Anatomy & Physiology: Cancer and Cell Cycle Learning Targets

Contains learning targets from Cancer and Cell Cycle (mitosis, mutations, cancer) for the final

Top risk factor for cancer

Age

Why is age the top risk for cancer?

More time for genetic mutations to develop

How cancer develops

Mutations in DNA cause cells to grow out of control

Tumor suppressor genes

* Slow down cell division
* Repair DNA mistakes
* Apoptosis (cell suicide)

Proto-oncogenes

Control the speed of the cell cycle

Benign Tumor

Non-cancerous tumor

Malignant Tumor

Cancerous tumor

Types of Mutations

* Substitution
* Deletion
* Insertion

Substitution (mutation)

* Point mutations
* one nucleotide is replaced by a different nucleotide
* causes incorrect amino acid to be formed, not the worst unless stop codon is formed early

Original: TAC GAG CAT CAC TGT ATC

Mutation: TAC GA**T** CAT CAC TGT ATC

Substitution

Deletion (mutation)

* Frameshift mutation
* one(or more) nucleotide is deleted all together
* causes incorrect amino acids to be formed and last codon doesn’t have 3 bases, not good

Original: TAC GAG CAT CAC TGT ATC

Mutation: TAC GA**C** ATC ACT GTA TC

Deletion

Insertion (mutation)

* Frameshift mutation
* the addition of one or more nucleotides into a segment of DNA
* causes incorrect amino acids to be formed because there is a extra base added causing the last codon to not have 3 bases , not good

Original: TAC GAG CAT CAC TGT ATC

Mutation: TAC GAG CAT **T**CA CTG TAT C

Insertion

Point Mutations (3)

* Nonsense
* Missense
* Silent

Nonsense (point mutation)

occurs when one nucleotide is substituted and this leads to the formation of a **stop codon** instead of a codon that codes for an amino acid (substitution)

Original: Met-Leu-Val-Val-Thr-STOP

Mutation: Met-Leu-**STOP**- - -

Nonsense

Missense (point mutation)

occurs when one nucleotide is substituted and the codon produces a **different amino acid** in the sequence of amino acids (Frameshift)

Original: Met-Leu-Val-Val-Thr-STOP

Mutation: Met-Leu-**Pro**-Val-Thr-STOP

Missense

Silent (point mutation)

a nucleotide is substituted but the **same amino acid** is produced anyway

Original: Met-Leu-Val-Val-Thr-STOP

Mutation: Met-Leu-Val-Val-Thr-STOP

Silent

Carcinogen

Anything that can cause cancer

ex. tobacco, alcohol, sunlight

Amount of individuals who will get cancer

22\.92%

Inherited Mutations

* Gene defects that are passed from parent → child
* mutation exists in all cells

Acquired Mutations

DNA changes that are acquired during a person’s life

Prophase (1)

* Longest phase (50%-60% spent there)
* Chromosomes become visible
* Centrioles separate to opposite sides of cell (form spindles)
* Nucleolus disappears and nuclear envelope breaks down

Identify the phase of mitosis

Prophase

Metaphase (2)

chromosomes line up in center of cell

Identify the phase of mitosis

Metaphase

Anaphase (3)

sister chromatids split up apart into individual chromosomes and move apart

Identify the phase of mitosis

Anaphase

Telophase (4)

* Chromosomes turn back into chromatin
* Centrioles go back into pairs (spindles disappear)
* Nucleolus appears and nuclear envelope forms again
* Final step

Identify the phase of mitosis

Telophase

Cytokinesis

* NOT part of mitosis
* Cell division
* Cell plate (line forms and makes 2)
* Cleavage furrow pinches them apart

Interphase

* Cell is performing everyday tasks (metabolic)
* 90% spent in this stage
* G1, S, G2

G1 (interphase)

Cell growth

S (interphase)

DNA replication (make/copy chromosomes)

G2 (interphase)

Prepare for mitosis