20.5- Gene expression and cancer

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  • Created by: Megan2413
  • Created on: 27-03-18 15:37
What is cancer?
A group of diseases caused by damage to the genes that regulate mitosis and the cell cycle, leading to metastasis of a tumour
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What are the two types of tumour?
Benign and malignant
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Which tumour can grow to a large size?
Both
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Which tumour grows faster?
Malignant
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Which tumour contains cells with an abnormal darker appearance due to DNA abundance?
Malignant
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In which tumour are cells often specialised?
Benign
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Which thype of tumour is a primary tumour?
Benign
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What makes a benign tumour a primary one?
Cells produce adhesion molecules so they stick together and remain within the tissue from which they arose
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What type of tumour is a malignant tumour?
Secondary tumour
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Which tumour can carry out metastasis?
Malignant
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Which tumour is surrounded by a capsule of dense tissue to remain compact?
Benign
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Which tumour grows finger-like projections into surrounding tissue?
Malignant
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Which tumour is less-likely to be life-threatening?
Benign
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Which umour has systematic effects on the body?
Malignant
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What type of effect does a benign tumour have on the body?
Localised effects but can disrupt vital organ function
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Which tumour is usually removed by chemotherapy and surgey?
Malignant
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How are benign tumours usually removed?
By surgery
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Which tumour rarely reoccurs more after treatment?
Benign
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Can cancer cells derive from a single mutat cell?
Yes
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What are the two types of genes involved in cancer?
Tumour suppressor genes and oncogenes
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How does a primary tumour develop into a secondary tumour?
An enlarging tumour starts tp develop blood capillaries and lymphatic vessels. The tumour cells can squeeze into blood and lymphatic vessels and then adhere to blood vessel walls and squeeze through to form metastasis in another organ or lymph node
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What do proto-oncogenes do?
Stimulate a cell to divide
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How are proto-oncogenes activated?
When growth factors attach to a protein receptor on its cell-surface memebrane which then activates the gene
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What are oncogenes in relation to proto-oncogenes?
Most are mutations of proto-oncogenes
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Which two ways can an oncogene become permanently activated?
- receptor protein on cell-surface membrane can be permanently activated so cell division is carried out even in the absense of growth factors - Oncogene may code for a growth factor that is then produced in excess hence stimulates cell division
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Are most cancer-causing mutations in oncogenes acquired or inherited?
Acquired
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What are the three roles of a tumour suppressor gene?
To slow cell division, repair mistakes in DNA, cause apoptosis
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Explain how an inactive TP53 gene could lead to cancer
The TP53 gene codes for the p53 protein which is involved in apoptosis. If the gene isn't expressed and the p53 protein isn't produced, abnormal cells won't be destroyed and instead clone and form tumours, leading to cancer
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Oncogenes can cause cancer due to the activation of ________
Proto-oncogenes
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Tumour suppressor genes cause cancer when they are expressed/not expressed
Not expressed
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Hypermethylation can cause cancer when present in which gene?
Tumour suppressor genes
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What is hypermethylaton?
When there is increased methylation
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How does breast cancer occur from hypermethylation in tumour suppressor genes?
- hypermethylation occurs in the promotor region of tumour suppressor genes - transcription of the tumour suppressor gene is inhibited as promotor region is blocked - tumour suppressor gene is swicthed off - as it normally slows the rate of -->
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division a tumour forms
-->
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What type of methylation may occur in oncogenes leading to their activation and tumour formation?
Hypomethylation
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Card 2

Front

What are the two types of tumour?

Back

Benign and malignant

Card 3

Front

Which tumour can grow to a large size?

Back

Preview of the front of card 3

Card 4

Front

Which tumour grows faster?

Back

Preview of the front of card 4

Card 5

Front

Which tumour contains cells with an abnormal darker appearance due to DNA abundance?

Back

Preview of the front of card 5
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