Cells & Microscopy Flashcards
Total Magnification = ?
otal Magnification= Eyepiece magnification x Objective lens Magnification
Magnification = ?
Magnification = image size /actual size (AIM triangle I at the top)
How many millimeters(mm) in a micrometer(um)
1000
How many micrometer(um) in a nanometre (nm)
1000
How to use a light microscope?
- carefully clip the glass slide onto the stage
- select lowest powered obejtive lens
- use coarse focus knob to move stage just below the objective lens
- look down the eyepice. Use coarde focus knob to adjust image into rough focus
- Adjust with fine focus know for a clear image
- if need to see slide with great magnification, lower stage and swap for higher powered objective lens, then refocuse
What do Electron Microscopes use instead of light waves?
Beams of electrons
How are electron microscopes used?
Placed in a vacuum, meaning no air particles will collide with the electron particles
Magnification definition
How many time bigger the image of the specimen observes is in comparison to the actual, real life size of the specimen.
Resolution definition
The ability to distinguish between two separate points. If two separate points can’t be resolved they will be observed as one point and the image will be unclear.
Prokaryotic cells have no …
Nucleus
Prokaryotic cells are …
Simple, smaller, single cells
Where are prokaryotic cells found?
Bacteria
What are the 2 main types of cell
Prokaryotic and eukaryotic
Prokaryotic cells lack what?
Lack organelles
Eukaryotic evolved from ….
Prokaryotic cells
Eukaryotic cells are what compared to prokaryotic cells …
Bigger more complexed
eukaryotic cells are found in …
Animals, plants, fungi, protists
Eukaryotic cells contain…
Organelles, multiple linear chromosomes, single or multicellular
What do prokaryotic and eukaryotic cells both have?
Cytoplasm, DNA, plasma membrane, ribosomes
What are the two types of electron microscopes?
TEMs and SEMs
What does TEM stand for
Transmission Electron Miscroscope
What does SEM stand for
Scanning Electron Miscroscope
What are TEMs used for?
Used to examine thin slices or sections of cells or tissue. 2D
What are SEMs used for?
Has a large geothermal of field so it can be used to examine the surface structure of specimens. 3D
TEMs max magnification is ..
x1,000,000
name 5 organelles
What organelles do animals cells contain?
Cell surface membrane, mitochondrion, ribosomes, nucleus, cytoplasm
Function of a cell surface membrane
To allow substances to move in and out of the cell
Function of a mitochondria
Where aerobic respiration occurs (ATP). Also where energy is released.
Function of ribosomes
Where protein synthesis occurs, making all proteins for the cell.
Function of cytoplasm
The gelatinous liquid that fills inside of a cell and where chemical reactions takes place
Function of a nucleus
Controls all activities of the cell and where all genetic information is stored
name 8 organelles
What organelles do plant cells contain?
Cellulose cell wall, cell surface membrane, cytoplasm, chloroplast, mitochondrion, large permanent vacuole, nucleus, ribosomes
Functions of a large permanent vacuole
Contains cell shape to keep the cell rigid
Function of cell wall
Plant and bacterial cells help the cells stay rigid and maintains integrity, shape and supports and protect the cell. Only plant cells are made of cellulose.
Function of chloroplast
Plant cell organelles that convert light energy into chemical energy via photosynthesis. Also contain chlorophyll.
Function of chlorophyll
A pigment that gives plants their green colour. Absorbs light so the plant can make food via photosynthesis
What are plasmids?
Small rings of DNA that are present in the cytoplasm. Unlike chromosomal DNA, plasmid DNA can move from one bacteria to another, giving variations
name 9 organelles
What organelles do bacterial cells contain?
Capsule, plasma membrane, cell wall, pilli, cytoplasm, plasmid, ribosomes, nucleoid (DNA), flagellum
Function of plasma membrane
Regulates the transport of material entering and exiting the cell
Function of pilli
Short, hair-like structures on the cell surface of prokaryotic cells.
Role in movement, but are more often involved in adherence to surfaces, which facilitates infection, and is a key virulence characteristic.
Function of capsule
Protects cell from ingestion and destruction by white blood cells
Function of flagellum
Flagella are organelles that have long and filamentous appendages. They can rotate or move in a whip like motion to move the bacterium.
Examples of specialised cells?
Nerve cells, muscle cells, sperm cells
What is Chromosomal DNA
The DNA of bacterial cells is found loose in the cytoplasm. Chromosomal DNA is not contained within the nucleus.
Function of nucleoid
Regulates the growth, reproduction, and function of the prokaryotic cell.
Function of Motor Neurone (type of nerve cell)?
- Transmits electrical signals
- Receiving sensory input from the external world
- send and receive signals from your brain
How is Motor Neurone (type of nerve cell) specialised ?
- Elongated structure : allows them to coordinate information from the brain and the spinal cord with the rest of the body
- Long fibre(Axon) : carried messages up and down the body over long distances- speeds up nerve impulses
Function of Muscle cell
Contraction for movement
How are muscle cells specialised for its function?
- Extension of cytoplasm
- an axon
- contains layers of fibre
- high density of mitchondria to provide suffice to energy (via respiration for muscle contraction)
Function of red blood cell (erythrocyte)
Transport oxygen for aerobic respiration.
How are red blood cells specialised for its function?
- contains haemoglobin: red protein that combines oxygen
- no nucleus: so they can contain more haemoglobin
- biconcave shape: to maximize surface area for oxygen absorption
Function of sperm cell (spermatocyte)
Pass the male genetics on during sexual intercourse, reproduction
How are sperm cells specialised for its function?
- flagellum allows them to move by propelling it forward
- head contain nucleus which contains half of the chromosome
- lots of mitochondria - provides energy required
- streamlined so can swim faster
- digestive enzymes at tip of head - breakthrough a hole into wall of the egg
Function of root hair cell
Absorbs water and mineral ions from soil
How are root hair cells specialised for its function?
- large surface areato increase rate of absorption
- roots hairs: increase surface area
- thinner walls than other plant cells so the water can move through easier ( due to shorter diffusion distance)
- no chloroplast: no light underground
- mitochondria: for active transport of mineral ions
- permanent vacuole: contains salt solution which is more concentrated than soil water, maintaining a water potential gradient for osmosis
Function of phloem cells
Transport of dissolved sugars and amino acids
How are phloem cells specialised for its function?
- made of living cells (as opposed to xylem what are made up of dead cells) which are supported by companion cells
- cells joined end-to-end and contain holes in the end cell walls (sieve plates) forming tubes which allow sugars and amino acids (cell sap) to flow easily through (by translocation)
- very few subcellular structures to aid the flow of materials
Function of xylem cells
Transport tissue for water and dissolved ions
How are xylem cells specialised for its function?
- No top or bottom walls between cells to form continuous hollow tubes through which water is drawn upwards to leaves by transpiration
- essentially dead cells, without organelles in cytoplasm to allow free passage of water and dissolved ions
- outer walled thickened with lignin: helps support the plant
Why are Petri dishes and culture media sterilisier before use
to kill the bacteria already on them
Why are inoculating loops used to transfer microorganism to media, passed through the flame
This ensures that no microorganisms enter the mouth of the vessel to contaminate the culture or the medium.
Why Petri dish lids secured with adhesive tape ?
Fix the lid of the Petri dish with adhesive tape to prevent microorganisms from the air contaminating the culture – or microbes from the culture escaping
why are petri dishes stored upside down?
- It lessens contamination from airborne particles landing on them
- prevent the acclamation of water condensation that could disturb or comprise a culture.
Why are school labs cultures incubated at a maximum temperature of 25 degrees
it reduced the likelihood of growth of pathogens that might be harmful to humans
Inhibition = ?
πr^2 (mm^2)
Where are antiseptics used and what is their effect on living cells and microorganisms
- applied to living skin or tissue to prevent infection
- cause little/ no harm to living cells and tissues but kill micro-organisms that could cause disease or infections
Where are disinfectants applied and what effect do they have on cells and microorganisms
Disinfectant
- applied to surfaces, equipment, or other non-living objects
- causes harm to living cells and tissues as well as killing microorganisms present
through which process does bacteria multiply by
- Binary fission
how often do bacteria multiply and in what conditions
once every 20 minutes if they have enough nutrients and a suitable temperature
which 2 mediums can bacteria be grown in
- nutrient broth solution
- as colonies on a agar gel plate
what is required for the investigating the action of disinfectants and antibiotics
uncontaminated cultures of microorganisms
