RAG Rated - RED Flashcards
Test for Sugar
Benedict’s Reagent - add it to a sample and heat it to a water bath that is at 75C. If positive, the test will change from blue to brick red.
Test for Proteins
Biuret Test - add drops of Potassium Hydroxide solution to make the solution alkaline. Then add some copper sulphate (blue). The solution will stay blue if no protein, however it will turn purple if there is
Lipids/fats test -
Emulsion Test - Shake the test substance with ethanol for around a minute until it dissolves, then pour the solution into the water. If lipids are present, they will precipitate and the solution will show as a milky emulsion.
Starch test -
Add iodine solution. If starch is present, then the solution changes from brown-orange to blue-black. If nothing, it stays brown-orange.
Catalyst
A substance which increases the speed of the reaction without being used up or changed in the reaction.
Active Transport
The movement of particles across a membrane against a concentration gradient using energy transferred during respiration.
Osmosis
The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
Interphase
The cell is growing and the number of sub-cellular structures (ribosomes/mitochondria) is increasing. The DNA of the cell is duplicated. X-Shaped chromosomes are formed.
Prophase
The chromosomes condense, getting shorter and fatter. The membrane around the nucleus breaks down and the chromosomes lie free in the cytoplasm.
Metaphase -
The chromosomes line up at the centre of the cell.
Anaphase
Spindle fibres pull the chromosomes apart. The chromatids line up at opposite ends of the cell
Telophase -
Membranes form around each of the sets of chromosomes. These become the nuclei of the new cells.
Cytokinesis
The cytoplasm and cell membrane divide to form two new, genetically identical diploid sex daughter cells.
Stem Cells
These are undifferentiated cells.
Embryonic stem cells
Can divide and produce any kind of cell. Stem cells are important for growth and development.
Adult stem cells
Used to replace damaged cells.
Stem cells in medicine - Advantages
Sickle cell anaemia can be cured with a bone marrow transplant. Extracting stem cells from embryos and growing them into specialised cells. Creating specialised cells to replace those which have been damaged by disease or injury.
Disadvantages of stem cells
Rejection - If not grown using the patient’s own stem cells, the patient’s body may recognise the cells as foreign and trigger an immune response to try and get rid of them.
Tumour development - If scientists cannot control the rate of division, then a tumour can develop.
Disease transmission - If donor stem cells are infected with a virus, then it could be passed on to the recipient and make them sicker.
Ethical issues of stem cells
Human embryos shouldn’t be used because each one is a potential human life. However some think that curing people who are alive is more important than potential life.
The Nervous System
Made up of neurones (nerve cells) which go to all parts of the body.
Stimuli
- The body has lots of sensory receptors (cells that detect a change in the environment AKA a stimulus).
- When a stimulus is detected by receptors, the information is converted to a nervous (electrical) impulse and sent along sensory neurones to the CNS (brain+spinal cord).
Neurones - have….
- All have a cell body with a nucleus.
- The cell body has Extensions that connect to other neurones.
- Neurones can be long which speeds up the impulse.
The CNS
- The CNS co-ordinates the response. Impulses travel through the CNS along relay neurones.
- The CNS sends information to an effector (muscle or gland) along a motor neurone. The effector then responds - muscle contracts or gland secretes hormone.
Reaction time
The time taken to react to a stimulus is your reaction time.