SB1 Flashcards
What is resolution
The distance between two points that can be seen as two points
What is the formula for magnification
Eyepiece lens x Objective lens
or
Size of image ÷ real size of object
How do you get from milli to micro to nano to pico
x by 1000 each time
How do you get from pico to nano to micro to milli
÷ by 1000
Differences and similarities between light and electron microscopes
- Used beam of electrons instead of light
- Electron microscopes provide a higher resolution
- Electron microscopes have a larger magnification
- Both use radiation
- Electron microscopes cannot use living organisms, light microscopes can
- Electron microscopes are expensive
What is a eukaryotic cell
A cell with a nucleus
What does the cell membrane do
Controls what leaves and enters
What does cytoplasm do
Where most of the organelles are and where most of the cell’s activity occur
What does the mitochondria do
It’s where aerobic respiration occurs
What does the nucleus do
Control’s cell activity and contains chromosomes which contain DNA
What do ribosomes do
They make new proteins for a cell
What does the cell wall do
Supports and protects the plant cell
What do chloroplasts do
They contain chlorophyll and traps energy from the sun, they also cause the leaf to be green
What do vacuoles do
Stores cell sap which keeps the cell firm and rigid
What do microvilli do
They’re tiny folds that increase the surface area of the intestine to allow more molecules to be absorbed
What are enzymes
Biological catalysts made of proteins that speed up reactions without being used up
How can cells be equipped with a lot of energy
They have a lot of mitochondria
What is fertilisation
When a sperm and egg cell fuse to create a zygote
List adaptations of an egg cell
- After fertilisation, the cell membrane becomes hard
- Cytoplasm is packed with nutrients to supply zygote with energy
- Haploid nucleus
- Jelly coat for protection, becomes hard after fertilisation
List adaptations of a sperm cell
- Acrosome at the tip contains enzymes to break down substances in the egg cell
- Mitochondria arranged in a spiral around top of the tail to release lots of energy, powers the tail
- Tail to swim
What are cilia used for
To sweep substances along
What adaptations does an oviduct have
Ciliated epithelial cells to sweep substances along
What does prokaryotic mean
A cell without nuclei
What are plasmids
Small loops of DNA that controls cell activity
Name two organelles of bacteria cells that animal cells never have
Cell wall- for support
Flagellum (not all bacteria have)
What are proteins broken down into
Amino acids by digestion
What is starch broken down into
Glucose molecules
What are lipids broken down into
Fatty acids and glycerol
Where are amylase found and what do they do
Found in the saliva and small intestine and catalyse the break down starch into sugars
Where are catalase found and what do they catalyse
Liver cells (most cells also) and catalyse the break down hydrogen peroxide made in cell reactions
Where is starch synthase found and what do they do
Plant cells and they catalyse the synthesis of starch from glucose
Where are DNA polymerase found and what do they do
Found in the nucleus and they catalyse the synthesis of DNA from its monomers
What does iodine do (testing foods)
Turns blue-black in the presence of starch (from yellow-orange)
How does Benedict’s solution work
When a food solution is mixed with Benedict’s solution and placed in a hot water bath, the colour changes from blue to red, indicating a lot of sugar (blue -> green -> orange -> red)
What happens in the biuret test
Potassium hydroxide is added to food solution
Two drops of copper sulfate added
Pale blue solution turns purple, indicating protein
What happens in the ethanol emulsion test
Food is mixed with ethanol and shaken, fats and oils float to the surface and a cloudy emulsion is forced when the mixture is left to stand
How can we measure the amount of energy in food
Burning it in a calorimeter
What is the active site
Area on an enzyme where the desired substrate fits (different enzymes have certain shapes because every enzyme can only work with specific substrates)
How can enzymes become denatured
By a change in pH or temperature, it can affect how the enzyme folds up.
What is diffusion
Diffusion is the movement of a substance from an area of high concentration to an area of lower concentration
What is osmosis
The movement of water molecules from a low to high concentration through a partially permeable membrane
What is active transport
Active transport is the movement of dissolved molecules into or out of a cell through the cell membrane against a concentration gradient, low to high concentration (requires energy as it is an active process)
How do you work out percentage change in mass
percentage change in mass = [ (final mass - initial mass) ÷ initial mass ] x100
