B2 Cell Organisation Flashcards
Define Cell.
Building block of life.
Define Specialised Cell.
A cell adapted to carry out a specific function. The process by which cells become specialise is called differentiation.
What is the job of the systems in large multicellular organisms?
Exchanging and transporting material.
Define Tissue.
A group of similar cells that work together to carry out a particular function.
Define Organ.
A group of tissues that work together to perform a certain function.
Define Organ systems.
A group of organs working together to perform a particular function.
What organs are in the digestive systems (in the order they come).
The digestive system begins in the mouth. It is followed by the salivary gland, pancreas, stomach, liver, small intestine, large intestine,rectum and anus.
What is an enzyme?
An enzyme is a natural catalyst, they are large proteins made up of amino acids.
What is a catalyst?
A catalyst is a substance which increases rate of reaction without being changed or used up during the reaction.
What is the lock and key model?
The lock and key model means that enzymes only ever fit one type of substrate. Enzyme’s active sites are the right size and chemically accurate to fit a specific substrate.
What does the graph of optimum temperature look like?
It gradually increases and then falls suddenly. The highest point is optimum temperature.
What is meant by optimum temperature?
Optimum temperature is the best temperature for enzyme activity and thus increases rate of reaction.
What is meant by optimum pH?
Optimum pH is the best acidity for enzyme activity and thus increases rate of reaction.
What does the graph of optimum pH look like?
It gradually increases and then falls gradually. The highest point is optimum pH.
How do you calculate rate of reaction?
Rate = 100/time
How do you test for starch?
Iodine - Blue-black
You drop a few drops of iodine on the food, if it turns black-blue, it contains starch, otherwise, there is no starch.
How do you test for sugar?
Benedict’s -Orangey red
Add equal quantities of water and Benedict’s solution to the food sample in the test tube, place it in a tub of 95 degree centigrade water bath. If the liquid turns cloudy orange or brick red starch is present.
How do you test for protein?
Biurets - Purple
Place the food sample into a test tube, add water to the tube and stir to mix, add an equal volume of potassium hydroxide solution to the tube and stir, then add two drops of copper sulfate solution and stir for two minutes.
Proteins are detected using Biuret reagent . This turns a mauve or purple colour when mixed with protein.
How do you test for fats?
Ethanol (Sudan III) - Cloudy
Place the food sample into a test tube and add ethanol and an equal volume of distilled water to the tube, cover and shake the tube vigorously. Allow the contents to settle. A milky-whiteemulsion forms if the test substance contains lipids.
What does it mean if an enzyme i denatured?
This is when (due to incorrect pH, temperature) the active site on the enzyme changes becoming a wrong fit.
What enzyme breaks down starch and into what product?
Amylase breaks down starch, it breaks it down, first into maltose and then glucose and other sugars.
Amylase breaks down starch, where is it produced?
Amylase is produced in the salivary glands, pancreas and small intestine.
What enzyme breaks down protein and into what product?
Protease breaks down proteins into amino acids.
Protease breaks down proteins, where is it produced and what is the product of this reaction?
Protese is produces in the stomach (called pepsin), pancreas (called trypsin) and the small intestine (called peptidase).into amino acids.
What enzyme breaks down lipids and into what product?
Lipase breaks down lipids into glycerol and fatty acids.
What is the job of bile?
Bile neutralises acids leaving the stomach and emulsifies fat (breaks fat into smaller pieces with a larger surface area so it digests faster).
What is the job of the salivary glands?
Salivary glands produce salivary amylase which breaks down starch in the mouth.
What is the job of the gullet or oesophagus?
Transporting food for digestion and mechanical breaking down of food through muscular contractions.
What is the job of the mouth?
The mouth is where salivary amylase is released into the mouth to break down protein and where technical digestion of all food occurs through biting.
What is the job of the stomach?
As well as churning food, the stomach is also responsible for breaking down protein using the protease, pepsin. It also produces hydrochloric acid to kill bacteria and to ensure the correct pH for pepsin to work..
What is the job of the liver?
The liver produces bile. Bile neutralises stomach acids and emulsifies fat.
What is the job of the gall bladder?
The gall bladder is where bile is stored and then releases it into the small intestine.
What is the job of the pancreas?
The pancreas produce protease, amylase and lipase enzymes. It releases these into the small intestine.
What is the job of the Large Intestine?
Where excess water from food is absorbed.
What is the job of the Small Intestine?
Produces digestive enzymes and absorbs digested food into the blood stream.
What is the job of the Rectum?
Where faeces is stored before being excreted by the anus.
What is the thorax?
Upper part of your body
Describe which organs air goes through before gas exchange
pathway of air
Nasal cavity/ Mouth Trachea Bronchus Bronchiole Alveoli
What protects the lungs?
Pleural membranes
Ribs
What is the job of intercostal muscles?
To assist in inhalation by moving the ribs upwards and outwards to increase the chest cavity.
What is the job of the diaphragm?
To assist in inhalation by pulling the bottom of the lungs down to increase the chest cavity
How are alveoli specialised to do their jobs?
- Large Surface Area
- Many of them
- Good Blood Supply
- Only 1 cell thick
What occurs in the alveoli?
Gas exchange.
Describe the process of gas exchange during inhalation.
Oxygen enters the alveoli during inhalation,
Blood entering the network of capillaries leading up to the alveoli are deoxygenated,
Oxygen diffuse across the walls of the alveoli and capillary from an area of high concentration to an area of low concentration to be used in respiration.
Describe the process of gas exchange during exhalation.
Blood entering the network of capillaries leading up to the alveoli carry waste products such as carbon dioxide,
There is little or no carbon dioxide in the lungs,
Carbon dioxide diffuse across the walls of the capillaries and alveoli from an area of high concentration to an area of low concentration to be excreted.
What are the four elements of blood?
- Red Blood Cells
- White Blood Cells
- Platelets
- Plasma
What is the function of red blood cells?
Carry oxygen
What allows red blood cells to carry oxygen?
Oxygen connects to haemoglobin to create oxyhemoglobin.
What is the function of white blood cells?
To fight infections
What is the function of platelets?
To create blood clots
What is the function of plasma?
To carry waste products
Why is the circulatory system called a double circulatory system?
It consists of two full circulations
See Figure 3
Starting in as deoxygenated and entering the heart, describe the pathway of blood
Deoxygenated blood enters through the vena cava and into the right atrium
At the first pump a valve opens and allows it into the right ventricle
On the second pump it is forced out of the heart through the pulmonary artery
This then reaches the lungs where it is oxygenated
Oxygenated blood then returns to the heart through the pulmonary vein and into the left atrium
At the first pump a valve opens and allows it into the left ventricle
On the second pump it is forced out of the heart through the aorta, this takes it to the rest of the body
Blood returns to the heart deoxygenated
(See Figure 4)
What causes the heart to pump twice?
There are 4 valves, in the first pump to open and in the second the other two do
Describe the function of valves
They prevent blood travelling backwards in the system
What controls the speed of heart beats?
A pacemaker
Describe how a pacemaker works
It produces a small electric impulse which spreads around the muscle causing it to contract
Describe a pacemaker (physically)
A small group of cells in the wall of the right atrium
Describe a solution for when a patients heartbeats are irregular
Artificial pacemaker
What is the function of the arteries?
Take blood away from the heart
What is the function of veins?
Take blood to the heart
What is the function of capillaries?
Take blood deep into muscle tissue and material exchange within these tissues
What makes arteries good for their function?
Thick outer wall
Elastic muscle wall to deal with high pressure
(See Figure 5)
What pressure is the blood carried by arteries?
Very High
What makes veins good for their function?
Very large lumen
Valves to deal with lack of pressure
(See Figure 5)
What pressure is the blood carried by veins?
Very Low
What makes capillaries good for their function?
Only 1 cell thick
Permeable membrane
Very small (can get everywhere)
(See Figure 5)
What is a lumen?
The hole in the middle of a blood vessel that blood travels through
(See Figure 5)
Define permeable
Substances can pass through
How many red blood cells fit though a capillary at any 1 time?
1
How are red blood cells specialised for their function?
Biconcave disc shape ( large surface area)
No Nucleus (more space)
Haemoglobin (red pigment which attaches to oxygen)
What is the process where white blood cells engulf pathogens?
Phagocytosis
What are the three ways white blood cells fight infection?
Phagocytosis
Antibodies
Antitoxins
How are white blood cells adapted for phagocytosis?
Can change shape
What are platelets made of?
Fragments of cell with no nucleus
Name 7 materials carried by plasma
Glucose Amino Acids Carbon Dioxide Urea Hormones Proteins Antibodies Antitoxins
What is the cause of cardiovascular disease?
Fatty Build-up in the coronary arteries
What is a stent?
A tube inserted inside an artery so that fatty build-up is squashed, opening the artery and lowering the risks involved with coronary heart disease
(textbook page 37)
What are complications involved with stents operations?
Complications during operation:
- hear attack
Infection from the surgery
Thrombosis (when a blood clot form near the stent)
What are the two types of cholesterol?
HDL- good cholesterol
LDL - bad cholesterol
What is cholesterol?
An essential lipid
What does too much LDL cholesterol cause?
Fatty deposits inside arteries
What do fatty deposits in the arteries cause?
Coronary Heart Disease
What is a statin?
A drug which reduces LDL cholesterol and increases HDL cholesterol and thus slows the forming of fatty deposits in the arteries
What is the function of statins?
Lower the risks of strokes, coronary heart disease and heart attack and
What are the disadvantages of statins?
Must be taken regularly
Not instant
Negative side effects
What could cause the prescription of a heart transplant?
Heart Failure
What is a donor organ?
The donated organ of a person who is recently deceased
What could be done if someone requires a heart transplant but no donor organs are currently available?
An artificial heart could be temporarily installed
What is an artificial heart?
A mechanical device which (temporarily) pumps blood around a persons body.
What are the advantages of an artificial heart?
They will not be rejected by the body as they are made of plastic/ metal and not detected as foreign
Can give the persons real heart time to heal
What are the disadvantages of an artificial heart?
Surgery can cause bleeding and infection
Can wear out - do not function as well as natural hearts
Drugs must be taken to thin the blood
What can cause heart valves to become weakened or damaged?
Heart attack
Infection
Age
What happens to damaged heart valves?
The tissue may to stiffen or won’t open
Or, it could become leaky allowing blood to flow in both directions
What are biological valves?
Valves made from other humans or mammals (cows or pigs)
What are mechanical valves?
Man-made valves
What can be a complication of replacing a valve?
Problems can be caused with blood clots
Major surgery
What can we use to keep someone (temporarily) alive if they loose a lot of blood?
Artificial Blood
What is artificial blood made of?
Saline (salt solution) which can pump around the remaining red blood cells
What does artificial blood ideally give the patient time to do?
Produce new red blood cells
If they cannot produce enough they may need a blood transfusion
Define Health
Complete state of social physical and mental wellbeing
Define communicable disease
A disease that can be spread from person to person or between animals and people
Define non-communicable disease
A disease that can not be spread from person to person or between animals and people
What does it mean in diseases interact?
If you have one disease and are infected by another, chances are your body can’t deal with both at the same time and thus both worsen
What three factors affect your health?
Fitness
Social life
Mental stability
What is a risk factor?
Something which increases a persons chances of developing or contracting a disease
How can lifestyle be a risk factor to disease?
The amount of exercise they do
What they eat
How much sleep they get
How can the environment be a risk factor to disease?
Air pollution
Sound pollution
How can substances that get into the body be a risk factor to disease?
(lead or asbestos)
These could be physically damaging
Could be toxic
What does it mean if a risk factor is a direct cause for a disease?
That this risk factor is the main (or only) reason that this disease has been contracted
The risk factor has caused the disease to occur
What are the socioeconomic disadvantages of non-communicable disease?
They tend to be very dangerous
They tend to be very long
Treatment tends to be very expensive
What are tumours?
Uncontrolled cell division
What are the two types of tumour?
Benign
Malignant
Describe Benign tumors
Grow until they have more room
Stay in one place and are thus not cancerous
Usually not dangerous
Describe Malignant tumours
Cells break up and travel through the blood stream to neighbouring healthy tissue
Dangerous and can be fatal
These are cancers
What is a risk factor for lung cancer?
Smoking
What is a risk factor for bowel, liver or kidney cancer?
Obesity
What is a risk factor for skin cancer?
UV Exposure
What is a risk factor for liver cancer?
Viral Infections
such as hepatitis B/C
What are genetic risk factors?
When you are more likely to contract a disease because you have inherited faulty genes
What is the function of epidermal tissue?
Acts as a barrier defence against pathogens
in both animals and plants
What is the function of the palisade mesophyll tissue?
Contains many chloroplasts and is where photosynthesis occurs
What is the function of the spongy mesophyll tissue?
Allows gasses to diffuse up to the palisade tissue or down to the stomata
What is the function of stomata?
Small pores which allow gasses and water in or out by opening or closing
What is the function of guard cells?
Control the stomata
What is the function of waxy cuticle?
Reduces water loss through evaporation
Where can meristem tissue be found in a plant?
Growing tips of shoots and roots
Describe the cross section of a leaf?
The top layer is epidermal tissue with a waxy cuticle
The next layer is the palisade mesophyll tissue
Then there is the spongy mesophyll tissue
Finally there is another layer of epidermal tissue with stomata and guard cells
(See Figure 6)
How is the upper epidermis specialised for photosynthesis?
It is transparent so that light can pass though
How is the lower epidermis specialised for photosynthesis?
Contains stomata and guard cells
How is the stomata specialised for photosynthesis?
They have guard cells which
- allow them to open to take in reactants and let out waste products
- allow them to close to prevent water loss
How is the spongy mesophyll specialised for photosynthesis?
It has air spaces which means that gasses have shorter diffusion paths
How is the palisade mesophyll specialised for photosynthesis?
It contains many chloroplasts (where photosynthesis occurs)
Describe the phloem
Made of columns of elongated living cells with small pores to allow cell sap to flow through
Describe the xylem
Made of dead cells joined end to end with no end walls between them and a hole down the middle
What is the name of the material which strengthens the xylem?
Lignin
Describe the function of a xylem
Transport water and mineral ions from the roots to the leaves
Describe the function of a phloem
Transport food substances (many dissolved sugars) made in the leaves to the rest of the plant
What is translocation?
The process by which the phloem transports food substances around the plant
What is transpiration?
The movement of water from the roots, through the xylem and out through the leaves
What causes transpiration?
Evaporation and diffusion
Describe the process of transpiration
Water evaporates through the leaves
A shortage of water is created in the leaves
Water is drawn up through the rest of the plant
The roots have to draw more water
What four factors affect rate of transpiration?
Light Intensity
Temperature
Air Flow
Humidity
What does more humidity mean for transpiration?
Slower rate
What does greater light intensity mean for transpiration?
Faster rate
What does greater temperature mean for transpiration?
Faster rate
What does better air flow mean for transpiration?
Faster rate
What happens to guard cells when there is a lot of water in a cell?
They go turgid and plump
What happens to guard cells when there is little water in a cell?
They go flaccid
