My Biology Notes

Created by

Ashwin Sivatheswaran

Cards (62)

Large surface area for faster diffusion
Many alveoli
Short diffusion distance for faster diffusion
Alveoli wall one cell thick
Capillary wall one cell thick
High concentration gradient for faster diffusion 
Many capillaries
Constant blood flow past alveoli
How is exhaled air different to inhaled air?
More carbon dioxide
Less oxygen
Why does the volume of the thorax increase during inhalation?
Diaphragm contracts and flattens
Intercostal muscles contract, so ribs move up and out
Why does air enter the lungs during inhalation?
Volume of thorax increases
So pressure in thorax decreases to below atmosphere pressure
Why does air leave the lungs during exhalation?
Volume of thorax decreases
So pressure in thorax increases to above atmosphere pressure
Why does the volume of the thorax decrease during exhalation? 
Diaphragm relaxes and moves up
Intercostal muscles relax so ribs move down and in
Why does breathing rate increase during exercise?
More oxygen in blood
More oxygen to muscle cells
More aerobic respiration
More ATP for muscle contraction
Less lactic acid produced
What happens to limewater when carbon dioxide is bubbled through?
Turns cloudy
What happens to hydrogen carbonate indicator when carbon dioxide is bubbled through?
turns from red to yellow
Trachea 
Single tube carrying air into the lungs
Bronchi 
two tubes that branch off of the trachea and lead to the lungs
Bronchioles 
smaller tubes which connect bronchi to alveoli
Effects of smoking on the lungs
Lung cancer
Increased infections, e.g. bronchitis
Smokers' cough - cilia damaged so mucus builds up
Emphysema - decreased surface area in lungs
How are lung infections prevented?
Mucus produced in trachea - traps bacteria
Cilia move and push mucus up and out of trachea
How does smoking affect the blood?
Carbon monoxide - binds irreversibly to haemoglobin, preventing oxygen transport
How does smoking affect the heart?
Damages the coronary arteries
Fat builds up in artery walls, causing narrowing
Clot can form, blocking blood vessel
No oxygen to heart muscle
Anaerobic respiration occurs
Lactic acid builds up
Kills heart tissue
What is the function of carbohydrates?
Used in respiration
To release energy for cell activities, muscle contraction and chemical reactions
What are the functions of proteins?
Transport substances, speed up reactions, structural support, make hormones
What are the functions of fats?
Store energy, protect vital organs, electrical and chemical insulation.
What are the functions of water? 
main part of cytoplasm, regulate temperature, lubricate joints, liquid for blood
What are the functions of dietary fibre?
Keeps food moving through the digestive system
Prevents constipation
What is the function of vitamin A? 
Helps form retinal cells
What is the function of vitamin C? 
wound healing, forms connective tissue (including blood vessel walls and gums)
What is the function of iron?
Needed to make haemoglobin for oxygen transport
What is the function of calcium?
It increases rigidity in bone and teeth etc.
It is used for blood clotting, muscle contraction, nerve transmissions,
What deficiency disease is caused by a lack of vitamin A?
Night blindness
What deficiency disease is caused by a lack of vitamin C?
Scurvy
What deficiency disease is caused by a lack of vitamin D?
Ricketts
What deficiency disease is caused by a lack of iron?
anaemia
What deficiency disease is caused by a lack of calcium?
osteoporosis
Where is DNA stored in a cell?
Nucleus
What is the role of the mitochondria?
Carry out respiration
What is the role of the chloroplasts?
Carry out photosynthesis
Which organelles are not found in animal cells but are in plant cells?
Chloroplasts, cell wall, vacuole
What is a plant cell wall made of?
Cellulose
What is a fungi cell wall made of?
Chitin
What is a gene? 
A section of DNA that codes for a protein
How many chromosomes do humans have?
46 (23 pairs)