Key concepts in Biology Flashcards
Define prokaryotic and eukaryotic cells.
prokaryotic - simple cells that DON’T have a nucleus
eukaryotic cells - complex cells that contain a nucleus
What subcellular structures are found in both animal and plants and explain their function.
- nucleus : contains genetic material of a cell so they control cell activity
- cytoplasm : gel like substance where all the organelles are and the chemical reactions take place
- cell membrane : controls what goes in and out of cell and holds it together
- mitochondria : where aerobic respiration takes place, releasing energy for the cell
- ribosomes : where protein synthesis takes place
what are subcellular structures found in plants ONLY
- chloroplasts : where photosynthesis takes place, providing food and contains green pigment called chlorophyll that harvests light
- permanent vacuole : contains cell sap and maintains internal pressure of the cell
- cell wall : made from cellulose to provide strength and support to the cell
what subcelluar stuctures are in bacteria and explain their functions
- cytoplasm
- cell membrane
- cell wall
- chromosonal DNA : one long loop of genetic material due to not having a nucleus so it controls activity and replication
- Plasmid DNA : small rings of DNA that provide extra genes
- Flagella : whip like tail that helps bacteria move
how have microscopes changed throughout the years?
what are the differences between electron and light microscopes?
Light microscope
- passes ought through specimen
- able to view large sub cellular structures like the nucleus
- able to study living things
Electron Microscope
- passes electrons through specimen
- has higher magnification and resolution -> see smaller things in detail
- allow better understanding of how cells work as u can see small sub cellular structures like ribosomes
- can only view dead cells
How do you prepare a slide for a microscopy?( CORE PRACTICAL)
what’s the equation for magnification?
Magnification - image size / actual size
Total magnification = eyepiece lens x objective lens
explain the mechanism of enzyme action
lock and key hypothesis :
- every enzyme has an active site that has a complimentary substrate that joins
- this forms an enzyme - substrate complex
- once this for,so reaction takes place and products are released from the surface of the enzyme (catalysts)
Identity and explain factors that affect enzyme activity
Increasing temperature
- as it increases, rate of reaction increases then rapidly decreases & stops
- above optimum temperature, bonds holding enzyme break which changes the shape of the active site
- the substrate can no longer fit the active sire -> DENATURED
CHANGING PH:
- if too high/too low forces holding enzymes are effected
- this changes shape of active site so it becomes measured
- optimum pH is often 7 but can change depending on conditions it’s produced (ex enzymes in stomach have pH of 2)
INCREASING SUBSTRATE CONCENTRATION :
- higher substrate concentration more likely to form enzyme substrate complexes
- occurs till the saturation point where there’s so many substrate molecules that enzymes don’t have any more active site
- then it does not affect rate of
Investigate the effect of pH on enzyme activity
- place single drop of iodine onto spotting tile
- Label test tubes with different pHs that are going to be tested
- Place water beaker onto a Bunsen burner till it reaches 35 degrees
- Use syringe to add 3cm3 of amalgse solution and 1cm of buffed pH solution to the boiling tube that’s in the beaker and wait for 5 minutes
- Use different syringe to add 3cm3 of starch solution to boiling tube
- Start sropwatch and mix content
- Do continuous sampling % use pipettes to get a bit of solution every 10 seconds and do an iodine test
- If startch is present then it will turn blue or black.
What’s the rate of calculation?
Rate = change / time
what are enzymes
Biological catalysts which speed up the reaction without affecting it
What’s enzyme specificity?
Enzymes can only catalyse if the substrate fits the active site
What’s the importance of enzymes as biological catalysts?
- larger molecules can be broken down into smaller compounds that can be used for growth and life processes
Why must large organic molecules be broken down into smaller molecules?
They’re to big to be absorbed across surface of gut wall
- broken down to be absorbed in to the bloodstream
