Similarities in prokaryotic and eukaryotic cells
- cell surface membrane
- cytoplasm
- ribosomes
Preparing microscope slide with solid specimen
- Use scissors or a scalpel to cut out a sample of tissue/peel away a thin later of cells
- Place the sample onto the slide (sometimes a drop of water is added before)
- Apply a stain (normally iodine or methylene blue)
- Gently lower a coverslip over the specimen and press down to remove any air bubbles
Magnification definition
the number of times larger an image is than it actually is (M=I/A)
Resolution definition
the ability to distinguish between two objects very close together
Features of a prokaryotic cell
- unicellular
- generally 1–5 µm diameter
- peptidoglycan cell walls
- circular DNA
- 70S ribosomes
- absence of organelles surrounded by double membranes
- no true nucleus (genetic material not enclosed)
Features of a eukaryotic cell
- 10-100um
- linear DNA in chromosomes in the nucleus
- 70S (in mitochondria + chloroplasts) and 80S ribosomes
- Contain organelles surrounded by double membranes
- multicellular
- true nucleus, enclosed by a nuclear envelope
Overall magnification formula
Objective lens x eyepiece lens (always x10)
Virus structure
all viruses are non-cellular structures with a nucleic acid core (either DNA or RNA) and a capsid made of protein, and that some viruses have an outer envelope made of phospholipids
ATP use
cells use ATP from respiration for energy-requiring processes
differences between plant and animal cells
- plant cells contain cellulose cell wall while animal cells don’t have a cell wall
- animal cells contain centrioles
- Plant cells have a large central vacuole while animal cells have either many small ones or none at all
- Plants contain chloroplasts for photosynthesis while animal plants don’t
- Plant cells may contain plasmodesmata
resolution of electron and light microscope
- e is 0.5nm
- light is 200nm
magnification range of electron and light microscope
Light microscopy typically has a magnification range of 40x to 1000x.
Electron microscopy can provide much higher magnifications, ranging from 1000x to 10,000,000x, allowing the observation of subcellular structures and even individual molecules.
Cell surface membrane structure + functions
- Controls the exchange of materialsbetween the internal cell environment and the external environment (known as partially permeable)
- Very thin
- Phospholipid bilayer (hydrophilic head and hydrophobic two tails)
- Diameter of about 10nm
Membrane surrounding vacuole in plant cells
Tonoplast
Nucleolus structure + function
Ribosome synthesis
Centrioles structure + function
Aids in mitosis
- 9 groups of three microtubules
centrosome, which organises the spindle fibres during cell division.
Golgi apparatus structure + function
- modifying and packaging of proteins into vesicles for transport within and out of the cell
Smooth endoplasmic reticulum structure + function
- series of membranes that form flattened sacs and branched tubules
-lipid synthesis and transport - steroid hormone production
- carbohydrate metabolism
- detoxification of drugs
- stores calcium ions
Rough endoplasmic reticulum structure + function
- production (from ribosomes) and processing of proteins
- series of membranes that form flattened sacs and branched tubules has ribosomes attached
Ribosome structure + function
- protein synthesis
- not bound by a membrane
What is the eyepiece graticule?
The eyepiece graticule is an engraved ruler that is visible when looking through the eyepiece of a microscope. Eyepiece graticules are often divided into 100 smaller divisions known as graticule divisions, or eyepiece units
calibration value
1 graticule division = number of µm ÷ number of graticule divisions
nucleus structure + function
- Contains genetic material for the synthesis of proteins
- site of transcription of genes and production of mRNA
nuclear envelope structure + function
- 2 membranes
- contains nuclear pores (regulating passage between cytoplasm and nucleus)
