Cells are the basic unit of life, and all living things are made of cells. Cells contain organelles that perform specific functions, and eukaryotic cells contain a nucleus. DNA located in the nucleus contains the genetic instructions that are used to direct cell functions and create proteins through the processes of transcription and translation of DNA to mRNA to proteins.

2. • All living things are
made up of cell
• All cells come from
other cells
• Prokaryotes: organisms whose cells lack a nucleus
(single-celled organism—EX: bacteria)
• Eukaryote: organisms whose cells contain a nucleus
(multi-celled organism—EX: animal cells/plant cells)
• Homeostasis: the stable, internal state of an
organism in which cells are kept alive despite
changing external conditions (EX: humans maintain
the internal temperature of 98.6°F despite changing
external temperatures around them)

3. Organelles: structures within cells that perform a specific function
Animal and Plant Cells
• Nucleus: command center of the cell
and controls it’s activities—houses DNA
• Mitochondria: breaks down food
molecules (like the sugar glucose) to
release the energy stored
• Ribosomes: where proteins are made
Plant Cells
• Chloroplast: uses the energy in sunlight to
make glucose (a sugar that stores energy)

4. • Found in the cell of all organisms
• Contains the genetic information that
controls what a cell can do and what
types of molecules it can make
• Made of of million of units called
Nucleotides, which are arranged into
two strands (double-helix) with the
sugar/phosphate group making up
the ladder and the nitrogen bases
making up the rungs
• The four nitrogen bases in DNA are:
• Guanine (G) and Cytosine (C)
• Adenine (A) and Thymine (T)
• The bases are complimentary:
• C pairs with G and A pairs with T

5. Replication: The process of cell
division—results in two identical
copies of a DNA molecule
• Enzymes unwind two strands of
DNA and pairs new
complimentary nitrogen bases
together to form a new strand
• Each strand contains the
information needed to make the
new strand
• The cell now has a complete set
of the organism’s genetic
information and can replicate
again
• This is how all new cells are
created

6. it has uracil (U). The process of copying the genetic in
DNA into mRNA is called transcription.
• A cell can make a copy of part of it’s genetic Transcription of a DNA Strand
code that tells it how to make a protein DNA strand: T A C T T T A G T A A C
• This copy is called a mRNA (Messenger
RNA)—carries that information from the DNA mRNA: A U G A A A U C A U U G
to other parts of the cell
• Proteins: the “machines”O the cell that from DNA to mRNA. What happens
of we’ve gone
.K.,
perform a specific task—Ex: red blood
A molecule of mRNA contains information on how to
cells contain the protein hemoglobin
protein. Proteins can be thought of as the machines of
• The four nitrogen bases for RNA are
protein performs some specific task. For example, hem
• Guanine (G) and Cytosine (C)in red blood cells that helps carry oxygen from
protein
• Adenine (A) and Uracil (U) tissues.
body
• Transcription: The process of copying the
The information in mRNA is organized into three-lette
genetic information in DNA to mRNA
• tRNA (Transfer RNA): reads the instructions are like the words of the RNA message
codons. Codons
from mRNA and strings amino acids together
in the correct order to form a protein chain
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• Translation: The process in which tRNA
produces a protein from mRNA

7. Codons: three-
letter blocks of
nitrogen bases
of the mRNA
that serve as the
“words” of the
message about
what protein the
cell will make
• Each codon
codes for a
specific
amino acid in
the protein
chain

8. hemoglobin is a protein that carries oxygen in red blood cells.) This
mutation causes the mRNA to change from GAA to GUA. The amino
acid valine would be added to the protein instead of glutamic acid. This
change results in an abnormal form of hemoglobin that causes red
• A mistake or change in the DNA sequence—a
blood cells to have a sickle, or crescent, shape. The sickle-shaped cells
cannot flow well through narrow blood vessels, resulting in a variety ofchange
in DNA can lead
to a change in mRNA that can lead to a change in the
health problems. protein created
• types ofcause one orNOT nucleotideshaveaddedeffect on
OtherMutations DO affect more than one codon. For instance, a an organism HOWEVER
mutation can
mutations
more
usually to be an to or deleted
from a mutation of mutation can lead to the production of amakes it more or less likely
DNA. This type affects an organism if/when it
completely different protein. As a result, the mutation could be
harmful, survive—ONLY mutations in sex cells can affect offspring
to or even fatal, to the organism.
Before Mutation • EX: Cancer can be caused by a
mutation in which cancerous cells
mRNA: A U G A A A U C A U U G
are unable to stop dividing and
Amino acid thus grow uncontrollably
Methionine Lysine Serine Leucine
sequence: • Cancer cells create tumors which
may invade or impair other parts
of the body
After Mutation
Mutation
mRNA: A U G C A A A U C A U U G
Amino acid Methionine Glutamine Isoleucine Isoleucine
sequence:
The addition of a nucleotide can affect the production of an entire protein.
In this case, a mutation has caused an extra C to be added after the first
mRNA codon.

9. Tissue: a group of cells that
carry out a specific
function
• EX: skin tissue protects the
body from microorganisms,
injury and fluid loss
Organs: a collection of
tissues joined together
to perform a common
function
• EX: the heart is a
collection of muscle,
nerve, blood and
connective tissue that
works to pump blood
throughout the body

10. Organ System: a group of organs that work together to
perform a specific function
• EX: The respiratory system includes the nasal passage, airways,
the lungs, other respiratory muscles, etc., and works together to
bring oxygen into the body as well as expel carbon dioxide from
the body (i.e. breathing)

11. Organ systems
work together:
This table
outlines how
the circulatory,
respiratory,
and muscular
system works
with other
organ systems
in the body