Chapter 6 – Cancer
Review
Carbon dioxide functions as a greenhouse gas
by:
A. Interfering with water’s ability to absorb heat
B. Increasing the random molecular motions of oxygen
C. Allowing radiation from the sun to reach Earth and
absorbing the reradiated heat
D. Splitting into carbon and oxygen and increasing the
rate of cellular respiration
Review
Stomata on a plant’s surface:
A.
B.
C.
D.
Prevent oxygen from escaping
Produce water as a result of photosynthesis
Cannot be regulated by the plant
Are found in stacks called thylakoids
The Cell & Cancer
• Cancer is a disease caused by cells that
replicate uncontrollably
• Cell go through cell division more often than
normal
– Cell division – process where a cell makes a copy of
itself
Malignant vs. Benign Tumor
• Tumor: unregulated cell division that forms a
pileup of cells
• Benign tumor: abnormal mass of cells that stay in
one place and do not affect surrounding structures
• Malignant tumor: invade and damage surrounding
tissue
– Metastasis – spread of cancer cells to form a new tumor
in a different location
Cancer Risk Factors
Normal Functions of Cell Division
• Growth
• Repair
The Chromosome
• Genes are portions of
DNA that code for
proteins (determine
traits and body
functions)
• DNA is wrapped
around proteins called
histones
• Organized DNA and
proteins are called
chromosomes
http://www.dnalc.org/resources/3d/07-howdna-is-packaged-basic.html
DNA Replication
• In order for the cell to
split in two, the DNA
must duplicate
• The synthesis of a
DNA copy is called
DNA replication
• DNA Replication 1. DNA unwinds
2. Free nucleotides
are added to both
strands by DNA
polymerase
The Cell Cycle - Interphase
• Interphase: in
between phase
– G1 – organelles/cell
parts duplicate
– S – chromosomes
duplicate (DNA
Replication)
– G2 – Cell checks for
any errors during
duplication
The Cell Cycle - Mitosis
• Mitosis: chromosome division
–
–
–
–
Prophase - X shape formation or packaging
Metaphase – alignment of chromosomes in the middle
Anaphase – chromosomes move apart
Telophase – two nuclei form
The Cell Cycle - Cytokinesis
• Cytokinesis: cells
divide
– Plant Cells – requires
formation of a cell
plate and a new cell
wall to be built
– Animal Cells –
requires a contracting
microfilament ring
Regulation of the Cell Cycle
Genes & Environment Effect on Cancer
• Cause of Cancer – mutations (change in
normal DNA) in cell cycle genes
• Types of genes that can get mutated– Proto-oncogenes: control cell division
– Tumor Suppressors: stop cell division if there are
problems
• Types of causes of attaining mutations– Environment: UV rays & toxic chemicals
– Genes: inherited
Cancer Detection & Treatment
• Detection
– Biopsy: surgical removal of cells, tissue, or fluid
that will be analyzed to determine whether they
are cancerous
• Treatment
– Chemotherapy: chemicals are injected into the
bloodstream
– Radiation therapy: uses high-energy particles to
injure or destroy cells by damaging their DNA
Meiosis - Purpose
• Meiosis creates reproductive cells (egg &
sperm cells)
– Four cells from one original cell
• These cells are called gametes
• Gametes contain half of an organism’s genetic
information (the other half comes from the
other parent); this is called a haploid number
of chromosomes
Meiosis - Process
Meiosis – Genetic Diversity
• Crossing over:
exchange of
portions of
chromosomes
– Chromosome’s
genetic information
is exchanged
making each
gamete genetically
different
Meiosis – Genetic Diversity
• Random
Alignment:
random
arrangement of
chromosomes
– Chromosome’s
movement to
random gametes
makes genes
unpredictable