BTEC Unit 2 Applied Science Questions And Answers
/2025
Suggest why laboratory technicians must complete health and safety training
before they are allowed to work in the laboratory
to ensure that they are aware of the risk and hazards in laboratories and how to deal
with them.
Information that must be recorded for samples taken
date
name of person handling samples
location (where sample is from and where it is transported to)
Flame test colours
Barium (Ba2+)= Pale Green
Copper= Green Blue
Lithium= Crimson Red
,Sodium (Na+)= Yellow
Potassium (K+)= Lilac
Calcium (Ca2+)= Orange-red
Properties of a suitable internal standard
Internal standard is chemically related to the compounds that are being analysed
but it should not be naturally present in the sample.
Compounds which have the same functional groups.
Why are tubes containing blood samples enclosed in plastic watertight containers
Prevents degradation by water.
Two containers limits possibility of loss sample if one container is broken.
2 ways of reducing risks associated with hazards in labs
Carry out risk assessment
Use PPE for protection
,Train staff in necessary procedures
Comparing light and electron microscopes
Light Microscope
•Rely on light rays
•Typically magnify objects by 1000 to 2000 X
•Images seen in 2D
•Live specimen can be seen
Electron Microscope
•Electrons bombarded using high levels of energy
•Specimen is killed
•Colours cannot be detected
•Magnification roughly 2,000,000 X
How can the width of human hair be calculated using a graticule and a Light
Microscope
•Mount hair on Microscope slide,use sellotape to hold the hair down.
•Measure number of divisions corresponding to width of hair on graticule.
, •Look through graticule at a calibration slide to find number of divisions on
calibration slide corresponding to divisions on graticule.
•Calculate the true distance corresponding to divisions.
•Calculate width of hair.
Explain how Gel Electrophoresis can be carried out in a school or college
laboratory
•Prepare the agarose gel tray, place this tray into Electrophoresis chamber.
•Submerge gel using diluted electrophoresis buffer.
•Load wells with dye samples and place safety cover.
•Connect wires to the power source and begin electrophoresis by loading current
through the gel.
•Use a timer to observe time taken for dyes to travel.
•Once completed remove gel and casting tray from chamber.
DNA samples are loaded into wells at one end of the gel. DNA fragments are
negatively charged so they are attracted to positive electrode. Small fragments
move through gel faster than larger ones. DNA-binding dyes will show same sized
DNA fragments.
Types of Chromatography
High Performace Liquid Chromatography- HPLC
/2025
Suggest why laboratory technicians must complete health and safety training
before they are allowed to work in the laboratory
to ensure that they are aware of the risk and hazards in laboratories and how to deal
with them.
Information that must be recorded for samples taken
date
name of person handling samples
location (where sample is from and where it is transported to)
Flame test colours
Barium (Ba2+)= Pale Green
Copper= Green Blue
Lithium= Crimson Red
,Sodium (Na+)= Yellow
Potassium (K+)= Lilac
Calcium (Ca2+)= Orange-red
Properties of a suitable internal standard
Internal standard is chemically related to the compounds that are being analysed
but it should not be naturally present in the sample.
Compounds which have the same functional groups.
Why are tubes containing blood samples enclosed in plastic watertight containers
Prevents degradation by water.
Two containers limits possibility of loss sample if one container is broken.
2 ways of reducing risks associated with hazards in labs
Carry out risk assessment
Use PPE for protection
,Train staff in necessary procedures
Comparing light and electron microscopes
Light Microscope
•Rely on light rays
•Typically magnify objects by 1000 to 2000 X
•Images seen in 2D
•Live specimen can be seen
Electron Microscope
•Electrons bombarded using high levels of energy
•Specimen is killed
•Colours cannot be detected
•Magnification roughly 2,000,000 X
How can the width of human hair be calculated using a graticule and a Light
Microscope
•Mount hair on Microscope slide,use sellotape to hold the hair down.
•Measure number of divisions corresponding to width of hair on graticule.
, •Look through graticule at a calibration slide to find number of divisions on
calibration slide corresponding to divisions on graticule.
•Calculate the true distance corresponding to divisions.
•Calculate width of hair.
Explain how Gel Electrophoresis can be carried out in a school or college
laboratory
•Prepare the agarose gel tray, place this tray into Electrophoresis chamber.
•Submerge gel using diluted electrophoresis buffer.
•Load wells with dye samples and place safety cover.
•Connect wires to the power source and begin electrophoresis by loading current
through the gel.
•Use a timer to observe time taken for dyes to travel.
•Once completed remove gel and casting tray from chamber.
DNA samples are loaded into wells at one end of the gel. DNA fragments are
negatively charged so they are attracted to positive electrode. Small fragments
move through gel faster than larger ones. DNA-binding dyes will show same sized
DNA fragments.
Types of Chromatography
High Performace Liquid Chromatography- HPLC
