Flashcards in Topic 2- Organisation Deck (124):
What type of cells form tissues?
When does differentiation occur
During the development of a multi cellular organism
What is the purpose of glands in the digestive system?
It is found in the pancreas and salivary glands, produces digestive juices
Definition of organ
A group of tissues that work together to perform a certain function
Definition of enzymes
Definition of catalyst
A substance which increases the speed of a reaction without being changed or used up
What are enzymes made of?
Proteins, and all proteins are made of chains of amino acids
What does every enzyme have?
An active site with a unique shape that fits onto the substance involved in a reaction
Name of the diagram that shows enzyme action
"Lock and key" model
How is the lock and key different to the reality and what is it called
In reality, the active site changes shape a little as the substrate binds to get a tighter fit and it is called induced fit
2 things that affect enzymes
Temperature and pH
What happens to an enzyme when the temperature is too high?
Some of the bonds holding the enzyme together break, and this changes the shape of the active site, so the substance won't fit. It is said to be DENATURED.
What is the use of pepsin enzyme in the stomach
It is used to break down proteins in the stomach
Optimum pH of pepsin?
What does the enzyme amylase catalyse?
It catalyses the breakdown of starch to maltose.
What will the colour of iodine solution be, when starch is present?
Describe the practical for how pH affects amylase activity
A drop of iodine solution in each spotting tile. Heat water in beaker until 35°c. In a test tube, add 1 cm^3 of buffer solution with pH 5 and 1 cm^3 of amylase solution and wait 5 mins. Then add 5 cm^3 of starch solution,mix and start clock. Every 30 secs, add a drop, when the iodine solution remains browny orange, starch is no longer present. Repeat with different pH buffer solutions to see how pH affects time.
What is the meaning of rate?
Rate is a measure of how much something changes over time.
Formula to work out the rate
Rate = 1000
Why do starch, proteins and fats have to be broken down?
Because they are big molecules. They are too big to pass through walls of the digestive system, smaller molecules are easier to absorb into bloodstream.
Protease breaks down _ _ _ _ _ _ _ _ into _ _ _ _ _ _ _ _ _ _ _
Proteins into amino acids
All three enzymes are found in?
Small intestines and pancreas
What is another name for protease in the stomach?
What is starch broken down i)by ii)into?
i) amylase ii) maltose
An example of carbohydrase?
Where are lipases found?
In the pancreas and small intestines.
Where is amylase found where the other enzymes aren't?
Example of other sugars apart from maltose
What are lipids?
Fats and oils
Where is bile produced?
In the liver
Where is bile released into
What does bile do in the small intestines
HCl in the stomach is too acidic. Bile is alkaline. Enzymes in small intestines work best in akaline conditions.
What does bile do?
It emulsifiers fat, meaning it breaks down the fat into tiny droplets, increasing the surface area of fat for enzymes to work on, making digestion faster.
What is the purpose of HCl in the stomach?
To kill bacteria and to give right pH for protease enzyme to work
4 things you must do to prepare a food sample.
Break up food using pestle and mortar
Transfer food to beaker and add water
Stir mixture with glass rod to dissolve food
Filter solution using filter paper to get rid of solid bits of food.
What is the name of the test for sugar
Describe the test for sugar
Prepare food sample and transfer 5 cm^3 to test tube and set water bath to 75°c. Add Benedict's solution (10 drops) to test tube and leave in bath for 5 mins. If reducing sugar is present, the colour will change from blue to green, yellow or brick red.
Test for starch
Make food sample and transfer 5 cm^3 to test tube. Add iodine solution and shake to mix. Solution will change from brown orange to black or blue black
Test for proteins
Prepare sample and transfer 2cm^3 to test tube. Add 2 cm^3 of Buiret solution to sample and shake to mix. If protein present, colour will change from blue to pink or purple.
Test for lipids
Prepare sample and transfer 5 cm^3 to test tube. Add 3 drops of Sudan III stain solution and shake to mix. If lipids present, it will separate to top layer bright red.
What is the thorax?
The top part of your body
How is the top part of your body separated from the lower part?
What are the lungs surrounded by?
Where does gas exchange take place?
Small bags at the end of bronchioles called alveoli
Diffusion in alveoli
Oxygen diffuses out of the alveoli into blood and CO^2 diffuses out of blood into alveoli.
Red blood cells action after gas exchange
Red blood cells release oxygen and diffuses into body cells and body cells release CO^2 which diffuses into blood and carried back to lungs.
Formula to calculate breathing rate.
Breaths per minute= number of breathes
Number of minutes
Describe the double circulatory system
The right side of the heart pumps deoxygenated blood to the lungs and returns with oxygen to the heart.
The left side of the heart pumps oxygenated blood to the rest of the body and returns with deoxygenated blood.
What is the walls of the heart mostly made of?
What do valves in the heart do?
They make sure blood flows in the right direction, preventing it from flowing backwards.
How many chamber are there in the heart and what are they called?
Right atrium, right ventricle, left atrium, left ventricle
What is the equivalent of the pulmonary vein called on the right side?
What do the atria do when blood flows into them?
They contract, pushing blood into ventricles.
What is the equivalent of the pulmonary artery called on the left side?
What do the ventricles do when blood flows in?
They contract pushing blood through the pulmonary artery and aorta, out of the heart.
The blood flows through _ _ _ _ _ _ _ _ and returns through _ _ _ _ _ .
Flows through arteries and returns through veins
What are the coronary arteries?
They branch off the aorta supply the heart with its own oxygenated blood supply
What is your heart rate controlled by?
A group of cells in the right atrium wall
What do the group of "pacemaker" cells do?
They produce a small electrical impulse which spreads to surrounding muscle cells causing them to contract.
What is done if the patient has irregular heartbeat?
An artificial pacemaker is implanted under the skin and has a wire going to heart.
What do veins do?
Carry blood to the heart
What do capillaries do?
Involved in material exchanges at tissues
What do arteries do?
Carry blood away from heart
2 features of artery walls
Strong and elastic
What is the name of the hole in the middle of an artery
How are the arteries strong and elastic?
They contain a thick layer of muscle for strength and have elastic fibres to allow them to stretch.
A features of arteries
They carry blood under high pressure
How are the walls of capillaries adapted for diffusion
They have permeable walls and it is also one cell thick, which decreases the diffusion distance
How are arteries, capillaries and veins connected?
Arteries branch into capillaries and capillaries eventually join up to form veins
Is the blood pressure high or low in the veins?
Low, so the walls don't need to be as thick as arteries
How do the veins keep the blood flowing in one direction
They have valves
Do veins have bigger or smaller lumen than arteries?
Bigger because the walls are thinner
Formula to calculate rate of blood flow?
Rate of blood flow= volume of blood flow
Number of minutes
What is the shape of red blood cells?
What is the name given to haemoglobin binded with oxygen in the lungs?
What are red blood cells like in people who live in high altitude?
There is less oxygen in the air so they produce more red blood cells
What do white blood cells have that red blood cells don't?
What are platelets?
They are fragments of cells, which have no nucleus.
How do platelets help?
They help blood clot at a wound to stop blood loss and microbes entering.
Name 8 things that plasma carries
Red and white blood cells and platelets.
Nutrients (glucose and amino acids)
CO^2 - organs to lungs
Urea- liver to kidneys
What is coronary heart disease?
It is when coronary arteries get blocked by layer fatty material building up. This causes passage to become narrow, so blood flow is restricted and lack of oxygen to heart muscle, resulting in a heart attack
How do stents work?
They keep the passages open, making sure blood passes to heart muscles, by pushing wall out.
2 advantages of stents
Thy are effective, and recovery time is quick
2 disadvantages of stents
Risk of complications and risk of infection
Definition of thrombosis
Risk of patients developing a blood clot near stent
What could cause coronary heart disease
Too much bad cholesterol which can cause fatty deposits
What are statins
Drugs that reduce amount of bad cholesterol present in blood.
3 advantages of statins
Reduce risks of strokes, coronary heart disease and heart attacks
Increase amount of good cholesterol, which can remove bad cholesterol
May prevent other diseases
3 disadvantages of statins
Long term drugs, must be taken regularly, could forget
Negative side effects (headaches, kidney failure, memory loss)
Isn't instant, takes time for effect
What are artificial hearts?
Mechanical devices that pump blood for a person whose own heart has failed.
Are artificial hearts permanent or temporary?
Most cases, temporary until donor heart can be found or to allow heart to rest or heal, but some cases, permanent
Advantage of artificial hearts
Less likely to be rejected. Made from metals or plastics, so not recognised as "foreign"
Disadvantages of artificial hearts
Don't work as well as natural ones, electrical motor could fail
Blood doesn't flow as smoothly could cause clots and strokes.
Patient has to take drugs to thin blood, could cause problems when hurt
3 ways that could cause heart valves to be damaged
Heart attacks, infection or old age.
Describe how a faulty heart valve could lead to poor blood circulation
Could stiffen, so it won't open properly
Could become leaky and blood flow could be both directions
How can valve damage be fixed?
Valve replacement from humans or mammals (cows or pigs) which are biological valves or man made which are mechanical valves
What is artificial blood?
It is a blood substitute and it may give the patient enough time to produce new blood cells.
Definition of health
Health is a state of physical and mental wellbeing.
4 things that cause communicable diseases?
Bacteria, virus, protists and fungi
3 factors that affect health
Life situations (access to medicine or healthy food)
What are risk factors
Things that are linked to an increase in the likelihood that a person will develop a certain disease during their lifetime
Types of risk factors
A person's lifestyle
Presence of a certain substance in the environment
Substance in your body
Some risk factors that directly cause a disease
Smoking- cardiovascular disease, lung disease and lung cancer
Obesity- type 2 diabetes
Smoking when pregnant- health problems for unborn baby
Cancer- exposure to certain substances or radiation
Things that cause cancer are known as what?
3 things to do with the financial side of non communicable diseases
Cost of NHS research and treatment is huge
Families having to move for treatment is also costly
If someone dies, reduction in income and affects country's economy
What results to the formation of tumours?
Uncontrolled growth and division of cells and results in tumour
Definition of tumour
A mass of cells
Definition of benign
Tumour grows until there's no room, and it stays in one place. Isn't normally dangerous and isn't cancerous
Definition of malignant
Tumour grows and spreads. Cells can break off and travel to other parts of the body. Can form secondary tumours. Dangerous and can be fatal, cancers
5 risk factors for cancer
UV exposure (sun beds, hot climate)
Where does most photosynthesis happen in a plant?
Palisade mesophyll tissue
Where and why are there air spaces in a leaf?
In the spongy mesophyll tissue for gases to diffuse in and out of cells
What is the meristem?
It is found at the growing tips of shoots and roots and is able to change into lots of different types of plant cells.
How is the lower epidermis adapted for gas exchange?
Full of little holes called stomata which let CO^2 diffuse directly into leaf
What does the phloem transport?
Food substances made in leaves to rest of plants for use or storage.
What are phloem tubes like?
Made of columns of living cells with small pores at the ends to allow cell sap.
Definition of translocation
Transportation of food substances from leaves to the rest of plant
What are xylem tubes like?
Made of dead cells joined end to end with no walls between them.
What do xylem tubes transport?
Water and mineral ions from roots to stem and leaves.
Definition of transpiration stream
Movement of water from roots through xylem and out of the leaf.
Definition of transpiration
Evaporation and diffusion of water from a plant's surface (mostly at leaves)
4 main things that affect that transpiration rate
Light intensity- stomata closes as it darkens. Stomata closed means less water escape
Temperature- the warmer,the faster. Warm,more energy, diffuse out.
Air flow- good airflow means water vapour is swept away main into the lower concentration outside, so diffusion rate increases
Humidity- drier the air, faster transpiration. Air is humid means lots water already, not much difference
Why are there normally more stomata on the underside of leaves than the top?
The lower surface is shaded and cooler, so less water is lost