasts?
what is vacoule?
what is tonoplast?
what is amyloplast?
what is the plasmodesmata?
what is pits?
-Cell wall made of cellulose -strengthens the cell portects the cell
-Chloroplasts double membrane filled with stroma.Inner membrane contains thylakoids (flattened sacs) a stack of thllakoids is called a granum grana contain chlorophyll pigments.Site of photosnythesis light energy is trapped by chlorophyll and used to produce carbphydrate molecules from h20+c0
-Vacoule contains fluid called cell sap (weak solution for sugars n salts) maintains turgor
-Tonoplast partially permeable membrane of the vacoule allows small molecules through
-Amyloplast double mmebrane contains starch granules responsoble for synthesis and storage of starch granules
-Plasmodesmata enable transport and communication between individual plant cells
-Pits pores in the cell walls of xylem allow water to enter and leave xylem vessels
Prokaryotic cell
what is capsule?
what is ribosomes?
what is nucleolid?
what is plasmid?
what is ribosomes size determined by which sought of S IS IT
WHAT SORT OF S IS EUKARYOTIC AND WHY?
-Capsule slippery layer outside the cell wall protects cell and prevents dessication
-Ribosomes where protein synthesis occurs
-Nucleoid irregularly shaped holds the nuclear material without nuclear membrane the region where genetic information can be found and controls cellular activity
-Plasmid small loops of dna carry genes that may benefit survival of the organism
-Ribosomes size is determined by their ability to form sediment in a solution
-Eukaryotic ribosomes is 80S whereas prokaryotic is smaller and is 70S
why is it importamt to know which is gram positive and gram negative?
Gram positive structure
-It is important to correctly identify the bacteria that cause infections to enable them to decide the most effective treatment
GRAM POSITIVE STRUCTURE
-contains cell wall which contains a thick layer of peptidoglycan
-They have no outer membrane so penicillin can enter
-Penicillin prevents the cross linking of protein chains in peptidoglycan
-Inhibiting an enzyme so cell wall synthesis is disrupted so it bursts so no growth around the discs
-Penicillin prevents the growth around new cells
GRAM NEGATIVE
-Cell wall contains a thinner layer of peptigoglycan surrounded by an outermembrane
-Antibiotic must cross cell wall to be effective
-reduced ability of penicillin to cross the outer membrane
-reduced distruption of cell wall so cell wall continues to grow around the dissc
what is the gram staining technique?
1) 2 stains are added to the bacterial smear crystal violet and safranin
2)If you see a purple stain it means gram positive is present
3) If you see a pink safranin gram negative.This is because their thin cell walls/lipid membranes allow ethanol to wash of all of the crystal violet stain and then retain pink safranin stain
