1 CELLS, BIOLOGICAL MOLECULES, ENZYMES + KINGDOMS Flashcards
Role of nucleus
Controls activity of cell by making proteins, and contains chromosomes
Role of cell membrane
Controls what enters and leaves the cell (selectively permeable)
Role of cytoplasm
Chemical reactions occur
Role of mitochondria
Carried out aerobic respiration
Role of ribosomes
Synthesise proteins from amino acids
Role of chloroplasts
Carry out photosynthesis
Role of cell wall
Keeps cells fixed in shape (made of cellulose)
Role of vacuole
Watery sap that stores dissolved sugars, mineral ions and other substances
What organelles are in a plant cell
Cytoplasm, chloroplast, nucleus, ribosomes, mitochondria, cell wall, cell membrane, vacuole
What organelles are in an animal cell
Cell membrane, mitochondria, ribosomes, cytoplasm, nucleus
Chemical composition of carbohydrates
Carbon, hydrogen and oxygen
Storage carbohydrate in plants
Starch
Storage carbohydrate in animals and fungi
Glycogen
Why are starch and glycogen better storage molecules than simple sugars
Less soluble, so have less effect on water movement in and out of the cells
Chemical composition of lipids
Carbon, hydrogen and oxygen
Structure of a fat cell
Glycerol backbone with 3 fatty acids
Structure of a carbohydrate
Lots of simple sugars like glucose
Chemical composition of proteins
Carbon, hydrogen, oxygen and nitrogen
Structure of a protein
A variation of 20 amino-acids in any order
Describe the test for reducing sugars (glucose)
- Add benedict’s solution to a samle of food in solution
- Place in water bath at 80c for 5mins
- Blue to brick red
- Green, yellow and orange are positive, but in low concentration
Test for starch
- Add few drops of orange iodine solution to a sample on a spotting tile
- A blue-black colour indicates starch
Test for protein
- Add water to sample to form solution
- Add equal volume of potassium hydroxide and shake
- Add two drops of 1% copper sulfate solution
- A pale purple colour will develop
Test for lipids
- Add small volume of absolute ethanol and shake
- Add equal volume water
- A cloudy white colour will form
Define a catalyst
A chemical that increases the rate of reaction, without being used up in the reaction itself
Describe how an enzyme works
- Substate and enzyme collide
- Substrate binds to active site of enzyme
- The reaction occuring means the products no longer fit the active sites shape and so are released
- The enzyme is free to catalyse the next reaction
How does an increase in temperature affect the rate of an enzyme controlled reaction
- As temperature increases, the rate increases until an optimum temperature has been reached
- Gives enzymes and substrates more kinetic energy
- Move faster and collide more often
- Too hot, and enzyme denatures, and active site changes shape
- Substate cannot bind to active site and reason cannot occur
How does too high/low pH affect the rate of an ezyme controlled reaction
- pH change changes shape of enzyme
- Become permenantly denaturesd
- Active site changes shape, so substrate is no longer complementary to the substrate and reaction cannot occur
What characteristics do all living organisms share
- Move
- Respire
- Respond to surroundings
- Homeostatis
- Grow
- Reproduce
- Excrete
- Nutrition
Cell wall of plant
Cellulose
Carbohydrate storage of a plant cell
Starch
Carbohydrate storage of an animal cell
Glycogen
Organisation of a fungi
Thread like hyphae make up a mycelium
Cell wall of fungi
Chitin
How do fungi feed
Saprotrophic nutrition
Carbohydrate storage of fungi
Glycogen
Pathogenic protoctista
Plasmodium
What kingdoms can be pathogens
Fungi, bacteria, protoctista or virus
Describe the levels of organisation in organisms
- Organelles
- Cells
- Tissues
- Organs
- Organ systems
Name a pathogenic protoctist and what disease it causes
Plasmodium causes malaria
Describe how an enzyme works
- Substate and enzyme collide
- Substrate binds to active site of enzyme
- The reaction occuring means the products no longer fit the active sites shape and so are released
- The enzyme is free to catalyse the next reaction