Key Concepts in Biology Flashcards
What is an electron microscope?
A microscope that can magnify at much higher resolution than a light microscope
How can total magnification be calculated?
Total magnification = eyepiece lens x objective lens
What is the magnification triangle?
image height = magnification x object height
What is meant by an instruments resolution?
An instruments resolution is the instruments ability to distinguish between different light
What features do animal cells have?
Nucleus Cell membrane Cytoplasm Ribosomes Mitochondria
What features do plant cells have?
Nucleus Cell membrane Cytoplasm Ribosomes Mitochondria Cell wall Large Vacuole Chloroplasts
What features do plant cells have that animal cells don’t?
Cell wall
Large Vacuole
Chloroplasts
How are sperm cells adapted to their function?
They have a haploid nucleus, a mid piece containing many mitochondria, a long flagellum (tail)
How are egg cells adapted to their function?
They have cytoplasm containing many mitochondria, a haploid nucleus and are large
How are ciliated epithelial cells adapted to their function?
Long and thin with tiny hairs on one end
They also have a lot of mitochondria
Name the common features of a bacteria
No nucleus
flagellum
cell wall
cell membrane
Why are bacteria classed as prokaryotic?
Because they do not have a nucleus
What is the difference between eukaryotic and prokaryotic cells?
Prokaryotic cells don’t have a nucleus, whereas eukaryotic cells do
Where are enzymes normally found?
Stomach, intestines, saliva etc
What is an enzyme?
An enzyme is a protein. They are also biological catalysts
Why are enzymes useful?
Because they speed up reactions, which is useful for life processes
How can you test for starch in foods and what do positive and negative results look like?
Add iodine
Positive: Blue/Black
Negative: Brown
How can you test for reducing sugars in foods and what do positive and negative results look like?
Add Benedict’s reagent and heat in a water bath.
Blue = little sugar
Red = lots of sugar
How can you test for lipids in foods and what do positive and negative results look like?
Shake substance in ethanol, then add water.
Milky colour = lipids
Clear = no lipids
How can you test for proteins in foods and what do positive and negative results look like?
Add potassium hydroxide (alkaline). Add copper(II) sulfate
Blue = negative
Purple = positive
Define Diffusion.
The net movement of particles from an area of high concentration to an area of low concentration.
Define Osmosis.
The net movement of water particles across a partially permeable membrane from an area of higher water concentration to an area of lower water concentration.
Define Active transport.
The movement of particles across a membrane against the concentration gradient.
Which is the only one that requires energy?
Active transport.
