B2 - Organisation Flashcards
What is the process called by which cells become specialised for a particular job?
Differentiation
Differentiation occurs during the development of multicellular organisms.
What is a tissue?
A group of similar cells that work together to carry out a particular function
A tissue can include more than one type of cell.
What type of tissue makes and secretes chemicals like enzymes and hormones?
Glandular tissue
Glandular tissue plays a crucial role in the secretion of important substances.
What is an organ?
A group of different tissues that work together to perform a certain function
Organs are essential components of organ systems.
What type of tissue in the stomach moves the stomach wall to churn up food?
Muscular tissue
This action aids in the digestive process.
What tissue in the stomach makes digestive juices?
Glandular tissue
Digestive juices are critical for breaking down food.
What is an organ system?
A group of organs working together to perform a particular function
Organ systems are vital for maintaining life processes.
Name the organs that make up the digestive system.
- Glands (e.g., pancreas and salivary glands)
- Stomach
- Small intestine
- Liver
- Large intestine
These organs collaborate to break down and absorb food.
The stomach, small intestine, and liver are part of which organ system?
Digestive system
This system is responsible for food breakdown and nutrient absorption.
True or False: Tissues are made up of different types of cells.
False
A tissue is primarily a group of similar cells.
Fill in the blank: An organ is made up of _______.
[different tissues]
Organs consist of various types of tissues working together.
What role do enzymes play in chemical reactions?
Enzymes are biological catalysts that speed up chemical reactions in living organisms
What is a catalyst?
A substance that increases the speed of a reaction without being changed or used up in the reaction
What are enzymes made of?
Enzymes are large proteins made up of chains of amino acids
What is the active site of an enzyme?
The part of the enzyme that has a unique shape and fits onto the substrate involved in a reaction
True or False: Enzymes can catalyse multiple different reactions.
False
What happens to the enzyme’s active site when the substrate binds?
The active site changes shape slightly for a tighter fit, known as the ‘induced fit’ model
What is the optimum temperature for an enzyme?
The temperature at which the enzyme is most active
What occurs to an enzyme if the temperature becomes too high?
The enzyme may denature, changing the shape of its active site and preventing substrate binding
What is meant by denaturation of an enzyme?
A process where the enzyme’s structure is altered, affecting its function and active site
What is the effect of pH on enzyme activity?
pH changes can interfere with the bonds holding the enzyme together, altering its shape and activity
What is the optimum pH for most enzymes?
Often neutral pH 7, but can vary; for example, pepsin works best at pH 2
Fill in the blank: Enzymes reduce the need for _______ to speed up useful chemical reactions.
[high temperatures]
What is the ‘lock and key’ model of enzyme action?
A simplified model showing how the substrate fits into the enzyme’s active site
What is an example of an enzyme that works best in acidic conditions?
Pepsin
How do living organisms control their chemical reactions?
By producing enzymes that catalyse specific reactions
What happens to the rate of enzyme-catalysed reactions as temperature increases?
The rate increases up to a point, after which it decreases due to denaturation
What are the enzymes used in digestion produced by?
Cells
These enzymes are released into the gut to mix with food.
What do digestive enzymes break down?
Big molecules like starch, proteins, and fats
These big molecules are too large to pass through the walls of the digestive system.
What smaller molecules are produced by digestive enzymes?
Sugars (e.g., glucose and maltose), amino acids, glycerol, and fatty acids
These smaller, soluble molecules can pass easily through the walls of the digestive system.
What is the function of carbohydrases?
Convert carbohydrates into simple sugars
Amylase is an example of a carbohydrase.
Where is amylase produced?
1) Salivary glands
2) Pancreas
3) Small intestine
What do proteases convert proteins into?
Amino acids
Proteases are enzymes that facilitate this conversion.
Where are proteases made?
1) Stomach (pepsin)
2) Pancreas
3) Small intestine
What do lipases convert lipids into?
Glycerol and fatty acids
Lipids refer to fats and oils.
Where are lipases produced?
1) Pancreas
2) Small intestine
What is the role of bile in digestion?
Neutralises stomach acid and emulsifies fats
Bile is produced in the liver and stored in the gall bladder.
How does bile affect the pH in the small intestine?
It neutralises the acid and makes conditions alkaline
This is essential for enzymes in the small intestine to work properly.
What happens to fats when bile emulsifies them?
Breaks fat into tiny droplets
This increases the surface area for the enzyme lipase to work on, enhancing digestion speed.
Fill in the blank: __________ are too big to pass through the walls of the digestive system.
Big molecules
True or False: Amylase is produced only in the pancreas.
False
Amylase is also produced in the salivary glands and small intestine.
What is the primary use of glucose produced from digestion?
Used in respiration
Some glucose can also be used to make new carbohydrates, proteins, and lipids.
What is the purpose of the food tests?
To identify the type of food molecule a sample contains
What is the first step in preparing a food sample for testing?
Break up the piece of food using a pestle and mortar
What is the purpose of filtering the food sample solution?
To get rid of the solid bits of food
What type of sugars can be tested using the Benedict’s test?
Reducing sugars
What color change indicates the presence of reducing sugars in the Benedict’s test?
From blue to green, yellow, or brick-red
What is the temperature set for the water bath in the Benedict’s test?
75 °C
What solution is used to test for starch in food samples?
Iodine solution
What color change indicates the presence of starch when using iodine solution?
From browny-orange to black or blue-black
What test is used to determine the presence of proteins in food?
Biuret test
What color change indicates the presence of protein in the Biuret test?
From blue to purple
What test is used to check for lipids in food samples?
Sudan III test
What happens to the mixture if lipids are present in the Sudan III test?
It separates into two layers with a bright red top layer
What types of foods are rich in proteins?
- Meat
- Cheese
Fill in the blank: The _______ test is used to test for the presence of starch.
Iodine
True or False: The Biuret solution will turn purple if protein is present.
True
Fill in the blank: If no lipids are present in the Sudan III test, no separate _______ layer will form at the top of the liquid.
red
Which foods are typically tested for starch?
- Pasta
- Rice
- Potatoes
What is the primary function of enzymes in digestion?
To catalyse the breakdown of food molecules
Different enzymes are responsible for breaking down different types of food.
What enzyme is produced by the salivary glands?
Amylase
Amylase is found in saliva and begins the process of starch digestion.
Where is bile produced?
Liver
Bile helps to neutralise stomach acid and emulsifies fats.
What are the two main functions of hydrochloric acid in the stomach?
- To kill bacteria
- To provide the right pH for the protease enzyme to work (pH 2 — acidic)
The acidic environment is crucial for the activation of pepsin, a protease enzyme.
What enzyme is produced in the stomach?
Pepsin
Pepsin is a protease that breaks down proteins into peptides.
What is the role of the gall bladder in digestion?
Stores bile before it’s released into the small intestine
Bile is essential for fat digestion.
What enzymes does the pancreas produce?
- Protease
- Amylase
- Lipase
These enzymes are released into the small intestine to aid in digestion.
What happens in the large intestine?
Excess water is absorbed from the food
This process helps to concentrate waste material.
What is the function of the small intestine?
- Produces protease, amylase, and lipase enzymes
- Absorbs digested food into the blood
The small intestine is the primary site for digestion and nutrient absorption.
What is stored in the rectum?
Faeces
Faeces are composed mainly of indigestible food.
Fill in the blank: The _______ is where bile is stored.
Gall bladder
Bile is released into the small intestine from the gall bladder.
True or False: The stomach has muscular walls that pummel the food.
True
This action helps to mix food with gastric juices.
What is the thorax?
The top part of your body that is separated from the lower part by the diaphragm.
What are the lungs compared to in terms of structure?
Big pink sponges.
What protects the lungs?
The ribcage.
What surrounds the lungs?
Pleural membranes.
What is the trachea?
The windpipe through which air enters the lungs.
What are bronchi?
Two tubes that split from the trachea, leading to each lung.
What are bronchioles?
Progressively smaller tubes that split from the bronchi.
What are alveoli?
Small bags at the end of bronchioles where gas exchange occurs.
What happens in the alveoli?
Gas exchange occurs between oxygen and carbon dioxide.
What is the primary function of alveoli?
To facilitate the exchange of gases between air and blood.
How does oxygen move during gas exchange?
Oxygen diffuses from the alveolus (high concentration) into the blood (low concentration).
How does carbon dioxide move during gas exchange?
Carbon dioxide diffuses from the blood (high concentration) into the alveolus (low concentration).
What is the role of red blood cells in gas exchange?
Red blood cells release oxygen to body cells and absorb carbon dioxide.
Fill in the blank: The diaphragm separates the thorax from the _______.
[lower part of the body]
How do you calculate breathing rate in breaths per minute?
Breathing rate = number of breaths ÷ number of minutes.
If Bea takes 91 breaths in 7 minutes, what is her average breathing rate?
13 breaths per minute.
True or False: Alveoli are surrounded by blood capillaries.
True.
What is the function of the pleural membranes?
To protect and surround the lungs.
What are the main components of the circulatory system?
The heart, blood vessels, and blood.
What type of circulatory system do humans have?
A double circulatory system.
What does the right ventricle do in the circulatory system?
Pumps deoxygenated blood to the lungs.
What happens to blood in the lungs?
It takes in oxygen.
What does the left ventricle do?
Pumps oxygenated blood around the body.
What is the function of the heart?
Keeps the blood flowing around the body.
What are the four chambers of the heart?
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
What role do valves play in the heart?
Ensure blood flows in the right direction and prevent backflow.
What is the sequence of blood flow through the heart?
1) Blood flows into the atria
2) Atria contract, pushing blood into ventricles
3) Ventricles contract, forcing blood into arteries
4) Blood flows to organs through arteries and returns through veins
How does the heart receive its own oxygenated blood?
Through coronary arteries that branch off the aorta.
What is the pacemaker of the heart?
A group of cells in the right atrium wall that control the resting heart rate.
What do the pacemaker cells produce?
A small electric impulse.
What is the purpose of an artificial pacemaker?
To control heartbeat if natural pacemaker cells do not work properly.
Fill in the blank: The heart has ________ chambers.
four
True or False: The atria fill with blood again after the ventricles contract.
True
What is the role of the vena cava and pulmonary vein?
They bring blood into the atria.
What is the function of the aorta?
Carries oxygenated blood away from the heart to the body.
What are the three different types of blood vessels?
- Arteries
- Capillaries
- Veins
Each type has a specific function in the circulatory system.
What is the primary function of arteries?
To carry blood away from the heart
Arteries transport oxygenated blood (except for pulmonary arteries) under high pressure.
What is the structure of artery walls?
Strong, elastic, thick walls with muscle and elastic fibres
This structure allows them to withstand and maintain high pressure from the heart.
What are capillaries involved in?
The exchange of materials at the tissues
Capillaries connect arteries and veins and facilitate the transfer of oxygen, nutrients, and waste.
What is unique about capillary walls?
They are only one cell thick
This thinness increases the rate of diffusion by reducing the distance for exchange.
What is the primary function of veins?
To carry blood back to the heart
Veins transport deoxygenated blood (except for pulmonary veins) under lower pressure.
How do the walls of veins compare to those of arteries?
Thinner walls and a larger lumen
This structure accommodates lower pressure and facilitates blood flow.
What do veins contain to aid blood flow?
Valves
Valves prevent backflow and ensure blood flows in the correct direction.
Fill in the blank: The _______ is the space inside the blood vessel.
lumen
The lumen is crucial for the amount of blood that can flow through the vessel.
How can you calculate the rate of blood flow?
Rate of blood flow = volume of blood ÷ number of minutes
This formula helps determine how quickly blood is moving through a vessel.
True or False: Capillaries are too small to see.
True
Their tiny size is essential for effective exchange with tissues.
What is the primary function of red blood cells?
To carry oxygen from the lungs to all the cells in the body.
Describe the shape of red blood cells and its significance.
Biconcave disc shape; provides a large surface area for absorbing oxygen.
Why do red blood cells not have a nucleus?
To allow more room to carry oxygen.
What pigment do red blood cells contain?
Haemoglobin.
What happens to haemoglobin in the lungs?
It binds to oxygen to become oxyhemoglobin.
What occurs to oxyhemoglobin in body tissues?
It splits up into haemoglobin and oxygen, releasing oxygen to the cells.
How do high altitudes affect red blood cell production?
People produce more red blood cells to compensate for lower oxygen levels.
What is the role of white blood cells?
To defend against infection.
What process do some white blood cells use to engulf microorganisms?
Phagocytosis.
What do other white blood cells produce to combat microorganisms?
Antibodies and antitoxins.
Do white blood cells have a nucleus?
Yes, they do have a nucleus.
What are platelets and what is their function?
Small fragments of cells that help blood to clot.
Do platelets have a nucleus?
No, they do not have a nucleus.
What can a lack of platelets lead to?
Excessive bleeding and bruising.
What is plasma and what does it carry?
A pale straw-coloured liquid that carries red and white blood cells, platelets, nutrients, carbon dioxide, urea, hormones, proteins, antibodies, and antitoxins.
What nutrients does plasma transport?
Glucose and amino acids.
Where do nutrients in plasma come from?
They are soluble products of digestion absorbed from the gut.
What does plasma carry from the organs to the lungs?
Carbon dioxide.
What does plasma carry from the liver to the kidneys?
Urea.
What role do antibodies and antitoxins play?
They are produced by white blood cells to fight microorganisms and neutralize toxins.
What is coronary heart disease?
When the coronary arteries that supply blood to the heart muscle get blocked by fatty material buildup
This blockage restricts blood flow and can lead to a heart attack.
What happens to arteries in coronary heart disease?
They become narrow, restricting blood flow and causing a lack of oxygen to the heart muscle.
What is the role of stents in treating coronary heart disease?
Stents lower the risk of a heart attack by keeping arteries open and allowing blood to flow more freely.
How do stents function within an artery?
They push the artery wall out and create more space in the center for blood to pass through.
What are some risks associated with stent surgery?
Risks include complications during the operation, infection, and thrombosis (blood clots near the stent).
What is cholesterol?
An essential lipid produced by the body that is necessary for proper functioning.
What is considered ‘bad’ cholesterol?
‘Bad’ cholesterol is known as LDL cholesterol, which can cause health problems when in excess.
How do high levels of ‘bad’ cholesterol affect arteries?
They can cause fatty deposits to form inside arteries, leading to coronary heart disease.
What are statins?
Drugs that reduce the amount of ‘bad’ cholesterol in the bloodstream.
What are the advantages of taking statins?
They reduce the risk of strokes, coronary heart disease, and heart attacks, and can increase ‘good’ HDL cholesterol.
What is ‘good’ cholesterol?
‘Good’ cholesterol is known as HDL cholesterol, which helps remove ‘bad’ cholesterol from the blood.
What are some disadvantages of statins?
They must be taken regularly, can cause side effects (e.g., headaches), and their effects take time to manifest.
Fill in the blank: Statins can sometimes cause negative side effects, such as _______.
headaches
True or False: Statins provide immediate effects on cholesterol levels.
False
What serious side effects can statins potentially cause?
Kidney failure, liver damage, and memory loss.
What is the primary purpose of an artificial heart?
To pump blood for a person whose own heart has failed
Artificial hearts are used temporarily while waiting for a donor heart or to help the heart recover.
What is a significant advantage of artificial hearts?
Less likely to be rejected by the body’s immune system
The body does not recognize artificial hearts as foreign like it does with donor organs.
What are the potential complications of surgery to fit an artificial heart?
Bleeding and infection
Surgery for artificial hearts comes with risks similar to those of transplant surgery.
True or False: Artificial hearts function as well as natural hearts.
False
Artificial hearts do not work as efficiently as healthy natural ones.
What types of valves can replace faulty heart valves?
Biological and mechanical valves
Biological valves can be taken from humans or animals, while mechanical valves are man-made.
What can cause damage to heart valves?
Heart attacks, infection, or old age
Damaged valves may not open properly or may leak, affecting blood circulation.
What is artificial blood used for?
To replace lost blood volume in emergencies
Artificial blood can keep a person alive even after significant blood loss.
Fill in the blank: Artificial blood is a blood substitute, e.g., a _______.
salt solution (saline)
Saline can replace lost volume of blood and keep patients stable until they can produce new blood cells.
What happens if a patient loses a significant amount of blood?
Their heart can pump remaining red blood cells, as long as blood volume is topped up
This allows oxygen to reach organs temporarily.
What is a goal of scientists regarding artificial blood products?
To replace the function of lost red blood cells
Ideally, this would eliminate the need for blood transfusions.
What are the risks associated with artificial heart valves?
Problems with blood clots
Fitting artificial valves still carries risks, similar to those of an artificial heart.
What are risk factors?
Things linked to an increase in the likelihood of developing a disease during a person’s lifetime.
Do risk factors guarantee that someone will get a disease?
No, they do not guarantee disease development.
What can risk factors be related to?
Aspects of lifestyle, environmental substances, or substances in the body.
What is an example of a substance that can build up in the airways and cause diseases?
Asbestos fibres.
How do lifestyle factors impact disease incidence?
They can have different impacts locally, nationally, and globally.
In developed countries, why are non-communicable diseases more common?
Higher income allows for the purchase of high-fat food.
What demographic is more likely to smoke and have a poor diet?
People from deprived areas.
Which diseases are more prevalent in deprived areas?
Cardiovascular disease, obesity, and Type 2 diabetes.
What is a direct cause of cardiovascular disease?
Smoking.
How can obesity directly cause Type 2 diabetes?
By making the body less sensitive or resistant to insulin.
What disease can excessive alcohol consumption cause?
Liver disease.
What are carcinogens?
Substances that can directly cause cancer.
Give an example of a carcinogen.
Ionising radiation (e.g., from X-rays).
What is the relationship between lack of exercise, high fat diet, and cardiovascular disease?
They are linked to an increased chance but cannot directly cause the disease.
What can actually cause cardiovascular disease related to lifestyle factors?
High blood pressure and high ‘bad’ cholesterol levels.
What is the human cost of non-communicable diseases?
Tens of millions of deaths and lower quality of life.
What is a financial cost associated with non-communicable diseases?
High costs for healthcare services and loss of family income.
Fill in the blank: The cost to the NHS of researching and treating non-communicable diseases is _______.
huge.
How can a family member’s illness affect their household?
They may have to adapt their home, and income may be reduced.
What can a reduction in the working population affect?
A country’s economy.
What is cancer caused by?
Uncontrolled cell growth and division
Cancer results from cells dividing uncontrollably, leading to the formation of tumors.
What is a benign tumor?
A tumor that does not invade surrounding tissues and is not cancerous
Benign tumors remain localized and do not pose significant health risks.
What characterizes a malignant tumor?
It invades healthy tissues and can spread to other parts of the body
Malignant tumors are dangerous and can lead to secondary tumors.
True or False: Having risk factors guarantees that a person will develop cancer.
False
Risk factors increase the likelihood but do not ensure cancer development.
What has contributed to increased cancer survival rates?
Medical advances, earlier diagnosis, and increased screening
Improved treatment options and early detection are key to better outcomes.
Name a lifestyle risk factor associated with cancer.
- Smoking
- Obesity
- UV exposure
- Viral infection
These factors can increase the risk of various types of cancer.
How is smoking linked to cancer?
It is strongly linked to lung cancer and other cancers like mouth, bowel, stomach, and cervical cancer
Smoking is the leading preventable cause of cancer.
What type of cancer is obesity associated with?
Bowel, liver, and kidney cancer
Obesity is the second biggest preventable cause of cancer after smoking.
What increases the risk of developing skin cancer?
UV exposure from the Sun and sunbeds
People in sunny climates or those who spend a lot of time outdoors are at higher risk.
Which viruses are associated with an increased risk of liver cancer?
Hepatitis B and hepatitis C
These infections can spread through unprotected sex or sharing needles.
What genetic factor can increase susceptibility to cancer?
Inherited faulty genes
Genetic mutations, such as in the BRCA genes, are linked to breast and ovarian cancer.
Fill in the blank: Obesity is the _______ biggest preventable cause of cancer after smoking.
second
Obesity is a significant lifestyle risk factor for multiple cancers.
What are the main components of plant cell organisation?
Tissues and organs
Plant organs work together to form organ systems that perform necessary tasks for survival and growth.
What is epidermal tissue?
Covers the whole plant
Epidermal tissue acts as a protective layer for the plant.
Where does most photosynthesis occur in a leaf?
Palisade mesophyll tissue
This tissue contains many chloroplasts for optimal light absorption.
What is the function of spongy mesophyll tissue?
Contains air spaces for gas diffusion
This facilitates the exchange of gases within the leaf.
What do xylem and phloem transport in plants?
Water, minerals, and food
They transport these substances through the roots, stems, and leaves.
What is meristem tissue responsible for?
Growth and differentiation
Found at the growing tips of shoots and roots.
What is the role of the waxy cuticle on epidermal tissues?
Reduces water loss by evaporation
This adaptation helps the plant retain moisture.
Why is the upper epidermis of a leaf transparent?
To allow light to pass through to the palisade layer
This is crucial for photosynthesis.
What do guard cells control in the leaf?
Opening and closing of stomata
This regulation responds to environmental conditions.
What is the function of stomata in leaves?
Allow CO2 to diffuse into the leaf
Stomata are essential for gas exchange.
Fill in the blank: The palisade layer has lots of _______ where photosynthesis takes place.
chloroplasts
What does the term ‘mesophyll’ mean?
Middle of a leaf
This term refers to the tissue layers within the leaf.
What do the xylem and phloem form in the leaf?
A network of vascular bundles
This network supports the leaf structure and facilitates transport.
True or False: The air spaces in spongy mesophyll tissue decrease the rate of gas diffusion.
False
The air spaces actually increase the rate of gas diffusion.
What are phloem tubes made of?
Columns of elongated living cells with small pores in the end walls
Phloem tubes allow cell sap to flow through, transporting food substances.
What do phloem tubes transport?
Food substances (mainly dissolved sugars)
These substances are made in the leaves and transported to the rest of the plant.
In which directions do phloem tubes transport substances?
Both directions
This allows for immediate use or storage of food substances within the plant.
What is the process called that involves the transport of food in phloem tubes?
Translocation
This process involves the movement of cell sap, which is a liquid made up of the substances being transported and water.
What are xylem tubes made of?
Dead cells joined end to end with no end walls
Xylem tubes have a hole down the middle and are strengthened with lignin.
What do xylem tubes carry?
Water and mineral ions
They transport these substances from the roots to the stem and leaves.
What is the transpiration stream?
The movement of water from the roots, through the xylem, and out of the leaves
This process is essential for maintaining water levels within the plant.
What is transpiration?
The loss of water from the plant
It occurs mainly through evaporation from the leaves.
Where does most transpiration occur?
At the leaves
This is due to the large surface area and stomata present on leaves.
What causes transpiration?
Evaporation and diffusion of water from a plant’s surface
This process creates a slight water shortage in the leaf, prompting water to be drawn up from the roots.
What is the role of stomata in transpiration?
They allow gases to be exchanged easily
Stomata facilitate the diffusion of water from the inside of the plant to the outside air.
Fill in the blank: Transpiration is just a side-effect of the way leaves are adapted for _______.
Photosynthesis
Leaves must have stomata for gas exchange, which also leads to water loss.
True or False: The water inside the plant is at a higher concentration than in the air outside.
True
This difference in concentration causes water to escape from the leaves through diffusion.
What are the four main factors that affect the transpiration rate?
- Light Intensity
- Temperature
- Air Flow
- Humidity
How does light intensity affect transpiration rate?
The brighter the light, the greater the transpiration rate. Stomata close in darkness.
What is the relationship between temperature and transpiration?
The warmer it is, the faster transpiration happens due to increased energy for evaporation.
How does air flow influence transpiration?
Better air flow increases transpiration by sweeping away water vapor, maintaining a low concentration outside the leaf.
Explain the effect of humidity on transpiration.
The drier the air around a leaf, the faster transpiration happens due to a greater concentration difference.
What is a potometer used for?
To estimate the rate of transpiration by measuring the uptake of water by a plant.
What happens to guard cells when the plant has lots of water?
Guard cells fill with water, become turgid, and open the stomata for gas exchange.
What occurs to guard cells when the plant is short of water?
Guard cells lose water, become flaccid, and close the stomata to reduce water loss.
What is the structural adaptation of guard cells for stomata function?
They have a kidney shape, thin outer walls, and thickened inner walls for effective opening and closing.
Where are stomata usually found on leaves?
More stomata are found on the undersides of leaves, which are shaded and cooler.
True or False: Stomata open at night to allow for gas exchange.
False. Stomata close at night to save water.
Fill in the blank: Transpiration is the process of _______ from plant leaves.
[water vapor loss]
