Organisation Flashcards
Define cells.
Building blocks of all living things.
Define tissues.
Group of similar cells working together to carry out a specific function.
Define an organ.
Different tissues working together to carry out a specific function.
Define an organ system.
Organs working together to carry out a specific function.
What happens in physical (mechanical) digestion?
Food is broken down into smaller pieces. This increases surface area of the food therefore facilitating chemical digestion by the enzymes.
Occurs in two ways:
- chewing action in mouth with help from the teeth.
- peristalsis = walls of the oesophagi, stomach and intestine.
There is no chemical change of food.
What happens in chemical digestion?
Breaking down of large insoluble molecules into smaller soluble molecules.
Enzymes are required so food is chemically changed.
What is the function of the gall bladder in the digestive system?
Stores bile before releasing it into the duodenum.
What is bile?
a substance produced by the liver. It emulsifies fats to prepare them for digestion.
What is the role of the mouth in digestion?
Food enters, physical digestion begins.
What is the purpose of salivary glands in the digestive system?
Produce saliva and amylase (breaks down starch)
What is the purpose of the oesophagus in the digestive system?
Transfers food to stomach from mouth by peristalsis.
What is the purpose of the stomach in the digestive system?
Mixes food with acid and enzymes - food broken down by acid and enzymes.
What is the purpose of the small intestine in digestion?
Absorbs nutrients and minerals from food. Also digests food using enzymes.
What is the purpose of the large intestine in the digestive system?
Absorbs water.
what is the purpose of the liver in the digestive system?
Creates bile which is then transported to the gall bladder. Liver also neutralises acid in the small intestine and emulsifies fat.
What are the food groups?
Carbohydrates Fats Proteins Minerals Vitamins Fibre Water
What are broken down carbohydrates called?
Simple sugars
Describe the chemistry of lipids.
They are made of 3 molecules of fatty acids and one molecule of glycerol. (The fatty acids three molecules can change but there will always be one molecule of glycerol.)
What is the subunit of proteins?
Amino acids.
What is the purpose of carbohydrates?
Energy to our bodies.
What is the purpose of fat?
Energy, insulate against cold
What is the purpose of proteins?
Growth and repair.
What is the purpose of minerals?
Help normal functioning of the body.
What is the purpose of vitamins?
Protect from sickness
What is the purpose of fibre?
Moves food down in the intestines.
What is the purpose of water?
Get rid of waste, needed for cells.
How do you test for starch?
Iodine drop solution
How do you test for simple sugars?
Blue Benedict’s solution
How do you test for protein?
Biuret
How do you test for lipids?
Ethanol
Define enzymes.
Biological catalysts that speed up a reaction.
What does every enzyme have?
An active site.
How many types of molecule can each enzyme break down?
Only one.
What is the first step of an enzyme cycle?
Substrate molecules move towards active site in the enzyme.
What is the second step of an enzyme cycle?
The substance fits into the active site.
What is the third step of an enzyme cycle?
Reaction occurs, products are made (molecule is broken down and split.)
What is the fourth and last step of an enzyme cycle?
Product molecules do not fit into the active site any more so they are released.
What is the difference between anabolic and catabolic enzymes?
Anabolic - building bigger molecules from smaller ones
Catabolic - breaking bigger molecules down into smaller ones
What us an optimum condition?
Conditions when an enzyme reaction is going as rapidly as possible.
What is the optimum temperature for enzymes?
40’C
What is the purpose of artery/vein/blood vessels?
Carry everything around the body
What is the purpose of red blood cells?
Transport oxygen
What is the purpose of white blood cells?
Fight infections
What is the purpose of plasma?
Transports nutrients, waste etc. around the body (carry everything except oxygen)
What is the purpose of platelets?
Blood clotting at injury sites
Define blood plasma.
A yellow liquid that transports everything you need around your body
What is blood made of?
55% plasma
<1% platelets and blood cells
45% red blood cells
How have red blood cells adapted to their function?
No nucleus => more space (maximise surface area)
Biconcave => faster oxygen (maximise surface area)
Lots of haemoglobin => binds to oxygen
How have white blood cells adapted to their function?
Some produce antibodies to kill invading microorganisms, other can engulf foreign bodies.
How have platelets adapted to their function?
No nucleus
Form a scab.
How have plasma adapted to its function?
It is largely water which can dissolve a wide range of substances
What is the purpose of a tough outer layer?
Resists pressure changes within and outside
What is the purpose of a muscle layer?
Contract to control blood flow
What is the purpose of the elastic layer?
Maintain blood pressure by stretching and springing back.
What is the purpose of the thin inner lining? (Endothelium)
Smooth (prevents friction), thin (allows diffusion)
What is the purpose of the lumen?
Central cavity through which the blood flows.
What are the walls of arteries like?
Thick with layers of muscles and elastic
What are the walls capillaries like?
Thin, single celled
What are the walls of veins like?
Thin elastic and muscle layers.
What is the direction of the flow of arteries?
Away from the heart.
What is the direction of the flow of the capillaries?
Through tissues
What is the direction of flow of the veins?
Towards the heart
Is the blood that flows through the arteries oxygenated or deoxygenated?
Oxygenated (except pulmonary arteries)
Is the blood flowing through the capillaries oxygenated or deoxygenated?
Oxygenated at the start, deoxygenated at the end.
Is the blood flowing through the veins oxygenated or deoxygenated?
Deoxygenated
Are valves present in arteries?
Not present
Are valves present in capillaries?
Not present
Are valves present in veins?
Present
What is the purpose of the right and left atrium?
Where blood collects to enter the heart (right atrium = deoxygenated,, left atrium = oxygenated)
Pump blood to the ventricles
What is the purpose of the right ventricle?
Pumps deoxygenated blood to the lungs
What is the purpose of the left ventricle?
Pump oxygenated blood around the body
What is the purpose of the valves?
Ensure that blood goes the right way.
What is a leaky valve?
Blood flows in the wrong direction and the heart is less efficient.
Give the advantages and disadvantages of mechanical valves and biological valves.
Biological valves:
Advantage=blood doesn’t clot
Disadvantage=needs to be replaces every ten years
Mechanical valves:
Advantage=more durable
Disadvantage=lifelong warfarin therapy to prevent clots
Where is the natural pace maker?
The right atrium
Where are artificial pacemakers found?
Implanted under skin where it connects with the right atrium and cures irregular heartbeats
What is the difference between respiration and breathing?
Breathing-the inhalation and exhalation of air
Respiration-the process by which we get energy from food. The food is in the form of glucose.
Where is he breathing system found?
In the thorax, protected by the ribs
What are the respiratory system and the digestive separated by?
The diaphragm
What happens when you breathe in?
Diaphragm contracts
Ribs go outwards
Intercostal muscles contract
Pressure increases
What happens when you breathe out?
Diaphragm relaxes
Ribs go inwards
Intercostal muscles relax
Pressure decreases
What are the adaptations of the alveoli?
- only one cell thick => easy diffusion
- covered by capillaries => gas pass almost directly between lungs and bloodstream
- moist => gas molecules easily dissolve
- large combined surface area => many gases exchanged with each breath.
What is the function and adaptation of the waxy cuticle and epidermis?
Function:
Reduces the rate of water loss from the leaf surface
Adaptation:
Large surface area
What is the function and adaptation of the palisade tissue?
Function:
Photosynthesis - light absorption
Adaptation:
Large vacuole and many chloroplasts
What is the function and adaptation of the spongy mesothelioma and airspaces?
Function:
Allow interchange of gases
Adaptation:
Large surface are and few chloroplasts
What is the function and adaptation of the guard cells?
Function:
Open and close stomata to regulate transpiration
Adaptation:
Allowing gas exchange and controlling water loss
What is the function and adaptation of stomata?
Function:
Holes in leaf to allow gases intake
(No adaptation)
What is the difference in flow of phloem and xylem vessels?
Xylem vessels: one way flow, water and minerals
Phloem vessels: two way flow, sugar
Define transpiration
Movement of water from roots to leaves.
Define translocation
Movement of sugar.
Are there any forces involved in translocation?
No forces are involved.
What method of diffusion does translocation use?
Active transport
What is xylem made of?
Dead cells
What is phloem made of?
Living cells
What is the cell wall of xylem made of?
Lignin
What are phloem cell walls made of?
Cellulose
Do xylem contain cytoplasm?
No
Describe phloem cell walls.
Permeable
What does the xylem transport?
Water and minerals
What does phloem transport?
Transports food
Is the xylem cell wall thick or thin?
Thick
Is the phloem cell wall thick or thin?
Thin
What way is the direction of flow of the xylem?
Upward
What is the direction of flow of the phloem?
Up and down
By which process does a leaf release oxygen during photosynthesis?
Diffusion
Define disease.
When there is something wrong with the body that has particular signs and symptoms depending on the type of disease.
Define health.
A state of physical, mental and social wellbeing, not just the absence of disease
Define communicable diseases.
Diseases caused by pathogens that can be passed from one organism to another
Define non communicable diseases.
Are not infections, not caused by other pathogens and cannot be passed from one organism to another
Define nicotine.
A powerful fast-acting and addictive drug which reaches your brain in seven seconds. It increases heart rate and raises blood pressure.
Define carbon monoxide.
A colourless poisonous gas found in high concentrations of tobacco smoke. When you inhale it enters your bloodstream and interferes with the working of your heart and blood vessels.
Define tar.
A sticky brown substance that forms when tobacco cools and thickens. It collects in your lungs and can cause cancer.
Define carcinogens.
Substances capable of causing cancer in living tissue.
What happens to cilia in the trachea when they are met with the chemicals in tobacco smoke?
They are anaesthetised.
What happens if you take in more energy than you need?
Energy turns into and is stored as fat.
What is the formula for Body Mass Index?
Mass in kg/(height in m)^2
CAN NOT BE USED ON CHILDREN
Define cirrhosis.
When the liver hasn’t been able to do its job because the intake of alcohol is too high.
What does alcohol do to the brain?
Causes the brain to shrink. Also causes less brain activity.
