Triple & Further Science: Biology (III) Flashcards
What is osmosis?
Osmosis is the net movement of water molecules across a partially permeable membrane from a region of high concentration to an area of low concentration
What is diffusion?
Diffusion is the net movement of particles across a partially permeable membrane from a region of high concentration to an area of low concentration
How does water move into and out of cells?
Via osmosis – if cells are short of water the solution inside becomes concentrated drawing water in (and vice versa)
How are exchange surfaces adapted to increase diffusion?
Exchange surfaces are thin and have a large surface area
Where in plants do gases diffuse needed for life processes?
Leaves are adapted for gas diffusion: stomata are thin with a large surface area
Draw and label the human breathing system
Name and list the functions of the parts of the thorax (the top part of the body)
Oesophagus – food pipe
Trachea – windpipe
Intercostal muscles – allow the ribcage to move in/out
Heart – pumps blood around the body
Ribs – protect vital organs
Bronchi – splits from the trachea into each lung
Bronchiole – smaller tubes splitting from the bronchi
Alveoli – small air sacs
Diaphragm – muscle which contracts / relaxes forcing air in/out of lungs
What happens when we breathe in?
Intercostal muscles and diaphragm contract increasing thorax volume (decreasing pressure) drawing air in
What happens when we breathe out?
Intercostal muscles and diaphragm relax decreasing thorax volume (increasing pressure) forcing air out
What is ventilation and what are artificial ventilators?
Ventilation is the movement of air into and out of the lungs
Artificial ventilators help people who struggle to breathe on their own
How does gas exchange occur within the lungs?
Lungs contain millions of alveoli (air sacs) where gas exchange takes place (they have a very large surface area, are moist, have thin walls and a good blood supply)
How do villi help with absorption of digested food?
Villi are specialised cells in the small intestine which increase the surface area so digested food can be absorbed much quicker. They also have a single layer of surface cells and a good blood supply
What is active transport and where does it occur?
Active transport allows for substances to be absorbed against a concentration gradient (from a lower to higher concentration)
It occurs in the root hair cells to absorb water and minerals and in the gut (which takes a low concentration of nutrients and passes them into the blood which has a high concentration of nutrients)
What are phloem tubes?
Phloem tubes are made of living tubes and they transport food substances (in both directions)
What are xylem tubes?
Xylem tubes are made from dead cells and transport water and minerals from root to stem
What is the transpiration stream?
Transpiration is the loss of water from a plant
Why is the human heart known as a double circulatory system?
The heart pumps deoxygenated blood to the lungs to take in oxygen, then this blood returns and is pumped to the rest of the body
Draw a simple labeled diagram of the heart
What are the four chambers of the heart?
Right atrium – blood in from body
Right ventricle – blood to lungs
Left atrium – blood in from lungs
Left ventricle – blood to body
What are the three blood vessels?
Arteries
Veins
Capillaries
What do the arteries do and how are they specialised?
Arteries carry blood from the heart under a great pressure. They have thick walls and are elastic
What do the veins do and how are they specialised?
Veins carry blood back to the heart (low pressure) so have thinner walls, a large lumen and valves to keep the blood flowing in the correct direction
What do the capillaries do and how are they specialised?
Capillaries are one cell thick, pass close to every cell, have permeable walls allowing substances to diffuse in and out (e.g. O2, CO2, food, water, waste etc…) and have a small lumen
What is contained in the blood?
Red blood cells
White blood cells
Platelets
Plasma
What are the red blood cells?
Red blood cells carry oxygen – they have a large surface area, no nucleus and contain haemoglobin
What is the difference between haemoglobin and oxyhaemoglobin?
Haemoglobin combines with oxygen at the lungs to become oxyhaemoglobin – in body tissues this is reversed (releasing oxygen to the tissues)
What are the white blood cells?
White blood cells defend against disease – they consume microorganisms and produce antibodies and antitoxins