Key Concepts Flashcards
Eukaryotic cell
Has a nucleus
Prokaryotic cell
Has no nucleus
Sub cellular structures in animal cell
Nucleus
Cell membrane
Mitochondria
Ribosomes
Sub cellular structures in plant cells
Nucleus Cell membrane Cell wall Chloroplasts Mitochondria Vacuole Ribosomes
Sub cellular structures in bacteria cell
Chromosomal DNA Plasmid DNA Cell membrane Ribosomes Flagella
Specialised cells examples
Sperm
Egg
Ciliates epithelial
How is sperm adapted
Acrosome
Haploid nucleus
Mitochondria
Tail
How is egg adapted
Nutrients in cytoplasm
Haploid nucleus
Changes in cell membrane after fertilisation
Light microscope
Uses light and it’s greatest possible magnification is around x2000
Electron microscopes
Uses electrons, can view object up to around x10 million
Why is electron microscope better
Can see cell structures and organelles more clearly
Pico
(10^-12)
Milli
(10^-3)
Nano
(10^-9)
Micro
(10^-6)
What are enzymes
Biological catalysts
Enzymes have to be _____ to their substrate
Specific
3 factors that affect enzyme activity
Temperature
Substrate concentration
pH
Why do enzymes have to be specific
So that the substrate is able to fit into the active site of the enzyme
What happens when an enzyme is denatured
The active site changes shape and therefore the substrate cannot fit
What happens with enzymes at low temperatures
Molecules move more slowly so the reaction is slower as it takes longer for the substrate to fit into active site
What is the optimum temperature
The point at which the enzyme works at its fastest rate
What does adding more substrate cause to happen
Increases rate of reaction
Why is there a limit to the amount of substrate that speeds the reaction
Eventually the active site of every enzyme will be busy
Optimum temperature for enzymes to work at (usually)
37C
Why does pH affect enzyme activity
Can change shape of active site
What is enzymes sole purpose
Break down large molecules into smaller ones, so they can be in the bloodstream
What enzymes digests carbohydrates
Amylase
What does amylase do
Digest carbohydrate (eg starch) into sugar (eg glucose)
Enzyme that digests lipids
Lipase
What does lipase do
Digest lipids (eg energy storage) into fatty acids/glycerol (eg for respiration)
What enzyme digests proteins
Protease
What does protease do
Digest protein (eg for muscle cells) into amino acids (eg to make enzymes)
What does it mean that an enzyme is a catalyst
It speeds up the reaction but is not used
What does iodine test for and how
Starch
If present - blue black
If not present - yellow/orange
What does Benedicts solution test for and how
Sugar
If present - green>orange>red (depend on how much sugar)
If not present - blue
Wha does biuret test test for and how
Protein
If present- pale purple
If not present- pale blue
What does ethanol test for and how
Fat
If present- cloudy
If not present - clear
What is diffusion
High concentration of molecules moves to a low concentration
Eg gaseous exchange
What is active transport
Low concentration of molecules to a high concentration
Eg roots absorb nutrients from soil
What is osmosis
Movement of water from high concentration to low
