Topic 1- Key Concepts Flashcards
A eukaryotic cell is…
A cell with a nucleus
Eg.animal and plant cells
A prokaryotic cell is…
A cell with no nucleus
Eg. Bacteria cell
Animal cell structures
Nucleus, cell membrane, mitochondria and ribosomes
Plant cell structures
Nucleus, cell membrane, cell wall, chloroplasts, mitochondria, vacuole and ribosomes
Bacteria cell structure
Chromosomal DNA, plasmid DNA, cell membrane, ribosomes and flagella
Nucleus
Controls the activity of the cell and controls DNA
Cytoplasm
A gel like substance where most chemical reactions occur
Ribosome
The site of protein-synthesis
Mitochondria
Where aerobic respiration takes place.
Respiration releases energy that allows the cell to work.
Cell membrane
A barrier around the cell which holds the cell together and controls what chemicals enter and exit the cell
Cell wall
Supports and strengthens the cell
Vacuole
Contains cell sap which keeps the gives the cell support and keeps the cell firm
Chloroplast
Site of photosynthesis which makes the plant food
Contains a pigment called chlorophyll which makes the plant green
Plasmid DNA
Contains genes for things like drug resistance
Flagellum
Moves the cell away from toxic substances and towards oxygen
Chromosomal DNA
Controls cells activity and replication
Sperm cell adaptations
Acrosomes…contains enzymes which digest the egg cell membrane
Nucleus…only contains 23 chromosomes (haploid)
Lots of mitochondria…provide energy in ATP form from aerobic respiration for the sperm to swim
Tail…to swim to the egg cell
Egg cell adaptations
Nucleus…only contains 23 chromosomes (haploid)
Nutrients in the cytoplasm…provides energy for the egg to grow and divide when fertilised
Cell membrane…changes when the first sperm enters the egg to prevent other sperm cells entering
Ciliates Epithelial cell adaptations
Cilia…hair like structures which move substances in the body, they. Are covered in cell membrane and contain strands of a substance that can contract and cause waves of movements
Eg. Lungs- move and waft mucus
Eg. Fallopian tubes (oviducts)- waft egg cells towards the uterus
Coarse focus
Moves the stage or to aid focussing
Fine focus
Moves the stage (small amounts) to aid focussing
Further down the microscope
Mirror
Reflects light from the light source up through the stage
Objective lens
Magnifies the specimen (makes the specimen appear larger)
Stage
Supports and positions the slide for focusing
Magnification equation
Magnification = image size / actual size
Another magnification equation
Magnification = length of scale bar / length the bar represents
Magnification calculations
1m/1000 = 1 millimetre 1mm/1000 = 1 micrometer CELLS 1ym/1000 = 1 nanometer (the micrometer symbol isn’t right) PARTS OF CELLS 1nm/1000 = 1 picometer
Magnification is…
Resolution is…
The degree to which the size of an image is larger than the object itself, expressed as X1000 etc.
The ability to see (two) objects (that are close together) as separate objects and see detail
Where do enzymes act in the digestive system
Mouth, stomach and small intestines
Why do only protease enzymes work in the stomach
Protease enzymes can tolerate a lower pH. The stomach has hydrochloric acid (to kill pathogens)
Why enzymes are needed for digestion
Enzymes break down larger food molecules (eg.lipids) into small molecules (eg.fatty acids and glycerol)
LOOK AT TESTING FOR BIOLOGICAL MOLECULES
Pg.19 IN REVISION GUIDE AND LOOK IN SCHOOLBOOK FOR TABLE TO HELP
Describe…
Increasing temperature effects on enzymes
As temperature increases the rate of reaction increases (include date temperatures if included)
The rate is optimum at …
Above the optimum temperature the rate of reaction decreases
Explain …
Increasing temperature effecting enzyme
This is because as the temperature increases enzymes and substrate molecules gain kinetic energy and successfully collide more frequently… this resulting in more enzyme substrate complex being formed and more products being made
After optimum temperature rate of reaction decreases because the increased temperature denatures the enzyme which means…
The active site has changed shape this means that no ESCs will form and no product will be made
Describe
Increasing pH effects enzyme
As pH increases the enzyme activity increases
The enzyme activity is optimum at
Above the optimum temperature the enzyme activity decreases
Explain …
Increasing pH effects enzyme
This is because as Ph increases fewer active sites are denatured, more ESCs from and more product is made
After optimum temperature the increasing pH causes the enzyme’s active site to denature and therefore fewer ESCs form and less product is made
Describe
Increasing substrate concentration effect on enzymes
As the pH substrate concentration increases the rate of reaction increases until an optimum substrate concentration of…
Above this optimum substrate concentration the rate of reaction stays the same/ does not change at the value of…
Explain…
Increasing substrate concentration effect on enzymes
This is because as the substrate concentration increases, more successful collisions occur between enzyme and substrate molecules which means more ESCs are formed and more product is made
At the point of saturation the rate of reaction is at a maximum because all the active sites are being used
Active transport is…
Substances move from a dilute to more concentrated solution (from low to high concentration)
Requires energy made from respiration in the mitochondria
Eg. Minerals taken into root hair cells from the soil
Diffusion is…
The movement of molecules from an area of high concentration to low concentration Doesn’t require energy Molecules move in random directions Happens in gases and liquids Osmosis is diffusion in water
Osmosis is…
The random movement of water molecules from an area high water potential to an area of low water potential through a partially permeable membrane
Osmosis in potatoes
Roughy, as the concentration of salt solution increases the change in mass also increased
Hypotonic is….
Isotonic is…
Hypertonic is…
…water solution-gain
…same water potential
…salt solution-loss
