B2 Flashcards
What are the basic building blocks that make up all living organisms?
Cells
Cells are the fundamental units of life, responsible for carrying out various functions.
What is a group of similar cells that work together to carry out a function called?
Tissue
An example of a tissue is epithelial tissue, which covers body surfaces.
What type of tissue is made of epithelial cells and covers some parts of the human body?
Epithelial tissue
It lines the inside of the gut and other areas.
What is an organ?
A group of tissues that work together to perform a certain function
For example, the stomach is an organ made of different tissues.
Give an example of an organ system.
Digestive system
The digestive system is responsible for breaking down and absorbing food.
What does the digestive system do?
Breaks down and absorbs food
It consists of various organs such as the stomach, liver, and intestines.
Which organs are part of the digestive system?
- Salivary glands
- Liver
- Stomach
- Pancreas
- Small intestine
- Large intestine
Each organ has a specific role in digestion.
Fill in the blank: An organ system is a group of organs working together to perform a _______.
Function
Organ systems coordinate to achieve complex biological tasks.
True or False: Tissues are made up of organs.
False
Tissues are made up of cells, while organs are made of tissues.
What is the relationship between cells, tissues, organs, and organ systems in an organism?
Cells make up tissues, tissues make up organs, and organs make up organ systems
This hierarchical organization is essential for the complexity of multicellular organisms.
What organ produces bile?
Liver
Bile is important for digestion and fat absorption.
What does the large intestine do?
Absorbs water from undigested food, leaving faeces
It plays a crucial role in water balance and waste elimination.
What type of tissue lines the inside and outside of the stomach?
Epithelial tissue
This tissue is vital for protecting and facilitating absorption.
What are enzymes?
Large proteins that control chemical reactions in living things
Enzymes are crucial for metabolism and are involved in various biochemical reactions.
What is a catalyst?
A substance that increases the speed of a reaction without being changed or used up in the reaction
Enzymes function as biological catalysts.
What is the role of enzymes in metabolism?
They speed up reactions inside living things
Metabolism encompasses all chemical reactions in a living organism.
What is an active site?
The specific region on an enzyme where the substrate binds
Each enzyme has a unique shape for its active site, allowing it to catalyze specific reactions.
What is a substrate?
The substance that an enzyme acts on
The substrate must fit into the enzyme’s active site for the reaction to occur.
How does temperature affect enzyme activity?
Higher temperatures increase reaction rates until a point where the enzyme denatures
Denaturation involves the breaking of bonds that maintain the enzyme’s shape.
What happens to an enzyme when it denatures?
The shape of the enzyme’s active site changes, preventing substrate binding
Factors like extreme temperature or pH can lead to denaturation.
What is the optimum temperature for enzymes?
The temperature at which an enzyme works best
This varies among different enzymes but is critical for their functional efficiency.
What effect does pH have on enzymes?
Extreme pH levels can denature enzymes by altering their shape
Each enzyme has an optimum pH at which it functions best.
Fill in the blank: An enzyme is denatured if the pH is too _______.
[high or low]
True or False: Enzymes can catalyze multiple reactions.
False
Enzymes are specific and usually catalyze only one type of reaction.
What is the relationship between enzyme shape and function?
The specific shape of the enzyme’s active site determines its function
Enzymes are ‘picky’ due to their unique shapes, which only allow specific substrates.
What does the enzyme amylase catalyse?
The breakdown of starch to sugar
What color change indicates the presence of starch when using iodine solution?
From browny-orange to blue-black
At what temperature should the water bath be set for the enzyme activity experiment?
35 °C
What solution should be added to the boiling tube along with amylase?
A buffer solution with a pH of 5
How often should samples be taken from the boiling tube during the experiment?
Every 30 seconds
What indicates that all the starch in the sample has been broken down?
The iodine solution in the well does not change color
What must be controlled to ensure a fair test in the enzyme activity experiment?
Concentration and volume of the amylase solution
How is the rate of reaction calculated in the enzyme activity experiment?
Rate = 1000 ÷ time
If it took 90 seconds for amylase to break down starch, what is the rate of reaction?
11.11 s⁻¹
What are the three types of digestive enzymes mentioned?
- Carbohydrases
- Proteases
- Lipases
What is the role of bile in digestion?
Bile is a neutraliser
Fill in the blank: Glucose is a _______.
product of starch breakdown
True or False: Repeating the experiment at each pH is not necessary.
False
What is the significance of controlling variables in the enzyme experiment?
To make it a fair test
What is the primary function of digestive enzymes?
To break down large food molecules into smaller, soluble molecules
What type of carbohydrate is starch?
A carbohydrate
What are the enzymes used in digestion produced by?
Cells
Enzymes are released into the gut to mix with food.
What do digestive enzymes break down?
Big molecules
Starch, proteins, and fats are examples of big molecules.
Why must big molecules be broken down during digestion?
They are too big to pass through the walls of the digestive system.
What are the smaller molecules produced by digestive enzymes?
Smaller, soluble molecules
These can be easily absorbed into the bloodstream.
What type of enzyme is amylase?
Carbohydrase
Amylase is an example of a carbohydrase.
Where is amylase produced?
Salivary glands, pancreas, and small intestine.
Where does amylase work in the body?
Mouth and small intestine.
What is starch classified as?
A carbohydrate.
What type of enzymes are proteases?
Proteases
They break down proteins.
Where are proteases produced?
Stomach, pancreas, and small intestine.
Where do proteases work?
Stomach and small intestine.
What do lipases break down?
Lipids
Lipids are fats and oils.
Where are lipases produced?
Pancreas and small intestine.
Where do lipases work in the body?
Small intestine.
What are the products of digestion used to make?
New carbohydrates, proteins, and lipids.
What is glucose produced by digestion?
A sugar.
What is the purpose of bile in digestion?
Neutralises stomach acid and emulsifies fats.
Where is bile produced?
Liver.
Where is bile stored before being released?
Gall bladder.
What type of solution is bile?
Alkaline.
What does bile neutralise?
Hydrochloric acid.
Why does bile make conditions alkaline?
Enzymes in the small intestine work best in alkaline conditions.
What does emulsify mean in the context of bile?
Breaks fats down into tiny droplets.
How does emulsifying fats help digestion?
Increases surface area for lipase to work on.
What is the first step in preparing a food sample for testing?
Get a piece of food and break it up using a pestle and mortar.
What is the purpose of adding distilled water to the ground food in the testing process?
To dissolve some of the food.
What is the purpose of filtering the mixture after adding distilled water?
To get rid of the solid bits of food.
What type of sugar does the Benedict’s test detect?
Reducing sugar.
What temperature should the water bath be set to for the Benedict’s test?
75 °C.
How many drops of Benedict’s solution are needed for the test?
About 10 drops.
What color change indicates the presence of starch when using iodine solution?
Browny-orange to black or blue-black.
What is the first step in the Biuret test for proteins?
Prepare a sample of your food and transfer 2 cm³ to a test tube.
What color change indicates the presence of protein in the Biuret test?
From blue to purple.
How many drops of Sudan III stain solution are added in the lipid test?
3 drops.
What indicates the presence of lipids in the Sudan III test?
The mixture will separate into two layers with a bright red top layer.
What should be done before starting food tests?
Conduct a risk assessment.
Fill in the blank: The solution used to test for starch is _______.
iodine solution.
True or False: Glucose is not a reducing sugar.
False.
What is the volume of food sample needed for the Benedict’s test?
5 cm³.
After adding the Biuret solution, how should the test tube be mixed?
By gently shaking it.
What happens to the color of the solution in the Biuret test if protein is present?
It changes from blue to purple.
What does the top layer look like if lipids are present in the Sudan III test?
Bright red.
What is the primary function of the lungs?
To supply oxygen for respiration and remove carbon dioxide
This process occurs when you breathe air in and out.
What is the pathway of air as it enters the lungs?
Trachea → Bronchi → Bronchioles → Alveoli
The trachea is also known as the windpipe.
What surrounds the alveoli in the lungs?
Blood capillaries
This structure facilitates gas exchange.
What happens to oxygen in the alveoli?
Oxygen diffuses from the alveolus into the blood
This occurs due to a higher concentration of oxygen in the alveolus.
What happens to carbon dioxide in the alveoli?
Carbon dioxide diffuses from the blood into the alveolus
This occurs because of a higher concentration of carbon dioxide in the blood.
How can you calculate the breathing rate?
Breathing rate = number of breaths ÷ number of minutes
This calculation gives the average breaths per minute.
If Bev takes 91 breaths in 7 minutes, what is her average breathing rate?
13 breaths per minute
Calculation: 91 ÷ 7 = 13.
What is the term for the small air sacs in the lungs?
Alveoli
One alveolus corresponds to many alveoli.
True or False: There is one bronchus and two bronchi.
True
The term ‘bronchi’ refers to the plural form.
Fill in the blank: The air you breathe in goes through the _______.
trachea
What is the significance of alveoli in gas exchange?
Alveoli are well adapted for carrying out gas exchange
Their structure allows for efficient diffusion of gases.
What is the main function of the heart in the circulatory system?
The heart pumps blood around the body
This includes both deoxygenated and oxygenated blood through different circuits.
What are the components of the circulatory system?
The circulatory system is made up of the heart, blood vessels, and blood
Blood vessels include arteries, veins, and capillaries.
What is a double circulatory system?
A double circulatory system consists of two circuits joined together
The first circuit involves the heart pumping deoxygenated blood to the lungs, and the second circuit involves pumping oxygenated blood to the rest of the body.
Where does deoxygenated blood go after it leaves the heart?
Deoxygenated blood is pumped to the lungs
This occurs via the pulmonary artery.
What happens to oxygenated blood after it returns to the heart?
Oxygenated blood is pumped around all the organs of the body
This occurs via the aorta.
How many chambers does the heart have?
The heart has four chambers
These are the right atrium, left atrium, right ventricle, and left ventricle.
What is the role of the muscle tissue in the heart?
The muscle tissue is used to pump blood around the body
This muscle is known as cardiac muscle.
What are the two types of blood vessels?
Arteries and veins
Arteries carry blood away from the heart, while veins carry blood back to the heart.
What is the primary function of arteries?
Arteries carry oxygenated blood away from the heart
The exception is the pulmonary artery, which carries deoxygenated blood to the lungs.
What is the main characteristic of capillaries?
Capillaries have thin walls that are only one cell thick
This allows for efficient gas exchange.
What do veins do?
Veins take deoxygenated blood back to the heart
They have thinner walls compared to arteries.
What controls the resting heart rate?
A group of cells in the right atrium wall acts as a pacemaker
These cells signal the heart when to pump blood.
What can happen if a pacemaker does not work properly?
It can cause an irregular heartbeat
An artificial pacemaker can be used to regulate heartbeats.
Fill in the blank: The valves in the heart prevent blood from flowing _______.
backwards
True or False: The heart receives its own supply of oxygenated blood from the pulmonary vein.
False
The heart receives oxygenated blood from the coronary arteries.
Fill in the blank: Blood from the right ventricle goes through the _______ to the lungs.
pulmonary artery
What is the function of the coronary arteries?
They supply oxygenated blood to the heart
Coronary arteries branch off the aorta and surround the heart.
What do doctors hear when they use a stethoscope?
The valves closing in the heart
This sound indicates the pumping action of the heart.
What is the primary function of arteries?
Carry blood away from the heart
Arteries transport oxygenated blood, except for the pulmonary artery.
How do arteries adapt to carry blood under high pressure?
Strong and elastic walls with thick muscle layers
This structure allows arteries to withstand and manage the pressure from the heart’s pumping action.
What is the lumen of an artery?
The hole down the middle of the artery
The lumen’s size affects blood flow; it is relatively small in arteries.
What are capillaries characterized by?
Really small size and thin walls
Capillaries are only one cell thick, facilitating quick diffusion of substances.
What is the role of capillaries in the circulatory system?
Exchange substances with cells
Capillaries supply food and oxygen and remove waste products.
What do capillary walls allow to happen?
Substances to diffuse in and out
The gaps in capillary walls enable this process, supporting cellular metabolism.
What is the function of veins?
Take blood back to the heart
Veins primarily transport deoxygenated blood, except for the pulmonary vein.
How do veins differ from arteries in terms of pressure?
Blood is at lower pressure in veins
This lower pressure means that veins have thinner walls compared to arteries.
What structural feature of veins helps facilitate blood flow?
Larger lumen than arteries
The larger lumen allows for easier blood flow despite the lower pressure.
What do veins have to ensure blood flows in the right direction?
Valves
Valves prevent backflow, maintaining unidirectional flow towards the heart.
How do you calculate the rate of blood flow?
Rate of blood flow = volume of blood ÷ number of minutes
This formula provides flow rate in ml/min.
If 1300 ml of blood passes through an artery in 4 minutes, what is the rate of blood flow?
325 ml per minute
Calculation: 1300 ÷ 4 = 325.
What is a fact about the total length of blood vessels in the human body?
About 60,000 miles of blood vessels
This extensive network supports efficient circulation throughout the body.
Fill in the blank: Capillaries are too small to _____.
see
Capillaries are microscopic and not visible without a microscope.
True or False: The walls of veins are thicker than those of arteries.
False
Veins have thinner walls due to the lower pressure of blood within them.
What type of blood do veins primarily carry?
Deoxygenated blood
The pulmonary vein is an exception, carrying oxygenated blood from the lungs.
What is the job of red blood cells?
To carry oxygen from the lungs to all the cells in the body.
What allows red blood cells to carry oxygen?
Haemoglobin.
What is a unique feature of red blood cells that aids in oxygen transport?
They don’t have a nucleus.
What is the function of white blood cells?
To defend against infection.
What do some white blood cells produce to fight infections?
Antibodies and antitoxins.
What is coronary heart disease caused by?
Fatty deposits building up in the coronary arteries.
What is the effect of fatty deposits in the coronary arteries?
It reduces blood flow and less oxygen reaches the heart.
What can result from reduced blood flow to the heart?
A heart attack.
What are stents?
Tubes that keep arteries open to allow blood to flow.
What is the role of platelets in blood?
To help blood clot at a wound.
What do platelets prevent when they help blood to clot?
They stop blood from pouring out and microorganisms from getting in.
What does plasma carry in the blood?
- Red and white blood cells and platelets
- Food molecules (like glucose and amino acids)
- Waste products (like carbon dioxide and urea)
- Hormones
- Proteins
What is cholesterol?
A substance that can lead to coronary heart disease if levels are too high.
What is the purpose of statins?
To reduce cholesterol levels in the blood.
What are some advantages of statins?
They slow down the production of cholesterol.
What are some disadvantages of statins?
- Potential side effects
- Risk of infection after procedures
True or False: Blood tests can diagnose only blood disorders.
False.
Fill in the blank: Platelets are ______ of cells.
small fragments
What are cardiovascular diseases?
Diseases of the heart or blood vessels
Includes conditions like coronary heart disease.
What is coronary heart disease?
A disease of the coronary arteries
It involves fatty deposits building up in the arteries.
What do the coronary arteries supply?
Blood to the heart muscle
Essential for heart function.
What causes the narrowing of coronary arteries?
Layers of fatty material (fatty deposits) build up
This reduces blood flow to the heart muscle.
What is a potential consequence of reduced blood flow to the heart muscle?
Heart attack
Caused by insufficient oxygen reaching the heart.
What is the purpose of stents?
To keep the coronary arteries open
Allows blood to reach the heart muscles.
How are stents placed in the body?
Through surgery
They are tubes inserted into coronary arteries.
What are some risks associated with stent surgery?
Heart attack during operation, infection after surgery, blood clot near stent
These risks can complicate recovery.
What is cholesterol?
A lipid that the body needs
Essential but can be harmful in excess.
What can too much cholesterol lead to?
Formation of fatty deposits inside arteries
This can contribute to cardiovascular diseases.
What are statins?
Drugs that reduce cholesterol in the blood
They slow the rate of fatty deposit formation.
List two advantages of statins.
- Reduce risk of strokes
- Reduce risk of coronary heart disease and heart attacks
Some studies suggest additional health benefits.
List two disadvantages of statins.
- Must be taken regularly
- Can cause side effects like headaches
Effects take time to manifest.
True or False: Stents are effective for a long time.
True
They provide a long-term solution to arterial blockage.
Fill in the blank: Statins can help prevent some other _______.
[diseases]
This is based on some studies suggesting broader benefits.
What is an artificial heart?
A machine that pumps blood around the body.
What is a heart transplant?
When a person’s heart is replaced by a donor heart from someone who has recently died.
What is heart failure?
When the heart can’t pump enough blood.
What can be done if a donor heart isn’t available?
Doctors may fit an artificial heart.
What are the two main purposes of artificial hearts?
- Keep a person alive until a donor heart is available
- Help a person recover by allowing the heart to rest and heal.
Can artificial hearts be permanent?
Yes, sometimes artificial hearts are permanent.
What are some advantages of artificial hearts?
- Made from metals or plastics
- Less likely to be attacked by the body’s immune system.
What are some disadvantages of artificial hearts?
- Surgery can lead to bleeding and infection
- Don’t work as well as healthy natural hearts
- Blood flow is not as smooth, which can cause clots and strokes.
- Patients must take drugs to thin their blood.
Define health.
The state of physical and mental well-being.
What are communicable diseases?
Diseases that can be transmitted from one person to another.
Give two examples of communicable diseases.
- Measles
- Malaria.
What are non-communicable diseases?
Diseases that cannot be transmitted between individuals.
What can damage heart valves?
- Heart attacks
- Infection
- Old age.
What happens when a heart valve becomes stiff?
It won’t open properly.
What is a leaky valve?
A valve that allows blood to flow in both directions instead of just forward.
What are biological valves?
Valves from humans or other mammals (e.g., cows or pigs).
What are mechanical valves?
Man-made valves used to replace damaged heart valves.
Is replacing a valve riskier than a heart transplant?
No, it is less risky than a heart transplant.
What is a potential problem with valve replacement?
There can still be problems with blood clots.
What lifestyle factor can affect heart health?
A poor diet.
Fill in the blank: Diseases are often responsible for _______.
[health issues].
True or False: Artificial hearts can completely replicate the function of a natural heart.
False.
What is the definition of health?
Health is the state of physical and mental wellbeing.
What are the two main types of diseases?
Communicable and non-communicable diseases.
What are communicable diseases?
Diseases that can spread from person to person or between animals and people.
What can cause communicable diseases?
Bacteria, viruses, parasites, or fungi.
Give two examples of communicable diseases.
- Measles
- Malaria
What are non-communicable diseases?
Diseases that cannot spread between people or between animals and people.
Give an example of a non-communicable disease.
Coronary heart disease.
How can diseases interact with each other?
A disease can cause other physical and mental health issues.
What role does the immune system play in health?
The immune system helps to fight off pathogens.
What is a pathogen?
A microorganism that can cause disease.
How can an immune system reaction affect health?
It may lead to allergic reactions or worsen symptoms of asthma.
What can viruses do to cells in the body?
Viruses infect cells, which can lead to some types of cancer.
How can physical health problems impact mental health?
Physical health problems may lead to mental health problems, such as depression.
What effect does a poor diet have on health?
It can affect both physical and mental health.
What is a balanced diet?
A diet that provides the body with everything it needs, in the right amounts.
How can stress affect health?
Being constantly under lots of stress can lead to poor health.
What life situation can affect health?
Access to medicine or preventive measures.
Fill in the blank: If stress can affect your health, why do we have _______.
[exams]
True or False: Understanding communicable and non-communicable diseases is important for exams.
True
What are risk factors?
Things linked to an increased chance of getting a certain disease
Risk factors do not guarantee that someone will get the disease.
What can risk factors be part of?
They can be part of a person’s lifestyle or substances in a person’s environment or body
Examples include exercise levels, air pollution, and asbestos fibers.
What is the relationship between lifestyle factors and non-communicable diseases globally?
Non-communicable diseases are more common in developed countries
This is due to higher income allowing access to high-fat foods.
What lifestyle factors are associated with cardiovascular disease, obesity, and Type 2 diabetes in poorer areas?
Smoking, poor diet, and lack of exercise
These factors contribute to higher disease prevalence in impoverished regions.
What are benign tumors?
Tumors that stay in one place, do not invade surrounding tissues, and are not cancerous
They are generally considered less harmful than malignant tumors.
What are malignant tumors?
Tumors where cells can break away and spread to other parts of the body
Malignant tumors are cancerous and more dangerous.
Name a direct risk factor that can cause diseases.
Smoking
It can cause cardiovascular disease, lung disease, and lung cancer.
What is a carcinogen?
A substance that causes cancer
Examples include ionizing radiation from X-rays.
What are some indirect risk factors for cardiovascular disease?
Lack of exercise and a high-fat diet
They contribute to high cholesterol levels which can lead to the disease.
What is one impact of non-communicable diseases on individuals?
Lower quality of life or shorter lifespan
These diseases significantly affect personal well-being.
What financial impacts do non-communicable diseases have?
High costs for researching and treating diseases, and potential loss of income for families
The economic burden can extend to national levels.
What is a lifestyle risk factor associated with obesity?
Poor diet
A poor diet can lead to obesity, which is a risk factor for Type 2 diabetes.
Fill in the blank: The _______ can cause health problems for the unborn baby.
Smoking and drinking alcohol
True or False: All risk factors directly cause diseases.
False
Some risk factors correlate with diseases without directly causing them.
What are some lifestyle factors identified as risk factors?
- Smoking
- Obesity
- Viral infections
- UV exposure
These factors can increase the risk of developing various diseases.
What are some lifestyle factors identified as risk factors?
- Smoking
- Obesity
- Viral infections
- UV exposure
These factors can increase the risk of developing various diseases.
What causes cancer?
Uncontrolled cell growth and division
This leads to the formation of tumours.
What is a tumour?
A mass of cells resulting from uncontrolled growth
Tumours can be benign or malignant.
What are benign tumours?
Masses of abnormal cells that stay in one place
They do not invade other parts of the body and are not cancerous.
What characterizes malignant tumours?
They spread to other parts of the body
Malignant tumours are dangerous and can be fatal.
What can happen to cells from malignant tumours?
They can break off and travel in the bloodstream
This can lead to the formation of secondary tumours.
List four risk factors that can increase the chance of developing cancer.
- Smoking
- Obesity
- Viral infection
- UV exposure
How does smoking relate to cancer?
Smoking is linked to many types of cancer
It is considered a significant lifestyle factor.
What is the relationship between obesity and cancer?
Obesity has been linked to many different cancers
It is recognized as a lifestyle risk factor.
How can viral infections affect cancer risk?
Some viruses can increase the chances of developing certain types of cancer
This highlights the importance of monitoring viral health.
What effect does UV exposure have on cancer risk?
It has been linked to an increased chance of developing skin cancer
UV radiation from the Sun is a significant risk factor.
What role do genetic factors play in cancer risk?
Inherited faulty genes can increase cancer likelihood
Genetic predisposition is a critical aspect of cancer risk.
What advancements have improved cancer survival rates?
- Improved treatments
- Earlier diagnosis
- Increased screening
- Greater awareness of risk factors
True or False: All tumours are cancerous.
False
Only malignant tumours are considered cancerous.
Fill in the blank: Benign tumours do not _______ other parts of the body.
[invade]
What is a secondary tumour?
A tumour formed from cells that have spread from a primary malignant tumour
This occurs when cancer cells travel through the bloodstream.
What are the main organs of a plant?
Stems, roots, and leaves
These organs work together to form organ systems.
What is the function of plant organs?
To transport substances around the plant
This includes water, minerals, and food.
What is epidermal tissue?
Covers the whole plant
It serves as a protective layer.
Where does most photosynthesis occur in a leaf?
Palisade mesophyll tissue
This tissue contains chloroplasts for photosynthesis.
What is the role of spongy mesophyll tissue?
Contains air spaces for gas diffusion
It enhances the rate of gas exchange in the leaf.
What do xylem and phloem transport?
Water, mineral ions, and food
They are essential for nutrient distribution in the plant.
Where is meristem tissue found in a plant?
At the growing tips of shoots and roots
It is responsible for plant growth.
What is the function of the upper epidermis in a leaf?
Allows light to pass through
It is transparent to facilitate photosynthesis.
What is the purpose of guard cells?
Control the opening and closing of stomata
This regulates gas exchange in response to environmental conditions.
What is the function of stomata?
Allow gases to diffuse in and out of the leaf
They play a crucial role in photosynthesis and respiration.
What do xylem and phloem provide to the leaf?
Water and nutrients, and remove glucose
They also support the leaf structurally.
Fill in the blank: The leaf is where _______ and gas exchange happens in a plant.
photosynthesis
True or False: The palisade layer of a leaf is located at the bottom.
False
The palisade layer is near the top of the leaf to maximize light absorption.
What is the relationship between the structures of leaf tissues and their functions?
Structures are adapted to optimize their specific functions
For example, the upper epidermis is transparent to allow light for photosynthesis.
What are phloem tubes made of?
Elongated (stretched out) living cells
Phloem tubes are responsible for transporting food substances in plants.
What is cell sap?
A liquid made up of the substances being transported
Cell sap is found within phloem tubes.
What features do the end walls of phloem cells have?
Pores (small holes) to allow cell sap to flow through
This facilitates the movement of nutrients within the plant.
What substances do phloem tubes transport?
Food substances (e.g. dissolved sugars) and water
These substances are transported for immediate use or for storage.
In which directions do phloem tubes transport substances?
Both directions
This bidirectional transport is part of the process known as translocation.
What is the process called that involves the transport of food substances in phloem?
Translocation
Translocation allows for the distribution of nutrients throughout the plant.
What are xylem tubes made of?
Dead cells
Xylem cells are specifically designed to transport water and minerals.
What is a key structural feature of xylem cells?
They are joined together with a hole down the middle
This structure allows for the efficient flow of water.
What material strengthens xylem tubes?
Lignin
Lignin provides structural support to xylem cells.
What do xylem tubes carry from the roots to the stem and leaves?
Water and mineral ions
This transport is crucial for the plant’s hydration and nutrient uptake.
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 causes transpiration?
Evaporation and diffusion of water from a plant’s surface
Transpiration primarily occurs through the leaves.
What happens to water during evaporation?
Water turns from a liquid into a gas
This process occurs primarily at the leaves of the plant.
How does transpiration create a water shortage in leaves?
Water evaporates from the leaves, causing a slight shortage
This shortage triggers more water to be drawn up from the roots.
What is the constant stream of water through the plant called?
Transpiration stream
This stream is vital for plant hydration and nutrient distribution.
True or False: Phloem only transports substances upwards.
False
Phloem transports substances in both directions, unlike xylem.
Fill in the blank: Xylem transports water and minerals _______.
upwards
This upward movement is crucial for plant growth and function.
What is transpiration rate affected by?
Four main things:
* Air Flow
* Temperature
* Humidity
* Light Intensity
These factors influence the rate of diffusion of water.
How does air flow affect transpiration?
The more windy it is, the faster transpiration happens due to the removal of water vapor around the leaf.
What effect does temperature have on transpiration?
The warmer it is, the faster transpiration occurs because water particles have more energy.
How does humidity influence transpiration rate?
High humidity means less difference between inside and outside water vapor, slowing diffusion.
What is the relationship between light intensity and transpiration?
Brighter light increases transpiration rate; stomata close in the dark, reducing water escape.
What are guard cells and their function?
Guard cells surround stomata and control their size to regulate gas exchange and water loss.
What happens to guard cells when the plant has lots of water?
They fill with water and become fat, causing stomata to open for gas exchange.
What occurs to guard cells when the plant is short of water?
They lose water and become floppy, leading to the closing of stomata.
Where are stomata typically located on leaves?
There are usually more stomata on the bottoms of leaves than on the tops.
Why are there more stomata on the underside of leaves?
The lower surface is cooler, reducing water loss.
What is the plural form of stoma?
Stomata.
Fill in the blank: The process of water vapor escaping from plants is called _______.
Transpiration.
List the four main factors affecting transpiration.
- Air Flow
- Temperature
- Humidity
- Light Intensity
Each factor influences the rate of diffusion of water.
What effect does drier air have on transpiration?
The drier the air, the faster transpiration occurs.
