Paper 1 Flashcards
(56 cards)
Explain cell differentiation
Happens during an organisms development
Organisms start as one cell
They divide to form embryos that differentiate (specialise) to produce cells that can perform all of the body’s functions
Plant cell differentiation
Many plant cells keep their ability to differentiate throughout their life
Because of this, plants are always able to create new tissues
Adult animal cells differentiation
Cell differentiation is rare in mature (adult) animals
Their cells mostly divide in order to replace cells and repair tissues
New tissues are rarely created.
Soerm cell adaptations
Sperms cells are specialised to perform a specific function.
Acrosome - the acrosome at the tip of the head contains an enzyme needed to penetrate into an egg cell
Middle section - filled with mitochondria to carry out respiration and provide/release energy it needs to travel long distance to egg cell.
Head - contains nucleus (carries one half of an organisms genetic material) . Combines with egg cells genetic material to fertilise egg.
Tail - allows sperm to swim to egg
Nerve cell specialisation
Axon - increases distance that electrical signals can travel
Part of the cell that electrical signals travel along
Surrounded in meylin sheath (insulated nerve cell)
this stops electrical nerve signals leaking out of the nerve cell.
This increases speed of transmission of electrical signals
Dendrites - branches of a nerve cell.
Several dendrites spread outwards from the cell body to transfer electrical impulses to other neurones.
Gaps between neurons are called synapses.
Muscle cells specialisation
Specialised to perform a specific function
Contain lots of mitochondria to generate lots of energy for motion
Protein fibres within the cell can contract, so it can move
Root hair cell specialisation
No chloroplasts as they are located underground and there is no light for photosynthesis.
Long projections ti increase surface area that rhe plant can use to absorb water and minerals.
Xylem specialisation
Xylem vessels are made up of a series of connected dead xylem cells.
The end walls of the dead cells are broken to allow water to move through.
Lignin (a substance) strengthens the cell walls of xylem cells
Why are xylem cell’s end walls broken?
To allow water and dissolved minerals to move through
Phloem specialisation
Phloem specialised to transport food up and down plant through columns of alive cells.
Have small holes in end walls to allow food products to move up and down the phloem vessels throughout the plant.
Cell cycle explain
Initial growth stage:
Extra ribosomes, mitochondria and other sun cellular structures are produced.
The cells chromosomes (made of DNA) are replicated so there are 2 sets of the cells chromosomes.
Mitosis:
The 2 sets of chromosomes are pulled to opposite ends of the cell.
Then the nucleus divided in 2.
Cell divides:
2 identical cells are created by the division of the cytoplasm and cell membranes.1
Stem cells are found in:
Plant meristems (plant stem cells are found in the meristem tissue, and can differentiate into most into all types of plant cell throughout plant life, this is what allows plants to grow their whole lives).
Bone marrow (with human adults only).
Embryos (stem cells found in embryos can differentiate into most cell types, to produce all cell types needed to make up an organism).
How can stem cells be used
-To repair damaged organs or bones or cartilage
-To help treat diseases (e.g. brain cells for Parkinson’s disease)
-Repair immune systems
-Reverse paralysis
Where are digestive enzymes made and released
In the glands abd lining if the gut.
They are then released out of body cells into the digestive system.
What can be used to test for lipids and what will happen if lipids are present
Lipids - Sudan III
If lipids are present, solution will go cloudy
What do digestive enzymes do to large insoluble molecules
Catalyse the breakdown of large insoluble molecules into smaller soluble molecules, so they can be dissolved into the bloodstream.
What can be used to test for sugar and what will happen if sugar are present
Sugar - Benedict’s reagent and heat up for two minutes.
Turns red if sugar is present.
Color depends on concentration.
What can be used to test for starch and what will happen if starch are present
Starch - Iodine solution
Will turn blue/black if starch is present
What can be used to test for protien and what will happen if protein is present
Protein - Biuret Solution
Will turn purple is proteins are present.
Explain coronary heart disease
Build up of fatty deposits/ cholesterol in the coronary artery’s
This causes less flow of blood ti the heart muscle
So the heart muscle gets less flow of oxygen
Consequences?:
Less respiration being carried out by the heart
Person may have trouble breathing
Could put strain on the heart
Treatments of coronary heart disease
Statins
Drugs you can take to decrease blood cholesterol levels. This slows build up of fatty materials
- have side effects
Stents
Device inserted into coronary artery and inflated to keep it open.
Over time, because I of irritation caused by the stent, the artery can begin to narrow as scar tissue builds up.
Drugs must be taken to prevent blood clotting in the stent.
What are the benefits of artificial hearts
Unlikely to be rejected by immune system, so immunosuppressant drugs are unnecessary
Can also provide heart with rest to help it recover
Negatives of artificial hearts
Result in long and expensive stays at the hospital.
Can cause blood clotting, leading to strokes.
Advatages and disadvantages of statins
Advantages :
Cheap
Disadvantages :
may have side effects
Patient has ti remember to take them
