B2 Flashcards
What are the smallest level of the organisation ?
cell , tissue , organ , organ system , organism
What is the definition of a cell?
- basic building block of all organisms
What is the definition of a tissue?
- a group of cells with a similar structure and function
What is the definition of an organ?
- a group of tissues working to complete a particular function
What is the definition of an organ system?
- a group of organs which work together to form an organism
What happens in the digestive system?
- in the digestive system enzymes break down large, insoluble, molecules into smaller soluble ones
- which can be absorbed into the bloodstream
What are the parts of the digestive system?
- mouth
- salivary gland
- oesophagus
- liver
- stomach
- pancreas
- large intestine
- small intestine
- rectum
- anus
What is the function of the salivary glands?
- produce the amylase enzyme to start digestion
What is the function of the stomach?
- produce the protease enzyme to digest food
What is the function of the liver?
- produces bile to neutralise stomach acid and emulsify fats
What is the function of the pancreas?
- produces digestive enzymes
What is the function of the small intestine?
- where digested, small soluble molecules are absorbed into bloodstream
What is the function of the large intestine?
- water from undigested food is absorbed
What is an enzyme?
- it is a protein molecule which can speed up reactions
What is a catalyst?
- is a substance which increases the speed of a reaction without being changed or used up in the reaction
Describe what is meant by lock and key theory
- the substrate fits into the active site of the enzyme
- the enzyme then breaks the substrate into the products which are released from the active site
- the enzyme is not used up in the reaction and will be able to break down another substrate molecule
Why do we say that enzymes are specific?
- enzymes are specific because the active site is a particular shape and only one type of substrate can fit
What do we mean when we say an enzyme has denatured?
- if an enzyme is in the wrong conditions it can denature
- this is where the active site changes shape so the substrate won’t fit anymore
What will happen to the rate of reaction when the temperature increases?
- if the increase in temperature makes the rate of reaction increases up to the optimum temperature
- after this, the active site of the enzyme starts to change shape , the substrate won’t fit and the enzyme is denatured
What will happen to the rate of reaction when the pH is too low or too high?
- if the pH is too low or too high the active site of the enzyme starts to change shape, the substrate won’t fit and the enzyme is denatured
- the pH the enzyme works best at is called the optimum pH
What does carbohydrase (an example) break down and where its made in?
- example would be amylase
- it breaks into starch
- into sugar (glucose)
- its made in the : salivary glands , pancreas & small intestine (SI)
What does protease (an example) break down and where its made in?
- example would be pepsin
- it breaks into proteins
- into amino acids
- its made in the : stomach , pancreas & SI
What does lipase break down and where its made in?
- it breaks into lipids (fats)
- into (1) glycerol & (3) fatty acids
- its made in the : pancreas & SI
Which molecule does bile help to digest?
- fats (lipids)
What is a globule?
- a large blob of fat
What does bile do to the globules and why does this help digestion?
- it emulsifies the fat (breaks it into small droplets)
- which increases the surface area so the enzymes can work at a faster rate
Compare the pH of the food being digested before and after the bile is added. Explain why this happens
- the stomach is acidic (pH 1)
- The bile is alkali so it neutralises the stomach acid
Use your knowledge of the digestive system to describe the journey of a cheese sandwich from mouth to anus
- mouth = teeth grind the food into smaller chunks
- salivary glands = produce amylase that helps breakdown starch
- oesophagus = connects to the stomach
- stomach = acid to help kill any pathogens. Pepsin (protease) to breakdown proteins
- small intestine = mixes with amylase, protease, lipase
- pancreas = produces enzymes to help breakdown foods
- liver = produces bile to neutralise stomach acid and breakdown fats
- small intestine = nutrients absorbed through villi
(food does not pass through pancreas and liver) - large intestine = water absorption
- rectum & anus = faeces stored and excreted
What is meant by ‘health’?
- the state of physical and mental well-being
What is meant by a ‘communicable disease’?
- a disease which can be spread
What causes communicable diseases?
- pathogens: bacteria, viruses, fungi and parasites
What is meant by a ‘non-communicable disease’?
- a disease which cannot spread
Give an example of a non-communicable disease?
- coronary heart disease
Write a paragraph where you:
1) Explain what is meant by a risk factor
2) Describe a range of risk factors and link them to specific diseases
3) Discuss the cost implications of poor health
- risk factor are anything that increases a chance of developing a disease these can be caused by a certain lifestyle an individual is living
- there’s a range of risk factors such as obesity (due to a poor diet , lack of exercise and an excess amount of food consumption). this can have cause some problems with their blood sugar level as possible they might not be able to regulate it properly. if this carries on it can lead to type 2 diabetes
- or another could be an excess amount of alcohol consumption which can cause diseases such as liver cirrhosis. As scar tissue has been formed in the liver this consequently stops the liver from removing toxins.
- another risk factor may also be smoking as fatty plaque will build up in the coronary arteries and can later on cause lung cancer
- in conclusion the cost implications are bad because poor health means people can’t work
What is a benign tumor?
- a tumour which does not spread and is not normally dangerous
What is a malignant tumour?
- tumours which spread to other parts of the body and form secondary tumours. More dangerous
How do cancers spread?
- some of the tumour breaks off and travels in the bloodstream to another part of the body
Name 5 risk-factors for cancer (be clear if the risk factor causes a particular type of cancer)
- smoking
- obesity
- viral infections
- UV exposure (linked to skin cancer)
- genetic inheritance
Why have cancer survival rates improved?
- better treatments
- earlier diagnosis
- more screening
- public awareness of risk factors
Why have cancer survival rates improved?
- better treatments
- earlier diagnosis
- more screening
- public awareness of risk factors
What is the function of the coronary artery?
- to supply the heart muscle with oxygenated blood
Where is it found?
- on the outside of the heart
What happens in coronary heart disease?
- layers of fatty deposits build up inside the coronary artery
- which makes it narrow
What effect can this have on the heart muscle?
- less blood gets to the heart, so less oxygen
- this can cause a heart attack
What are the 4 treatment used for coronary heart disease?
- stents
- statins
- artificial hearts
- valve replacement
How does stents work?
- used to open up and keep open coronary arteries
What are the advantages + disadvantages of stents?
ADVANTAGES:
- works instantly
- effective for a long time
- recovery time is quick
DISADVANTAGES:
- risk of heart attack after the operation
- risk of infection after surgery
- blood clots can form near stent
How does statins work?
- used to reduce blood cholesterol levels less fatty material deposited
What are the advantages + disadvantages of statins?
ADVANTAGES:
- reduce risk of stroke, coronary heart disease, heart attacks and other diseases
DISADVANTAGES:
- may forget to take them
- unwanted side effects (headaches)
- takes time to work
How does artificial heart work?
- keep a person alive until donor heart is available or while heart recovers
What are the advantages + disadvantages of artificial hearts?
ADVANTAGES:
- made from metal or plastic, less likely to be rejected
DISADVANTAGES:
- bleeding during surgery
- may lead to blood clots or strokes
- drugs needed to thin blood
How does valve replacement work?
- replacing damaged valves with biological (from animals)
OR
- mechanical (man-made) valves
What are the advantages + disadvantages of valve replacement?
ADVANTAGES:
- less risky than heart transplant
DISADVANTAGES:
- blood clots
- possible rejection
