topic 1 - key concepts in biology Flashcards
What are eukaryotic cells
Animal and plant cells
What do animal cells contain and their functions
Nucleus - holds genetic information
Cell membrane - holds the cell together and what goes in and out
Mitochondria - powerhouse of the cell
Ribosomes - protein synthesis
Cytoplasm - gel l8e substance where chemical reactions happen
What do plant cells contain and their functions
Nucleus – hold genetic material
Cell membrane – holds cell together and control what goes in and out
Mitochondria – powerhouse of the cell
Vacuole – contain cell sap, maintains the internal pressure to support cell
Ribosomes – side of protein synthesis
Cell wall – made of cellulose, supports the cell and strengthens it
Chloroplast – photosynthesis occurs, contains a green substance called chlorophyll
What do bacteria cells contain and their functions
Chromosomal DNA – controls the cells activities and replication, it flows free in the cytoplasm
Ribosomes
Cell membrane
Plasmid DNA – small loops of extra DNA that aren’t part of the chromosome
Flagella – a long hair like structure that rotates to make the bacteria move
What are the two specialised cells?
Sperm and egg ciliated epithelial cells
How are sperm cells adapted to the function
Acrosome – stores enzymes needed to digest its way through the membrane of the egg cell
Haploid nucleus
Mitochondria – provide energy needed to swim
Tail – it can swim to the egg
How are egg cells adapted to function?
Nutrients in the cytoplasm for feeding embryo
Haploid nucleus
Changes of structure to stop more sperm getting in after fertilisation
How are ciliated epithelial cells adapted to their function?
Have Celia on the top of the surface cell to move substances along the surface of the tissue
Changes in microscopes
Like microscopes were invented in the 1590s they work by passing light through the specimen. They let us see things like nuclear and chloroplast and we can also use them to study living cells.
Electron microscopes were invented in 1930s they use electrons rather than light. Electron microscopes have a higher magnification and resolution than light microscopes, so they let us see much smaller things in more detail like the internal structure of mitochondria and chloroplasts.
What is order of units
Milli
Micro
Nano
Pico
Core practical microscopy
Use a thin slice of your specimen
Take a clean slide and use a puppet to put one drop of water in the middle of it – this will secure the specimen in place. The new tweezers to place your specimen on the side.
at a drop stain if your specimen is completely transparent or colours
Place a cover slip at one end of the specimen holding it at our angle with a mounted needle and carefully lower it onto the slide. Press it down gently so that no air bubbles are trapped under it. Then click the slide onto the stage.
Select the lowest powered object
Use the course adjustment knob to move the stage up so that the IPS, move to stage downwards until the specimen is nearly in focus
Then adjust the focus with the final adjustment knob until you get a clear image
What is the equation for total magnification?
Eye piece lens magnification X objective lens magnification
Wha5 is the equation for magnification
Image size divided by real size
How do enzymes work?
Every enzyme has a active site – the part where it joins onto its substrate catalyse the
Enzymes usually only work with one substrate. They are to have a high specific for the sub
This is because, for the enzyme to work, the substrate has to fit into the active site. If the substrate shape doesn’t match the active side shape, then the reaction will be catalysed.
How can enzymes be denatured?
If an enzyme reaches its optimum pH, temperature then it can start to denature this changes the active site and won’t be able to fit into the substrate anymore and it will not catalyse the reaction
How does substrate concentration affect enzyme activity?
Substrate concentration also affects the rate of reaction – the higher substrate concentration, the faster the reaction. This is because it’s more likely that the enzyme will meet up and react with a substance molecule.
Investigating pH on enzymes - core practical
put a drop of iodine solution into every well of a spotting tile
Play some Bunsen burner on a heat proof mat and a tripod and goes over the Bunsen burner. Put a beaker of water on top of the tripod and heat the water until it is 35°C. Try to keep the temperature of the water constant throughout the experiment .
use a syringe to add 3 cm³ of Amla solution and 1 cm³ of a buffer solution with a pH of 5 to a boiling tube. Using test powders, put the boiling tube into the beaker of water and wait for five minutes.
next use a different syringe to add 3 cm³ of a start solution to the boiling tube.
immediately makes the contents of the boiling tube and start a stop clock.
when are you doing? Solution? Remains brownie orange, starch is no longer present.
repeat the whole experiment with both of the solutions at different PH values to see how pH affect a time taken for the start should be broken down
What is the calculation for rate?
1000 divided by time
What does the enzyme carbohydrate breakdown?
Convert carbohydrates into simple sugars
What does proteins convert?
Proteins convert proteins into amino acids
What does lipases convert?
Lipids into glycerol and fatty acid
What is diffusion and how does it transport substances?
Diffusion is the net movement of particles from the area of high concentration to an area of lower concentration
Only very small molecules can diffuse through cell membranes
What is osmosis and how does it transport substances?
I suppose that movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
Things like water can pass through
He tries to even up the concentration either side of the membrane
What is active transport and how to transport substances?
Active transport is the movement of particles across a membrane against the concentration gradient
it requires energy
