cells, organelles and microscopes Flashcards
What are organisms made up of?
one or more cells
Where do cells come from?
- All cells come from pre-existing cells
Prokaryotes
Organisms that consist of cells without a membrane around the nucleus, e.g. bacteria
How are Prokaryotes classified?
- Eubacteria
- Archea
Eubacteria is…?
complex in structure and are found under neutral conditions.
Where can you find Eubacteria?
-you can find them in the human body, in some foods and practically everywhere around us.
Archea are..?s
a single celled prokaryotes
Prokaryotes don’t have?
membrane bound nucleus or organelles
Plasma Membrane
- Thin membrane surrounding the cell
- Keeps cell shape
- only some substances can pass through the membrane.
Cytoplasm
- jelly like Fluid where chemical reactions occur
- gives the cell shape by filling it
Plasmid
- small piece of DNA (not part of the chromosome) found in the cytoplasm
- carry genes giving bacteria resistance to antibiotics
What do prokaryotes have?
- plasma membrane
- cytoplasm
- ribosomes
- plasmid
What do some prokayotes have?
- cell wall
- flagellum
Flagellum
- helps them move (motile – relating to motility; capable of moving or self-propelling)
Capsule outside the cell wall - helps them stick makes them more virulent (The ability of a pathogenic organism to cause disease) – as it is harder for immune system and antibiotics to attack the inner bacterium.
What can prokaryotes be?
- Photosynthetic
- Chemosynthetic
Photosynthesis?
produce food via sunlight
Chemosynthetic
runs on chemical energy to produce food
Eukaryotes are
complex cells consisting of ..?
- Plasma/cell membrane
- cytoplasm
- a membrane-bound nucleus, and organelles (structures that have a specific function)
Eukaryotes are classified into
- Plants
- Animal
- Protist (seaweed, dinoflagellates, diatoms (plankton))
- Fungi (Tinea, thrush, mushrooms, toadstools).
Eukaryotes cells contain
- Plasma Membrane
- Nucleus
- Nucleolus
- Ribosomes
- Endoplasmic Reticulum
- Golgi Apparatus
- Mitochondria
- Chloroplasts
- Lysomes
- Vacuoles
- Centrioles
- Cell wall
- Cytoskeleton
Nucleus
- acts as the control centre of the cell as it coordinates functions
- contains DNA ( genetic information)
- It is enclosed by a nuclear membrane which allows the transfer of substances via pores (tiny holes)
Nucleolus
- Located in Nucleus
- Creates ribosomal RNA (r RNA) which leaves nucleus to make ribosomes for the cell
Ribosomes
- scattered through the cytoplasm or attached to the endoplasmic reticulum where protein synthesis occurs
Endoplasmic Reticulum
- Parallel, flattened cavities, lined with a membrane, involved in the transport of substances
Rough E.R
- Lined with ribosomes
Smooth E.R
- do not have ribosomes attached, and it’s involved with the formation and transport of lipids and steroids.
Golgi apparatus
- This is a stack of flat membranes that is involved in carrying out the processing of proteins generated in endoplasmic reticulum
- It is associated with the endoplasmic reticulum
Mitochondria
- This is a stack of flat membranes that is involved in final processing and proteins of proteins into vesicles occurs.
- It is associated with the endoplasmic reticulum
Chloroplasts
- found in plant cells, some bacteria and protists
- contain the green pigment chlorophyll which absorbs light energy
- The inner membrane is folded for more surface area
Lysomes
- vesicles that contain powerful digestive enzymes that break down debris and foreign material
Vacuoles
- Stores water and food wastes
- Helps get rid of wastes
- Large vacuole’s fluid, or cell sap, serves as a storage space for sugars minerals, proteins and water
Centrioles
- Aid in cell division
Cell Wall
- Made of cellulose to protect and keep the cell’s shape and rigid structure
- It can have plamadesmata which allows communication and transport between cells
Cytoskeleton
- system of fibres within a cell that helps establish its shape and aids in movement and cell division.
Light Microscope
- Specimen are illuminated with light
- are compound microscopes, which means, they use several lenses to obtain high magnification
Scanning electron microscope
- The specimen is coated in gold and the electrons bounce off to give you and exterior view of the specimen.
- The pictures are in black and white. ( 3D View )
- Cells are dead.
Transmission Electron Microscope
- Thin slices of specimen are obtained.
- The electron beams pass through this. ( gives a 2D View)
- It has high magnification and high resolution.
- Cells are dead and process can distort material
How do you get the magnification?
Eyepiece lens number X Objective lens number
