C3 Biological molecules Flashcards
light microscope
-Poor resolution due to the long wavelength of light
-living samples can be examined and a colour image is obtained
Transmission electron microscope
-High magnification and resolution
-Electrons pass through the specimen to create an image
Scanning electron microscopes
-High magnification and resolution
-Electrons bounce of the surface of the specimen to create an image
Laser scanning confocal microscopes
-High resolution and 3D imaging
-Laser light is used to create an image
Types of microscopes (4)
-Light microscopes
-Transmission electron microscopes
-Scanning electron microscopes
-Laser scanning confocal microscopes
What is the definition of resolution?
- minimum distance between two objects in which they can be viewed as separate.
- Optical microscope = determined by the wavelength of light
- Electron microscope = determined by the wavelength of the beam of electrons
What is the definition of magnification ?
Refers to how many times larger the image is compared to the object
What is an eyepiece graticule ?
inside light microscopes , there is a scale on a glass disc called the EPG
what do we use the eyepiece graticule for?
Used to measure the size of objects you are viewing under the microscope
Why do we need to calibrate our eye piece graticule?
We need to calibrate the eyepiece each time we change the objective lens as the magnification changes
How do we calibrate? (3)
1) Line up the stage micrometer and eye piece graticule looking through the eyepiece whilst looking through the eyepiece
Why is water represented in a v shape?
- Each bond represents a pair of shared electrons
- 2 lone pair of electrons on the oxygen
What is more electronegative in water?
O is more electronegative than H
- electrons will orbit around the o a lot more than the H
what is a polar molecule
Unequal share of electrons
Example of polar molecules
glucose
HCL
What bond is formed between different polar molecules ?
hydrogen bond
why do we represent hydrogen bonds as dotted lines?
they are weak bonds, straight lines are covalent bonds
Important functions of water
Using examples of E and P
- they can be a solvent , mainly dissolve polar molecules EG: enzymes
- Medium for chemical reactions
-transport medium
-coolant for your body
-habitat
Prokaryotes use water to obtain some elements and compounds for their survival.
Water’s solvent properties allow it to dissolve and transport many biological molecules, such as carbohydrates, proteins, and nucleic acids
what is cohesion ?
hydrogen bonds between water molecules
What is adhesion
Force between water molecules and the surface it is attached to
What is glucose known as?
a hexose (6carbon) monosaccharide
What are the two different types of glucose molecules?
-alpha
-beta
What bonds do glucose molecules form
glycosidic bonds
How do we form glycosidic bonds between glucose molecules?
condensation - when two glucose molecules join together and produce a water molecule