B7- non-communicable diseases 🚬🚭

Question 1

How is a tumour produced ? [3]

Answer 1

• cell division by mitosis occurs all over the body, especially during growth and during repair-[e.g- after an injury]
• mitosis is extremely tightly controlled, since genes in the nucleus tell cells when to divide and when to stop dividing.
• ; sometimes changes take place in these genes and that leads to the uncontrolled growth, and mitosis- this produces a tumour.

Question 2

What are the two types of tumours ?

Answer 2

• the two types of tumours, are benign and malignant tumours.

Question 3

What are benign tumours ?

Answer 3

• benign tumours, are growths of abnormal cells which are found in one area.
• benign tumours are usually contained within a membrane, and benign tumours don’t invade other parts of the body- they stay in one place

Question 4

What are malignant tumours ?

Answer 4

• malignant tumors, are tumors which invade neighbouring tissues, and move into the bloodstream.
• once malignant cells are in the bloodstream, the malignant cells can spread to different parts of the body, and form new tumours. [known as secondary tumours]
• they are classified as a cancer.

Question 5

What are the difference between benign tumours 🆚 malignant tumours? [6]

Answer 5

• benign tumours, are growths of abnormal cells which are found in one area; with malignant tumours, malignant cells invade neighbouring tissues.
• malignant cells are made of cancerous cells; benign tumours aren’t.
• malignant - malignant cells can also move into the bloodstream; benign tumours don’t.

Question 6

What are the similarities between benign tumours 🆚 malignant tumours? [4]

Answer 6

• benign and malignant tumours are made up of abnormal cells and are a result of changes in the genes.
• both tumours can form a lump of cells, and are a result of uncontrolled cell division.

Question 7

What are risk factors for developing cancer ? [4]

Answer 7

• some cancers are genetic, and we inherit an increased risk of those cancers from our parents- [e.g- certain types of breast and prostate cancer]
• smoking is a risk factor for lung cancer
• and exposure to ultraviolet lights [e.g- sunbathing], is a risk factor for skin cancer.
• alcohol is a risk factor for mouth, and throat cancer.

Question 8

How are certain cancers linked to substances, in our environment ? [3]

Answer 8

• certain cancers linked to substances, in our environment, for example…
• radon, is a radioactive gas which increases your risk of developing lung cancer.
• This is because, radon releasing ionising radiation which damages the DNA in our cells.
• Therefore, this can cause our cells to undergo uncontrolled cell division- leading to cancer.

Question 9

Explain how benign and malignant tumours can be life-threatening.

Answer 9

• benign tumours can be life-threatening, if they press against vital organs- [e.g- your brain]
• [malignant] cancer cells can be life-threatning, since they take up the needed space and nutrients that the healthy organs would use.
• And as a result, the healthy organs can no longer function

Question 10

How can a lack of control in the cell cycle to tumour formation ?

Answer 10

• a lack of control in the cell cycle to tumour formation,
• because defects in the genes that control the mitotic surveillance mechanism [needed for chromosome sorting], can lead to abnormalities in the number of chromosomes.
• meaning this can lead to the formation of a cancer, when normal cells, are ‘transformed’ into cancerous cells.

Question 11

What is the mitotic surveillance mechanism ?

Answer 11

• the mitotic surveillance mechanism, is a pathway preventing the growth of human cells, which will have an increased chance of making errors in mitosis.

Question 12

Compared to communicable, what are most non-communicable diseases caused by ?

Answer 12

• unlike how communicable diseases are caused by the spreading of pathogens, non-communicable diseases are caused by risk factors.

Question 13

What is a key fact about correlation ?

Answer 13

• correlation doesn’t prove cause.
• For example, a graph of the risk of developing lung cancer, with the number of cigarettes smoked per day, doesn’t prove that cigarette smoking causes lung cancer.
• it only suggests that smoking and lung cancer might be linked.

Question 14

What is a causal mechanism ?

Answer 14

• a casual mechanism, is seeing if there is any scientific explanation why something happens.
• it simply means, there’s a link between two factors.

Question 15

What is the casual mechanism for smoking and lung cancer ?

Answer 15

• as scientists began to look at how cigarette smoking could cause cancer…
• they discovered that cigarette smoke, contains chemicals which damage DNA, increasing the risk of cancer [known as carcinogens]

Question 16

What are carcinogens ?

Answer 16

• carcinogens, are chemicals which damage DNA and increase the risk of cancer.

Question 17

What’s the problem with sampling ?

Answer 17

• with sampling, we ideally want to look at every person in the population; it’s not possible to sample every single person.
• so instead, scientists will sample a group of people and then try to draw conclusions about the whole population.
• ; sampling isn’t representative of the whole country, since it can be bias- meaning we can’t use the results, to draw conclusions about the whole population.

Question 18

How could we investigate, how studying the patterns of disease, determines risk factors ?

Answer 18

• if we want to investigate how studying the patterns of disease, to determine risk factors, this can pose a problem- sampling.

Question 19

How can we avoid bias in sampling ?

Answer 19

• to avoid bias, we need to take as large of a sample as possible, and it it must be as random as possible.
• since we can’t draw conclusions from a small or non-random sample.

Question 21

What is a risk factor ?

Answer 21

• a risk factor, is anything that increases a [person’s] chance of developing a disease

Question 21

What is a correlation ?

Answer 21

• a correlation, is a relationship between two sets of data- it shows a connection factor and an outcome.

Question 22

What is the difference between a risk factor 🆚 a correlation 🆚 a casual mechanism ? [4]

Answer 22

• a risk factor, is anything that increases a [person’s] chance of developing a disease
• a correlation, is a relationship between two sets of data- it shows a connection factor and an outcome.
• a casual mechanism, is seeing if there is any scientific explanation why something happens. [simply means a link bewteen two factors]

Question 23

Explain how the causal link between smoking and lung cancer was identified.

Answer 23

• in the 1930s, rates of lung cancer began to sharply increase; scientists couldn’t explain this.
• since it would be unethical to carry out experiments on humans, to try to work out what causes lung cancer..
• scientists began to look very closely at people’s lifestyle habitats- in an to attempt, to link any of these lifestyle habitats to lung cancer.

Question 24

Explain in detail how the causal link between smoking and lung cancer was identified. [4]

Answer 24

• as scientists began to look very closely at people’s lifestyle habitats…
• they noticed, that lung cancer is much more common among cigarette smokers, than in non-smokers.
• They then looked at how many cigarettes people smoked each day, and then looked at how of these many people developed lung cancer- they were looking to see, if there was a correlation between lung cancer and smoking.

Question 25

How can scientists determine whether there is a correlation ?

Answer 25

• scientists can determine whether there is a correlation, by using a scatter graph.
• from the scatter graph, it showed that as the number of cigarettes smoked per day increases, so did the risk of developing lung cancer.
• after finding a positive correlation, they then plotted a graph of the number of years a person smoked, versus the risk of developing lung cancer- it showed a positive correlation again.

Question 26

When scientists attempted to find a link between smoking and lung cancer, what were the two graphs ?

Answer 26

• from the first scatter graph, it showed that as the number of cigarettes smoked per day increases, so did the risk of developing lung cancer.
• after finding a positive correlation, they then plotted a second graph of the number of years a person smoked, versus the risk of developing lung cancer- it showed a positive correlation again.

Question 27

What is epidemiology ? [1]

Answer 27

• epidemiology, is studying the pattern of diseases, to determine risk factors.