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B1 - Key Concepts in Biology - Coggle Diagram
B1 - Key Concepts in Biology
What are the 2 different types of Cells ?
Prokaryotic
Chromosomal DNA: Contains Genetic Information for a prokaryote
Plasmid DNA: Contain Genetic Information that can spread between bacteria, allowing for genetic varation
Cell Membrane: Controls what enters and leaves the cell
Ribosomes: Where the Bacteria can produce proteins
Flagella: Used for movement in the bacteria
Eukaryotic
Animal Cells
Nucleus: Controls the cell and contains all genetic information
Cell Membrane: Controls what enters and leaves the cell
Mitochondria: Where Energy is released, where respiration occurs
Ribosomes: Where the process of translation in protein synthesis occurs
Cytoplasm: Where Chemical Reactions Occur
Plant Cells
Nucleus: Controls the cell and contains all genetic information
Cell Membrane: Controls what enters and leaves the cell
Cytoplasm: Where Chemical Reactions Occur
Mitochondria: Where Energy is released, where respiration occurs
Ribosomes: Where the process of translation in protein synthesis occurs
Vacuole: Support and strengthen the plant cell
Cell Wall: Supports and Strengthens the cell
Chloroplasts: Contain a chemical called chlorophyll which allows for photosynthesis
Different types of Specialised Cells
Sperm Cell
Acrosome: Digestive Enzyme for breaking the membrane around the egg cell for fertilization
Haploid Nucleus: A nucleus that contains half the amount of chromosomes, and allow for genetic variation
Mitochondria: Energy needed for swimming to the Egg
Flagella: Acts as a tail allowing for the movement of the sperm cell to the egg cell
Egg Cells
Nutrients in Cytoplasm: Means that the zygote can develop
Haploid Nucleus: A nucleus that contains half the amount of chromosomes, and allow for genetic variation
Changes in Cell Membrane After Fertilization: This ensures that no more sperm cells can fertilize the cells
Ciliated Epithelial Cells
Made up of Cilia and lump up together mucus containing potential pathogens, that can later be put through the digestive system
How has changes in Microscope Technology help the development of the model of the cell?
The Inventions of more and more magnified telescopes combined with the increasing resolutions of these images would allow for scientists to see cells but also see sub cellular structures. The development of the light microscope would allow for the development of the general model of the cell, whilst the invention of the electron microscope would allow scientists to see the sub cellular structures like ribosomes with more detail
What are the relative sizes of the different cells?
Plant cells and Animal (Eukaryotic) cells have similar sizes, with animal cells being approximately between 10 - 30 micrometres and plant cells having the approximate size of 10 - 100 micrometres
However, Bacteria Cells (Prokaryotic) are approximately between the sizes of 0.1 to 0.5 nanometres
What are the quantitative units used most commonly when studying cells?
Units
pico (10−12)
nano (10−9)
micro (10−6)
milli (10−3)
Enzymes
Enzymes contain 3 different parts
Enzyme: Catalyses the reaction
Substrate: The substance that is being broken down or built up
Active Site: Where the substrate is broken down or built up
Factors that can affect Enzymes?
Temperature
An Enzyme also has a optimum temperature, usually 36-38 degrees Celsius, if the temperature is too low, the rate of enzyme activity will be less active but if its too high, the enzyme will denature
Substrate Concentration
The higher the substrate concentration the higher the rate of reaction, but if there is too much, the rate of reaction will plateau as there isn't enough enzymes to form enzyme-substrate complexes
pH
A enzyme has an optimum pH, if the pH is too low or too high, the enzyme will denature, decreasing the rate of enzyme activity
Enzymes: Specificity
Lock and Key Mechanisms: Enzymes are very specific and will only bind with a specific substrate, this is called the lock and key mechanism
Enzymes can also denature due to changes in the shape of the active site
Practical: Effects of pH on Enzyme Activity
This Experiment uses amylase to catalyse the breakdown on start into maltose. We can detect starch using iodine solution (starch is present it will turn from brownie-orange to blue-black)
Steps
Set up a Bunsen burner, heatproof mat, tripod and gauze.
Place a beaker of water on the gauze and adjust the flame to keep the water at about 35°C.
Now put two drops of iodine solution into each spot of a spotting tile.
Add 2 cm3 of amylase enzyme solution to a test tube.
Place 2 cm3 of starch solution into the same tube.
Finally add 1 cm3 of pH solution to the tube. This will keep the pH constant.
Mix the solution in the test tube and place it into the beaker of water on the Bunsen burner.
Use a pipette to remove a few drops of solution every 20 seconds from the test tube and put them into a different well of the spotting tile.
Repeat until the iodine solution stops turning black.
Record the time this takes.
Repeat with different pH solutions.
Rate of Reaction:
rate = 1000/time
What breakdowns what?
Carbohydrates are broken down by carbohydrase into sugars
Proteins are broken down by proteases into amino acids
Lipids are broken down by lipase into fatty acids and glycerol
Chemical Reagents:
Fats
Emulsion Test
Shake a test tube containing substance with ethanol for a minute
If Lipid is present, there will be a milky precipitate
Reducing sugars
Benedict's Reagent
Colour change from blue to brick red
Starch
Iodine Test
Blue-Black if Starch is present
Brownie-Orange if Starch isn't present
Protein
Biuret Test
no protein = blue
protein = purple
Osmosis, Diffusion, Active Transport
Diffusion: the movement of particles from an area of high concentration to low concentration
Active Transport : The movement of particles against a concentration gradient
Osmosis:: The movement of water particles across a semi-permeable membrane from a area of high concentration to low concentration
Percentage change in mass = final mass - inital mass / inital mass * 10-0