B2 Flashcards
What does the nucleus do
Controls the activities of the cell
What does the cytoplasm do
Where most chemical reactions take place
Function of the cell membrane
Control passage of substances in and out of the cell
Function of cell wall
Made of cellulose and strengthens the plant cell
Function of chloroplasts
Absorb light energy and where photosynthesis takes place
Function of permanent vacuole
Contains cell sap in plants
What is diffusion
Particles going from a high to low concentration
What do plant cells have that animal cells don’t
Vacuoles and chloroplasts and cell wall
Name three plant organs
Stems and roots and leaves
What does the xylem do
Transports water and mineral salts from the roots of the plant to stem and leaves
What is the role of the phloem
Transports sucrose and amino acids between leaves and other parts of the plant
Where are xylem and phloem located
Plant roots centre
Where is bile produced and stored
Produced in the liver and stored in the gall bladder
Why is it important for cultures on agar plates to not be contaminated
Could result in growth in pathogens
Suggest 2 ways you could prevent contamination of a culture in agar
Sterilise Petri dish and store the plate upside down
Why is it important that plates with cultures are stored at a certain temp
Reduce chance of growing harmful pathogens
What is used to test for protein
Biuret test
What is used to test for reducing sugars
Benedicts test
What is used to test for starch
Iodine test
What are the steps for testing for proteins
Grind up food you want to test, put sample into beaker with distilled water, stir with glass rod, filter mixture through a funnel lined with filter paper. Transfer 2cm^3 of filtered solution into test tube add 2cm^3 of biuret solution, shake and then it should turn pink/purple
How would you distinguish between two different glucose solutions
Add Benedictus solution to each test tube, then place them in water bath at 75•C and leave for 5mins. He should then look out for colour change and note which of a range of colours the solutions become
Why is the human circularity system described as double circularity system
Consists of two circuits joined together
How is heartbeat controlled
By a group of cells in right atrium wall that act as a pacemaker
How could you treat a disease where you have an irregular heart beat
Get an artificial pacemaker
How does an artificial pacemaker work
Produces an electric current to keep heart beating regularly
How are arteries adapted
Thick cell wall to make them strong and elastic fibres to allow them to stretch and spring back
How are white blood cells adapted
- Some can change shape to engulf microorganisms (phagocytosis)
- Others produce antibodies to fight microorganisms or antitoxins to neutralise any toxins produced by the microorganisms
How are red blood cells adapted for their function
Have a biconcave disc shape to give a larger surface area for absorbing oxygen. They don’t have a nucleus allowing for more room to carry oxygen
Describe the structure and function of platelets
Platelets are small fragments of cells with no nucleus they help the blood to clot at a wound
How can a blockage in coronary artery cause damage to patients heart muscle
Limits blood flow to heart muscle leading to a lack of oxygen reaching it
What can you use to treat blockages in the coronary artery
Stents
How do statins prevent/slow the progression of coronary heart disease
Reduce amount of bad cholesterol present in bloodstream
What is a way a valve may be faulty
Might not open fully
Why may an artificial heart be used
To keep patient alive while waiting for a donor heart
What is an advantage of using a natural donor heart over an artificial one
Blood flows smoother
