B2 Organisation Flashcards
<p>What is a <b>tissue</b>?</p>
<p>A tissue is a group of similar cells that act together to perform a function</p>
<p>What are <b>Epithelial Tissue</b>?</p>
<p>Epithelial tissue is a lining on the outer suface of organs and blood vessels</p>
<p>What is the <b>basic unit</b> of life?</p>
<p><b>Cells</b></p>
<p>What are <b>Organs?</b></p>
<p>Organs are groups of distinct tissues that work together to perform a specific function</p>
<p><b>What are Organ Systems</b>?</p>
<p>Organ systems are groups of organs that work together to perform a particular role</p>
<p>What is an <b>Organism</b>?</p>
<p>An Organism is the highest level of organisation in a multicellular organism and consists of multiple organ systems</p>
<p>What are the levels of organisation in multicellular organisms?<i>(Starting with the least complex)</i></p>
<p></p>
<ol>
<li>Cell</li><li>Tissue</li><li>Organ</li><li>Organ System</li><li>Organism</li>
</ol>
<p>What are the Organs in the <b>Digestive System</b></p>
<p></p>
<ul><li>Large Intestine</li><li>Small Intestine</li><li>Liver</li><li>Stomach</li><li>Glands</li></ul>
<p>What is an <b>enzyme</b>?</p>
<p>An enzyme is a protein that increases the rate of reaction</p>
<p>Enzymes are also known as <b>biological catalysts</b></p>
<p>What is the <b>active site</b> of an enzyme?</p>
<p>The active site of an enzyme binds a specific <b>substrate</b></p>
<p>Describe the <b>lock and key mechanism</b> of enzyme action</p>
<p>The active site is like a lock and the substrate is a key</p>
<p>In the same way, there is usually only one enzyme for every substrate</p>
<p>What does <b>denatured</b> mean?</p>
<p>When an enzyme is denatured, it means its structure is altered and can no longer catalyse a reaction</p>
<p>Which <b>factors</b> denature an enzyme?</p>
<ul><li>High Temperatures</li><li>Changing pH away from optimum pH</li></ul>
<p>What are digestive enzymes used for?</p>
<p>Digestive enymes are used to break down large food molecules for absorption</p>
<p>Where is <b>bile</b> produced?</p>
<p>Bile is produced in the Liver</p>
<p>Where is bile stored?</p>
<p>Bile is stored in the Gall Bladder</p>
<p>What are the uses of bile?</p>
<ul><li>Emulsification</li><li>Neutralisation of HCl Acid</li></ul>
<p>What is Emulsification?</p>
<p>Emulsification is a process that breaks up fats into timy droplets</p>
<p>Why is Bile used for <b>neutralisation</b>?</p>
<p>Enzymes in the small intestine best operate in Alkaline conditions</p>
<p>The bile neutralises Hydrochloric Acid from the stomach to stop these enzymes from becoming denatured</p>
<p>What is <b>Amylase</b>?</p>
<p>Amylase is a type of <b>carbohydrase</b> that breaks down starch in our bodies</p>
<p>What does amylase break down starch into?</p>
<p>Starch → Maltose (+ other simple sugars)</p>
<p>Where are the <b>action sites</b> of Amylase?</p>
<p>The action sites of amylase are:</p>
<ul><li>The Small Intestine</li><li>The Mouth</li></ul>
<p>Where is Amylase produced from?</p>
<p>Amylase is produced in:</p>
<ul><li>Pancreas</li><li>Salivary Glands</li></ul>
<p>What is the enzyme that breaks down <b>Proteins</b></p>
<p>Protease</p>
What does Protease break Proteins into?
Protein → Amino acids
What are the action sites of protease?
The action sites of protease are:
- Small Intestine
- Stomach
Where is Protease produced?
Protease is produced in the:
- Pancreas
- Stomach
What is Lipase?
Lipase is a digestive enzyme that breaks down Lipids
What does Lipase break Lipids into?
Lipid → glycerol + 3 fatty acids
Where is Lipase produced?
Lipase is produced in the:
- Small Intestine
- Pancreas
What are the 3 types of blood vessels around the body?
The 3 blood vessels around the body are:
- Veins
- Arteries
- Capillaries
What is the order in which food passes through the digestive system?
- Mouth
- Oesophagus
- Stomach
- Small Intestine
- Large Intestine
- Rectum
- Anus
What is the function of the mouth in digestion?
To mechanically break up food into smaller pieces to increase surface area (Mechanical Digestion)
What are two functions of saliva in digestion?
- To moisten food to allow easier swallowing
- To start chemical digestion by containing salivary amylase
What is the function of stomach acid?
To kill potentially pathogenic microorganisms in food
What is the function of the small intestine?
To absorb carbohydrates, lipids, amino acids, vitamins and mineral ions from digested food
What are the adaptions of the small intestine and the cell lining of the small intestine that aid the absorption of digested molecules?
- Small intestine has structures called villi which increase surface area
- Epithelial cells lining the villi have microvilli on their surface which further increase surface area
What is the function of the large intestine?
To absorb water from digested food
What is the function of the liver in digestion?
To produce bile, an emulsifier of lipids and neutraliser of Hydrochloric Acid
What is the function of the gall bladder?
To store bile until it can be released into the small intestine
What is the function of the rectum?
To store undigested material before excretion
What is a substrate?
A molecule or atom which is acted upon by an enzyme
How does an enzyme “recognise” its specific substrate?
A complementarily-shaped active site – a region on the enzyme which fits the substrate.
Name two environmental conditions that can change an enzyme’s active site
- pH (either higher or lower than optimum)
- Higher than optimal temperature
Where is carbohydrase produced?
- Salivary glands
- Pancreas
- Small Intestine
What do carbohydrases break down and what is produced?
Carbohydrates to simple sugars (e.g. amylase breaks down starch to glucose)
Where is protease produced in the body?
- Stomach
- Pancreas
- Small Intestine
What do proteases break down and what is produced?
Proteins to amino acids
Name where lipase is made in the body
- Stomach
- Pancreas
- Small Intestine
What do lipases break down and what is produced?
Lipids (fats) to 3 fatty acids and 1 glycerol
What are the products of digestion used for?
To build new carbohydrates, lipids and proteins
How does bile help the action of lipase?
- Provides alkaline conditions by neutralising acid from the stomach
- Emulsifies fat to form small droplets with a larger surface area
What is the Benedict's test and how do you carry it out?
The Benedict's test is for testing if there is sugar in food samples
- Add Benedict's reagent
- leave in a hot water bath (above 60°C) for 5 minutes
- if it turns orange/brick red, it contains sugar
What is the Biuret test and how do you carry it out?
For testing if there is protein in food samples. Add Biuret reagent (blue liquid). If it turns lilac, protein is present
Which food test can be carried out with iodine?
Testing for the presence of starch. Add iodine (reddish brown) drops to food sample. If it turns blue/black, it contains starch
Which system transports substances around the body?
The circulatory system
What is the heart?
An Organ that pumps blood around the body
What is the function of the heart?
Pump blood around the body
What are the walls of the heart made from?
Muscle Tissue
Name the two types of chambers in the heart
Atria and Ventricles
Which are the upper chambers of the heart?
Atria
Which are the lower chambers of the heart?
Ventricles
Where do the atria force blood upon contraction?
Into the Ventricles
Where do the ventricles force blood upon contraction?
Out of the Heart
What is the job of the heart valves?
To prevent backflow of blood in the heart
To where does blood flow after leaving the right hand side of the heart?
To the Lungs
To where does blood flow after leaving the left hand side of the heart?
The rest of the body
Through which blood vessel does blood flow away from the heart?
Arteries
Through which blood vessel does blood flow back into the heart?
Veins
Name the blood vessel by which blood leaves to the rest of the body
Aorta
Name the blood vessel by which blood arrives back from the rest of the body
Vena Cava
Name the blood vessel by which blood leaves the heart to the lungs
Pulmonary Artery
Name the blood vessel by which blood leaves the lungs to go back to the heart
Pulmonary Vein
Which type of blood vessels have thick walls containing muscle tissue and elastic fibres?
Arteries
Which blood vessels have thinner walls and contain valves?
Veins
Name two key adaptations of capillaries
- Very thin (only one cell thick) to reduce distance diffusion has to occur across
- Very narrow to reduce distance diffusion has to occur across
Where is the “natural” pacemaker of the heart located?
Right Atrium
Where are the lungs located?
Upper Part of the Body - Thorax
What protects the lungs?
The Ribcage
What separates the lungs from the abdomen (lower part of body)?
The Diahpragm
Which gas diffuses into the bloodstream?
Oxygen
Which gas diffuses out of the bloodstream?
Carbon Dioxide
Name the two structures which branch off from the trachea
Bronchi
Name the structure which branch off from the bronchi
Bronchiole
What are the small gas exchange structures in the lungs called?
Alveoli
Describe four adaptations alveoli have to make them well suited for gas exchange
- Thin walls (one cell thick)
- Extensive capillary network covering the surface of each alveolus
- Efficient movement of blood through capillaries to maintain a concentration gradient for diffusion of oxygen & carbon dioxide
- Folded inner surface to give a large surface area
What is the liquid part of blood called?
Plasma
What are the three main cell types found in blood?
- Red Blood Cells
- White Blood Cells
- Platelets
What does blood plasma transport from the organs to the lungs?
Carbon Dioxide
What does blood plasma transport from the small intestine to other organs?
Soluble products of digestion
What does blood plasma transport from the liver to the kidneys?
Urea
What do red blood cells transport?
Oxygen
How do Red Blood Cells transport Oxygen?
When there is a high concentration of oxygen, oxygen binds with haemoglobin in Red Blood Cells and forms Oxyhaemoglobin
When there is a low conentration of oxygen, the oxygen is released from the haemoglobin
How are Red Blood Cells adapted to make the transfer of oxygen more efficient?
- They contain haemoglobin - a red protein that combines with oxygen
- They have no nucleus so they can contain more haemoglobin
- They are small and flexible so that they can fit through narrow blood vessels
- They have a biconcave shape (flattened disc shape) to maximise their surface area for oxygen absorption
In the lungs, which reversible reaction occurs?
Haemoglobin + oxygen ⇆ oxyhaemoglobin
What do white blood cells do?
Defend the body against microorganisms
What do platelets do?
Help clot the blood at wound sites
What are the coronary arteries?
Blood vessels that supply the heart muscle tissue
What occurs in Coronary Heart Disease (CHD)?
The coronary arteries become blocked with fatty deposits, narrowing them
Why is Coronary Heart Disease a problem?
Reduces the flow of blood to the heart, therefore reducing the supply of oxygen, glucose and pickup of carbon dioxide
How do stents treat Coronary Heart Disease (CHD)?
Re-opens the blocked coronary artery, restoring blood flow
How do statins treat Coronary Heart Disease (CHD)?
Decreases the blood concentration of cholesterol, which reduces build-up of fatty deposits in the coronary arteries
Why are faulty heart valves life-threatening?
Allows backflow of blood
Name two sources of replacement heart valves
- Mechanical
- Biological - Pigs/Sheep
Describe a treatment used in the case of total heart failure
Heart Transplant
Name a risk of surgical intervention in heart disease
Infection
When would an artificial heart be used?
- To allow the heart to rest and recover
- To keep the patient alive whilst they wait for a transplant
What is health?
The state of physical and mental well-being
What are the two types of disease?
Communicable (caused by a pathogen) and non-communicable
Give an example of how different diseases can interact
- Defects in the immune system mean that an individual is more likely to suffer from infectious diseases
- Viruses living in cells can be the trigger for cancers
- Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma
- Severe physical ill health can lead to depression and other mental illness
Name three factors, other than pathogens, which can influence health
- Diet
- Stress
- Life situations
What is a risk factor?
A factor linked to an increased rate of disease
Give two general examples of a risk factor
- The lifestyle of a person
- Substances in the person’s body or environment
What is meant by "correlation does not imply causation"?
Just because two variables are correlated (one increases as the other increases), doesn't mean that one causes the other e.g. ice cream sales and number of sunburnt people
Some risk factors have had a causal mechanism proven for some diseases. Name three examples
- The effects of diet, smoking and exercise on cardiovascular disease
- Obesity as a risk factor for Type 2 diabetes
- The effect of alcohol on the liver and brain function
- Carcinogens, including ionising radiation, as risk factors in cancer
- The effects of smoking and alcohol on unborn babies
- The effect of smoking on lung disease and lung cancer
Most diseases are termed “multi-factorial”. What does this mean?
Multiple risk factors contributing to the person developing the disease
What is cancer?
Cancer is a group of diseases, where changes in cells lead to uncontrolled growth and division of cells
How do cancers develop?
DNA in cells is changed (mutated)
What is a benign tumour?
A growth of abnormal cells which is contained in one area within the body and will not invade other body parts
What is a malignant tumour?
A growth of abnormal cells which invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours
Name some main lifestyle risk factors for cancer
Two from:
|- Smoking
- Excessive alcohol use
- Obesity
- UV Exposure
- Genetics
Name six plant tissues
- Epidermal
- Palisade Mesophyll
- Spongy Mesophyll
- Xylem
- Phloem
- Meristem
Name three plant tissues
Any three from:
- The epidermis
- The Palisade Mesophyll
- The Spongy Mesophyll
- The Xylem
- The Phloem
- Guard Cells
What is transpiration?
The movement of water (and minerals) from the roots to the leaves. Water eventually leaves the leaves via evaporation
Name four factors which affect the rate of transpiration in plants
- Temperature
- Humidity
- Air movement
- Light intensity
How does temperature affect rate of transpiration?
Higher temperature increases transpiration rate as water evaporates quicker
How does humidity affect rate of transpiration?
Higher humidity decreases transpiration rate. It increases the amount of water in the air so makes it difficult for water to evaporate
How does wind or air flow affect rate of transpiration?
More wind increases transpiration rate (it maintains a steep concentration gradient) as it carries water away from the leaves
How does light intensity affect rate of transpiration?
More light increases transpiration rate as it increases evaporation rates
Name the equipment used to estimate transpiration rate
Potometer: a device that measures the volume of water uptake in a plant shoot
Name three plant organs
- Roots
- Stem
- Leaves
What is translocation?
The movement of sugars from the leaves to the rest of the plant
Describe the adaptations of xylem tissue
- Hollow tubes strengthened by lignin (Lignin strengthens and waterproofs the wall)
- Dead cells to maximise space for water
- No end cells, so can have a long tube
Describe the adaptations of phloem tissue
Elongated cells with pores in the end cell walls to aid the movement of dissolved sugars
What is the role of stomata and guard cells?
To allow gas exchange and control water loss
What food test do you do to test for the presecence of Sugar?
Bennedict's Solution test
What is the method for Bennedict's solution test for sugar?
Add Benedict's reagent to the substance and heat for 2 minutes
If sugar is present, the colour will turn green, yellow or red if sugar is present
What is the food test to test for the presence of Lipids?
Ethanol Test
How do you know lipids are present in the ethanol test?
The solution turns cloudy when lipids are present
What is the food test to test for the presence of Protein?
Biuret test
How do you know protein is present in the Biuret test?
The solution turns mauve / lilac if protein is present
What is the food test to test for the presence of starch?
Iodine Test
How do you know starch is present in the Iodine test?
The solution turns blue-black
Why do veins have thinner walls than arteries?
Veins transport blood with lower pressure so don't need thick walls to withstand high pressure
Why do veins have a larger lumen than arteries?
The low pressure in veins slows blood flow. Veins have a larger cross-section (lumen) to counteract this
Why do veins have valves?
Veins have valves to prevent the backflow of blood
How is a malignant tumor spread?
A malignant tumor is spered through the bloodstream and lymph system
Why are benign tumors unable to spread to other parts of the body?
Benign tumors can't spread to other parts of the body as they surrounded by a membrane which localises them to a single region of the body
What is the problem with leaky valves?
Leaky valves allow the backflow of blood. This creates a strain on the heart
What is the problem with valves that don't fully open?
Valves that don't open fully obstruct blood flow. This means a greater force is required for blood to flow. Therefore, it causes a strain on the heart
What are the benefits of Artificial Hearts?
- Artificial hearts are unlikely to be rejected by the patient’s immune system, so immunosuppressant drugs (prevent rejection) are unnecessary
- Artificial hearts can also be used to provide the heart with some rest to allow it to recover
What are the drawbacks to Artificial Hearts?
- Artificial hearts can result in long and expensive stays in hospital
- They can also cause blood clotting, which can potentially lead to strokes
What are the potential disadvantages of using transplanted organs to treat heart disease?
- The transplanted organ may be rejected
- Need to take immunosuppressant drugs which makes them more susceptible to contracting another disease
What is Meristem tissue?
Meristem tissue is the undifferentiated cells of a plant capable of specialising into different plant cells
What is the function of the Palisade Mesophyll in Plants?
The Palisade Mesophyll or Palisade layer is where photosynthesis takes place
How are Palisade cells adapted to perform there function?
Palisade cells are packed together and and have lots of chloroplasts to maximise energy transfer in photosynthesis
How is the spongy mesophyll layer adapted to perform its function?
There are lots of air spaces which increases surface area which, in turn, increases gas exchange throughout the leaf
What is the function of the upper epidermis?
The upper epidermis or epidermal layer covers and protects the outer surface of leaves
How is water taken in by a plant?
- Root hair cells absorb water from the soil via osmosis (movement of water from a dilute solution to a concentrated solution)
- After being absorbed by the root hair cells, the water are transported in xylem vessels up the stem and into the leaves
- Once it reaches the leaves, the majority of water evaporates and the water vapour diffuses out (is lost) through open stomata
- This loss of water from the leaves is known as transpiration and helps to pull water up from the roots
How are mineral ions taken in by a plant?
- From the root, mineral ions are taken up by active transport (movement of ions and molecules across a cell membrane to an area of higher concentration)
- After being absorbed by the root hair cells, the minerals are transported in xylem vessels up the stem and into the leaves
What is the the method to measure the rate of transpiration?
A Potometer is used to measure the rate of transpiration
- As water is lost through the plant’s leaves, the air bubble moves
- The speed of the bubble's movement shows the rate of water uptake
- This is only an estimation (guess) as a small amount of the water taken up by the shoot is used in the leaves
How is translocation different to transpiration?
Translocation is bidirectional (movement is both up and down the plant) whereas, transpiration can only move up
How are root hair cells adapted for its function?
- Lots of mitochondria for active transport of minerals
- Long projections to increase surface area
