topic 1- key concepts in bio Flashcards
Difference between Eukaryotes and Prokaryotes
- eukaryotic cells are complex and include animal and plant cells
- prokaryotic cells are smaller and simpler e.g bacteria ( they’re single celled organisms)
What is found in Eukaryotic cells ( animal and plant)
Animal and plant cells
- Nucleus ( contains genetic information– DNA– of the cell and controls activities of cell)
- Cytoplasm (liquid substance in which chemical reactions occur and contains enzymes)
- Cell membrane (controls what enters and leaves the cell)
- Mitochondria (where aerobic respiration takes place - provides energy for a cell)
-Ribosomes ( Where protein synthesis occurs)
ONLY IN PLANT CELLS
- chloroplast ( Where photosynthesis takes place and contains chlorophyll that harvests light needed for photosynthesis)
- Permanent Vacuole ( contains cell sap, improves rigidity)
-Cell wall ( made from cellulose and strengthens cell
What is found in bacterial cells
- Cytoplasm
- Cell membrane
- Cell wall
- Chromosomal DNA ( bacterial cells have no nucleus- floats in cytoplasm)
- Plasmid ( small rings of DNA and code for extra genes)
- Flagellum ( Long, thin tails attached to bacteria that allows them to move)
What is a specialised cell?
- cell gaining new sub-cellular structures to be suited to its role
How sperm cell is specialised ?
-carry male’s DNA to the egg for reproduction
-Streamlined head and long tail to aid swimming
-Many mitochondria to supply energy to
allow cell to move
How egg cell is specialised ?
- specialised to accept single sperm cell and develop into embryo
- lots of mitochondria to provide energy source for developing embryo
- Large size and cytoplasm to allow quick, repeated division as embryo grows
How root cell is specialised ?
- have large surface area due to root hairs, meaning more water can move in
- large permanent vacuole affects the speed of movement of water from soil to the cell
- mitochondria provide energy from respiration for active transport of mineral ions into the root hair cell
How phloem cell is specialised ?
- Cell walls of each cell form structures called sieve plates when they break down, allows movement of substances from cell to cell
- lose many sub-cellular structures, energy cells need to be alive is supplied by mitochondria of the companion cells.
What are the two main types of microscopes ?
-light and electron
Magnification equation
magnification = image size/ actual size
Converting from milli, micro, nano and picometers
Milli x10^-3 divide by 1000 to get micrometers and etc.
Micro x10^-6
Nano x 10^-9
Pico x 10^-12
What is an enzyme ?
- biological catalyst speeds up rate of reaction
- fit in lock and key method– active site and substrate are complimentary
- form enzyme-substrate complex
What happens to an enzyme when it exceeds its optimum temp. ?
-becomes too hot bonds that hold enzyme together will break.
changes the shape of the active site, so the substrate can no longer ‘fit into’ the enzyme.
- denatured
What happens to an enzyme when pH is too high or low?
- forces that hold amino acid chains that make up the protein will be affected.
-change shape of active site, substrate can no longer
fit in. - denatured
Practical- when starch is present
- Place drop of iodine solution on each well of a tray.
- Label test tube with pH to be tested. Place in water beaker w/ 50ml water place above Bunsen Burner for 3 minutes.
3. 2cm3 amylase solution, 2cm3 starch solution and 1cm3 of buffer pH solution in test tube and start stopwatch. - After 10 seconds, use pipette to place a drop the solution into one well containing iodine solution if mixture turns blue-black starch is present & hasn’t yet been broken down.
- Repeat Step 4 after another 10 seconds, repeat until solution remains orange –record time taken
- control conc. and vol. of amylase solution
