B1.1 Flashcards
What are the structures inside cells called?
Subcellular structures
What are the two main types of cells?
Eukaryotic Cells
Prokaryotic Cells
Eukaryotic Cell
Nucleus - controls the activities of the cell and also contains the genetic material
Cell Membrane - barrier which allows substances to pass in and out of the cell
Mitochondria - where respiration happens
Cytoplasm - A jelly like substance. Chemical reactions that keep the cell alive happen here
Difference between the two types of cells
Eukaryotic - contains genetic material in the nucleus. Complex and relatively large. Size is between 10u and 100u.
Prokaryotic - has no nucleus, genetic material floats in the cytoplasm. Simple and smaller. Size is between 1u and 10u.
Plant Cells
Chloroplast - contains green chlorophyll which transfer sun energy to the plant as light
Vacuole - Full of cell sap and it helps the cell keep its shape and supporting the plant to stay upright
Cell Wall - surrounds the cell and is made from a thought fibre called cellulose. Makes the wall rigid and supports the cell
How many cells do bacteria have?
Unicellular organisms - consist of just one cell
What is the size of bacteria?
1um
Bacterial cell extra structures
Flagella - tail like structure which allows the cell to move through liquids
Plasmid - a piece of DNA which is used to store extra genes.
Light microscope
Helps to observer small structures in detail
Equation for total magnification of a microscope
Eye piece lens magnification x Objective lens magnification
Why stains cells before viewing with a microscope?
Many cells are colourless so it makes them easier to observe.
Methylene blue - makes it easier to see the nucleus of an animal cell
Iodine - makes it easier to see plant cell nuclei
Crystal violet - stains bacterial cell walls
What is a electron microscope?
They use electrons instead of light to produce an image. The greater resolution is achieved by using high-energy electrons as the light source.
Types of electron microscopy
Transmission electron microscopes produce the most magnifies image
Scanning electron microscopes produce a three dimensional image of a surface
Light microscopes advantages
Cheap to buy and operate Small and portable Simple to prepare sample Natural colour of sample is seen Specimens can be living or dead Resolution up to 0.2um
Electron microscopes advantages
Expensive to buy and operate Large and difficult to move Sample preparation is complex Black and white produced Specimens are dead Resolution up to 0.1nm
