PAPER 1 GCSE Flashcards
Factors affecting the rate of diffusion
- Surface Area : Volume- if surface are is large compared to the volume, the rate of diffusion will be faster
- concentration gradient
- distance (travelling a shorter distance)
- temperature (particles move quicker with a higher temperature)
What is diffusion
Diffusion is when particles spread from an area of high concentration to an area of low concentration. The particles move along a “concentration gradient” and this process uses no energy
What is active transport
Active transport uses energy to move substances against their concentration gradient.The energy comes from respiration
What is osmosis
Osmosis is the net movement of water molecules from an area of high water potential to an area of low water potential across a permeable membrane
Diffusion in non living organism experiment
- Place a few potassium permanganate crystals in a beaker of water.
- Note the colour of the water after a period of time eg. 15 minutes.
- Note the colour of the water after a longer period of time eg. 1 hour.
Osmosis in a non living organism experiment
- Tie one end of a visking tube with a piece of string.
- Pour some solution into the visking tube.
- Insert a capillary tube into one end of the visking tubing.
- Use a marker to mark the initial water level in the visking tubing.
- Immerse the visking tubing in a beaker of distilled water.
- Note the difference in water level in the capillary.
Osmosis in living organism experiment
- Accurately measure and record the mass of each potato cylinder.
- Measure sugar solution and put into boiling tube
- Repeat for other concentrations of the solution and distilled water into boiling tubes
- Add one potato cylinder (of known mass) to each boiling tube.
- Leave the cylinders in the boiling tubes for at least 15 minutes in a test tube rack.
- Measure the mass of each cylinder and record your measurements in the table. Calculate
the percentage changes for each cylinder.
What is the trachea
Tube lined with rings of cartilage
Goes from the mouth to the lungs where it splits
The cartilage prevents the trachea from collapsing
What are the ribs
Bones that protect the lungs from damage - the ribcage can expand or contravt eith breathing
What are the bronchi
The two tubes that the trachea split into
They have cadtilage rings to lrevent them from collapsing
What are the bronchioles
The small tubes that come from the bronchi that have alveoli on the end
What are alveoli
Small air sacs at the end of the bronchioles
What are the pleural membranes
Very slippery to help reduce the friction of the lungs rubbing along the inside of the ribcage
Action of intercostal muscles when humans inhale
External intercostal muscles contract and make the ribcage lift upwards and outwards
Actions of intercostal muscles when humans exhale
External intercostal muscles relax
Internal intercostal muscles can be contracted consciously to expel air faster
Action of diaphragm when inhaling
Diaphragm contracts
It flattens out and moves downwards
This increase the volume of the thorax (chest cavity)
The air pressure decreases inside the thorax
The air pressure outside the lungs is higher and moves into the lungs
Action of diaphragm when exhaling
Diaphragm relaxes
Forms a dome shape and moves upwards
This decreases the volum eof the chest cavity (thorax)
Air pressure increases inside the thorax
Air pressure inside the lungs is higher and so moves out of the lungs
How are alveoli adapted for gas exchange by diffusion
- alveoli are small and have a large surface area to volume ratio
- walls of alveoli are one cell thick to allow for faster diffusion
- capillaries are very close to the alveoli fo allow a short diffusion pathway
- inside of alveoli is lined with a surfactant that sfops ghd alveoli from collapsing and also allows oxygen and co2 to diffuse through
How can smoking cause coronary heaft disease
- nicotine causes the blood pressure to increase
- this can damage the lining of the arteries
- the damaged arteries can start to have fatty deposits build up in the damaged areas
- these can block the arteries leading to the heart causing less oxygen to reach the heart cells so they cannot respire and die
Experiment to show the effect of exercise on breathing
Measure the number of breaths per minute at rest
Exercise for a set amount of time
Measure fhe breathing rate directly after the exercise
Measure breathing rate every minute after exercise until if reaches back to normal breathing rate
How do unicellular organisms move substances in and out of the cell
Diffusion
Unicellular organisms have large surface area to colume ratio
Substances (nutrition and oxygen) can more easily diffuse into or out of the centre of the cell
Why do multicellular organisms rely on transport systems
Large multicellular organisms have smaller surface area to volume ratios than unicellular organisms
Cells deep inside the organism camnot recieve nutrients and oxygen fast enough to survive without a transport system
A transport system allows nutrients and pxygen to reach every cell and also allows waste to not build up and become toxic
What is transported in the phloem
Sucrose and amino acids between the leaves and other parts of the plant
What is transported in the xylem
Water, nitrates and magnesium ions from the roots to other parts of the plant
What does the plasma transport
Carbon dioxide, digested food, urea, hormones and heat energy
How are red blood cells adapted to their function
- biconcave shape to increase surface area to volume ratio to help oxygen diffuse more quickly
- no nucleus to make more space for haemoglobin to carry more oxygen
- haemoglobin is present to carry oxygen
How do phagocytes respond to disease
Phagocytes - ingest / engulf pathogens and use digestive enzymes to kill them
How do lymphocytes respond to disease
Produce antibodies that bind to a specific pathogens antigens
These can kill pathogens or cause pathogens to clump together so that they can more easily be engulfed by phagocytes
Through which blood vessels does oxygenated blood flow
Aorta, pulmonary vein, coronary arteries
Through which blood vessels does deoxygenated blood flow though
Vena cava, pulmonary artery
What do the coronary arteries do
Provide oxygenated blood and nutrients to the cardiac muscles
Why is the left ventricle wall thicker that the right
So that it produces a higher blood pressure so it can pump blood further around the body
What is the role of the valves
Prevents back flow of blood so it can flow in one direction
Advantages of a double circulatory system
Under higher pressure so can supply oxygenated blood further and helps organism with higher metabolisms and higher rates of respiration by supplying more oxygen faster
Why does heart change increase during exercise
Muscles contract more meaning that more respiration occurs
More oxygen is needed so the heart rate increases to supply the extra oxygen to the muscles
How is an artery adapted for its function
Thick elastic and muscular walls to withstand high blood pressure
Lumen is smaller to maintain high blood pressure
Artery function
To transport oxygenated blood around the body
How is the vein adapted for its function
Has thinner walls as there is a lower blood pressure
The lumen is larger and veins have valves
Role of veins
To transport deoxygenated blood back to the heart
How is a capillary adapted for its function
Lumen is only one red blood cell thick
Walls are one cell thick to allow a short diffusion distance
Capillaries role
To allow the exchange of gases in the lungs and in the body
What is homeostasis
The maintenance of a constant internal environment
What is a stimulus
A change in the surroundings of an organism that produces a response
What is a receptor
A cell or organ that detects a stimulus
What is an effector
An organ that brings about a response (a muscle or gland)