Lecture 5 Flashcards
8 functions of proteins
- Enzymatic
- Defensive
- Storage
- Transport
- Hormonal
- Receptor
- Contractile
- Structural
Monomers of proteins
Amino acids
How many am ac are there
20 diff (differ in R groups)
Cov bond between am ac is
Pep tide bond
What rx is the formation of peptide bond
Condensation rx
Prots also called
Polypeptides (many peptide bonds)
Prot shape determines what
Function
Two diff shapes of prots
Fibrous and globular
Role of fibrous prots
Primarily structural
Where are fibrous prots
Many in EM and in connective tissues for strength and joint mobility
Fibrous prots structure
Long and narrow
Ex of fibrous prots
Collagen, keratin, elastin, silk
Globular prots structure
Typically round in shape
Globular prots functions
Enzymes, cellular messengers, molecular transporters
Globular prots are often soluble in
Aqueous enviros
Ex of globular prots
Hemoglobin, antibodies, enzymes
Slight change in prot structure can
Affect its function (ex sickle cell)
What is sickle cell disease
Single am ac substitution that causes cell to be rigid/mis-shaped
What does sickle cell disease do
Cells stuck together snd block flow of blood/O2 -> pain, infections, tissue damage,loss of eyesight, blood clots and strokes
What is hemoglobin (Hb)
Globular prot in RBC that transports O2, composed of 4 prot chains bound to heme group
Each heme group has at its center
An iron atom
One Hb molecule has 4
Sites to bind O2
What is denaturation of proteins
When they change shape/unfold
What happens if prot denatured
Loss of function
4 ways to denature proteins
- Heat
- Pressure
- Alcohol
- Acids/bases
Enzymes could not fold properly if
Out of their pH range (ex enzyme pepsin pH 2)
How does heat denature
Molecules vibrate so rapidly-> disrupts non covalent bonds
(Ex cooking food, sterilization in medical)
How can fevers be fatal
Denature prots (heat) including enzymes -> damages cells, tissues, organs
Which alcohol is better
70%
Why 70% instead of 95% alcohol
Bc 70% penetrates bacteria cells whereas 95% coagulates on outside of cell without entering
Densturations are not strong enough to break cov bonds between am ac so
Some prots can recover
