B1 Key Concepts In Biology Flashcards
How do you use a
light microscope?
- Turn on the light.
- Put the specimen on the stage.
- Move the stage all the way up.
- Look through the eyepiece.
- Focus the image using the focusing knobs.
What is
magnification?
how large the image is compared to the object
What equation links
image size, actual size and magnification?
(I, A, M)
image size = actual size x magnification
I = A x M
I am
Define
resolution.
the smallest distance between two points that can still be seen as two points
(low resolution - blurry image)
What is the function of the
nucleus?
contains all the DNA
What is the function of the
mitochondria?
releases energy
What is the function of the
ribosomes?
makes proteins
What is the function of the
chloroplasts?
to photosynthesise
What is the function of the
cell membrane
control what goes in and out of the cell
What is the function of the
cell wall?
strengthen the cell
What is the function of the
vacuole?
provide the cell with support
What is the function of the
cytoplasm?
(not actually and organelle)
provide area for most chemical reactions to occur
What is the function of the
lysosomes?
break down cell parts and destroy invading viruses and bacteria
Define
organelle.
structure inside a cell
What organelles are present in a
plant cell?
- cell wall
- cell membrane
- chloroplasts
- nucleus
- mitchocondria
- vacuole
- ribosomes
What plant cell organelles can be seen under
both an electron and light microscope?
- cell membrane
- cell wall
- vacuole
- chloroplast
electron microscope allows you to see the
- mitchocondria
- ribosomes
What organelles are present in an
animal cell?
- cell membrane
- nucleus
- ribosomes
- mitchocondria
What plant cell organelles can be seen under
both an electron and light microscope?
- nucleus
- cell membrane
electron microscope allows you to see
- ribosomes
- mitchocondria
What organelles are present in
bacterial cells?
- flagellum
- slime coat
- cell wall
- cell membrane
- chromosonal DNA
- plasmid DNA
What is the function of the
flagellum?
assists movement
What is the function of the
slime coat?
protects from dehydration
What is the function of the
chromosonal DNA?
stores DNA
What is the
plasmid DNA?
a ring of DNA
What are the defining characteristics of
prokaryotic cells?
(and some examples)
- no nucleus
- no mitchocondria or chloroplasts
(e.g. bacteria, archaea)
What are the defining characteristics of
eukaryotic cells?
(and some examples)
- cells with a nucleus
(e.g. animal, plant, fungi, protist)
What does biological mean?
made up of protein
What is a
catalyst?
anything that speeds up reactions
What is
catalase?
the enzyme which catalyses the breakdown of hydrogen peroxide to water and oxygen
Define
active site.
the site on the enzyme where the reaction occurs
Define
substrate.
the molecule the enzyme acts on
Define
product molecule.
the molecule the enzyme produces
Describe the relationship between
temperature and enzyme activity.
Initially, as the temperature increases, enzyme activity increases. Once the enzyme has passed its optimum temperature, enzyme activity slows down.
Explain the relationship between
temperature and enzyme activity.
Initially, as the temperature increases, the enzymes have more energy so move around more. This means that they are more likely to come into contact with the enzyme. Once the enzyme has surpassed its optimum temperature, it starts to denature. Once denatured this cannot be reversed.
Describe the relationship between
pH and enzyme activity.
Enzyme activity works best at its optimum pH. Anything around this is fine. However, anything too much lower or higher denatures the enzyme. This denaturing is reversible.
Explain the relationship between
pH and enzyme activity.
When the pH isn’t optimum for the enzyme, it denatures due to all of the protons that are being added/removed. This denaturing is reversible because the protons can just be added/removed again to reach the optimum.
Describe the relationship between
substrate concentration and enzyme activity.
The higher substrate concentration, the higher enzyme activity. Enzyme activity plateaus at a certain point.
Explain the relationship between
substrate concentration and enzyme activity.
The higher the substrate concentration, the more likely the substrate will react with the enzyme.
Define
osmosis.
the flow of water across a partially permeable membrane from a region of high water potential to a region of low water potential
How can you calculate the energy released from food in calorimetry?
energy released from food
=.
mass of water x temperature rise
/
mass of food sample
Why do food vary in their energy content?
because different foods are made up of different biological molecules
How can you test for
proteins?
carry out the biuret test
purple is a positive result
light blue is a negative result
How can you test for
fats and oils?
(lipids)
carry out the ethanol emulsion test
cloudy is a positive result
clear is a negative result
How can you test for
reducing sugars?
use benedicts solution
red is a positive result
blue is a negative result
How can you test for
starch?
use iodine solution
blue-black is a positive result
no colour change is a negative result
