Organisation Flashcards
What are the basic building blocks of all living organisms?
Cells
Cells are the fundamental units of structure and function in living organisms.
What distinguishes unicellular organisms from multicellular organisms?
Unicellular organisms are made from one cell, whereas multicellular organisms are made up of collections of cells.
What is the role of specialised cells in multicellular organisms?
They carry out particular functions, forming tissues, which form organs in organ systems.
What are two examples of organ systems in humans?
- Digestive system
- Respiratory system
What is the primary function of the digestive system?
It provides the body with nutrients.
What organ is responsible for churning food and producing protease enzymes?
The stomach
What is the function of protease enzymes?
They digest proteins into amino acids.
What is the significance of stomach acid?
It provides a suitable pH for enzymes and destroys pathogens in food.
What types of tissues are found in the stomach?
- Glandular tissue
- Muscle tissue
- Epithelial tissue
What is the role of the mouth in digestion?
Food is ingested and mechanically digested by teeth.
What does the oesophagus do?
Connects the mouth to the stomach and uses peristalsis to move food downwards.
What is the function of bile produced by the liver?
It aids in the digestion of fats and neutralises stomach acid.
What is the role of the pancreas in digestion?
It produces amylase, protease, and lipase enzymes.
Where does the absorption of food and water occur in the digestive system?
In the small intestine.
What happens to remaining water in the large intestine?
It is absorbed into the blood, and solid waste forms faeces.
What is egestion?
The process of expelling faeces from the body via the anus.
What role do bacteria play in digestion?
They help break down substances, supply essential nutrients, and provide competition against harmful bacteria.
What are enzymes?
Biological catalysts made from protein that speed up chemical reactions.
What is metabolism?
The sum of all reactions happening in a cell or organism.
What happens when substrates bind to the active site of an enzyme?
A chemical reaction occurs, forming products that are released.
What is the lock and key model in enzymology?
It describes how enzymes and substrates fit together perfectly for a reaction.
What is enzyme specificity?
The ability of an enzyme to catalyse only one particular reaction.
What is denaturation in enzymes?
The process where an enzyme loses its shape and function, usually due to high temperatures or extreme pH levels.
What is the optimum temperature for enzyme activity in the human body?
Around 37°C.
What effect does increasing temperature have on enzyme activity?
It increases activity up to the optimum temperature but can lead to denaturation beyond that.
What is the optimum pH for most enzymes?
7, but some enzymes have different optimal pH levels.
Fill in the blank: Amylase is an enzyme that digests starch into _______.
maltose
What is the aim of the required practical study involving amylase?
To investigate the effect of pH on the rate of reaction of amylase.
What is used as an indicator to test for the presence of starch?
Iodine solution.
What happens to iodine solution when starch is present?
It turns blue-black.
True or False: Once enzymes are denatured, they can regain their proper shape.
False
What is the purpose of digestion?
To break down large, insoluble molecules into smaller, soluble molecules that can be absorbed into the bloodstream
What are enzymes?
Biological catalysts that speed up chemical reactions without being used up or changed in the reaction
Name the three main types of digestive enzymes.
- Carbohydrases
- Proteases
- Lipases
What do carbohydrases do?
Break down carbohydrates to simple sugars
What is amylase?
A carbohydrase that breaks down starch into maltose, which is then broken down into glucose by maltase
Where is amylase produced?
- Salivary glands
- Pancreas
- Small intestine
What is the function of proteases?
Break down proteins into amino acids
Where does protein digestion take place?
In the stomach and small intestine
What is the role of lipases?
Break down lipids (fats) into glycerol and fatty acids
Where are lipases produced?
In the pancreas and secreted into the duodenum
What are the two main roles of bile?
- Neutralises hydrochloric acid from the stomach
- Emulsifies large drops of fat
What is emulsification?
The process of breaking down large drops of fat into smaller ones, increasing surface area
What are the products of digestion used for?
- Building new carbohydrates
- Building new lipids
- Building new proteins
What safety precautions should be taken during the food tests?
- Wear goggles due to hazardous reagents
- Wash hands immediately if chemicals get onto skin
- Keep ethanol away from open flames
What color change indicates a positive result in the Benedict’s test?
A color change from blue to brick red
Fill in the blank: The enzyme _______ breaks down starch into maltose.
amylase
True or False: The pancreas is directly involved in the passage of food.
False
What is the function of bile in the digestive process?
To neutralise stomach acid and emulsify fats
What is the significance of the alkaline conditions created by bile?
Allows lipase to chemically break down fat faster
What are the end products of lipid digestion?
- Glycerol
- Fatty acids
What is the role of amino acids post-digestion?
Used to build proteins like enzymes and antibodies
What is the function of glucose released from carbohydrate breakdown?
Used in respiration to release energy
What are the adaptations for gas exchange in the lungs?
Features include:
* Large surface area
* Thin walls
* Good ventilation
* Good blood supply
These adaptations increase the efficiency of gas exchange.
What is the primary process through which gas exchange occurs?
Diffusion
Breathing maintains high concentration gradients for oxygen and carbon dioxide.
How many alveoli are approximately present in each lung?
250 - 300 million alveoli
Total surface area of each lung is around 70m².
What components make up the human circulatory system?
Components include:
* Blood vessels
* A pump (the heart)
* Valves
These maintain a one-way flow of blood around the body.
What is the function of the right side of the heart?
Pumps deoxygenated blood to the lungs for gas exchange
This is referred to as the pulmonary circuit.
What is the function of the left side of the heart?
Pumps oxygenated blood under high pressure to the body
This is known as systemic circulation.
What are the benefits of a double circulatory system?
Benefits include:
* Maintains high pressure for systemic circulation
* Allows more time for gas diffusion in the lungs
Blood loses pressure in the pulmonary circuit, enhancing gas exchange.
What are the two types of valves in the heart responsible for?
Preventing backflow of blood
The heart has a septum that separates deoxygenated and oxygenated blood.
What is the role of the pacemaker in the heart?
Coordinates the contraction of the heart muscle
It regulates the heart rate.
What happens to the heart rate during exercise?
Heart rate increases to meet higher oxygen demand
The pacemaker sends out electrical impulses more frequently.
What are artificial pacemakers used for?
To correct irregularities in the heart rate
They are implanted devices that deliver electrical currents to the heart.
What are the three types of blood vessels?
Types include:
* Arteries
* Veins
* Capillaries
Each type has a specific function in the circulatory system.
What is the structure of arteries designed for?
To withstand and maintain high pressures
They have thick walls with collagen, smooth muscle, and elastic fibers.
What is the primary function of capillaries?
Links arteries to veins and facilitates gas exchange
Capillary walls are one cell thick to minimize diffusion distance.
What is blood primarily composed of?
Consists of plasma, red blood cells, white blood cells, and platelets
Plasma is largely water with dissolved substances.
What is the function of red blood cells?
Transport oxygen via the protein hemoglobin
They have a biconcave shape to maximize surface area for gas exchange.
How do white blood cells function in the immune system?
Defend the body from infection by:
* Engulfing pathogens
* Producing antibodies
* Neutralizing toxins
Phagocytes and lymphocytes are key types of white blood cells.
What is the role of platelets in the blood?
Involved in forming blood clots to prevent blood loss
Insufficient platelets can lead to life-threatening bleeding.
Fill in the blank: The _______ is the only artery in the body to carry deoxygenated blood.
Pulmonary artery
Fill in the blank: The _______ is the only vein in the body to carry oxygenated blood.
Pulmonary vein
True or False: The walls of capillaries are thick to support high blood pressure.
False
Capillary walls are thin to minimize diffusion distance.
What is coronary heart disease (CHD)?
Coronary heart disease involves layers of fatty material (plaque) building up inside the coronary arteries, reducing blood flow and oxygen to the heart muscle.
What is the role of the coronary arteries?
The coronary arteries supply the heart with oxygenated blood.
What happens if a coronary artery is partially blocked?
Partial blockage creates restricted blood flow to the cardiac muscle cells, resulting in severe chest pains called angina.
What is the result of a complete blockage in a coronary artery?
Complete blockage means cells in that area of the heart will not be able to respire aerobically, leading to a heart attack.
What is a stent?
A stent is a narrow tube used to keep the coronary arteries open by increasing the width of the lumen.
What are the advantages of using stents?
- Effective at reducing the risk of a heart attack
- Last a long time
- Simple minor surgery to insert
What are the disadvantages of using stents?
- Risk of blood clots occurring
- Risk of infection during surgery
- Risk of damage to the blood vessel during surgery
What are statins?
Statins are drugs that reduce levels of fatty deposits (cholesterol) in the blood by blocking an enzyme in the liver.
What are the advantages of statins?
- Reduce levels of ‘bad’ cholesterol (LDL)
- Increase levels of ‘good’ cholesterol (HDL)
What are the disadvantages of statins?
- Need to be taken regularly and long-term
- Take time to have an effect
- Side effects include muscle pain, kidney problems, neurological issues
What role do heart valves play?
Heart valves ensure blood is pumped from the ventricles to the arteries in a one-way direction.
What can cause faulty heart valves?
Faulty heart valves can result from illness, old age, or a heart attack.
What types of valves can be used for replacement?
- Biological valves from cows or pigs
- Mechanical valves
What are the advantages of biological valves?
- Highly effective
- Less likely to leak
- Long-lasting
What are the disadvantages of biological valves?
- Need to be replaced after 12-15 years
- Risk of immune rejection
- Can increase the likelihood of blood clots
What are the advantages of mechanical valves?
- Less need to replace
What are the disadvantages of mechanical valves?
- Lifelong need to take anticoagulant medication
What is the purpose of an artificial heart?
An artificial heart can keep patients alive while waiting for a heart transplant or allow the heart to rest as an aid to recovery.
What are the advantages of artificial hearts?
- Shorter waiting times
- Less chance of the patient’s immune system rejecting it
What are the disadvantages of artificial hearts?
- Do not work as well as real hearts
- Increased risk of blood clots, leading to increased risk of stroke
What is health defined as?
Health is the state of physical and mental well-being.
What are communicable diseases caused by?
Communicable diseases are caused by microorganisms called pathogens.
What are examples of communicable diseases?
- Chickenpox (varicella-zoster virus)
- Covid-19 (SARS-CoV-2 virus)
What are non-communicable diseases?
Non-communicable diseases are not caused by pathogens and have longer-lasting effects on health.
What are examples of non-communicable diseases?
- Asthma
- Coronary heart disease (CHD)
- Most cancers
What are risk factors?
Risk factors are linked to an increased rate of a disease but do not guarantee that an individual will suffer from the disease.
What are some aspects of risk factors?
- Lifestyle choices
- Substances in the body or environment
What is a causal mechanism?
A causal mechanism is a proven link between a risk factor and a disease.
How can sampling be useful in health research?
Sampling allows researchers to infer information about a population without investigating every individual.
What is the effect of lifestyle factors on non-communicable diseases?
Poor lifestyle factors increase the likelihood of individuals suffering from non-communicable diseases.
What is cancer caused by?
Cancer is caused by changes in the DNA of cells leading to uncontrolled growth and division.
What is a benign tumor?
A benign tumor is a growth of abnormal cells contained in one area, which does not invade other parts.
What causes cancer?
Changes in the DNA of cells that lead to uncontrolled growth and division
This can result in the formation of a tumour.
What usually leads to the formation of tumours?
Loss of control of the cell cycle
Tumours can be either benign or malignant.
What characterizes benign tumours?
Growths of abnormal cells contained in one area, usually within a membrane
Benign tumours do not invade other parts of the body.
What defines malignant tumours?
Cancers that invade neighbouring tissues and spread to different parts of the body
They can form secondary tumours via the blood and lymphatic system.
Why are malignant tumours dangerous?
They disrupt the functioning of the organ they originate in and the organs they spread to
This is how they can lead to death.
What factors are associated with an increased risk of developing cancer?
Increasing age and many lifestyle factors
Anyone at any age can develop cancer.
What types of therapies are being developed to improve cancer survival rates?
Targeted therapies and immunotherapy
These help improve survival rates for many different types of cancer.
What are lifestyle risk factors?
Factors identified by scientists that increase the risk of various types of cancer
These factors can vary depending on the cancer type.
What are genetic risk factors for cancer?
Inherited faulty genes that increase susceptibility to developing cancer
Examples include faulty mismatch repair (MMR) genes and BRCA genes.
What is the role of faulty mismatch repair (MMR) genes?
They are responsible for proofing DNA and their faults increase the likelihood of bowel and reproductive system cancers
Individuals with these faults are at higher risk.
How do faulty BRCA genes affect cancer risk?
Individuals with faulty BRCA genes are more likely to develop breast and ovarian cancer
This is in contrast to individuals with functioning BRCA genes.
