Biology - From Big to Small Flashcards
Nucleus
Controls the activity of the cell (by making proteins)
Contains the chromosomes - strands of DNA which carry the genes (each gene codes for a protein)
Cell membrane
Boundary between the cytoplasm and the cell’s surroundings. Controls what substances enter and leave the cell
Cytoplasm
Jelly-like liquid where chemical reactions occur
Mitochondria
Carries out some reactions of aerobic respiration, producing ATP (energy carrier molecule)
Ribosomes
Synthesise (assemble) proteins from amino acids
Chloroplasts
Absorb light energy and use it to carry out the chemical reactions of photosynthesis, making biological molecules for plant cells
Cell wall
Made of cellulose (a carbohydrate) in plants. Helps to keep plant cells in a fixed shape (and so keeps the plant upright)
Vacuole
Filled with a watery liquid called cell sap; stores dissolved sugars, mineral ions and other substances
Which of the 5 kingdoms are multicellular?
Plants and animals
Cells
This is the smallest functional unit of life that contains a number of organelles, structures that carry out specific processes the cells need to survive
Tissues
These are groups of similar cells which work together to carry out the same function (job)
Example of tissues
Human muscle tissue
Organs
These are made of several different tissues working together to carry out a more complex function
Example of organs
In humans, muscle is one of the tissues making up the heart organ
Organ systems
These are made up of several difference organs working together to carry out a complex function essential to life
Example of organ systems
Circulating blood around the body
What is the level of organisation in the body?
Atoms, molecules, organelles, cells, tissues, organs, organ systems and the human (organism)
What chemical is used to test for simple sugars like glucose?
Benedict’s Solution
How is Benedict’s solution used to test for simple sugars?
Mix with the food sample in a test tube and heat for 5 minutes in a hot water bath.
What colour changes occur with Benedict’s solution if sugars are present in the samples you are testing?
A range of colours depending on the concentration of sugars e.g. Blue (none), green/yellow (traces of reducing sugar), orange/red (moderate), brick red (large amount of reducing sugar)
What chemical is used to test for starch?
Iodine solution
How is iodine solution used to test for starch?
Add a few drops of it with a food sample in a test tube
What colour changes occur with iodine solution if starch is present in the samples you are testing?
Light orange/brown if not present or black/blue if present
What chemical is used to test for protein?
Biuret solution
How is Biuret solution used to test for protein?
Add 2cm³ water and shake it to a food sample in a test tube, add an equal volume of dilute potassium hydroxide and shake again, then add two drops of 1% copper sulphate solution
What colour changes occur with Biuret solution if
protein is present in the samples you are testing?
Blue if not present or pale/purple if present
What chemical is used to test for fats?
Ethanol emulsion
How is ethanol emulsion used to test for fats?
Add 2cm³ water to the food sample in a test tube, add a small volume of absolute ethanol and shake, add an equal volume of water
What colour changes occur with ethanol emulsion if fats are present in the samples you are testing?
Colourless if not present or milky-white if it present
