What are cells in terms of organisation?
The basic building blocks of all living organisms
What is a tissue?
A tissue is a group of cells with a similar structure and function
What are organs?
Aggregations of tissues performing specific functions
What is the function of enzymes?
Catalyse specific reactions in living organisms due to the shape of their active site.
What do digestive enzymes do?
Digestive enzymes convert food into small soluble molecules that can be absorbed into bloodstream
What do carbohydrase break down? And what into?
Carbohydrases break down carbohydrates to simple sugars
What is amylase?
Amylase is a carbohydrase which breaks down starch into sugar (maltose)
What do proteases do?
Proteases break down proteins to amino acids
What do lipase do?
Break down lipids to glycerol and fatty acids
What are the products of digestion used for?
To build new carbohydrates, lipids and proteins. Some glucose is used in respiration
Where is bile made?
In the liver
Where is bile stored?
The gall bladder
What is the function of bile?
It is alkaline to neutralise hydrochloride acid from the stomach. It also emulsified fat to form small droplets which increase the surface area. The alkaline conditions and large surface area increase the rate of fat breakdown lipase
Put these in order Tissues Organisms Organ systems Cells Organs
Cells tissues Organs Organ systems Organisms
Meaning of insoluble
Cannot dissolve
Meaning of soluble
Can dissolve
Definition of enzyme
A biological molecule that speeds up a chemical reaction
What is digestion?
The break down of large insoluble molecules into small soluble molecules so that they can be absorbed by the body. This is brought about by enzymes.
Where teeth and chewing breaks food into smaller chunks to increase surface area for action by the enzymes
??
What is it
Mechanical digestion
What is the heart?
The heart is an organ that pumps blood around the body in a double circulatory system
Where does the right ventricle pump blood?
To the lungs where gas exchanges take place
Where does the left ventricle pump blood?
Around the rest of the body
Name three different types of blood vessel
Arteries
Veins
Capillaries
What is the natural resting heart rate controlled by
A group of cells in the right atrium that acts as a pacemaker
What is an articulate pacemaker
Electrical devices used to correct irregularities in the heart rate
What is blood
Blood is a tissue consisting of plasma, in which red blood cells, white blood cells and platelets are suspended
What is coronary heart disease?
In Coronary heart disease layers of fatty material build up inside the coronary arteries, narrowing them. This reduces the blood flow through the coronary arteries, resulting in a lack of oxygen for the heart muscle.
How are stents used to treat coronary heart disease?
Stents are used to keep the coronary arteries open
How are statins used to treat coronary heart disease?
Statins are widely used to reduce blood cholesterol levels which slows down the rate of fatty material deposit
What is a faulty valve?
In some people heart valves may become faulty, preventing the valve from opening fully, or the heart valve might develop a leak.
How can faulty valves be replaced
Using biological or mechanical valves
What can be done in the case of heart failure
A donor heart or heart and lungs can be transplanted
How is a sperm cell specialised?
Has a tail to propel the sperm to fertilise egg
Acrosome contains enzymes to allow the sperm to penetrate the outer layer of the egg
Have extra mitochondria to provide energy for their journey
How is a muscle cell specialised?
Protein fibres that can contract
Many mitochondria for energy
How are xylem cells specialised?
Xylem cells are arranged ends to end but the end walls break down to form hollow tube
Cell wall strengthened by lignin
How are phloem cell specialised?
The end walls of the cells allow sugars through but support the tubes
Have companion cells
How is a root hair roll specialised?
Lots of mitochondria for active transport of minerals
Long projection to increase surface area to absorb water and minerals
Name the components to the digestive system
Mouth Oesophagus Liver Stomach Gall bladder Pancreas Large intestine Small intestine Rectum Anus
What is the active site of an enzyme?
A space within the protein molecule called the active site
They work best at a specific temperature and pH called the _____________
Optimum
What is the ‘lock and key theory’?
A model used to explain how enzymes work: the chemical that reacts is called the substrate (key) and it fits into the enzymes active site (lock)
What is denaturing?
When high temperatures and extremes of pH make enzymes change shape
Why can and enzyme not work after being denatured?
The substrate cannot fit into active site
Where is amylase produced?
Is produced in the salivary glands and the pancreas
Where is protease produced?
Stomach
Pancreas
Small intestine
Where is lipase produced?
Pancreas and small intestine
How do you test for sugar?
Add Benedictus reagent and heat in a water bath for two minutes. If sugar is present it will turn red.
How do you test for starch?
Add iodine solution. If it is present it will turn blue/black
How do you test for protein?
Add biuret reagent . If protein is present it will turn purple
What does plasma transport around the body?
Various chemical substances such as the products of digestion, hormones,
Antibodies,urea and carbon dioxide
What do red blood cells contain?
Haemoglobin
What is haemoglobin?
It binds to oxygen to transport it from lungs to the tissues and cells which need it for respiration
How is the red blood cell adapted for its role?
Very small so they can fit through tiny capillaries
Biconcave shape to give them large surface area that oxygen can quickly diffuse across
Do not contain a nucleus so there is more room for haemoglobin
How are white blood cells adapted for their roles?
Help to protect the body against infection
Can change shape, so they can squeeze out of the blood vessels into the tissues it surround and engulf microorganisms
What are platelets?
Fragments of cells which has collect at wounds and trigger blood clotting
What do arteries do?
Take blood from your heart to your organs
What do veins do?
Take blood from your organs to your heart
What do capillaries do
Allow substances needed by cells to pass out of blood and allow substances produced by cells to pass into blood
How are arteries adapted for their functions?
Thick walls made from muscle and elastic fibres to deal with blood surges
How are veins adapted?
Thinner wall and valves to prevent back flow
How are capillaries adapted for their role?
Narrow thin walled blood vessels
How many times does the blood pass through the Heart on each circuit
Twice
Name the four chambers in the heart and what they do?
The left and right arteries which receive blood from veins
The left and right ventricles which pump the blood out of arteries
What is the valves purpose
Make sure blood flows in the correct direction
What are the stages of the cardiac cycle?
Blood enters through the atria
The atria contact and force blood into ventricles
The ventricles contact and force blood of the heart
How are alveoli adapted for efficient gas exchange?
They have a large moist surface area
Very rich blood supply
Short diffusion distance because thy are close to capillaries
The trachea divides into two tubes called __________
Bronchi
The bronchi divide to form _________
Bronchioles
The bronchioles divide until they end in tiny air sacs called ________
Alveoli
What is the pulmonary artery unusual
Unlike other arteries it carries deoxygenated blood
Why is the pulmonary vein different to other veins?
It carries oxygenated blood
What is oxyhemoglobin?
The name given to the substance formed when haemoglobin in your red blood cells bind with oxygen
What is health?
The state of physical and mental well-being
What factors affect health?
Disease Diet Stress Life situations On both mental and physical health
Defects in the immune system mean that an individual is more likely to suffer form i__________ d_________
Infectious disease
Viruses living in cells can be the trigger for c________
Cancers
Immune reactions initially caused by a pathogen can trigger allergies such as s_______ r_________ and a________
Skin rashes
Asthma
Severe physical health can lead to d_________ and other mental illness
Depression
What can cause cardiovascular disease?
Diet
Smoking
Exercises
What can effect liver and brain function?
Alcohol
What can have effect on lung disease and lung cancer?
Smoking
What can effect unborn babies?
Smoking
Alcohol
What are risk factors of cancer?
Carcinogens
Including ionising radiation
What are benign tumours?
Growths of abnormal cells which are contained in one area, usually within a membrane. They do not invade other parts of the body.
What are malignant tumours?
They are cancers. They invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours.
What kind of risk factors cause cancers?
Both lifestyle and genetic can cause cancer
What is obesity a risk factor for?
Type 2 diabetes
What are the costs of the problems developed from risk factors?
Personal- loss of life
Financial- NHS treatment
What is a risk factor?
Increase the likelihood of developing a disease
What is the epidermis function?
Covers the outer surfaces of plant for protection
What is palisade mesophyll function?
Main site of photosynthesis in plant
What is spongy mesophyll function?
Air spaces between the cells allow gases to diffuse through the leaf
Xylem vessels function
Transports water and minerals through plant, from roots to leaves. Also supports the plant
Phloem vessel function
Transports dissolved food material through the plant
Meristem tissue function
Found mainly at the tips of the roots and shoots, where it can produce new cells for growth
What do plant tissues gathered together form?
Organs
Is the leaf a plant organ?
Yes
How is the structure of the palisade mesophyll related to it function?
Many chloroplasts to the top of leaf to trap maximum sunlight
How is the mesophyll structure related to its function?
Lots of air spaces to allow gases to diffuse
What do the stomata allow?
Diffusion of gases in and out of leaf and can be opened and closed by guard cells
How does water enter the plant?
From the soil through the root hair cells by osmosis
What does water contain when it enters plants?
Dissolved minerals
How is the water transported after it has entered the cell?
Xylem vessels from the roots to the stems and leaves
What will most of the water do when it reaches the leaves?
Evaporate and diffuse out of the stomata
What is the loss of water called in a plant?
Transpiration
Name 4 factors that affect the rate of transpiration
Temperature
Air flow
Light intensity
Humidity
How does temperature affect transpiration?
Increase in temperature will increase the rate as more energy transferred to the water to allow it to evaporate
How does airflow affect transpiration?
Faster airflow will increase the rate as it will blow away water vapour allowing more to evaporate
How does light intensity affect the rate of transpiration?
Increased light intensity will increase the rate, as it will cause stomata to open
How does humidity affects rate of transpiration?
Increased humidity decrease rate as it contains more water vapour, so concentration gradient for diffusion lower
At night are the stomata open or closed? Give a reason for your answer
Closed
Carbon dioxide not needed for photosynthesis, so closing them will reduce water loss
How do stomata open?
When water is plentiful, guard cells take up water and bend. Causes stomata to open, so gases for photosynthesis are free to move in and out of the stomata along with water from transpiration
How do stomata close?
When water is scarce, losing water makes the stomata change shape and close. This stops the plant from losing more water through transpiration
What is translocation?
When phloem tissue transport dissolved sugars from the leaves to the rest of the plant
