Structure & Function Flashcards
What is the function of the nucleus?
Contains coded genetic information (DNA) + controls the metabolic activities of the cell
What is the function of the nucleolus?
Produces ribosomes
What is the function of the Golgi apparatus?
Modifies & packages proteins
What is the function of the mitochondria?
Site of cellular respiration, producing ATP
What is the function of the cytoplasm?
Jelly-like fluid where chemical reactions happen
What is the function of the cytoskeleton?
- Shape & stability
- Holds organelles in place
- Controls cell movement
- Controls organelle movement
What is the function of the ribosomes?
Responsible for protein synthesis
What is the function of the SER?
Responsible for synthesis & storage of lipids & carbohydrates
What is the function of the RER?
Responsible for synthesis & transport of proteins
What is the function of the centriole?
A component of cytoskeleton involved in assembly& organisation of spindle fibres during cell division (9+2 arrangement)
What are the 3 differences between plant and animal cells?
Plant cells have:
- Chloroplasts
- Vacuole
- Cell wall
What 7 key organelles do prokaryotic cells have?
- Capsule
- Cytoplasm
- Ribosomes
- Nucleoid
- Plasma membrane
- Flagellum
- Cell wall
What is the function of the cell wall?
Provides strength and rigidity but is permeable to many small molecules
What are prokaryotic cell walls made up of?
Peptidoglycan
What are plant cell walls made up of?
Cellulose
Describe light mircoscopy
Uses UV light and several lenses to magnify the image of a specimen
Describe electron microscopy
Uses electromagnetic lenses to focus a high velocity electron beam under a high vacuum
What are the 2 types of electron microscopy?
- Transmission
- Scanning
Describe bright-field microscopy
Uses a compound microscope to view fixed specimens or live cells
What is the difference between confocal and immunofluorescence microscopy
Fluorescence Microscope:
- Fluorescent antibodies ‘stain’ specific organelles/structures within the cell
Confocal Microscope:
- Creates a sharper image as it looks at a single focal plane
What is the wavelength of light?
400-700nm
What is the wavelength of a TEM and a SEM?
0.005nm
Describe the specimen in a light microscope
Living/non-living on slide
Describe the specimen in a TEM
- Non-living
- Copper grid
- Vacuum
Describe the specimen in a SEM
- Non-living
- Metal disc
- Vacuum
What is the maximum resolution of a light microscope?
200nm
What is the maximum resolution of a TEM?
0.5nm
What is the maximum resolution of a SEM?
3-10nm
What is the maximum magnification of a light microscope?
X 1500
What is the maximum magnification of a TEM?
At least X 500,000
What is the maximum magnification of a SEM?
X 100,000
What is the type of image displayed from a light microscope?
2D colour
What is the type of image displayed from a TEM?
2D black and white
What is the type of image displayed from a SEM?
3D black and white
Colour can be added on a computer
Stains for a light microscope
Coloured dyes
Stains for TEM
Heavy metals
Stains for SEM
Carbon or gold
What is the function of a stage micrometer?
Calibrates the eyepiece graticule so that it can be used to make measurements
What protein forms microtubules?
Tubulin
What protein forms microfilaments?
Actin
Describe the structure of chloroplasts
- Double membrane
- Stromatolites - fluid enclosed
- Thylakoids - flattened sacs
- Granum - several thylakoids stacked together
- Lamellae - join grant together
How are prokaryotes different to eukaryotes? (8 points)
Prokaryotes:
- Unicellular
- Nucleus not present
- DNA circular (loop of DNA)
- Has extra DNA called plasmids
- Organelles are non membrane-bound
- Ribosomes are smaller (70s)
- Reproduce through binary fission
- Cell wall made from murein
Describe the production and secretion of proteins
1- Nucleus contains the gene for the protein (site of transcription, DNA into mRNA)
2- Protein synthesis translation (mRNA into a.a chain) takes place on ribosomes often on RER
3- Protein transported to golgi in vesicle
4- Golgi modified the protein
5- Protein is packaged into a golgi vesicle
6- Vesicle transported to cell-surface membrane
7- Vesicle fuses to membrane and enzyme leaves cell through exocytosis
What does the phospholipid bilayer consist of?
- Hydrophilic phosphate head
- Hydrophobic lipid tails
- Integral membrane proteins