Basic Components Of Living Systems Flashcards by Daniel Cansancio

What is a light microscope used for?

Observing living and dead specimins

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What are the pros and cons of a light microscope?

Pros: Cheap, Portable, Easy To Use, Can Study Living Specimens

Cons: Limited Magnification, Poor Resolution

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What is a laser scanning confocal microscope used for?

Creating a high Resolution, high contrast image, at different depths of the specimen

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What is transmission electron microscope be used for?

Viewing the surface of objects under high Magnification and Resolution

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What is a scanning electron microscope used for?

Viewing the surface of objects under high Magnification and Resolution

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What are the pros and cons of an electron microscope?

Pros: Very high magnification and excellent resolution

Cons: Specimen need to be dead, very expensive, very large, requires great skill and training to use

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What is the difference between a transmission and an scanning electron microscope?

TEM sends a beam of electrons of electrons through the specimen, the SEM bounces electrons off the surface

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What is the difference between light and electron microscopes?

Light microscopes uses lenses to focus a beam of light, Electron microscopes uses a beam of electrons which are focused by magnets

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What is an eyepiece graticule?

A small ruler fitted to a light microscope’s eyepiece. It must be calibrated using a stage micrometer before being used to measure specimens

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What is a stage micrometer?

A millimetre long ruler etched onto a slide, it has 100 divisions (each of 0.01mm or 10 micrometers). It is used to calibrate the eyepiece graticule

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Why do we stain specimens?

To provide more contrast and to make it easier to distinguish certain parts

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What is Differential Staining?

Using a stain to distinguish between either 2 organisms or between organelles of a specimen due to preferential absorption of stain

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What is the formula to calculate Magnification?

Magnification = Image Size / Actual Size

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What is the formula to calculate the Actual Object Size?

Actual Size = Image Size / Magnification

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How do we work out Image Size

Use a ruler and measure the image

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What is Magnification?

A measure of how much larger the image of a specimen looks under the microscope

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What is Resolution?

The ability to distinguish between two adjacent individual points as seperate

What are the maximum Resolutions of the different microscopes?

Light = 200nm
SEM = 10nm
TEM = 0.2 nm

What is the maximum Magnification of the different microscopes?

Light = x1500
SEM = x100000
TEM = x 500000

What are the main structures of all Eukaryotic Cells?

Nucleus, Nucleolus, Cytoplasm, Cytoskeleton, Plasma Membrane, Mitochondria, Golgi Apparatus, SER, RER, Ribosomes

What is the structure and function of the Nucleus?

Surrounded by a double membrane (nuclear envelope).
Contains Chromatin (DNA wrapped around Histones)
Stores human genomes
Controls cell by providing instructions for protein synthesis

What is the structure and function of the Nucleolus?

Made of RNA

- Produces Ribosomes

What is the structure and function of the Nuclear Envelope?

Double membrane embedded with channel proteins forming pores
Separates Nucleus from the rest of the cells
Pores allow Ribosomes and mRNA to leave the Nucleus

What is the structure and function of the RER?

System of fluid filled membranes studded with Ribosomes
Continuous with the Nuclear Membrane
Large surface area formed by folding, enables lots of protein synthesis
Proteins pinched off in vesicles transported to the Golgi Apparatus

What is the structure and function of the SER?

- System of fluid filled membranes - No Ribosomes - Contains enzymes for Cholesterol, Lipid and Phospholipid synthesis

What is the structure and function of the Golgi Apparatus?

- Stack of flattened filled membrane bound sacs - Vesicles form RER join at the cis face - Modified by adding sugar to make Glycoproteins, adding Lipids to form Glycolipids - Folding proteins into their 3D shape - Modified proteims are pinched off from RER into transport Vesicles

What is the structure and function of the Ribosomes?

- 2 Subunits: large and small - Made of mRNA - Proteins synthesised here

What is the structure and function of the Mitochondria?

- Double membrane bound - Inner membrane folded into cristae within fluid filled matrix - Contain own DNA and 70s Ribosomes - Site of Aerobic Respiration

What is the structure and function of the Lysosomes?

- Membrane bound sacs containing Hydrolytic (digestive) Enzymes, break down old organelles and foreign matter for reuse

What is the structure and function of the Chloroplasts?

- Double membrane bound - Inner membrane forms flat disks filled with Chloroplasts called Thylakoids, in stacks called Granum - Surrounded by a fluid matrix called the Stroma - Contain own DNA and 70s Ribosomes - Site of Photosynthesis

What is the structure and function of the Plasma Membrane?

- Phospholipid layer, Cholesterol, Proteins , Glycoproteins, Glycolipids - Separates cell contents from external environment - Controls what enters and leaves the cell - Identifies cell as self - Acts as a reporter for various chemicals, site of chemical reactions

What is the structure and function of the Centrioles?

- Present in animals only - 2 bundels of Microtubules at eight angles - Used as an anchor point to separate chromosomes during cell division - Forms basis of Cilia

What is the structure and function of the Cell Wall?

- Present in plants and fungi only - Bundles of cellulose fibres in plants - Chitin in fungi - Provide support and strength, maintaining the cell’s shape - Prevents the cell from bursting when turgid - Permeable to allow solutions through

What is the structure and function of the Flagella?

- 9 pairs of microtubules surround 2 lone microtubules - Membrane covers the whole thing - Used for moving unicellular organisms around

What is the structure and function of the Cilila?

- 9 pairs of Microtubules surround 2 lone Microtubules - Membrane covers the whole thing - Present in great numbers - Move together in a wafting pattern to move single celled organisms - When present on tissues waft to move fluids such as Mucus

Which structures are involved in the production of proteins?

Nucleus, RER, Transport Vesicles, Golgi Apparatus

What is the structure and function of the Cytoskeleton?

- Microfilaments made of Actin to allow cell movement and Cytokinesis - Microtubules made of Tubilinsscaffold like structures to give cell shape - Intermediate fires give mechanical strength, maintaining integrity

What do Prokaryotes and Eukaryotes have in common?

Plasma Membrane, Cytoplasm, Ribosomes, DNA, RNA

What is different between Prokaryotic and Eukaryotic Cells?

- Prokaryotes have no: Nucleus, Centrioles, Membrane bound organelles (Mitochondria, RER, SER, Golgi Apparatus) - Prokaryotes also have: Pepidoglycan Cell Wall, Smaller Ribosomes, Naked Loop of DNA, Plasmids

How do Prokaryotes divide?

Binary Fission