Cell structure Flashcards
What are the two types of cell?
Prokaryotic(bacteria, fungi) and eukaryotic (animals, plants)
What is the function of the nucleus and what structures does it have?
The nucleus contains
-Nucleolus(Synthesising of ribosomes)
-Nuclear Pores(Where mRNA strands leave the nucleus for protein synthesis)
-Nuclear envelope(Double membrane
-Genetic information in the form of chromosomes
The function is to manage genetic material
What is the function of the cytoplasm?
Jelly like substance in which all the intercellular organelles are based, also the site of chemical reactions.
What is the function of the Phospholipid bilayer?
-Acts as a semi permeable membrane in which allows certain substances needed for cellular metabolic reactions.
How does the cytoskeleton form, what is its function, and where is it based?
The cytoskeleton can be found in the cytoplasm of the cell.
It is made of:
-Microfilaments(made of actin, moves cell & contracts in cytokinesis)
-Microtubules(Made of globular tubulin that form tubes, determines -
cell shape and acts as tracks for movement of organelles)
-intermediate fibres(Gives the cell strength)
Functions:
-Holds organelles in place
-allows cell to change shape (exo&endocytosis)
-Makes up centrioles
What are centrioles?
Made of microtubules which assemble and order spindle fibres in cell division
What are flagellum?
Tail like projects which detect changes in the cells environment and helps it move
9+2 arrangement of microtubules
What are Cilla?
Hair like extension, move particles that surround the cell by beating rhythmically
What are ribosomes
Made of Ribosomal RNA and Proteins and they have a function of synthesising proteins
What is the rough ER
Made of folded membrane which projects of the nucleus, it contains ribosomes which synthesises the mRNA released at the nucleolus
The actual ER takes the produced proteins and glycoproteins and packages them into vesicles
What is the smooth ER
Secretes lipids and carbohydrates which is then packaged into vesicles
What is the Golgi apparatus
Vesicles from smooth and rough ERs fuses with it and they are modified before being put into vesicles and sent off.
if the vesicle is filled with enzymes its called a lysosome(Digestive enzymes lysozymes break down worn down biological molecules and cell membrane of bacteria)
What is the Mitochondria, structure and function?
The mitochondria is a double membraned organelle in which contains the cristae( this is a fluid in which has enzymes that speed up the reaction for aerobic respiration(produce ATP))
Also contain ribosomes and DNA(replication)
What is the cell wall?
Made of cellulose in plants and peptoglyican in bacteria which supports the cell and keeps it turgid
What is the Vacuole
Filled with cell sap it helps keep the turgidity of the cell,helps maintain water and storage of molecules like salts and minerals
What is the cholorplast?
Double membraned organelle which contains thylakoid structures which stack to make grana(Filled with cholorphyll) for photosynthesis, the thylakoids and joined by a thin sheet oif lamella. The grana sit in structures called stroma which is the light idenpendent stage of the photosynthesis cycle. Also contains ribosomes starch grains and some DNA for replication.
What are prokaryotic cells
Sinlge-Celled Organsims that lack membrane bound organelles
What do prokaryotic cells contain
Always present:
-cytoplasm
-cell surface membrane
-70s ribosomes
-pepditdoglycan cell wall
-circular DNA
What is sometimes present in prokaryotic cells
Capsules: Stops excessive water loss, host immune system
Flagella: Move away from danger and toward food
Plasmids: small loops of DNA
What are viruses
Non-living, acellular, parasitic particles
Acellular:Not made up of cells or divided into cells
Parasitic: One spec
What are the types of microscope
Light/Optical, Electron microscope, Laser scanning confocal microscope
Explain the light microscope
Light is passed onto the specimen and the magnifers are used to enlarge the image
Low magnificaiton (1500x)
resolution only half the wavelength of light so 200nm
What are the different objective lenses of light microscopes
x4, 10, x40, x100
What is a Laser scanning/confocal microscope
Uses lasers to scan an object, fluorecent dyes are used to build the image
High resolution, high contrast
Multiple images combine to make a 3D image
What are Tems
Transmission electron microscopes use an electromagnet to transmit electrons through a species and denser parts absorb more electrons(darker in image)
Advantages:
High resolution
interal structures can be seen
Disadvantages:
-Long process
-cells must be dead
-No colour
0.1nm resolution 500,000x magnification
What are SEMs
Scanning electron microscopes fire a beam of electrons at the specimen, the electrons bounce of the object and are hit by a dector which then builds an image(can be 3d)
Disadvantages:
Lower resolution that Tems
Cant produce colour
cells can be alive
100,000x resolution
0.1nm resolution
What is the equation for magnification
Magnification = image size/ actual size
What are the main features of a light microscope
Cheap and easy to operate, small and portable, sample preperation is simple, sample prep doesnt lead to distortion, vaccum not required, natural colour seen. x2000 magnification, resolution of 200nm specimen can be alive
What are the features of an electron microscope
expensive and hard to operate, Large and needs to be installed, complex sample prep, vaccum required, black and white images, X500,000 magnification 0.5 nm resolving power specimen has to be dead
what is metabolism
Synthesis and breaking down of molecules
