Biology Mutations and Cancer (slide 5) Flashcards
Mutations are any change to our
DNA
Cancer is a
“disease of errors”
DNA (deoxyribonucleic acid) is the
genetic information
DNA is located in the
nucleus of cell
DNA is tightly coiled into
two strands known as chromosomes
DNA is made up of
deoxyribonucleotides repeated over and over
DNA is made up of:
Pentose sugar (deoxyribose)
Phosphate group
Nitrogenous bases (Adenine, Guanine, Thymine, Cytosine)
Nitrogenous bases
(Adenine, Guanine, Thymine, Cytosine)
The base pairings are always read in sequences of
three (codons)
Adenine (A) always pairs
with Thymine (T)
Guanine (G) always pairs with
Cytosine (C)
Strand 1: AAT-GCA-TGA-TAC
Strand 2: TTA-CGT-ACT-ATG
What is a “mutation”?
A mutation is a change in a cell’s DNA sequence
Why are mutations important?
Mutations can be beneficial and help organisms adapt to it’s environment
for evolution
Types of mutations:
Base substitution: an alteration of bases
Base insertion: adding a base
Base deletion: subtracting a base
Base substitution:
An alteration of bases
Base insertion:
adding a base
Base deletion:
subtracting a base
Base substitution
AAG-CTG-CAG becomes
AAG-CGG-CAG
Base insertion
AAG-CTG-CAG becomes
AAG-CAT-GCA-G
Base deletion
AAG-CTG-CAG becomes
AAG-CGC-AG
Cells are continually
replicating
If the DNA of a particular cell gets mutated, then this change can
also be seen
in any cells that arise from this particular cell
If any of the letters (codons) are changed,
then a new message is
being sent
Effects of mutations
Neutral
Deleterious
Lethal
Beneficial
There are checkpoints during
DNA replication and cell division
The cell’s nucleus and specialized proteins determine if the cell
should divide or remain in interphase
Cancer cells skip
checkpoints
Necrosis:
Death of cells due to external factors
Caused by toxins, radiation, infections,
and trauma
Apoptosis:
Programmed cell death (cell suicide)
When cells are no longer needed or if
the cell is copied incorrectly
What is “cancer”?
A group of cells with abnormal genetic
material that display three main properties
Uncontrolled growth
Invasion
Metastasis
Over
100 different types of cancer
Mutations are accelerated
in cancer cells
Mutations of cells can be accelerated by many factors
Environment: sunlight
Carcinogens: chemicals, smoking
What are “tumours”?
An abnormal growth of cells
Not all tumours are cancerous
Benign tumours:
Well defined borders
Do not metastasize
Not cancerous
Malignant tumours:
No defined borders
Metastasize
Cancerous
