Proteins

1
Proteins

• ..a recap

2
Characteristics of Proteins

• Are made up of monomers
• These are called amino acids
• There are 20 amino acids
• And they all have the general molecular
  structure

http//ffden-2.phys.uaf.edu/211.fall2000.web.proje
cts/Danielle20Arnold/Intoduction.html
3
Proteins are coded for by DNA (genes),
transcribed (re-written) to mRNA and then
translated into protein molecules at the ribosome.
http//www.mrothery.co.uk/images/Image46.gif
Youll learn a little more about this year when
we study cell structure, a lot more next year
when you study the molecular basis of genetics.
http//ffden-2.phys.uaf.edu/211.fall2000.web.proje
cts/Danielle20Arnold/Intoduction.html
4
(No Transcript)
5
Polypeptide to Functional Protein

• Refer to your handout Atoms, Molecules and
  Biological Compounds
• The final shape or conformation of a protein is
  determined by the sequence of amino acids it
  contains.
• How a protein functions is determined by its
  three dimensional characteristics.

6
Levels of Structure of a Protein
http//ffden-2.phys.uaf.edu/211.fall2000.web.proje
cts/Danielle20Arnold/Intoduction.html
Roughly linear forming strands or sheets, fibrous
proteins
One or more polypeptide chains take on a rounded,
globular shape
Also check out pg 44-47, Bio-12
7
Campbell Biology
8
(No Transcript)
9
Campbell Biology
10
A couple of questions for you..

• What is and what causes sickle cell anemia? ( pg
  45, Bio-12)
• What makes spider silk so strong?
• What are some examples of proteins in a
  quaternary structure?
• What is denaturation? What is the consequence of
  such an event?
• Check out figure 34 c pg 47 learn how a perm
  works!!
• Read Directions in Science from Handout.

11
(No Transcript)
12
Campbell Biology
13
Campbell Biology
14
Functions of proteins

• Fibrous
• Play a structural role such as collagen found in
  cartilage, bones, tendons, and blood vessels
• Globular
• Regulatory hormones ( growth, insulin, sex)
• Transport hemoglobin, in cell membranes
• Protective antibodies
• Catalytic Enzymes

15
A closer look at a special protein Enzymes

• Answer the following questions so that you
  understand your answers Ref pg 69-72 (12)
• What is an enzyme?
• What is the substrate?
• In simple, simple terms how does an enzyme work?
• Why cant living cells rely on high levels of
  heat to activate metabolic reactions?
• What does the name maltase tell us?
• What things affect enzyme activity?
• Pre-read Investigating the Effect of Temperature
  on Enzyme Activity page 82 (12)

16
Overview What would happen to your cells if they
made a poisonous chemical? You might think that
they would die. In fact, your cells are always
making poisonous chemicals. They do not die
because your cells use enzymes to break down
these poisonous chemicals into harmless
substances.
In this lab, you will study an enzyme that is
found in the cells of many living tissues. The
name of the enzyme is catalase (KAT-uh-LAYSS) it
speeds up a reaction which breaks down hydrogen
peroxide, a toxic chemical, into 2 harmless
substances--water and oxygen. The reaction is as
follows 2H2O2 ----gt 2H2O O2 This reaction is
important to cells because hydrogen peroxide
(H2O2) is produced as a byproduct of many normal
cellular reactions. If the cells did not break
down the hydrogen peroxide, they would be
poisoned and die.
17
Many of these autoxidation reactions do not
produce hydrogen peroxide directly, but rather
superoxide (the product of adding one electron to
an oxygen molecule). In order to get rid of
superoxide (which is more toxic than hydrogen
peroxide) the body also contains lots of
superoxide dismutase, that converts the
superoxide into water and hydrogen peroxide. One
of the most interesting sources of superoxide in
the body is that produced by white blood cells
when they encounter harmful microorganisms. The
white blood cells produce very large amounts of
superoxide, hydrogen peroxide, and even
hypochlorous acid (household bleach!) to kill the
germs, just like in the TV ads.