Cells & Microscopy - MICROSCOPY Flashcards by Tatenda Dzingirai

Name 3 main types of microscopes

Light microscope
Electron microscope
Confocal laser scanning microscope ( CLSM )

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Name 2 types of electron microscope

Transmission electron microscope ( TEM )

2. Scanning electron microscope ( SEM )

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Definition of light microscope

Uses visible light to illuminate a thin section of a specimen

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Definition of electron microscope

Uses a beam of electrons to visualise a specimen

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Definition of of CLSM ( confocal laser scanning microscope )

Uses lasers to produce an optical section which is used to produce a 3D image

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What is the max. magnification of a light microscope

2000x

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What is a light microscope used for looking at ( 2 things )

Cells and tissues

- Some living things eg. a single cell layer

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What is the max. magnification of a TEM ( transmission electron)

5 000 000x

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What is a TEM used for looking at ( 4 things )

very thin cross section of an object ( such as a cell )
internal structure of objects
objects at very high resolution
relationships between structures at high resolution

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What is the max. magnification of a SEM ( scanning electron )

500 000x

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What is a SEM used for looking at ( 2 things )

surface of objects at high resolution

- objects in 3D

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Definition of magnification

Number of times larger an object appears compared to the real specimen

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Definition of resolution

Ability to distinguish 2 distinct objects separately and to see detail

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What does resolution depend on

Wavelength of radiation used

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What is the wavelength of visible light

400-700 nm

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What is the max. magnification of a CLSM ( confocal laser scanning )

2000x

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What is a CLSM used for looking at ( 4 things )

thin slices in a sample while keeping sample intact
specific parts of a cell ( eg. Individual proteins) by labelling them with fluorescence
living cells
( highlighted individual components of a cell )

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What does cell theory state ( 3 things )

All living things consist of 1 or more cells
cells are the basic structural and physiological units of all living organisms
cells come from pre-existing cells

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Place the following in order of largest to smallest:

Plant cell 
Chloroplast
Animal cell
Mitochondria 
Nucleus 
DNA
RNA
Cell surface membrane 
Ribosome 
Virus 
Bactria

Plant cell
Animal cell
Nucleus
Chloroplast
Mitochondria / Bacteria
Virus
Ribosome
Cell surface membrane
DNA
RNA

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Name 3 main types of blood cells

Erythrocytes ( red blood cell )
Thrombocytes ( platelets )
Leukocytes ( white blood cell)

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Name 3 main types of Leucocytes ( white blood cells )

Neutrophil
Lymphocytes
Monocyte ( = macrophages once moved into tissues )

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Definition of erythrocytes

Red blood cells

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Description of erythrocytes ( 4 things )

biconcave discs = flexibility squeeze through capillaries
large SA : volume ratio
no nucleus
naturally red in colour

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Function of erythrocytes ( 2 things )

carries oxygen TO respiring tissues around the body

- carries carbon dioxide FROM respiring tissues around the body

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Definition of thrombocytes

- platelets = cell fragments used in blood clotting

Description of thrombocytes ( 3 things )

- Biconvex discs of cytoplasm fragments from giant cells ( megakaryocytes ) - no nucleus - takes a pale stain

Function of thrombocytes

Contributes to blood clotting and clot formation

Definition of leukocytes

White blood cells

Definition of neutrophil

Type of granulated phagocytic white blood cell

Description of neutrophil ( 4 things )

- most numerous leukocyte - lobed nucleus = flexibility - granular cytoplasm - nucleus takes a darker stain than the cytoplasm

Function of neutrophil

Engulfs bacteria by process phagocytosis

Definition of monocyte

Large phagocytic white blood cell, which can develop into a macrophage

Description of monocyte ( 4 things )

- largest kind of leukocyte - large bean shaped nucleus - clear ( agranular ) cytoplasm - nucleus takes a dark stain

Function of monocyte

Carry out phagocytosis in bloodstream and eventually move into the tissues ( now called macrophages )

Definition of lymphocyte

Smallest kind of leukocyte | Cells of the immune system= B or T cells

Description of lymphocytes: B & T ( 3 things )

- large - darkly stained nucleus - clear cytoplasm

Definition of B lymphocyte

Specialised white blood cell which that is produced and matured in the bone marrow

Function of B lymphocyte

Forms plasma cells which produce antibodies

Definition of T lymphocyte

Specialised white blood cell that is produced in the bone marrow and natures in the thymus gland

Name 2 types of T lymphocytes

1. Helper T cells | 2. Cytotoxic T cells

Function of helper T cells

Coordinate immune response

Function of cytotoxic T cells

Destroy infected cells

Definition of differential stain

Staining processes that use more than 1 chemical stain to distinguish between different cellular components

Explain differential stains in more detail

Differential stains are chemicals that bind to some parts of the specimen and make different structures different colours in order to make them visible and increase contrast

Name 3 stains that can be added to live cells

1. Iodine 2. Methylene blue 3. Eosin

Name a stain that can only bind to cells that have been fixed in alcohol ( dead cells )

Leishman’s stain

Why is the process of differential staining used ( 2 things )

- most biological specimens have no colour and are almost transparent - colourless = difficult to differentiate between structures

function of methylene blue stain

Binds to nucleic acids = stains nuclei and ribosomes blue- purple

Function of eosin stain

Binds to cytoplasmic proteins = stains them pink-red

Function of Leishman’s stain

Stains leukocytes = reveal differences in the shape of their nuclei = can be identified in a blood smear

How to prepare a blood smear ( 9 steps )

1. Wear latex free gloves ( prevent contamination of blood ) 2. Place small drop of blood at end of a sterile, clean, dry microscope slide 3. Spreader held at 30° angle = pushed along slide to spread the blood by capillary action = form a smear 4. Label microscope slide with patient details 5. Allow slide to air dry 6. Fix using methanol ( alcohol= dead cells ) 7. Flood with Leishman’s stain & leave for 2 mins 8. Dilute with distilled water & leave for 5-7 mins 9. Wash slide until it appears pale pink

Formula for calculating magnification

I AM Magnification = Image size / Actual size

Formula for calculating actual size

I AM Actual size = Image size / Magnification

I AM triangle what do letters stand for

I = image size A= actual size M = magnification

Millimetres to micrometers

x1000

millimetres to nanometres

x ???

micrometer to millimetre

/ 1000

Micrometre to nanometre

x ???

nanometre to micrometre

x ???

nanometre to millimetre

x ???

Cells & Microscopy - MICROSCOPY Flashcards

(60 cards)