B2 Flashcards
What is the definition of a cell?
Basic building blocks of all living organisms
What is a tissue?
A group of cells with similar structures and functions
What is an organ?
Groups of tissues performing specific functions
What are organ systems?
Organs organised into organ systems to work together to form organisms
What is an enzyme?
Proteins that act as a biological catalyst
How do digestive enzymes work?
They convert food into small soluble molecules that can be absorbed into bloodstream
What enzyme breaks down carbohydrates?
Carbohydrates (amylase) break down carbohydrates into simple sugars
What enzyme breaks down proteins?
Protease break down protein into amino acids
What enzyme breaks down lipids?
Lipase breaks down lipids into glycerol and fatty acids
What is the function of bile?
Bike (which is made in the liver) neutralises hydrochloric acid from the stomach
What is the heart?
An organ that pumps blood around the body in a double circulatory system
Why is it called a double circulatory system?
The right ventricle pumps blood to the lungs where gas exchange takes place. The left ventricle pumps blood around the rest of the body
What is heart rate controlled by?
The natural resting heart rate is controlled by a group of cells located in the right atrium that act as a pacemaker.
What are the four chambers of the heart?
Right atrium, right ventricle, left atrium, right ventricle
How does blood travel through the heart?
Blood flows into atria in heart from pulmonary vein and vena cava.
Atria contract and push blood into ventricles.
Ventricles contract, blood is forced into pulmonary artery and aorta, out of the heart
What is a catalyst?
A substance which increases the speed of a reaction without being changed or used up
What are the characteristics of an enzyme?
They all have an active site that is complimentary to its substrates
What happens to enzyme activity if temperature is too high?
The enzymes active site will change shape and the enzyme will become denatured
What is meant by an optimum pH level?
The pH level at which the enzyme works best at
What is the food test for sugars?
Benedict’s solution added to a food sample, warm in a water bath, if positive colour change from blue to brick red
What is the food test for starch?
Add iodine solution to food sample, if positive colour change from orange to blue black
What is the food test for proteins?
Add biuret solution to food sample, if positive colour change from blue to purple
What is the food test for lipids?
Add ethanol to food sample, shake, white emulsion appear if a positive test
What are the functions of an artery?
Carry blood away from heart
What is the function of a capillary?
Involved in exchange of material
What is the function of a vein?
Carry blood back to heart
What are the features of an artery?
Walls are strong and elastic
Walls are thick- High blood pressure
A small lumen
Thick layer of muscle
Have elastic fibres
What are the features of a capillary?
Arteries branch into capillaries
Really thin
Close to every cell
Permeable walls
Supply food and oxygen, take away CO2
Only one cell thick - short diffusion distance
What are the features of a vein?
Thin walls- lower blood pressure
Bigger lumen
Valves- prevent back flow of blood
What is the order of the digestive system?
Salivary glands
Oesophagus
Stomach
Liver
Gall bladder
Pancreas
Large intestine
Small intestine
Rectum
Where are each enzyme produced?
Amylase: salivary glands, pancreas, small intestine
Protease: stomach, pancreas, small intestine
Lipase: pancreas, small intestine
What does the large intestine do?
Absorb excess water from the food
What are the four components of blood?
White blood cells, red blood cells, platelets, plasma
What is the function of white blood cells?
They defend against infection
How do white blood cells defend against infections?
Production of antitoxins and antibodies
Phagocytosis
What is the function of platelets?
Help blood clot
What is the function of red blood cells?
Carry oxygen
What is the function of plasma?
Carry everything inside of blood:
‘everything’ is all components, nutrients, carbon dioxide, urea, hormones, proteins, antibodies and antitoxins
What is coronary heart disease?
A build up fat inside the coronary arteries that results in a lack of oxygen for the heart
How is coronary heart disease cured?
Stents, statins, heart transplants
What is a stent?
A small metal mesh tube that is used to inflate the artery in order for blood to flow through freely.
What are statins?
A drug that is used to reduce blood cholesterol levels which slows down the build of plaque.
What are the consequences of faulty valves?
A leak may develop which creates a strain on heart and can lead to heart failure, heart attack or a stroke.
How are faulty heart valves replaced?
Using biological or mechanical valves
What is meant by a mechanical valve?
Made of metal or carbon and designed to work like regular valves
How can patients survive while on the waiting list for a new heart?
Using an artificial heart.
What is main risk of a transplant?
Rejection
What is health?
The state of physical and mental well being
What are factors that affect health?
Disease (communicable and non-communicable) diet, stress, life situations
What is meant by communicable disease?
Diseases that is spread between person to person:through contact. E.g. measles,malaria
What is meant by a non communicable disease?
Cannot be spread between person to person e.g. cancer
Why are people with immune system problems more likely to suffer from communicable diseases?
Their body is less likely to be able to defend itself against pathogens
How can so,e types of cancer be triggered?
Infection that comes from certain viruses
What is an example of a virus that can causes cancer?
Infection with HPV which causes cervical cancer
What is obesity a risk factor for?
Type 2 diabetes
How does the amount of alcohol correlate with the risk of liver and brain function?
Too much alcohol can lead to liver disease and can affect brain function as it damages nerve cells in the brain
What diseases does smoking cause?
Smoking directly causes cardiovascular and lung diseases/cancer.
How does smoking cause disease?
Damages the walls of arteries and cells in the lining of the lungs
How does smoking/drinking while pregnant affect an unborn baby?
It can cause lots of health problems to the unborn child
What causes cancer?
Uncontrolled cell growth and division which results in the formation of tumours
What are two types of tumours?
Benign and malignant
What is it meant by a benign tumour?
A tumour that isn’t cancerous and remains in the same place in the body
What is meant by a malignant tumour.
A cancerous tumor that spreads throughout the whole body
What life style factors can increase the risk of cancer?
Smoking, obesity, UV exposure, viral infections
What type of cancer does UvV radiation increase the risk of?
Skin cancer
How are genetics associated with the risk of cancer?
Some genes that are more susceptible to cancer can be inherited
What are the types of plant tissue?
epidermal
tissues
palisade mesophyll
spongy mesophyll
xylem and phloem meristem tissue
What is the epidermal tissue?
Covers the plant
What are the features of the epidermal tissue?
Covered in a waxy cuticle to reduce water loss by evaporation
What is the palisade mesophyll?
Where most photosynthesis happens
What are the features of the palisade mesophyll?
Lots of chloroplasts and near top of leaf to get most light
What is the spongey mesophyll tissue?
Contains big air spaces so gas can diffuse in and out of
What are xylem and phloem?
Transport water, minerals and food around plant
What are the features of xylem and phloem?
They form a network of vascular bundles
What is meristem tissue?
Able to differentiate into different types of plant cells
What are the features of Meristem tissue?
(Roots and shoots)
Stomata that are controlled by guard cells
How are the stomata helpful?
They let carbon dioxide diffuse directly into the leaf
How do guard cells know when to open and shut the stomata?
They respond to environmental conditions
What do phloem tubes transport?
Food
How many directions does the transport in phloem tubes travel in?
Both (two)
What is the name for the process of transporting food in plants?
Translocation
What is the material called that strengthens xylem tubes?
Lignin
What do xylem tubes carry?
Water and mineral irons
What direction does the water travel in xylem tubes?
Upwards the water starts from the roots and travels through the xylem out through the leaves
What is the process of water moving up the xylem tube called?
Transpiration
What is transpiration caused by?
Evaporation and diffusion of water
What is transpiration affected by?
Light intensity
temperature airflow
humidity
How does light intensity affect transpiration rate?
The bride of the light to the greater the transpiration rate
How does temperature affect the transpiration rate?
The warmer is the faster the transpiration happens
How does airflow affect the transpiration rate?
The best of the airflow around the leaf the greater transpiration rate
How does humidity affect the transpiration rate?
The drier the air around the leaf the faster transpiration happens
