Transcript The Biology of Anatomy

The Biology of Anatomy
A review of science past…
The Light Microscope
• Total Power
Magnification: Eyepiece
power multiplied by the
Objective power.
• Usually there are 3
objective powers:
• Low: 4x magnification
• Medium: 10x
magnification
• High: 40x magnification
Plasma Membrane
• The Plasma Membrane & Cell Membrane are
the same thing!
• In an Animal Cell, it is the boundary between
the inside and outside of the cell.
• It is crucial in maintaining the cell’s
homeostasis!!
• It is selectively permeable, meaning it is
choosy about what enters and leaves the cell.
• It keeps nutrients in, and harmful substances
out
Structure of the Plasma Membrane
• The plasma membrane is a
Phospholipid Bilayer
(Phospholipid = Fat,
Bilayer = 2 layers) and has
protein embedded in it.
• Remember, lipids do NOT
dissolve in water, so that is
why cells stay together in
your body that is full of
water!
The round structures with tails
are the Lipids.
The big blue structure is the
Protein.
More on the Phospholipids…
• The “heads” are
hydrophilic (polar) and
are attracted to the water
inside and outside of the
cell.
• The “tails” are
hydrophobic (non polar)
and do NOT like the
water. The tails point to
the middle of the plasma
membrane.
So how do things get in & out??
• Small things are able to
squeeze through the
phospholipid bilayer
and do not cost the cell
any energy.
• Large things must be
pumped into the cell
through one of the large
proteins and this costs
the cell energy!
The General Animal Cell
Organelles & Functions
• Nucleus: Controls the cells activities and holds
DNA.
(Mayor)
• Plasma Membrane: Flexible boundary that controls
what enters and leaves a cell.
(Bouncer)
• Mitochondria: Provide power/energy to the cell and is the
site of cellular respiration.
(Power
Plant)
Endoplasmic Reticulum: Serves as the protein
transport system of the cell.
Smooth E.R.: Has no ribosomes.
Rough E.R.: Has ribosomes.
• Ribosomes: Site of protein
synthesis.
(Factory)
Golgi Body: Modify, package, and sort cellular
materials.
• Centrioles: Helps animal cells divide.
• Cytoskeleton: Gives structure to cytoplasm.
Made of microfilaments (solid) and
microtubules (hollow).
Cytoplasm: The clear fluid of the cell
between the nucleus and cell membrane.
(Swimming Pool)
Lysosomes: Contains digestive enzymes that
break down cellular waste.
Stem Cells
• All cells start out as a general, unspecialized
cell that has the ability to become specialized
according to it’s specific function.
• Here are some examples of specialized cells in
the human body:
Specialized Cells of the Human Body
Red Blood Cells
Nerve Cell (Neuron)
Female Egg
Sperm Cell
DNA
• Stands for Deoxyribonucleic Acid
• Can’t leave the nucleus
• Holds our genetic information
(the way we look!)
• Holds instructions for making
protein
– Enzymes are a protein (remember
that?)
– Enzymes are involved in all actions:
eating, thinking, running!
The Structure of DNA
• DNA is a polymer
• A Nucleotide is the monomer
that makes up the polymer
DNA.
• So, several nucleotides
(monomer) joined together
make up DNA (polymer).
Base Pairing
• Bases pair up and are held
together by a hydrogen bond.
• Adenine always pairs with
Thymine
• Guanine always pairs with
Cytosine.
• These make up the “steps” of the
“ladder”.
• Everyone has errors or mutations
in their DNA, some are minor and
have no impact while others can
give rise to major disease and
illness.
RNA
•
•
•
•
RNA stands for Ribonucleic Acid.
Main function is to make protein.
Found in the nucleus & cytoplasm
Made of nucleotides just like DNA but
with a few differences:
– The sugar is Ribose, instead of
Deoxyribose.
– It is single stranded
– Uses the nitrogen base Uracil in place of
Thymine
Transcription
• Occurs in the nucleus
• The process begins with the DNA unzipping.
• Single-stranded messenger RNA (mRNA) is
made by base pairing. The mRNA is a copy of
the DNA (replacing T with U).
• The mRNA then
separates from the DNA
and the DNA zips back
up.
• The mRNA leaves the
nucleus and goes to a
ribosome in the
cytoplasm.
Translation
• Occurs at the ribosome
• mRNA is read by the ribosome 3 bases at a time.
– These 3 bases are called a codon.
– Each codon on the mRNA CODES for an amino acid.
• Translation begins when the ribosome finds the
codon AUG (Start Codon)
Amino
Acid
Glycine
“Hey, tRNA!
I gotta code for an amino
acid, here! Why don’t you
go fetch it for me!”
“Terrell” tRNA
GGC
“Ref”
Ribosome
• Transfer RNA (tRNA) brings amino acids to the
ribosome.
• Translation stops when the ribosome reads a
STOP codon (there are 3 stop codons).
• Amino acids at the ribosome link together by
a peptide bond to form a protein!
Nucleus
tRNA
Ribosome
mRNA
Start codon
AminoAcid mRNA
Growing polypeptide chain
A.K.A. PROTEIN!!!!
Ribosome
tRNA
Amino Acid
tRNA
mRNA
mRNA
Ribosome Translation direction
Cell Division
• Cells divide to make MORE of themselves by
the process of MITOSIS if it’s a body (somatic)
cell.
• Cancer is uncontrolled cell growth.
Cell Division
• Sex cells (gametes) do a process called
meiosis.
• It looks similar to mitosis, except there is an
extra division and the end result are cells with
HALF the number of chromosomes.