2 i+h Flashcards
What two waste gases do plants produce and what processes produce them
- Oxygen (O2) is produced as a waste product of photosynthesis
- Carbon diovide (CO2) is produced as a waste product of respiration
3 Waste products produced in the body
- Urea
- Carbon dioxide
- Excess salt and water
3 excretory organs
- The lungs
- The kidneys
- The skin
2 reasons why unicellular organisms can rely on diffusion alone
- They have a large surface area to volume ratio due to their size
- They have low metabolic demands
What does the phloem transport
Sugars like sucrose and amino acids
What direction does the phloem transport sugars
The phloem tranpsort sugars up from leaves to each part of the plant
What does the xylem transport
water and minerals
What direction does the xylem transport water and minerals?
Up the plants (from the roots to the leaves)
How are root hair cells adapted to their function
- Long root hair extension to increase surface area for uptake
- Thin membranes to decrease the diffusion distance
3 benefits of traspiration
- the stream of water cools the plant
- the water helps to support the plant by creating turgor pressure
- the plant has a constant water supply for photosynthesis
How is the xylem adapted to transport water?
- It is waterproofed using a substance called lignin
- The xylem cells are dead and have no organelles so there is more space for water
4 components of the blood
- Red blood cells
- White blood cells
- Platelets
- Plasma
What is the function of platelets
Platelets are small fragments of cells that are involved in blood clotting
How are red blood cells adapted to their function?
- Contain haemoglobin to carry oxygen
- Biconcave shape to maximise surface area and allow them to squeze through capillaries
- No nucleus to maximise space for haemoglobin
What is the purpose of plasma?
Plasma is the liquid part of the blood
- its purpose is to act as a transport medium
- to transport CO2, hormones, nutrients and waste products.
What is the function of white blood cells?
White blood cells are involved in phagocytosis and some white blood cells produce antibodies.
What is a pathogen
A disease-causing microorganism
2 ways that the body can responf to detecting a pathogen
- Lymphocytes can produce antibodies that are specific to the antigens on the pathogen
- Phagocytes can engulf the pathogen
Describe the double circulatory system in mammals
The heart pumps blood to the lungs
- the oxygenated blood returns to the heart
- and is then pumped around the body
What is the difference in function between veins, arteries and capillaries?
- Arteries carry blood Away from the heart
- veINs carry blood towards (INto) the heart
- Capillaries flow close to tissues for exchange
Describe the structure of arteries
They have thick walls made of muscle and elsatic tissue
- and a small lumen to transport blood under high pressure
Descibe the structre of capillaries
They have thin walls about one cell thick to allow fot the easy exchange of substances at the tissues
Describe the structure of veins
Veins have less muscle and elastic tissue than arteries
- and they have a larger lumen as the blood is at lower pressure
- they also have valves to prevent backflow
Describe the blood flow through the right side of the heart
- Deoxygenated blood flows into the right atrium from vena cava
- This blood passes through the right AV valve into the right ventricle
- The blood is the pumped out of the heart to the lungs through the right SL valve or pulmonary valve and into the pulmonary artery
Describe the blood flow through the left side of the heart
- Blood enters into the left atrium from the pulmonary vein
- The bloof is then pumped through the left AV valve into the left ventricle
- The blood is then pumped out through the left SL valve and into the aorta
What is the name of the wall that separates the righ and left sides of the heart?
The septum
Name of artery that supplies the heart tissue with blood
coronary artery
What type of muscle is the heart made of
Cardiac muscle
Why is the wall of the left ventricle thicker than the wall of the right ventricle
The left ventricle has to pump blood a further distance around the whole body
- so the blood needs to be under a higher pressure
What does adrenaline do the the heart rate
Adrenaline increases the heart rate as it triggers the “fight or flight” reflex
2 parts of the body (aside heart) that adrenaline affects
- Adrenaline dilates the pupils
- Adrenaline increases the breathing rate
Why does the heart rate increase during exercise?
- More muscle movement requires more energy from respiration
- The muscle tissues need to be provided with a supply of oxygen to carry out respiration and so the heart needs to pump faster to provide the oxygen
What is the coronary heart disease (CHD)
When the artery providing the heart tissue with blood becomes blocked
3 common risk factors for CHD
- Smoking
- Poor diet
- Lack of exercise
